| Hydraulic excavator is widely used in construction machinery.Excavator has the advantages of high power and wide application range.However,in the actual working process,the excavator power is affected by many aspects,which makes the utilization rate low.This paper mainly studies the power matching of the hydraulic excavator from the model simulation aspect,builds and simulates the model of the engine,variable pump and working device,which is of great significance to improve the economy of the excavator power matching.The constant power,pressure cut-off and load sensitive performance of variable displacement pump are analyzed.The relationship between flow distribution of LUDV system and excavator load is introduced.In this paper,the principle of swashplate variable displacement pump and LUDV system is analyzed firstly.Combined with the speed characteristics and load characteristics of the engine,the engine power is divided into heavy load,standard operation and light load conditions,and the matching principle of engine and pump and pump and engine is studied.Secondly,the constant power model of hydraulic pump is built in SIM and verified by constant power simulation software.The model of LUDV system is built and verified by the change of throttle valve opening and load that the system flow distribution is independent of load but related to throttle opening.The parameters of the boom,dipper and bucket are set and simulated.The power and torque curves obtained from the engine model are compared with the bench test,and the engine and pump are matched to verify the constant power performance.Thirdly,the mechanical part,hydraulic part and control signal model of the working device of the excavator are established.The parameters of the boom,dipper and bucket are set and simulated.The target value and simulation value of the cylinder displacement are compared,and the simulation trajectory of the working device is obtained.Finally,the throttle controller of the engine is designed.The opening of the throttle is controlled by fuzzy adaptive PID and the power of the engine is adjusted in real time.The model of the power matching system is simulated.The pressure and flow changes of the boom,bucket and stick cylinder are analyzed,and the pressure and flow changes of the hydraulic pump and the engine power are analyzed,through the simulation results,the maximum error of power matching between the engine and the variable pump is 6%,through the fuzzy control of the throttle controller,the energy saving effect of the excavator can reach more than 5%. |
