Vehicle External Warning Sound Generation System and Method

• US 20120062391A1
• Filed: 09/15/2010
• Published: 03/15/2012
• Est. Priority Date: 09/15/2010
• Status: Active Grant

• Current Assignee: Bose Corporation
• Original Assignee: Bose Corporation
• Inventors: Pan, Davis Y.
• Granted Patent: US 8,362,921 B2
• Time in Patent Office: Days
• US Class Current: 340/901
• CPC Class Codes: B60Q 5/008 for signaling silent vehicles, e.g. for warning that a hybrid or electric vehicle is approaching
• CPC Class Codes: H03G 3/32 the control being dependent upon ambient noise level or sound level

Abstract

A vehicle external warning sound generation system and method. A transducer generates warning sounds external to the vehicle in response to an input sound signal. A sensor senses sound external to the vehicle and has an output signal that represents both sensed ambient noise and sensed warning sounds. A processing system, responsive to the sensor output signal, generates the sound signal that is provided to the transducer. The processing system includes an adaptive filter which reduces the level of the warning sounds in the sensor output signal, so that mostly ambient noise remains.

Claims

1. A vehicle external warning sound generation system, comprising:

a transducer that generates warning sounds external to the vehicle in response to an input sound signal;

a sensor that senses sound external to the vehicle and has an output signal that represents both sensed ambient noise and sensed warning sounds emitted by the vehicle; and

a processing system, responsive to the sensor output signal, that generates the input sound signal that is provided to the transducer, wherein the processing system comprises an adaptive filter which reduces the level of the vehicle'"'"'s sensed warning sounds in the sensor output signal, so that mostly ambient noise remains in the sensor output signal.

2. The system of claim 1 wherein the adaptive filter determines the transfer function from the transducers generating the warning sounds to the sensor output signal.

3. The system of claim 2 wherein the processing system models the warning sound signal within the sensor output signal and removes the modeled warning sound signal, to leave an ambient noise signal.

4. The system of claim 3 wherein one or more properties of the generated warning sounds are related to the ambient noise signal.

5. The system of claim 4 wherein the properties comprise the volume, such that the generated warning sounds are audible over the ambient noise.

6. The system of claim 4 wherein the properties comprise the frequency, such that the frequency of the generated warning sound is related to the ambient noise.

7. The system of claim 6 wherein the generated warning sounds are divided into a plurality of frequency bands, and the gain in each band is adjusted based on the ambient noise level in that band.

8. The system of claim 6 wherein the processing system further comprises an equalizer that alters the volume of one or more frequency bands of the generated warning sound signal.

9. The system of claim 1 wherein the generated warning sounds have a particular frequency or frequency range, and the system further comprises a filter for the sensor output signal that removes contributions to the sensor output signal from sensed frequencies that are outside the particular auditory masking frequency or frequency range of the warning sounds.

10. The system of claim 1 wherein the processing system is further responsive to the vehicle speed such that one or more properties of the warning sounds is related to the vehicle speed.

11. The system of claim 10 wherein the properties include the volume and pitch of the warning sounds.

12. The system of claim 1 further comprising a second sensor that senses the roughness of the surface on which the vehicle is traveling, wherein the processing system is further responsive to the second sensor such that the volume of the generated warning sounds is indirectly related to the sensed roughness.

13. The system of claim 1 wherein the sensor comprises a microphone.

14. The system of claim 1 wherein the transducer comprises a loudspeaker.

15. The system of claim 1 wherein the processing system comprises a digital signal processor.

16. The system of claim 1 wherein the processing system further comprises a variable gain element and a volume control with dynamic equalization.

17. A vehicle external warning sound generation system, comprising:

a transducer that generates warning sounds external to the vehicle in response to an input sound signal;

a first sensor that senses sound external to the vehicle and has an output signal that represents both sensed ambient noise and sensed warning sounds emitted by the vehicle;

a second sensor that senses the roughness of the surface on which the vehicle is traveling;

a third sensor that senses the speed of the vehicle;

a processing system, responsive to the first, second and third sensors, that generates the input sound signal that is provided to the transducer, wherein the processing system comprises an adaptive filter which reduces the level of the vehicle'"'"'s sensed warning sounds in the sensor output signal so that mostly ambient noise remains in the sensor output signal, wherein the adaptive filter determines the transfer function from the transducer generating the warning sounds to the sensor output signal, wherein the processing system models the warning sound signal within the sensor output signal and removes the modeled warning sound signal to leave an ambient noise signal;

wherein the processing system is further responsive to the second sensor such that the volume of the warning sounds is indirectly related to the sensed surface roughness, and the processing system is still further responsive to the third sensor such that one or both of the volume and pitch of the generated warning sounds is related to the vehicle speed; and

wherein one or both of the volume and pitch of the generated warning sounds are also related to the ambient noise such that the generated warning sounds are audible over the ambient noise and the frequency-dependent gain of the generated warning sound is related to the ambient noise.

18. A method of modulating vehicle external warning sounds using a system that comprises a transducer that generates warning sounds external to the vehicle, and a sensor that senses sound external to the vehicle and has an output signal that represents both sensed ambient noise and sensed warning sounds emitted by the vehicle, the method comprising:

providing a processing system;

providing the sensor output signal to the processing system; and

using the processing system to generate the sound signal that is provided to the transducer to cause the transducer to generate the warning sounds, wherein the processing system comprises an adaptive filter which reduces the level of the vehicle'"'"'s sensed warning sounds in the sensor output signal, so that mostly ambient noise remains in the sensor output signal.

19. The method of claim 18 wherein the adaptive filter determines the transfer function from the transducer generating the warning sounds to the sensor output signal, wherein the processing system models the warning sound signal within the sensor output signal and removes the modeled warning sound signal to leave an ambient noise signal, and wherein one or more properties of the warning sounds are related to the ambient noise signal.

20. The method of claim 19 wherein the properties of the warning sounds comprise the volume, such that the warning sounds are audible over the ambient noise, and the frequency, such that the frequency of the warning sound is related to the ambient noise.

21. The method of claim 20 wherein the generated warning sounds are divided into a plurality of frequency bands, and the gain in each band is adjusted based on the ambient noise level in that band.

22. The method of claim 18 wherein the processing system is further responsive to the vehicle speed such that at least one of the volume and pitch of the generated warning sounds is related to the vehicle speed.

23. The method of claim 18 further comprising providing a second sensor that senses the roughness of the surface on which the vehicle is traveling, wherein the processing system is further responsive to the second sensor such that the volume of the generated warning sounds is indirectly related to the sensed roughness.

24. A vehicle external warning sound generation system, comprising:

a transducer that generates warning sounds external to the vehicle in response to an input sound signal;

a sensor that senses the roughness of the surface on which the vehicle is traveling;

a processing system, responsive to the sensor, that generates the input sound signal that is provided to the transducer;

wherein the processing system is responsive to the sensor such that the volume of the warning sounds is indirectly related to the sensed surface roughness.