Study On Traction Control Of Independent Axle Type Hybrid Four-wheel Drive Vehicle

As the newborn of a solution to global environmental degradation and energy crisis, Electric four-wheel drive hybrid vehicles is of better handling, lower fuel consumption,lower costs and better acceleration performance Compared with the traditional four-wheel drive vehicles, electric four-wheel drive vehicle is not only faced with the original problem, such as movement interference of front and rear axle, vibration and noise of diving system and cornering braking, but also the coordination of torque and speed for front and rear drive shaft become more difficult for that the front, rear axle independent drive belongs to the through the road 4WD HEV, which is no doubt a big challenge for TCS control strategy of 4WD TTR HEV( four wheel drive through the road hybrid electric vehicle).This paper took a 4WD TTR HEV as the research object, then studied torque distribution control strategy for TTR HEV driven by front and rear axle independently and traction control strategy in driving conditions, which were conducted in simulation. Specific studies include the following aspects:①Established key drivetrain components model, vehicle model and auxiliary calculation module.②Established front, rear axle drive torque coordination distribution control system based on thought hierarchical control, besides, the torque pre-allocated energy management strategy for power source, the front,rear axle drive torque distribution control strategy in axial load transfer, and the front,rear axle drive torque compensation control strategy after wheels slip occurred were further analyzed and proposed in control systems.③According to the relationship between the drive wheel drive torque, angular acceleration and wheel slip rate, the best angular acceleration αwas determined. Accelerator opening signal correction control strategies, front, rear drive axle torque distribution control and front and rear limited-slip differential torque control strategy were formulated based on α.④A separate shaft hybrid four wheel drive vehicle simulation model was built by MATLAB / Simulink software, and the influence of TCS control strategy proposed in the typical low-adhesion road on the car acceleration performance was analyzed and verified.The Simulation results indicated that: the separated axle 4WD HEV control strategy formulated in a typical low adhesion surface can effectively suppress or eliminate slip wheels and each power source torque, drive wheel torque can be adjusted based on current road adhesion conditions timely, besides the speed deviation between driving wheels touch the ground and the vehicle speed was ultimately reduced so as to ensure the acceleration of the car.