Research on Regenerative Braking and Fault-Tolerant Control Strategy of Pure Electric Commercial Vehicles Based on Brake-By-Wire Control

With global warming, the depletion of fossil energy, and the growth of the automobile industry, countries are now placing great emphasis on the R&D of new energy vehicles. At present, the progress of electric vehicles is accelerating, but there exist drawbacks, including short driving ranges and long charging times. The selection of electric vehicle configuration and regenerative braking (RB) strategy are currently the best ways to solve the shortcomings of electric vehicles. A good RB configuration and strategy can improve energy recovery efficiency and economy. The configuration of a wheel hub motor plus a wire control brake can improve energy recovery efficiency. However, the current technology of electronic mechanical braking systems is not mature enough, resulting in a high failure rate. Since the vehicle braking fault tolerance potential of this configuration is strong, a fault-tolerant control strategy can be devised to increase security. We established a vehicle dynamics model with single-wheel failure and double-wheel failure, analyzed the vehicle stability under different failure conditions, and selected yaw rate, heading angle, sideways distance, and braking distance as evaluation indicators of vehicle stability. The effects of various failure conditions on the vehicle were examined with joint simulation. According to different failure conditions, we designed fault-tolerant control strategies for mild, moderate, and severe brake failure conditions, with the control targets being yaw rate and center of mass sideslip angle. Under severe failure conditions, we designed a front wheel steering angle sliding film controller to coordinate control with the fault-tolerant control strategy to enhance the vehicle braking stability. A large number of experimental results prove that our proposed solution has good reliability.