Instantaneous Voltage Regulation-based Sliding Mode Direct Torsion Torque Control for High-Backforward-Drivability Actuation

This paper proposes a high-response torque control method for a surface permanent magnet synchronous motor (SPMSM) with reduction gearing for interactive operation. In robots performing interactive tasks, backforward-drivability of the geared SPMSM is important. The backforward-drivability is defined as the ease of manipulating the load-side of the geared motor by external forces. Torsion torque control has been proposed to enhance this drivability. However, conventional torsion torque control is limited in response speed due to the high system order and reliance on a minor loop current controller. In this study, we propose a high-response sliding mode direct torsion torque control for the geared SPMSM modeled as a two-inertia resonant system. The proposed method achieves rapid response by eliminating the current controller and controlling inverter switches directly. Numerical simulations and experiments confirm that the proposed method provides high-response torsion torque control.