Study On The Electro-hydraulic Control System Of Working Device For Supersized Hydraulic Excavators

In the union-working of large-scale open-pit mine,the supersized hydraulic excavator is working with large mine tripper to increase production efficiency and replace the middle-small hydraulic excavator.The traditional dual pump and dual valve system has definite relationship with the actuators and its control logic is simple.So it’s not applicable to the supersized hydraulic excavator,which has the featuresof flexible allocation and control.In the independently developed,it is necessary to research the electro-hydraulic control system of the supersized hydraulic excavator.Aiming at the hydraulic system of the working device of 300 tons supersized hydraulic excavator,the single and compound actionswere studied by the methods of mechanical-electrical-hydraulicco-simulation and experiment,also the problems of the control logic and dynamic change of the multi pumps and valves and actuators have been solved,referring to the real principles and parameters.The hydraulic simulation modelwas established based on the study of hydraulic components principle.And the planar mechanism simulation model was established based on the study of hinge joint position and barycenter position and components weights.Also the control system simulation model was established based on the control mode and process.The co-simulation model of the working device was established by combining all simulation models,which would be the research foundation of the control strategy.For the single actions of the bucket,arm and boom,the characteristics of pump control,valve control and pump-valve combination control were simulated,and the simulation results shows that only pump control would cause suction,and only valve control would cause energy waste,and the combination control would avoid these defects.The rodless cavity pressure is always high in the boom cylinder,for this characteristic,the flow regeneration control loop was designed to control the falling speed better and save energy.The control principle of the pumps and valves and actuators was researched in the compound actions of the working device.In order to make the compound actions coordinate,the displacement adjustment coefficient and power adjustment coefficient were set.Also the transition control was set to meet the switch control of different actions.The results of the experiment research on hydraulic system of the work device show that the single actions can be controlled well,the compound actions can be controlled independently and with little interaction,also all actions switch smoothly with the method of the transition control.Through this study,the control frame of the hydraulic system of the working device was established,the single action anddual compound action and three compound action can be controlled effectively with optimized method of pump-valve combination control.With this method,the actions can avoid suction and energy waste and can switch smoothly.Also test result shows that the method established in this paper is effective.