Speed control of non-collocated stator-rotor synchronous motor with application in robotic surgery

This paper introduces Non-collocated Stator-Rotor Synchronous Motor (NSRSM) as a novel actuation system for cases where the stator and rotor are required to interact across a physical barrier. The main motivation for NSRSM is in the area of laparoscopic robotic surgery whereby it is desired to actuate the manipulators across the abdominal wall, but it also has potential application in other robotic surgery procedures. The configuration of NSRSM is similar to that of permanent magnet synchronous motor (PMSM) although due to asymmetric structure of the windings around the rotor, the electromechanical model of PMSMs was developed to obtain the dynamic model of NSRSM. The field oriented control method is used to develop an appropriate model for control purposes. Then two widely used control algorithms (PI controller and linear quadratic regulator (LQR)) are used to control the rotor speed in the presence of the modelling uncertainties and load disturbances. Simulation results show that these two methods are robust.