The Research On Dynamic Characteristics Of Leveling Hydraulic System Of Asphalt Pavement Milling Machine

Asphalt pavement milling machine has the advantages of high efficiency,simple construction,easy control of milling depth and good operability.It is widely used in asphalt pavement maintenance engineering.The working characteristics of the leveling hydraulic system of milling machine have significant influence on the performance of the leveling system.In order to level the system performance,this paper studies the dynamic characteristics of the leveling hydraulic system of milling machine.This paper studies the leveling control principle of asphalt pavement milling machine,compares and analyzes the characteristics of side sliding plate leveling system,ultrasonic sensor leveling system and laser sensor leveling system of asphalt pavement milling machine.It also analyzes the speed difference of hydraulic cylinder of leveling hydraulic system of milling machine when it is in transition and operation,analyzes the speed load characteristics of leveling hydraulic system with different speed regulation forms,and studies the speed load characteristics of leveling hydraulic system In the plan of flat hydraulic system,the parameter calculation and selection of hydraulic components are completed.The flow equation of slide valve,the flow continuity equation of hydraulic cylinder and the force balance equation of hydraulic cylinder and load are derived.The simulation model of the leveling hydraulic system of the milling machine is established.The dynamic characteristics of the hydraulic system are modeled and simulated in Simulink / simscape.The dynamic characteristics of the automatic leveling system of the milling machine are tested by using the design parameters.The results show that: the leveling hydraulic system has a good response to the slope signal,step signal and sine signal,but there is a certain time delay;it has a good leveling effect on the low-frequency road surface roughness change in the milling machine operation process,and can improve the leveling flatness under the condition of no difference control in the side slide plate square finding method;it verifies the hydraulic system fluid of the milling machine The rationality of the difference setting of the velocity value of the cylinder in the transition and operation is reasonable.The rationality of the hydraulic system design scheme and hydraulic system parameter setting is verified.