EXTREME REACHES AND REACHABLE WORKSPACE ANALYSIS OF GENERAL PARALLEL ROBOTIC MANIPULATORS

This article presents a systematic numerical method for analyzing the extreme reaches and the reachable workspace of general parallel roboti c manipulators. In this method, finding the extreme reach is formulate d as an optimization problem. The closed loops of the robot are virtua lly disconnected into open kinematic chains. Violations of the loop cl osure constraints and the position error of the end-effector are inclu ded in the objective function as penalty terms. This formulation not o nly is conceptually straightforward, but also can effectively reduce t he problem size. The problem is solved by using a two-stage sequential unconstrained minimization algorithm. A procedure for determining the boundary surfaces of the reachable workspace is also presented. (C) 1 998 John Wiley & Sons, Inc.