| Electronic Stability Program (ESP) is an advanced active safety device, which is based on the anti-lock brake system (ABS) and traction control system (TCS). It can actively inhibit the car over-steer and under-steer, and comprehensively improve the vehicle handling and stability when driving and safety.A seven-degree-of-freedom yaw plane vehicle model based on the H.B.Pacejka tire model has been built in this dissertation. The vehicle model includes the longitudinal, lateral, yaw orientation and four wheels whirl. Through the analysis of Electronic Stability Program, the yaw rate and sideslip angle which are the two important parameters of vehicle driving stability are determined the control objectives and the yaw rate and sideslip angle of the nominal value is determined. The control wheel is selected and in based of this electronic stability control system structure is established. Based on fuzzy control theory, the yaw rate and sideslip angle controller are established, and a logical model of controlling wheel is built in Matlab / Stateflow. Finally, the controller model and vehicle dynamics model are combined and simulated through the front wheel angle step input and sinusoidal input in the slippery road surface using typical operating conditions. By using of the hardware in the loop simulation system dSPACE to carry out the slalom test with the outside signal source, and the results of the simulation has been analyzed.Results indicated that, the control systems with the target of yaw rate and sideslip angle had good control, improved vehicle handling and stability. The controller real-time simulation speed of response is sensitive, and it has good effect on automobile stability with the different outside entering and off-line simulation results are approximately the same. The realization of on-line simulation has established a basis for further accurate model building up and the improvement of control strategy, and it is a technical support to the code compiling of ECU. |
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