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Volume 51, Issue 6
Displaying 1-9 of 9 articles from this issue
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Special Issue on The 19th Robotics Symposia II
Paper
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Yu MUNAKATA, Masayoshi WADA2015 Volume 51 Issue 6 Pages 371-379
Published: 2015
Released on J-STAGE: June 13, 2015
JOURNAL FREE ACCESSIn this paper, we proposed a novel method for climbing over a step by a five-wheeled wheelchair with an active-caster drive wheel. A five-wheeled wheelchair is composed by attaching a single drive wheel on the back of a manual wheelchair. The relative position between the drive wheel and the wheelchair frame can be varied by the pin joint connection. This mechanism enables the wheelchair to perform a static wheelie motion. In this paper, the kinematics model of a static wheelie motion of the five-wheeled wheelchair was analyzed. Also by this kinematics model, the relativity between the attachment position of the drive wheel and the applied force for performing a static wheelie was examined. In some experiments, we confirmed the effectiveness of the kinematics model and the front casters of the wheelchair climb over a step by attaching the drive wheel according to the experimental results and simulations.View full abstractDownload PDF (1969K) -
Hiroki TOMORI, Suguru NAGAI, Tatsuo MAJIMA, Taro NAKAMURA2015 Volume 51 Issue 6 Pages 380-389
Published: 2015
Released on J-STAGE: June 13, 2015
JOURNAL FREE ACCESSHumans perform various motion such as jumping or throwing without high vibration, via variable viscoelasticity characteristics. On the other hand, highly rigid actuators such as geared motors or hydraulic actuators are widely used in industrial robots. It is difficult that they have variable viscoelasticity for them. In addition, to obtain high-speed motion, it is necessary to increase the actuator output as the robot weight increases. We have developed a one-degree-of-freedom manipulator with a variable rheological joint using a straight-fiber-type artificial muscle and a magnetorheological (MR) brake. With the generation of instantaneous force, the dead and rise times decreased compared to the conventional method. After the generation of an arbitrary instantaneous force, we controlled the robot's arm position by applying an equilibrium force on the joint. Furthermore, we controlled the vibrations of the arm by controlling the MR brake using an evaluation function. By this impedance control, response of the arm was improved without large loss of power.View full abstractDownload PDF (3509K) -
Yusuke GOUTSU, Takaki KOBAYASHI, Junya OBARA, Ikuo KUSAJIMA, Kazunari ...2015 Volume 51 Issue 6 Pages 390-399
Published: 2015
Released on J-STAGE: June 13, 2015
JOURNAL FREE ACCESSGesture recognition is used in many practical applications such as human-robot interaction, medical rehabilitation and sign language. With increasing motion sensor development, multiple data sources have become available, which leads to the rise of multi-modal gesture recognition. Since our previous approach to gesture recognition depends on a unimodal system, it was difficult to classify similar motion patterns. In order to solve this problem, a novel approach which integrates motion, audio and video models is proposed in the present paper by using dataset captured with Kinect. The proposed system can recognize observed gestures by using three models. Recognition results of three models are integrated by using the proposed framework and the output becomes the final result. The motion and audio models are constructed by using Hidden Markov Model. Random Forest which is the video classifier is used to learn the video model. In the experiments to test the performances of the proposed system, the motion and audio models most suitable for gesture recognition are chosen by varying feature vector and learning method. Additionally, the unimodal and multi-modal models are compared with respect to recognition accuracy. All the experiments are conducted on dataset provided by the competition organizer of MMGRC, which is a workshop for Multi-Modal Gesture Recognition Challenge. The comparison results show that the multi-modal model composed of three models scores the highest recognition rate. This improvement of recognition accuracy means that the complementary relationship among three models improves the accuracy of gesture recognition.View full abstractDownload PDF (2054K) -
—Development of a Transmission Mechanism and a Control Method for a Non-redundant Actuation System—Masayoshi WADA, Takahiro HIRAMA2015 Volume 51 Issue 6 Pages 400-408
Published: 2015
Released on J-STAGE: June 13, 2015
JOURNAL FREE ACCESSIn this paper, we propose a new type of omnidirectional mechanism which includes two balls as a transmitter of the power. The ACROBAT, we call the proposed system like this, is a caster type omnidirectional mechanism. The ACROBAT uses normal rubber tire, which is the different point from conventional omnidirectional robot. In order to determine the best construction of omnidirectional robot with ACROBATs, the efficiency of actuator usage is calculated in this paper. At last, computer simulation and experiments using a prototype are performed on the kinematics of the 3-wheeled robot. We confirm the possibility of ACROBAT system as a driving mechanism without special wheel, complicated control system, and sensing wheel orientation.View full abstractDownload PDF (2700K) -
Hitoshi KONO, Yuta MURATA, Akiya KAMIMURA, Kohji TOMITA, Tsuyoshi SUZU ...2015 Volume 51 Issue 6 Pages 409-420
Published: 2015
Released on J-STAGE: June 13, 2015
JOURNAL FREE ACCESSThis paper presents a framework of the hierarchical transfer learning (HTL) for a heterogeneous multi-robot transfer learning method utilizing of cloud-computing resources. A multi-agent robot system (MARS) that utilizes reinforcement learning and transfer learning methods has recently been deployed in real-world situations. In MARS, autonomous agents obtain behaviors autonomously through multi-agent reinforcement learning and the transfer learning method enables the reuse of the knowledge of other robots' behavior, such as for cooperative behavior. These methods, however, have not been fully and systematically discussed. In prior research, we developed an HTL method and investigated its effectiveness in a dynamic multi-agent environment. The HTL method hierarchically abstracts obtained knowledge by ontological methods. Here, we evaluate the effectiveness of HTL in heterogeneous multi-agent situation with action ontology by conducting a computer simulation.View full abstractDownload PDF (1523K) -
—Experiment of Radioactive Decontamination—Mitsuru ENDO, Mai ENDO, Takao KAKIZAKI2015 Volume 51 Issue 6 Pages 421-429
Published: 2015
Released on J-STAGE: June 13, 2015
JOURNAL FREE ACCESSThe Great East Japan Earthquake that occurred on March 11, 2011 resulted in the explosion of the TEPCO Fukushima 1st Nuclear Power Plant and the global dispersion of a large quantity of radioactive substances. A high radiation dose was particularly recorded in Fukushima prefecture several weeks after the accident, although the level is presently sufficiently low. However, considering that the adverse effects of low but extended exposure to radiation are yet to be negated, there is the urgent need for further decontamination. In our study, we focused on the efficient decontamination of radioactive substances in residential areas, for which we propose a high-pressure water jet system for washing road surfaces. The system differs from conventional systems of its type that were initially designed for use in the immediate environment of the nuclear reactors of the TEPCO Fukushima 1st Nuclear Power Plant. The proposed system consists of multiple washing, transporter, and server robots. The washing robots decontaminate the road surface using high-pressure water jets and are transported between washed and unwashed areas by the transporter robots. The server robots supply the water used for washing and absorb the polluted water together with ground dust. In this paper, we describe the concept of the system and present the results of decontamination experiments. Particular attention is given to the washing robot and its mechanism and control method. The results of the integration of the washing robot in an experimental system confirmed the feasibility of the proposed system.View full abstractDownload PDF (2508K)
Paper
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Hiroshi SUZUKI, Kazuma SEKIGUCHI, Mitsuji SAMPEI2015 Volume 51 Issue 6 Pages 430-439
Published: 2015
Released on J-STAGE: June 13, 2015
JOURNAL FREE ACCESSWe propose the novel controller design method for multi-input nonlinear systems based on the phase plane behavior. The controller is designed to minimize the difference of two vector fields : nonlinear closed-loop vector fields and stabilized closed-loop vector fields of linear approximation with linear controller. Stability of the proposed controller is guaranteed by considering the Lyapunov function on the phase plane. Furthermore, as application, we propose controlling methods based on evaluation functions. The effectiveness is illustrated by numerical simulation.View full abstractDownload PDF (2599K) -
Takuma TSUJI, Shunsuke HAMASAKI, Takaki MAEDA, Motoichiro KATO, Hiroyu ...2015 Volume 51 Issue 6 Pages 440-447
Published: 2015
Released on J-STAGE: June 13, 2015
JOURNAL FREE ACCESSRecently, the rubber hand illusion (RHI), which is one of phenomena that the sense of ownership (SOO) is extended to the objects over the external area, attracts much attention to explain the brain mechanism of self body recognition of human. However, most previous research have only focused on the conditions for the occurrence of the RHI. In this study, we measured electromyography (EMG) of the arm and skin conductance response (SCR) of the end of the finger when the strong hit with a hammer is given to the fake hand in order to examine whether the RHI is in fact occurred at a certain time during the experiment. As a result, we showed that the measurement of EMG could satisfy above requirement. Also, it is implied that the measurement of EMG gets closer to the same tendency of subject's introspection report than that of SCR.View full abstractDownload PDF (1428K)
Short Paper
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Taro TSUKAMOTO2015 Volume 51 Issue 6 Pages 448-450
Published: 2015
Released on J-STAGE: June 13, 2015
JOURNAL FREE ACCESSThis paper proposes a simple approach for probabilistic classification problem. Using kernels with random width as basis for logistic regression, and applying automatic relevance determination (ARD) technique, conditional density is estimated nether with cross-validation, nor with gradient-based adaptive parameter tuning.View full abstractDownload PDF (303K)
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