Control of a permanent magnet synchronous motor using a second-order non-linear trajectory smoother

A second-order non-linear discrete trajectory smoother is coupled with conventional control law for servo-control of permanent magnet synchronous motors (PMSMs). Conventional control relies on three closed loops with linear proportional-integral-derivative (PID) controllers and gives an undesirable performance under the mismatch of system parameters and load conditions. To overcome this drawback, a discrete-time second-order nonlinear trajectory smoother is applied for the control of a PMSM. The second-order non-linear trajectory smoother is a non-linear variable structure system (VSS) catering for smooth trajectory generation for a motion control system. The trajectory smoother guarantees robustness against a change of system parameters and load conditions. Simulation and experimental studies are included to demonstrate the effectiveness of the proposed control scheme.