Based On Robust Control Of Hydraulic Servo System Semi-physical Simulation

Electro-hydraulic position servo control system is the important part of the control fields nowadays. Thickness system of hydraulic mill stand roll-gap is the test device, which is used in the study, and the system is a typical electro-hydraulic position servo control system. For the feature of the parameter uncertainty in the electro-hydraulic position servo system, in the paper, two robust controllers are designed, and which are achieved by the DSP controller.Firstly, the paper establishes mathematical model of the electro-hydraulic position servo control system, and designs a robust PID controller of the system, based on the distance between the points of the Nyquist curve of the sensitivity function of the open loop transfer function of the system mathematical model and the critical stable point (-1,j0).In the case of increasing and decreasing the parameters of the mathematical model of the system, the paper analysis the differences between the unit step response curve of the control system and the unit step response curve of the PID controller based on the amplitude and phase margin, demonstrates robust performance of the robust PID controller.Secondly, the paper describes the uncertainty factors which the system exists and the impact of the system. And thus, the paper describes the origin of the design of robust controller, and the theory basis of designing H_∞controller and the selection principle of the weighting function when someone design the mixed sensitivity H_∞controller. Based on the method of designing the mixed sensitivity H_∞controller, the paper designs the mixed sensitivity H_∞controller of thickness system of hydraulic mill stand roll-gap.Finally, according to the robust PID controller and the mixed sensitivity H∞controller which the article designs , the paper achieves the function of two robust controller used the digital signal processor of TMS320F2812. To verify the controlled performance of the DSP robust controller, the paper designs the electrical simulator of mathematical model of the electro-hydraulic position servo control system. Through the test of the DSP robust controller and the electrical simulator, and the comparison of the unit step response curve of the system with the simulation curve , the paper proves that the DSP robust controller which is designed is consistent with the desired control.