Robot Workspace Optimization Based on a Novel Local and Global Performance Indices

Abstract

In this paper, a novel performance index is introduced for the kinematics optimization of serial robot manipulators. The serial robot manipulators used in order to compare optimization results were classified as in (1). The new performance index is a combination of a manipulability measure and condition number used by previous authors. To find the optimum link lengths and volumes of these robot manipulators, two design objectives are used: maximize the workspace area covered by the robot manipulator and maximize the new local index. As examples, two spherical three-link robot manipulators are examined based on above design objectives. Finally, optimization results of these robot manipulators are obtained and compared to each other. Generally speaking, a robot manipulator structure can be subdivided into a regional structure and orientation structure. The regional structure consists of the arm (first three links), which moves the end-effector to a desired position in the workspace of the robot manipulator. The orientation structure, comprised of the last three links, rotates the end- effector to the desired orientation in the workspace. In this study, the regional structure of the robot manipulators is examined rather then the orientation structure.