Research On High Performance Pressure Control Strategy Of Electro-hydraulic Servo Pump Control System

The electro-hydraulic servo pump control system is a servo control unit that is highly integrated with servo motors,hydraulic pumps,hydraulic cylinders,and functional valve groups.Compared with traditional valve control system,it effectively overcomes the inherent technical defects of valve control systems such as large throttling loss and poor pollution resistance,and has technical advantages such as high power to weight ratio,high efficiency,energy conservation,and environmental friendliness.However,the integration of electrical,control,hydraulic,and mechanical components in the electro-hydraulic servo pump control system creates a volumetric servo drive solution,which poses many challenges for the high-performance operation of the system.Among them,the driving motor serves as the core control inner loop of the system,and the interference of factors such as nonlinear motor speed,ripple torque,and motor parameter uncertainty on the control performance of the motor will directly affect the pressure control effect of the outer loop of the pump control system;In addition,the uncertain internal and external interference in the hydraulic system,as well as system nonlinearity(flow nonlinearity,friction nonlinearity,etc)factors,result in low static accuracy and limited dynamic performance of the system control.These technical difficulties limit the promotion and application of pump control systems in the industrial field.Therefore,this article will conduct research on the pressure control strategy of the electro-hydraulic servo pump control system,with the aim of improving the system control performance.Firstly,the mathematical and simulation models of electro-hydraulic servo pump control system are established.Based on the working principle of pump control system,the mathematical models of driving motor system and hydraulic system are established.The simulation models of motor and hydraulic part are built by using MATLAB/Simulink software,which lay the theoretical and simulation foundation for the research of pressure control strategy of pump control system.Secondly,an adaptive sliding mode torque control strategy for motor is proposed.To solve the torque ripple problem existing in traditional direct torque control(DTC),vector modulation(SVPWM)is used instead of traditional switching table to improve the electromagnetic torque ripple.Aiming at the problems of nonlinearity and uncertain parameters of motor,the adaptive sliding mode torque controller is studied and optimized with reaching law to achieve high performance control of motor,and the effectiveness of this strategy is verified by simulation.Furthermore,a torque compensation active disturbance rejection pressure control strategy based on torque direct drive is proposed.Aiming at the problems of high nonlinearity and uncertain disturbance in the pump control system,a torque compensation active disturbance rejection pressure control strategy is proposed by taking advantage of the advantages of fast dynamic response of the motor torque ring.The disturbance observation and control compensation are carried out on the system.The flow leakage is compensated by the model prediction torque compensation strategy.And the simulation platform is used to verify the high performance control characteristics of the strategy.Finally,the pump control system pressure control experimental platform is built and related experimental research is carried out.The torque compensation active disturbance rejection pressure control strategy based on torque direct drive is verified by the pump control experimental platform.The experimental results show that the high performance pressure control strategy proposed in this paper can effectively improve the control precision and response speed of the pump control system,and the feasibility and effectiveness of the high performance control strategy are further verified.