The Collision-Free Workspace of the Tripteron Parallel Robot Based on a Geometrical Approach

Abstract

Parallel robots, despite many kinematic features, generally have limited workspace. Therefore, it is paramount importance to obtain the workspace by considering the mechanical interference. In this paper, the mechanical interference, including collision of links, collision of links with obstacles, collision of the end-effector with obstacles, are investigated by using a new geometrical reasoning. For this purpose, a new geometric method is proposed which is based on the segment to segment intersection test. This method can be well extended to a wide range of robotic mechanical systems, including, among others, parallel robots. Moreover, in this paper, an index is introduced which can be used to examine the workspace with respect to mechanical interference. Furthermore, the aforementioned index provides some insight into obtaining a well-conditioned workspace. For the sake of validation, as case study, the proposed method is implemented to a spatial 3-DOF parallel robot, known as the Tripteron.