Magnetic bearing reaction wheels are currently being considered for attitude control for the Next Generation Space Telescope because of the increased control that they provide for the attenuation of transmitted vibration. This jitter will be induced through both imbalance and sensor runout. While the imbalance forces will be synchronous (1X) with the wheel speed, the sensor runout will have both synchronous and harmonic components (2X, 3X, etc.). Over the past 5 years, we have developed a technique, known as Adaptive Vibration Control (AVC), for greatly reducing synchronous vibration in rotating machinery on active magnetic bearings. This method is essentially an adaptive feedforward approach specifically tailored for the problem of rotating machinery vibration. We will apply this technique to a magnetic bearing reaction wheel (MASAREDI) at NASA Goddard Space Flight Center so as to reduce the synchronous and harmonic forces transmitted.
The AVC algorithm has been successfully applied to several different rotating machinery applications including turbomolecular pumps and a large hydrogen compressor. UVA researchers have demonstrated the reduction of transmitted synchronous forces by over 40 dB. An extensive theory for the robustness of AVC has also been developed. In addition to funding from GSFC, UVA has funding from Revolve Magnetic Bearings to develop AVC synthesis techniques.