A Simulation Model for Vehicle Braking Systems Fitted with ABS 2002-01-0559

Most vehicles built today are fitted with anti-lock braking systems (ABS). Accurate simulation modeling of these vehicles during braking as well as combined braking and steering maneuvers thus requires the effects of the ABS to be included. Simplified, lump parameter models are not adequate for detailed, 3-dimensional vehicle simulations that include wheel spin dynamics. This is especially true for simulating complex crash avoidance maneuvers. This paper describes a new ABS model included in the HVE simulation environment. It is a general purpose model and is available for use by any HVE-compatible vehicle simulation model. The basic operational and control characteristics for a typical ABS system are first reviewed. Then, the specific ABS model and its options as implemented in the HVE simulation environment and employed by the SIMON vehicle simulation model are described. To validate the model, pressure cycles produced by the model are compared with stated engineering requirements. In addition, pressure vs. time histories for two ABS simulations on surfaces with different frictional characteristics are compared with experimental data. Finally, the gross effects of ABS on two simulated maneuvers (straight-line braking and ISO 3888 lane-change maneuver) are presented.