Modeling, simulation, and sensitivity analysis of a road vehicle during emergency braking

For the purpose of studying the response of the system to severe braking conditions, three dynamic models of a road vehicle were developed. After comparing the results of the simulations with the experimental data, the most reliable model was selected for the investigation of the response of the vehicle to variation of its parameters. A primary consideration in the development of the model was its relative simplicity so as to facilitate the implementation of its algorithms into vehicle systems controllers. The model was validated by subjecting it to different inputs and road conditions and comparison with existing results. Motion analysis of the modeled vehicle was performed and time histories of the lateral acceleration, yaw rate, and yaw angle were compared with experimental results for dynamic response of a typical passenger car to a steering maneuver. Results showed that the behavior of the simulated model were in good agreement with the experimental data, confirming its reliability. For design improvements of conventional braking system, sensitivity analysis of vehicle response to simultaneous changes in vehicle/environment characteristics was performed. Various Anti-lock Brake systems were implemented in the mathematical model and their effectiveness under different road/vehicle conditions were characterized.; The possibility of actively increasing the normal ground reaction forces was investigated through implementation of an inertia element embedded in chassis and free to accelerate in the fore/aft or vertical direction at a controlled rate. Result indicated that motion of the inertia element in the fore/aft direction improved the stopping distance slightly for road vehicles equipped with fixed ratio brake systems.; The mathematical model developed is sufficiently complete and can be an effective tool in the controller design of vehicle's subsystems such as active suspension, and steering control. The sensitivity analysis performed, closes the gap between the design improvements of conventional braking systems and the state-of-the-art ABS by characterizing the dynamic behavior of the model for changes in vehicle design attributes.