Analysis Of Agricultural Tractors Rear Hitch Hydraulic Control System

As a key component for the quality of ploughing work,the rear hitch control system controls the up and down movement of tractor mounted implements. The dynamics of a tractor-implement combination were complex in the atrocious working environment and fluky work status. A lot of components were not assured. The system had an evident nonlinearity problem about large inertial and response lag due to its machine and hydraulic structure.These characteristics were hard to describe by using exact mathematic model.It was difficult to study unit’s integrated control by using classic control theory relying on exact mathematical model, or modern control theory relying on status function. About integrated control problems and optimal matching methods on plough implement unit, as an example in this paper,were discussed using fuzzy-PID control theory.Ensure that the engine is working at best state for improving the Productivity, economy in fuel, intention in operations and quality.Firstly,based on the analysis of tractor rear hitch hudraulic system,the simulation model of tractor rear hitch hudraulic system and soil resistance are built by using AMESim and the mathematical relationship of traction resistance and tillage depth is built. The range of traction resistance is determined with the analysis of traction efficiency curve.The Fuzzy-PID controller is built based on the rear hitch parameters and used in the control of electronic hydraulic hitch system combining with force position control system. Using the AMESim and MATLAB analyze the performance of the control system.Giving attention to the traction resistance and quality,this paper put forward a force position control strategy with automatic adjustment coefficient,whitch can improve the adaptability of complex working environment,traction efficiency and oil consume economic. Carrying out the simulation and analyzing the control strategy,the force position control strategy with automatic adjustment coefficient which will be used in the rear hitch system is feasible and has a better adaptability.This control strategy also reduce the operating intensity of the driver.