| The four-wheel drive(4WD) vehicle can make the best use of the ground adhesiveforce, improving the vehicle dynamic performance and passing ability. But for thefull-time4WD vehicle, one drive wheel hung in the air or slipped excessively will leadthe whole vehicle broke down for the front and rear drive axles or left and right drivewheels are connected by differential. The traction control system can control the slip ofdrive wheels by adjust its drive torque, improve the dynamic performance and handlingstability effectively.The full-time4WD vehicle is taken as the research object, by analyzing theinfluence to the vehicle dynamic performance and handling stability caused by the sliprate of drive wheels, the driving cycle of4WD vehicle with traction control systemdriving on various tough roads is studied. The main works carried in the research are asfollow:The mathematical models of the4WD vehicle are analyzed, on this basis, theparameters of the simulation environment and vehicle mathematical models are set up.By analyzing the structure and working principle of the electronic throttle system,the inter-axle electronic control limited-slip differential, inter-wheel limited-slipdifferential and hydraulic system, the scheme of the actuator for traction control systemis decided, and the responding mathematical models are established.The control methods and control objectives for traction control system are decided,then, the synthetic control strategy of traction control system based on the combinedcontrol of electronic throttle control, inter-axle torque distribution control andinter-wheel torque distribution control.According to the mathematical models, the simulations of straight acceleration for4WD vehicle with traction control system on various tough roads are carried out.The results shows that, the designed traction control system can prohibit theexcessive slip of drive wheels effectively, the dynamic performance, steering safety andhandling stability are improved greatly. |
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