A Consideration for Controlling All State Variables of Torque-unit Manipulator(TUM)

Abstract

The Torque-unit Manipulator (TUM) is proposed as a novel type of manipulator for space applications, featuring joints without internal motors. Instead, it utilizes torque-units, consisting of a disc and a motor, attached at any position on each link. The operational principle involves the motor rotating the disc, with the reaction torque driving the link. Advantages of TUM include ease of maintenance and the potential for redundant actuator systems. However, controlling TUM presents a challenge: after the links reach their target positions, residual angular velocities remain in the discs. Previous research suggests this can be mitigated by moving the links beyond their targets and then back to the target positions, but finding the precise angle remains largely heuristic. This study investigates the necessary angle set to achieve zero residual angular velocity in the discs, aiming to refine control strategies for TUM.