Research On Auxiliary Drive Control System Of Front Axle For Mining Trucks

The mining trucks is used as an important tool for earthwork transportation,and is widely used in industries such as mining,metallurgy and construction.It has a relatively sophisticated driving condition.Because it can't avoid driving in a working environment with low adhesion coefficient of snow,dry sand and mud,it has a high requirement for driving property.The existing all-wheel drive technology can improve the driving property of mining trucks,but there are still obvious defects such as increased tire wear and lower fuel economy.Therefore,based on the original driving form,this paper added the front axle auxiliary drive system composed of variable pump,hydraulic wheel hub motor,energy accumulator and hydraulic control valve group.This paper first analyzes the advantages and disadvantages of common forms of hydraulic drive,and then use the method of directly hydraulic wheel hub motor driven,analysis the power producer of hydraulic system and the installation location of power take off,and match the key components of hydraulic circuit model parameters,to ensure that meet the functional requirements of hydraulic system.Secondly,this paper establishes the mining truck's whole vehicle dynamics model and mechanical transmission system model in the Simulink environment from the perspective of system dynamics,and set up the hydraulic transmission system model in the AMESim environment,realized the establishment of system joint simulation platform through the creation of data communication interface.In order to achieve the mining truck front axle condition's identification of auxiliary drive system correctly and coordinate with the whole main driving wheel after the opening of auxiliary drive system.This paper uses the control strategy of front wheel speed follows the rear wheel speed.In Simulink,the switching logic of auxiliary drive system and the speed control method of hub motor are established.In the variable pump-wheel hub motor power mode,the PID based on look-up table method for variable displacement pump control,the power accumulator-wheel hub motor power mode adopts PID control to control accumulator output flow,thus realize the speed control of front wheel.In order to realize the correct identification and mode switching of the mining trucks working mode,this paper makes a comprehensive judgment by obtaining the driver control signal,the mid wheel and rear wheel slippage rate of the mining trucks,the hydraulic signal of the power accumulator,the gear signal and the wheel speed signal.The vehicle state equation,vehicle observation equation and the Unscented Kalman Filter(UKF)algorithm can estimate the vehicle speed and accurately calculate the slippage rate of the rear wheel.Finally,this paper simulates the typical work situation of mining trucks.A simulation analysis is carried out on the front wheel speed of the variable pump-wheel hub motor assisted mode and power accumulator-wheel hub motor.And this is a simulation of the switching logic of the work mode of the front wheel auxiliary drive system,which proves that the control strategy controls the front axle of the mining trucks to drive the auxiliary drive,the brake energy recovery,and the free wheel and the work needs.And verifies that the auxiliary drive system of the vehicle front axle improves the driving property of the vehicle in the auxiliary drive mode.Download the code generated by the operating mode switching model and the auxiliary drive system control strategy model to the Arduino DUE,conducts the controller's in the loop test,compares the simulation results,and verifies the feasibility of this system.