Evaluations on contribution of backdrivability and force measurement performance on force sensitivity of actuators

The importance of force measurement and back-drivability in realizing force sensitive actuator is widely acknowledged. There are studies on fidelity of torque sensors and backdrivability individually, but limited study are made on investigating effect of torque fidelity and backdrivability on force sensitivity of the actuation system. In this paper, we developed backdrivable electro-hydrostatic actuator equipped with torque sensor to analyze the effect of torque fidelity and backdrivability on force sensitive control system. We implemented friction compensation controller and evaluated force sensitivity of the actuator by residual friction torque after the friction compensation. Method using pressure sensor and torque sensor were compared. Effect of backdrivability was performed by comparing friction torque of Harmonic Drive joint and joint with developed actuator.