Modeling and control of a high-precision tendon-based magnetic resonance imaging–compatible surgical robot

This article mainly includes the developing, dynamical modeling and control of a tendon-based robot system. First, a 5-degree-of-freedom tendon-based magnetic resonance imaging–compatible robot for prostate needle insertion surgery is introduced briefly. What follows is the dynamical modeling of the robot system, where a mechanical dynamic model is established using the Lagrange method, and a lumped parameter tendon model is used to identify the nonlinear gain of the actuator. Based on the dynamical model, a fuzzy sliding mode control algorithm is proposed for accurate position control of the robot. Through simulations using different sinusoidal input signals, we observed that the sinusoidal tracking error at 1/2π Hz is 0.2 mm and the needle tip positional precision of tracking a spatial arched curve remains less than 0.3 mm. Finally, experiments on tendon-sheath transmission and robot position tracking are conducted, which shows that the insertion precision is 0.67 mm in laboratory environment.