Z. Wu’s scientific contributions

For the direct drive permanent magnet linear synchronous motor (PMLSM) servo system, the load disturbance and the parameters changes will influence the performance of the servo system seriously. A disturbance compensation method of position controller combined with optimal parameter disturbance compensating controller was proposed. It ensured that the system had fast transient response and good load disturbance rejection capability. The position controller determined the transient response performance and the load compensator improved the ability of disturbance suppression. And by using the Parseval theorem, its parameters were obtained from an optimization technique that transformed the position deviation of the performance index from time domain into the frequency domain, and then the Routh-Hurwitz two-dimensional array was calculated to obtain the optimal proportional-integral parameters. The simulation and experimental results show that the proposed compensation method enhances control precision and robustness of the system.