Coordinated Longitudinal-Lateral Stability Control for Vehicle Emergency Braking Based on Stability-Margin Scheduling and Dynamic Weight Allocation

Abstract

This paper proposes a hierarchical coordinated control strategy for improving vehicle stability during emergency braking on split- $\boldsymbol{\mu}$ roads. A $\boldsymbol{\beta}$-r stability-margin-based dynamic weighting mechanism is developed to adaptively coordinate longitudinal braking efficiency and lateral stability. The upper-layer controller employs a linear time-varying model predictive controller (LTV-MPC) to generate the desired additional yaw moment, while the lower-layer controller formulates wheel brake-force allocation as a quadratic programming (QP) problem under friction-ellipse and braking-capacity constraints. The optimization weights are continuously adjusted according to the stability margin, path-deviation risk, and tire-force capacity, enabling a smooth transition from braking-oriented to stability-oriented control. Co-simulation using MATLAB/Simulink and CarSim is conducted under straight-line and steering-braking maneuvers on split- $\boldsymbol{\mu}$ roads. The results show that the proposed method significantly suppresses yaw rate, sideslip angle, and lateral deviation while maintaining comparable braking performance. Compared with benchmark controllers, the proposed strategy achieves superior path-following capability and enhances vehicle directional stability under severe asymmetric braking conditions.