Periodic/Aperiodic Hybrid Position/Impedance Control Using Periodic/Aperiodic Separation Filter

Position and force controls of robots are required for tasks such as assembling and polishing. Hybrid position/force control is used to control both position and force of a multi-degree-of-freedom robot, which assigns position and force controls to different axes of the robot. Impedance control is an intermediate control of position control and force control, and hybrid impedance control is also used, which combines the hybrid position/force control and impedance control. The hybrid controls can achieve multiple control objectives with multiple-degree-of-freedom but cannot achieve multiple control objectives at a single-axis. This paper proposes periodic/aperiodic hybrid position/impedance control, where position and force are separated into periodic position, periodic force, aperiodic position, and aperiodic force with a periodic/aperiodic separation filter (PASF). The periodic/aperiodic hybrid position/impedance control assigns position and impedance controls to periodic motion and aperiodic motion at each axis of a robot. Accordingly, the proposed hybrid control achieves periodic and aperiodic control objectives at a single axis. To verify the effectiveness of the proposed hybrid control, we conducted the comparative experiments of the proposed periodic/aperiodic hybrid position/impedance control with conventional hybrid position/impedance control.