Methods for reduction of operational force in force sensor-less bilateral control with thrust wire

Force sensor-less bilateral control with thrust wire can realize low-cost bilateral applications and is very useful. However, there is a problem. Since modeling of the thrust wire is very difficult, there is disturbance from modeling error of the thrust wire. Thus, an operator feels heavy operational force caused by friction of the thrust wire. This is not suitable for bilateral control. Purpose of this research is to reduce of the operational force in force sensor-less bilateral control with the thrust wire without precise modeling, extra sensors, or extra actuators. A force transform that is a transform of estimated reaction force is presented for the thrust wire. Additionally, bilateral control methods with the force transform are proposed. Using the proposed methods, reduction of the operational force is realized. The validity was confirmed by some experiments.