Hybrid active-passive noise and vibration control system for aircraft

An active system for reducing interior noise and vibration of an aircraft, said aircraft having a fuselage which includes a fuselage wall at least partially defining a passenger compartment, said fuselage and said passenger compartment being exposed to noise and vibration caused by at least one disturbance source interconnected to said fuselage wall by a support structure, said system comprising in combination:

• (a) reference signal generating means for deriving a reference signal representative of a disturbance frequency of said at least one disturbance source,
• (b) a passive resonant device attached to at least one selected from a group consisting of:
• ii) said support structure, and
• iii) said fuselage,
• (c) an active acoustic producer for generating cancelling acoustic noise within said passenger compartment attached to at least one selected from the group consisting of:
• i) said support structure, and
• ii) said fuselage, said active acoustic producer being attached at a separate and distinct point from a point at which said passive resonant device is attached
• (d) error sensor means for providing a residual error signal indicative of a residual acoustic noise within said passenger compartment, and
• (e) controller means for processing said reference signal and said residual error signal and providing a cancelling signal to drive said active acoustic producer.

A system for reducing interior noise and vibration of an aircraft, said aircraft having a fuselage which includes a fuselage wall at least partially defining a passenger compartment, said fuselage and said passenger compartment being exposed to noise and vibration caused by first and second power plants interconnected to said fuselage wall by first and second support structures, said system comprising in combination:

• (a) reference signal generating means for deriving a first reference signal representative of a first disturbance frequency of said first power plant and a second reference signal representative of a second disturbance frequency of said second power plant,
• (b) a plurality of passive tuned vibration absorbers attached to at least one selected from a group consisting of:
• i) said support structure, and
• ii) said fuselage,
• (c) a plurality of active tuned vibration absorbers spaced apart from said plurality of passive tuned vibration absorbers for generating cancelling acoustic noise within said passenger compartment which are attached to at least one selected from a group consisting of:
• i) said support structure, and
• ii) said fuselage,
• (d) error sensor means for providing a plurality of residual error signals indicative of a residual acoustic noise at a plurality of locations within said passenger compartment, and
• (e) controller means for processing said first and said second reference signals and said plurality of residual error signals and providing a plurality of cancelling signals to drive said plurality of active tuned absorbers.