High back-drivable pseudo I-PD torque control using load-side torque observer with torsion torque sensor

This paper proposes high back-drivable pseudo I-PD torque control using load-side torque observer with torsion torque sensor. According to previous research, the back-drivability of torsion torque control using torsion torque sensor depends on load-side friction. Therefore, the authors focus on load-side torque control. Load-side torque is estimated using load-side torque observer because load-side torque cannot be detected in this system. Using estimated load-side torque feedback, the back-drivability of the proposed method becomes infinite. The back-drivability of the three methods (i.e., P-D, I-PD, and pseudo I-PD) are compared using the simulation and experimental results. Finally, the simulation and experimental results verify the effectiveness of the proposed method.