This paper addresses the challenge of vehicle stability and safety during braking on split- \(\mu \) roads, where the friction coefficient varies between the left and right sides of the vehicle (e.g., snow on one side, dry asphalt on the other). We propose an advanced control strategy integrating observer-based adaptive integral sliding mode control (AISMC) with an extremum-seeking (ES) loop for reference optimization. Previous studies have explored various wheel slip control strategies, but few have effectively combined the dual objectives of minimizing stopping distance and maintaining vehicle directional stability under asymmetrical braking conditions. Our proposed approach leverages AISMC for its ability to adapt to variations in road conditions and its robustness against disturbances and model uncertainties. It also includes an observer to estimate unmeasured states, enhancing control accuracy. Concurrently, the ES loop optimizes the wheel slip reference in real-time, ensuring optimal braking performance. Validation through simulation and CarSim/Simulink co-simulations demonstrates the offered AISMC’s effectiveness in enhancing braking performance and vehicle stability on split- \(\mu \) roads. Meanwhile, several comparisons underscore the superiority and robustness of the proposed control approach.
