The Hydraulic Control System For An Asymmetric Cylinder Based On Dual-constant Pump Driven By Dual-servo Motor Respectively

In recent years,more and more research of pump control system are conducted since it is more energy saving than the valve control system.For the pump controlled asymmetric cylinder system,in order to solve the problem of flow balance between the two chambers of the cylinder,people have put forward solutions such as oil supply circuit,special pump driven by single motor and dual-pump or multi-pump system.In the research of the asymmetric cylinder driven by dual-pump,the pump / motor unit is mainly used,and two-way linear motion are realized by motor reversing.In this paper,a hydraulic control system for an asymmetric cylinder based on dual-constant pump driven by dual-servo motor respectively is proposed.According to the designed hydraulic schematic diagram,the system has the characteristics of small power loss and high efficiency.Since the independent "servo motor + constant pump" is used to supply oil to the two chambers of the asymmetric hydraulic cylinder,there is no electromagnetic valve used and no need for the servo motor to reverse to realize the two-way line motion.This is realized by two two-position threeway valves directly controlled by the outlet pressure of the constant pump,so the system response speed is high,so is the control accuracy.The overall structure design of the system and the design of the hardware control system are completed based on the hydraulic schematic diagram.Secondly,the mathematical model of the control system is established,the transfer function of the system is deduced,and the steady-state and dynamic characteristics of the system are preliminarily analyzed.Then,through the co-simulation of AMESim and MATLAB Simulink,the feasibility of the system is verified,its mechanism is further studied,and the parameters of major hydraulic components are determined,which provides theoretical support for the test.On this basis,the control strategy and control method are studied.At last,the prototype is completed,and the test results are analyzed.In this paper,through the combination of theory,simulation and experiment,it is proved that the hydraulic control system for an asymmetric cylinder based on dual-constant pump driven by dual-servo motor respectively is feasible.The results of the three supports each other.The parameters of hydraulic components obtained by theory and simulation have achieved good results in the experiment.Through simulation and test,it is proved that the system designed in this paper can achieve high-precision positioning control under PID control,and show the characteristics of fast response and good stability.