| Truck cranes are one of the important varieties of construction machinery.They are responsible for the important tasks of lifting and installation.They are widely used in the construction of national infrastructure and water conservancy projects.At present,the hydraulic system of the truck crane generally adopts the traditional anti-flow saturation load-sensing system.As people have higher requirements for crane positioning accuracy,control stability and micro-motion characteristics,safety and low energy consumption,the traditional flowsaturated resistant load-sensing hydraulic system have slow response speed,poor stability,and performance due to their own mechanical characteristics.Shortcomings such as high consumption have gradually emerged.The development of sensor and controller technology has made it possible to replace the original hardware pressure compensation function with electronic control and valve port parameter real-time measurement and control.This paper takes XCMG XCT55 t truck crane hydraulic control system as the research object,and is funded by the national key research and development program "High-pressure multi-way valve for construction machinery" project 3 "Pump and valve coordination pressure and flow compound control type crane multi-way valve"(2018YFB2001203),the pump-valve coordinated composite control hydraulic system is proposed.Use AMESim software to establish the traditional flow-saturated resistant load-sensing hydraulic system simulation model,and verify the accuracy of the simulation model through experiments.Analyze the typical load principle of the crane,propose a multi-mode control strategy with the handle opening signal as the threshold,establish the AMESim simulation model of the pump-valve coordinated composite control hydraulic system,build a test platform and conduct tests to verify the accuracy of the new system.Finally,analyze the energy efficiency characteristics.The research of this subject provides theoretical support and direction for the future development trend of hydraulic control systems of construction machinery,especially truck cranes.The main research work of the paper is as follows:1.First,the research background and significance of this subject are proposed,and then several typical hydraulic control systems for construction machinery are introduced,including load sensing systems,anti-flow saturation load sensing systems,pre-valve compensation load sensing systems,negative flow control systems and positive flow Control System.Theprinciple of the electro-hydraulic control system and the status quo of research at home and abroad are described in detail,and the content and method of the research on this subject are finally determined in view of the problems existing in the current hydraulic control system of construction machinery.2.Analyze the working principle of the traditional flow-saturated resistant load-sensing hydraulic system currently used on truck cranes,and carry out the hydraulic power components,hydraulic control components,actuators,oil and chamber of the traditional anti-flow saturation load-sensitive hydraulic system Detailed analysis and establishment of a simulation model,and then the establishment of the traditional flow-saturated resistant load-sensing hydraulic system AMESim overall simulation model.Build the traditional flow-saturated resistant load-sensing hydraulic system test platform,and conduct tests to verify the accuracy of its simulation model.3.Aiming at the characteristics of slow response speed,poor stability,and high energy consumption of the traditional flow-saturated resistant load-sensing hydraulic system,the pump-valve coordinated composite control hydraulic system is proposed and the working principle is analyzed,and a simulation model is established according to the working principle.The principle analysis of the crane’s typical load is carried out,and the control strategy based on mode switching is proposed for the four quadrants of the crane’s actuator work.Set up the control algorithm model in the micro-motion mode and the compound action mode in Simulink,set up and compile,import the Simulink algorithm model into the AMESim model,and establish the AMESim/Simulink joint simulation model.4.According to the requirements of the new principle,the crane 22-diameter proportional multi-way valve was modified,the pressure compensator in the proportional multi-way valve was removed,the original LS pressure transmission pipeline was sealed,and the double electrohydraulic proportional pump was purchased to make it consistent with the pump-valve coordination.The pressure flow meets the control requirements of the control hydraulic system.Build a multi-way valve test platform and introduce the working principle.According to the control strategy,the Rexroth BODAS controller is selected and introduced,and the control program is written according to the specific requirements of the test.Finally,experiments are carried out to verify the accuracy of the pump-valve coordinated composite control hydraulic system.5.Perform detailed analysis and modeling of the single-action micro-motion mode,singleaction fast motion mode and compound action mode of crane actuators respectively,and perform compound control of the traditional flow-saturated resistant load-sensing hydraulic system,the pump-valve coordinated composite control hydraulic system are simulated.The simulation results show that,compared with the traditional flow-saturated resistant load-sensing hydraulic system,the pump-valve coordinated composite control hydraulic system does not have the throttling loss of the pressure compensator,and the control strategy is improved,which further reduces the system energy consumption.The pump-valve coordinated composite control hydraulic system reduces the system energy consumption by about 2.74% in the luffing unit single-action micro-motion mode,and reduces the system energy consumption by about 9.23%in the luffing unit single-action fast motion mode.The luffing unit and winch unit are combined The system energy consumption is reduced by approximately 10.60% in sports mode. |
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