The Application And Research Of Lmi-Baeed Robust Control In Electric Hydraulic Force Control System

The hydraulic control system has been widely adopted in all industries in the modern production. But as its working environment and load conditions changing, and some sudden factors, the hydraulic control system will have a large degree of interference. Especially for the electro-hydraulic drive control system, when a certain or some parameters in the system have a change in larger scope, the stability of the system will have great influence, even it's not very stable. Therefore, it's necessary to make the hydraulic control system upgrade and improvement, to improve its accuracy and stability.This article researches the application of robust control theory in the hydraulic control system , based on the foreign research results in the related fields and the electro-hydraulic drive control system for the research background through researching and analyzing the electro-hydraulic servo control system and robust control theory, and other aspects in the domestic and foreign.Firstly a simple and understandable linearization method is adopted to build the corresponding modeling for the electric hydraulic control system, and the transfer function is deduced. Secondly, to make the system be more practical, its nonlinear model is built, and the effect is analyzed about each parameter on the system performance. Once again the paper derives the robust controller based on linear matrix inequality (LMI) method and the selection principle about the general situation of the weight function on the basis of the nonlinear model, in order to achieve the purpose of improving the system overall performance.This paper also selects many different weight functions according to the general selection principle of the weight function, and verifies them to test its rationality. At the same time the designed robust controller is reduced its order processing, facilitating its implementation in practical application.For inspecting the advantages and disadvantages of robust controller, this paper also designs the double inertial controller, and makes some analysis and comparisons in the simulation and experiment separately for both above. The consequence shows that in the case of the parameters no change or small changes, the double inertial control effect is superior to the robust controller; For the system whose parameters have a great scope change, the robust controller has better control effect, and shows a strong adaptability when the parameters have a large scope change.Finally, for different characteristics on the both of robust controller and double inertial controller ,this paper does some analysis in the frequency domain, and obtains the reasons why the two control methods have different performance in different situations.