Helicopter active noise control system
First Claim
1. An active noise control system for a helicopter for effectively nullifying high frequency vibrations emanating from the main transmission gearbox thereof to significantly reduce interior noise levels of the helicopter, comprising:
- modified transmission beam means including mounting hardpoints for interfacing the main transmission gearbox in combination with the airframe of the helicopter, said modified transmission beam means being mechanically stiffened with respect to at least one of the high frequency vibrations emanating from the main transmission gearbox wherein said modified transmission beam means function as a rigid body with respect to said at least one high frequency vibration;
actuator means mounted in combination with said modified transmission beam means adjacent said transmission gearbox and airframe interface for generating a plurality of single dimensional counterforces having a frequency, magnitude, and phase to effectively nullify said at least one high frequency vibration at said transmission gearbox and airframe interface; and
means operative with respect to said at least one high frequency vibration to detect magnitudes and frequencies of single dimensional components thereof at said transmission gearbox and airframe interface and to provide command signals to control operation of said actuator means to generate said single dimensional counterforces having said frequency, magnitude, and phase to effectively nullify said at least one high frequency vibration at said transmission gearbox and airframe interface wherein the interior noise levels of the helicopter are significantly reduced.
1 Assignment
0 Petitions
Accused Products
Abstract
An active noise control (ANC) system for a helicopter that is operative to effectively nullify one or more high frequency vibrations emanating from the main transmission gearbox thereof at the gearbox/airframe interface, thereby significantly reducing the interior noise levels of the helicopter, that is design optimized to minimize the number of actuators required, and that is design optimized to minimize contamination forces arising from operation of the system actuators. The ANC system includes modified transmission beams that are mechanically stiffened to function as rigid bodies with respect to the one or more of the high frequency vibrations, a plurality of actuators disposed in combination with the modified transmission beams, a plurality of sensors disposed in combination with the modified transmission beams in a collinear, spaced apart functional correlation with respective actuators, and controllers interconnecting individual actuators with respective functionally correlated sensors.
92 Citations
15 Claims
-
1. An active noise control system for a helicopter for effectively nullifying high frequency vibrations emanating from the main transmission gearbox thereof to significantly reduce interior noise levels of the helicopter, comprising:
-
modified transmission beam means including mounting hardpoints for interfacing the main transmission gearbox in combination with the airframe of the helicopter, said modified transmission beam means being mechanically stiffened with respect to at least one of the high frequency vibrations emanating from the main transmission gearbox wherein said modified transmission beam means function as a rigid body with respect to said at least one high frequency vibration; actuator means mounted in combination with said modified transmission beam means adjacent said transmission gearbox and airframe interface for generating a plurality of single dimensional counterforces having a frequency, magnitude, and phase to effectively nullify said at least one high frequency vibration at said transmission gearbox and airframe interface; and means operative with respect to said at least one high frequency vibration to detect magnitudes and frequencies of single dimensional components thereof at said transmission gearbox and airframe interface and to provide command signals to control operation of said actuator means to generate said single dimensional counterforces having said frequency, magnitude, and phase to effectively nullify said at least one high frequency vibration at said transmission gearbox and airframe interface wherein the interior noise levels of the helicopter are significantly reduced. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15)
-
Specification