Development of a parallel wire mechanism for measuring position and orientation of a robot end-effector

Abstract

This paper presents a parallel wire mechanism developed for measuring six degrees of freedom of a robot end-effector: The mechanism consists of six parallel wire links. The position and orientation of a robot are obtained from the wire lengths measured in the parallel wire mechanism. The complex nonlinear equations of th forward kinematics are solved by using a Newton-Raphson method, and a unique solution is determined from the geometric configuration of the developed mechanism. The wire length error caused by longitudinal deformation of the wires is compensated by a wire compensation factor. Through the experiment, it is verified that the developed mechanism has an accuracy of +/-0.05 mm, +/-0.1 degrees in the position and the orientation, respectively. The developed parallel wire mechanism can be used effectively for measuring the position and orientation of a six degree of freedom (DOF) of robot end-effector with low cost and effort. (C) 1998 Elsevier Science Ltd. All rights reserved.