Study On The Electro-Hydraulic Proportional Position System H_∞ Mixed Sensitivity Control Technology Applications

Based on the hydraulic damper test bench in the laboratory, the theory of H-mixed sensitivity control which is based on the genetic algorithms is applied to the electro-hydraulic proportional position system.In this article, a mathematical dynamical model of the electro-hydraulic proportional position system is built. Based on the simulation results, we can found that large range of model parameter variations and the exterior disturbance can make great influence on the system . It is very difficult for an electro-hydraulic proportional position system with traditional method to solve the problems of the uncertainties caused by them. Robust control theory can design a controller whose structure and parameters are unchanged and can make the closed loop system maintain the performance with uncertainties. H_∞mixed sensitivity control theory is one of the typical robust theory, it can solve the tracking problem, anti-disturbance problem and robust stabilization problem at the same time. Therefore, this paper puts stress on the application of H_∞mixed sensitivity control theory which is based on genetic algorithms to the electro-hydraulic proportional position system.The selection of weighting function is very important in H_∞mixed sensitivity controller's design for systems. Aiming at the delay and no specific selection of weighting functions, a new algorithm is brought forward. In this article, the genetic algorithms is used to select the weighting functions, a fitness function which contains the system's robustness and closed-loop dynamic performance is given and the best H_∞controller for the electro-hydraulic proportional position system is found by the program automatically.The simulation and experiment results show the H_∞mixed sensitivity controller which is based on genetic algorithms has better control abilities than the H_∞mixed sensitivity controller and PID controller. The electro-hydraulic proportional position system based on it has good robustness and closed-loop dynamic performance. The test bench which is under the controller designed though the method given by this article can simulate the 10Hz sine wave, reflects the relationships of the hydraulic damper's force, position and speed.