Model Predictive Control-Based Differential Braking System for Steer-By-Wire System Failure Response

With recent advancements in electric vehicle technology, the utilization of Steer-By-Wire (SBW) systems is increasing. However, SBW systems pose a critical issue: the complete loss of steering function in the event of a motor system failure due to the absence of mechanical linkages. This study proposes a Model Predictive Control (MPC)-based differential braking control system for safe roadside entry and stopping of a vehicle during an SBW steering motor failure. The proposed system consists of a path planner utilizing a 5th-order Bezier curve and a vehicle model-based MPC controller, where the upper-level controller calculates the required yaw moment and the lower-level controller distributes brake torque to each wheel. The effectiveness of the proposed algorithm was validated through CarSim simulations, confirming that stable vehicle control is possible even in steering system failure situations. This research is expected to enhance the fault tolerance of SBW systems and contribute to ensuring the safety of electric vehicles.