Fine Force Sensorless Force Control Based on Friction-Free Disturbance Observer

摘要

This paper proposes force sensorless force control by using a notch-type friction free disturbance observer. The force control is structured by using acceleration and speed controllers. The reaction force estimation system reduces the effect of the static friction using a dither signal. A conventional friction free disturbance observer becomes unstable when a low-frequency dither signal is applied. In order to solve this problem, a notch-type friction free disturbance observer is employed, which allows the use of low-frequency dither signals. This paper explains the difference between the conventional design method and the proposed design method. The validity of the proposed notch-type friction free disturbance observer is verified through the experimental results by using an actual industrial robot.