Ph.D. Proposal Presentation by Jeff W. Badertscher
Wednesday, June 15, 2005

(Dr. Kenneth A. Cunefare, Chair)

"Investigation into the Suppression of Automotive Brake Squeal using High-Frequency Dither Signals"


One of automotive braking system's primary difficulties since their inception has been brake squeal. Research into predicting and eliminating brake squeal has been conducted since the 1930s; but despite the extensive research in this area, the exact mechanism responsible for and a universal way of eliminating squeal have yet to be determined. The proposed method of eliminating squeal of interest in this research is dither control. Dither is defined to be a high frequency (relative to system's low order resonances) disturbance used to modify a system's characteristics.

In previous research, numerical and experimental techniques were used to gain understanding of how dither signals suppress brake squeal. By applying a normal dither signal through one of the brake pads, Cunefare & Graf suppressed and prevented brake squeal on an experimental brake dynamometer. Using a single-degree-of-freedom (SDOF) friction oscillator and continuous plate model, the impact of normal and tangential dither signals on the system's dynamic stability has been investigated.

The proposed research will use experimental and numerical techniques to shed light on the origin of brake squeal and the impact of one control technique, namely dither control. The experimental investigation will consist of investigating the robustness of normal and tangential dither control on an experimental brake dynamometer and mapping the system's modal characteristics with and without dither control. The numerical research will extend Michaux's work to include two multiple degree-of-freedom models for the brake pad. These new models will allow for new combined friction and modal effects to be investigated.