Semi-Active Control of a Friction Joint

Dipl.Ing. Rainer Nitsche

   Zeit: Dienstag, 18. 7. 2000, 16:00
   Ort: Hörsaal V 9.31 Pfaffenwaldring 9, Universitätsbereich Stuttgart-Vaihingen

Vibration properties of most assembled mechanical systems depend on frictional damping in joints. The nonlinear transfer behavior of the friction interfaces often provide the dominant damping mechanism in a built-up structure and play an important role in the vibratory response of the structure.

With a piezoelectric stack disc, used as a washer in the joint connection, the frictional energy dissipation can be controlled. Such a "smart joint" is a semi-active device, as only the energy dissipation can be varied. A dynamic friction model, namely the Lund-Grenoble (LuGre) model is used to describe the friction between the two sliding surfaces in the joint connection. A "damping controller" for such a smart joint will be introduced. Simulation and experimental results show the significant improvement in energy dissipation in the smart joint.

Such semi-actively controlled devices are highly suitable for vibration control of large flexible structures as, due to the semi-active method, no spillover instability can be caused by the controller and moreover numerous joints are available in such structures.