Journal of the Robotics Society of Japan
Online ISSN : 1884-7145
Print ISSN : 0289-1824
ISSN-L : 0289-1824
Volume 38, Issue 8
Displaying 1-11 of 11 articles from this issue
On special issue
  • Risa Ichimura, Hiroyuki Kajimoto, Makoto Shimojo, Aiguo Ming
    2020 Volume 38 Issue 8 Pages 737-745
    Published: 2020
    Released on J-STAGE: October 23, 2020
    Supplementary material

    This paper refers to a tele-grasping method by a multi-finger hand and an arm based on proximity-information feedback using sensors mounted on the fingertips of the hand. The sensors are composed of array of photo-reflectors connected in a network and can detect posture angles and distance between the finger and the object within a distance of several ten millimeters from the sensor. In this paper, we propose an electro-tactile stimulation method based on proximity sensor output for an operator to perceive intuitively the object when the hand approaches the object. According to the presentation of proximity information, we propose a strategy for tele-grasping and control method. An experimental system has been constructed and intentionally grasping of complex objects by the operator has been realized by the system.

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  • Takashi Kasai, Kazuya Okawa
    2020 Volume 38 Issue 8 Pages 746-753
    Published: 2020
    Released on J-STAGE: October 23, 2020

    In nature, various kinds of annimals especially insects use polarized light in the sky for navigation. In this paper, we propose a direction sensor using polarized light in the sky for outdoor mobile robot. The proposed method has two main characteristics.First, the method uses only one polarized light sensor although to my knowledge all conventional methods use more than one, which means the method doesn't need calibration between sensors. Secondly, we rotate polarizer at constant speed above a photodiode, and approximate output values with sinusoidal function, which enables the developed sensor less affected by noise and more accurate. The comparative experiment between the developed sensor and a gyro demonstrates the effectiveness of the proposed method. Lastly, controling mobile robot by the developed sensor, robot ran 20[m] straight with error of 0.13[m] sideways, which demonstrates the applicability of the developed sensor to mobile robot.

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  • Tetsuo Yoshimitsu, Takashi Kubota
    2020 Volume 38 Issue 8 Pages 754-761
    Published: 2020
    Released on J-STAGE: October 23, 2020

    Hayabusa2 is a Japanese asteroid explorer which aims to get some fragments from the C-type asteroid ``Ryugu'' and bring them back to the Earth. It was launched in December 2014 and arrived at the target asteroid at the end of June 2018 after 3.5 years' interplanetary cruise using an Ion engine propulsion system. The authors developed two tiny twin rovers for Hayabusa2 spacecraft. The objectives of the rovers were performing two technical experiments on the asteroid surface. They had hopping capability fitted for the microgravity environment of small planetary bodies, which was to be evaluated on the asteroid surface. The rovers had full autonomy to move to as many different places as possible and make some observations such as taking images and directly measuring the surface properties. The fully autonomous capability was to be demonstrated on the asteroid surface. The rovers were deployed onto the Northern hemisphere of the target asteroid on 04:06, 21 September 2018 (UTC) at the altitude of approximately 50 meters above the surface. Both rovers made autonomous surface explorations by hopping as planned, which were evidenced by the status and image data transmitted from the rovers. This was the World first surface mobile exploration on small planetary body in our Solar System attained by unmanned robot, as well as the first surface mobile exploration on extraterrestrial body in our country. This paper describes the technical aspects of MINERVA-II rovers, followed by some actual behaviors of the rovers on the asteroid surface which illustlated the great achievments of the two technical challenges by the rovers.

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