ADAPTIVELY TUNED VIBRATION ABSORBER FOR REDUCTION OF AIRCRAFT CABIN NOISE

摘要

An aircraft engine is attached to the fuselage by amounting structure that has a vibration absorbing systemwhich includes first and second sensors to produce signalsindicating vibration along two orthogonal axes. A thirdsensor, such as an accelerometer, is coupled to the mountingstructure for sensing vibration of the engine. A tachometercircuit, connected to the third sensor, produces first andsecond speed signals that indicate the speeds of two rotatingspools in the engine. Four vibration absorbers are attachedto the engine mounting structure and controllers are providedto dynamically tune the resonant frequency of each vibrationabsorber in response to a unique combination of one of thetwo vibration signals and one of the two speed signals. Thusthe vibration absorbers reduce the engine spool vibrationsthat are transmitted through the mounting structure along thetwo orthogonal axes. The resonant frequency of each absorberis altered to track variation of the vibrations due to changesin engine speed.