A PARALLEL APPROACH OF THE INVERSE KINEMATICS SOLUTIONS FOR ROBOTS USING A TRANSPUTER NETWORK

This article presents a parallel method fur computing inverse kinemati cs solutions for robots with closed-form solutions moving along a stra ight line trajectory specified in Cartesian space. Zhang and Paul's ap proach(1) is improved for accuracy and speed. Instead of using previou s joint positions as proposed by Zhang and Paul, a first order predict ion strategy is used to decouple the dependency between joint position s, and a zero order approximation solution is computed. A compensation scheme using Taylor series expansion is applied to obtain the traject ory gradient in joint space to replace the correction scheme proposed by Zhang and Paul. The configuration of a Mitsubishi RV-MI robot is us ed for the simulation of a closed-form inverse kinematics solutions. A n Alta SuperLink/XL with four transputer nodes is used for parallel im plementation. The simulation results show a significant improvement in displacement tracking errors and joint configuration errors along the straight line trajectory. The computational latency is reduced as wel l. The modified approach proposed in this work is more accurate and fa ster than Zhang and Paul's approach for robots with closed-form invers e kinematics solutions. (C) 1996 John Wiley & Sons, Inc.