2005 Fiscal Year Final Research Report Summary
Analysis and Control of High Compliance Systems with Coulomb Friction
| Project/Area Number |
15360222
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Control engineering
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| Research Institution | University of Tsukuba |
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Principal Investigator |
AOSHIMA Nobuharu University of Tsukuba, Gradute School of Systems and Information Engineering, Professor, 大学院・システム情報工学研究科, 教授 (60013710)
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| Co-Investigator(Kenkyū-buntansha) |
YABUNO Hiroshi Univ.of Tsukuba, Graduate School of Systems and Information Engineering, Professor, 大学院・システム情報工学研究科, 教授 (60241791)
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| Project Period (FY) |
2003 – 2005
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| Keywords | Underactuation / Compliance / Nonlinear / Parametric resonance / Robot / Manipulator / Flexible arm |
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| Research Abstract |
First, we show the effects of slight Coulomb friction on a simply supported beam under compressive force, which is a high compliance system. The governing equation, which is a nonlinear partial differential equation, is deduced. By the method of multiple scales, the system is analyzed. As a result it is clarified that very low stiffness and Coulomb friction produces infinite number of stable equilibrium states. The phenomena are identified by bifurcation theory. And the validity of the theoretical result is experimentally confirmed. The high- frequency excitation destabilizes these stable equilibrium points and stabilizes the buckled beam to the straight position. Also, experimental identification method for Coulomb friction is proposed. Furthermore, we propose a motion control of an underactuated manipulator, which is high compliance system. The high frequency excitation produces variety of stable equilibrium states. The change of the excitation direction perturbs the bifurcation phenomena and carries out the position control of the under actuated link without state feedback control. Experimental apparatus of the underactuated manipulator is constructed. The validity of the proposed control method is experimentally confirmed. Furthermore, we consider the case when the underactuated link is flexible. The equation of motion is partial differential equation. Under high-frequency excitation of the active link, the dynamics of the underactuated link is analyzed by introducing multiple time scales. Also, in this case, experiments are conducted and the motion control of flexible underactuated manipulator is experimentally confirmed. Finally, we consider the application of the high compliance system for grip. The grip does not give impact objects because the joint of the grip is freely rotated. This system uses high frequency excitation and carries out motion control.
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