The Application And Research Of LMI-Based H-Infinity Control In Electric Hydra Ulic Force Control System

Generally, there are many parameter variations and load disturbances in modern hydraulic servo control system. The second order link in the Transfer function of electro-hydraulic control system make the system oscillation or even instability.There is an urgent need to design control system with high degree of accuracy and high adaptability.This article is based on the electro-hydraulic drive control system. Apply H_∞control theory to the hydraulic systems. First, establish the transfer function of electro-hydraulic drive control system by the traditional linear method, and then establish the nonlinear model of systems to make it more close to the actual system. Analyze the parameters on the system performance,and design the H_∞controller by the LMI to reduce the impact of parameters on the system and improve system performance.The control problem of the electro-hydraulic drive control system is easy to appear singular phenomenon, and the traditional H_∞control theory can't solve this problem,so this article use the LMI-based H_∞control to solve it. This article give the detailed derivation and design method of LMI-based H_∞control, and also give the principle of select weight function. Then reduce the order of the controller to make it easy to realize.Classical control theory is used to design the PID controller, and compare the bandwidth,the anti-jamming capability and the robustness between the PID controller and the H_∞controller by the simulation and experimental. The results show that H_∞controller can make system have higher bandwidth and the more power robustness. At the last, analyze the feature of these controllers in frequency domain, and explan the reason why PID controller and H_∞controller has different feature.