To control the position and movement of an end-effector on the tip of a multi-joint robot arm is known to include a kind of redundant problem. Although the end-effector is set its position by each angle of the joints, the angle of each joint cannot be uniquely determined by the position of the end-effector. Each of infinite number of different sets of joint angles usually represent the same position of the end- effector. This paper describes how to control the angle of each joint to move its end-effector from a starting point to an ending point on an X-Y plane preferably. We first separate standpoints into two to define the preferable movement; 1) the standpoint of the end-effector, and 2) the standpoint of the joints. Then, we define multiple objective functions from each standpoint. Finally, we formulate the problem into a multi-purpose programming problem. We apply a genetic algorithm to solve this problem and obtain satisfied solutions, which have a smooth movement of the end-effector and less rotation of the joints. This paper is suggestive that the approach described here can easily be extended to a problem with a multi-joint robot arm in a 3D space, and also to a problem with obstacles between starting and ending points.

Date Published: 26 August 1999
PDF: 9 pages
Proc. SPIE 3837, Intelligent Robots and Computer Vision XVIII: Algorithms, Techniques, and Active Vision, (26 August 1999); doi: 10.1117/12.360286

Published in SPIE Proceedings Vol. 3837:
Intelligent Robots and Computer Vision XVIII: Algorithms, Techniques, and Active Vision
David P. Casasent, Editor(s)