Development of a Cooperative System Comprised of a Robot and a 7 D.O.F. Crane with Three Wires.

Abstract

We propose a strategy for cooperation between a position controlled manipulator and a crane with three wires. A compliant mechanism consisting of three free joints is designed and installed at the tip of the manipulator to avoid excessive inner forces due to mutual positioning errors of the manipulator and the crane. Since the cooperative system with the compliant mechanism becomes kinematically redundant, the characteristics of the redundancy are analyzed and a way to exploit the redundancy is discussed. The robot is position-controlled as a master and the crane is velocity-controlled as a follower by the feedback signals from the sensor systems of the crane and the free joint mechanism. The experimental results obtained using a prototype cooperation system verify the effectiveness of the cooperative strategy and the system architecture.