Study On The Electro-hydraulic Proportional Control System For Loader Operating Devices

Currently there are many domestic loaders are equipped with a manual hydraulicpilot control multi-way valve, but its hydraulic lines are many and long, laboriousmanipulation, less efficient and low level of automation. In order to improve themaneuverability of the loader operating devices and improve the automation degreeof its manipulation. The subject for the electro-hydraulic proportional control systemwhich widely used in construction machinery, take5T loader for example, on thepremise that loader operating devices use the manual hydraulic pilot control as maincircuit, electro-hydraulic proportional pilot control replace the manually operatedhydraulic pilot control section.Firstly, by analyzing the composition characteristics and the functionrequirements of the electro-hydraulic proportional control system for loader operatingdevices, completed the overall design of the system; followed, finished selectingcontrol handle, the boom cylinder and the bucket position sensor; then, according tothe manual pilot system parameters, functional requirements and the system works,completed electro-hydraulic proportional pilot ported body and controller design, thedesign of the controller hardware circuit part: microcontroller AT89S52as the core,designed the signal filter circuit, the A/D conversion circuit, MCU control circuit,D/A conversion circuit, signal amplification processing circuit and the signal selectoutput circuit. Software section adopt the modular design: designed the main program,A/D conversion subroutine, data filtering subroutine and data processing subroutine.Finally, by the type tests to verify the performance of the designed theelectro-hydraulic proportional control system for loader operating devices, With theexperimental data of the original manual pilot system of comparison, the performanceof the operation control in the system achieves the desired control effect: Afteradopted electronic control handle, the operating force is reduced significantly, theoperator’s work intensity is reduced also, Operating comfort become better; Under themaximum engine speed, the boom lifting time in fully loaded, the fall time innon-load and the unload boom times are far less than the measurement in the originalpilot system, not only save the working time, but also improve the work efficiency.The architecture of the electro-hydraulic proportional pilot control system forloader operating devices is simple in this article, the control components is fewer, The output of control handle are electrical signals, depending on the different operationalrequirements of the controller to design, to maximize achieve the control functions insoftware, it has a large room for improvement, make no changes in the mainhydraulic system of the loader operating devices, Installation and adjustment isconvenience, You can also implement remote operation control, To achieve intelligenthigh-end loader to lay the technical foundation.