ACTIVE TUNED VIBRATION ABSORBER

• US 20100131114A1
• Filed: 03/05/2008
• Published: 05/27/2010
• Est. Priority Date: 03/05/2007
• Status: Active Grant

• Current Assignee: Ultra PCS Limited
• Original Assignee: Ultra Electronics Limited (Ultra Electronics Holdings PLC)
• Inventors: Stothers, Ian McGregor, Benassi, Luca
• Granted Patent: US 8,914,154 B2
• Time in Patent Office: Days
• US Class Current: 700/280
• CPC Class Codes: F16F 15/002 characterised by the control method or circuitry control of mechanical oscillations per se G05D19/00
• CPC Class Codes: F16F 7/1011 by electromagnetic means

Abstract

An active tuned vibration absorber (100) is disclosed for reducing vibrations in a structure, the vibration absorber comprising: a mount (104) for attachment to the structure; a moveable mass (106); a spring arrangement (108) connected between the mass and the mount; an actuator arrangement (110) for applying a force between the mass and the mount; a first sensor (112) for providing a first measurement indicative of a force exerted between the structure and the mount; a second sensor (114) for providing a second measurement indicative of an acceleration of the structure at or proximate to the mount; and a control system (116) for generating an actuator driving signal for driving the actuator using the first and second measurement, wherein the control system is operable to generate the actuator driving signal to cause the first measurement and second measurement to conform to a target relationship.

Claims

1. An active tuned vibration absorber for reducing vibrations in a structure, the vibration absorber comprising:

a mount for attachment to the structure;

a moveable mass;

a spring arrangement connected between the mass and the mount;

an actuator arrangement for applying a force between the mass and the mount;

a first sensor for providing a first measurement indicative of a force exerted between the structure and the mount;

a second sensor for providing a second measurement indicative of an acceleration of the structure at or proximate to the mount; and

a control system for generating an actuator driving signal for driving the actuator using the first and second measurement,

wherein the control system is operable to generate the actuator driving signal to cause the first measurement and second measurement to conform to a target relationship.

2. A vibration absorber according to claim 1, wherein the control system is operable to generate the actuator driving signal to cause a frequency domain representation of the first measurement and a frequency domain representation of the second measurement to converge to a target ratio.

3. A vibration absorber according to claim 1 or 2, wherein the control system is operable to generate an actuator drive signal to cause the mechanical impedance of the vibration absorber to converge to a target mechanical impedance substantially equivalent to the mechanical impedance of a passive tuned device.

4. A vibration absorber according to claim 1, wherein, in isolation from the actuator arrangement and control system, the moveable mass and the spring arrangement form a first resonant system having a first Q factor and, when controlled by and combined with the actuator arrangement and control system, the moveable mass and the spring arrangement form a second resonant system with a second Q factor, and wherein the second Q factor is larger than the first Q factor.

5. A vibration absorber according to claim 1, wherein the control system includes a feedforward control system.

6. A vibration absorber according to claim 5, wherein the feedforward control system is operable to process signals using a reference model that is defined in terms of characteristics of the vibration absorber, whereby the reference model does not need to take into account characteristics of the structure.

7. A vibration absorber according to claim 1, wherein the control system includes a feedback control system.

8. A vibration absorber according to claim 1, wherein the first sensor is a force sensor attached to or proximate the mount.

9. A vibration absorber according to claim 1, wherein the first sensor is an accelerometer attached to the moveable mass.

10. A vibration absorber according to claim 1, wherein the second sensor is an accelerometer attached to or proximate the mount.

11. A vibration absorber according to claim 1, further comprising a communications unit for communicating with a remote controller.

12. A vibration absorber according to claim 11, wherein the vibration absorber is operable to receive a command signal from the remote controller, and to alter the target relationship in dependence on the command signal.

13. A vibration absorber according to claim 11, wherein the vibration absorber is operable to receive a command signal from the remote controller, and to drive the actuator using the command signal.

14. A vibration absorber according to claim 11, wherein the vibration absorber is operable to determine a communications failure between the vibration absorber and the remote controller, and to adapt to a local control mode in response to the communications failure.

15. A vibration absorber according to claim 11, wherein the vibration absorber is operable to transmit at least one of the first and second measurements to the remote controller.

16. A vibration absorber according to claim 1, operable to receive a signal indicative of a characteristic frequency of vibration in the structure, and to alter the target relationship in dependence on the received signal.

17. A vibration absorber according to claim 1, operable to determine a characteristic frequency of vibration in the structure, and to alter the target relationship in dependence on the determined frequency.

18. A vibration absorber according to claim 17, wherein the vibration absorber is operable to process the first or second measurements to determine the frequency of a harmonic of a frequency of vibration, and to alter the target relationship in dependence on the determined harmonic frequency in order to counteract the vibration.

19. A vibration absorber according to claim 1, for use with a vibration source that generates vibrations having a frequency varying over time within a set of characteristic frequencies, wherein the control system further comprises:

a plurality of control subsystems taking the first and second measurements as an input, each control subsystem being tuned to a respective one of the set of characteristic frequencies; and

a processing unit for combining the output of the subsystems to generate the actuator driving signal.

20. A vibration absorber according to claim 19, wherein each control subsystem includes an adaptive filter for generating the output of the subsystem, and the control system is operable to control the adaptation of each of the adaptive filters in dependence on the degree of excitation or response of each of the subsystems.

23. A system for attenuating vibrations in a structure, comprising a plurality of active tuned vibration absorbers as defined in claim 1.

24. A system according to claim 23, further comprising a central controller, operable to receive at least one signal representative of a vibration in the structure, and to transmit a command signal to at least one of the plurality of vibration absorbers to control the or each vibration absorber to reduce the vibration.

37. A vibration absorber according to claim 1, including a control system as claimed in claim 25.

21. An active tuned vibration absorber for reducing vibrations in a structure, the vibration absorber comprising:

a mount for attachment to the structure;

a moveable mass;

a spring arrangement connected between the mass and the mount;

an actuator arrangement for applying a force between the mass and the mount;

a feedforward control system for generating an actuator driving signal for driving the actuator arrangement, the actuator driving signal being generated to cause the mechanical impedance of the vibration absorber to converge to a target mechanical impedance substantially equivalent to the mechanical impedance of a passive tuned device.

22. An active tuned vibration absorber for reducing vibrations in a structure, the vibration absorber comprising:

a mount for attachment to the structure;

a moveable mass;

a spring arrangement connected between the mass and the mount;

an actuator arrangement for applying a force between the mass and the mount;

a force sensor attached to or proximate the mount for outputting a measurement indicative of a force exerted between the structure and the mount;

a control system for generating a drive signal for the actuator arrangement using the measurement, the actuator drive signal being generated to cause the mechanical impedance of the vibration absorber to converge to a target mechanical impedance substantially equivalent to the mechanical impedance of a passive tuned device.

25. A control system for operating an active tuned vibration absorber, the vibration absorber being attachable to a structure and including an actuator arrangement, and the control system comprising:

an input stage for inputting a first signal indicative of an acceleration of the structure at or proximate to the vibration absorber and a second signal indicative of a force exerted between the structure and the vibration absorber;

an adaptive filter for outputting a control signal for driving the actuator arrangement, the adaptive filter having an input derived from the first signal;

a first processing unit for processing the first signal in accordance with a target function to generate a desired force signal representing a desired force to be applied to the vibration absorber by the structure, the target function representing a target relationship between the acceleration of the structure at or proximate to the vibration absorber and the force exerted between the structure and the vibration absorber;

a second processing unit for processing the desired force signal and the second signal to generate an error force signal representing a difference between the desired force and an estimated force applied to the vibration absorber by the structure; and

a third processing unit for adapting the adaptive filter to minimise the error force signal.

26. A control system according to claim 25, operable to generate the actuator driving signal to cause a frequency domain representation of the first measurement and a frequency domain representation of the second measurement to converge to a target ratio.

27. A control system according to claim 25, operable to generate an actuator drive signal to cause the mechanical impedance of the vibration absorber to converge to a target mechanical impedance substantially equivalent to the mechanical impedance of a passive tuned device.

28. A control system according to claim 25, wherein the adaptive filter is driven from the output of the first processing unit.

29. A control system according to claim 25, further comprising a feedback control system, the feedback control system having as input a measurement indicative of a motion of the moveable mass of the vibration absorber, and having as an output a feedback driving signal for driving the actuator arrangement.

30. A control system according to claim 25, wherein the control system is operable to process signals using a reference model that is defined in terms of characteristics of the vibration absorber, whereby the reference model does not need to take into account characteristics of the structure.

31. A control system according to claim 25, further comprising a communications unit for communicating with a remote controller.

32. A control system according to claim 31, operable to receive a command signal from the remote controller, and to alter the target relationship in dependence on the command signal.

33. A control system according to claim 31, operable to determine a communications failure between the control system and the remote controller, and to adapt to a local control mode in response to the communications failure.

34. A control system according to claim 31, operable to transmit at least one of the first and second signals to the remote controller.

35. A control system according to claim 25, operable to receive a signal indicative of a characteristic frequency of vibration in the structure, and to alter the target relationship in dependence on the received signal.

36. A control system according to claim 25, operable to determine a characteristic frequency of vibration in the structure, and to alter the target relationship in dependence on the determined frequency.

38. An active tuned vibration absorber for reducing vibrations in a structure, the structure being perturbed by a vibration source that generates vibrations having a frequency varying over time within a set of characteristic frequencies, and the vibration absorber comprising:

a mount for attachment to the structure;

a moveable mass;

a spring arrangement connected between the mass and the mount;

at least one sensor providing a measurement of a perturbation associated with the vibration source;

an actuator arrangement for applying a force between the mass and the mount; and

a control system for generating an actuator driving signal for driving the actuator using the or each measurement, comprising;

a plurality of control subsystems taking the or each measurement as an input, each control subsystem being tuned to a respective one of the set of characteristic frequencies; and

a processing unit for combining the output of the subsystems to generate the actuator driving signal.

39. A vibration absorber according to claim 38, wherein each control subsystem includes an adaptive filter for generating the output of the subsystem, and the control system is operable to control the adaptation of each of the adaptive filters in dependence on the degree of excitation or response of each of the subsystems.

40. A vibration absorber according to claim 38, wherein the or each sensor comprises a first sensor for providing a first measurement indicative of a force exerted between the structure and the mount;

and a second sensor for providing a second measurement indicative of an acceleration of the structure at or proximate to the mount, and the control system is operable to generate the actuator driving signal to cause the first measurement and second measurement to conform to a target relationship.

41. A vibration absorber according to claim 40, wherein the control system is operable to generate the actuator driving signal to cause a frequency domain representation of the first measurement and a frequency domain representation of the second measurement to converge to a target ratio.

42. A vibration absorber according to claim 40, wherein the control system is operable to generate an actuator drive signal to cause the mechanical impedance of the vibration absorber to converge to a target mechanical impedance substantially equivalent to the mechanical impedance of a passive tuned device.

43. A method of controlling an active tuned vibration absorber attached to a structure, the method comprising:

receiving a first signal indicative of an acceleration of the structure at or proximate to the vibration absorber;

receiving a second signal indicative of a force exerted between the structure and the vibration absorber;

generating an actuator driving signal using the first and second measurement for driving an actuator attached to a moveable mass,

wherein the step of generating the actuator driving signal comprises generating the actuator driving signal to cause the first measurement and second measurement to conform to a target relationship.

46. A carrier medium carrying computer readable code for controlling a computer to carry out the method of claim 43.

44. A method of reducing vibrations in a structure, comprising:

providing a mount for attachment to the structure;

providing a moveable mass;

providing a spring arrangement connected between the mass and the mount;

providing an actuator arrangement for applying a force between the mass and the mount;

providing a first sensor for providing a first measurement indicative of a force exerted between the structure and the mount;

providing a second sensor for providing a second measurement indicative of an acceleration of the structure at or proximate to the mount; and

providing a control system for generating an actuator driving signal for driving the actuator using the first and second measurement,

wherein the control system is operable to generate the actuator driving signal to cause the first measurement and second measurement to conform to a target relationship.

45. A method of controlling an active tuned vibration absorber, the vibration absorber being attachable to a structure and including an actuator arrangement, and the method comprising:

inputting a first signal indicative of an acceleration of the structure at or proximate to the vibration absorber and a second signal indicative of a force exerted between the structure and the vibration absorber;

outputting a control signal for driving the actuator arrangement, the adaptive filter having an input derived from the first signal;

processing the first signal in accordance with a target function to generate a desired force signal representing a desired force to be applied to the vibration absorber by the structure, the target function representing a target relationship between the acceleration of the structure at or proximate to the vibration absorber and the force exerted between the structure and the vibration absorber;

processing the desired force signal and the second signal to generate an error force signal representing a difference between the desired force and an estimated force applied to the vibration absorber by the structure; and

adapting the adaptive filter to minimise the error force signal.

47. A carrier medium carrying computer readable code for controlling a computer to carry out the method of claim 45.

48. (canceled)