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Volume 21 Issue 05/06 - Publication Date: 1 May 2002
 
Nonholonomy on Purpose
 
Controllability of Under-Actuated Planar Manipulators with One Unactuated Joint
 
Keigo Kobayashi Department of Systems and Human Science Osaka University Toyonaka, Osaka 560-8531, Japan kobayasi@sys.es.osaka-u.ac.jp and Tsuneo Yoshikawa Department of Mechanical Engineering Kyoto University Sakyou-ku, Kyoto 606-8501, Japan yoshi@mech.kyoto-u.ac.jp
 
This paper is concerned with analysis on controllability for a class of nonholonomic systems. We discuss controllability of underactuated planar manipulators with one unactuated joint. We show that if the first joint (in the base side) is actuated, these systems are completely controllable, namely, there exists an admissible trajectory from any given initial point to any given final point. In order to prove this, we use global stabilizing feedback control law to converge the state to a manifold, where the system is locally controllable. By this controller, we have two trajectories, one starting at the given initial position and the other starting at the given final position. Then we connect them using a kind of bi-directional approach to show the existence of the whole admissible trajectory. Finally, we give some simulation results to discuss controllability of more general cases, the first joint being actuated and all other joints being unactuated.
 
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