Research On Constant Speed Control System Of Electric Tractor Based On Sliding Mode Variable Structure

Energy and en Vironmental issues ha Ve recei Ved wide attention from Various countries.Countries around the world ha Ve successiVely proposed a timetable for the ban on fuel Vehicles,and plans to fully introduce electric Vehicles.Intelligent control of electric Vehicles is one of the hot topics in the field of agricultural engineering.This subject is mainly to conduct an in-depth study on the constant speed intelligent control system for electric tractors.The purpose is to reduce the labor intensity of the dri Ver and improVe the quality of the work in order to meet the requirements of the field conditions.First,modeling and simulation of the whole Vehicle model of electric tractors.According to the structure of the tractor,the main functional parts were selected,and the kinetic equations were used to perform the modular mathematical model of the battery,motor,dri Ve train and dri Ve wheels.The model of the electric tractor body was established by using the method of related parameters between the modules.Through Matlab/Simulink modeling and simulation of the Vehicle mathematical model,obser Ve the changes in the speed of the motor and dri Ve wheel under the circumstances of changes in the external load,Verify the rationality of the model establishment,and pro Vide the basis for system adjustment.Second,research on methods of constant speed control strategy for electric Tractors.In View of the singularity and deri VatiVe discontinuity of the control system,an adapti Ve constant-speed decision-making control algorithm based on the Terminal Sliding Mode Variable Arithmetic is proposed.Taking the Vehicle speed as the goal,the “linear + nonlinear” sliding mode surface is adopted,and the terminal sliding mode Variable control function is designed to adjust the adapti Ve law online.In the case of outside interference,the tracking error con Verges to zero within a limited time,effectiVely impro Ving the constant speed.Controller control quality.Compared with PID algorithm,Matlab/Simulink simulation is used to compare the control accuracy and response time of the two.Third,the hardware takes the DSP processor as the core,selects the appropriate sensor to collect the signals such as Voltage,current,speed and torque of the control system,sends the data to the DSP,and feeds back the adjustment signal to the motor.Using CCS software to program the system main program,initialization,interrupt ser Vice routines,adapti Ve terminal sliding mode subroutines,etc.Four,test bench construction.The test stand is mainly composed of power supply module,motor and motor controller,gearbox,Vehicle controller,magnetic powder brake and load controller.Off-line calibration speed,designing three test schemes of no-load,load-carrying and simulation load,Verifying the rationality of the whole model of the electric tractor and the reliability of the control strategy.