Adaptive resonator vibration control system

• US 5,621,656 A
• Filed: 10/11/1994
• Issued: 04/15/1997
• Est. Priority Date: 04/15/1992
• Status: Expired due to Fees

• Current Assignee: NCT Group, Inc.
• Original Assignee: Noise Cancellation Technologies, Inc. (NCT Group, Inc.)
• Inventors: Langley, Andrew J.
• Primary Examiner(s): Voeltz, Emanuel T.
• Assistant Examiner(s): Vo, Hien
• Application Number:
  US08/318,630
• Time in Patent Office: 917 Days
• Field of Search: 364/484, 364/495, 364/508, 364/551.01, 364/571.01, 364/572, 364/724.01, 364/574, 364/578, 364/431.08, 364/148, 73/611, 73/648, 73/649, 73/662
• US Class Current: 700/280
• CPC Class Codes: F16F 7/1005 characterised by active control of the mass
• CPC Class Codes: G10K 2210/129 Vibration, e.g. instead of, or in addition to, acoustic noise
• CPC Class Codes: G10K 2210/3028 Filtering, e.g. Kalman filters or special analogue or digital filters
• CPC Class Codes: G10K 2210/3045 Multiple acoustic inputs, single acoustic output
• CPC Class Codes: G10K 2210/32271 Active resonators
• CPC Class Codes: G10K 2210/501 Acceleration, e.g. for accelerometers

Abstract

This invention relates to control systems for the control of noise and vibration. Resonators with adjustable properties are used in conjunction with an electronic control system to change the noise or vibration in a structure. The invention relates particularly to the control of quasi-periodic noise or vibration comprising one or more harmonics by using one or more adaptive resonators.

Claims

1. A noise or vibration control system for controlling noise or vibration from one or more sources comprising:

one or more self adaptive resonator means, attached to one or more points on a structure, whose resonance frequencies are adjustable by control signals;

sensor means on said resonator means, the structure, or both said resonator means and said structure that are used to determine tuning of the resonator means;

one or more sensor means on the source of vibration, the structure, or both said source of vibration and said structure that can be used to derive frequencies of various components of the vibration;

a control system that has as inputs output signal from the sensor means, and as outputs control signals to change the resonance frequencies of the resonator means,

wherein the control system incorporates a control algorithm to tune the resonator means close to selected frequencies in the noise or vibration, and to keep them tuned as those frequencies drift or as other factors affecting the resonator means'"'"' performances change.

2. A system as in claim 1, including a combination of tracking filters, harmonic filters, or Fourier transformation in order to discriminate against unwanted components in the sensor means inputs to the control system.

3. A system as in claim 1, wherein the control system uses models of the resonator means in the control algorithm.

4. A system as in claim 3 wherein the control system updates and refines the models of the resonator means as it operates.

5. A system as in claim 1, wherein the control system aims either to minimize or to maximize quantities that are proportional to a moduli of input impedances of the resonator means.

6. A system as in claim 5 wherein the control system uses a gradient descent algorithm.

7. A system as in claim 3 wherein the control system uses measurement-based one-step algorithm.

8. A system as in claim 3, wherein additional sensor means that monitor other parameters affecting performance of the resonator means form inputs to the control system.

9. A noise or vibration control system for controlling noise or vibration from one or more sources comprising

one or more self adaptive resonator, attached to one or more points on a structure, whose resonance frequencies are adjustable by control signals;

a plurality of sensors on said resonator, said structure, or both, that are used to determine tuning of the resonator; and

a control system having as inputs outputs from said sensors, and as outputs control signals to change the resonance frequencies of the resonators wherein the control system incorporates an algorithm to tune the resonators close to selected frequencies in the noise or vibration, and to keep them tuned as those frequencies drift,

wherein said control system aims either to minimize or to maximize quantities that are proportional to a modulus of input impedances of the resonator means.

10. A system as in claim 9 wherein the control system uses models of the resonator means in the control algorithm.

11. A system as in claim 10 wherein the control system updates and refines the models of the resonator means as it operates.

12. A system as in claim 9 wherein the control system uses a gradient descent algorithm.

13. A system as in claim 10 wherein additional sensor means that monitor other parameters affecting the performances of the resonator means form inputs to the control system.

14. A noise or vibration control system for controlling noise or vibration from one or more sources comprising,

one or more adaptive resonator means attached to one or more points on a structure, whose resonance frequencies can be adjusted by control signals,

sensor means on the said resonator means and/or the structure that are used to determine the tuning of the resonator means, and

a control system that has as inputs, the sensors, and as outputs, control signals to change the resonance frequencies of the resonator means wherein the control system incorporates an algorithm to tune the resonator means close to selected frequencies in the noise or vibration, and to keep them tuned as those frequencies drift (or as other factors affecting the resonator means'"'"' performances change). This control system is combined with an active-control system (plus its sensors and actuators) whose performance is designed to complement the resonator means in reducing noise or vibration in the structure.