Warning system and vehicle with acoustic device of the same attached

Abstract

To effectively prevent entry of a vehicle into a traffic regulated region.SOLUTION: This warning system comprises: an acoustic device provided with a speaker array in which a prescribed number of speaker arrangement parts each having a prescribed number of speakers arranged in a horizontal direction are disposed in a vertical direction; and an acoustic control device that drives each speaker to emit a sound. In the speaker array, a speaker in one speaker arrangement part and a speaker in the other speaker arrangement part adjacent thereto are arranged so as to be shifted in position by a prescribed distance in the vertical direction. The acoustic control device drives each speaker in the speaker array so that a sound level can be lowered from the center to the end in the speaker horizontal direction in the speaker arrangement part, and the depression angle of the sound emitted from the speaker array is set on the basis of a prescribed change condition.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present invention relates to a warning system and a vehicle equipped with an acoustic device in said warning system. [Background technology]

[0002] On roads such as expressways, toll roads, and motorways on which vehicles travel, traffic control areas are set up by restricting lanes in response to construction work, accident processing, etc. However, accidents can occur when a traveling vehicle enters a traffic control area.

[0003] Therefore, a technology is known in which dangerous vehicles that pose a risk of entering a maintenance work site on a vehicle road are detected based on the behavior of vehicles traveling on the vehicle road, and an alarm is issued using a rotating light and an alarm sound when a dangerous vehicle is detected (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 6448171 Summary of the Invention [Problem to be solved by the invention]

[0005] However, since the technology described in Patent Document 1 issues an alarm to workers in a traffic controlled area, it is difficult to prevent vehicles from entering the traffic controlled area.

[0006] The present invention has been made in view of the above circumstances, and an object of the present invention is to effectively prevent vehicles from entering a traffic controlled area. [Means for solving the problem]

[0007] One aspect of the present invention that solves the above-mentioned problems is a warning system that includes an acoustic device having a speaker array in which a predetermined number of speakers are arranged in a vertical direction, and an acoustic control device that drives each of the speakers to radiate sound, and a warning system in which a speaker in one speaker array section in the speaker array and a speaker in another speaker array section adjacent to the first speaker array section are arranged such that their positions in the vertical direction are shifted by a predetermined distance from each other, and the acoustic control device drives each of the speakers in the speaker array so that the sound level decreases from the center to the edge in the horizontal direction of the speakers in the speaker array sections, and sets the elevation and depression angles of the sound radiated from the speaker array based on predetermined change conditions.

[0008] One aspect of the present invention is the warning system described above, wherein the acoustic control device may set the directivity of the elevation and depression angles of the sound emitted from the speaker array based on the difference in air temperature in the vertical direction above the road surface. In this specification, "setting the directivity" includes "changing" as well as "maintaining" or "fixing" the directivity.

[0009] (3) One aspect of the present invention is a warning system as described above, further comprising a sensor for measuring air temperature at each of a plurality of measurement points at different heights relative to the road surface, and the acoustic control device may set the directivity of the sound radiated from the speaker array in terms of elevation and depression angles based on the difference in air temperatures measured at the plurality of measurement points.

[0010] One aspect of the present invention is a warning system as described above, wherein the acoustic control device may set the directivity of the elevation and depression angles of the sound emitted from the speaker array based on the gradient conditions of the road on which the acoustic device is installed.

[0011] One aspect of the present invention is a warning system described in any one of the above, wherein the acoustic control device may set directivity in elevation and depression angles of sound by signal processing of acoustic signals supplied to speakers in the speaker array.

[0012] One aspect of the present invention is the warning system according to any one of the above, wherein the speaker is a horn speaker.

[0013] One aspect of the present invention is a warning system as described in any one of the above, further comprising a vehicle detection device that detects vehicles traveling on a road, and the acoustic control device may drive the speaker in response to the vehicle detection device detecting a vehicle.

[0014] One aspect of the present invention is the warning system described above, wherein the vehicle detection device may be configured not to detect vehicles in the opposite lane of a road on which vehicle detection is to be performed.

[0015] One aspect of the present invention is the warning system described above, wherein the vehicle detection device detects a vehicle based on reflection of irradiated light, radio waves, or ultrasound, and determines whether to enable or disable vehicle detection based on the return time of the irradiated light, radio waves, or ultrasound. One aspect of the present invention is a vehicle equipped with an acoustic device in any one of the warning systems described above. One aspect of the present invention is a vehicle equipped with an audio device in the audio system described above. Effect of the Invention

[0016] As described above, according to the present invention, it is possible to effectively prevent vehicles from entering a traffic controlled area. [Brief description of the drawings]

[0017] [Figure 1] 1 is a diagram illustrating an example of the overall configuration of a warning system according to an embodiment of the present invention. [Diagram 2]4A and 4B are diagrams illustrating an example of installation of a temperature sensor in the present embodiment. [Diagram 3] FIG. 1 is a diagram showing an example of an installation form of a warning system according to an embodiment of the present invention. [Figure 4] 2A to 2C are diagrams showing examples of speaker arrangements in the audio device according to the present embodiment. [Diagram 5] 1 is a diagram showing an example of a case in which the audio device according to the present embodiment is mounted on a work vehicle. [Figure 6] FIG. 2 is a diagram illustrating an example of the configuration of a sound output processing unit in the present embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0018] The warning system of this embodiment is configured to emit a warning sound to a driver of a vehicle in order to prevent the vehicle traveling on a highway from entering a traffic control area that has been set up for construction work, accident processing, or the like on the road on which the vehicle is traveling. The road on which the warning system of this embodiment is used is not particularly limited as long as it is an environment on which vehicles travel and traffic control areas are established, such as expressways, toll roads, motorways, general roads, etc. In the following description, a case in which the warning system of this embodiment is used on an expressway will be taken as an example.

[0019] 1 shows an example of the overall configuration of a warning system according to the present embodiment. The warning system according to the present embodiment includes a vehicle detection device 100, an audio control device 200, an audio device 300, and a temperature sensor 400.

[0020] The vehicle detection device 100 detects vehicles traveling within a predetermined range upstream of a traffic control area on a highway. The method by which the vehicle detection device 100 detects vehicles is not particularly limited, but as an example, a method such as Lidar (Light Detection and Ranging) that measures the shape of the surrounding environment based on the return time of irradiated laser light reflected by an object and returning to a sensor can be adopted. The vehicle detection device 100 may also employ a method of detecting an object based on the return time of radio waves or ultrasonic waves instead of laser light.

[0021] The vehicle detection device 100 may be able to change the distance (measured distance) to a detectable vehicle. For example, even in a situation where the installation location of the vehicle detection device 100 on a highway is restricted, the vehicle traveling within a desired detection range can be appropriately detected by changing the measured distance. As an example, the vehicle detection device 100 can change the measured distance within a range of 5 cm to 40 m.

[0022] Furthermore, the vehicle detection device 100 transmits information indicating the detection result for the vehicle (detection information) to the sound control device 200 via communication. The communication between the vehicle detection device 100 and the sound control device 200 may be wireless or wired. In the following description, a case where the communication between the vehicle detection device 100 and the sound control device 200 is wireless will be taken as an example.

[0023] The acoustic control device 200 emits a warning sound from each of a plurality of speakers forming a speaker array included in the acoustic device 300. The acoustic signal as the warning sound is not particularly limited, and may be, for example, a sound having a predetermined waveform such as a sine wave, a wideband or narrowband noise signal, or a voice uttering a predetermined warning message. Furthermore, the acoustic control device 200 controls the speaker array so as to change the elevation and depression angles of the sounds radiated from the entire speaker array.

[0024] The acoustic control device 200 includes a communication unit 201 and a warning sound processing unit 202. The communication unit 201 wirelessly communicates with the vehicle detection device 100. The warning sound processing unit 202 causes the acoustic device 300 to emit a warning sound. In other words, the warning sound processing unit 202 drives each of a plurality of speakers provided in the acoustic device 300, thereby causing the acoustic device 300 to emit a warning sound.

[0025] The acoustic control device 200 may be configured to include a computer configured to realize functions such as a communication unit 201 and a warning sound processing unit 202 by executing a program. The computer may be configured to include a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), and a storage device such as an HDD (Hard Disk Drive) or an SSD (Solid State Drive).

[0026] The acoustic device 300 includes a speaker array in which a plurality of speakers are arranged, and emits a warning sound to vehicles traveling in a traffic control area on a highway or upstream of the traffic control area. In this embodiment, the acoustic control device 200 drives the acoustic device 300 at a timing corresponding to reception of vehicle detection information indicating that the vehicle detection device 100 has detected a vehicle in the same lane as a lane where a traffic restriction is being implemented (a restricted lane). By performing such driving, the acoustic device 300 can emit a warning sound when a vehicle enters the restricted lane of a section (a restricted road section) where a traffic restriction area is provided, and can not emit a warning sound when no vehicle is entering the restricted lane of the restricted road section. This can prevent the warning sound from being emitted when it is not necessary, thereby reducing the impact of noise on surrounding houses and the like.

[0027] In the warning system of this embodiment, the vehicle detection device 100 may be omitted. In the case where the vehicle detection device 100 is omitted, the acoustic control device 200 may constantly emit a warning sound from the acoustic device 300. In addition, when vehicles are stopped and stuck due to a traffic jam or the like, the emission of the warning sound may be stopped. The emission of the warning sound may be performed by control or manually.

[0028] The temperature sensor 400 is installed at a predetermined location corresponding to the traffic control area, and measures the temperatures at a plurality of measurement points at different heights relative to the road. In this embodiment, the temperature sensor 400 is configured to measure the temperatures at two measurement points. Note that the temperature sensor 400 may be omitted when the temperature is measured manually.

[0029] 2 shows an example of the installation of the temperature sensor 400. The temperature sensor 400 in the figure includes two sensors, a sensor 401-1 and a sensor 401-2. The sensor 401-1 is installed at a predetermined height close to the road RD, and the sensor 401-2 is installed at a predetermined height farther from the road RD than the sensor 401-2. The sensors 401-1 and 401-2 are each connected to the sound control device 200 wirelessly or by wire so as to be able to communicate with the sound control device 200, and transmit the detected air temperature to the sound control device 200. The sound control device 200 sets the elevation and depression angles of the sound radiated from the entire speaker array based on the difference between the air temperatures transmitted from the sensors 401-1 and 401-2.

[0030] FIG. 3 shows an example of an installation state of the warning system of this embodiment on a highway. The upstream restricted area (rear warning zone) in the figure will be described later. In this figure, one of the uphill and downhill roads on an expressway is shown. The road in this figure has two lanes LN-3 and LN-4 between a shoulder LN-1 and a central reservation LN-2. In this case, an example is shown in which a traffic control section is set up on the shoulder LN-1 and the lane LN-3.

[0031] In the figure, the area within lane LN-3 surrounded by direction indicator sign DP and cone CN is a traffic control area. The section of the expressway that includes the traffic control area is a restricted road section. The traffic control area is divided into the approach area, upstream safety zone, work zone, and downstream safety zone, proceeding from the upstream side of the road. The lead-in section is a section where lane LN-3 is designed to gradually merge into lane LN-4 by the placement of directional indicator signs DP.

[0032] The upstream safety zone is the first section to be set up after the approach ends and the entire lane LN-3 becomes a traffic control zone; it is a section of a certain distance secured upstream of the work zone for safety. A work section is a section within a traffic restriction area where the intended work (construction, accident clearance, etc.) is carried out. The downstream safety belt is a section of a certain distance secured for safety downstream of the work area. The section from the upstream safety belt to the downstream safety belt is divided into lanes LN-3 and LN-4 by placing cones CN.

[0033] In the figure, an example is shown in which the vehicle detection device 100 is disposed at an entrance in a traffic control area. In the case of the figure, the vehicle detection device 100 is provided so as to detect a general vehicle VHG entering a section corresponding to the entrance in lane LN-3 of the traffic control section. In this specification, the term "general vehicles" refers to all vehicles other than work vehicles and other vehicles that are planning to enter the traffic controlled area and that are traveling on the roads without any particular relationship to the establishment of the traffic controlled area or work, etc. within that area.

[0034] In the figure, the vehicle detection device 100 is set to detect general vehicles that are about to enter an entrance into a traffic-controlled area, but this is merely a schematic example. Specifically, the vehicle detection device 100 may be set to detect general vehicles traveling upstream a specified distance from the traffic-controlled area by setting the installation position and detection distance of the vehicle detection device 100.

[0035] Also, in the figure, an example is shown in which the sound control device 200 and the sound device 300 are installed in a loaded state on a work vehicle VHW. The work vehicle VHW is parked facing backward on the lane LN-3 in the upstream safety belt in the traffic control area. In this state, the sound device 300 is provided on the loading platform of the work vehicle VHW so as to emit sound toward the rear. In this embodiment, the sound device 300 emits sound toward general vehicles traveling on the lane LN-3 upstream of the traffic control area. Note that the directivity and emission direction of the sound device 300 may be set so that sound is emitted toward general vehicles traveling on the lane LN-4 in addition to the lane LN-3.

[0036] In addition, the figure shows an example in which the temperature sensor 400 is installed in a traffic controlled area on lane LN-3.

[0037] In this manner, in an alarm system in which a vehicle detection device 100, an audio control device 200, and an audio device 300 are installed, the vehicle detection device 100 detects a general vehicle VHG entering lane LN-3 in the traffic controlled section, and transmits the vehicle detection information to the audio control device 200.

[0038] The acoustic control device 200 drives the acoustic device 300 at a timing corresponding to the reception of the vehicle detection information. The speaker array of the acoustic device 300 is directed toward the rear of the road, and the acoustic device 300 emits a warning sound toward the rear of the road.

[0039] The warning sound emitted from the acoustic device 300 reaches the general vehicle VHG, and the driver of the general vehicle VHG hears the warning sound. The driver is informed by the warning sound that a traffic control zone is set up ahead, and can change lanes from lane LN-3 to lane LN-4 as shown in the figure. In this way, the warning system can prevent accidents caused by general vehicles traveling on the expressway entering the traffic control zone.

[0040] In order to further draw attention to the traffic regulations, a warning system may be installed in the upstream restricted section upstream of the restricted road section, as shown as the tail warning zone in the figure. The work vehicle VHW installed in the tail warning zone may be, for example, a tail warning vehicle equipped with a signboard to notify drivers that lanes are merging.

[0041] An example of the arrangement of speakers in the audio device 300 will be described with reference to FIG. In the figure, a speaker arrangement R (R#1 to R#4) in which ten speakers 302 are arranged in the horizontal direction is formed on a mounting plate 301. In the example of the figure, four speaker arrangements R#1 to R#4 are arranged in the vertical direction. In this way, in the acoustic device 300 of the figure, a speaker array is formed with 10 speakers in the horizontal direction and 4 speakers in the vertical direction, totaling 40 speakers.

[0042] The number of speakers arranged in the horizontal and vertical directions to form the speaker array is not particularly limited, and can be determined according to the required volume, directivity, the size of the vehicle in which the acoustic device 300 will be loaded, the size of the speaker 302 to be adopted, etc.

[0043] Channel numbers are assigned to speaker rows in the vertical direction of the speaker array in response to driving of the speaker 302 by the acoustic control device 200. Specifically, the figure shows an example in which ch1 to ch10 are assigned to the speaker rows from left to right when looking at the speaker array from the front.

[0044] In this way, it is possible to obtain increased volume and narrow directivity by forming a speaker array in which a plurality of speakers 302 are arranged. In this case, by arranging a greater number of speakers 302 in the horizontal direction than in the vertical direction, it is possible to obtain narrow directivity in the horizontal plane parallel to the road surface.

[0045] Further, the type of speaker 302 is not particularly limited, but in this embodiment, a horn speaker may be used. The horn speaker has, for example, a rectangular opening (mouth), is provided with a magnetic circuit connected to a horn in the depth direction, and radiates sound when a signal is applied to an input terminal. Since the horn speaker can obtain a large volume, it is possible to increase the reach of the sound radiated from the speaker array. Specifically, in a test of the acoustic device 300 of this embodiment, a reach of about 200m to 300m was obtained.

[0046] In addition, in the speaker array of this embodiment, the volume of each speaker 302 is set so that the volume emitted from the speaker 302 of the channel located at the center in the horizontal direction is maximum, and for the remaining channels, the volume decreases in stages from the center to the outside. In other words, in the speaker array, the volume emitted from the speaker 302 is optimally weighted according to the distance from the center in the horizontal direction based on a theory such as Dolph-Chebyshev weighting coefficients.

[0047] As a specific example, the speaker array in this case is divided horizontally into ch1 to ch5 on the left side and ch6 to ch10 on the right side by a center line C along the vertical direction. In this case, the weighting of ch5 and ch6 is set to 1 at the maximum, and the weighting values ​​less than 1 are gradually decreased from ch4 to ch1, and the weighting values ​​less than 1 are also set for ch7 to ch10, the same as ch4 to ch1. Speaker 302 emits warning sounds at volumes corresponding to the respective weightings.

[0048] In this way, the loudspeaker array is designed to emit warning sounds with a volume weighted in the horizontal direction, thereby suppressing the side lobes emitted from the loudspeaker array. By suppressing the side lobes, it is possible to control the narrow directivity of the loudspeaker array and suppress noise in the surrounding environment.

[0049] Furthermore, in the speaker array of the acoustic device 300 of this embodiment, the speakers 302 are arranged in a staggered vertical (left-right) position. Specifically, the speakers 302 of the speaker arrangement section R#1 and the speakers 302 of the speaker arrangement section R#2 arranged adjacently below are arranged so as to be shifted from each other by about half the width in the horizontal direction. The speakers 302 of the speaker arrangement section R#3 are arranged at the same position in the horizontal direction as the speaker arrangement section R#1, and the speakers 302 of the speaker arrangement section R#4 are arranged at the same position in the horizontal direction as the speaker arrangement section R#2.

[0050] In a speaker array, the speakers are arranged in a dense line, so that the distance between adjacent speakers is almost equal to the size of the speaker aperture. In this case, if the distance between adjacent speakers is longer than the wavelength of the sound emitted from the speakers, the sounds emitted from adjacent speakers will overlap, causing glowing lobes, which are sound radiation in directions other than the sound axis of the speakers. Such glowing lobes are a factor that hinders narrow directivity.

[0051] Therefore, in this embodiment, in the speaker array of the audio device 300, the positions of the speakers 302 in the vertical direction are staggered. By staggering the vertical direction in this way, it is possible to suppress grating lobes in the direction perpendicular to the road surface (up and down direction) and to increase the narrow directivity in the horizontal plane parallel to the road surface. Since grating lobes occur due to the relationship between the wavelength and the speaker interval as well as the regular periodic arrangement of the speakers, their occurrence may be prevented by a method that can suppress them most effectively, such as random arrangement other than the staggered arrangement. By weighting the electric signals applied to the speakers of ch1 to ch10 and staggering them as described above, it is possible to efficiently deliver the warning sound to the general vehicle VHG that is the target of the warning, and it is also possible to prevent the warning sound from being heard as noise around expressways where traffic control zones are set up due to the narrow directivity of the radiated acoustic signal. The width by which adjacent speakers 302 are shifted in the vertical direction is not limited to half the width of the speakers 302, and may be set, for example, so as to most effectively suppress grating lobes.

[0052] FIG. 5 shows an example of a case where the acoustic device 300 having the speaker array formed thereon as in FIG. 3 above is loaded onto a work vehicle VHW. In the figure, an example is shown in which the acoustic device 300 is loaded onto a van-type work vehicle VHW. In this way, the acoustic device 300 of this embodiment can be sized to fit into the bed of a van-type vehicle by selecting, for example, the size of the speaker. By making the size fit into the bed of a van-type vehicle, for example, the acoustic device 300 can be used even in rainy weather. In addition, if the size of the acoustic device 300 is about this level, it can be loaded onto the bed of a small truck with a hood, and the acoustic device 300 can be used even in rainy weather.

[0053] The acoustic device 300 mounted on the work vehicle VHW may be attached so as to be fixed to the work vehicle VHW, or may be attached so as to be detachable. It should be noted that the work vehicle VHW is not limited to the above-mentioned van type or small truck with a hood, and the acoustic device 300 may be loaded onto a vehicle, for example, that has a sign or the like on the loading platform to indicate that work is in progress, etc.

[0054] Although not shown in the figure, the work vehicle VHW may also be equipped with an acoustic control device 200. In this case, the acoustic control device 200 may be operated by power supplied from a battery provided in the work vehicle VHW. The acoustic control device 200 may also be operated by external power from a generator or the like.

[0055] FIG. 6 shows an example of the configuration of a signal processing system in the warning sound processor 202. As shown in FIG. The warning sound processing unit 202 in the figure includes a signal generator 221, a phase shifter 222, signal processing units 223 (223-1 to 223-4), and amplifier circuits 224 (224-11 to 224-15, 224-21 to 224-25, 224-31 to 224-35, and 224-41 to 224-45).

[0056] The signal generator 221 generates an acoustic signal as a warning sound. Phase shifter 222 changes the phase (θ) of the acoustic signal generated by signal generator 221, thereby changing the directivity in elevation and depression angles of the sound emitted from speaker 302. Phase shifter 222 can output acoustic signals with different phases, for example, ±0°, ±5°, ±10°, and ±15°, corresponding to each of signal processing units 223-1 to 223-4.

[0057] The signal processing units 223 (223-1 to 223-4) correspond to the four speaker array units R#1 to R#4, respectively. The signal processor 223 sets speaker driving voltages (gain, level) according to weightings set corresponding to ch1 to ch10 for the phase-shifted acoustic signal input from the phase shifter 222. Specifically, the signal processor 223 sets speaker driving voltages (gain, level) according to predetermined weightings that decrease in the order of channel combinations: [ch5, ch6], [ch4, ch7], [ch3, ch8], [ch2, ch9], and [ch1, ch10]. By setting the speaker driving voltages in this manner, each of the speakers 302 can be driven to a volume corresponding to the set weighting. The signal processor 223 may further perform sound quality adjustment and the like.

[0058] The amplifier circuits 224 are configured to supply speaker driving currents obtained by amplifying the signals output from the corresponding signal processors 223 to the two speakers 302 provided for each of the two corresponding channels. By setting the speaker driving voltage in this manner, each of the speakers 302 can be driven to a volume corresponding to the set weighting.

[0059] For example, air above a road is prone to temperature differences in the vertical direction. In other words, the temperature of the air at a height close to the road becomes higher than the air at a height away from the road because the road is heated by the heat of the sun, so there is a difference in temperature in the vertical direction. Since the speed of sound c and air temperature t have the relationship expressed by the following formula 1, sound waves have the tendency to bend from higher air temperatures to lower air temperatures. c = 331 + 0.6 t [m / s] (Equation 1)

[0060] Acoustic device 300 may be configured to emit sound with directivity that is approximately parallel to the road in the vertical direction (elevation and depression angles) as a standard. However, as the temperature difference in the vertical direction on the road increases as described above, the propagation direction of the sound emitted from acoustic device 300 changes to curve upward. For this reason, in a situation where the temperature difference is equal to or greater than a certain level, the sound emitted from acoustic device 300 reaches the upper side of the target general vehicle, making it difficult for the driver to hear the warning sound.

[0061] The warning sound processor 202 can set the directivity in the up and down directions (elevation and depression angles) of the sound radiated from the entire speaker array by signal processing such as phase shifting and delay in the signal processor 222 . Therefore, warning sound processor 202 is configured to set the directivity in the up and down direction (elevation and depression angles) of the sound radiated from the entire speaker array based on the temperature difference (air temperature difference on the road (one example of a setting change condition)) detected by each of sensors 401-1 and 401-2. Specifically, when the air temperature difference on the road is equal to or less than a threshold, warning sound processor 202 sets signal processing parameters related to phase shift, delay, etc. in signal processor 222 so that sound is radiated with directivity based on the elevation and depression angles set as standard. On the other hand, when the air temperature difference on the road is greater than the threshold, warning sound processor 202 sets signal processing parameters related to phase shift, delay, etc. in signal processor 222 so that sound is radiated with directivity changed to a predetermined angle downward from the elevation and depression angles set as standard.

[0062] In addition, the warning sound processing unit 202 may change the directivity at the elevation / depression angles in multiple stages according to the temperature difference on the road, rather than switching the directivity at the elevation / depression angles in two stages as described above, or may change the directivity at the elevation / depression angles continuously.

[0063] In addition, in situations where the road gradient in the area where the traffic control zone is set up changes relatively significantly, if the directionality based on the standard elevation and depression angles is maintained, the radiated sound will reach above or below the target general vehicle, making it difficult for the driver to hear. Therefore, the warning sound processor 202 may change the directivity of the sound emitted from the speaker array in terms of elevation and depression angles depending on the gradient of the road in the area where the traffic restriction zone is set up.

[0064] Setting the directivity at the elevation and depression angles of the sound according to the gradient of the road may be performed by manually changing the signal processing unit 222 in the warning sound processing unit 202 according to the gradient of the road on which the acoustic device 300 is installed (one example of a condition for changing the settings), or the signal processing unit 222 corresponding to a specific speaker 302 may be configured to change the signal processing settings such as phase shift and delay based on the measured angle of the gradient of the road.

[0065] Furthermore, the warning sound processor 202 may change the directivity of the sound emitted from the speaker array in terms of elevation and depression angles, depending on both the air temperature difference on the road and the gradient of the road.

[0066] 6 is configured to drive the speakers in units of channels along the vertical direction. However, when it is necessary to perform processing of the audio signal such as phase shifting and delay in units of speaker array units L along the horizontal direction in changing the directivity in the elevation and depression angles, the warning sound processing unit 202 may be configured to process the audio signal in units of speaker array units L. To this end, the warning sound processing unit 202 may be configured to include a signal processing unit 222 and an amplifier circuit 223 for each speaker 302, for example.

[0067] Furthermore, when changing the directivity of the speaker array in terms of elevation and depression angles, instead of processing the acoustic signal, the orientation of the speaker 302 itself may be physically changed so that the sound axis of the speaker 302 is shifted in the vertical direction.

[0068] For this purpose, for example, actuators capable of changing the sound axis in the vertical direction may be provided for all or a predetermined part of the speakers 302 forming the speaker array of the acoustic device 300. The acoustic control device 200 may control the actuators corresponding to all or a part of the speakers in the speaker array so that the directivity is achieved with a desired elevation / depression angle according to the temperature difference on the road, the gradient of the road, and the like.

[0069] The sound control device 200 may store directivity setting information that associates a specific time of the year (which may be a period specified by a date, for example) created based on the time of year (season) and the temperature difference on the road with the elevation and depression angles of the sound. In this case, the warning sound processing unit 202 of the sound control device 200 may obtain the elevation and depression angles of the sound associated with the time including the current date and time from the directivity setting information, and perform control so that the directivity becomes the elevation and depression angles of the obtained sound.

[0070] Furthermore, based on the fact that temperature differences on roads vary depending on weather even within the same season, the directivity setting information may be structured to store sound elevation and depression angles corresponding to weather conditions such as sunny, cloudy, and rainy for each time period. In this case, the warning sound processing unit 202 may acquire weather information, for example, through an input operation by the operator or by accessing a website that provides weather information on a network. The warning sound processing unit 202 may execute control so that the directivity of the sound elevation and depression angles stored in the directivity setting information corresponds to the time period including the current date and time and the acquired weather information.

[0071] The sound control device 200 may be configured to determine whether or not a traffic jam has occurred, for example, in an upstream portion of a traffic-controlled area on a road, based on the detection output of the vehicle detection device 100. When a traffic jam has occurred, the possibility that a general vehicle will enter the traffic-controlled area is quite low. Therefore, when it is determined that a traffic jam has occurred, the sound control device 200 may control the sound device 300 not to output a warning sound. [Explanation of symbols]

[0072] 100 Vehicle detection device 200 Sound control device 201 Communications Department 202 Warning sound processing section 224 (224-11~224-15, 224-21~224-25, 224-31~224-35, 224-41~224-45) Amplification circuit 300 Sound equipment 302 Speaker 400 Temperature Sensor

Claims

1. an acoustic device including a speaker array in which a predetermined number of speakers are arranged in a horizontal direction and a predetermined number of speakers are arranged in a vertical direction; an acoustic control device that drives each of the speakers to emit sound; In the speaker array, a speaker in one speaker arrangement section and a speaker in another speaker arrangement section adjacent to the one speaker arrangement section are arranged such that their positions in the vertical direction are shifted from each other by a predetermined distance, the acoustic control device drives each of the speakers in the speaker array so that a sound level decreases from the center to the edge in a horizontal direction of the speakers in the speaker arrangement section; A warning system that sets directivity in elevation and depression angles of sound radiated from the speaker array based on predetermined change conditions.

2. 2. The warning system according to claim 1, wherein the acoustic control device sets directivity in elevation and depression angles of the sound radiated from the speaker array based on a difference in air temperature in a height direction above the road surface.

3. Further, a sensor is provided for measuring air temperature at each of a plurality of measurement points having different heights relative to the road surface; 3. The warning system according to claim 2, wherein the acoustic control device sets directivity in elevation and depression angles of the sound radiated from the speaker array based on the difference in air temperatures measured at the plurality of measurement points.

4. 2. The warning system according to claim 1, wherein the acoustic control device sets directivity in elevation and depression angles of the sound radiated from the speaker array based on the gradient of a road on which the acoustic device is installed.

5. 5. The warning system according to claim 2, wherein the acoustic control device sets directivity in elevation and depression angles of sound by signal processing of acoustic signals supplied to speakers in the speaker array.

6. 2. The warning system of claim 1, wherein the speaker is a horn speaker.

7. A vehicle detection device for detecting a vehicle traveling on a road is further provided, The warning system according to claim 1 , wherein the acoustic control device drives the speaker in response to the vehicle detection device detecting a vehicle.

8. The warning system according to claim 7, wherein the vehicle detection device is adapted not to detect vehicles traveling in the opposite lane of a road on which the vehicle is to be detected.

9. 9. The warning system of claim 8, wherein the vehicle detection device detects a vehicle based on reflection of emitted light, radio waves, or ultrasonic waves, and determines whether to enable or disable vehicle detection based on the return time of the emitted light, radio waves, or ultrasonic waves.

10. A vehicle equipped with an acoustic device in a warning system according to any one of claims 2 to 4.

11. A vehicle equipped with the sound device in the warning system according to claim 5.

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