Decentralized control of multiple manipulators handling an object in coordination based on impedance control of each arm

We propose a decentralized control algorithm of multiple manipulators handling a single object in coordination. The proposed algorithm is a leader-follower type; the motion command of the object is given to one of the manipulators, referred to as a leader and the other manipulators, referred to as followers, estimate the motion of the leader by themselves through the motion of the object and handle the object based on the estimated motion. Different from the conventional leader-follower type of control algorithms, each manipulator is impedance-controlled and has equal dynamic characteristics. The stability of the resultant system with the decentralized control algorithm is also guaranteed. The proposed control algorithm is experimentally implemented in two industrial manipulators and the experimental results illustrate the validity of the system.