Research On Combined Control Strategy Of Active Anti-Roll Bar And Differential Braking For Handling Stability

With the improvement of Chinese automobile industry and highway construction technology, vehicle is playing a very important role in our daily life and people would like to pay more attention to the vehicle’s performance, such as handling stability and active safety, besides of the vehicle’s fuel economy, ride comfort and passive safety etc. Therefore, how to avoid the occurrence of the traffic accident and keep the vehicle running smoothly in high-speed have become the current concern issues in the domestic of foreign automobile manufacturers and research institutions. The research on vehicle handling stability would be carried on the combined control of active anti-roll bar and differential braking system, in order to solve the driving stability problem in this paper.For the research on active anti-roll bar, this paper described a design of a dual motor drive type active anti-roll bar based on the analysis of the traditional passive anti-roll bar, and got the control variables of active anti-roll bar based on the established vehicle model, and got the vehicle ideal roll angle curve of lateral acceleration through the continuous treatment of MATLAB. Through processing the vehicle model, a simplified mathematical model of active anti-roll bar controller would be got, which would be combined with the vehicle dynamics constraints, control variable constraints and output constraints to complete the design of the active anti-roll bar controller.In the study of differential braking control system, we finished the analysis of the optimal control of tire slip ratio and the influence of single wheel brake to the vehicle’s stability, and then made the differential braking control strategy based on the above theoretical. Through the analysis of the linear 2 DOF vehicle dynamics model, we obtained the ideal value of control variables and the vehicle steady state criterion, which would be combined with the nonlinear dynamics model and a series of constraints to complete design of the differential braking system controller.The coordinated control strategy would be used in the combined control system, according to the features of both two systems. And based on the design of controllers’ structure, the MATLAB language would be used to program the two controllers in S-function environment which were all based on model predictive control theory, and the control target and coordinated control strategy of the combined control system would be given finally.After all of the above, CarSim and Simulink were used to build the joint simulation platform. The active anti-roll bar control system and the differential braking control system and the combined control system would be test respectively under the curve braking and double lane change manoeuvre. Through the comparison analysis of the simulation results, the combined control system compared with the single control system, can more effectively solved the vehicle roll problem, while suppressing the vehicle lateral sway, which could improve vehicle handling and stability impressively.