| The electro-hydraulic servo system has been widely used in military, civil and other fields with its advantages such as high control accuracy, quick response, big perform stiffness. However, the electro-hydraulic servo system also has disadvantages like model uncertainty, load time-varying, system nonlinearity, so the conventional PID control method can hardly get satisfactory control quality. Research on new type intelligent control algorithm for electro-hydraulic servo system is of great value in theoretical research and engineering application.In order to improve the dynamic and static performance of electro-hydraulic servo system, the fuzzy-PID control algorithm is improved to practical engineering in this paper. Firstly, the theory of PID and fuzzy control algorithm is studied, and the shortcomings existing in traditional fuzzy-PID control algorithm are analyzed. According to the characteristics of the electro-hydraulic servo system, an improved variable universe fuzzy-PID (VFPID) control algorithm is proposed on the basis of normal variable universe fuzzy controller by adding a fuzzy intelligent integral controller. The VFPID algorithm is designed detailly, and the simulation experiments of three typical system models are conducted to verify the feasibility of the algorithm. Finally, the VFPID algorithm is applied to the electro-hydraulic servo system of the chain tension tester, and then the simulation experiment and the real-time control experiment are conducted according to the time-varying property of the system parameters under different working conditions.The experiments show that the VFPID algorithm can achieve favorable control precision and robust performance without mathematical model of the process. Compared to the normal PID method, the VFPID algorithm get the better control quality for nonlinear time-varying servo system with high value of engineering application. |
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