Torque Sensorless Control in Multidegree-of-Freedom Manipulator

The paper describes a torque sensorless control in a multidegree-of-freedom manipulator. In the proposed method, two disturbance observers are applied to each joint. One is used to realize the robust motion controller. The other is used to obtain a sensorless torque controller. First, a robust acceleration controller based on the disturbance observer is shown. To obtain the sensorless torque control, it is necessary to calculate reaction torque when the mechanical system performs a force task. Second, we explain the calculation method of the reaction torque. Then the proposed method is expanded to workspace force control in the multidegree-of-freedom manipulator. Finally, several experimental results are shown to confirm the validity of the proposed sensorless force controller.