Proportional-integral-proportional control and compensation design for low-speed motions of permanent magnet synchronous motor driven servomechanism with position-dependent disturbance

Abstract

ABSTRACT Position-dependent disturbances have a significant impact on the low-speed positional motions of a permanent magnet synchronous motor (PMSM) driven servomechanism; therefore, this study has aimed to develop a control and compensation design, based on the proportional-integral-proportional (PIP) feedback control extensively used in commercialized PMSM drivers, for improving the low-speed positional motions of the PMSM-driven servomechanism without excessively increasing the computational burden on commercialized PMSM drivers and without hardware modifications to commercialized PMSM servomotor packs. The angular position and driving torque signals of the PMSM in low-speed motions were used for a spatial fast Fourier transform analysis to build the position-dependent disturbance model and determine the dominant positional frequencies. Then, a low-speed positional motion control and compensation design was developed that integrates the dynamic compensation, friction compensation, and position-dependent disturbance compensation approaches for the PMSM-driven servomechanism to improve its low-speed positional motion performance. The positional motion experiments performed on a PMSM test bench demonstrated that, in comparison with the PIP feedback control extensively used in commercialized PMSM drivers, the PIP control and compensation designed in this study improved the position and speed responses and suppressed the position and speed fluctuation phenomenon of the PMSM-driven servomechanism during low-speed motions.