Abstract: The electro-hydraulic servo loading system often exist the problems of large-scale load disturbance and nonlinear disturbance, traditional PID control strategy is generally difficult to solve. Aiming at this problem, in order to effectively improve the dynamic quality and steady-state accuracy of position servo, an electro-hydraulic position servo loading system based on open loop compensation and robust control was proposed. Firstly, the composition structure and mathematical model of an electro-hydraulic servo loading test-bed system were introduced. Then the nonlinear open-loop compensation method for restraining disturbance was discussed, the position open-loop compensation control strategy based on expected trajectory planning was analyzed, the characteristics of on-line prediction of nonlinear parameters of the system were described, and the theoretical model of position servo controller was established. The principle and method of adaptive robust control strategy for position servo system were expounded. Finally, the electro-hydraulic servo loading system experiment was carried out to verify the superiority of the electro-hydraulic position servo loading system based on open loop compensation and robust control. The research results indicate that 
comparing with the electro-hydraulic servo system adopting PID closed-loop mode, the electro-hydraulic position servo loading system based on open-loop compensation and robust control has stronger adaptability, higher position tracking curve control accuracy, when the position tracking frequency is 20Hz, the tracking error is only about 15% of the position command amplitude, the “double ten” bandwidth of the system can be extended to 22Hz,and the overall anti disturbance performance is obviously better than the electro-hydraulic servo system with PID closed-loop mode.

Key words:  electro-hydraulic servo loading system; position servo; open loop compensation; robust control; restraining disturbance

MEI Lu-hai, LIU Zhe-wei. Electro-hydraulic position servo loading system based on open loop compensation and robust control［J］.Journal of Mechanical & Electrical Engineering, 2022,39(1):59-64,86.