Study On The Hydraulic Nonlinear Control System Of The Rolling Machine

The rolling machine hydraulic system is divided into two parts in thisarticle. One is the hydraulic control part, the other is the hydraulic transmission part.Due to the inherent characteristics of the hydraulic system, such as larger degreetime-varying of parameters, valve flow characteristics, the load disturbance, obtaininga precise mathematical model of nonlinear problem, and so on, it causes that the linearmodel of rolling machine hydraulic system can not satisfy the rolling requirement ofrolling machine. So the article respectively makes a nonlinear research on hydrauliccontrol system and hydraulic transmission system of rolling machine.In the hydraulic control part, rolling machine hydraulic servo control system seesthe output displacement of hydraulic cylinder as feedback signal. The paper sets up anonlinear dynamic model of valve control rolling machine hydraulic system. Theoptimal quadratic form theory. In view of the control stability of model referenceadaptive and the difficult determine of adaptive rate adjustable gain, a new controlstructure, with model reference adaptive system as the outer ring and supplementingby optimal quadratic feedback correction as the inner ring, is established. And asimulation model based on MATLAB/Simulink is built. The control method ofintegrated model is simulated. The purpose of adaptive control strategy is that theoutput of control object is asymptotically uniformly converged to the hope output ofreference model. Compared with other adaptive control strategy, the compositionmethod has simple controller structure, strong adaptive ability, high control precision,easy realization of on-line adaptive control, etc. Through a lot of simulation research,the adaptive control system can effectively overcome the influence of time-varyingparameters and has a strong ability of adaptive control.In the hydraulic transmission part, the power bond graph is drawn in rollingmachine tilting hydraulic system as an example. And its dynamic characteristic stateequation is set up. The simulation research is done by using the power bond graphmethod and MATLAB/Simulink software. Power bond graph is a complex systempassing signal in the form of energy. According to this theory, the dynamic process ofa system is a process of redistributing power flow. After the description of power flowcomponents of hydraulic system composition and their relations etc, it can achieve thecomplete and true definition of the system. The method can effectively reflect thenonlinear problems of rolling machine tilting system, such as valve capacity, valveliquid resistance, etc. So it is more convenient for system analysis and more accuratefor the simulation results.