Research on a Stability Control Strategy for Braking Failure in Distributed-Drive Electric Vehicles

Distributed-drive electric vehicles (DDEVs) improve braking stability through independent four-wheel braking torque control, yet their complex multi-brake systems are prone to braking faults that cause loss of longitudinal and yaw stability. This study investigates DDEV braking performance under normal and faulty conditions and proposes a three-module braking stability control strategy consisting of demand torque calculation, fault constraint reconstruction, and fault-tolerant control. The fault constraint reconstruction module establishes braking capacity boundaries based on real-time fault and vehicle state data and constrains four-wheel braking torque via target projection. A composite fault-tolerant control scheme combining active front steering (AFS) and braking torque distribution is developed to suppress stability degradation. The AFS adopts a sliding-mode algorithm for accurate front wheel steering regulation, while a quadratic programming algorithm optimizes four-wheel braking torque allocation. Hardware-in-the-loop simulations are conducted for straight line and double lane change braking under single wheel regenerative, mechanical, and complete braking failure conditions. The results reveal that the proposed strategy limits peak yaw rates to 1.1 deg/s, 2.8 deg/s, and 3.5 deg/s in faulty regenerative, mechanical, and complete straight line braking, respectively, and achieves excellent yaw rate and trajectory tracking during faulty double lane change braking. This work provides an effective solution for DDEV braking stability optimization and fault-tolerant control.