IMPROVEMENTS TO VEHICLE TRACTION CONTROL SYSTEM USING ROAD DATA

Consumer demand and regulatory pressure have forced automakers to develop features designed to increase passenger car safety regardless of road surface or weather condition. In response, the intelligent tire, proposed in the APOLLO report, is introduced and the parameters useful for traction control system development are identified. Traction control system models are introduced and discussed. A simple vehicle model based on the quarter-car is presented, incorporating a traction control system and tire friction model. This model utilizes the LuGre friction model to relate tractive force to slip ratio and road surface friction level. A sliding-mode control strategy is chosen to model traction control behavior. Three case studies are conducted on two simulated road surfaces to show the interaction between estimated friction level in the sliding-mode control strategy and the tire friction model. To simulate the intelligent tire, where the road surface friction level is directly measured, the estimated friction level and actual road surface friction are set equal. Simulation results demonstrate that an accurate estimation of road surface friction level, which can be directly measured using the intelligent tire, enable the traction control model to control slip ratio to the desired level while not intervening unnecessarily across the two surfaces studied.