Journal of the Robotics Society of Japan
Online ISSN : 1884-7145
Print ISSN : 0289-1824
ISSN-L : 0289-1824
Volume 5, Issue 4
Displaying 1-14 of 14 articles from this issue
  • Teruyuki IZUMI, Tatsuo NARIKIYO
    1987 Volume 5 Issue 4 Pages 255-262
    Published: August 15, 1987
    Released on J-STAGE: August 25, 2010
    JOURNAL FREE ACCESS
    On a grinding robot, it is very bothersome task to teach the contour of a workpiece accurately. Therefore, a teachingless grinding robot has been proposed by the authors. This robot system measures three components of moment which is given by a grinding force at the wrist of a manipulator, calculates grinding points on a cylindrical grinding wheel, and recognizes the contour of the workpiece.
    In order to develop this technique, this paper studies the method to calculate the grinding points on grinding wheels of various shapes. Results of analysis and experiments show the followings. 1) If the shape of a grinding wheel is known and constant without wearing away, the grinding points are able to be calculated from only three components of moment given by a grinding force. 2) The calculation is, however, very difficult when a radius of the grinding wheel is not linear function of the axis direction. Therefore, one component of a thrust has to be given to simplify the calculation. 3) Even if the shape of a grinding wheel is not known or varied by wearing away, the grinding points can also be calculated by measuring three components of a thrust in addition to the three components of moment.
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  • Koichi KONDO, Fumihiko KIMURA
    1987 Volume 5 Issue 4 Pages 263-272
    Published: August 15, 1987
    Released on J-STAGE: August 25, 2010
    JOURNAL FREE ACCESS
    This paper describes a general and simple method of planning collision-free paths of manipulators.
    Many off-line programming systems for industrial robots are developed to achieve high flexibility of manufacturing systems, but these systems are not powerful enough to cope with complex tasks. In order to realize more powerful programming system, it is indispensable to achieve the ability to automatically avoid collisions with obstacles in the working environment of manipulators. Many algorithms for the collision avoidance problem have been proposed, but no general and simple method is developed, which is applicable to any kind of manipulators.
    The method based on configuration space approach seems promising, but the configuration space is a multi-dimensional space and the amount of data of free space is enormous. However, most of these data is not used to plan a single motion of a manipulator. With the method based on Lee's algorithm, the free space that may be used to plan a motion can be determined independently of kinematic characteristics of manipulators. Therefore, it is possible to detect collisions at every con-figuration of manipulators. The algorithm of determining free space is as follows. First, collisions are detected during a linear movement in the configuration space and the set of collision-free configurations during this movement is calculated. Then, neighboring configurations are checked whether collision-free or not. Free space is determined in this way like a spreading wave front on a water surface. This process is continued until the wave front from an initial configuration and the one from a final configuration meet together.
    This method is implemented on a solid-model based robot programming system, and is applied to an articulated robot manipulator.
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  • —Design of Pressure Control Systems and its Consideration—
    Ichiro KIMURA, Toshi TAKAMORI, Yoshihide YASUDA, Yoshio MURAO, Youichi ...
    1987 Volume 5 Issue 4 Pages 273-282
    Published: August 15, 1987
    Released on J-STAGE: August 25, 2010
    JOURNAL FREE ACCESS
    This paper presents a new robot actuator using LaNi4, 5Al0.5 as metal hydride. It is a force output type actuator consisting of a heater, a metal hydride container, and a bellows. The metal hydride has an unique energy conversion property. Thermal energy can be converted into mechanical energy. Therefore, the desorption and absorption of hydrogen can be controlled by heating and cooling the metal hydride and the bellows can be moved by the hydrogen pressure. Also, this servo actuator has a pressure feedback control system using a PID controller to improve the response characteristics. The pressure feedback control system is synthesized by using the model simulation of the controlled system.
    Actually, this force output type servo actuator system was examined.
    As a result, the following facts can be specifically pointed out:
    1) The developed simulator can be useful for designing a metal hydride actuator with the higher performance.
    2) Nonlinearity of metal hydride characteristics is not a serious problem. In addition, the heater saturation can be compensated by using a PID controller with antireset windup.
    3) The impedance matching of this actuator is relatively good. The detailed analysis of this point, however, is a matter for further research in order to match a metal hydride actuator to loads over a wide range.
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  • Mignon PARK, Kiyoshi KOMORIYA, Makoto KANEKO, Takefusa OHNO, Kazuo TAN ...
    1987 Volume 5 Issue 4 Pages 283-290
    Published: August 15, 1987
    Released on J-STAGE: August 25, 2010
    JOURNAL FREE ACCESS
    One of important functions of imaging tactile sensors is object recognition in the environment where visibility is low. To achieve this function, sensor surface deformation by object contact must be detected. In this paper, a sensor system using light conductive plate is suggested for imaging tactile sensor.
    If a light is irradiated to the side of a transparent plate which is in the air, the irradiated light is reflected fully, and traveled in the plate, so far as the incident angle is less than the critical angle et the boundary area between the plate and air. When a white elastic sheet which has an uneven structure in below is put on the plate and a force is applied on the sheet, the protuberance parts of the sheet is compressed, and adhered to the plate. The fully reflected lights are scattered at the adhered Eoundary area because the full reflectance condition is broken off at that area.
    The size of adhered area is depend on applied pressure or displacement, and the intensity of the scattered lights is in proportion to the size of adhered area. Therefore, if the pattern of scattered lights is detected at the below of the plate, it is possible to evaluate the pressure distribution and deformed state which is applied at the sheet.
    According to the above principles about the sensor, we designed a new sensor system which consists of acrylic plate, elastic sheet, plastic light fibre, phototransistor matrix, light source, and microcomputer for tactile information process etc.
    Relations between sheet displacement and detected intensity of light is analized, and object pattern reconstruction is experimented with this sensor system.
    As a result, it was found that this sensor system was sufficient to get a good geometric characteristic of the pattern with information processings.
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  • Hideo YUASA, Masami ITO
    1987 Volume 5 Issue 4 Pages 291-296
    Published: August 15, 1987
    Released on J-STAGE: August 25, 2010
    JOURNAL FREE ACCESS
    When a collision-free movement of a manipulator is planned, it is necessory to detect the interference among manipulator links and obstacles. Until now, the detection has been simplified by adding various conditions mainly. But this paper proposes an interference detection method which is relatively general and is simple to calculate. Manipulator links and obstacles are approximated by convex polyhedra or these combinations. And a necessory and sufficient condition of interference between two convex polyhedra is expressed by using a relatively simple function which uses only a relation of these faces and vertices.
    And this function can be transformed easily to the one whose argument is a joint vector by using the notation of Denavit et al. Then, this method is well applied to planning collision-free movement of a manipulator because of detecting interference also in the joint space of all joint vectors.
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  • Hitoshi MAEKAWA, Tomoya KIGA, Shuji NAKATA
    1987 Volume 5 Issue 4 Pages 297-302
    Published: August 15, 1987
    Released on J-STAGE: August 25, 2010
    JOURNAL FREE ACCESS
    A weld condition library is proposed for setting of weld parameters (i. e. weld current, voltage and weld speed) in off-line programming of an arc-welding robot. The condition library consists of three parts ; experimental data base to utilize experiences of the system user, algorithm library for managing some proposed algorithms, and recommended condition data base to store some recommendations in standerds or hand-books. It is designed to be referred from a source program of the weld according to the format of the weld condition statements.
    The structure of the weld condition library and its process flow are shown by sample programs.
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  • [in Japanese]
    1987 Volume 5 Issue 4 Pages 303
    Published: August 15, 1987
    Released on J-STAGE: August 25, 2010
    JOURNAL FREE ACCESS
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  • [in Japanese]
    1987 Volume 5 Issue 4 Pages 304-305
    Published: August 15, 1987
    Released on J-STAGE: August 25, 2010
    JOURNAL FREE ACCESS
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  • Shigeki TOYAMA
    1987 Volume 5 Issue 4 Pages 306-311
    Published: August 15, 1987
    Released on J-STAGE: August 25, 2010
    JOURNAL FREE ACCESS
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  • Tsuneo YOSHIKAWA
    1987 Volume 5 Issue 4 Pages 312-316
    Published: August 15, 1987
    Released on J-STAGE: August 25, 2010
    JOURNAL FREE ACCESS
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  • Nobutoshi TORII
    1987 Volume 5 Issue 4 Pages 317-322
    Published: August 15, 1987
    Released on J-STAGE: August 25, 2010
    JOURNAL FREE ACCESS
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  • Koichi SUGIMOTO
    1987 Volume 5 Issue 4 Pages 323-327
    Published: August 15, 1987
    Released on J-STAGE: August 25, 2010
    JOURNAL FREE ACCESS
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  • [in Japanese]
    1987 Volume 5 Issue 4 Pages 328-331
    Published: August 15, 1987
    Released on J-STAGE: August 25, 2010
    JOURNAL FREE ACCESS
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  • Yukio Hasegawa
    1987 Volume 5 Issue 4 Pages 332
    Published: August 15, 1987
    Released on J-STAGE: August 25, 2010
    JOURNAL FREE ACCESS
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