To enhance braking performance and lateral stability of vehicles equipped with a brake-by-wire system during emergency braking-in-turn maneuver, this paper proposes a Hybrid Optimization Allocation (HOA) strategy for braking force based on a hierarchical architecture. The upper motion control layer utilizes a Two-Degree-of-Freedom vehicle model as its reference and employs the model predictive control algorithm to determine the demand lateral force and yaw moment necessary to maintain vehicle lateral stability. The lower braking force allocation layer, based on the sequential quadratic programming algorithm, divides conventional and limit working conditions and designs differentiated objective functions to realize the hybrid optimal allocation of four-wheel braking forces. Finally, a wheel slip ratio controller is designed to dynamically adjust the target braking force. CarSim/Simulink co-simulation results verify that, compared with the single optimization allocation strategy, the HOA strategy can reduce the braking distance by 1.4~2.56 m while maintaining favorable lateral stability. The Hardware-in-the-Loop test platform is designed to validate the real-time performance and robustness of the HOA strategy.
Deng et al. (Thu,) studied this question.