Development Of Electronic Control System For The Automatic Transmission Of Electric Vehicles

Automatic transmission plays an important role in reducing fuel consumption and improving exhaust emissions.At present,the electric vehicle transmission in the market is mainly a single-speed transmission,and its power and energy consumption are somewhat limited by a certain degree.Therefore,it is very necessary to develop a new type of electric vehicle transmission.This paper is based on the current situation of the development of modern electric car automatic transmission,combining the theory of vehicle design and electronic control technology,the key to design a new type of automatic transmission of power transmission line,the parameters of the main components of matching,the electronic control system development and so on has carried on the related research work.First of all,the structure,working principle and the transmission route of each file of the new automatic transmission are briefly described.According to the requirements of the complete vehicle power,the selection of the driving motor,shift motor and screw drive are completed,the gear position of the transmission and transmission ratio are determined..Secondly,the automatic transmission shifting system is analyzed,and the shifting motor,screw nut,etc are modeled and simulated.A two-parameter dynamic shift law is formulated,a shift strategy based on the control of the driving motor speed and the accelerator opening is proposed and a shift point is obtained.The simulation models of the drive motor and the electric vehicle are built in MATLAB and respectively.The simulation of the shift system and the main driving force transmission system shows that the shift control strategy has a good shift effect.Based on the main control chip DSP56F8346,the hardware circuit diagrams such as the acquisition speed signal and the accelerator pedal signal are drawn and the software system is designed according to the control strategy of the developing transmission.Finally,this paper acquisites the signal and tests transmission system of hardware and software to verify the validity of the developed electronic control system.Firstly doing shift test on the bench,and then doing the speed signal in a laboratory,the opening of the accelerator pedal signal acquisition experiments.The experimental results meets the needs of this transmission control system and lays a solid foundation for the further experiment of late real vehicle tests.