Virtual location noise signal estimation for engine order cancellation

Patent metadata

Field	Value
Publication number	US-11183166-B1
Application number	US-202017091449-A
Country	US
Kind code	B1
Filing date	Nov 6, 2020
Priority date	Nov 6, 2020
Publication date	Nov 23, 2021
Grant date	Nov 23, 2021

Abstract

A system and method for accurately estimating engine noise at a virtual microphone location, such as an occupant's ear position, in an acoustic space in order to enhance performance of an Engine Order Cancellation (EOC) system is provided. A set of weights and transfer functions that are dependent on various vehicle parameters, such as frequency, load, and speed, may be employed to estimate noise at a position where there are no physical microphones present. The accurate estimation of engine noise at virtual location, such as an occupant's ear position, may be achieved using a frequency dependent weighted sum of filtered and unfiltered error signals measured at microphones mounted at various locations inside an acoustic space, such as a vehicle cabin, which may not be located near virtual location.

First claim

What is claimed is:

1. A method of estimating noise at a virtual microphone location for an engine order cancellation (EOC) system, the method comprising:
receiving a plurality of estimated noise signals indicative of noise at a location of each of a plurality of error microphones, wherein each estimated noise signal is based at least in part on an error signal from each of the plurality of error microphones;
filtering each estimated noise signal using a virtual path filter modeled according to a transfer function between each corresponding error microphone location and the virtual microphone location to generate a plurality of filtered estimated noise signals;
adaptively weighting each filtered estimated noise signal using a weight that varies based on current vehicle conditions to generate a plurality of weighted filtered estimated noise signals; and
generating an estimated virtual microphone noise signal indicative of noise at the virtual microphone location based on a superposition of at least the plurality of weighted filtered estimated noise signals.

2. The method of claim 1 , wherein each virtual path filter is a finite impulse response filter.

3. The method of claim 1 , wherein each weight is selected from a plurality of weights stored in a lookup table and derived for application to individual filtered estimated noise signals based on the current vehicle conditions.

4. The method of claim 1 , wherein the virtual microphone location corresponds to an occupant's ear position.

5. The method of claim 1 , further comprising:
receiving the estimated virtual microphone noise signal at an adaptive filter controller; and
adjusting an adaptive transfer characteristic of an adaptive filter based in part on the estimated virtual microphone noise signal.

6. The method of claim 1 , wherein the current vehicle conditions include a frequency of engine order noise such that each weight varies based at least on the frequency.

7. The method of claim 6 , wherein the current vehicle conditions further include at least one of engine load and vehicle speed such that each weight is further selected based on at least one of the engine load and the vehicle speed.

8. The method of claim 1 , wherein each of the plurality of estimated noise signals are split into two signals paths including a first signal path and a second signal path, wherein an output of the second signal path includes the plurality of weighted filtered estimated noise signals, the method further comprising:
adaptively weighting each estimated noise signal in the first signal path using a weight selected based on the current vehicle conditions to generate a plurality of weighted estimated noise signals.

9. The method of claim 8 , wherein generating the estimated virtual microphone noise signal indicative of noise at the virtual microphone location based on the superposition of at least the plurality of weighted filtered estimated noise signals comprises:
generating the estimated virtual microphone noise signal indicative of noise at the virtual microphone location based on a superposition of the plurality of weighted estimated noise signals from the first signal path and the plurality of weighted filtered estimated noise signals from the second signal path.

10. An engine order cancellation (EOC) system comprising:
at least one adaptive filter configured to generate an anti-noise signal based on an adaptive transfer characteristic and a reference signal received from a reference signal generator, the adaptive transfer characteristic of the at least one adaptive filter characterized by a set of filter coefficients;
an adaptive filter controller, including a processor and memory, programmed to adapt the set of filter coefficients based on the reference signal and an estimated virtual microphone noise signal indicative of noise at a virtual microphone location; and
a virtual location noise estimator in communication with at least the adaptive filter controller, the virtual location noise estimator including a processor and memory programmed to:
receive a plurality of estimated noise signals indicative of noise at a location of each of a plurality of error microphones, wherein each estimated noise signal is based at least in part on an error signal from each of the plurality of error microphones;
filter each estimated noise signal using a virtual path filter modeled according to a transfer function between each corresponding error microphone location and the virtual microphone location to generate a plurality of filtered estimated noise signals;
adaptively weight each filtered estimated noise signal using a weight selected and varied based on current vehicle conditions to generate a plurality of weighted filtered estimated noise signals; and
generate the estimated virtual microphone noise signal indicative of noise at the virtual microphone location based on a superposition of at least the plurality of weighted filtered estimated noise signals.

11. The system of claim 10 , wherein each weight is selected from a plurality of weights derived for application to individual filtered estimated noise signals based on the current vehicle conditions.

12. The system of claim 10 , wherein the current vehicle conditions include a frequency of engine order noise and each weight varies based at least on the frequency.

13. The system of claim 10 , wherein each virtual path filter is a finite impulse response filter.

14. The system of claim 10 , wherein each of the plurality of estimated noise signals are split into two signals paths including a first signal path and a second signal path, wherein an output of the second signal path includes the plurality of weighted filtered estimated noise signals, the virtual location noise estimator further programmed to:
adaptively weight each estimated noise signal in the first signal path using a weight selected based on the current vehicle conditions to generate a plurality of weighted estimated noise signals.

15. The system of claim 14 , wherein the virtual location noise estimator is programmed to generate the estimated virtual microphone noise signal indicative of noise at the virtual microphone location based on the superposition of the plurality of weighted estimated noise signals from the first signal path and the plurality of weighted filtered estimated noise signals from the second signal path.

16. The system of claim 15 , wherein the virtual microphone location is a fixed point in space, distanced from the plurality of error microphones, corresponding to an occupant's ear position.

17. A method of estimating noise at a virtual microphone location for an engine order cancellation (EOC) system, the method comprising:
receiving a plurality of estimated noise signals indicative of noise at a location of each of a plurality of error microphones, wherein each estimated noise signal is based at least in part on an error signal from each of the plurality of error microphones;
transmitting each estimated noise signal along a first signal path and a second signal path;
applying a weight to each estimated noise signal in the first signal path, each weight being individually selected and varied based on current vehicle conditions, to generate a plurality of weighted estimated noise signals;
filtering each estimated noise signal in the second signal path using a virtual path filter modeled according to a transfer function between each corresponding error microphone location and the virtual microphone location to generate a plurality of filtered estimated noise signals;
applying a weight to each

Assignees

• Harman Int Ind

Inventors

• Basu Sattwik
• Tackett Jeffrey Charles
• Trumpy David
• May James
• Tousignant Todd Edward

Classifications

• G10K2210/1282

  Automobiles · CPC title

• G10K11/17879

  using both a reference signal and an error signal · CPC title

• G10K11/17854 Primary

  the filter being an adaptive filter · CPC title

• G10K2210/3028

  Filtering, e.g. Kalman filters or special analogue or digital filters · CPC title

• G10K2210/3026

  Feedback · CPC title