Inverse Jacobian based hybrid impedance control of redundant manipulators

This paper presents an efficient control scheme for compliant motion control of kinematically redundant manipulators and its evaluation using an experimental 7 degrees-of-freedom manipulator, REDIESTRO (a redundant dexterous isotropically enhanced, seven turning-pair robot). An inverse Jacobian based hybrid impedance control (IJ-HIC) scheme is proposed that provides a unified approach for combining compliant motion control, redundancy resolution, and user defined secondary tasks in a single methodology. The IJ-HIC uses the inverse of the manipulator Jacobian together with PD control and feed-forward computed torque to track desired force and position trajectories. The scheme is capable of controlling force and position of redundant manipulators and utilizes the manipulator redundancy by achieving user-defined additional tasks. The IJ-HIC is implemented for real-time control of REDIESTRO. Simulation and experimental results validate the IJ-HIC scheme, and demonstrate its capabilities for performing various tasks.