Control Method Research On The Electro-hydraulic Proportional Pump-controlled Motor Speed System

Thanks to the high efficiency and long lifespan, the proportional pump-controlledmotor system is widely used in the field of huge power. With the development of themicrocontroller and intelligent control theory, more and more control methods whichhave complete theoretical system are applied to the practical applications. In order toimprove the static and dynamic performance and the ability of anti-disturbance of thepump-controlled motor system further, the author explores the system structure andcontrol algorithm in the view of control theory.Based on the entirely expound about the development status of electro-hydraulicproportional control technique, the thesis analyses the characteristic of thepump-controlled motor speed system and gives the design of the general planning. Later,the thesis analyses the operating principle and give the Drawing of oil circuit based ondetermining each structure of the control system.After a force analysis on the swash plate of the axial piston pump, the thesiscalculates the value of moment in different situations. The whole mathematical model ofthe pump-controlled motor system is deduced according to the working principle of theproportional valve-controlled cylinder, variable pump and hydraulic motor. The systemmodel is built in Matlab/Simulink. And the influences of step input, load torque andvarying input pump speed are analyzed.Based on the characteristics of the pump-controlled motor speed system, thetechnique of ADRC control, which is has little relationship of system model, is studied.Later, a hybrid ADRC controller with load torque and speed disturbance feed-forwardcompensation is proposed.Compared with the traditional PID and ADRC controller, the hybrid controller hasan effective suppression to the uncertain system parameters which is caused by thecompressibility of the fluid and nonlinearity. The control results show the proposedcontroller possesses a great static and dynamic performance. Moreover, it also has anexcellent rapidity and robust as the load torque and input pump speed change suddenly.Finally, a digital hardware circuit is designed for the pump-controlled motor controlsystem. It is mainly contained of the proportional driver, the detection of the swash plateposition, the speed measurement circuit.