Full vehicle ABS braking using the SWIFT rigid ring tyre model
In recent years, at the Delft University of Technology and TNO-Automotive and in conjunction with an industrial consortium, a pragmatic tyre model has been developed going by the name SWIFT, which is geared to the analysis of tyre oscillations and its effects on vehicle behaviour. The SWIFT tyre model has been designed to cover in-plane, out-of-plane and combined higher order dynamic tyre performance. It can be regarded as an extension of the Magic Formula pragmatic tyre model, up to a range of at least about 70 Hz. This paper describes the application of the SWIFT tyre model to full vehicle ABS braking. First, the model is used to derive the single tyre response to road undulations and brake torque step input, both being very much of relevance to ABS braking. This includes a survey of the sensitivity of the dynamic tyre parameters regarding the first, rigid belt, eigenfrequencies and the relative damping. Next, the response of a quarter vehicle to similar input is discussed with specific emphasis on the added value of the dynamic characteristics of the SWIFT model in comparison to steady state and transient tyre models. Finally, full vehicle ABS controlled braking on an even road is considered for various road friction values and vehicle speed.
Active brake control
To reference this document use:
Control Engineering Practice, 11 (2), 199-207