Development of an extended proportional–integral–proportional control for improving positional motion performance of permanent magnet synchronous motor‐driven servomechanism

Abstract

To achieve high‐speed and high‐accuracy positional motions in a permanent magnet synchronous motor (PMSM)‐driven servomechanism, this study developed an extended proportional–integral–proportional (PIP) control, particularly by considering the limitations of the hardware structure of commercialized PMSM drivers. PIP feedback and feedforward controls were developed, such that the existing PIP feedback control, which is extensively used in commercialized PMSM drivers, can perform dynamic and friction torque compensations in PMSMs. Thereafter, an extended PIP control with the newly added design degrees of freedom was developed based on the PIP feedback and feedforward control structures, thereby further improving the position response of the PMSM‐driven servomechanism and positional motion performance of advanced motion control systems. Position control experiments were performed on a commercialized PMSM pack installed on the rotary table of a five‐axis computer numerical control (CNC) machining center. Results indicate that the extended PIP control can significantly reduce position errors, which can be minimally influenced by the change in frequency of the position command. Furthermore, circular motion experiments were performed along the motion axes of the five‐axis CNC machining center. Results indicate that the extended PIP control with dynamic matching design can significantly reduce the root‐mean‐square value of contouring errors and roundness error value. Experimental results validate the feasibility of the extended PIP control for improving the positional motion performance of the PMSM‐driven servomechanism.