Research On The Characteristics Of Hydraulic Excavator With Speed Variable Power Source And Separate Chamber Control System

Hydraulic excavator is one of the most widely used mobile machinery.Due to complex work environment,large changing range and frequent changing of the load,the engine often works in low efficiency area which causes low energy efficiency and poor emission.Moreover,the multi-way valves are used as control elements for power distribution,resulting in severe throttling loss and further increasing the energy consumption of the excavator.In all output power of diesel engines,only 20% of the power is applied to the actual work of the actuators.For the global energy crisis and environmental pollution become more and more prominent,the problems of large energy consumption and poor emission of hydraulic excavators need to be solved urgently.Thus,how to realize the energy saving and emission reduction of hydraulic excavators is always a research hotspot for many years.At present,although the energy efficiency of hydraulic excavators has been improved to a certain degree by using the hybrid power source and electrohydraulic load sensitive control technology,the inherent characteristics of diesel engine and four side linkage multi-way valve restrict the development of energy saving and emission reduction of hydraulic excavators.In order to solve the above problems,this paper uses a constant pump driven by servo motor as a speed variable power source integrating with separate chamber control technology to control hydraulic excavator.The energy efficiency of hydraulic excavator power source is improved by using the pure electric drive technology,which can avoid the pollution of the diesel engine exhaust emission.Furthermore,the throttle loss of the hydraulic system is reduced by using the separate chamber control technology.A flow matching control strategy based on pump and valve coordination is designed.The operation and energy consumption characteristics of the hydraulic excavator are studied.The specific research contents are as follows:Firstly,through the analysis of the characteristics of different power sources and hydraulic circuits,the AC permanent magnet synchronous servo motor driven constant pump is selected as the speed variable power source and the separate chamber control system is selected as the hydraulic control circuit.Based on the mathematical model of the AC permanent magnet synchronous servo motor and separate chamber control system,the process of the motor based on the vector speed control method and the energy consumption characteristics of the separate chamber control system are analyzed,which provide theoretical guidance for the simulation model construction and analysis of the proposed system.Secondly,a multi-body dynamics model of the hydraulic excavator mechanical structure is built in SimulationX.Then,according to the working principle and parameters of the actual servo motor,the simulation model of the permanent magnet synchronous servo motor speed control system is built.Then the simulation model of the hydraulic control circuit is built based on the principle of separate chamber control.On this basis,the co-simulation model of the hydraulic excavator with speed variable power source and separate chamber control technology is built.The accuracy of the servo motor and the whole machine simulation model is validated by comparing with the test dataFinally,a flow matching control strategy based on pump and valve coordination is designed.The operating characteristics of the hydraulic excavator actuators during the single action process,compound action process and excavation process are analyzed through simulation and experiment.Under the same operating conditions,the power sources and whole machine energy consumption characteristics of the proposed hydraulic excavator system and the traditional flow-saturated resistant(LUDV)hydraulic excavator system are compared and analyzed.The research results show that,by using the speed variable power source and separate chamber control technology combined with the flow matching control strategy based on pump and valve coordination,the hydraulic excavator maintains good operating characteristics during the single action process,compound action process and the excavation process.Compared with the LUDV hydraulic excavator,the hydraulic system energy consumption of the hydraulic excavator with the proposed system is reduced by 32.9%,and the operation cost of the whole machine is reduced by 59.4% during excavation process,which significantly improves the energy efficiency of the hydraulic excavator.