Robot motion control using mechanical load adjuster with motion measurement interface for human-robot cooperation

The development of a robot motion control scheme and a mechanical load adjuster with a motion measurement interface is addressed in this paper. To improve the efficiency of a task involving human-robot cooperation, we designed a novel robot control system, in which a multiple-load state can be provided for a human operator. This system also can provide a multiple-dynamics state during a task involving human-robot dynamical cooperation. The multiple-load state including its transition is effective and efficient in such a task. A single load state can be easily provided by the impedance control of the robot motion thus far; however, the multiple-load state and its transition are difficult to realize using a conventional control scheme. The proposed control scheme differs widely from a conventional impedance control scheme in that the multiple- load state as well as both active and passive states cannot be induced in the single robotic system. Under the proposed control scheme, the load state can be adjusted with the various dynamics in the active or passive state. To confirm the effectiveness of the proposed control system, human-robot cooperative experiments were carried out. Results showed that the proposed control scheme can provide the multiple-load state for use in a human-robot cooperative task system.