Sensitivity of Steering Wheel Nibble to Suspension Parameters, Tire Dynamics, and Brake Judder

This paper presents a unified framework for addressing NVH related issues attributed to tire uniformity and Brake rotor DTV. While the focus is on the perceptible manifestation of such vibration (nibble), the presentation goes to the root-cause of nibble and how various suspension/tire/brake components contribute to the generation/amplification of such vibration. While the tire/brake excitation mechanisms have different origins, they cause the same (nibble) symptom to the driver. Results are presented for three types of vehicle suspensions, along with procedures that were developed specifically for this study and some of the understanding that was gained.. Also presented is an efficient data reduction scheme that makes it easy to visualize 3D motions of suspension components and investigate their dynamics. Amongst the “take-aways” from this study are 1) an understanding of how tire/brake excitation causes nibble, 2) an overview of the various parameters influencing nibble sensitivity, and 3) How this information can be used to alter the NVH attributes of a given vehicle.