All Wheel Drive System In Motor Grader And Its Control Theory Research

The research of traction dynamics of construction machinery has entered the eraof hydraulic traction dynamics, aim at boosting the traction performance in daily worksituations to improve the adaptation to complicated working situation and satisfy theoperational automation. Add front wheel double-pump and double-motor hydraulicdrive system to the rear wheel drive motor grader can improve the grader tractionpower, through different control mode can make the grader to meet different operationdemands.Double-pump and double-motor front wheel drive system, as a true sense of thehydraulic drive system, its research is focus on the matching of the hydraulic systemand the prototype structure as well as the control algorithm using base on the variablespeed engine. Article manifested that the front wheels of a grader using double pumpand double motor drive、 time-varying nonlinear system is a complex systems withmultiple input and multiple output. Classic control theory is difficult to meet thecontrol requirements. Due to the resulting complex multi-variable hydraulic drivecontrol problems, we simplify the system from theoretical perspective, research on thehydraulic system pressure changes in independent control loop under different loads,combined power control and engineering practical ideal transmission control structure,put forward a modern control strategy in front wheel hydraulic driving system.Based on the specific mechanical structure and hydraulic system of mechanicalgrader prototype, designed front wheel hydraulic drive system, from the systemstructure, hydraulic system analysis to the demand of control system are introduced indetail in this paper.The kinematics and dynamics of grader are analyzed in this paper, nonlinearmathematical model based on the existing variable pump and fixed-displacement motorsystem is established. Using simplified the system as a load torque step input and fixeddisplacement motor model, a double-pump and double-motor system control structurewas putted forward to this multiple parameters, time-varying strong disturbance system.The pump motor system based on fuzzy control theory and computer simulation modelwas built In the Matlab/Simulink software, the control method is simulated, betterdynamic and static performance are obtained, which shows that the method ispracticable.This paper introduced grader AWD hardware debugging and testing methods based on the control method mentioned above, and recorded test results of typicalworking conditions by data acquisition instrument, the analyzed test results shows thatthe control method can satisfy the control requirements.The methods of structure design and control of all wheel drive system describedin this thesis also have reference value to adaptive control and other modern controlmethod research in vehicle hydraulic drive system.