A method for estimation of operational torque with utilizing a hysteresis model

Along with the population aging, human interactive robots are expected to be introduced in our daily lives especially in developed countries. For such robots, bilateral control is widely researched as a technique for transmission of both position and force information. Reaction force/torque observer (RFOB/RTOB) is often utilized in bilateral control system to estimate reaction force/torque from objects. It achieves a sensorless control system. However, it requires accurate estimation of operational force/torque for precise approximation of reaction force/torque. This paper proposes a method for estimation of operational torque. In this method, a hysteresis model is utilized to reduce vibration which occurs when the velocity shakes at low velocity. The validity of the proposed method is confirmed by experimental results.