Date of Graduation

1994

Document Type

Dissertation/Thesis

Abstract

Two problems faced by the brake industries today are: (1) Longer development time because of the design approach that uses actual physical tests to evaluate and caliberat design for a specific brake and vehicle system. (2) Incapability of the ABS (Antilock Braking Systems) to optimally achieve the functional requirements of stopping distance, steerability, and stability under the wide variety of road and driving conditions that are encountered. The two problems stated above are addressed in this dissertation. A computer model is developed for brake and vehicle. Using the model analytical simulations instead of actual physical tests are performed. Simulation is an effective tool for use in design, performance evaluation and testing of antilock brakes. It provides an efficient and cost effective method of optimizing system design by allowing a way to easily vary vehicle, brake, controller and environmental parameters. Control strategies are developed and evaluated using simulation techniques. The control parameters are a function of the transient response characteristics of the brake components such as the valves, the brake line and the lower brake system (brake drum/disc and pads) and are developed in the light of such components. Vehicle yaw motion and steering angle are used as inputs to the controller in addition to the wheel information. Strategies are developed to effectively use the driver, vehicle, brake and wheel information to improve the stopping distance, steerability and stability. The controller and vehicle performance is evaluated using braking tests for both straight lines and turns. Four different type of road surfaces ranging from ice to dry asphalt are considered. Performance on non-uniform road conditions like split {dollar}\\mu,{dollar} transition, checker board and ice patch are also evaluated. The results of simulation are evaluated and compared to provide better design solutions. The performance of vehicles equipped with a four channel ABS, three channel ABS and no ABS are compared. A simplified driver model for emulating driver's steering inputs is developed. The model is based on vehicles yaw and linear deviations from the intended path.

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