A Backdrivable Kinematically Redundant (6+3)-Degree-of-Freedom Hybrid Parallel Robot for Intuitive Sensorless Physical Human–Robot Interaction

A novel backdrivable 3-[ R ( R- RR)SR] kinematically redundant (6+3)-degree-of-freedom (DOF) spatial hybrid parallel robot with revolute actuators is proposed for low-impedance physical human–robot interaction. The kinematic model developed based on the constraint conditions of robot. It shown that type II (parallel) singularities can be completely avoided, thereby yielding a very large translational and orientational workspace. workspace analysis presented in order to demonstrate capabilities Mechanisms are then introduced use DOF operate gripper actuators, which mounted or close base, thus reducing inertia moving parts. architecture makes it possible direct drive motors, making easily allowing simple effective controller. prototype designed built as well effortless interaction demonstrated. controller described, including position control mode interaction, does not require force/torque sensor joint torque sensors. Because its backdrivability low inertia, particularly well-suited demonstrated accompanying videos.