Control of an actively constrained robotic joint for passive deployment applications

The design and control of an actively constrained revolute joint with backlash cancellation for passively deployed devices is presented in this paper. The drive mechanism consists of two motor-driven worms coupled to a single worm wheel. A mathematical model of the system is used in order to develop a backlash cancellation strategy and computed-torque motion control algorithm. Experimental results show that the position of the joint can be successfully controlled to track a trajectory generated from a user-input force command signal while cancelling backlash at the gear interface.