Preview and Postview Control System for Trajectory Tracking and Obstacle Avoidance to Unknown Ojbects for Redundant Manipulators.

Abstract

This research is concerned with a control method for trajectory tracking and obstacle avoidance by redundant manipulators. When an operation system dose not require preparations about positioning and definition of a contour of a working object, the working efficiency will be improved. Working to unknown objects is desired to be executed automatically. When a trajectory of manipulator's hand is on the surface of the object, the object could be an obstacle, and both the trajectory tracking and obstacle avoidance must be controlled parallel in the same time. We have formerly presented a redundancy control system using a preview control to achieve simultaneously these two tasks. The preview control system is a method to change the current arm form by referring to the form in the future. However, the manipulator sometimes happens to collide against the passed obstacle. This paper proposes a new redundancy control method to solve this problem. This system consists of both the preview and postview controls, considering into the past arm form by using its redundancy. This system is applied to objects which contour is concave and the effectiveness is verified through simulation experiments.