Bilateral control of a half-circle-shaped tubular linear motor with disturbance model based on trigonometric function of two variables

In robotic surgery without contact force transmission characteristic between master and slave system, the risk of a medical mistake becomes high. Then, a novel surgical assistance robot with force transmission is expected to be developed. This paper firstly introduces a two-degree-of-freedom (2-DOF) haptic system which can realize pitching motion and yawing motion. The system is composed of four half-circle-shaped tubular linear motors. Then, this paper focuses on the pitching motion system of the 2-DOF system. In this system, the effect of gravity and friction force is changed by the position and the velocity of motor. This paper proposes a disturbance model based on a trigonometric function of position and velocity for this system. It realizes vivid force transmission between master and slave motor in bilateral control. Bilateral control test of this system with disturbance model is performed. Experimental results are presented to validate the proposed model.