Traditional rigid robots face significant challenges in congested and tight environments, including bulky size, maneuverability, and safety limitations. Thus, soft continuum robots, inspired by the incredible capabilities of biological appendages such as octopus arms, starfish, and worms, have shown promising performance in complex environments due to their compliance, adaptability, and safety. Different actuation techniques are implemented in soft continuum robots to achieve a smoothly bending backbone, including cable-driven actuators, pneumatic actuators, and hydraulic actuation systems. However, designing and developing efficient actuation mechanisms, motion planning approaches, and control algorithms are challenging due to the high degree of redundancy and non-linearity of soft continuum robots. This article profoundly reviews the merits and drawbacks of soft robots’ actuation systems concerning their applications to provide the readers with a brief review reference to explore the recent development of soft robots’ actuation mechanisms technology. Moreover, the authors have surveyed the recent review studies in controller design of continuum robots as a guidance for future applications.

Flexible robots have exhibited impressive features in working in congested environments due to their compliance behavior and morphological structure. However, designing motion planning techniques and robust control strategies that actively control their deformations are challenging in many applications. Thus, this article presents the learning by Demonstration (LbD) approach for planning the spatial point-to-point motions of a multi-section continuum robot. Via teleoperation, the human demonstrations are captured by moving the flexible interface with similar kinematics of the active robot in front of the Motion Capture System (MCS). Meanwhile, a Nonlinear Model Predictive Control (NMPC) scheme is proposed based on the robot’s kinematic model to follow the reference trajectories while respecting the constraints imposed by the cable lengths and control actions. The simulation results prove the efficiency of the LbD approach in reproducing and generalizing the spatial motions of the robot’s tip and avoiding obstacles and external disturbances. On the other hand, the numerical simulations show the performance of NMPC scheme in terms of trajectory tracking and avoiding static and dynamic obstacles. Additionally, its robustness is analyzed by comparing it to the Pseudo-Inverse Jacobian Kinematic Control (PIJKC) while considering the constraints of cable lengths. Finally, the stability of NMPC is evaluated against input perturbations using the Monte Carlo simulations.

Recently, flexible robots are growing in importance owing to their merits over rigid robots in maneuverability and safety, which equips them to work in unstructured environments, such as occur in medical applications. However, motion planning and control of flexible manipulators is challenging due to their compliance behavior and system uncertainties. Thus, this letter presents an Imitation-based Motion Planning (IbMP) approach, along with dynamic impedance control for learning, planning, and trajectory tracking of a two-section soft continuum robot in a dynamic environment. Point-to-point motion demonstrations, including the robot's tip position and orientation are intuitively provided by a motion capture system (OptiTrack V120-trio) and a similar kinematic flexible interface. Additionally, a singularity-free dynamic model based on Lagrangian formulation and Taylor expansion series of a two-section continuum robot is derived while planning for robot motions. The simulation results show that the IbMP approach, along with the dynamic impedance control, generalizes the robot's motion by varying the initial and goal of the robot's tip pose while avoiding static and dynamic obstacles, and moving back to the desired track after disturbances. Finally, the stability and performance of the IbMP algorithm against input disturbances are assessed using a Monte Carlo approach that can guide the selection of gain values.

With the development of wireless communication systems, a variety of different systems have been studied for controlling mobile robots remotely from a cloud service, often called cloud robotics. In cloud robotics, the quality of wireless links in the wireless communication systems is important to control the mobile robots. Since the quality of wireless links changes for a variety of different reasons, such as moving and blockage, such changes may affect robot control. To operate the mobile robots safely with changing wireless link quality, we proposed a safe operation architecture. Our initial proposal realizes the monitoring of the wireless link status using the heartbeat. When the heartbeat detects the disconnection of the wireless link, the mobile robot automatically stops. However, for safer control of mobile robots, an adaptive control method for the safe operation architecture is required to follow the any change in the wireless link quality because the change is not only a disconnection level but also a gradual status. In this paper, we propose a method of discriminating the wireless link status for adaptive control of mobile robots with changes in the wireless link quality. Our method analyzed the trends in the RSSI to determine the wireless link quality, and the wireless link quality is classified into four statuses to judge the safe operation level of the mobile robot. The evaluation of the proposed method based on the experiments with 60 GHz mobile communication system is presented, and the result shows the usefulness of the method.

Periodic inspection of aging gas pipes is important. However, the conventional inspection approach of excavation is unfriendly to the environment. From the perspective of Sustainable Development Goals (SDGs), in this study, we introduced a pneumatically driven robot system called WATER-7 to observe the inner environment of aging pipes, in particular water inside these pipes, without excavation. The robot can locomote similar to an inchworm with a thrust module operating in a periodical pattern, select direction with an active bending module, and acquire images using a camera. The robot is designed and assembled within a diameter of 12[mm] to enable insertion into a gas meter valve as well as transition and retrieval from a 7[m] service pipe consisting of 8 pipe bends. To improve the driving performance, we also shortened the transit time by increasing air flow and improved the robustness of each module of the robot. Furthermore, an autonomous control system for autonomous burr avoidance based on image processing was developed. According to experiments, the robot average transit time and retrieval without damage count for the assumed scenario were 81[min] and 9 times, respectively. In addition, the autonomous burr avoidance was confirmed to be effective.

Free and structured play should be introduced to children during their childhood in a well-balanced manner. Balls may be used in both plays; therefore, we proposed ball-like robot which will provide children both types of plays. We focused on the jumping of the ball and developed a ball-like jumping robot. In this study, we reported the mechanical design, robot system, performance, and potential of the ball-like robot to jump continuously and turn right/left for controlling the jumping direction. The robot mainly consists of one vibration unit and two compressed springs. Two motions, jumping and turning, are generated by controlling rotation speed of eccentric motors constituting the vibration unit. The experimental results confirmed that the fabricated robot can control the jumping height and average turning angular velocity depending on the rotation speed of the eccentric motors. Furthermore, the robot can be controlled by an operator via commands from a computer with a short delay. The robot can move dynamically. We proposed applications for free and structured play using the ball-like robot from these results.

Many researchers have been studying long and flexible robots, such as snake-like robots and continuum manipulators. The feature of continuum robots is flexibility; therefore, high rigidity has been considered a characteristic to be avoided or unavoidably accepted for controllability. We envisioned a continuum manipulator that takes advantage of both high rigidity and flexibility to enhance its abilities. This paper proposes a concept and an integration method of a new long and flexible manipulator, named Robotic Whip, utilizing both flexible motion and tightening by increasing rigidity. The prototype is 1.4 m in length and 647 g in weight and is actuated by three DC motors rotating winches. Pulling wires enable the device to exhibit an active tightening motion, and loosening wires enable a flexible twining motion. In addition, we estimated the flexible motion of the continuum arm, which consisted of 200 originally designed links, using a simulation based on a rigid links model. Through experiments, it was proven that the prototype performance was adequate, and the device twined around the target bar and enhanced its holding ability by tightening the bar to tow a dolly with a mass of above 2 kg. A comparison of the simulation and actual measurement results showed that our model could reduce the number of prototypes by clarifying the device specifications available for a given situation.

Extensible Soft Robots (ESRs) have increasingly attracted attention, especially in tight and complex environments, owing to their dexterity, and wide reachable workspaces relative to their volume. The existing actuation methods of ESR still suffer from challenges including large dimensions, expensive, complex modeling and control, and limited payload capacity. In this paper, we introduce a novel design for a lightweight, extensible and variable stiffness soft robot-based cable-driven actuation without backbone. The design composes of one section with three segments based on semi-octagon honeycomb structure, wherein the middle segment acts like a soft spring to provide extension feature. Additionally, the top and bottom segments have identical structure with two honeycomb patterns embedded within each other to improve the stiffness of the design. A design analysis is conducted to optimize the proposed structure with respect to stress and displacement. Additionally, a shape estimation approach is utilized to get accurate inference of the prototype's shape based on data acquired from a low-cost Inertial Measurement Unit (IMU) and Motion Capture System (MCS), and constant curvature assumption. A series of experiments including workspace reach-ability, repeatability, shape approximation and payload analysis are carried out to validate the proposed design. The results show that the prototype exhibits good compression/extension ratio up to 42% and 50% relative to its normal length, respectively. Moreover, its payload capability reaches to 565 grams.

The proposed work presents an innovative hybrid parallel robot, combining a delta robot with a spherical parallel manipulator (SPM) to achieve 6-DoF motion. The conceptual design was developed using SolidWorks, showcasing agile movement with required angles. A comprehensive electrical layout design was initiated for ensuring efficient system control, integrating various components such as actuators, sensors, and control units for seamless operation. A forward kinematic model was mathematically developed and implemented in MATLAB, generating trained data by simulating the robot's motion for various input parameters. The trained data represents the robot's position and orientation for different movement types, including linear, circular, pure, and mixed multiple orientation movements. The robot's performance was evaluated using metrics such as position accuracy, orientation error, and response time. This study analyzed the robot's kinematics for precise position and orientation control, conducting tests with square path and helix trajectory movements, as well as sudden and sinusoidal wave motor angle changes. Results demonstrated the robot's platform moved with a pure roll angle, fixed yaw and pitch angles with repetitive roll angle changes, and a small range of roll and pitch angle with a yaw angle, achieving less than 0.2% error in position accuracy and orientation. These findings offer valuable insights for designing and controlling hybrid parallel robots for high-accuracy positioning, highlighting the importance of a well-designed electrical layout, a thorough understanding of the kinematic model, and rigorous performance evaluation for effective system control.

Unmanned aerial vehicles (UAVs) are used in many industrial fields and human-drone interaction (HDI) has seen increasing research attention in recent years. Their ability to fly divides UAVs from other robots and novel social robots are expected to be developed from UAVs in the future. However, touch interaction is critical in social robotics, and ordinary UAVs tend to be unsafe to touch. Furthermore, studies on whole-body interaction between drones and humans, including dancing, are far less common than those with traditional robots. Therefore, we developed 'Soft Flying Robot,' a new type of flying robot for HDI research. Its flight uses helium gas and piezoelectric air pumps, making it blade-free and safe for humans to touch and interact with. In addition, it is equipped with touch sensors and light-emitting units to enable clearer and more immersive interaction. We evaluated Soft Flying Robot by introducing it to a group of performers, observing them use it in a dance workshop, and asking them for their impressions. Initial results indicate that Soft Flying Robot induces new behaviors in users and draws visual attention. This paper mainly discusses the results of the qualitative analysis of Soft Flying Robot's potential in human-drone co-creation.

Soft growing robots have recently attracted considerable interest. They are expected to operate in complicated environments leveraging their flexibility and adaptability. However, some of them are unable to maintain their bending shape without contact with an object, and some of their mechanisms are complex. In this article, we propose a novel heat welding mechanism for pitch-up motion without any support. The proposed robot uses a gusset folded tube and welds its gusset parts. The welded tube is bent, and the robot performs a pitch-up motion. In addition, we experimentally investigate the characteristics of welded bending tubes and develop a stiffness model and bending angle model. The results demonstrate that they depend on the tube diameter, weld shape, and inner pressure. We conducted experiments to evaluate the performance of the robot and confirmed that the maximum bending moment based on which the robot can maintain its bending shape increases under a higher inner pressure, and a large bending angle is obtained by continuous bending. Further, we confirmed that proposed models can adequately simulate the pitch-up motion of the robot. The proposed mechanism enables the robot to perform novel pitch-up motion and expands the application of growing robots.

Lean-diluted combustion can enhance thermal efficiency and reduce exhaust gas emissions from spark-ignited (SI) gasoline engines. However, excessive lean mixture with external dilution leads to combustion instability due to high cycle-to-cycle variations (CCV). The CCV should be controlled as low as possible to achieve stable combustion, high engine performance, and low emissions. Therefore, a stable combustion control function is required to predict the combustion phase with a low calculation load. A machine learning-based function is developed in this work to predict the 50 % mass fraction burn location (MFB50). Input parameters to the machine learning model consist of 1-, 2-, 3-, and 4-cycle from a three-cylinder production-based gasoline engine operated under stoichiometric to the lean-burn mixture. The results show that the MFB50 prediction model achieves high accuracy when 2-cycle data are used relative to 1-cycle data, which implies that the previous cycle data affects the predicted MFB50 of the next cycle. As a result, the neural network model can predict the cyclic MFB50 error within ± 3 °CA CCV and ± 5 °CA CCV with 70 % and 90 % accuracy, respectively. However, an increasing number of cycle data worsens the prediction accuracy due to model over-learning.

This study proposes an insect-Tarsus-inspired leg for a small tree-climbing robot. The expansion of the range of the grippable diameter is a concern for small tree-climbing robots; in this study, we focus on the leg structure of insects that can grip trees of various diameters and reproduce it. The shape memory alloy actuator and superelastic alloy sheet are used to reproduce the bending and extension of the insect tarsus, which is important for gripping. The developed robot with four insect-Tarsus-inspired legs exhibits excellent gripping ability in a cylinder gripping experiment: The range of grippable diameter is 40-250 mm, and the gripping force is 1 N or more. This robot weighs 5.8 g with dimensions of W55 x L60 x H55 mm, and is compact and lightweight; it can exert a gripping force 17 times its own weight over a wide range of diameters. A similar gripping force is confirmed when the Kitayama cedar is gripped. This weight-To-payload ratio is significantly larger than that of conventional tree-climbing robots. This indicates that insect-Tarsus-inspired legs can contribute to improving the gripping ability of small tree-climbing robots.

Wrist rehabilitation robotic devices have delivered the repetitive and gradual training necessary to rehabilitate individuals with wrist impairments properly. Generally, there are two approaches for the design of the wrist rehabilitation devices. In one approach, the motors are placed on the forearm with complex transmission mechanisms to reduce the weight and inertia. In the other approach, rotary motors are placed close to the wrist joints with simple design, and this leads to high weight and inertia. In this paper, a simple design of two-degrees of freedom compliant and balanced wrist rehabilitation device is proposed. It can provide the radial-ulnar deviation and flexion-extension rehabilitation motions. In the proposed design, the servomotors that are placed close to the wrist joints are counterweight balanced to reduce the inertia and the required torques. The balancing is carried out by optimizing the center of mass of the device in the SolidWorks model. A custom design series elastic unit is proposed to be coupled to the servomotor to achieve the compliance for safe human-robot interaction. Based on the device dynamics modeled by ADAMS software, hybrid position and force tracking impedance control is developed for position and force tracking through the different therapeutic exercises. The device is shown to be capable of achieving the different therapeutic exercises compliantly such as the passive, active-assisted and isometric exercises.

Rodents are often used in medicine, brain science, pharmacology, and psychology, as experimental animals. We have been proposing a novel method that involves usages of mobile robots as agents to interact with animals to understand animal behavior. A robot which is able to locomote not only on floors but also walls are strongly expected to increase the variety of behavioral experiments. The purpose of this study is to develop a new mobile robot which is able to locomote both on floor and on walls interacting with rats. For this purpose, we invented a novel mechanism which made a mobile robot locomote by wheels on iron walls. The mechanism consists of an active bending joint in the body, a passive tilting magnet, and a passive tilting tail. We implemented this mechanism into a new small mobile robot, named WR-7 (Waseda Rat No. 7). In this paper, proposed mechanism and its implementation are described.

We developed a small robot with Inline Archimedean Screw Mechanism in response to the demands of surveying Invasive Alien Species (IAS). There are some harmful IAS in wetlands such as snapping turtles. The current method for the survey is net-trap (“Mondori-wana”) and fumbling search by humans. Both methods are inefficient and unsafe for humans. To improve the efficiency and safety of surveying IAS in wetlands, the mobile robot system is demanded. The target environment is configured with soft ground, covered with water, dense water plants and side hole. There is no mobile robot that can move in such an environment. We proposed Inline Archimedean Screw Mechanism to realize locomotion performance at the target environment. The robot can move on a soft land as if cutting a screw. Furthermore, pushing aside water plants, the robot can prevent itself from getting stuck by dense water plants. Using Inline Archimedean Screw Mechanism, we developed the robot, named WANGOT (WAseda Native species Guardian robOT). WANGOT has the size of W85 × H85 × L460 [mm], the weight of 1.4 [kg] and two actuators and four Archimedean screws. It was possible to move forward at a speed of 27 [mm/s] on artificial turf, and the movement performance on the environment of simulated dense water plant area was confirmed.

This paper describes the kinematics, motion planning and mechanism optimization of the dual-arm type cable traversing robot on spatially-structured cable way. Since the inverse kinematics cannot be perfectly defined due to one of the orientation parameters is determined by static condition, its inverse kinematics algorithm utilizing both the kinematics of 3R serial spherical mechanism and the static equilibrium condition of the whole system was developed. The motion planning method to traverse cable node is based on the kinematics and Spherical Linear Interpolation using quaternion. Furthermore, mechanism optimization for avoidance of collision with cables and improvement of characteristics is also conducted.

Lately, robot swarm has widely employed in many applications like search and rescue missions, fire forest detection and navigation in hazard environments. Each robot in a swarm is supposed to move without collision and avoid obstacles while performing the assigned job. Therefore, a formation control is required to achieve the robot swarm three tasks. In this article, we introduce a decentralized formation control algorithm based on the potential field method for robot swarm. Our formation control algorithm is proposed to achieve the three tasks: avoid obstacles in the environment, keep a fixed distance among robots to maintain a formation and perform an assigned task. An artificial neural network is engaged in the online optimization of the parameters of the potential force. Then, real-time experiments are conducted to confirm the reliability and applicability of our proposed decentralized formation control algorithm. The real-time experiment results prove that the proposed decentralized formation control algorithm enables the swarm to avoid obstacles and maintain formation while performing a certain task. The swarm manages to reach a certain goal and tracks a given trajectory. Moreover, the proposed decentralized formation control algorithm enables the swarm to escape from local minima, to pass through two narrow placed obstacles without oscillation near them. From a comparison between the proposed decentralized formation control algorithm and the traditional PFM, we obtained that NN-swarm successes to reach its goal with average accuracy 0.14 m compared to 0.22 m for the T-swarm. The NN-swarm also keeps a fixed distance between robots with a higher swarming error reaches 34.83%, while the T-swarm reaches 23.59%. Also, the NN-swarm is more accurate in tracking a trajectory with a higher tracking error reaches 0.0086 m compared to min. error of T-swarm equals to 0.01 m. Besides, the NN-swarm maintains formation much longer than T-swarm while tracking trajectory reaches 94.31% while the T-swarm reaches 81.07% from the execution time, in environments with different numbers of obstacles.

Soft robotics has recently become a popular topic owing to its advantages over conventional rigid robotics. In this article, we introduce a soft robot that can grow with its own structure; its main components include an inflatable tube for its body and a tip with an expansion mechanism. The tube is made of conventional laminated film. It leads the robot to improved applicability. The robot can grow along the horizontal and vertical directions, and it can bend around yaw and pitch axis. To achieve this, a mechanism feeds air into the inflatable tube for growing the structure, and another heat welding mechanism allows producing bending points where necessary. The experimental results confirm that the proposed robot can grow in mid-air and bend around the yaw axis with varying bending radii. Further, the robot can climb a wall and displace an upper surface by pitch-axis bending. The designed bending structures are very stable because of heat welding; the growing and climbing capabilities depend on the inner pressure of the tube, and these capabilities allow the robot to select various shapes and move seamlessly in various environments.

Nowadays, employing more than one single robot in complex tasks or dangerous environments is highly required. Thus, the formation of multi-mobile robots is an active field. One famous method for formation control is the Potential Field Method due to its simplicity and efficiency in dynamic environments. Therefore, we propose a Fuzzy Inference tuning of the potential field parameters to overcome its limitations. We implement the modified method with tuned parameters on MATLAB and apply it to three TurtleBot3 burger model robots. Then, several real-time experiments are carried out to confirm the applicability and validity of the modified potential filed method to achieve the robots' tasks. The results assert that the TurtleBot3 robots can escape from a local minimum, pass through a narrow passage, and pass between two closely placed obstacles.

The capability of performing animal-like turning action is very important for a biomimetic robot to be used in realistic world. Although the existed biomimetic robots can imitate turning actions of their counterparts, it is still lacking an effective approach to generate bioinspired turning action of small quadruped animals. To solve this problem, we proposed an effective phase-shift-based motion planning method after systematically analyzing and mathematically modeling the turning action of laboratory rats. Moreover, we introduced an N-step turning strategy to allow the biomimetic robot effectively perform animallike turning action regardless of joint limits. We characterized the action similarity between rats and a rat-inspired robot in terms of joint trajectory and their envelope. The robot is able to closely follow the turning action of rats since the difference of turning angle is less than 7.95. Additionally, the width distribution of trajectory envelope between the robot and rat is quite similar. The proposed turning model can be easily extended to biomimetic robots inspired by other small quadruped mammals, which share similar turning patterns to rats.

Recently, continuum flexible robots have been designed for the use in diverse applications; including the exploration of confined static and dynamic environments. One of the challenging tasks for those robots is planning optimal trajectories due to, not only the redundant Degrees of Freedom (DOF) they own but also their compliant behaviour. In this paper, an Imitation-based Pose Planning (IbPP) approach is proposed to teach a two-section continuum robot the motion primitives that will facilitate achieving and generalizing for spatial point-to-point motion which involves both position and orientation goals encoded in a dual quaternion form. Two novel approaches are proposed in this research to intuitively generate the motion demonstrations that will be used in the proposed IbPP. Namely, a flexible input interface, acting as a twin robot, is designed to allow a human to demonstrate different motions for the robot end-effector. Alternatively, as a second approach, the Microsoft Kinect sensor is used to provide motion demonstrations faster via human arm movements. Based on the kinematic model of the two-section continuum robot, a Model Reference Adaptive Control (MRAC) algorithm is developed to achieve tracking the generated trajectory from the IbPP and to guarantee the robustness against the model uncertainties and external disturbances. Moreover, controller stability analysis is developed based on Lyapunov criteria. Finally, simulations are conducted for the two-section continuum robot to prove the ability of the proposed IbPP with the two proposed inputs to learn and generalize for spatial motions, which in future could be easily accommodated for robots with multiple sections. In addition, the proposed MRAC shows a significant performance towards following the required trajectory and rejecting the external disturbance.

Recently, there has been an increased interest in the deployment of continuum robots in unstructured and challenging environments. However, the application of the state-of-the-art motion planning strategies, that have been developed for rigid robots, could be challenging in continuum robots. This, in fact, is due to the compliance that continuum robots possess besides their increased number of degrees of freedom. In this paper, a Demonstration Guided Pose Planning (DGPP) technique is proposed to learn and subsequently plan for spatial point-to-point motions for multi-section continuum robots. Motion demonstrations, including position and orientation, are collected from a human via a flexible input interface that is developed to command the continuum robot intuitively via teleoperation. A dynamic model based on Euler-Lagrange formalism is derived for a two-section continuum robot to be considered while planning for the robot motions. Meanwhile, a Proportional-Derivative (PD) computed torque controller with a Model Reference Adaptive Kinematic Control (MRAKC) scheme are developed to ensure the tracking performance against system uncertainties and disturbances. Also, the system stability analysis based on Lyapunov quadratic equation is proven. Simulation results prove that the proposed DGPP approach, along with the developed control scheme, have the ability to learn, generalize and reproduce spatial motions for a two-section continuum robot while avoiding both static and dynamic obstacles that could exist in the environments.

Following a request by a colleague,wewould like to report the revised results below. These corrections also contain more detailed data, in their proper APA notation, and do not substantively change the results and the discussion. In Section 3.3 (“Results”) of the original article one could read: 1. “being human does not seem to be significantly preferred to machine (p = 0.35 according to Mann- Whitney U-test, and p = 0.45 according to the Chisquared goodness of fit test, confirming the null hypothesis of equal distribution).” which should be replaced by: “being human does not seem to be significantly preferred to machine (X2(1, N = 48) = 0.45, p = 0.502 according to the Chi-square goodness of fit test, confirming the null hypothesis of equal distribution).“ 2. “No significant preference is either found in the category Voice (p = 0.11) through Kruskal-Wallis test, just that high pitch voice is less preferred (p = 0.03) through Chi-squared.” which should be replaced by: “No significant preference is either found in the category Voice (3x2 contingency table Chi-square analysis: X2(2, N = 48) = 1.94, p = 0.38), just that high pitch voice is less preferred (4x2 contingency table Chi-square analysis: X2(3, N = 48) = 11.84, p = 0.008).” 3. “In the category Behaviour, Polite is significantly higher than all the other characteristics (p < 0.001). On the other hand, no preference is found for Direct answer against Detailed neither through Mann-Whitney (p = 0.29) or Chi-squared (p = 0.27)).” which should be replaced by: “In the category Behaviour, Polite is significantly higher than all the other characteristics (X2(3, N = 48) = 59.69, p < 0.0001). On the other hand, no preference is found for Direct answer against Detailed (X2(1, N = 48) = 1.21, p = 0.271).” In Section 4.3.1 (“Semantic scales”) of the original article one can read: 1. “Gathered data were analysed using the Kruskal- Wallis test [43] in case of multiple groups of data and Mann-Whitney U-test [44] in case of two groups of data.” which should be replaced by: “Gathered datawere analysed usingWilcoxon test [43] or Mann-Whitney U-test [44].” 2. “Differential semantic scales were validated calculating Cronbach’s alpha, a coefficient of internal consistency used to estimate the reliability of a psychometric test. Results were: 0.848 for Anthropomorpism; 0.904 for Animacy; 0.835 for Likeability; 0.883 for Perceived intelligence and 0.854 for Familiarity. We conclude that all scales are consistent.” which should be replaced by: “Differential semantic scales were validated calculating Cronbach’s alpha, a coefficient of internal consistency used to estimate the reliability of a psychometric test. Results were, respectively for Ana and Kobiana: 0.82 and 0.85 for Anthropomorphism; 0.89 and 0.92 for Animacy; 0.86 and 0.81 for Likeability; 0.87 and 0.91 Familiarity. We conclude that all scales are consistent.” 3. “Comparing Ana with Kobiana, significant differences are found for Group EV in categories Anthropomorphism (p = 0.003); Likeability (p = 0.021); Familiarity (p = 0.002); Good as receptionist (p = 0.001); and Appropriate voice (p = 0.005), all in favour of Ana. Conversely, for Group CL only category Anthropomorphism is significant (p < 0.0001).” which should be replaced by: “Comparing Ana with Kobiana withWilcoxon test, significant differences are found for Group EV in categories Anthropomorphism (Z = 2.59, p = 0.01); Likeability (p = 0.021); Animacy (Z = 2.01, p = 0.044); Likeability (Z = 2.98, p = 0.003); Familiarity (Z = 4.05, p < 0.001); Good as receptionist (Z = 2.76, p = 0.006); and Appropriate voice (Z = 3.09, p = 0.002), all in favour of Ana. Conversely, for Group CL only category Anthropomorphism is significant (p < 0.0001).” 4. “Apparently, Group CL perceived significantly higher than EV the categories Likeability, Perceived intelligence, Familiarity and Good as receptionist for both robots (p < 0.001 in all cases). Instead, Anthropomorphismwas a different case, as Kobiana was judged significantly (p < 0.001) less anthropomorphic by Group CL compared to group EV.” which should be replaced by: “Apparently, Group CL perceived significantly higher than EV the categories Likeability, Perceived intelligence, Familiarity and Good as receptionist for both robots. Through Mann-Whitney test for Ana: Likeability: U = 82.5, p < 0.0001; Perceived intelligence: U = 176.5, p = 0.0004; Familiarity: U = 133.5, p < 0.0001. For Kobiana: Likeability: U = 81, p < 0.0001; Perceived intelligence: U = 90, p < 0.0001; Familiarity: U = 98, p < 0.0001. Instead, Anthropomorphismwas a different case, as Kobiana was judged significantly (U = 40, p < 0.0001) less anthropomorphic by Group CL compared to group EV.” In Section 4.3.3 (“Voice”) of the original article one can read: 1. “Human voice was rated significantly higher (p < 0.001) than the robotic one. However, it was judged less appropriate for the appearance of Kobiana (p = 0.03), while appropriate for Ana (p = 0.001).” “Human voice was rated significantly higher (Ana: U = 98.5, p = 0.004; Kobiana: U = 124, p = 0.031) than the robotic one. However, it was judged less appropriate for the appearance of Kobiana (U = 117.5, p = 0.021), while appropriate for Ana (U = 80, p = 0.001).” 2. “The second analysis consists in crossing results regarding voice with results on explicit preference. Calculations of Spearman’s Rho reveal a significant (r = 0.46; p = 0.002) correlation between the ratings of explicit preference with the differences of the ratings of the voices of the two receptionists. Finally, another correlation was found between Familiarity and Good voice: Spearman’s test highlighted a significant correlation (r = 0.29; p = 0.007). This means that any of the two receptionists, whenever associated with a bad voice, were rated more uncanny. This correlation is stronger in case of Kobiana (r = 0.52; p = 0.006)” which should be replaced by: “The second analysis consists in crossing results regarding voice with results on explicit preference. Calculations of Spearman’s Rho reveal a significant (r(38) = 0.46, p = 0.0028) correlation between the ratings of explicit preference with the differences of the ratings of the voices of the two receptionists. Finally, another positive correlation was found between Good Voice and Familiarity: This means that a receptionist, whenever associated with a bad voice, was rated more uncanny. This correlation is strong in case of Kobiana (r(38) = 0.52, p = 0.0006).” Finally, in Section “References” of the original article there is the following Ref. [43]: [43] W. H. Kruskal and W. A. Wallis, Use of Ranks in One- Criterion Variance Analysis, Journal of the American Statistical Association, 47, 260 (1952) 583–621, 1952. which should be replaced by: [43] F.Wilcoxon, Individual comparisons by ranking methods, Biometrics Bulletin, 1945, 1(6), 80–83.

We are developing an autonomous monitoring system using mobile robot in response to the demands of autonomous monitoring in forest area. The effective path planning is required for autonomous operation. The robot needs to locomote in the grassy area so as to move in a natural forest area, therefore the path route on grassy area have to be considered. The objective of this study was to develop a path planning method for small mobile robot to move in the forest. We focused on the cost used to generate the path and try to add grass vegetation into the cost map. The grass vegetation degree is effective to generate the optimal path, and the robot could move in forest by following the generated path.

We have developed mobile robots to meet the demand for ecological observation of animals. The purpose of this research is to develop an observation robot specialized for small animals. Robots must have high mobility in forest environments. This robot moves over rough terrain using two active wheels driven by motors and can jump over obstacles by using a two-spring jumping mechanism. The jumping mechanism has a structure that can achieve jumping power even in a forest environment. By this mechanism, it has become possible to jump higher than existing robots in a forest. A spiral cam is used for the jumping mechanism. This cam is effective to achieve a long kicking distance and save space. In this paper, to improve the performance of the robot jumping mechanism, the optimal shape of the cam is examined.

The main goal of robot swarm is to maintain formation among their members while avoiding obstacles and tracking a target in the surrounding environment. One popular approach for achieving this goal is the Potential Field Method (PFM). Thus, in this paper, we propose a formation control algorithm based on the PFM and Fuzzy Inference System (FIS). The Proposed PFM is intended to maintain formation, avoid obstacles and track a moving target as well. We add an interaction potential force to maintain formation beside the attractive and repulsive potential forces. Also, we use the FIS to adapt the change of the relative distances among robots in the swam and other entities int he environment. To test the scalability and reliability of the proposed formation control algorithm, simulations of robot swarms using MATLAB software with a different number of robots following different target trajectories in different environment setups are recorded. Results confirm the efficiency and the applicability the proposed formation control algorithm in achieving the three tasks of the robot swarm.

The interaction test between a robotic rat and living rat is considered as a possible way to quantitatively characterize the rat sociality. In such robot-rat interactions, the robot should be designed to fully replicate a real rat in terms of morphological and behavioral characteristics. To address this problem, a multi-jointed robot prototype has been modified based on our previous work. We optimally update the forelimb of the robot and redesign the control board to make it more dexterous and increase its behavioral capability. Then, we systematically and kinematically analyze the rotational range of joint variables and the workspace of the robot by using traversal method. To evaluate the motion capability of the modified robot, we propose two quantitative parameters: maximum reachable height (MRH) and minimum bendable distance (MBD). Additionally, we achieve to quantitatively evaluate the behavioral similarity between the robot and rat with the calculated accumulative distance (AD) by using dynamic time warping (DTW). These evaluated methods show high promise to improve the robot-rat interaction to be more similar to rat-rat interaction.

In recent years, the importance of inspection technologies for old gas pipes has been advocated. In this study, we developed a robot that moves in gas pipes and acquires pictures of interior of pipes in order to easily identify problems, such as cracks in the walls or water leakages. The robot consists of two balloons and an extension hose, which can be extended or shrunk by means of changing the internal pressure. This mechanism allows the robot to move like an inchworm in gas pipes. The robot also has an active-bending module, driven by air pressure that allows it to pass curved pipe sections. Therefore, the robot can move horizontally and vertically in pipes having an inner diameter of both 28 mm and 53 mm.

Tooth brushing plays an important role in one's health, and particularly, in the prevention of oral diseases. It is a fundamental oral care technique in daily life
however, many elderly or handicapped people cannot brush their teeth without assistance from helpers. The purpose of this study is to develop an automatic teeth cleaning mouthpiece robot. One of the most common methods of brushing teeth is to move the toothbrush along the row of teeth. Hence, a mechanism to wipe teeth using sponges is designed and it consists of an eccentric cam, a wiper with sponges, and a rounded guide rail. This mechanism generates rounded wiper motions along the row of teeth. Furthermore, a safety system is designed to prevent aspiration. Brushing stops automatically when the user lifts his/her jaw up from the jaw supporter.

We developed a small mobile robot in response to the demands in the disaster area. A hybrid locomotion mechanism of wheels and multi-rotors are proposed to realize both high locomotion performance and long-term operation. The wheels allow to highly maneuverable move in a narrow space, and the multi-rotors allow to move to a higher position. The objective of this study is to design the locomotion mechanism and develop a platform for confirming the basic locomotion performance. We attached a wheel mechanism into the assembled hobby drone and embedded an electrical system to operate the robot. The wheels also contribute to protect the multi-rotors from obstacles such as rubble. A stabilizer was proposed to stabilize the robot during running with wheels and designed to allow recover from flipping state. The significant of this work is not only improving the locomotion performance of the drone, but also increase the operating time, this leads various uses at disaster sites. In this paper, the details of the locomotion mechanism and some experimental results using the developed platform are shown.

We are designing an unmanned ground vehicle (UGV) for use in a large-scale and long-Term environmental monitoring system. Existing high-performance UGVs cannot cope with unexpected events because their design concept, like that of almost all previous mobile robots, is based on the development of a single high-performance robot capable of performing every task. To overcome this limitation, we propose using multiple inexpensive robots and operating them such that each compensates for the shortcomings of the others. The objective of this study is to design a robot that could be used to realize a multiple autonomous mobile robot system for long-Term outdoor operation. These robots use only two motors for movement and rely on internal sensors for the control of the robot, thus minimizing the cost. The developed robot is capable of handling unexpected events such that could traverse extreme environments such as forests. The design concept will contribute to the configuration of a multiple robot system and also to increasing the robustness of the overall system. In addition to proposing a robotic system for long-Term operation, this study also proposes a novel idea whereby parts of a robot may be sacrificed to attain the overall objective. In this paper, we describe the details of the wheel and the control design of the robot, and also present the results of some experiments using the developed robot.

The receptionist job, consisting in providing useful indications to visitors in a public office, is one possible employment of social robots. The design and the behaviour of robots expected to be integrated in human societies are crucial issues, and they are dependent on the culture and society in which the robot should be deployed. We study the factors that could be used in the design of a receptionist robot in Brazil, a country with a mix of races and considerable gaps in economic and educational level. This inequality results in the presence of functional illiterate people, unable to use reading, writing and numeracy skills. We invited Brazilian people, including a group of functionally illiterate subjects, to interact with two types of receptionists differing in physical appearance (agent v mechanical robot) and in the sound of the voice (human like v mechanical). Results gathered during the interactions point out a preference for the agent, for the human-like voice and a more intense reaction to stimuli by illiterates. These results provide useful indications that should be considered when designing a receptionist robot, as well as insights on the effect of illiteracy in the interaction.

We present a robot designed for children with developmental disorders. These disorders are categorized into autism spectrum disorder (ASD), attention deficit hyperactivity disorder (ADHD), and learning disability (LD). While growing, children generally learn through play activities. However, those with developmental disorders require external supports during play because they have difficulties in some aspects. For instance, children with ASD tend not to communicate, those with ADHD find it difficult to concentrate, and those with LD have difficulties in talking, reading, writing, and performing calculations. Thus, some researchers propose robots as solutions to enhance the effects of children's play. In this paper, we present a new type of spherical robot that can jump and roll on the floor. The purpose of this research was to develop a spherical robot that engages with children using its motion capabilities. Specifically, here we present the mechanical design and performance of the robot. The robot has two types of outer spheres with a diameter of 170 mm and made from varied materials. One is a soft sphere made of paper, and the other is a plastic hard sphere. As a result, the jumping height of the internal mechanism reaches 110 mm, that of the soft sphere reaches 65 mm, and that of the hard sphere goes up to 10 mm The robot speed using the hard sphere is 0.65 m/s. In contrast, the robot with the soft sphere exhibits an unstable rolling motion, a seemingly dancing pace, which is difficult to control. Overall, we consider that the proposed jumping and rolling spherical robot can be a suitable tool to aid children with developmental disorders.

The ability of climbing steps and slopes are required for on-land tiny mobile robot to move on rough terrain in the riverside area. We have already proposed a new wheel shape
notched wheel that can satisfy the maximum potential of the abilities and easily calculate the abilities. However, the model has not mentioned the phase difference between the left and right wheels. We found that the method of phase difference is so effective to improve the climbing ability of slopes. The climbing step ability become high when the right side of the notched wheels is π/2 different from left side wheels. In this paper, we describe the details of the methods and show some experimental results.

A mobile robot for monitoring of forests was developed. The robot has a 3D scanner, and leg-like-wheels to move around in the forests. An experiment was performed in a forest in Namie-machi, Fukushima. Performance of the 3D scanner was verified in the experiment.

The locomotion ability of climbing steps and slopes are required for tiny mobile robot to move on rough terrain such as forest or river side area. A lot of studies proposed the specially shaped wheels to use in particular environment, but these mechanism is not clear to understand the ability of climbing steps and slopes. In this study, we proposed a notched wheel that has both high climbing abilities of steps and slopes and easily calculate its ability. We show some model of a notched wheel and describe its detail mechanism. In this paper, we also show some experimental results of mobile robot that have four notched wheels. This study is significant not only because it fills gaps in previous research, but also because it is useful to design the specially shaped wheels.

The objective of this study was to design a new model of wheel shape for increasing climbing ability of slopes and steps. We made a new model using a statics for calculating the ability easily and found that the arc-shaped notch type seems to be the best and implemented to our robot. In this paper, we introduce the detail of the proposed model and simulation results.

One of the main problems faced by land-based mobile robots is their locomotion performance on rough outdoor terrain. We focused on the navigation of grassy areas such as riversides and forests. These have many types of obstacles, which make robot locomotion difficult. Several studies have been conducted on locomotive mechanisms for rough terrains that have performed well. However, most of these mechanisms cannot pass through grass taller than their own height while using a small number of actuators. We designed a novel mechanism that uses only two motors to ensure a high locomotive ability over a field with tall grasses. We also designed "Grassbreaker" by attaching an outer covering to a tiny mobile robot shaped like an icebreaker. We found that the robot's shape greatly influences its mobility in a tall grass field and that the robot continued to move forward while bending tall grasses such as reeds. The significant difference (p &lt
0.05) between the average speeds of Grassbreaker and the robot without the outer covering was confirmed in an experiment. The robot's new shape is significant not only because it fills a gap in previous research work but also because this method does not require any additional actuators such as conventional cutting and bending methods.

One of the main problems faced by land-based mobile robots is their locomotion performance on rough outdoor terrain. We focused on the navigation of grassy areas such as riversides and forests. These have many types of obstacles, which make robot locomotion difficult. Several studies have been conducted on locomotive mechanisms for rough terrains that have performed well. However, most of these mechanisms cannot pass through grass taller than their own height while using a small number of actuators. We designed a novel mechanism that uses only two motors to ensure a high locomotive ability over a field with tall grasses. We also designed "Grassbreaker" by attaching an outer covering to a tiny mobile robot shaped like an icebreaker. We found that the robot's shape greatly influences its mobility in a tall grass field and that the robot continued to move forward while bending tall grasses such as reeds. The significant difference (p &lt
0.05) between the average speeds of Grassbreaker and the robot without the outer covering was confirmed in an experiment. The robot's new shape is significant not only because it fills a gap in previous research work but also because this method does not require any additional actuators such as conventional cutting and bending methods.

We developed a four-arm four-crawler advanced disaster response robot called OCTOPUS. Disaster response robots are expected to be capable of both mobility, e.g., entering narrow spaces over very rough unstable ground, and workability, e.g., conducting complex debris-demolition work. However, conventional disaster response robots are specialized in either mobility or workability. Moreover, strategies to independently enhance the capability of crawlers for mobility and arms for workability will increase the robot size and weight. To balance environmental applicability with the mobility and workability, OCTOPUS is equipped with a mutual complementary strategy between its arms and crawlers. The four arms conduct complex tasks while ensuring stabilization when climbing steps. The four crawlers translate rough terrain while avoiding toppling over when conducting demolition work. OCTOPUS is hydraulic driven and teleoperated by two operators. To evaluate the performance of OCTOPUS, we conducted preliminary experiments involving climbing high steps and removing attached objects by using the four arms. The results showed that OCTOPUS completed the two tasks by adequately coordinating its four arms and four crawlers and improvement in operability needs.

Humanoid robots are expected to be able to communicate with humans using physical interaction, including hug, which is a common gesture of affection. In order to achieve that, their physical embodiment has to be carefully planned, as a user-friendly design will facilitate interaction and minimise repulsion. In this paper, we investigate the effect of manipulating the visual/tactile appearance of a robot, covering wires and metallic parts with clothes, and the auditory effect by enabling or disabling the connector of the hand. The experiment consists in a hugging interaction between the participants and the humanoid robot ARMAR-IIIb. Results after participation of 24 subjects confirm the positive effect from using clothes to modify the appearance and the negative effect of noise and vibration.

The demand for monitoring from high points is increasing to support remote control and accurate monitoring. Unmanned ground vehicles with long arms are used to achieve long-term and accurate monitoring. The use of convex steel tapes is effective for achieving both high strength and lightness of the arm, which prevents the robot from collapsing or the arm from falling off. However, the previously proposed methods could not be used under tough environmental conditions such as strong winds as well as when the posture of the robot is changed. The objective of the present study is to design a novel extendable arm structure using convex tapes for outdoor usage. We designed an arm with a novel combination of convex tapes that can endure outdoor interferences. We manufactured the arm using a new method such that there is no need to separate the convex tapes. Our results indicated that the robot could extend its arm up to 4 m at a wind speed of 10 m/s and its posture can be changed to 15 degrees in all directions without the use of additional supports such as an outrigger. This novel arm is useful for supporting remote-controlled aerial work platform outdoors such as in a disaster struck area where only tiny mobile robots can enter. This novel combination method is significant not only because it fills the gap in previous sutures but also because it does not require complex mechanisms such as the outrigger method.

Neurological examination takes an important role in the clinical examination, and requires both deep medical knowledge and high clinical skills. Until now, several education methods for neurological examination have been proposed, such as lectures using videos, and skill trainings with manikins or simulated patients (SPs). However, complex physical skills, such as examination of the upper limbs, are difficult to obtain for inexperienced physicians both in lectures and in skill trainings. In this paper, we propose an arm robot named WKE-3(Waseda Kyotokagaku Elbow Robot No.3) for skill trainings of neurological examination, as a part of the whole body patient robot named WKP (Waseda Kyotokagaku Patient). A novel mechanism, which can simulate both active and passive movement, is implemented in the elbow joint to simulate various symptoms.

Locomotive performance is one of the most important issues for land-based mobile robots, which is designed to be used in natural environment, such as grass fields or forests. We propose a novel method to change outer shape of the robot to increase locomotive performance in natural environment. The robots, which are designed using this method, does not require additional actuators, while conventional mobile robots obtain higher locomotive performance in natural environment using multiple actuators. The objective of this study is to propose a novel design method of outer shape of mobile robots, which is inspired from "icebreakers". Through experiments, we confirmed that locomotive performance is greatly affected by outer shape of mobile robots.

In recent years, demands for outdoor mobile robots, such as those for agriculture or environmental monitoring, are increasing. Power supply is one of the most important considerations for these robots, and autonomous battery charging system can be one solution. The objective of this study is to develop a prototype battery charging system for outdoor mobile robots, using wireless power transmission technology. We developed a battery charging station and a power receiver for a mobile robot. The receiver coil was implemented in WAMOT-2, which had been developed for the monitoring. Operation of the system was verified through an experiment.

Drawbacks of conventional colonoscopy include the risk of accidental injury and a dependence on the operator's skill. This study presents a novel minimally invasive self-propelled colonoscope robot. We developed an active-bending module, made with pneumatic parallel links with three degrees of freedom, and assembled in a robot (WQE-5) propelled by a "party horn" mechanism with a thrust generator. We confirm the increase in the passing speed in the curved section of a colon model, achieved by the winding of WQE-5.

Purpose: Current training for laparoscopy focuses only on the enhancement of manual skill and does not give advice on improving trainees’ posture. However, a poor posture can result in increased static muscle loading, faster fatigue, and impaired psychomotor task performance. In this paper, the authors propose a method, named subliminal persuasion, which gives the trainee real-time advice for correcting the upper limb posture during laparoscopic training like the expert but leads to a lower increment in the workload. Methods: A 9-axis inertial measurement unit was used to compute the upper limb posture, and a Detection Reaction Time device was developed and used to measure the workload. A monitor displayed not only images from laparoscope, but also a visual stimulus, a transparent red cross superimposed to the laparoscopic images, when the trainee had incorrect upper limb posture. One group was exposed, when their posture was not correct during training, to a short (about 33 ms) subliminal visual stimulus. The control group instead was exposed to longer (about 660 ms) supraliminal visual stimuli. Results: We found that subliminal visual stimulation is a valid method to improve trainees’ upper limb posture during laparoscopic training. Moreover, the additional workload required for subconscious processing of subliminal visual stimuli is less than the one required for supraliminal visual stimuli, which is processed instead at the conscious level. Conclusions: We propose subliminal persuasion as a method to give subconscious real-time stimuli to improve upper limb posture during laparoscopic training. Its effectiveness and efficiency were confirmed against supraliminal stimuli transmitted at the conscious level: Subliminal persuasion improved upper limb posture of trainees, with a smaller increase on the overall workload.

In this paper, we study the behavioral response of rats to a robotic rat during multi-rat interaction. Experiments are conducted in an open-field where a robotic rat called WR-5 is put together with three laboratory rats. WR-5 is following one rat (target), while avoiding the other two rats (outside observers) during interaction. The behavioral characteristics of each target rat is evaluated by scoring its locomotor activity and frequencies of performing rearing, body grooming and mounting actions. Additionally, the frequency of being mounted by other rats is also measured. Experimental results show that the target becomes more active after interaction. The rat species, with more active behavioral characteristics, is more susceptible to being adjusted by the robot. The increased time spent by the outside observers in the vicinity of the robot indicates that a biomimetic robot has the promise for modulating rat behavior even without direct interaction. Thus, this study provide a novel approach to shaping the sociality of animals living in groups.

© 2015 IEEE. In the near future, robots are expected to perform assistive tasks and do different kind of jobs. In particular, humanoid robots are possible candidates for being used as helpers in activities of daily living. One possible employment is working as a receptionist, providing useful indications to visitors in a public office. The design of how robots could look like is a matter of growing importance, as it is important to create a look that poses no uncanny valley effects on the human user and that is appropriate to potentially serve in different job areas in human society. In this paper we want to describe the study on anthropomorphism of a receptionist robot. We invited Brazilian people with different education levels to interact with two variations of a receptionist robot, different in physical appearance as well as in the sound of the voice. In one case, the appearance was a conversational agent made with computer graphics, in the other, a real humanoid robot. Results gathered from surveys and comments of the participants provide useful directions to design a receptionist robot and insights on the effect of digital divide on anthropomorphism.

In this paper, we describe the system design and control of a miniature robotic rat, WR-5, which is intended to interact with laboratory rats. WR-5 can perform rearing, mounting, rotating, and body-grooming actions as naturally as live mature rats because of its multilink structure. Experimental results confirm that WR-5 can stimulate stressing fear in rats by performing a mounting action, which shows remarkable progress when compared with the previous generation of these robots. Additionally, a virtual impedance model-based control method is used to generate both posture and trajectory for WR-5. The results of simulations and following tests with real rats show that WR-5 can adjust its head and body positioning to follow a target rat in real time. The control system simultaneously allows real-time avoidance of moving outside observers during the following test. Additionally, based on interaction with multiple rats, we conclude that the robotic rat shows great promise for manipulation of the sociality of rats.

Postural stability degrades with age, threating the health and life quality of the older adults. One Leg Stance (OLS) is one of the standard and commonly adopted assessments for postural stability, and the postural sway in OLS has been demonstrated to be related with age. The propagation of postural sway between body segments could be a hint to the underlying mechanism of balance control. However, it is not yet fully understood. Therefore, the aim of this paper was to study the angular sways and their propagation of the head, trunk, and lower limb in healthy older adults. A cross-correlation of the normalized angular speeds was performed and the experiment with 68 older adults was conducted. The results showed that the head, hip and ankle joints affected the transfer of angular sway with a relatively lower correlation and longer latency.

Robots are possible candidates for performing tasks as helpers in activities of daily living in the future: working as a receptionist is one possible employment. However, the way the receptionist robot should appear, sound and behave needs to be investigated carefully, in order to design a robot which is accepted and perceived in a positive way by common users. This paper describes a study on anthropomorphism of a receptionist robot made for Brazilian people depending on the appearance and on the voice of the receptionist. This experiment was preceded by a preliminary survey about expectation of people regarding receptionists. The main experiment consisted in having Brazilian people interacting with a conversational agent and with a humanoid robot through a video conference. The two receptionists are not only different in physical appearance, but in the sound of the voice, too, which can be either human-like or robotic sound. The two receptionists gave indications to the participants to reach rooms where they could evaluate the receptionists through questionnaires concerning anthropomorphism and uncanniness among other concepts. The results gathered from both experiments provide useful hints to design a receptionist robot.

Environment recognition is an effective way for a mobile robot to move across rough terrain. In particular, this makes it possible to prevent a tiny mobile robot from getting stuck or turning over. Several studies have been conducted on environment recognition using a laser range finder or camera. However, almost all of these studies focused on obstacle detection or shape recognition, which cannot be used to recognize the surface condition such as slipperiness. The purpose of this work is to design a model for estimating the surface condition using a tiny mobile robot. We set slipperiness as one of the parameters for recognizing the surface condition, which is already used by terramechanics, along with two additional parameters, the hardness and unevenness. We find that a robot can roughly estimate the ground hardness by measuring the current peak of a motor and the unevenness from measuring the robot posture. By recognizing the surface condition, the robot can change the parameters of the controlling motor based on the ground characteristics. This new method for recognizing the surface condition is significant, not only because it fills gaps in the previous research, but also because it does not require any special sensors such as a laser range finder and does not consume a large quantity of energy. Therefore, it achieves a core objective of our environmental monitoring system using multiple mobile robot.

Nowadays, the technologies for detecting, processing and interpreting bioelectrical signals have improved tremendously. In particular, surface electromyography (sEMG) has gained momentum in a wide range of applications in various fields. However, sEMG sensing has several shortcomings, the most important being: measurements are heavily sensible to individual differences, sensors are difficult to position and very expensive. In this paper, the authors will present an innovative muscle contraction sensing device (MC sensor), aiming to replace sEMG sensing in the field of muscle movement analysis. Compared with sEMG, this sensor is easier to position, setup and use, less dependent from individual differences, and less expensive. Preliminary experiments, described in this paper, confirm that MC sensing is suitable for muscle contraction analysis, and compare the results of sEMG and MC sensor for the measurement of forearm muscle contraction.

Different types of sensors are being used to study deglutition and mastication. These often suffer from problems related to portability, cost, reliability, comfort etc. that make it difficult to use for long term studies. An inertial measurement based sensor seems a good fit in this application; however its use has not been explored much for the specific application of deglutition research. In this paper, we present a system comprised of an IMU and EMG sensor that are integrated together as a single system. With a preliminary experiment, we determine that the system can be used for measuring the head-neck posture during swallowing in addition to other parameters during the swallowing phase. The EMG sensor may not always be a reliable source of physiological data especially for small clustered muscles like the ones responsible for swallowing. In this case, we explore the possibility of using gyroscopic data for the recognition of deglutition events.

This study aims to develop a state transition model and speech recognition module for application to a whole-body patient simulator for scenario based training (SBT) of neurological examination procedures. These procedures are very important for the early identification of neurological system disorders. In neurological examinations, the doctor selects procedures by situation of patients, interacts with the patient and performs a series of medical procedures to judge the site of nerve disorders and lesions. SBT is one type of training that doctor performs to be based on scenario. Scenario is patient situation and examination procedure. SBT is used for the training of such examinations. SBT is often performed using simulated patients (SPs); however, the number of SPs is not sufficient and SPs cannot adequately reproduce diseases. Therefore, we integrated a state transition model with a commercial speech recognition software and developed a dialogue system for SBT. First, we customized the grammatical rules and the different words that the software can recognize. By doing so, the recognition rate improved to about 90%. Second, we developed a probability model for the state transition model. In neurological examinations, patient pause is limited and an order of procedures is generally decided. We developed a state transition model including probability model with the customized speech recognition module.

In the past we achieved to use a rat-like robot and a single rat to develop Animal Models of Mental Disorder (AMMDs) through stress exposure. However, to simulate the real social environment, we use a rat-like robot composed of multiple links to chase a specific rat (target) in a group of rats (outside observers). In this paper, we aim to develop a real-time control system for a multi-link robot surrounded by multiple rats. A virtual impedance model was adopted to generate posture and trajectory for a multi-link robot named WR-5. With the analysis of virtual forces/moments acting on WR-5 based on the model, corresponding dynamic equations can be obtained to control the motion of WR-5. Simulation results show that the head of WR-5 can accurately direct a target object in the following test. After conducting experiments with three rat subjects (a target rat, two outside observers), the output results suggest that the head and body gesture of WR-5 achieves to follow the target in real-time. Meanwhile, the control system allows real-time avoidance of the moving outside observers during interaction.

Endotracheal intubation (ETI) is a difficult technique and requires a great deal of practice to master. Research on the difference in movements between experts and novices performing the procedure has shown that experts perform movements more precisely than novices. Experts keep a fixed posture and use the upper arm muscles and wrist joints more effectively. These studies were conducted using optical motion capture systems and surface electromyography (sEMG), which are measurement systems that require a long setup time and expensive equipment. In this paper, we propose a novel method to measure the biomechanical performance of doctors during ETI using an innovative muscle contraction sensing device (MC sensor) and inertial measurement units (IMUs). We performed several experiments to measure the movements of both experts and novices performing ETI and then analysed and compared the obtained data. The results clearly showed that our system, comprising an MC sensor and IMUs, allows for an objective evaluation of ETI skills and highlighted the major differences between the movements of novices and experts.

Environmental monitoring robot is a new method for approaching environmental monitoring. The main issue with the development of this is to develop accessible its system. Several studies have been conducted on the autonomous monitoring system and they performed well, however, almost they are costly and complex therefore be not considered well to be accessible design. The purpose of our work was to develop an accessible system and implement to root for other field's researchers. The objectives of the work were to design operating software and electrical system that could be easily used to operate the robot and monitor the environment as a monitoring system. The middle sections of the article introduce and describe specific information about these objectives. We also explain the results of its experimental implementations to an autonomous environmental monitoring robot named Waseda Animal Monitoring robot (WAMOT). An operating software and electrical system were successfully designed by using the existing infrastructure and product, especially, smartphone and public cloud server were used for making the robot easy to use. The developed method is significant, not only because it fills a gap in the mobile robot, but also because it makes possible to adapt to the conventional monitoring method such as monitoring post. Therefore, achieves the core concept of accessibility.

In this paper, we study the response of a rat to a rat-like robot capable of generating different types of behaviour (stressful, friendly, neutral). Experiments are conducted in an open-field where a rat-like robot called WR-4 is put together with live rats. The activity level of each rat subject is evaluated by scoring its locomotor activity and frequencies of performing rearing (rising up on its hind limbs) and body grooming (body cuddling and head curling) actions, whereas the degree of preference of that is indicated by the robot-rat distance and the frequency of contacting WR-4. The moving speed and behaviour of WR-4 are controlled in real-time based on the feedback from rat motion. The activity level and degree of preference of rats for each experimental condition are analysed and compared to understand the influence of robot behaviour. The results of this study show that the activity level and degree of preference of the rat decrease when exposed to a stressful robot, and increase when the robot exhibit friendly behaviour, suggesting that a rat-like robot can modulate rat behaviour in a controllable, predictable way. © 2013 IOP Publishing Ltd.

We developed a novel small rat-like robot called Waseda Rat No. 4 (WR-4) to interact with real rats. WR-4 can perform both rearing (rising up on its hind limbs) and rotating (body bending during movement) actions faster than live mature rats. After robot-rat interaction involving rearing and body grooming (body cuddling and head curling) actions of WR-4, real rats showed more activity and greater interest in the robot. Similar results evident from rat-rat interaction suggest that a rat-like robot is able to interact with rats in the same way as real rats. Furthermore, lower variances between the rat subjects in robot-rat interaction reveals that a rat-like robot can more effectively impact rat's behavior in a controllable, predictable way.

The purpose of this study was to determine safe techniques of performing blood collection using an evacuated tube system, particularly with regard to manipulation of the equipment and at the puncture site. Careful observation of the procedure was used to collect data for evaluating the various venepuncture techniques. Nurses were digitally videotaped performing simulated venepuncture. A self-administered questionnaire and unstructured observation of a videotaped recording were evaluated, and valid responses were analyzed from participants who performed venepuncture using various techniques. The participants who changed hands during the procedure were older than those who did not change hands. Needle movements during puncture and insertion, including rotation and insertion in a wave-like trajectory, were observed. Appropriate training, including recommendations for maintaining the stability of the needle tip, is important to ensure safety when performing venepuncture. Movement of the needle should not place too much pressure on the puncture site.

This paper presents a methodology for a reliable comparison among Inertial Measurement Units or attitude estimation devices in a Vicon environment. The misalignment among the reference systems and the lack of synchronization among the devices are the main problems for the correct performance evaluation using Vicon as reference measurement system. We propose a genetic algorithm coupled with Dynamic Time Warping (DTW) to solve these issues. To validate the efficacy of the methodology, a performance comparison is implemented between the WB-3 ultra-miniaturized Inertial Measurement Unit (IMU), developed by our group, with the commercial IMU InertiaCube3 (TM) by InterSense.

Background and aim The Japanese Society of Pediatric Endoscopic Surgeons developed an endoscopic surgical skill qualification (ESSQ) system. However, this is a subjective system we developed and validated an objective skill evaluation system for pediatric surgeons. Methods In the ESSQ system, the task operation is laparoscopic fundoplication. Therefore, we set up a suture ligature model of the crura of the diaphragm for infant fundoplication. Examinees were divided into 2 groups, 10 experts and 16 trainees. They had to perform two suture ligatures of the crura using an intracorporeal knot in the box. Evaluation points were time, force on the tissue, suture tension, stitch spacing, equidistance, mean score, and total score. Statistical analysis was performed and p&lt
0.05 was considered statistically significant. Results Experts showed better score than trainees in the time score (p&lt
0.0001), the score for force on the tissue (p&lt
0.0001), the stitch spacing score (p&lt
0.05), the equidistance score (p\\0.005), the mean score (p&lt
0.0001), and the total score (p&lt
0.0005), respectively. Conclusion The results revealed that the expert group possessed gentle and speedy skills compared with that of the novices. Using this validation study, our established model could be used to objectively evaluate the endoscopic surgical skills of pediatric surgeons. © Springer-Verlag Berlin Heidelberg 2013.

Performing laparoscopic surgery requires several skills, which have never been required for conventional open surgery. Surgeons experience difficulties in learning and mastering these techniques. Various training methods and metrics have been developed to assess and improve surgeon's operative abilities. While these training metrics are currently widely being used, skill evaluation methods are still far from being objective in the regular laparoscopic skill education. This study proposes a methodology of defining a processing model that objectively evaluates surgical movement performance in the routine laparoscopic training course. Our approach is based on the analysis of kinematic data describing the movements of surgeon's upper limbs. An ultraminiaturized wearable motion capture system (Waseda Bioinstrumentation system WB-3), therefore, has been developed to measure and analyze these movements. The data processing model was trained by using the subjects' motion features acquired from the WB-3 system and further validated to classify the expertise levels of the subjects with different laparoscopic experience. Experimental results show that the proposed methodology can be efficiently used both for quantitative assessment of surgical movement performance, and for the discrimination between expert surgeons and novices.

Physicians use ultrasound scans to obtain real-time images of internal organs, because such scans are safe and inexpensive. However, people in remote areas face difficulties to be scanned due to aging society and physician's shortage. Hence, it is important to develop an autonomous robotic system to perform remote ultrasound scans. Previously, we developed a robotic system for automatic ultrasound scan focusing on human's liver. In order to make it a completely autonomous system, we present in this paper a way to autonomously localize the epigastric region as the starting position for the automatic ultrasound scan. An image processing algorithm marks the umbilicus and mammary papillae on a digital photograph of the patient's abdomen. Then, we made estimation for the location of the epigastric region using the distances between these landmarks. A supporting algorithm distinguishes rib position from epigastrium using the relationship between force and displacement. We implemented these algorithms with the automatic scanning system into an apparatus: a Mitsubishi Electric's MELFA RV-1 six axis manipulator. Tests on 14 healthy male subjects showed the apparatus located the epigastric region with a success rate of 94%. The results suggest that image recognition was effective in localizing a human body part.

Robotics is contributing to studies on animal behavior. Mobile robots are actually used as devices to give external stimulus to animals in several experiments. We consider that this approach can be applied to studies in psychic medicine. In psychic medicine, all new drugs are evaluated in experiments using animal models of mental disorder before using it in clinical practice. However, conventional animal models have some problems in the construct validity. The animal models should be developed through the method which is consistently associated with the theory of the mental disorders while many of conventional models had been developed by genetic manipulations or surgical operations on nerve system. We considered that a novel animal model could be developed by stress exposure using a small mobile robot. We then implemented this method to the experimental system which had been developed in our past study. An experiment was conducted using the system, and the method was then verified. Therefore, we conclude that the animal model of depression developed by proposed method, exposing continuous attack by the robot in immature period and interactive attack in mature period, can be a novel animal model of depression.

The cranial nerves examination is one part of neurological examination. Neurologic medical staffs, especially the novices, need to be trained and grasp this skill. There are various methodologies to help the trainee to accumulate experiences. However, the best way is to practice on the real patient. The methods have their own drawbacks such as lack of active interactions, limitation of multi-symptoms' reproducing, etc. In order to improve the training effectiveness, a face robot (Fig. 1) is proposed in this paper for cranial nerves examination training as one part of the whole body patient robot named WKP (Waseda Kotokagaku Patient). In this robot, various symptoms of optical tracking, eyeball movements, facial paralysis are simulated and shown to the trainee. Finally, a set of experiments was performed to evaluate our proposed mechanism and control system. Three neurologists with over 30 years' experience were invited to show their opinions on the reproductions of the symptoms, and to discuss the results. All the results lead to the improvements for further research.

Neurologic examination takes an important role in diagnosis of the nerve system diseases. Neurologic medical staffs, especially the novices, need to be trained on this skill. There are many methodologies which can help to accumulate experiences, such as watching video, reading books, making use of the simulated patient (SP), and so on. However, the best way is to practice on the real patient. All the above methods have their own drawbacks such as lack of active interactions, limitation of multi-symptoms' reproducing, etc. To improve the training effectiveness, an arm robot is proposed in this paper for neurologic examination training as one part of the whole body patient robot named Waseda Kyotokagaku Patient (WKP). In this robot, various symptoms of the elbow force, biceps tendon reflex, involuntary action, and so on, are simulated and shown to the trainee. Finally, a set of experiments was carried out to verify our proposed mechanism and control system. Three neurologists with over 30 years' experience were invited to show their opinions on the reproductions of patients' symptoms, and to discuss the results. The effectiveness of this system was confirmed. The experimental results lead to the consideration that the approach is worth following in further research.

In the last years there has been increasing interest on Inertial Measurement Units (IMUs) in several fields, because they can provide a measurement of the orientation, velocity, and acceleration at low cost with high performance. The main reason of the low cost is the possibility to find inertial sensors, as accelerometers, gyroscopes and magnetometers, based on Micro-Electro-Mechanical Systems (MEMS) made by silicon, with further advantages of small dimensions and mass production from the main semiconductor suppliers. In this paper, we present the development of the ultra miniaturized wireless IMU, WB-4 (Waseda Bioinstrumentation number 4), with a 3-axis accelerometer, 3-axis gyroscope and 3-axis magnetometer. Additionally, we illustrate, together with results, the algorithms used for the data filtering and calibration, with particular emphasis on a new methodology for the online calibration of the digital magnetometer.

In this paper, we proposed an automated video processing system to replace the traditional manual annotation, and to improve the adaptivity of the rat-like robot to autonomously interact with rats. The feature parameters of rats, such as body length, body area, circularity, body bend angle, locomotion speed, etc., are extracted based on image processing. These parameters are integrated as the input feature vector of Artificial Neural Network (ANN) and Support Vector Machine (SVM) classification methods respectively. Preliminary experiments reveal that the rearing, grooming and rotating actions could be recognized with extremely high rate (more than 90% by SVM and more than 80% by ANN). Furthermore, SVM needs less training computational cost than ANN. Therefore, SVM is superior to ANN for the behavior recognition of rats. By using the SVM-based recognition system, the behavior of the robot is generated adaptive to the rat behavior for different interactions.

The purpose of this study is to develop novel training system for medical skills using robot technology. We have developed Waseda Kyotokagaku Airway No.4 (WKA-4) as a novel training simulator for airway management. This robot reproduces several different patients with actuators. For instance, this robot has a unique mechanism in its temporomandibular joint that consists of a set of warm gears and force sensors, hence reproduces a patient with TMJ disorder. This robot also has the tongue that is able to change its shape using air pressure, hence reproduces the difficulty of airway management. We then asked the medical doctors to evaluate the robot using a questionnaire and confirmed that WKA-4 had enough property to use in the training of anesthesiologists.

The number of patients with mental disorders is increasing in advanced countries, hence more effective psychotropic drugs are recently desired. In process of development of psychotropic drugs, animal experiments have been playing a very important role. Mental disorder model animals which exhibit behavior disorder like patients with mental disorders are used in these experiments. These animals are normally developed by genetic manipulation, surgical operation in their brain or drug administration. A candidate for a new drug is administrated in these animals to evaluate its effect. However, we have some doubts about conventional mental disorder model animals because they are induced these disorders by using methods which are quite different from causes of mental disorder of human beings. Therefore, the purpose of this study is to develop an novel methodology to create mental disorder model animals. We then developed a small mobile robot and a control system for it. Using them, we have performed some experiments to create a mental disorder model rat. We had then succeeded in developing a mental disorder model rat by exposing stress using the robot during immature period. This rat exhibits low activity in some behavior tests during mature period. For better understanding of how stress exposure induces mental disorder in a rat, we conducted another experiment based on stress vulnerability hypothesis. In this experiment, stress was exposed during both immature and mature period while that had been exposed only during immature period. We prepared several conditions of stress exposure by changing robot behavior pattern to find the one to induce much stress in a rat. From a result of experiment, we found that a rat which received gentle chase by the robot during immature period was induced much stress when it received robot attack during mature period. Thus, we consider that this rat is more appropriate to the mental disorder model than that was developed in our past experiment. © 2012 IEEE.

To determine the effects of a [6]-gingerol analogue (6G), a major chemical component of the ginger rhizome, and its stable analogue after digestion in simulated gastric fluid, aza-[6]-gingerol (A6G), on diet-induced body fat accumulation, we synthesized 6G and A6G. Mice were fed either a control regular rodent chow, a high-fat diet (HFD), or a HFD supplemented with 6G and A6G. Magnetic resonance imaging adiposity parameters of the 6G- and A6G-treated mice were compared with those of control mice. Supplementation with 6G and A6G significantly reduced body weight gain, fat accumulation, and circulating levels of insulin and leptin. The mRNA levels of sterol regulatory element-binding protein 1c (SREBP-1c) and acetyl-CoA carboxylase 1 in the liver were significantly lower in mice fed A6G than in HFD control mice. Our findings indicate that A6G, rather than 6G, enhances energy metabolism and reduces the extent of lipogenesis by downregulating SREBP-1c and its related molecules, which leads to the suppression of body fat accumulation.

Performing laparoscopic surgery requires several skills which have never been required for conventional open surgery, surgeons experience difficulties in learning and mastering these techniques. Various training methods and metrics have been developed in order to assess and improve surgeon's operative abilities. While these training metrics are currently widely being used, skill evaluation methods are still far from being objective in the regular laparoscopic skill education.
This paper proposes a methodology of defining a model to objectively evaluate surgical performance and skill expertise in the routine laparoscopic training course. Our approach is based on the processing of kinematic data describing the movements of surgeon's upper limbs. An ultra-miniaturized wearable motion capture system (Waseda Bioinstrumentation system WB-3), therefore, has been developed to measure and analyze these movements. The skill evaluation model was trained by using the subjects' motion features acquired from WB-3 system and further validated to classify the expertise levels of the subjects with different laparoscopic experience. An experiment for training fundamental laparoscopic psychomotor skill was elaborated by using laparoscopic box trainer. Preliminary results show that, the proposed methodology can be efficiently used both for quantitative assessment of surgical ability, and for the discrimination between expert surgeons and novices.

In recent years advanced robotic technology has seen more use in the medical field to assist in the development of efficient training systems. Such training systems must fulfill the following criteria: they must provide quantitative information, must simulate the real-world conditions of the task, and assure training effectiveness. We developed Waseda Kyotokagaku Airway series to fulfill all of those requirements. The WKA series we had developed does not consider external appearance such as patient skin, or internal appearance such as the pharynx, larynx, and esophagus. Moreover, the tongue mechanism of the previous system can not precisely measure the force applied by medical devices and cannot simulate muscle stiffness. In addition, the mandible mechanism of the previous system could not adequately reproduce various airway difficulties or apply force control. For these reasons, we propose the WKA-4, which has high-fidelity simulated human anatomy, and we have improved the mechanism over the previous system. We have also attached a lung to the proposed system to improve simulation of the real-world conditions of the task. In this paper, we present how to design several organs with various embedded sensors and actuators, for a conventional patient model with high-fidelity simulated human anatomy. We also present the control system for the WKA-4. Finally, we present a set of experiments carried out using doctors as subjects, and they gave their valuable opinions about our system.

:This paper presents the preliminary performance evaluation of our new wireless ultra-miniaturized inertial measurement unit (IMU) WB-4 by compared with the Vicon motion capture system. The WB-4 IMU primarily contains a mother board for motion sensing, a Bluetooth module for wireless data transmission with PC, and a Li-Polymer battery for power supply. The mother board is provided with a microcontroller and 9-axis inertial sensors (miniaturized MEMS accelerometer, gyroscope and magnetometer) to measure orientation. A quaternion-based extended Kalman filter (EKF) integrated with an R-Adaptive algorithm for automatic estimation of the measurement covariance matrix is implemented for the sensor fusion to retrieve the attitude. The experimental results showed that the wireless ultra-miniaturized WB-4 IMU could provide high accuracy performance at the angles of roll and pitch. The yaw angle which has reasonable performance needs to be further evaluated.

This paper presents the design and development of a bio-inspired mobile robot called WR-3 (Waseda Rat no. 3). The purpose of the robot is to work as an experimental tool to study social interaction between rats and robots. According to the results of the analysis of the motion of rats, their behavior can be divided into two phases: movement and interaction. Therefore, a novel hybrid mechanism that uses wheels during the movement phase and legs while interacting has been designed to actuate WR-3. Consequently, the robot can move at a high speed using its wheels, and reproduce the rat&apos;s interaction behavior using its legs and other parts. Based on body structure of a mature rat, WR-3 has been designed with similar dimensions and shape as a mature rat, and the quality of the shape imitation has been verified by the experiments of a rat&apos;s interestingness to the robot and stuffed rat. Evaluation experiments show that WR-3 is capable of reproducing a rat&apos;s actions such as chasing, rearing, grooming, mounting, etc., similar to a real rat. Furthermore, preliminary social interaction tests with living rats reveal that WR-3 is to some extent able to evoke natural reactions form a real rat and is therefore able to perform a certain level of realistic interaction. (C) Koninklijke Brill NV, Leiden and The Robotics Society of Japan, 2011

In the development of medical skill training systems, the efficiency of the system and the provision of quantitative feedback information to the trainee are very important. Furthermore, usage of the simulated operation platform should be as realistic as possible. In order to satisfy these requirements, we developed a robot to be used for airway management training: Waseda KyotoKagaku Airway No.1 Refined RII (WKA-1RII) (Fig. 1). In addition to realistically shaped hardware and various sensory equipments inside the robot, the new training system also uses a binocular vision system, an inertial measurement unit and a 3D simulation software component to track the movements of the trainee. For fully estimating the skills of the trainee and providing richer feedback, it is not enough to only use information about the tool's movements from the inside of the robot. Therefore, we propose a system to fuse the sensory information from inside the robot with data from 3d vision and from the inertial measurement unit. This accurate information about the movements of the trainee is used to model the progress of the training with a 3d computer graphics simulator. The trainee can use this visualization during or after the training procedure to verify his training status. Using this system he has the possibility to easily compare his performance with a guideline performance provided by an experienced surgeon. In this paper we show a first conceptual application of this approach. The experimental results lead to the consideration that the approach is worth following in further research. © 2011 IEEE.

:The training in the surgical practice is of paramount importance to prepare the residents in performing surgical procedures on human subject and to provide exercise on new techniques for experienced surgeons. Usually, these trainings are carried out on live animals or in virtual environments and dry boxes; the complexity of the exercises is identical in both of the case, but the pressure in operating with a living subject could change the attitude and the movements of the trainee. Until now, it has not been possible to analyze this stress in details together in the surgical animal training and dry boxes. In this work we propose an innovative portable system that can measure two physiological parameters, the heartbeat and the surface electromyography, during a session of training in both of the environment. The preliminary results, for one subject, show a bigger average power in the shoulder muscles during the living operation together with a higher but stable heartbeat rate.

The Simulation Model which can visualize the shape of commercial colonoscope is proposed. This model uses kinematic chain which approximates the shape of colonoscope by serially connected multiple joint-link pairs. As the input to the model, orientation information is used. Orientation information is extracted from the Sensor Network. The sensor network consists of connecting a number of sensor units with CAN bus. Each sensor unit also has two kinds of sensor: triad of accelerometer and triad of magnetometer. Roll and pitch angle are estimated based on the accelerometer signals. Yaw angle is estimated based on the magnetometer signals. By using kinematic chain model and orientation as input, we estimate the key points which are positions of sensor units on the colonoscope. Then, we implement spline interpolation to find the intermediate points which constitutes the shape of colonoscope. We made experiment in order to check whether model has enough accuracy. Firstly, we compared estimated curve with sine curve which is used as a ground truth. Secondly, we investigated the effect of number of sensor on the accuracy. Final result says that it has enough estimation ability.

The general characteristics of the colon are proposed in the mechanical point of view. This is prerequisite information when we want to develop endoscopic robot which can move well in the human colon. Friction property which comprise static and dynamic friction coefficient is investigated. The elastic property of colon is also investigated: the radial tensile force is measured in the elastic range. The effect on the robot is revealed by using experimental method. The design parameters of the robot are then investigated: one is for the moving mechanism which has to be selected in view of mobility compared to the above knowledge. The other is for selection problem on the fin type and size in the inverse screw type. Several apparatus for friction property measurements were made and carefully made experiments. The resulting data were analyzed. Final results show that inverse screw type of robot has more mobility compared to the rotational inertia type. © 2011 IEEE.

In this paper, the shape of the medical robot which can move in the colon is suggested for its gate control. In this system, the current shape information plays a sensing role in order to control the gate of robot in the colon. In order to find current shape of robot, we construct sensor network system which composed of several electronic compass units. This unit makes use of chip which includes pair of 3 axis accelerometer and 3 axis magnetometer. From this signals, orientation is evaluated after filtering noise. Then, based on the kinematic chain model, the shape of the flexible robot is calculated using orientation information. The resulting trajectory shows that this method cans percept shape of flexible robot well. © 2011 IEEE.

3D Visualization method of shape of flexible colonoscopy in simulated computing environment is proposed. Signals from sensor network are used to calculate the orientation of the body of each sensor. Position of each sensor is estimated from the orientation using assumption of forward kinematics in robotics. This data are then interpolated with curve fitting method to give natural impression of shape to surgeon who are watching monitor. The resulting simulated curve shows that motion of shape of colonoscopy can be simulated at it is.

This research proposes to design and develop a novel robot involved in the general and famous animal experimental method called Social Interaction Test (SIT). Aiming at increased movement range of the waist and improved interoperability, we have developed a novel small animaroid robot WR-4 (Waseda Rat No.4). The waist of WR-4 endowed with a multi-bendable 6-bar linkage mechanism makes the robot able to rotate around ±130° horizontally, meeting required movement range. Integrating with a 4-bar linkage mechanism in the neck, this 6-bar linkage mechanism achieves the bending posture as living rats, allowing the imitation of behavior such as rotating. Furthermore, ultrasonic motors (USM) used to drive forelegs greatly reduce the weight of upper body, resulting in quicker acting of rearing behavior. WR-4 consists of 10 active DOFs (two 1-DOF wheels for locomotion, two 2-DOF forelegs for interaction, one 1-DOF neck for swing, one 2-DOF waist for rearing and body grooming and one 1-DOF reserved for tail) and 2 passive DOFs in the paws. The evaluation tests on motion performance show that WR-4 could act both rearing (reaching 60°) and rotating (reaching ±100° respectively) behaviors approximately 0.1s quicker than mature rats. Preliminary SIT between WR-4 and mature rats have been conducted strictly following psychological rules. Experimental results reveal that the frequencies of rearing behavior in rats were increased significantly when WR-4 reared periodically, and the activities of rats were decreased after WR-4 reared. © 2011 IEEE.

Purpose Fibre optic colonoscopy is usually performed with manual introduction and advancement of the endoscope, but there is potential for a robot capable of locomoting autonomously from the rectum to the caecum. A prototype robot was designed and tested.
Methods The robot colonic endoscope consists in a front body with clockwise helical fin and a rear body with anticlockwise one, both connected via a DC motor. Input voltage is adjusted automatically by the robot, through the use of reinforcement learning, determining speed and direction (forward or backward).
Results Experiments were performed both in-vitro and in-vivo, showing the feasibility of the robot. The device is capable of moving in a slippery environment, and reinforcement learning algorithms such as Q-learning and SARSA can obtain better results than simply applying full tension to the robot.
Conclusions This self-propelled robotic endoscope has potential as an alternative to current fibre optic colonoscopy examination methods, especially with the addition of new sensors under development.

Robot Technology should contribute to the progress of other research fields. We'd like to propose one example of it. In psychology, basic medicine and biological science, several experiments on animal behavior have been performed to clarify brain functions or mechanisms of learning. These experiments have been playing very important role to understand human mind. Rats and mice have been well used in these experiments. Therefore, we have been developing quadruped robots that reproduce animal behavior as new experimental tools. We developed a quadruped robot that has 4 legs and reproduces some social behaviors. Each leg has 3 DOFs. The robot also has 2 DOF at the neck and 2 DOF at the waist.

Problem statement: Jaw movement analysis, as a clinical aid, can provide an objective basis for understanding and diagnosing jaw musculoskeletal disorders. Therefore, the use and development of devices for quantitatively measuring and analyzing jaw movement have become more common and popular in the clinic. Many types of jaw tracking devices have been developed, but most of them are still not handy and easy to be used. Approach: To improve the handiness and utility of the jaw movement analysis devices, we developed a simple to be used jaw tracking prototype by using a new ultra-miniaturized Inertial Measurement Unit (IMU) named WB-3. The WB-3 IMU was composed by 3-axis gyroscope, 3-axis accelerometer and 3-aixs magnetometer, which can not only measure the acceleration and angular speed of jaw movement, but also can measure mouth opening angle. The IMU's extremely reduced weight and size allowed it to be easily adhered to mandible during normal tests without physical restriction to the subjects. A preliminary experiment for jaw movement analysis during free chewing of three types of food with different shapes and hardness was evaluated. A group of 15 healthy subjects aged from 21-36 years old kindly participated in the experiment. Results: The parameters of chewing time, chewing frequency, power spectrum density of jaw's angular speed and acceleration, cumulative distribution function of jaw's acceleration and mouth opening angle were presented. The experimental results clearly showed that the subjects used less chewing time, less chewing frequency, less acceleration cumulative distribution and energy to eat soft food
higher values were found in the case of hard food and there was no significant difference in mouth opening angle while eating these three foods. Conclusion: Our jaw movement analysis prototype using IMU WB-3 was proved to be a valid and handy method for jaw movement and pattern analysis which may be used clinically as an assistant system for dental therapy. © 2010 Science Publications.

Real-time tracking of human body motion is an important technology in synthetic environments, robotics, and other human-computer interaction applications. This paper presents an ultra-miniaturized inertial measurement unit (IMU) named WB-3 for real-time attitude estimation of human limb segments. The WB-3 IMU is provided with a 32-bit microcontroller and 9-axis inertial sensors (miniaturized MEMS accelerometer, gyroscope and magnetometer). The quaternion-based Extended Kalman Filter (EKF) was implemented for the sensor fusion to retrieve the attitude of the human segment. An upper body motion capture system with 12 WB-3 IMUs was elaborated for tracking human movements in real time scenarios. ©2010 IEEE.

Mastication analysis can provide an objective basis for studying and diagnosing jaw musculoskeletal disorders. Therefore, the use and development of devices for quantitatively measuring and analyzing jaw movement have become very popular in the consulting room. This paper proposes a simple to be used jaw tracking prototype by using the new miniaturized wireless Inertial Measurement Unit (IMU) named WB-4. The WB-4 IMU primarily contains a mother board, a Bluetooth module and a Li-Polymer battery. The mother board is provided with a microcontroller and 9-axis inertial sensors (miniaturized MEMS accelerometer, gyroscope and magnetometer) to measure the jaw motion. The data transmission between WB-4 and PC is based on the Bluetooth module to realize the wireless communication. The IMU's extremely reduced weight and size allows it to be easily attached to mandible during normal mastication tests without physical restriction to the subjects. Three pilot experiments for mastication analysis of chewing gum were elaborated. A group of 9 healthy subjects kindly participated in the experiment. The preliminary results show that WB-4 IMU can efficiently evaluate the jaw movement and mastication pattern of different subjects, which could provide quantitative information to the doctors for the diagnosing and clinical treatment of different jaw diseases. ©2010 IEEE.

Purpose Oral disorders such as temporomandibular joint disorders (TMD) and dry mouth are common and often require treatment. Maxillofacial massage is used as a complementary and alternative therapy for these disorders. We developed an oral rehabilitation robot that massages the maxillofacial tissues for this purpose. In this paper, we propose a control system for oral rehabilitation robots.
Method The control system consists of a massage path generator, virtual compliance calculator, and inverse kinematics calculator. The massage path generator computes a target massage path based on a human head model obtained from a reference MRI image of an adult male. The head model includes the shape and elastic modulus of each component, all of which were obtained experimentally. Virtual compliance control is used to control manipulators with position servo actuators. The manipulators, which have a force sensor at their end-effectors, move actively in the direction of the external force applied to their sensors via virtual compliance control. We implemented this control in WAO-1, our first prototype oral rehabilitation robot.
Results WAO-1 provided massage to three adult male subjects with and without virtual compliance control. One of the subjects was the adult male whose MRI image was used to synthesize the head model in the massage path generator. Without virtual compliance control, the actual massage force was greater than the target massage force, while that with virtual compliance control was less than the target massage force. Furthermore, with virtual compliance control, the massage paths conformed to the head shape of each patient.
Conclusion Implementation of virtual compliance control in the WAO-1 massage robot is feasible and useful for implementation of safe and potentially effective maxillofacial massage therapy.

The number of patients with mental disorders is increasing in advanced countries. Many researchers are working to develop mental disorder model animals that contribute to development of new psychotropic drugs. However, we have some doubts about conventional mental disorder models. Therefore, the purpose of this study is to develop an experimental setup to create novel mental disorder model animals. We then developed a small mobile robot and a control system for the robot. Using them, we performed an experiment to develop a mental disorder model rat. In the experiment, we succeeded in developing a new depression model rat and also high activity model rat. These disorder models must be useful in the screening of new psychotropic drugs. In addition, the methodology we developed in this research will contribute to clarifying mechanisms of mental disorders.

The interaction experiment, between a robot and a rat, will benefit significantly when the rat's actions can be recognized automatically in real time. Regarding quantitative behavior analysis, the number and duration of a rat's actions should be measured efficiently and accurately. Therefore, aiming at the above-mentioned objectives, a novel cognition system capable of detecting rats' actions has been proposed in this paper. The main function of this cognition system lies on the real-time recognition and offline analysis of rats' behaviors. Basic image processing algorithm as Labeling and Contour Finding were employed to extract feature parameters (body length, body area, body radius, rotational angle, and ellipticity) of rat's actions. These parameters are integrated as the input feature vector of NN (Neural Network) and SVM (Support Vector Machine) training system respectively. Preliminary experiments reveal that the grooming, rotating and rearing actions could be recognized with extremely high rate (more than 90%) by both NN and SVM. Compared to NN, SVM provides better recognition rate and less computational cost. © 2010 IEEE.

This paper presents the design and development of a bio-inspired mobile robot called WR-3 (Waseda Rat No. 3), as an experimental tool to study social interaction between rats and robots. According to the motion analysis of rats, their motion can be divided into two phases: moving and interaction. Therefore, a novel hybrid mechanism in which wheels are used for moving and legs are used for interaction has been designed to actuate the WR-3. Consequently, the robot can move at a high speed using its wheels and reproduce the rats' interaction using its legs and other parts. Based on the dimension and body structure of a mature rat, WR-3 has been designed with dimensions of 240x70x90[mm] and is the same shape as a rat. It consists of 18 DOFs in total: two 1-DOF wheels, four 3-DOF legs (including passive DOFs), a 2-DOF waist, and a 2-DOF neck. Preliminary interaction experiments with rats demonstrate that WR-3 is capable of reproducing interactions such as following, rearing, grooming, mounting, etc. similar to a real rat.

In the domain of psychology and medical science, many experiments have been conducted referring to research on animal behaviors, to study the mechanism of mental disorders and to develop psychotropic drugs to treat them. Rodents such as rats are often chosen as experimental subjects in these experiments. However, according to some researchers, the experiments on social interactions using animals are poorly-reproducible. Therefore, we consider that the reproducibility of these experiments can be improved by using a robotic agent that interacts with an animal subject. We have developed a novel quadruped rat-inspired robot, the WR-2 (Waseda Rat No. 2), based on the dimension and body structure of a mature rat. It is capable of reproducing the behaviors such as walking, mounting, rearing and grooming of the rat.

We have developed an oral-rehabilitation robot WAO-1 (Waseda Asahi Oral-rehabilitation robot No. 1) for use in cases of oral disorders such as temperomandibular joint (TMJ) disorder and dry mouth. WAO-1 is the first robot designed to provide massage to the facial tissues of a patient with oral disorders. This robot provides massage to the masseter and temporal muscles and to the parotid gland and duct with simple operation. It consists of two six-degree-of-freedom arms with plungers, a body with headrest, a control box, a PC, and an automatic massage trajectory generation system with virtual compliance control. Two evaluation experiments were performed to verify the effectiveness of the oral massages of WAO-1 compared with the massages given by doctors. In the experiments, the massage to the parotid gland and duct by WAO-1 increased the amount of saliva in the subjects, and the massage to the masseter muscle by WAO-1 increased facial skin temperature and width of the masseter muscle in the subjects. We consider that these results indicate that massage by WAO-1 can be effective for patients with oral disorders.

This study determined suitable conditions for masseter and temporal muscle massage using a specially fabricated robot and evaluated its effects on patients with TMJ dysfunction associated with myofascial pain.
The robot was designed with two arms with six degrees-of-freedom, and equipped with plungers. A phase-1 trial examined 22 healthy volunteers to determine its safety and suitable massage pressure, examining three different pressures. The volunteers evaluated their comfort, warmth, and ease of mouth opening by use of a visual analogue scale (VAS). A phase-2 trial examined the safety, suitable dose regimen, and efficacy in 12 patients. Maximal mouth opening was measured, and muscle pain and massage were evaluated subjectively.
The robot was safe in the phase-1 trial, except for two massages in which the pressure was excessive. Massages at 6-10 N were given the highest VAS scores. In phase 2, the massage pressure was arbitrary and each muscle was massaged seven times for 1 min, three times every two weeks. After evaluating the efficacy, additional treatments were performed at a greater pressure or for longer. The massage treatment was very effective for most patients.
The massage treatment was safe and effective for most patients when administered at a pressure of 6-10 N seven times for 1 min per muscle every two weeks. The robot may constitute a useful tool for treating TMJ dysfunction associated with myofascial pain.

It is well known that the massage therapy is useful for the rehabilitation of various diseases (i.e. oral health problems, etc.). Although various apparatus have been developed for the massage of the torso and limbs, there is still little knowledge about their real effectiveness. For this purpose, authors have proposed the development of a robotic system that provides massage therapy of the maxillofacial region to patients with temporomandibular joint disorders. As a result of our research, we have developed the Waseda-Asahi Oral-Rehabilitation No.1 (WAO-1), which it is composed by two six-degrees of freedom arms with plungers attached at their end-effector. Preclinical tests were carried out to confirm the effectiveness of the proposed system. In order to evaluate the safety measures of the applied forces during the massage therapy, we have based our analysis on the Visual Analogue Scale (VAS) which is a conventional subjective evaluation methods commonly used in the medical field. From the experimental results, we could confirm the effectiveness of the therapy provided by WAO-1.

It is well known that the massage therapy is useful for the rehabilitation of various diseases (i.e. oral health problems, etc.). Although various apparatus have been developed for the massage of the torso and limbs, a machine to perform precise massage therapy to maxillofacial region is not developed yet. The ability of a robotic system to exert itself without fatigue aims in providing more hours of therapy per day, resulting in an increased number of patients that can be treated. This increased potential for treatment would benefit the elderly persons as well allowing more frequent treatments and more convenience in scheduling. For this purpose, the authors have developed the Oral-Rehabilitation Robot which provides massage of the maxillofacial region as a therapy to patients with temporomandibular joint disorders, etc. Then, we developed the Waseda-Asahi Oral-Rehabilitation Robot No.1 Refined (WAO-1R) by redesigning the arms of WAO-1 to increase variety of massage. By this improvement, the angular limitation of end-effector is increased from 60 degrees to 360 degrees. In order to assess the effectives of the massage provided by the robotics system, different performances indexes were proposed based on the medical literature and from our discussion with experts. A set of experiments were carried out to confirm if the mechanical improvements enhanced or not the effect of the massage provided by the WAO-1R. From the experimental results, we could detect increasing the thickness of masseter muscle on volunteers and the amount of mouth-opening after providing the massage with WAO-1R compared with the previous robot.

The emerging field of medical robotics aims to introduce intelligent tools to assist a physician. The main challenges for developing efficient medical robotic training systems are simulating real-world conditions of the task and assuring training effectiveness. High anatomic fidelity has been achieved in current systems. However, those training systems are designed to reproduce specific conditions of the task (passive training). In this research, we are focusing in developing an airway management training systems designed to reproduce various cases of difficult airway. Such difficulties (i.e. restricted mouth opening, various shapes of oral cavity including tongue swallowing, etc) may provoke traumas on different organs of the patient during an emergency situation. For this purpose, the authors have proposed the development of more advanced training tools. For this purpose, we have focused in embedding sensors and actuators to a conventional patient model towards the development of a patient robot (in previous research, authors have presented the evaluation model which embeds sensors). In this paper, we present an airway training system which embeds actuators into a mannequin. In particular, the mechanism design of the Waseda Kyotokagaku Airway No.2 (WKA-2) is detailed. The WKA-2 is composed of twelve active and one passive degrees of freedom; which are designed to reproduce the various cases of difficult airway. For this purpose, the WKA-2 reproduces the human muscles around the upper airway based on a wire driving mechanisms (a total of sixteen wires are used). In particular, the head of the model is composed of a tongue and mandible with translational and rotational movements around kinematic axis. In addition, we present the details of the kinematic model of WKA-2 which enable the robot to reproduce the airway difficulties. Finally, we presented the design of a tension sensor designed to measure the applied tension on each of the wire driving mechanism of WKA-2. As preliminary experiments, we reproduce several cases of difficult airways using WKA-2.

Up to now, different kinds of medical training systems have been developed which were designed to reproduce the human anatomy in high fidelity. However, these kinds of systems are limited to provide quantitative information of the trainees' operation, only provide subjective assessment to them, and finally to provide few feedbacks to them. Therefore, we would like to propose the advanced medical training method using RT which enables us to not only provide quantitative information of the trainees' operation, but also objective evaluation to them from the quantitative information. For the purpose of these facts, we developed Waseda Kyotokagaku Airway-No.1 Refined (WKA-1R) which embeds many sensors in order to provide quantitative information of the trainees' skill as well as an evaluation unit for them. However, the force sensor of WKA-1R has three problems, such as a limited measurement of the applied force, calibration, and maintenance for practicality. In this paper, we propose newly developed Tension/Compression Detection Sensor System (TCDSS) which not only reinforces calibration and maintenance for practicality, but also enables us to measure tension, compression, and torque. In addition, we also propose a Tactile Detection Sensor System (TDSS) which enables us to obtain the information of tactile sensation of the robot. Finally, preliminary experiments have been proposed to obtain the characteristic curve on the TCDSS.

Object The emerging field of medical robotics aims to introduce intelligent tools for physician support. The main challenges for developing efficient medical robotic training systems are simulating real-world conditions of the task and assuring training effectiveness. High anatomic fidelity has been achieved in current systems, but they are limited to provide merely subjective assessments of the training progress. We simulated airway intubation using a unique medical robot and developed objective performance criteria to assess task performance.
Materials and methods A patient simulation robot was designed to mimic real-world task conditions and provide objective assessments of training progress. The Waseda-Kyotokagaku Airway No. 1R (WKA-1R) includes a human patient model with embedded sensors. An evaluation function was developed for the WKA-1R to quantitatively assess task performance. The evaluation includes performance indices and coefficient weighting. The performance indices were defined based on experiments carried out with medical doctors and from information found in the medical literature. The performance indices are: intubation time, jaw opening, incisor teeth force, cuff pressure, tongue force and tube position. To determine the weighting of coefficients, we used discriminant analysis.
Results Experiments were carried out with volunteers to determine the effectiveness of the WKA-1R to quantitatively evaluate their performance while performing airway management. We asked subjects from different levels of expertise (from anesthetists to unskilled) to perform the task. From the experimental results, we determined operator effectiveness using the proposed performance indices. We found a significant difference between the experimental groups by evaluating their performances using the proposed evaluation function (P &lt; 0.05).
Conclusions The WKA-1R robot was designed to quantitatively acquire information on the performances of trainees during intubation procedures. From the experimental results, we could objectively determine operator effectiveness while providing quantitative task assessments.

Object Nowadays, most of the surgical training programs follow a duration-based format that focuses on improving technical skills of trainees for a fixed amount of time before declaring their proficiency. More recently, different approaches have been proposed for the skills assessment; such as the objective structured clinical examination (OSCE). The OSCE consists of different stations in which trainees are required to perform practical exams while their performance is evaluated by examiners. However, their performance cannot be easily assessed by the simple observation of the task. As a result, no standard evaluation criteria can be conceived.
Methods Thanks to the recent advances in Robot Technology (RT); more efficient training systems can be conceived. In particular, authors believe in the importance of developing automated training devices designed to provide training progress quantitative information of trainees. For this reason, at Waseda University, since 2004, we have proposed as a long-term research goal, the development of a Patient Robot which nearly reproduces the human body anatomy and physiology by embedding sensors and actuators into a human model. Due to the complexity of patient robot development, as a first approach, we have proposed the development of a Suture/Ligature Training System. In this paper, the details of Waseda-Kyotokagaku Suture No. 2 Refined II (WKS-2RII) are presented. The WKS-2RII has been designed to reproduce the task conditions of the suture and ligature as well as to provide quantitative information of artificial skin movement, and the physical properties of the suture. From such collected data, we have proposed an Evaluation Function that integrates all the proposed evaluation parameters.
Results In order to verify the effectiveness of the WKS-2RII, a set of experiments were proposed to analyze the performance of subjects while performing the task with the WKS-2RII. The experiments were designed to determine if the proposed system may provide more detailed information of the task in a quantitative way. From the experimental results, we have confirmed that the WKS-2RII is capable of providing quantitative assessment of the task. In contrast to the conventional training methods (i.e., OSCE, etc.), the WKS-2RII can provide more detailed information of the task performance, so that the proposed system can detect the differences among different level of expertise (five surgeons, five medical students and five unskilled persons) as well as detect improvements of trainees by plotting the learning curve.
Conclusions In this paper, we have presented the improvements on the WKS-2RII and a unique evaluation function has been proposed. Regarding the weighting coefficients, the discriminant analysis method was used to determine the optimal values of the weighting coefficients.

Up to now, there is no widely accepted quantitative evaluation scheme. Nowadays, an objective structured clinical examination has been proposed as a modern type of examination often used in medicine to test skills such as medical procedures, etc. The assessment of skills is realized by practical exams, in which students are evaluated by experienced examiner using a check list. However, the examiner lacks of information which cannot be obtained trough the simple observation of the task. Thanks to the recent advances in robot technology in embedded systems, etc.; more advanced evaluation tools can be conceived. For this reason, at Waseda University, we have proposed the development of a patient robot as an advanced evaluation tool to provide more detailed information of the task. As a first approach of our long-term research target, we have proposed the development of a suture/ligature training system which provides quantitative information of the movement of a dummy skin as well as information of the quality of task. In this paper; we describe the functionalities of the newest version, the Waseda-KyotoKagaku Skin No.2 Refined (WKS-2R), which has been designed to provide quantitative information of the task. In addition, we are proposing a new evaluation function which includes performance indexes and weighting coefficients. As a first approach, the weighting coefficients were determined by using the discriminant analysis. A set of experiments were proposed to confirm the effectiveness of the proposed evaluation function. From the preliminary results, the evaluation function was useful in detecting differences among different levels of expertise as well as detecting improvements during the training process by computing the learning curve.

We clarify the basic factors necessary for a symbiotic relationship between humans and robots. However, evaluating interaction between humans and robots is difficult due to a number of uncertain factors in human communication. Therefore, less sophisticated creatures, rats, were first selected, and we conducted interaction experiments between rats and robots. In our previous studies, we could not conduct these experiments for over 2 hours. We then developed a. new experimental system to conduct the experiments without time restrictions. Using this system, we conducted two interaction experiments. In one experiment, the robot, meeting a rat's request, could live symbiotically with the rat. In the other experiment, the robot, behaving sequentially without having met the rat, could control the rat. This paper investigates the factors for a symbiotic relationship between a rat and a robot by comparing the two experiments.