A piezo-based bearing for the active structural acoustic control of rotating machinery

This paper presents an active bearing for reducing the radiated structure borne noise of rotating machinery. This modular bearing uses piezostacks to generate secondary forces in the vibration transmission path of the controlled structure. The bearing is tested on an experimental test bed comprising a rotating shaft, which is mounted in a frame. Noise is radiated by a plate that is attached to the frame. To evaluate different control approaches, a simplified model of the set-up was made. Based on the simulation results, a combination of feedback and repetitive control is implemented, using a force and acceleration measurement. This way, a noise reduction of more than 10 dB is achieved at the most important resonance frequencies of the system below 1 kHz.