Avoiding creep groan: Investigation on active suppression of stick-slip limit cycle vibrations in an automotive disk brake via piezoceramic actuators

摘要

Creep groan in automotive disk brakes is a prevalent low frequency vibration phenomenon. It may occur when a car accelerates slowly from standstill with slightly operating brake as it might be the case for cars with automatic transmission or at slopes. The origin of creep groan is friction-induced vibrations from the pad-disk contact in the brake resulting in stick-slip limit cycles. These stick-slip limit cycles may excite comprehensive structural vibrations in the car leading to structure-borne sound and passengers' discomfort. The investigations in the present paper focus on the origin of this phenomenon - by considering set-ups concentrating on the pad-disk contact - and the possibility of suppressing the stick-slip limit cycle vibrations by excitation with piezoceramic actuators. Therefore, two test set-ups are investigated. The simpler one just uses disk, brake pads and caliper from an industrial brake, while carrier and suspension are replaced. The other one considers a complete brake including serial carrier and suspension. Low frequency stick-slip limit cycles could be observed in both test set-ups and a corresponding nonlinear model including the bristle friction law is developed for both systems.