Wheel-corner brake failures can significantly deteriorate vehicle stability and safety, since unbalanced braking forces may introduce an undesired yaw moment. This work investigates a fault-tolerant control strategy for Active Wheel-Corner Systems, exploiting Four-Wheel Independent Steering (4WIS) to mitigate such effects and preserve vehicle stability when brake actuator malfunctions occur. Unlike many existing approaches, the proposed framework does not require explicit fault detection or quantification as a prerequisite for corrective action, eliminating potential delays and uncertainties associated with fault-diagnosis schemes. A reference model for yaw rate and sideslip angle, incorporating combined longitudinal and lateral dynamics, is proposed, and a Weighted Pseudo-Inverse Control Allocation (WPCA) scheme is employed to distribute corrective actions among the four steering angles according to each tire’s capability, compensating for yaw moment imbalances caused by degraded braking performance. The overall control framework is evaluated using a high-fidelity vehicle model implemented through VI-CarRealTime, with control algorithms and fault scenarios integrated via MATLAB/Simulink, providing a flexible and realistic platform for systematic analysis. The strategy is tested in cornering maneuvers with fault injection representing the worst-case scenario of a complete failure of the outer-front wheel brake. Results demonstrate that 4WIS can effectively recover the desired vehicle response, reducing deviations in yaw rate and sideslip compared to a baseline vehicle without reconfiguration. The study highlights the potential of steering redundancy as a complementary solution to braking and torque-vectoring systems for improving fault tolerance in future Active Wheel-Corner systems.
Sonnino et al. (Wed,) studied this question.