Advanced fault-tolerant strategies and quantification for 4WID-4WIS vehicles with actuator faults

The four-wheel independent drive and four-wheel independent steering (4WID-4WIS) vehicles offer increased redundancy in fault-tolerant control schemes, enhancing heterogeneous fault-tolerant capabilities. This paper thoroughly analyzes single subsystem faults and lateral-longitudinal coupling faults. A novel method using boundary feature points is proposed to calculate vehicle attainable force domains, significantly reducing computational time without compromising accuracy. Additionally, a unified fault-tolerant control strategy based on control allocation is designed to address all types of complete actuator failures. Matlab/Simulink and Carsim co-simulation results demonstrate vehicle performance under multiple fault types, establishing the mapping between attainable force domains and fault-tolerant control performance using linear regression. Singular value decomposition is utilized to characterize fault tolerance, leading to a unified fault tolerance index and a quantification framework for 256 fault scenarios. This research provides a comprehensive understanding of fault tolerance boundaries, offering critical references for improving driving safety and maneuverability, especially in complex and emergency scenarios.