The Research On Control Strategy For Four-wheel Driven Electric Vehicle

In recent years, energy and environmental pollution and the increasing impact of social development make people focus on improving the human environment. Pure electric vehicles as a new energy vehicles, with zero emissions, low noise advantages, have been more and more attention around the world, and it is called green cars. In electric vehicle research and development of many technical routes to electric wheel drive system as the electric vehicle has become a novel research direction of electric vehicles, which because of its perfect control and the wide range of applications by the academic and engineering attention. In this paper, four-wheel independent drive system is for the study, and we focus on multi-CPU Single Chip DSP plus control system of the related research, design and analysis. We select the best control strategy, so that the four-wheel independent drive electric vehicles can have the best power performance and handling stability.This article began with comprehensive research of the background and development of electric cars at home and abroad on research progress. We analyzed electric vehicles in today's relatively high use of several motor characteristics, combined with the characteristics of electric vehicles that a permanent magnet brushless DC motor applications in the superiority of electric vehicles. Then we introduced the structure and operation of the motor-driven principles, derived a mathematical model of the drive motor, and analyzed several features of motor control strategies.Secondly, we analyzed independent four-wheel drive technology on the characteristics of the analysis, combined with this drive motor torque control strategy, proposed vehicle slip control system increases the rate of the torque control strategy. And we have a detailed analysis of the characteristics of electronic differential technology, electronic differential technology proposed specific solutions.Again, above the integrated control strategy, a DSP chip to the top of the controller, AVR microcontroller for the bottom of the controller were the control system of multi-CPU hardware. The main module of a concrete analysis and design, and software process are introduced. Finally, we used fuzzy control in the control system, combined with four-wheel independent drive control strategy, the slip rate on the system, effective control, to make electric vehicles with the best power performance and handling stability. Then the system was simulated by MATLAB,and the simulation results show that:through the use of fuzzy control, slip rate was controlled at the desired ideal range, can met the design requirements.