THE IMPLICATIONS OF SYNCHRONIZED CANCELLATION FOR VIBRATION

The success of the synchronous adaptive waveform cancellation technique for removing high levels of low-frequency noise leads naturally to the adoption of the technique for vibration cancellation. Many engine-related noises begin as vibrations within the engine body, and only become significant as noise following their transmission through the engine mounts into the supporting structure. The vibrational modes operating at each engine mounting point can be resolved into three orthogonal directions -- and so cancelled by three orthogonal actuators. The paper briefly discusses the disadvantages of conventional actuator configurations and describes an alternative approach in "free-fall".