JPH11139205A - Control device of alarm sound - Google Patents

Abstract

PROBLEM TO BE SOLVED: To set a proper alarm sound according to a noise level without generating an unnecessarily large alarm sound. SOLUTION: A CPU subtracts the volume of alarm sound from the volume of external sound and extracts only the volume of noise. When the extracted volume of noise is large the volume of noise is multiplied by an adding directional coefficient k3 to set the volume regulating ratio R of alarm sound, and the volume of alarm sound is consequently added by the volume regulating ratio R to set the volume of alarm sound. When the extracted volume of noise is low, to the contrary, the volume of noise is multiplied by the subtracting directional adding coefficient k3 to set the volume regulating ratio R of alarm sound, and the volume of alarm sound is consequently subtracted by the volume regulating ratio R to set the volume of alarm sound.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a warning sound control device, for example, a warning sound control device mounted on an automatic guided vehicle traveling in factory equipment.

[0002]

2. Description of the Related Art Japanese Unexamined Patent Application Publication No. 64-77309 discloses an alarm sound control device mounted on an automatic guided vehicle, which detects when an automatic guided vehicle enters an area of ambient sound higher than a minimum volume level. When an alarm sounds at a volume higher than the ambient sound volume level and enters the area of the ambient sound lower than the minimum volume level,
One that emits an alarm sound at the lowest volume level is disclosed.

[0003]

However, in the above-mentioned prior art, for example, when the noise level becomes small, the sound mainly detected as the ambient sound becomes an alarm sound emitted from the automatic guided vehicle. Is set to a higher volume based on the volume of the alarm sound issued by the user. In this case, although the noise is low, the volume of the alarm sound is set to be higher than necessary, so that the alarm sound may be very uncomfortable for the worker.

The present invention has been made in view of the above problems, and an object of the present invention is to provide an alarm sound control device that can quickly follow a change in noise and can emit an appropriate alarm sound according to the noise. is there.

[0005]

SUMMARY OF THE INVENTION To solve the above problems,
In order to achieve the object, a warning sound control device according to the present invention has the following configuration. That is, external sound detecting means for detecting an external sound comprising an alarm sound and noise, noise extracting means for removing an alarm sound from the external sound detected by the external sound detecting means, and noise extracted by the noise extracting means. Volume setting means for setting the volume of the alarm sound based on the above.

[0006] Preferably, the noise extracting means includes:
The volume of the noise is extracted by frequency analysis of the external sound.

Preferably, the volume setting means includes:
A predetermined volume is added to the volume of the noise to set the volume of the alarm sound.

Preferably, a lower limit value is provided for the volume of the alarm sound.

Preferably, the volume of the alarm sound is:
It is corrected according to the time zone.

[0010] Preferably, the volume of the alarm sound is:
It is corrected when an obstacle is detected.

Preferably, the volume of the alarm sound is:
It is corrected in the increasing direction when an obstacle is detected.

Preferably, the device is mounted on an automatic guided vehicle.

Preferably, the volume of the alarm sound is:
The correction is made according to the traveling speed of the automatic guided vehicle.

Preferably, the volume of the alarm sound is:
As the traveling speed of the automatic guided vehicle increases, the correction is made in the increasing direction.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments according to the present invention will be described in detail with reference to the accompanying drawings.

[Control Device of Alarm Sound] First, a control device of an alarm sound according to the present embodiment will be described.

FIG. 1 is an external view of an automatic guided vehicle equipped with an alarm sound control device according to an embodiment of the present invention.

As shown in FIG. 1, the automatic guided vehicle 1 has an AUTO
It is called MATIC GUIDED VEHICLE (abbreviated as AGV), and is provided to supply parts to an assembly robot in factory equipment or the like, or to collect and transfer assembled products to another. The automatic guided vehicle 1 is driven by a motor using a battery power supply or the like, and is operated in a factory facility via a wireless device, or is automatically operated by a program. The automatic guided vehicle 1 is driven while sounding a warning sound to call attention of an operator while traveling in factory equipment.

A speaker 2 that emits an alarm sound, an obstacle sensor 3 that detects an obstacle or the like existing in front, and left and right microphones 4 for inputting external sounds are provided at the lower front part of the automatic guided vehicle 1.
a, 4b are provided. The obstacle sensor 3 is a device using infrared rays or the like. The left and right microphones 4a, 4b input the noise around the automatic guided vehicle 1 and the alarm sound emitted from the speaker 2 as external sounds.

An operation switch group 5 and an indicator group 6 are provided on the upper front of the automatic guided vehicle 1. The operation switches 5 are provided for switching the type of alarm sound of the automatic guided vehicle 1 and for manually stopping / restarting the operation. The indicator group 6 is illuminated so as to prompt the worker's attention by hearing with an alarm sound, and to visually prompt the worker's attention. It is also turned on when the remaining battery power is insufficient.

A wireless communication device 7 is provided at a rear portion of the automatic guided vehicle 1, and can be remotely controlled in factory equipment.

The automatic guided vehicle 1 has left and right drive wheels 8 and 9 as front wheels and left and right driven wheels 10 and 11 as rear wheels. The left and right driving wheels 8 and 9 are driven by left and right motors 12 and 13. The left and right driving wheels 8 and 9 are steering wheels.

At the lower part of the automatic guided vehicle 1, a left and right motor 1
A guide sensor 14 is provided below 2, 13 and a position sensor 15 is provided laterally between the left and right driving wheels 8, 9 and the left and right driven wheels 10, 11. The guide sensor 14 is provided to detect whether the vehicle is traveling on a predetermined track in the factory equipment, and the position sensor 15 is provided to detect whether the vehicle is at a predetermined stop position. I have. Each of the guide sensor 14 and the position sensor 15 is a detection device using magnetism.

[Control Circuit Configuration of Alarm Sound Control Device] Next, a control circuit configuration of the alarm sound control device according to the present embodiment will be described. FIG. 2 is a diagram showing a control circuit configuration of the alarm sound control device according to the embodiment of the present invention.

As shown in FIG. 2, in the alarm sound control device according to the present embodiment, a central processing unit (CPU) 21 controls the entire automatic guided vehicle according to a remote control command from an operator or an automatic driving program. The CPU 21 is provided with a ROM 22 for storing an automatic driving program, data of the volume and type of alarm sound, or a RAM 23 for temporarily storing the automatic driving program, traveling speed data, position data, and the like.

The CPU 21 controls the operation switch group 5 and the indicator group 6. Further, the CPU 21 receives external sounds input from the left and right microphones 4 a and 4 b via an amplifier circuit 24, receives detection signals from the guide sensor 14 and the position sensor 15, and further receives signals via the wireless communication device 7. A remote control signal is input. Left and right motor 1
3 and 12 are driven via left and right motor drivers 26 and 25. The alarm sound is output from the speaker 2 via the volume setting circuit 27.

The amplifying circuit 24 converts the external sound input from the left and right microphones 4a and 4b into an electric signal, amplifies it, and
Output to U21. Left and right motor drivers 26 and 25 are
The left and right motors 13 and 12 are driven according to a drive signal output from the CPU 21. The volume setting circuit 27 includes a CPU 2
An alarm sound of a predetermined volume is generated from the speaker 2 according to the audio signal from the speaker 1.

[Method of Controlling Alarm Sound] Next, a method of controlling an alarm sound according to the present embodiment will be described.

In the following description, the automatic guided vehicle 1 is abbreviated as AGV1 for convenience of explanation.

<Alarm sound change processing by remote control> FIG.
4 is a flowchart showing a method of changing the volume of the alarm sound by remote control as a first embodiment of the present invention.

As shown in FIGS. 2 and 3 described above, when the process is started, in step S2, the CPU 21 sets the volume set value of the alarm sound by the remote operation signal received via the wireless communication device 7. Is entered. In step S4, the CP
U21 temporarily stores in RAM 23 the volume set value of the alarm sound input in step S2. In step S6,
It waits for the start command signal of AGV1 to be input to CPU 21 by the remote control signal. When a start command signal is input to the CPU 21 in step S6 (YE in step S6).
S), and proceed to step S8. In step S8, the CPU
Reference numeral 21 drives the left and right motors 13 and 12 to run the AGV 1 and outputs an alarm sound via the speaker 2. In step S10, if a remote control signal is input to the CPU 21 via the wireless communication device 7 (step S1).
If the answer is "0" (YES in step S10), the process proceeds to step S12.
Proceed to 8.

In step S12, the CPU 21 reads out the volume set value of the alarm sound from the remote control signal received in step S10. In step S14, the CPU 21 adjusts the volume of the alarm sound according to the volume set value read in step S12, and outputs a volume output signal of the alarm sound to the volume setting circuit 27. In step S16, the volume setting circuit 27 amplifies the volume output signal of the alarm sound and outputs the amplified signal via the speaker 2.

In step S18, if a stop command signal for AGV1 is input to CPU 21 by a remote control signal (YES in step S18), the flow proceeds to step S20. In step S20, the CPU 21
3 and 12 are stopped to stop the running of the AGV 1 and the output of the alarm sound through the speaker 2 is stopped. On the other hand, in step S18, if the stop command signal of AGV1 has not been input to CPU 21 by the remote control signal (NO in step S18), the process returns to step S8, and the processes in and after step S8 are repeated.

<Process of Changing Alarm Sound by Time Zone> FIG. 4 is a flowchart showing a method of changing the volume of the alarm sound according to the time zone as a second embodiment of the present invention.

As shown in FIGS. 2 and 4 described above, when the process is started, in step S 32, the CPU 21 operates the operation switch group 5 so that the CPU 21 gives the CPU 21 a volume change time for the alarm sound and a volume setting. A value is entered. Step S
In 34, the CPU 21 temporarily stores the volume change time and volume set value of the alarm sound input in step S 32 in the RAM 23. In step S36, the CPU 21 waits for the start command signal of the AGV1 to be input to the CPU 21 by the operation switch group 5. When a start command signal is input to CPU 21 in step S36 (YES in step S36), the process proceeds to step S38. In step S38, the CPU 21 drives the left and right motors 13, 12 to drive the AGV 1, and outputs an alarm sound via the speaker 2. In step S40, the CPU 21 determines whether or not the alarm sound volume change time preset in step S32 has come.
If the time has come to change the volume in step S40 (YES in step S40), the process proceeds to step S42. If the time has not reached (NO in step S40), the process proceeds to step S48 described later.

In step S42, the CPU 21 reads out the volume change time and volume set value of the alarm sound stored in step S34. In step S44, the CPU 21 adjusts the volume of the alarm sound according to the volume setting value read in step S42, and outputs a volume output signal of the alarm sound to the volume setting circuit 27. In step S46, the volume setting circuit 27 amplifies the volume output signal of the alarm sound and outputs the amplified signal via the speaker 2.

In step S48, if a stop command signal of the AGV 1 is input to the CPU 21 by the operation switch group 5 (YES in step S48), the process proceeds to step S50. In step S50, the CPU 21
3 and 12 are stopped to stop the running of the AGV 1 and the output of the alarm sound through the speaker 2 is stopped. On the other hand, in step S48, the operation switches 5
If the stop command signal of the AGV1 is not input (NO in step S48), the process returns to step S38, and the processes in and after step S38 are repeated.

<Alarm Sound Change Processing by Obstacle Detection> FIG. 5 is a flowchart showing a method of changing the volume of the alarm sound by obstacle detection as a third embodiment of the present invention.

As shown in FIGS. 2 and 5 described above, when the process is started, in step S62, the volume of the alarm sound at the time of detecting an obstacle is provided to the CPU 21 by operating the operation switch group 5 by the operator. The set value is entered. Step S
In step 64, the CPU 21 temporarily stores in the RAM 23 the volume set value of the alarm sound at the time of detecting the obstacle input in step S62. In step S66, the CPU 21 waits for the start command signal of the AGV1 to be input by the operation switch group 5 to the CPU 21. When a start command signal is input to CPU 21 in step S66 (YES in step S66), the process proceeds to step S68. In step S68, the CPU 21 drives the left and right motors 13 and 12 to drive the AGV 1, and outputs an alarm sound via the speaker 2. In step S70, the CPU 21 determines whether an obstacle has been detected based on the detection signal from the obstacle sensor 3. If an obstacle is detected in step S70 (Y in step S70)
ES), the process proceeds to step S72, and if no obstacle is detected (NO in step S70), step S7 described later.
Proceed to 8.

In step S72, the CPU 21 reads out the alarm sound volume set value stored in step S64.
In step S74, the CPU 21 adjusts the volume of the alarm sound according to the volume set value read in step S72,
The volume output signal of the alarm sound is output to the volume setting circuit 27. In step S76, the volume setting circuit 27 amplifies the volume output signal of the alarm sound and outputs the amplified signal via the speaker 2.

In step S78, if the stop command signal of AGV1 is input to CPU 21 by operation switch group 5 (YES in step S78), the process proceeds to step S80. In step S80, the CPU 21
3 and 12 are stopped to stop the running of the AGV 1 and the output of the alarm sound through the speaker 2 is stopped. On the other hand, in step S78, the operation switches 5
If the stop command signal of AGV1 has not been input (NO in step S78), the process returns to step S68 and repeats the processing from step S68.

<Process of Changing Alarm Sound Based on Traveling Speed> FIG.
9 is a flowchart showing a method of changing the volume of the alarm sound according to the traveling speed of the automatic guided vehicle as a fourth embodiment of the present invention.

As shown in FIGS. 2 and 6 described above, when the process is started, in step S92, the operation of the operation switch group 5 by the operator causes the CPU 21 to output the volume of the alarm sound corresponding to the traveling speed. The set value is entered. In step S94, the CPU 21 temporarily stores in the RAM 23 the volume set value of the alarm sound corresponding to the traveling speed input in step S92. In step S96, the control unit 5 waits for the activation command signal of the AGV1 to be input to the CPU 21 by the operation switch group 5. When a start command signal is input to CPU 21 in step S96 (YES in step S96), the process proceeds to step S98. In step S98, the CPU 21 drives the left and right motors 13 and 12 to drive the AGV 1 and outputs an alarm sound via the speaker 2. In step S100, CPU 21 determines whether or not the traveling speed of AGV1 has been changed. If the traveling speed is changed in step S100 (YE in step S100)
S), proceeding to step S102, if not changed (NO in step S100), step S10 to be described later
Proceed to 8.

In step S102, the CPU 21 reads out the volume set value of the alarm sound corresponding to the traveling speed stored in step S94. In step S104, the CPU 21
Adjusts the volume of the alarm sound in accordance with the volume setting value read in step S102, and outputs a volume output signal of the alarm sound to the volume setting circuit 27. In step S106, the volume setting circuit 27 amplifies the volume output signal of the alarm sound and outputs the amplified signal via the speaker 2.

In step S108, if a stop command signal for the AGV1 is input to the CPU 21 by the operation switch group 5 (YES in step S108), the process proceeds to step S1.
Go to 10. In step S110, the CPU 21 stops the left and right motors 13 and 12 to stop the running of the AGV 1, and stops outputting the alarm sound via the speaker 2. On the other hand, if the stop command signal of the AGV 1 is not input to the CPU 21 by the operation switch group 5 in step S108 (NO in step S108), step S9 is performed.
8 and the processing from step S98 is repeated. [Volume Adjustment Processing of Alarm Sound by Volume] FIG. 7 is a flowchart showing a volume adjustment processing of alarm sound by volume as a first embodiment of the present invention.

As shown in FIGS. 2 and 7, when the process is started, in steps S122 and S124, C
The PU 21 amplifies the voltage value E of the external sound input from the left and right microphones 4a and 4b to E × k1 (k1> 0) by the amplifier circuit 24 and inputs the amplified voltage. In step S126, the CPU 21
Inputs a volume output signal of the alarm sound output to the volume setting circuit 27. In step S128, the CPU 21
The voltage value S of the volume output signal is adjusted to S × k2. In step S130, the CPU 21 calculates the voltage value N of the noise from Expression 1 below.

N = E × k1−S × k2 (1) In step S132, the noise voltage value N calculated in step S130 is multiplied by a predetermined adjustment coefficient k3, and the volume adjustment rate of the alarm sound is calculated. R is set from Equation 2 below.

R = N × k3 (2) In step S134, the voltage value S of the volume output signal is changed to the volume adjustment rate R and the correction coefficient α set in step S132.
From the following equation (3).

A = S × R × α (3) In step S136, the voltage value A of the volume output signal adjusted in step S134 is amplified by the following equation (4).

Av = A × k4 (4) The CPU 21 outputs the voltage value Av of the volume output signal amplified in step S136 from the speaker 2 via the volume setting circuit 27 as an alarm sound. The correction coefficient α in step S134 is a value for correcting the voltage value S of the volume output signal in the increasing direction or the decreasing direction according to the time period, obstacle detection, and traveling speed shown in FIGS. is there. That is, the volume of the alarm sound is corrected in the increasing direction when an obstacle is detected, or is corrected in the increasing direction as the traveling speed of the AGV 1 increases.

FIG. 8 is a diagram for explaining the processing shown in FIG.

As shown in FIG. 8, the CPU 21 subtracts the volume (voltage value) of the alarm sound from the volume (voltage value) of the external sound (noise + alarm sound) to extract only the volume (voltage value) of the noise. I do. And if the volume of the extracted noise is high,
The volume of this noise is multiplied by the addition / subtraction coefficient k3 in the addition direction to set a volume adjustment rate R of the alarm sound, and as a result, the volume of the alarm sound is added by the volume adjustment rate R to set the volume of the alarm sound, Conversely, when the volume of the extracted noise is low, the volume of the noise is multiplied by the addition / subtraction coefficient k3 in the subtraction direction to set the volume adjustment rate R of the alarm sound, and as a result, the volume of the alarm sound is adjusted. Rate R
Set the volume of the alarm sound by subtracting only. Further, a lower limit value is set for the volume output signal S, and the volume of the alarm sound is set so as not to fall below the lower limit value.

As described above, in adjusting the volume of the alarm sound based on the volume, the volume of the alarm sound can be set to the minimum volume according to the volume level of the noise extracted from the external sound.
[Volume Adjustment Processing of Alarm Sound by Frequency Analysis] FIG. 9 is a flowchart showing a sound volume adjustment processing of alarm sound by frequency analysis as a second embodiment of the present invention.

As shown in FIGS. 2 and 9, when the process is started, in steps S142 and 144, C
The PU 21 amplifies the voltage value E of the external sound input from the left and right microphones 4a and 4b to E × k1 (k1> 0) by the amplifier circuit 24 and inputs the amplified voltage. In step S146, the CPU 21
Performs a frequency analysis for calculating a voltage value for each frequency i from the voltage value E of the external sound input in step S142 as in the following Expression 5.

ELi = Fi (E × k1) (5) i = 0 to ni: type of frequency In step S148, the CPU 21 sets the volume setting circuit 2
7, a volume output signal S of the alarm sound is input. In step S150, CPU 21 adjusts voltage value S of the volume output signal to S × k2. In step S152,
The CPU 21 determines in step S150 as shown in the following Expression 6.
A frequency analysis is performed to calculate a voltage value for each frequency i from the voltage value S of the volume output signal input in step (1).

SLi = Fi (S × k2) (6) i = 0 to ni: frequency type In step S154, the CPU 21 determines the noise voltage value N
Is calculated from the following equation 7 for each frequency i.

NLi = ELi-SLi (7) i = 0 to ni: frequency type In step S156, the noise waveform NLi calculated for each frequency is synthesized by the following equation 8.

N = NL1 + NL2 + NL3 +... + NLi-1 + NLi (8) In step S158, the synthesized voltage value N of the noise calculated in step S156 is multiplied by a predetermined adjustment coefficient k3, and the volume adjustment rate R of the alarm sound is calculated. Is set from Equation 9 below.

R = N × k3 (9) In step S160, the voltage value S of the volume output signal is set to the volume adjustment rate R and the correction coefficient α set in step S158.
From the following equation (10).

A = S × R × α (10) In step S162, the voltage value A of the volume output signal adjusted in step S160 is amplified by the following equation (11).

Av = A × k4 (11) The CPU 21 outputs the voltage value Av of the volume output signal amplified in step S162 from the speaker 2 as a warning sound via the volume setting circuit 27. The correction coefficient α in step S160 is a value for correcting the voltage value S of the volume output signal in the increasing direction or the decreasing direction in accordance with the time period, obstacle detection, and traveling speed shown in FIGS. is there. That is, the volume of the alarm sound is corrected in the increasing direction when an obstacle is detected, or is corrected in the increasing direction as the traveling speed of the AGV 1 increases.

FIG. 10 is a diagram for explaining the processing shown in FIG.

As shown in FIG. 10, the CPU 21 analyzes the volume (voltage value) of the external sound (noise + alarm sound) and the volume (voltage value) of the alarm sound for each frequency, and The volume of the alarm sound is subtracted for each frequency from the volume, and only the volume of the noise is extracted for each frequency. Then, after synthesizing the volume of the extracted noise of each frequency, if the volume of the synthesized noise is high, the volume of this noise is multiplied by the addition / subtraction coefficient k3 in the addition direction, and the volume adjustment rate R of the alarm sound is calculated. And set
As a result, the volume of the alarm sound is added by the volume adjustment rate R to set the volume of the alarm sound. Conversely, when the volume of the extracted noise is low, the addition / decrease coefficient k3 in the subtraction direction is added to the volume of this noise. The multiplication is performed to set the volume adjustment rate R of the alarm sound. As a result, the volume of the alarm sound is subtracted by the volume adjustment rate R to set the volume of the alarm sound. Further, a lower limit value is set for the volume output signal S, and the volume of the alarm sound is set so as not to fall below the lower limit value.

As described above, in the volume adjustment of the alarm sound by the frequency analysis, the volume of the external sound, the volume of the alarm sound, and the volume of the noise are calculated for each frequency, so that a more accurate volume can be detected. it can.

It should be noted that the present invention can be applied to a modification or change of the above embodiment without departing from the spirit thereof.

[0066]

As described above, according to the present invention, an external sound comprising an alarm sound and noise is detected, the alarm sound is removed from the detected external sound, and based on the extracted noise,
By setting the volume of the alarm sound, it is possible to quickly follow a change in the noise, and to emit an appropriate alarm sound according to the noise.

[0067]

[Brief description of the drawings]

FIG. 1 is an external view of an automatic guided vehicle on which an alarm sound control device according to an embodiment of the present invention is mounted.

FIG. 2 is a diagram showing a control circuit configuration of the alarm sound control device according to the embodiment of the present invention.

FIG. 3 is a flowchart showing a method of changing the volume of an alarm sound by remote control as the first embodiment of the present invention.

FIG. 4 is a flowchart illustrating a method of changing the volume of an alarm sound according to a time zone as a second embodiment of the present invention.

FIG. 5 is a flowchart illustrating a method of changing the volume of an alarm sound by detecting an obstacle as a third embodiment of the present invention.

FIG. 6 is a flowchart illustrating a method for changing the volume of an alarm sound according to the traveling speed of an automatic guided vehicle as a fourth embodiment of the present invention.

FIG. 7 is a flowchart illustrating a volume adjustment process of a warning sound based on a volume according to the first embodiment of the present invention.

FIG. 8 is a diagram for explaining the processing shown in FIG. 7;

FIG. 9 is a flowchart illustrating a process of adjusting a volume of an alarm sound by frequency analysis as a second embodiment of the present invention.

FIG. 10 is a diagram for explaining the processing shown in FIG. 9;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Automatic guided vehicle (AGV) 2 ... Speaker 3 ... Obstacle sensor 4a, 4b ... Left and right microphone 5 ... Operation switch group 6 ... Indicator group 7 ... Wireless communication device 14 ... Guide sensor 15 ... Position sensor

Claims (10)

[Claims] An external sound detection unit configured to detect an external sound including an alarm sound and a noise; a noise extraction unit configured to remove an alarm sound from the external sound detected by the external sound detection unit; And a sound volume setting means for setting a sound volume of the alarm sound based on the noise. 2. The alarm sound control device according to claim 1, wherein the noise extraction unit extracts a volume of the noise by frequency analysis of the external sound. 3. The alarm sound control device according to claim 2, wherein the sound volume setting means adds a predetermined sound volume to the noise sound volume to set the sound volume of the alarm sound. 4. The alarm sound control device according to claim 2, wherein a lower limit value is provided for a volume of the alarm sound. 5. The alarm sound control device according to claim 4, wherein the volume of the alarm sound is corrected according to a time zone. 6. The alarm sound control device according to claim 4, wherein the volume of the alarm sound is corrected when an obstacle is detected. 7. The alarm sound control device according to claim 6, wherein the volume of the alarm sound is corrected in an increasing direction when an obstacle is detected. 8. The alarm sound control device according to claim 1, wherein the device is mounted on an automatic guided vehicle. 9. The volume of the alarm sound is corrected according to a traveling speed of the automatic guided vehicle.
2. The alarm sound control device according to claim 1. 10. The alarm sound control device according to claim 9, wherein the volume of the alarm sound is corrected in an increasing direction as the traveling speed of the automatic guided vehicle increases.