Active adaptive selective control system

• US 5,715,320 A
• Filed: 08/21/1995
• Issued: 02/03/1998
• Est. Priority Date: 08/21/1995
• Status: Expired due to Term

• Current Assignee: Digisonix Incorporated
• Original Assignee: Digisonix Incorporated
• Inventors: Brokish, Charles W., Allie, Mark C., Eriksson, Larry J.
• Primary Examiner(s): Kuntz, Curtis
• Assistant Examiner(s): CHIN, VIVIAN C
• Application Number:
  US08/517,464
• Time in Patent Office: 897 Days
• Field of Search: 381/71, 381/94, 381/71.1, 381/71.8, 381/71.11, 381/71.12, 381/94.1, 381/94.2, 381/94.9, 364/724.19, 333/166
• US Class Current: 381/71.12
• CPC Class Codes: G10K 11/17817 between the output signals and the error signals, i.e. secondary path
• CPC Class Codes: G10K 11/17833 by using a self-diagnostic function or a malfunction prevention function, e.g. detecting abnormal output levels
• CPC Class Codes: G10K 11/17854 the filter being an adaptive filter
• CPC Class Codes: G10K 11/17879 using both a reference signal and an error signal
• CPC Class Codes: G10K 11/17881 the reference signal being an acoustic signal, e.g. recorded with a microphone
• CPC Class Codes: G10K 2210/112 Ducts
• CPC Class Codes: G10K 2210/3012 Algorithms
• CPC Class Codes: G10K 2210/3017 Copy, i.e. whereby an estimated transfer function in one functional block is copied to another block
• CPC Class Codes: G10K 2210/3028 Filtering, e.g. Kalman filters or special analogue or digital filters
• CPC Class Codes: G10K 2210/3029 Fuzzy logic; Genetic algorithms
• CPC Class Codes: G10K 2210/3037 Monitoring various blocks in the flow chart
• CPC Class Codes: G10K 2210/3049 Random noise used, e.g. in model identification

Abstract

An active adaptive control system introduces a control signal from an output transducer (14) to combine with the system input signal (6) and yield a system output signal (8). An error transducer (16) senses the system output signal and provides an error signal (44). An adaptive filter model (40) has a model input from a reference signal (42) correlated to the system input signal, and an output outputting a correction signal (46) to the output transducer to introduce the control signal. Performance of the model is selectively controlled to control the signal sent to the output transducer. Various monitoring and control methods are provided, including spectral leak signal monitoring and control, correction signal monitoring and control, frequency responsive spectral transfer function processing of the leak signal and/or the correction signal, reference signal processing, and fuzzy logic control.

Claims

1. An active adaptive control method comprising introducing a control signal from an output transducer to combine with a system input signal and yield a system output signal, sensing said system output signal with an error transducer providing an error signal, providing an adaptive filter model having a model input from a reference signal correlated to said system input signal, and an output outputting a correction signal to said output transducer to introduce said control signal, spectrally controlling performance of said model to maximize the signal sent to said output transducer at frequencies of interest, providing a spectral leak signal degrading performance of said model, and controlling said leak signal according to frequency.

2. The method according to claim 1 comprising monitoring said correction signal and controlling said leak signal in response thereto.

3. The method according to claim 2 comprising filtering said correction signal to provide said leak signal.

4. The method according to claim 3 comprising spectrally processing said correction signal by supplying said correction signal through a frequency responsive spectral transfer function.

5. The method according to claim 4 comprising modeling the transfer function between said output transducer and said error transducer with a second model, and wherein said spectral transfer function is a function of said second model.

6. The method according to claim 4 comprising supplying said correction signal from said model output through said frequency responsive spectral transfer function to an error input of said model.

7. The method according to claim 2 wherein said model output outputs said correction signal to said output transducer to introduce said control signal according to a weight update signal, and comprising combining said reference signal and said error signal to provide said weight update signal, and controlling said leak signal by controlling said weight update signal in response to said correction signal.

8. The method according to claim 1 comprising providing a copy of said model, said copy having an output supplied to said error input of said model, said copy having a filter input receiving a spectrally proccessed input signal from a spectral transfer function, said copy having a control input controlling convergence gain of said copy and receiving a spectral control signal.

9. The method according to claim 8 wherein said spectral control signal is responsive to said correction signal.

10. The method according to claim 9 comprising providing a second spectral transfer function, and supplying said correction signal through said second spectral transfer function to said control input of said copy to provide said spectral control signal.

11. The method according to claim 10 wherein said first and second spectral transfer functions are the same.

12. The method according to claim 10 comprising modeling the transfer function between said output transducer and said error transducer with a second model, and wherein each of said first and second spectral transfer functions is a function of said second transfer function.

13. The method according to claim 10 wherein said first and second spectral transfer functions are different.

14. The method according to claim 1 comprising spectrally processing said leak signal such that

at frequencies where maximum power from said output transducer reaches said error transducer, the correction signal supplied to said output transducer is maximized, and

at frequencies where minimum power from said output transducer reaches said error transducer, the correction signal supplied to said output transducer is minimized.

15. The method according to claim 14 comprising modeling the transfer function between said output transducer and said error transducer with a second model, and spectrally processing said leak signal as a function of said second model.

16. The method according to claim 15 wherein said function of said second model is the inverse of said second model.

17. The method according to claim 16 wherein said first model is controlled by an update signal from said inverse of said second model such that

at frequencies where maximum power from said output transducer reaches said error transducer, said second model has a maximum transfer characteristic and said inverse of said second model has a minimum transfer characteristic minimizing leakage of said update signal, to enable maximum output of said first model, and

at frequencies where minimum power from said output transducer reaches said error transducer, said second model has a minimum transfer characteristic and said inverse of said second model has a maximum transfer characteristic maximizing leakage of said update signal, to minimize the output of said first model.

18. The method according to claim 1 comprising filtering said reference signal to provide said leak signal.

19. The method according to claim 18 comprising spectrally processing said reference signal by supplying said reference signal through a frequency responsive spectral transfer function.

20. The method according to claim 19 comprising modeling the transfer function between said output transducer and said error transducer with a second model, and wherein said spectral transfer function is a function of said second model.

21. The method according to claim 18 comprising monitoring said correction signal and controlling said leak signal in response thereto.

22. The method according to claim 1 comprising spectrally processing said leak signal by supplying said leak signal through a frequency responsive spectral transfer function.

23. The method according to claim 22 wherein said leak signal is provided by said correction signal, and comprising supplying said correction signal through said frequency responsive spectral transfer function.

24. The method according to claim 23 comprising supplying said correction signal from said model output through said frequency responsive spectral transfer function to said error input of said model.

25. The method according to claim 24 comprising providing a copy of said model, and supplying said correction signal from said model output through said frequency responsive spectral transfer function and through said copy to said error input of said model.

26. The method according to claim 22 comprising providing a copy of said model, and supplying said leak signal through said frequency responsive spectral transfer function and through said copy to said error input of said model.

27. The method according to claim 26 wherein said copy has a filter input receiving the output of said frequency responsive spectral transfer function, said copy has a control input controlling convergence gain of said copy, and comprising providing a second frequency responsive spectral transfer function, and supplying said correction signal from said output of said model through said second frequency responsive spectral transfer function to said control input of said copy.

28. The method according to claim 26 comprising supplying a random noise signal to the input of said spectral transfer function.

29. The method according to claim 26 comprising supplying said correction signal from said output of said model to the input of said spectral transfer function.

30. The method according to claim 1 comprising spectrally controlling performance of said model in response to said correction signal.

31. The method according to claim 30 wherein said model outputs said correction signal to said output transducer to introduce said control signal according to a weight update signal, and comprising combining said reference signal and said error signal to provide said weight update signal, monitoring and spectrally sensing said correction signal and providing selective leakage of said weight update signal in response thereto to control performance of said model according to frequency, to optimize performance of said model in frequency ranges of interest.

32. The method according to claim 30 comprising providing a copy of said model and supplying the output of said copy to said error input of said model and monitoring and spectrally sensing said correction signal and providing an input to said copy in response thereto to control performance of said model according to frequency, to optimize performance of said model in frequency ranges of interest.

33. The method according to claim 1 comprising frequency weighting said leak signal to optimize performance of said model in frequency ranges of interest.

34. The method according to claim 33 comprising frequency weighting said leak signal by spectrally processing said correction signal through a frequency responsive spectral transfer function.

35. The method according to claim 33 comprising frequency weighting said leak signal by spectrally processing said correction signal through a frequency responsive spectral transfer function and through a copy of said model.

36. The method according to claim 33 comprising frequency weighting said leak signal by spectrally processing a random noise signal through a frequency responsive spectral transfer function and through a copy of said model.

37. The method according to claim 33 comprising frequency weighting said leak signal by spectrally processing a random noise signal through a first frequency responsive spectral transfer function and through a copy of said model, and spectrally processing said correction signal through a second frequency responsive spectral transfer function and through said copy of said model.

38. The method according to claim 33 comprising frequency weighting said leak signal by spectrally processing said correction signal through a first frequency responsive spectral transfer function and through a copy of said model, and spectrally processing said correction signal through a second frequency responsive spectral transfer function and through said copy of said model.

39. The method according to claim 1 comprising spectrally controlling performance of said model in response to said reference signal.

40. The method according to claim 39 wherein said model outputs said correction signal to said output transducer to introduce said control signal according to a weight update signal, and comprising combining said reference signal and said error signal to provide said weight update signal, monitoring and spectrally sensing said reference signal and providing selective leakage of said weight update signal in response thereto to control performance of said model according to frequency, to optimize performance of said model in frequency ranges of interest.

41. An active adaptive control system comprising an output transducer introducing a control signal to combine with a system input signal and yield a system output signal, an error transducer sensing said system output signal and providing an error signal, an adaptive filter model having a model input from a reference signal correlated to said system input signal, and an output outputting a correction signal to said output transducer to introduce said control signal, a spectral controller spectrally controlling performance of said model to maximize the signal sent to said output transducer at frequencies of interest, said spectral controller providing a spectral leak signal degrading performance of said model and controlling said leak signal according to frequency.

42. An active adaptive control method comprising introducing a control signal from an output transducer to combine with a system input signal and yield a system output signal, sensing said system output signal with an error transducer providing an error signal, providing an adaptive filter model having a model input from a reference signal correlated to said system input signal, and a model output outputting a correction signal to said output transducer to introduce said control signal according to a weight update signal, adaptively varying said weight update signal by providing a spectral leak signal degrading performance of said model and controlling said leak signal according to frequency.