Heavy Object Handling System by Cooperation of a Robot and a Crane with Multiple Wires

This paper proposes a strategy for handling a heavy object by cooperation of a positioncontrolled robot and a crane with multiple wires . Installation of compliant mechanism is essential to avoid excessive inner forces caused by positioning errors of the robot and the crane. First, the necessary mechanical conditions to achieve the cooperation between position-controlled robots are reviewed . Second , compliance model of wire suspension systems are derived . After a free joint mechanism is designed assuming that the crane has three wires, a prototype of a cooperative system is developed and cooperative algorithm is proposed . The robot is position controlled as a master and the crane is velocity controlled as a slave to eliminate the displacements of free joints generated by the robot motion. The experimental results of cooperative control verified the effectiveness of the system.