A time-varying coefficient-based manipulability-maximizing scheme for motion control of redundant robots subject to varying joint-velocity limits


Correspondence to: Yunong Zhang, School of Information Science and Technology, Sun Yat-sen University, Guangzhou 510006, China.

E-mail: zhynong@mail.sysu.edu.cn; jallonzyn@sina.com


A time-varying coefficient-based manipulability-maximizing (TVCMM) scheme subject to varying joint-velocity limits (VJVL) is proposed and investigated in this paper for the optimal motion control of redundant robot manipulators (where a planar robot manipulator is specifically considered). In order to improve the manipulability during the end-effector task execution, a manipulability-maximizing index is considered into the scheme formulation. Besides, for the remedy of the nonzero initial/final joint-velocity problem, a time-varying coefficient is introduced and incorporated in the scheme, which is further reformulated as a quadratic program (QP) subject to equality and bound constraints. For guaranteeing the physical realizability of such a scheme, an efficient linear variational inequality-based (LVI-based) numerical algorithm is employed to solve such a QP, and an experiment based on a 6-DOF manipulator is presented, of which the redundancy is on the horizontal plane. Simulative and experimental results validate the physical realization, effectiveness, and accuracy of the proposed QP-based manipulability-maximizing scheme. Copyright © 2012 John Wiley & Sons, Ltd.