Transparent Bilateral Control with On-line Identification of Tissue Parameters for Telesurgery Robotic Systems

In this paper, a transparent bilateral controller is developed for the control of telesurgery systems that have physical interactions with soft tissue. In this control method, the parameters of a viscoelastic model of the soft tissue are estimated during its interaction with the slave robot using an on-line identification method. These estimated parameters are used in an impedance control of the master robot which is in contact with the surgeon. Also, the slave robot tracks the master robot position using a tracking controller. Accordingly, it is shown that the transparency of the teleoperation system is obtained by estimating and realizing the dynamic parameters of the tissue for the master robot and providing the position tracking performance for the slave robot. The stability, and the position and force tracking performances are proved using the Lyapunov theorem. Moreover, the effectiveness of the proposed transparent bilateral controller is investigated by simulations performed on a piece of beef (as the soft tissue) using a two DOF robot with nonlinear dynamics. The proposed control strategy can be used in telesurgery, telesonography and telerehabilitation systems in which the robot interacts with soft tissues.