Acoustic vehicle alert system

Abstract

The present disclosure provides an acoustic vehicle alert system. A pedestrian alert system adapts an alert sound emitted by a vehicle according to an acoustic environment around the vehicle. Echo of an alarm sound in an enclosed space, such as a garage, may stimulate pedestrians and / or occupants of a vehicle. A sensor kit, including a radar, a camera, and / or a GPS locator, detects confined space in which reflections result in greater apparent loudness. The loudness of the emitted alarm sound is reduced, wherein the reduction in volume may be based on the size of the space.

Description

Technical Field

[0001] The present disclosure relates to an alarm system in a vehicle that emits a sound according to the acoustic environment around the vehicle. Background Art

[0002] The present invention relates generally to pedestrian warning systems and, more particularly, to adapting a warning sound emitted by a vehicle according to the acoustic environment surrounding the vehicle.

[0003] The electric motors in electric vehicles are very quiet compared to the internal combustion engines in traditional fuel-based vehicles. Additionally, as exhaust systems in traditional vehicles improve and idle stop-start systems become more common, fuel-based vehicles are also becoming quieter. Pedestrians located near a quiet vehicle may be less likely to notice a vehicle moving in their direction.

[0004] Pedestrians use the noise emitted by vehicles to help make judgments in areas where vehicles and people are in close proximity (e.g., crosswalks, parking lots, narrow streets, etc.). Audible noise can provide cues for detecting when a car is moving and judging its relative position. When audible noise is reduced, it may be more cumbersome to judge the movement and relative position of a quiet vehicle even if the vehicle is actually moving. Therefore, various governments (e.g., cities, counties, parishes, states, provinces, jurisdictions, countries, etc.) may require that vehicles emit the minimum amount of noise that pedestrians can perceive. For example, the National Highway Traffic Safety Administration is developing standards for the minimum noise levels emitted by road vehicles based in part on the standards (SAE J2889) developed by the Society of Automotive Engineers for measuring the minimum noise levels emitted by road vehicles (e.g., see NHTSA-2011-0148 and 49 C.FR §571).

[0005] According to various regulations and standards, an alarm sound with a loudness in the range of 56 to 75 decibels (measured at a fixed distance) should be generated. The alarm sound may be allowed to change frequency and / or loudness. For example, such a change may be associated with the speed of the vehicle. Different sounds (e.g., characteristic sound samples or tones) may be emitted in different directions. The alarm sound may need to be activated under certain driving conditions, which may be defined as (A) remaining stationary with the transmission selector in neutral, reverse, or drive, (B) moving backward, or (C) moving forward at a speed less than the forward cutoff speed. Above the cutoff speed, the alarm sound may become unnecessary because wind and tire noise are sufficient to make the vehicle detectable.

[0006] When warning sounds are intentionally emitted to notify pedestrians (i.e., anyone in the vicinity of the vehicle) of a moving vehicle, it may be desirable to tailor the acoustic properties of the sounds, such as loudness (i.e., audio volume), to ensure that they are perceived by the pedestrians. On the other hand, excessive loudness may be uncomfortable for pedestrians or occupants of the vehicle and should be avoided. Furthermore, noise pollution regulations may impose limits on maximum noise levels. Summary of the invention

[0007] In one aspect of the invention, a vehicle includes an acoustic transducer for projecting an alarm sound to the exterior of the vehicle. A sensor suite is configured to (1) detect a pedestrian within a predetermined proximity of the vehicle when the vehicle is in motion, and (2) determine whether the vehicle is located in a walled enclosure. A controller is configured to (A) select an audio sample to be projected for an alarm event that occurs when the pedestrian is detected within the predetermined proximity when the vehicle is in motion, and (B) determine acoustic parameters for generating the alarm sound. The acoustic parameters include: a first component, the first component including a first loudness based on a target apparent loudness that will appear at the pedestrian; and a second component, the second component including a corresponding reduction in the alarm sound when the vehicle is determined to be in the walled enclosure. The audio controller drives the acoustic transducer based on the audio sample and the acoustic parameters. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] Figure 1 Schematic diagram showing a vehicle in motion detecting a nearby pedestrian.

[0009] Figure 2 is a flow chart illustrating a method for adapting a warning sound reproduced outside a vehicle as a warning to a pedestrian.

[0010] Figure 3 is a schematic diagram showing vehicles and pedestrians within a walled enclosure such as a parking garage.

[0011] Figure 4 is a flow chart illustrating a preferred method of the present invention.

[0012] Figure 5 is a block diagram showing an embodiment of a vehicle according to the present invention.

[0013] Figure 6 is a schematic diagram showing a vehicle towing a trailer and moving past pedestrians.

[0014] Figure 7 is a flow chart illustrating an embodiment of the present invention that provides an alarm sound when a trailer is attached to a vehicle. DETAILED DESCRIPTION

[0015] In some embodiments of the present invention, an acoustic vehicle alarm system uses an external sensor suite and other resources to determine vehicle conditions, ambient loudness, and other relevant inputs to control the sound and / or tone of the vehicle's external sound generator (e.g., speaker) to ensure that pedestrians are alerted to the presence of the vehicle with minimal annoyance. The monitored conditions of the vehicle and the environment may include vehicle speed, driving gear (reverse / driving), current ambient sound level picked up by an external transducer, speed limit, GPS location, type of vehicle being driven (e.g., truck, car, and any attached trailer). Using the current vehicle location, the vehicle can determine the associated sound regulations for the current region. The external loudness will be controlled to be at least as loud as required by the regulations. In addition, the loudness is set to be at least higher than a predetermined loudness level (e.g., measured in dB and calibrated during vehicle development) of the surrounding environment (not exceeding the maximum value of the regulatory range or the level provided by the local sound regulations).

[0016] The external sensor suite may include radar, cameras, lidar, and / or other remote sensing technologies to quantify the loudness of ambient noise, the distance and orientation of pedestrians and roads, and the movement of pedestrians, vehicles, and other obstacles.

[0017] The locations of objects, people, and other beings can be mapped around the vehicle. The distances of vehicles from each other can be estimated. If a pedestrian (i.e., person or being) is moving, trajectory analysis can be performed to determine if the pedestrian is heading toward or approaching the path of a moving vehicle. Based on the proximity or trajectory, the vehicle can amplify external sounds by a calibrated gain (up to the maximum allowed volume). For example, the directionality of the alarm sound can be shifted toward where the pedestrian is by driving the speaker / sound actuator closest to the pedestrian louder, while the other speakers can remain at their normal volume.

[0018] The echo (i.e., reflection) of the alarm sound in an enclosed space (such as a garage) may irritate pedestrians and / or vehicle occupants. A sensor suite (e.g., radar, camera, or GPS locator) may be used to detect confined spaces where reflections result in greater apparent loudness, so that the emitted loudness of the alarm sound may be reduced. The reduction in volume may be based on the size of the space. The size of the reduction may be limited in order to maintain compliance with legal minimum loudness levels.

[0019] Based on how close the vehicle and / or pedestrian is to the walls and how open the enclosed space is, the loudness reduction may include a calibrated gain where the volume generated in a more confined space (walls closer together) is proportionally reduced. Additionally or alternatively, the vehicle may change the alarm sound to have higher frequency content, which may prevent the sound waves from traveling too far.

[0020] Based on the type of vehicle and whether the vehicle is towing a trailer, completely different sound types or tones (e.g., recorded sound samples) may be generated to indicate vehicle size (e.g., a truck may have a lower frequency sound, or a trailer may be indicated using a larger loudness boost above the ambient loudness).

[0021] Sound emitters can also be installed on trailers to help ensure that the trailer's presence can be heard even after a vehicle has passed by.

[0022] refer to Figure 1 , a vehicle 10 is located on a surface 11 (e.g., a road or parking area) with pedestrians 12 and 13 nearby. Sensors in the vehicle 10 may provide various monitoring zones, such as a monitoring zone 14 covering the pedestrian 12. Depending on the driving state of the vehicle 10 and the proximity / movement of the pedestrian 12 or 13, the vehicle 10 may automatically generate an alarm sound so as to be heard in a manner that makes the presence and potential movement of the vehicle 10 easily perceptible.

[0023] Figure 2 A preferred method of adapting the alarm sound to a particular situation is shown. In step 15, the ambient loudness level is measured. An external microphone or other acoustic transducer may be used to sense the ambient noise around the vehicle, which may be measured in dB. In step 16, a default loudness for the alarm sound is added to this base sound level. The default loudness provides a buffer above the ambient level to ensure that the alarm sound is not masked by existing noise. For example, the default loudness may be about 20 dB.

[0024] Additional adjustments may be made to acoustic parameters (e.g., loudness and / or content of the alarm sound) to improve usability. In step 17, various vehicle-based factors are employed. For example, a vehicle speed adjustment may include a loudness boost proportional to speed, and a trailer adjustment may include a loudness boost (e.g., +5 dB) or a reduction in the spectrum of the alarm tone when a trailer is present. In step 18, various pedestrian-based factors are employed. For example, a distance adjustment may include a loudness reduction proportional to the distance between the pedestrian and the vehicle (e.g., a 3 dB reduction at 20 feet).

[0025] In step 19, the adjusted acoustic parameter (e.g., the adjusted loudness) is compared with the adjusted parameter and clipped according to the adjusted parameter. For example, the adjusted loudness range may have a minimum value of 56 dB and a maximum value of 75 dB. If the adjusted loudness is less than 56 dB, the acoustic parameter for generating the alarm sound is increased to 56 dB, and if the adjusted loudness is greater than 75 dB, the acoustic parameter for generating the alarm sound is reduced to 75 dB. Local sound regulations may also impose an upper limit, which may also require clipping the target loudness of the alarm sound. Therefore, an acoustic parameter including the adjusted loudness is determined. The loudness is compared with an adjusted loudness range including a minimum loudness and a maximum loudness. If the determined loudness is less than the minimum loudness, it is further adjusted to be equal to the minimum loudness, and if it is greater than the maximum loudness, it is further adjusted to be equal to the maximum loudness.

[0026] Figure 3 It shows how an enclosed space creates reflections that result in a greater apparent loudness (a situation that can be addressed in the present invention by reducing the loudness of the emitted alarm sound). A vehicle 20 is located in an enclosure 21, such as a parking structure, having walls 22, 23, and 24 (in addition to the floor and ceiling) that enclose the vehicle 20 in a chamber that can limit the propagation of sound. An alarm sound 25 emitted from the vehicle 20 encounters the walls 22 and 23 to generate reflections 26 and 27, respectively, which encounter a pedestrian 28, whose presence triggers the generation of the alarm sound. Both the direct sound 25 and the reflected sounds 26 and 27 (as well as other sounds) converge on the pedestrian 28, which can result in an unpleasant experience of the alarm sound, including enhanced loudness and / or annoying echoes or interference.

[0027] according to Figure 4The method shown, the present invention can reduce the unpleasantness of the alarm sound. In step 30, a check is performed to determine whether the geographic location coordinates of the vehicle are mapped to a garage or other enclosure using a map that defines the known locations of enclosures (such as garages or parking structures). If it is determined that the vehicle is located in such a garage, corrective action can be initiated at step 35. If the geographic location is not mapped to a garage, other mechanisms can be used to determine whether the vehicle is located in a walled enclosure. Therefore, in step 31, a check is performed using a set of sensors located on the vehicle to determine whether the enclosure is detected. For example, camera images can be analyzed, or radar reflections can be monitored in an attempt to characterize the walled enclosure. If a walled enclosure is detected again, the method proceeds to step 35, otherwise another check can be performed in step 32 to determine whether an echo indicating a reflective wall is detected in the acoustic environment surrounding the vehicle. For example, an external sound (e.g., a chirp) can be generated, and the microphone signal can then be monitored to identify any immediate and strong echoes of the generated sound. If no echo is detected, it is detected that there is no walled enclosure. Therefore, it is determined at step 33 that no adjustment is required, and the method can be as shown. Figure 2 Continue as in.

[0028] When it is determined by steps 30, 31 or 32 that the vehicle is within an enclosure, the proximity of the vehicle and / or pedestrian to the walls of the enclosure may be determined in step 35. The proximity to one or more walls may be an indication of the magnitude of reflections that need to be resolved. In step 36, the target loudness of the alarm sound is reduced (e.g., as in Figure 2 The amount of reduction may be proportional to the distance of the vehicle from the wall of the enclosure or the distance of the pedestrian from the wall of the enclosure. The wall distance may be determined based on which wall is positioned to generate a strong reflection. In addition to or in lieu of reducing the loudness used to generate the alarm sound, the unpleasantness experienced by the pedestrian may be reduced by optionally raising the frequency of the alarm sound (because human hearing is less sensitive to higher frequency sounds). Thus, the frequency of the alarm sound may be raised in step 37, and the method then continues normally.

[0029] Figure 5is a block diagram showing the vehicle in more detail. A main controller 40, such as a microcontroller, includes a main logic block 41 (e.g., programming instructions) for operating the present invention. The programming also includes a pattern recognition block 42, a wall distance determination block 43, and an echo detection block 44. An audio controller 45 is coupled to the controller 41 and is connected to a speaker 46 and one or more microphones 47. The speaker 46 generates an alarm sound, and the microphone 47 can pick up external sounds, such as ambient noise levels and generated echoes. The controller 40 is coupled to a plurality of inputs 50, which include an external sensor suite 51, a GPS / positioning unit 52, and a map database 53. The sensor suite 51 may preferably include known advanced driver assistance sensors, such as image sensors, radars, lidars, ultrasonic sensors, and other sensors for detecting pedestrians within a predetermined proximity of the vehicle and for locating walls defining a wall enclosure. The controller 40 is also coupled to a multiplexed communication bus 48, which is connected to other electronic controllers in the vehicle, such as a powertrain controller, in order to monitor the driving state of the vehicle. For example, signals indicative of gear selector position and / or vehicle speed may be received via bus 48 and may be used to determine when an alarm sound is desired.

[0030] Unit 52 may include a GPS receiver or other wireless receiver capable of determining location coordinates, such as a Wi-Fi transceiver. Map database 53 identifies the locations of multiple enclosures, and logic block 41 is configured to compare the location coordinates obtained by unit 52 with map database 53 to detect when the vehicle is located in an enclosure. Alternatively or in addition, logic block 41 may utilize captured images or other sensing data from sensor suite 51 for analysis by pattern recognition unit 42 to identify walled enclosures. Logic block 41 uses wall distance block 43 to compare the relative positions of vehicles, pedestrians, and walls to estimate distances and orientations so that the effects of echoes and reflections on the perception of the alarm sound can be characterized. When the location coordinates or sensor suite pattern recognition process fails to detect a walled enclosure, logic unit 41 may use echo detection to check for reflective walls. Echo detection block 44 compares the emitted sound with the received sound, which can identify the timing and intensity of the reflections. When a walled enclosure is detected according to any of the foregoing methods, the logic block 41 can select an audio sample to be projected for an alarm event in response to detecting a pedestrian within a predetermined proximity of the vehicle when the vehicle is in motion (e.g., engaged or moving). The logic block 41 is also configured to determine acoustic parameters for generating an alarm sound, wherein the acoustic parameters include: a first component, the first component including a first loudness based on a target apparent loudness that will appear at the pedestrian; and a second component, the second component including a corresponding reduction in the alarm sound when the vehicle is determined to be in the walled enclosure. Preferably, the reduction provided by the second component may include a reduction in loudness. The reduction may include an increase in the frequency spectrum of the selected audio sample. As used herein, an audio sample includes a tone, a combination of tones, a recorded sound file, or other audio content. The reduction (i.e., an increase in frequency and / or a decrease in loudness) can be determined based on the distance between the wall of the enclosure and the vehicle or pedestrian.

[0031] Figure 6 Another situation is shown where a vehicle 50 is towing a trailer 51, thereby increasing the overall length of the unit that may interact with a pedestrian. A pedestrian 52 is within the predetermined proximity for generating an alarm sound. In addition, the pedestrian 52 may be in a position that makes it more difficult to sense the vehicle and its trailer due to the intervening parked vehicle 53. Therefore, it may be desirable to change the alarm sound to notify the pedestrian 52 of the unique situation involving the trailer.

[0032] The sensor suite 51 and logic block 41 may be configured to detect the presence of a trailer attached to the vehicle. The presence of the trailer may be indicated from another electronic module in the vehicle via a multiplexed bus. When a trailer is detected, the adjustable acoustic parameters for generating the alarm sound may include a third component that includes an enhancement of the alarm sound when an attached trailer is detected. The enhancement may include a loudness boost, or may include a unique type of sound, such as a unique tone or combination of tones for identifying the presence of a trailer.

[0033] Figure 7 A corresponding method is shown, wherein a check is performed in step 55 to determine whether a trailer is attached to the vehicle. If not, the alarm sound is not affected and the method continues according to the previous figures. When a trailer is detected, a loudness boost (e.g., +5 dB) is determined in step 56, which is applied to the alarm sound as appropriate. In step 57, a unique alarm sound identifying the presence of a trailer may be activated. For example, the frequency or spectrum of the alarm sound may be reduced.

[0034] In one aspect of the invention, the method comprises: determining a distance of a wall of the enclosure from the vehicle or from the pedestrian; wherein the increase in the frequency spectrum is determined according to the distance.

[0035] In one aspect of the invention, the step of determining whether the vehicle is located in a walled enclosure includes a wireless receiver determining location coordinates, wherein the location coordinates are compared to a map database identifying a plurality of walled enclosures at corresponding locations.

[0036] In one aspect of the invention, the step of determining whether the vehicle is located in a walled enclosure includes locating walls defining the walled enclosure using advanced driver assistance sensors.

[0037] In one aspect of the invention, the method comprises: detecting the presence of a trailer attached to the vehicle; wherein the acoustic parameter comprises a third component, the third component comprising an increase in the alarm sound when the attached trailer is detected.

[0038] In one aspect of the invention, the enhancement includes loudness enhancement or a unique sound pattern for identifying the trailer.

Claims

1. A vehicle comprising: an acoustic transducer for projecting a warning sound to the exterior of said vehicle; a sensor suite configured to (1) detect pedestrians within a predetermined proximity of the vehicle while the vehicle is in motion, and (2) determine whether the vehicle is located within a walled enclosure; a controller configured to (A) select an audio sample to be projected for an alarm event that occurs when the pedestrian is detected within the predetermined proximity when the vehicle is in the driving state, and (B) determine acoustic parameters for generating the alarm sound, wherein the acoustic parameters include: a first component including a first loudness based on a target apparent loudness that will appear at the pedestrian; and a second component including a corresponding attenuation of the alarm sound when the vehicle is determined to be in the walled enclosure; and An audio controller drives the acoustic transducer according to the audio samples and the acoustic parameters. 2 . The vehicle of claim 1 , wherein the second component comprises a loudness reduction included in the acoustic parameter.

3. The vehicle of claim 2, wherein the controller is further configured to determine a distance of a wall of the enclosure from the vehicle or from the pedestrian, and wherein the loudness reduction is determined based on the distance. 4 . The vehicle of claim 1 , wherein the second component comprises an increase in a frequency spectrum of the audio samples.

5. The vehicle of claim 4, wherein the controller is further configured to determine a distance of a wall of the enclosure from the vehicle or from the pedestrian, and wherein the increase in the frequency spectrum is determined based on the distance.

6. The vehicle of claim 1 wherein the sensor suite includes a wireless receiver that determines location coordinates, and wherein the controller compares the location coordinates to a map database that identifies a plurality of walled enclosures at corresponding locations.

7. The vehicle of claim 1 wherein the sensor suite includes advanced driver assistance sensors for locating walls defining the walled enclosure.

8. The vehicle of claim 1 , wherein the sensor suite is further configured to detect the presence of a trailer attached to the vehicle, and wherein the acoustic parameter includes a third component comprising an increase in the alarm sound when the attached trailer is detected.

9. The vehicle of claim 8, wherein the enhancement comprises loudness boost.

10. The vehicle of claim 8, wherein the enhancement includes a unique sound pattern for identifying the trailer.

11. The vehicle of claim 1 , wherein the determined acoustic parameter comprises a determined loudness, wherein the controller is further configured to compare the determined loudness to an adjusted loudness range comprising a minimum loudness and a maximum loudness, wherein if the determined loudness is less than the minimum loudness, the controller adjusts the determined loudness to be equal to the minimum loudness, and wherein if the determined loudness is greater than the maximum loudness, the controller adjusts the determined loudness to be equal to the maximum loudness.

12. A method for warning pedestrians of the presence of a moving vehicle, the method comprising the following steps: When the vehicle is in motion, detecting a pedestrian within a predetermined proximity of the vehicle; determining whether the vehicle is located in a walled enclosure; selecting an audio sample to be projected for an alert event that occurs when the pedestrian is detected within the predetermined proximity while the vehicle is in the driving state; determining acoustic parameters for generating the warning sound, wherein the acoustic parameters include: a first component including a first loudness based on a target apparent loudness to be perceived at the pedestrian; and a second component comprising a corresponding attenuation of the alarm sound when the vehicle is determined to be within the walled enclosure.

13. The method of claim 12, wherein the second component comprises a loudness reduction included in the acoustic parameter.

14. The method according to claim 13, further comprising the steps of: determining a distance of a wall of the enclosure from the vehicle or from the pedestrian; The loudness reduction is determined according to the distance.

15. The method of claim 12, wherein the second component comprises an addition to a frequency spectrum of the audio sample.

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