Research And Development Of Electronically Controlled Hydraulic System For Small And Medium Tractors

In recent years,the electronically controlled hydraulic suspension technology of the tractor has caught the attention from the academic circles and industries throughout the nation.Based on the current development of nation’s suspension technology of the tractor as well as the characteristics of electronically controlled hydraulic suspension system and its application in engineering fields,this paper designs a set of new type of force sensing mechanism for the small and medium-sized tractor hydraulic suspension system to realize the tractor operating force of hydraulic suspension system adjustment,place adjustment and comprehensive adjustment.Secondly,from the principle of electronically controlled hydraulic suspension plow deep control system,this paper puts forward a new type of electric control hydraulic system for the actual process of uping and downing of the plowshares.This kind of hydraulic system is based on valve control system as a whole which mainly focus on the electro-hydraulic proportional valve.It develops the overflow type of flow compensation valve model and carry out the simulation analysis as well as build up valve structure to ensure the process for the stability of plough drop.Thus,it can realize the intelligent electro-hydraulic control.Afterwards,with the aid of AMESIM simulation software platform,this paper establishes simulation model of hydraulic valve block and carry out the parameter settings for it.At the same time,it takes the linear increase of proportional solenoid signal and step signal as tillage depth adjustment control signal and carryout the rise in the system the overflow type flow compensation valve model and analyzes the flow characteristic of the model and influential factors as well as the dynamic characteristics.As a result,this paper gets the curve for the flow and pressure changing with loads and the curve for the linear change of valve port flow curve and transient response curve.The outcome illustrates that the response time of the new electronically controlled hydraulic system transient is short and it also can maintain good stability and high reliability.At last,this paper carries out the simulation of the force feedback condition of electric hydraulic suspension system of tractor and establishes the simulation model of PID control,builds the motion model of suspended plow with the aid of Adams software and analyzes the characteristics of the model,thereby,the force variation curve of the sensor and hydraulic pressure and the cylinder force change curve has been gotten,as well as the hydraulic cylinder displacement and the location of the depth of change curve.It also sets the simulation running parameters and carries out the simulation,getting the actual change of the depth of the curve and the analysis of maintaining its error within 1.7% to meet the practical requirements of the tractor plowing operations.