| Summary: | 碩士 === 輔仁大學 === 電子工程學系 === 93 === Good braking performance should have two conditions: shorter stopping distance and good steering performance. The objective of an anti-lock braking system is to maximize the tire tractive force between road surface and wheel by controlling the braking piston pressure and to shorten the braking distance while maintaining adequate vehicle controllable and stability. In this thesis, for the unknown road conditions we design the road estimator that employ the dynamic friction model (LuGre Model) which described tire/road frict action behavior. We use the road estimator to identify the road conditions during the vehicle-stopping period. For the controller design, this thesis adopts sliding mode control theorem because of its well-know roboust for system uncertainty. In addition, in order to reduce the chattering problem caused by the sliding mode controller. The controller is modified to have a boundary layer, whose control signal varies smoothly inside the boundary layer. Our main control strategy is using the Anti-Lock Braking system’s controller to control the vehicle’s slip ratios track the variant optimal slip ratios, which obtained by road estimator. Simulation results will show the validity and effectiveness of the proposed methods.
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