An optimal feedforward integral variable structure controller for the electrohydraulic position servo control systems

An optimal feedforward integral variable structure or FIVSC approach for an electrohydraulic position servo control system is presented in this paper The FIVSC algorithm combines feedforward strategy and integral in the conventional variable structure control (VSC) and calculating the control function to guarantee the existence of a sliding mode. Furthermore, the chattering in the control signal is suppressed by replacing the sign function in the control function with a smoothing function. The simulation results illustrate that the purposed approach gives a significant improvement on the tracking performances when compared with some existing control methods, like the IVSC and MIVSC strategies. Simulation results illustrate that the purposed approach can achieve a zero steady state error for ramp input and has an optimal motion with respect to a quadratic performance index. Moreover, Its can achieve accurate servo tracking in the presence of plant parameter variation and external load disturbances.