Bilateral control for remote controlled robotic forceps system with time varying delay

Recently, development of the surgical support devices with the application of robot technology is in demand. We have developed a multi-DOF robotic forceps manipulator using a novel omnidirectional bending mechanism, and for the developed robotic forceps manipulator, we proposed a passivity based bilateral control that enables motion scaling in both position tracking and force tracking, and guarantees the stability of the teleoperation system in the presence of constant time delay, so far. In this paper, the passivity based bilateral control is extended so as to guarantee the stability of the teleoperation system not only in the presence of the constant time delay but also in the presence of the time varying delay. In order to verify the effectiveness of the proposed control law, experimental works were carried out for the developed robotic forceps teleoperation system.