Vehicle Stability Control Strategy Study And Simulation

Vehicle Stability Control(VSC) is an active safety device, which lets the vehicle run following the driver's intension to prevent vehicle from losing stability. Now, VSC is the international research focus in the vehicle active safety field. With development of control techniques and decrease of control system cost, VSC will replace ABS to be the standard device of modern vehicles. In recent years, VSC gets great development aboard, and is gradually equipped to the moderate and top class cars; while in China, the research in this field is at very beginning. So, to study VSC has great significance for our country and also has broad application prospect.The dissertation pays more attention to how to develop the vehicle stability control system. Based on the abroad achievements in this field, the following issues are discussed: modeling of vehicle stability control system, analysis of the vehicle stability control theory, the design of control logic and evaluating control effect.First, based on Prof. H.B.Pacejka's Magic Formula tire theory, this paper consummates and sets up a full condition tire model in SAE coordinate, and the model for vehicle stability control system under tire adhesion limit is built, which provides us a good vehicle model for simulating vehicle stability control.And then, the mechanism of the Direct Yaw Moment Control (DYC) method enhance curve accelerating (or braking) capability at limiting behavior, improve automobile control stability is explained. This provides the theory for vehicle stability simulation and control.At last, based on vehicle side-slip angle and yaw rate, 3 different kinds of vehicle handling stability controller are designed using variable structure control with sliding mode theory. At Simulink simulation flat, do simulation experiment of the concept car model with the direct yaw moment control and without control; and which control strategy should be apply in different specifically vehicle working conditions, how the vehicle velocity, steer characteristic, control parameters etc. impact the control quality have been studied.The validity and the robustness of the control strategies are proved through the simulate results. Comparing and analyzing the experiment results, it is shown that: on the low adhesion roadβ-control should be the primary as it can decrease the large side-slip angle; on the high adhesion roadγ-control is the best choice because it can restrain the oversized lateral acceleration; on the mid-adhesion road, the right control strategy should be identified by the vehicle responses. By comprehensive considerate the intercoupling relationship between the side-slip angle and the yaw rate, the combine-control strategy's predominance distinctness because it overcome the disadvantages of the large side-slip angle under theγ-control and can't following the ideal yaw rate under theβ-control. Vehicle possesses optimal control stability with the combine-control obviously.The research work of this paper provides the consultable control strategy for further development in vehicle stability control system, meanwhile it also vail to analyze and simulation experiment of the vehicle motion.