著者

Yuichi Kurita Takumi Okumura Ryota Imai Tomohiko Nishigami So Tanaka Takanori Taniguchi

出版者

Fuji Technology Press Ltd.

雑誌

Journal of Robotics and Mechatronics (ISSN:09153942)

巻号頁・発行日

vol.35, no.3, pp.612-621, 2023-06-20 (Released:2023-06-20)

参考文献数

31

---

Total knee arthroplasty (TKA) is the primary treatment for knee osteoarthritis. However, TKA is highly likely to result in prolonged chronic postoperative pain. The one-foot-one-step walking style is likely to induce fear of movement because of pain, leading to catastrophic thinking about the actual activity and consequently limiting movement. The aim of this study is to develop a system to induce the sensation of stair climbing through the interaction of the visual and kinesthetic senses. By controlling the amount of movement of the foot and the point of view in virtual space, the system can present a visual image of stair climbing even when the patient steps in a fixed position. This system enables easy motor imagery intervention even for early postoperative patients who have difficulty with the actual stair climbing movement. The clinical intervention experiment confirmed that the smoothness of the knee joint motion during descent was improved by intervening with motor imagery during stair ascent and descent for TKA patients.

著者

Koki Aoki Tomoya Sato Eijiro Takeuchi Yoshiki Ninomiya Junichi Meguro

出版者

Fuji Technology Press Ltd.

雑誌

Journal of Robotics and Mechatronics (ISSN:09153942)

巻号頁・発行日

vol.35, no.2, pp.435-444, 2023-04-20 (Released:2023-04-20)

参考文献数

23

被引用文献数

3

---

To realize autonomous vehicle safety, it is important to accurately estimate the vehicle’s pose. As one of the localization techniques, 3D point cloud registration is commonly used. However, pose errors are likely to occur when there are few features in the surrounding environment. Although many studies have been conducted on estimating error distribution of 3D point cloud registration, the real environment is not reflected. This paper presents real-time error covariance estimation in 3D point cloud registration according to the surrounding environment. The proposed method provides multiple initial poses for iterative optimization in the registration method. Using converged poses in multiple searches, the error covariance reflecting the real environment is obtained. However, the initial poses were limited to directions in which the pose error was likely to occur. Hence, the limited search efficiently determined local optima of the registration. In addition, the process was conducted within 10 Hz, which is laser imaging detection and ranging (LiDAR) period; however, the execution time exceeded 100 ms in some places. Therefore, further improvement is necessary.

著者

Ai Higuchi Junichiro Shiraishi Yuichi Kurita Tomohiro Shibata

出版者

Fuji Technology Press Ltd.

雑誌

Journal of Robotics and Mechatronics (ISSN:09153942)

巻号頁・発行日

vol.32, no.4, pp.798-811, 2020-08-20 (Released:2020-08-20)

参考文献数

28

被引用文献数

4

---

Parkinson’s disease (PD) is a common progressive neurodegenerative disease that affects a wide range of motor and non-motor symptoms. Freezing of gait (FOG) is such a motor symptom of PD that frequently results in falling, and almost half of PD patients suffer from FOG. In this study, we investigated the effectiveness of a robotic assistance system called UPS-PD, which was developed to suppress FOG. The double limb support phase (DLS) in a 10-m straight-line walking task, the gait time and step counts were measured in five PD subjects. In addition, the safety of the UPS-PD in a healthy person was investigated using OpenSim, and the DLS parameters in four healthy elderly subjects were evaluated. In the experiment with the PD patients, the DLS parameters of two subjects showed an improvement. Furthermore, the step length of one subject and the step length and walking speed of the other subject were improved. Moreover, there were no problems in terms of instability of gait in both the PD patients. The UPS-PD did not adversely affect the gait of healthy elderly subjects and the walking of a healthy subject model in the simulation. Therefore, the UPS-PD is considered to be a useful device for improving walking in PD patients.

著者

Kaito Sato Kenji Sawada

出版者

Fuji Technology Press Ltd.

雑誌

Journal of Robotics and Mechatronics (ISSN:09153942)

巻号頁・発行日

vol.35, no.2, pp.298-307, 2023-04-20 (Released:2023-04-20)

参考文献数

21

被引用文献数

1

---

In vehicle control, state estimation is essential even as the sensor accuracy improves with technological development. One of the vehicle estimation methods is receding-horizon estimation (RHE), which uses a past series of the measured state and input of the plant, and determines the estimated states based on linear or quadratic programming. It is known that RHE can estimate the vehicular state to which the extended Kalman filter cannot be applied owing to modeling errors. This study proposes a new computational form of the RHE based on primal-dual dynamics. The proposed form is expressed by a dynamic system; therefore, we can consider the computational stability based on the dynamic system theory. In this study, we propose a continuous-time representation of the RHE algorithm and redundant filters to improve the convergence performance of the estimation and demonstrate its effectiveness through a vehicle path-following control problem.

著者

Masahiko Inami Hiroyasu Iwata Minao Kukita Yuichi Kurita Kouta Minamizawa Masaaki Mochimaru Takuji Narumi Junichi Rekimoto Kenji Suzuki

出版者

Fuji Technology Press Ltd.

雑誌

Journal of Robotics and Mechatronics (ISSN:09153942)

巻号頁・発行日

vol.33, no.5, pp.985-986, 2021-10-20 (Released:2021-10-20)

---

Information technologies, such as IoT, artificial intelligence (AI), and virtual reality (VR), have seen so much development that there is now a wide variety of digital equipment incorporated into the infrastructure of daily life. From the agrarian society (Society 1.0) through the information society (Society 4.0), humankind has created farmlands and cities by structuring natural environments physically and has built information environments by structuring them informationally. However, despite the rapid development of information environments, it may be fair to say that the perspectives of the human body have not changed at all since the industrial revolution.In the context of these recent technological developments, greater attention is being paid to human augmentation studies. These studies aim for a new embodiment of “human-computer integration,” one which can physically and informationally compensate or augment our innate sensory functions, motor functions, and intellectual processing functions by using digital equipment and information systems at will, as if they were our hands and feet. It has also been proposed that the technical systems that enable us to freely do what we want by utilizing human augmentations be called “JIZAI” (freedomization) as opposed to “automation.”The term “JIZAI body” used in these studies represents the new body image of humans who will utilize engineering and informatics technologies to act at will in the upcoming “super smart society” or “Society 5.0.” In these studies, human augmentation technologies are an important component of JIZAI, but JIZAI is not the same as human augmentation. JIZAI is different in scope from human augmentation, as it aims to enable humans to move freely among the five new human body images: “strengthened sense” (augmented perception), “strengthened physical body” (body augmentation), “separately-designed mind and body” (out of body transform), “shadow cloning,” and “assembling.” In the society of the future where JIZAI bodies widely prevail, we will use technologies that enable us to do what we have failed at or given up due to limitations of our physical bodies. We believe that a future society, one in which aging does not reduce our capabilities but instead increased options give us hope, can be realized. This special issue, consisting of two review papers and twelve research papers, deals with diverse and wide-ranging areas, including human augmentation, robotics, virtual reality, and others. We would like to express our sincere appreciation to all the authors and reviewers of the papers contributed to this special issue and to the editorial committee of the Journal of Robotics and Mechatronics for their gracious cooperation.

著者

Masaru Ito Yusuke Funahara Seiji Saiki Yoichiro Yamazaki Yuichi Kurita

出版者

Fuji Technology Press Ltd.

雑誌

Journal of Robotics and Mechatronics (ISSN:09153942)

巻号頁・発行日

vol.31, no.2, pp.231-239, 2019-04-20 (Released:2019-04-20)

参考文献数

15

被引用文献数

12

---

Japan’s construction industry has a shortage of workers and skilled operators, and the number of operators of hydraulic excavators has actually been decreasing. In addition, the operation of hydraulic excavators is complicated and non-intuitive, so learning and maintaining the skill requires a considerable amount of time and experience. One technology that could solve this problem is the tele-operated hydraulic excavator, but the most common type of tele-operated system is difficult for ordinary hydraulic excavator operators to use. The introduction of operation simulators would be effective, but simulators have to be large and expensive if the interface is reproduced in life size. In this paper, we propose a cross-platform system for operating not only a tele-operated hydraulic excavator but also a hydraulic excavator operation simulator. The cross-platform system uses a tele-operated cockpit with feedback and an interface that gives the operator the sensation of sitting in an actual hydraulic excavator. The cockpit consists of a three-dimensional visual information system using stereo videos and a head mounted display, a motion simulator seat that reproduces the vibration and tilting of the operator’s seat of a hydraulic excavator, and a lever unit used in actual hydraulic excavators. With the cross-platform system, an actual hydraulic excavator can be remotely controlled, and the same cockpit can also be used as a training simulator. One can therefore use the system as an inexpensive means of acquiring and maintaining operation skills. We have successfully produced this proposed system and checked its functions, confirming that it works practically.

著者

Hiroki Endo Takashi Umeno

出版者

Fuji Technology Press Ltd.

雑誌

Journal of Robotics and Mechatronics (ISSN:09153942)

巻号頁・発行日

vol.29, no.4, pp.767-771, 2017-08-20 (Released:2018-11-20)

参考文献数

17

被引用文献数

5

---

This paper reported the tensile strength of the difference of modeling condition on the FDM (Fused Deposition Modeling) 3D printer. The FDM 3D printer is rapidly spread with the end of patent protection in 2009. The FDM models mainly use the prototyping part and art, because that models have low strength. This time we paid attention to that actual models weight is lighter than designing models weight to conduct study on strength. And we investigated the cause of the phenomenon of decrease of polymer extrusion by replacing with the injection molding method. The tensile test proved that the strength of model can be improved by the kind of extruder head. This paper reported influence of the cooling in the supply part of extruder head and temperature of the polymer on the strength of FDM 3D models.

著者

Hajime Mushiake

出版者

Fuji Technology Press Ltd.

雑誌

Journal of Robotics and Mechatronics (ISSN:09153942)

巻号頁・発行日

vol.34, no.4, pp.710-717, 2022-08-20 (Released:2022-08-20)

参考文献数

63

被引用文献数

1

---

Allostasis is a physiological principle based on a dynamic regulatory system, contrary to homeostasis, in which the goal is to reach a steady state and recover from deviation from a set point in the internal environment. The concept of allostasis has continued to develop with advances in the field of neuroscience. In this short review, the author presents several new findings in neuroscience and extend the concept of allostasis as mutual regulation between cognitive, somatic, and autonomic systems. In this manner, biological systems adapt to external and internal environments by changing themselves.

著者

Hirokazu Yamagata Shuma Kochii Hiroshi Yoshida Yoshifumi Nogi Toshihiro Maki

出版者

Fuji Technology Press Ltd.

雑誌

Journal of Robotics and Mechatronics (ISSN:09153942)

巻号頁・発行日

vol.33, no.6, pp.1223-1233, 2021-12-20 (Released:2021-12-20)

参考文献数

22

被引用文献数

3

---

The melting of ice and changes in ocean currents in Antarctica must be investigated to understand global climate change. In this regard, the volume changes of sea ice and ice shelves, bathymetry, and ocean currents in the Antarctic Ocean must be measured in three dimensions. Therefore, the use of autonomous underwater vehicles (AUVs), which can directly observe under ice, is being considered. The authors developed an AUV named Mobility Oriented Nadir AntarctiC Adventurer (MONACA) to observe sea ice and the lower region of the ice shelf in the Antarctic Ocean. Herein, we describe MONACA and its basic autonomous navigation methods (altitude control, depth control, and waypoint tracking), as well as report the results of a sea experiment conducted in Shimoda Bay, Japan. During the 5-day sea trial, the MONACA successfully measured bathymetry by tracking 15 waypoints in sequence, switching the control criteria in the -axis direction between 3 m depth and 3 m altitude.

著者

Koichiro Tadokoro Shotaro Fukuda Akio Namiki

出版者

Fuji Technology Press Ltd.

雑誌

Journal of Robotics and Mechatronics (ISSN:09153942)

巻号頁・発行日

vol.34, no.5, pp.956-964, 2022-10-20 (Released:2022-10-20)

参考文献数

24

被引用文献数

2

---

Our research group has developed an air hockey robot with high-speed vision capable of visual recognition at 500 Hz, which exceeds that of humans. Although this robot uses high-speed vision to increase its reaction speed and improve its performance, it has a low speed to compete with humans because its hand speed is still not sufficiently fast. In this study, a high-speed wrist rotation mechanism using a direct drive motor was introduced to the air hockey robot to improve the hitting speed through the snapping motion of the wrist. Furthermore, we developed a hitting motion algorithm that utilizes high-speed visual feedback. The effectiveness of the proposed system was verified experimentally. The proposed system exhibits an improved motion performance.

著者

Yumeta Seki Yu Kuwajima Hiroki Shigemune Yuhei Yamada Shingo Maeda

出版者

Fuji Technology Press Ltd.

雑誌

Journal of Robotics and Mechatronics (ISSN:09153942)

巻号頁・発行日

vol.32, no.5, pp.939-946, 2020-10-20 (Released:2020-10-20)

参考文献数

29

被引用文献数

19

---

Soft robots have great potential to realize machines that interact and coexist with humans. A key technology to realize soft robots is soft fluidic actuators. Previously, we developed a soft pump using the electrohydrodynamics (EHD) phenomenon. EHD is a flow phenomenon, which is generated by applying a high voltage to a dielectric fluid. In this study, we developed flexible high-power-density EHD pumps. First, a pump was fabricated by a simple design with interdigitated electrodes. Second, a mathematical model was used to analyze the pressure generated per length assuming that electric fields only act between neighboring electrodes in a flexible EHD pump with interdigitated electrodes. The results were used to optimize the gap between electrodes to maximize the pressure per length. Third, we used the optimized process to fabricate multiple flexible EHD pumps. The procedure produced pumps easily and reliably. Fourth, we compared the experimental values with the analytical solutions. The good agreement confirmed that the generated pressure per unit length can be approximated in a uniform electric field between neighboring electrodes. Because our flexible EHD pump can operate even when deformed, it has potential for wearable device applications.

著者

Komizunai Shunsuke Nishizaki Keisuke Wada Kyohei Kijima Takuya Konno Atsushi

出版者

Fuji Technology Press

雑誌

Journal of robotics and mechatronics (ISSN:09153942)

巻号頁・発行日

vol.28, no.6, pp.790-798, 2016-12

著者

Seo Takeda Tomohiro Umetani

出版者

Fuji Technology Press Ltd.

雑誌

Journal of Robotics and Mechatronics (ISSN:09153942)

巻号頁・発行日

vol.35, no.2, pp.380-386, 2023-04-20 (Released:2023-04-20)

参考文献数

19

被引用文献数

1

---

This study proposes a method for estimating the initial position of a mobile robot during a mobile robot experiment using expansion resetting. Depending on the type of sensor attached to the robot and the robot position and orientation estimation method, many operations may be required to estimate the initial position of the robot during an experimental run. The proposed method reduces the time and manual operations required to estimate the initial position and orientation of a mobile robot. The implementation of the method and its experimental results demonstrated the feasibility and effectiveness of the procedure.

著者

Kenta Suzuki Kuniaki Kawabata

出版者

Fuji Technology Press Ltd.

雑誌

Journal of Robotics and Mechatronics (ISSN:09153942)

巻号頁・発行日

vol.32, no.6, pp.1292-1300, 2020-12-20 (Released:2020-12-20)

参考文献数

11

被引用文献数

11

---

This paper describes the development of a robot simulator for remote decommissioning tasks using remotely operated robots at the Fukushima Daiichi Nuclear Power Station of the Tokyo Electric Power Company Holdings. The robot simulator was developed to provide a remote operation training environment to ensure operator proficiency. The developed simulator allows for the calculation of physical aspects, such as the hydrodynamics of a remotely operated vehicle and the aerodynamics of an unmanned aerial vehicle. A disturbed camera view presented to an operator can be generated by setting parameters such as transparency, color, distortion, and noise. We implemented a communication failure emulator on the simulator in addition to functionalities for calculating the integral dose and generating the gamma camera image. We discuss the functional requirements and introduce the implemented functionalities. The simulator was built using the developed functions and can be executed integrally.

著者

Yunfan Li Yukai Gong Jyun-Rong Zhuang Junyan Yang Keisuke Osawa Kei Nakagawa Hee-hyol Lee Louis Yuge Eiichiro Tanaka

出版者

Fuji Technology Press Ltd.

雑誌

Journal of Robotics and Mechatronics (ISSN:09153942)

巻号頁・発行日

vol.34, no.6, pp.1383-1397, 2022-12-20 (Released:2022-12-20)

参考文献数

32

被引用文献数

6

---

The world’s aging population is increasing. The number of elderly individuals having walking impairments is also increasing. Adequate exercise is becoming necessary for them. Therefore, several walking assistive devices have been developed or are under development. However, elderly individuals may have low motivation for exercising, or they may experience physical damage by excessive fatigue. This study proposed a method to enable elderly individuals to exercise with a positive emotion and prevent damage such as muscle fatigue. We proposed a 3D human condition model to control the walking assistive device. It includes the arousal, pleasure, and fatigue dimensions. With regard to the arousal and pleasure dimensions, we used heartbeat and electromyography (EEG) signals to train a deep neural network (DNN) model to identify human emotions. For fatigue detection, we proposed a method based on near-infrared spectroscopy (NIRS) to detect muscle fatigue. All the sensors are portable. This implies that it can be used for outdoor activities. Then, we proposed a walking strategy based on a 3D human condition model to control the walking assistive device. Finally, we tested the effectiveness of the automatic control system. The wearing of the walking assistive device and implementation of the walking strategy can delay the fatigue time by approximately 24% and increase the walking distance by approximately 16%. In addition, we succeeded in visualizing the distribution of emotion during each walking method variation. It was verified that the walking strategy can improve the mental condition of a user to a certain extent. These results showed the effectiveness of the proposed system. It could help elderlies maintain higher levels of motivation and prevent muscle damage by walking exercise, using the walking assistive device.

著者

Nobutsuna Endo Yuta Kizaki Norihiro Kamamichi

出版者

Fuji Technology Press Ltd.

雑誌

Journal of Robotics and Mechatronics (ISSN:09153942)

巻号頁・発行日

vol.32, no.5, pp.894-902, 2020-10-20 (Released:2020-10-20)

参考文献数

16

被引用文献数

12

---

There are not many physical models of oral and laryngeal systems for human speech movement in both computer simulators and mechanical simulators. In particular, there is no robot tongue mechanism that completely reproduces the deformation motion of the human tongue. The human tongue is an aggregate of muscles devoid of a skeleton. It only possesses a small hyoid. The purpose of this study is to develop a flexible actuator without a rigid link, aiming at the development of a tongue mechanism for a mechanical speech robot. We propose a flexible pneumatic bending actuator using thin McKibben muscles and a soft body formed by a silicone resin. We have verified its mechanical characteristics and described a control method for displacement and curvature. The elasticity/compliance of the silicone resin forming the soft body of this actuator was quantified by tensile tests. The oscillation parameters were identified, and it is suggested that the dynamic model can be described by a spring-mass-damper system. Assuming an arc-shaped deformation model, a simultaneous control system for the arc length and curvature was constructed and its effectiveness was confirmed.

著者

Keita Abe Yumeta Seki Yu Kuwajima Ayato Minaminosono Shingo Maeda Hiroki Shigemune

出版者

Fuji Technology Press Ltd.

雑誌

Journal of Robotics and Mechatronics (ISSN:09153942)

巻号頁・発行日

vol.34, no.2, pp.351-360, 2022-04-20 (Released:2022-04-20)

参考文献数

29

---

In recent years, untethered soft robots, free of the lines that restrict their mobility, have been studied extensively. Our research team has been focusing on the electrohydrodynamic phenomena (EHD) as a driving mechanism for untethered robots. EHD is a phenomenon in which a flow is generated by applying a high voltage to a dielectric liquid. We propose a method to drive a robot in an untethered manner using EHD by vertically stacking two types of liquids: conductive and dielectric. This method is simpler, more energy-efficient, and quieter than conventional systems. Although a lower voltage would prevent the enlargement of the system by limiting the electronic components, the generation of EHD requires a high voltage. Therefore, in this study, to realize the low voltage drive of untethered robots dominated by the electrostatic actuator, we tackled the reduction of the driving voltage by investigating the phenomenon. As a result, we achieved low voltage driving at 15 V and successfully drove with off-the-shelf batteries (18 V). We also investigated the output current flowing through the system to reduce power consumption. Therefore, in addition to improving the energy efficiency of the system, we confirmed that the difference of the generated current depended on the thickness of the dielectric liquid and the concentration of the conductive liquid.

著者

Inami Masahiko Iwata Hiroyasu Kukita Minao Kurita Yuichi Minamizawa Kouta Mochimaru Masaaki Narumi Takuji Rekimoto Junichi Suzuki Kenji

出版者

富士技術出版株式会社

雑誌

Journal of Robotics and Mechatronics (ISSN:09153942)

巻号頁・発行日

vol.33, no.5, pp.985-986, 2021

---

<p>Information technologies, such as IoT, artificial intelligence (AI), and virtual reality (VR), have seen so much development that there is now a wide variety of digital equipment incorporated into the infrastructure of daily life. From the agrarian society (Society 1.0) through the information society (Society 4.0), humankind has created farmlands and cities by structuring natural environments physically and has built information environments by structuring them informationally. However, despite the rapid development of information environments, it may be fair to say that the perspectives of the human body have not changed at all since the industrial revolution.</p><p>In the context of these recent technological developments, greater attention is being paid to human augmentation studies. These studies aim for a new embodiment of "human-computer integration," one which can physically and informationally compensate or augment our innate sensory functions, motor functions, and intellectual processing functions by using digital equipment and information systems at will, as if they were our hands and feet. It has also been proposed that the technical systems that enable us to freely do what we want by utilizing human augmentations be called "JIZAI" (freedomization) as opposed to "automation."</p><p>The term "JIZAI body" used in these studies represents the new body image of humans who will utilize engineering and informatics technologies to act at will in the upcoming "super smart society" or "Society 5.0." In these studies, human augmentation technologies are an important component of JIZAI, but JIZAI is not the same as human augmentation. JIZAI is different in scope from human augmentation, as it aims to enable humans to move freely among the five new human body images: "strengthened sense" (augmented perception), "strengthened physical body" (body augmentation), "separately-designed mind and body" (out of body transform), "shadow cloning," and "assembling." In the society of the future where JIZAI bodies widely prevail, we will use technologies that enable us to do what we have failed at or given up due to limitations of our physical bodies. We believe that a future society, one in which aging does not reduce our capabilities but instead increased options give us hope, can be realized. This special issue, consisting of two review papers and twelve research papers, deals with diverse and wide-ranging areas, including human augmentation, robotics, virtual reality, and others. We would like to express our sincere appreciation to all the authors and reviewers of the papers contributed to this special issue and to the editorial committee of the Journal of Robotics and Mechatronics for their gracious cooperation.</p>

著者

Ryota Murakami Takumi Toyoshima Daichi Furusawa Masaru Suzuki Kazunari Masumoto Sho Owada Yuichi Tsumaki Kyoichi Mori

出版者

Fuji Technology Press Ltd.

雑誌

Journal of Robotics and Mechatronics (ISSN:09153942)

巻号頁・発行日

vol.33, no.3, pp.475-483, 2021-06-20 (Released:2021-06-20)

参考文献数

16

被引用文献数

3

---

The biologging approach of attaching a logger to the body of an animal provides information that cannot be obtained by conventional direct visual observation. Marine zoologists have used this technique for observing sperm whales preying on giant squids in the deep sea. However, it is almost impossible to capture a sperm whale to attach a logger, because of its large size. Therefore, researchers have used a long pole to attach a logger from a ship to the back of sperm whales. Unfortunately, this method is risky and requires a skilled team. In this paper, we propose a logger attaching system using a drone to solve this problem. The proposed method can be trained on land; thus, it is relatively easy to train a team, and the mobility of the drone can shorten the installation time. Several pieces of equipment developed for the proposed method are described in detail. Furthermore, field experiments were performed with sperm whales to confirm the feasibility of the system. A suction cup of the seventh prototype of the whale rover was adsorbed onto the back of a sperm whale. Although a complete installation was not possible, it was demonstrated that operation was possible in a short time using the proposed method.

著者

Nakagawa Kayako Matsumura Reo Shiomi Masahiro

出版者

富士技術出版株式会社

雑誌

Journal of Robotics and Mechatronics (ISSN:09153942)

巻号頁・発行日

vol.32, no.1, pp.86-96, 2020

被引用文献数

4

---

<p>This paper focuses on "play-biting" as a touch communication method used by robots. We investigated an appropriate play-biting behavior and its effect on interaction. The touching action has positive effects in human-robot interactions. However, as biting is a defenseless act, it may cause a negative effect as well. Therefore, we first examine biting manner and the appearance of the robot using a virtual play-biting system in Experiment 1. Next, based on the result of experiment, the play-biting system is implemented in a stuffed animal robot. We verified the impressions created by the robot and its effect on mitigating stress in Experiment 2. Consequently, the play-biting communication gave positive and lively impression, and effect of reducing the physiological index of stress, in comparison to only touching the robot.</p>