Hierarchical Safety-Critical Control Method for DDEV During Handling Limit: A Strategy via Safety Region Reconstruction and Extension

Benefited from the advantage of four-wheel independent driving, Distributed Driving Electric Vehicle (DDEV) can precisely generate direct yaw moment (DYC) to influence lateral motion. In coordination with Active Front Steering (AFS), this allows for decoupled control under normal driving condition. However, DYC is fundamentally generated through the longitudinal forces of the tires, so its impact on dynamic stability under handling limit cannot be ignored. Particularly, the intervention of DYC changes the vehicle’s safety boundary, a factor seldom addressed in existing research. Extension literatures use the safety boundaries of traditional Centralized Driving Vehicle (CDV) to design stability controller for DDEV, resulting in conservative or aggressive performance. To this end, we propose a hierarchical safety-critical controller for DDEV during handling limit. A feedback control law based on high-order polynomials is constructed, and the closed-loop stability boundary is expanded using the Sum of Square Programming (SOSP) algorithm. Additionally, DYC is included in the stability margin assessment, and a safety envelope boundary suitable for DDEV is reconstructed. This safety boundary is used as a state constraint to design a safety-critical controller based on ODCBF. Simulation and experiments show that the proposed algorithm can widen the stable yaw rate boundary by 15% under high-speed continuous steering condition, enhancing the vehicle’s maneuverability while ensuring safety. Note to Practitioners—DDEV use in-wheel motors as actuators, providing more control freedom and superior handling performance, making it a core research area for many automotive manufacturers. Stability is a crucial factor affecting vehicle safety. Almost all vehicles should be equipped with active safety systems, such as Bosch’s Electronic Stability Program (ESP) and GM’s Electronic Stability Controller (ESC). However, most of these systems are developed for CDV, while DDEV have an additional control input DYC. This means that traditional ESP control strategies may be too conservative for DDEV, preventing the full utilization of the capabilities. Therefore, this paper reconstructs the stability region for DDEV and expands the stability boundary through closed-loop DYC control. This technology fills the gap in the stability margin determination of DDEV and has promising applications in the active safety systems.