Cooperative system for multiple position-controlled robots with free joint mechanisms

This paper proposes a simple method for handling objects by cooperation of multiple position-controlled robots. In order to use position controllers for cooperation of multiple robots, it is necessary to install mechanical compliance in each robot to avoid excessive inner forces due to the mutual positioning errors. First, the compliance needed for the cooperation of position-controlled robots is reviewed. Using compliant mechanisms with free joints, cooperative control system between two industrial robots are developed. As the cooperative system with mechanical compliance has kinematic redundancy, a way to use the redundancy is proposed. Some fundamental experiments verify the effectiveness of the proposed strategy