Research On Electric Differential Control Of Two Wheel Drive Electric Vehicle

From the perspective of features of motor drive, Multi-motor-driven EV gets rid of shackles of the traditional internal combustion engine vehicles in terms of structure and plays the advantages of electric drive fully. Multi-motor drive is the core technology of EV comprehensive industry, which changes the traditional energy alternation on the auto chassis to an overall and revolutionary improvement which is from structure to energy and from drivability to handling capability.Electronic differential(ED) technology replaces the traditional automobile miscellaneous mechanical differential device through the coordination of multiple motors, which is the key technology deal with accurate vehicle steering and good handing. The thesis discusses the differential control of dual drive motor with EV of front-wheel drive two-wheeled motor. The main work of the thesis is as following:Firstly, adopting induction in-wheel motor Direct Torque Control(DTC) as traction control strategy of single motor according to the drive characteristic of EV, analyzing the Direct torque control system in theoretical based on the induction motor state equations and simulating the traction performance based on computer simulation deal with various kinds of drive. The simulation results verify the control strategy which further laid foundation of study of differential.Secondly, constructing a virtual master-slave control strategy and compensating left and right wheel motor speed two-way dynamically, base on feed-forward and feedback control theory deal with the problem of Ackermann differential model encounter poor road conditions and difference of left and right wheel drive motor load. Simulation result shows that the control strategy can realize the vehicle steering differential, with a good load tracking performance. Slip ratio is an important parameter of featuring vehicle performance, so the three degrees of freedom EV mathematical model is established. The thesis simulates with different road condition and direction changing of EV and analyzes the impact of various driving conditions and slip ratio on the vehicle handling and stability.With the target of slip ratio, adopting sliding mode control and distribute drive motor torque dynamically deal with the differential of the vehicle and using recursive least squares (RLS)method under different road conditions to online identification to get the best slip ratio in a bid to ensure the best steering precision. Simulation result shows that the algorithm can realize the dynamic allocation of torque to overcome the factors due to road vehicles out of control.Finally, designing debugging motor drive control system, system control circuit, drive circuit and traction control program based on the TMS320F2812. Designing the PC monitoring platform by LabView to send real-time command and monitor the state of motor. Experimental results demonstrate the traction control and the feasibility of Ackermann steering model...