The Application of Active Noise Control in single General Aviation Aircraft Cabins

摘要

The application of active noise control to reduce cabin noise in single engine, general aviation aircraft is investigated through the use of the 'filtered x' least mean square algorithm. A simple acoustic feedforward method is used to generate a reference signal is tested. The system is designed to utilize one reference signal with up to two feedback signals and two audio speakers. Cabin noise and reference signals are recorded during flight in a Cessna 172 Skyhawk, a Piper Cherokee 140 and a Piper Malibu Mirage. The recorded data is used in laboratory tests to evaluate the capability of the control system to reduce the cabin noise signal with the recorded reference signal. The reference signal is found to lack coherence with the cabin noise in nost aircraft which limited noise reductions. Alternative feedforward methods are investigated and an alternative reference signal is tested in a laboratory simulation. The results with the recorded data and the modified reference signal are outlined in each case.