Research On Adaptive Control Of Electro-hydraulic Servo Proportional Force Loading System

The electro-hydraulic servo control system has the characteristics of high stiffness,high power-to-weight ratio and fast response.It plays an irreplaceable role in modern engineering practice.Electro-hydraulic loading control system is an important branch of electro-hydraulic servo system,but the limitation of its system characteristics determines that the control of force control system is difficult.The research of control strategy of force control system has always been a key direction of electro-hydraulic servo control system.Through the study of electro-hydraulic servo control system and adaptive control theory at home and abroad,this paper takes electro-hydraulic servo proportional force loading system as the research background,and studies the adaptive control strategy based on two different control ideas and theories to solve the unmodeled dynamics and other uncertainties of electro-hydraulic servo proportional force loading system.Firstly,based on the mechanism analysis and modeling of the electro-hydraulic loading system,the parameters can affect the control performance of the system are analyzed in time domain and frequency domain.Two adaptive control methods based on different theories are designed,one is model-free adaptive control algorithm based on datadriven control idea and linearization method of compact form dynamic linearization,The other is model reference adaptive control algorithm based on Lyapunov stability theory and positive real transfer function.The simulation results by MATLAB/Simulink software show that the control effect of model reference adaptive control for electro-hydraulic loading system is better than that of model-free adaptive control.At the same time,the two adaptive algorithms are also better than the traditional control methods.But in the design of the controller structure,because the electro-hydraulic loading system is a high-order system,in order to simplify the design of the controller,the mathematical model of the controlled object needs to be reduced and simplified;But model adaptive control,the structure design of the controller does not depend on the controlled object,and the input and output of the system can be directly used to design the algorithm.In order to verify the control effect of the model-free adaptive control algorithm,this paper also designed the measurement and control system of electro-hydraulic servo proportional force loading through LabVIEW software platform.The experimental results show that the control performance of the model-free adaptive control is better than the traditional PID control,and the system can maintain good robustness against time-varying and sudden disturbances.