Design and Control of a Piezoelectric Actuated Prostate Intervention Robotic System*

Robot-assisted prostate intervention under Magnetic resonance imaging (MRI) guidance is a promising method to improve the clinical performance compared with the manual method. An MRI-guided 6-DOF prostate intervention serial robot fully actuated by ultrasonic motors is designed and the control strategy is proposed. The mechanical design of the proposed robot is presented based on the design requirements of the prostate intervention robot. The binocular vision is adopted as the in-vitro needle tip measurement method and the robotic system combined with the binocular cameras are illustrated. Then the ultrasonic motor driving controller is designed. Finally, the position accuracy evaluation of the robot is carried out and the position error is about 1.898 mm which shows a good accuracy of the robot. The position tracking characteristics of the ultrasonic motor is presented where the maximum tracking error is under 7.5° which shows the efficiency of the driving controller design. The experiments indicate that the prostate intervention robot is feasible and shows good performance in the accuracy evaluation.