H[infinity] Robust Tracking Control for Periodic Disturbance Signal in Piston Machining Based on the Learning Feedforward Compensation

A robustness tracking control scheme based on combining learning feed forward control (LFFC) with H_∞ robust control is proposed for convexity variable ellipse piston linear servo system. On the basis of analyzing the disturbance signal of the system, LFFC based on B-spline network is designed to ensure that the system has fast tracking performance and implements exactly tracking. H_∞ robust control as feedback controller can overcome influences of the uncertainties of the parameters perturbation, the load disturbances and so on to achieve the stability and robustness of the system. The simulation results show that the scheme not only can enhanced the fast tracking capability of the system, but also reduce the influence of the uncertainty disturbances.