| With internal combustion engine as the power sources of supply, Conventional vehicles emission a lot of exhaust to the environment and pollute the environment. With the EV-related technology innovation, the EV as a green new energy vehicle is gradually replacing the conventional vehicle. Now the vehicle has been mature, which is produced only by replacing the original car engine electric cars with motor. The major domestic and foreign manufacturers have begun to produce its own brand of the electric vehicle to market. However, the final form of the electric car should not be a simple alternative to the internal combustion engine, but a new fully form of electric vehicle for motor own characteristics. This new fully form of electric vehicle is the four wheel independent steering and driving electric vehicles. in order to fully enhance the performances of the vehicle, the 4WISD EV from the structure to the control of vehicle is fully considering motor own characteristics.In order to really put this new electric vehicle into practice, from the engineering point, this paper chose in-wheel SRM as driving motor and designed the hardware and software systems of the vehicle; from the theoretical point, this paper established a steering wheel independent drive electric cars linear four wheel model, proposed an four-wheel-optimal synchronization control algorithm for the 4WISD EV, and built the 4WISD EV simulation platform. In this paper, the proposed algorithm was simulated on the typical vehicle operating conditions.In the process of the hardware and software design, this paper designed the vehicle system by the means of "bottom-up" design. Firstly, combined with the design requirements and the situation of our teaching and research section, this paper chose the electric vehicle battery management system, drive systems, steering systems, sensor modules and so on. Most modules are developed in our teaching and research section, while part of the module also applied for a national patent. During the design process, various redundant designs improved the system fault tolerance. The vote design ensured the reliability of control. The failure minimum operating circuit design ensured that vehicles can travel in fault mode when some parts have problems. Finally, this paper based on the vehicle controller hardware design, selected uC / OS embedded operating system as the software platform, reasonably divided control signal acquisition task, signal processing task, state estimation task, coordination control task and were reasonable division of tasks and set their priorities. Otherwise, this paper gave some explain about the way of the information synchronization between inside tasks.In the process of algorithm research, this paper referred to the traditional linear two degree of freedom vehicle model and established 4WISD linear four-wheel model. In view of the different electric vehicle driving speed, this paper respectively designed low speed mode flexible control algorithm and high speed stability control algorithm. For high-speed stability mode, this paper based on zero sideslip angle of centroid proposed 4WISD EV synchronous optimal control algorithm. The algorithm can guarantee the stability of the vehicle, while improving the efficiency of travel of the vehicle. The 4WISD EV simulation platform was also set up in this paper. By modifying traditional car simulation model in Carsim, we could use it to simulate 4WISD EV in Carsim. Importing the above model to Simlink, 4WISD EV on typical of the vehicle work conditions was simulated. |
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