Study On Independent Metering Control Valve And System

Hydraulic transmission technology plays an important role in the development of national economy,especially in infrastructure equipment,such as construction machinery.Conventional load-sensing system can better adapt to the coordinated action of multi-actuator motion mechanism,but there is always excessive throttling loss caused by the solid connection structure of conventional multy-way valve.One solution to this problem is to use two or more valves to control actuators,called independent metering control.Currently,the study in this field mainly focuses on the energy-saving effect of the hydraulic system,the selection of working mode of the actuator and the compound control strategy of speed and pressure.Although the related studies show that this system has better performance,but there are not many applications in practice at present,mainly because the cost of system design is much higher than the existing technology,and the control performance of multi-actuator compound action in the actual operating environment is still to be tested.Aiming at the problems existing in the current technology of independent metering control,this paper creatively combines the traditional load-sensing technology with the independent metering control technology.At present,there are few studies on the post compensation for the unit of load port valve group.An independent metering control valve with the pressure drop compensation function behind the valve is proposed.In order to overcome the drawback of long pipeline pressure transmission in the traditional hydraulic load-sensing system,the pressure drop compensation function put forward in this paper is realized by electronic pump.This pressure drop compensation function can greatly simplify the structure of the independent metering control system installed with many pressure sensors,and can adopt the open-loop control of the traditional load-sensing hydraulic system to the actuators without the requirement of accurate speed control,and realize the noninteraction of actuators under the condition of flow-saturation.Firstly,this paper introduces the principle of conventional load-sensing system which is widely used in the hydraulic system of construction machinery,summarizes the advantages and disadvantages of these systems,and provides the basis for the subsequentsystem design.Then it introduces three kinds of independent metering control systems which are widely studied at present,and puts forward a new type of independent metering control system scheme on the basis of these systems research.Secondly,in order to improve the performance of the main valve in the valve group unit,the AMESim-MATLAB/Simulink mechanical and electro-hydraulic cosimulation is carried out.In order to improve the simulation accuracy,the flow field characteristics of the main valve and the current characteristics of the proportional solenoid drive circuit are studied.Then,the position control strategy of the main valve is studied,and the position control of the main valve is simulated by using fuzzy PID and neural network PID.Then,the characteristics of the independent metering control system proposed in this paper are studied,and the speed and pressure control strategy,energy conservation effect and anti-flow-saturation of the system are simulated.Finally,the energy consumption of the conventional load-sensing hydraulic system and the independent metering control system is compared,and the anti-flow-saturation function of the system is tested.