Variable gain zero phase H_∞ robust tracking control for linear servo system

For permanent magnet linear synchronous motor(PMLSM) servo system,robust tracking control(strategy) based on combining variable gain zero phase error tracking(VGZPET) with H_∞ robust control is proposed.The control scheme solves the conflict between fast tracking performance and(interference) rejection of the linear serve system.The VGZPET controller is designed to ensure that the(system) has fast tracking performances and(implements) exactly tracking,at the same time,it can(overcome) the(influences) of the modelling error and parametric variation of the system.H_∞ robust controller can(overcome) the influences of external load disturbances and(uncertainties.)Therefore,the stability and robustness of the system are achieved.The simulation results show that the control scheme not only can enhance the fast tracking performance on the linear servo system,but also has a strong robustness to parametric(variations) and resistance disturbances.