1991 Fiscal Year Final Research Report Summary
Experimental Study of Dynamic Models for Robot Arms
Project/Area Number |
02452132
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Research Category |
Grant-in-Aid for General Scientific Research (B)
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Allocation Type | Single-year Grants |
Research Field |
機械力学・制御工学
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Research Institution | Osaka University |
Principal Investigator |
MAYEDA Hirokazu Osaka Univ., Dept. of Control Engineering, Associate Professor, 基礎工学部, 助教授 (30029532)
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Project Period (FY) |
1990 – 1991
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Keywords | Robot Manipulator / Dynamic Model / Identification / Model Based Control |
Research Abstract |
The purpose of this study is to experimentally establish the modeling methods for dynamic models of robot anns in the cases that 1. an ann can move freely and that 2. tip of an an-n is constrained by environment. 6 degree-of-freedom industrial robot PUMA560 and 2 degree-of-freedom SCARA type DD an-n are used in the experiments. For the case 1, (1)we experimented the step-by-step method, which this authors had proposed, to estimate the values of the base parameters, and very good estimates have been obtained. (2)The simultaneous method was also examined for the purpose, but the estimates did not converge well. (3)We tried to improve this defect of the simultaneous method by the use of the instrumental variable method and obtained as good estimates as those by the step-by-step method. (4)The affections of configurations and loads of the arms on the Coulomb's friction forces and the viscous friction coefficients of the joints were inspected, and it turned out that the tonner can be ignored
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while the latter cannot. (5)The Coulomb's friction forces and the viscous friction coefficients of the DD arm are much smaller than those of the industrial robot with reduction gears, and quite good estimates were obtained for the DD ann. As a result, it is experimentally proved that robot an-n dynamic models accurate enough for control can be obtained by the step-by-step method or the improved simultaneous method. In the case 2, we have to take into account of the stiffness or the dynamic properties of the torque transmission systems in the joints. These properties can be identified by imposing forces'bn the tip of the an-n and measuring the small position and, direction changes of the arm tip. For this purpose, (1)we had purchased 6 laser type displacement sensors and developed an apparatus which measures the 6 displacements of position and direction of the an-n tip at the same time. It turned out that the measured value by the laser type displacement sensor changes slightly depending on the direction of the object surface. We are developing a method to compensate this change and will be able to accomplish it in about one month. This caused serious delay in this research program. Thus, the identification of(2)the stiffness or(3)the dynamic properties of the torque transmission systems and(4)the analysis of the oscillations that frequently arise in the force control or the impedance control are remained to be investigated this year. Less
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Research Products
(12 results)