Variable impedance bilateral control for object discrimination in microsurgery

Recently, laparoscopic microsurgery using master slave system has been gotten a lot of attention. However, as the current system implemented is not capable of presenting haptic sense to operators, it places a large burden on operators. In addition, it is also necessary to enlarge the kinesthetic sense so that the operators can perceive small reactive force against a patient's body. The reactive force on the slave is minute in microsurgery. Therefore, it is necessary to expand the reactive force recognize the object. However, when the reactive force is expanded by a constant ratio, the distinction of the object becomes difficult. In this paper, in order to solve this problem, we propose variable impedance control. The bilateral control consists of contact mode and free motion mode. In the free motion mode, a constant impedance model is used. In the contact mode, estimate the impedance of the object and vary the control model. As a result, the characteristic of the object is clearly reproduced on the master, and the distinction of the object can be facilitated.