Study On Distribution Strategy Of Redundant Actuate Fault-Tolerant Control For Four Wheels Independent Control-By-Wire Electric Vehicle Chassis

With the rapid development of modern automotive technology, the vehicle speed hasbeen continuously improved, and became the important cause of traffic accidents. Therefore,security has become one of the major topics of automotive industry development. Thevehicle will deviate the desired line, and even lose stability when braking or acceleratingalong with the faulted actuators on wheels. It is easy to cause serious traffic accident.Traditional vehicle can do nothing for this. However, the four wheels independentcontrol-by-wire electric vehicle could generate an active yaw moment used to maintainvehicle stability by allocating or compensating the driving force and braking force of wheels.It means that the yaw moment could be changed by the controlling longitudinal force oneach wheel independently, so as to the driving performance.In this paper, a four-wheels-independent control-by-wire prototype machine is builtbased on the national863plan project. According to the national natural science fund project,a complete fault-tolerant control allocation strategy is proposed, and a fault-tolerant controlframework is constructed based on the prototype machine.In the study of this subject, driving system, braking system, and steering system oftraditional vehicle are changed. Then, a prototype machine with characteristic that eachwheel longitudinal force could be controlled independently was set up. Because of thereasrerch requirement of the fault-tolerant control allocation strategy, parameters calibrationinclude motor, battery, vehicle, steering system and braking system parameters is necessary,so as to build a Carsim model. Meanwhile some tests must be done used to verify the Carsimmodel. According to the characteristic of four-wheels-independent control-by-wire prototypemachine, reasonable fault-tolerant control method and the complete fault-tolerant controlallocation strategy are proposed in this paper. And the active yaw moment could be allocated to wheels by particle swarm optimization, and minimizing the utilization rate of tires is theobject. Finally, the control model of fault-tolerant control allocation strategy is created inMatlab/Simulink, and verified by offline simulation.The results indicate that the fault-tolerant control strategy has good fault-tolerancecontrol effect in case of failure appearing in brake or drive system, and vehicle can runsafely and stably by allocating or compensating yaw moment.