Automated guided vehicle

Abstract

An automated guided vehicle 30 comprises: a USB interface 13 that is provided on a body 30A of the automated guided vehicle 30 and allows detachable connection of a USB memory M; an obstacle sensor 12 that is provided on the body 30A of the automated guided vehicle 30 and detects an obstacle in the traveling direction of the automated guided vehicle 30 and the USB memory M connected to the USB interface 13; and a control unit 45 that, when an obstacle or the USB memory M connected to the USB interface 13 is detected by the obstacle sensor 12, provides a notification of the detection of the obstacle or the USB memory M.

Description

Automated Guided Vehicle

[0001] The present invention relates to an automated guided vehicle that travels along a travel line laid on a road surface.

[0002] As an automated guided vehicle, there is one that includes a sensor that optically or magnetically detects a travel line laid on a road surface, and a control unit that controls the travel direction of the automated guided vehicle according to the position of the travel line detected by the sensor, and also controls the travel, stop, etc. of the automated guided vehicle.

[0003] For example, in the automated guided vehicle described in Patent Document 1, a track line (travel line) is provided on the floor, and a plurality of magnetic markers are sequentially arranged along the track line. The control unit makes the automated guided vehicle travel along the track line detected by the track line detection sensor of the automated guided vehicle. Further, each time the control unit approaches each magnetic marker in sequence, it detects the approached magnetic marker by either of two marker detection sensors provided on both sides of the automated guided vehicle and counts it up, and performs travel control of the automated guided vehicle according to a command corresponding to a predetermined count-up number.

[0004] Japanese Unexamined Patent Application Publication No. 2016-115207

[0005] Here, as described above, the automated guided vehicle includes a control unit that controls the travel direction of the automated guided vehicle and also controls the travel, stop, etc. of the automated guided vehicle. This control unit performs control based on a preset program and data, and the program and data may be read from an external device such as a USB memory.

[0006] It is also conceivable to transmit the program and data from an external terminal to the automated guided vehicle by short-range communication (for example, WiFi), but in an environment such as a warehouse where the automated guided vehicle is used, a short-range communication system is not installed, and an external device such as a USB memory is often used.

[0007] However, if an external device such as a USB memory stick is connected to the main body of the automated guided vehicle (AGV) and the AGV is operated without removing the external device, there is a risk that the external device may fall off or be damaged while the AGV is in motion, or that the external device may obstruct the operation of the AGV. For this reason, it is preferable to prevent situations in which the AGV is operated without removing the external device.

[0008] Patent Document 1 describes the control of an automated guided vehicle (AGV), and therefore it is assumed that the program and data need to be updated. However, as described above, it does not have a configuration for reading the program and data from an external device such as a USB memory stick, and naturally, no measures are taken to prevent situations in which the AGV is operated without removing the external device.

[0009] Alternatively, one could consider installing a special sensor to detect the presence or absence of external devices such as USB memory sticks, thereby detecting external devices that were not removed. However, this is undesirable because it would increase the number of components.

[0010] This invention has been made in view of the above circumstances, and aims to enable the detection of the presence or absence of an external device using an existing obstacle sensor in an automated guided vehicle.

[0011] An automated guided vehicle according to one aspect of the present invention is an automated guided vehicle that travels along a travel line laid on a road surface, comprising: an obstacle sensor that detects an object to be detected in the area in front of the main body of the automated guided vehicle in the direction of travel of the automated guided vehicle; a connection part disposed at a position on the main body of the automated guided vehicle to which an external device is detachably connected, and to which the connected external device is located within the area that is the target of detection by the obstacle sensor; and a control unit that performs predetermined control when the object to be detected is detected by the obstacle sensor.

[0012] According to the present invention, the presence or absence of an external device can be detected using an existing obstacle sensor on an automated guided vehicle.

[0013] This is a schematic diagram showing the automated guided vehicle (AGV) driving system of an AGV according to one embodiment of the present invention. This is a perspective view showing the front portion of the AGV body of this embodiment. This is a plan view schematically showing the detection range of the obstacle sensor when the AGV body is viewed from above. (A) is a diagram showing the rotation of each drive wheel when the AGV is moving forward, (B) is a diagram showing the rotation of each drive wheel when the AGV is moving backward, (C) is a diagram showing the rotation of each drive wheel when the direction of the AGV is changed to the right, and (D) is a diagram showing the rotation of each drive wheel when the direction of the AGV is changed to the left. This is a block diagram showing the control system of the AGV. This is a flowchart showing the control procedure of the AGV based on the detection of an obstacle or external device in this embodiment. This is a plan view schematically showing another example of the detection range of the obstacle sensor when the AGV body is viewed from above. This is a flowchart showing the control procedure of the AGV based on the detection of an obstacle or external device in modified form 1. This is a schematic diagram showing a further embodiment of the automated guided vehicle (AGV) driving system of an AGV according to one embodiment of the present invention. This is a perspective view showing the front portion of the main body of a further embodiment of the AGV of this embodiment. This is a flowchart showing the control procedure of the AGV based on the detection of obstacles or external devices in modified form 2.

[0014] Embodiments of the present invention will be described below with reference to the drawings. In the following, directions of rotation or left / right and up / down directions may be indicated, but unless otherwise specified, these refer to directions as examples in each drawing.

[0015] Figure 1 is a schematic diagram showing an automated guided vehicle (AGV) driving system according to one embodiment of the present invention. The AGV driving system Sy shown in Figure 1 comprises a driving line 10 laid on the road surface and an AGV 30 that travels along the driving line 10.

[0016] The automated guided vehicle 30 is provided with a line sensor 11 facing the road surface and detecting the position of the travel line 10, an obstacle sensor 12 that detects obstacles in at least the travel direction of the automated guided vehicle 30, and a USB interface 13 to which a USB memory (an example of an external device) can be detachably connected. The line sensor 11 includes, for example, a CIS (Contact Image Sensor) or a CCD (Charge Coupled Device). In this embodiment, an example in which the line sensor 11 includes a CCD will be described.

[0017] The obstacle sensor 12 is, for example, a LiDAR (Light Detection And Ranging) sensor. It scans the laser light from a laser element horizontally, receives the reflected light from the object to be detected with a light sensor, and outputs a signal indicating that the object has been detected (for example, a signal indicating that reflected light has been received) and a signal indicating the distance from the obstacle sensor 12 to the object. In other words, the obstacle sensor 12 detects the presence of the object and the distance from the obstacle sensor 12 to the object. Based on these signals, the control unit 45 (Figure 5) determines that the object has been detected and the distance from the obstacle sensor 12 to the object. The control unit 45 (Figure 5) also determines the distance from the obstacle sensor 12 to the object in multiple directions centered on the LiDAR sensor, based on the point cloud data acquired by the LiDAR sensor.

[0018] Figure 2 is a magnified perspective view showing the front portion of the main body 30A of the automated guided vehicle (AGV) 30 in the direction of travel (direction of arrow A). As shown in Figure 2, an obstacle sensor 12 is provided at the corner 30B of the front portion of the main body 30A of the AGV 30 in the direction of travel. A USB interface 13 is also provided at the flat portion 30C of the front portion of the main body 30A.

[0019] Figure 3 is a plan view showing the main body 30A of the automated guided vehicle 30 as seen from above. As shown in Figure 3, the detection range a of an object to be detected by the obstacle sensor 12, centered on the obstacle sensor 12, is, for example, a range of 270°. In this example, since the obstacle sensor 12 is provided at the corner 30B of the front part of the main body 30A, the effective detection range α is a range of 225° to the left rear and in front of the corner 30B of the main body 30A. Also, the range of 45° to the right rear of the main body 30A is a blind spot for the obstacle sensor 12 and is an invalid detection range β. Therefore, the obstacle sensor 12 detects obstacles in front of and to the left rear of the main body 30A of the automated guided vehicle 30, and the distance from the obstacle sensor 12 to the obstacle. On the other hand, the obstacle sensor 12 does not detect the obstacle to the right rear of the main body 30A of the automated guided vehicle 30 in the travel direction A shown in Figure 3.

[0020] Here, the USB interface 13 is positioned on the main body 30A such that when a USB memory as an external device is connected, the USB memory will be within the effective detection range α of the object detected by the obstacle sensor 12. By providing the USB interface 13 on the flat portion 30C at the front of the main body 30A, when the USB memory M is inserted into the USB interface 13 and connected, the USB memory M protrudes forward from the main body 30A and enters the effective detection range α of the obstacle sensor 12. The obstacle sensor 12 detects the USB memory M and its distance within the effective detection range α.

[0021] As shown in Figure 1, casters (also called swivel casters) 31 are provided at each of the four corners of the bottom of the automated guided vehicle (AGV) 30. Inside the bottom of the AGV 30, four drive wheels 32 are provided spaced apart from each other in a direction perpendicular to the direction of travel of the AGV 30, and the axes of each drive wheel 32 are aligned in a straight line. Under the control of the control unit 45 (Figure 5), which will be described later, each drive wheel 32 is rotated by its respective drive motor, causing the AGV 30 to move and each caster 31 to rotate in response.

[0022] Furthermore, the four casters 31 and the four drive wheels 32 are arranged on both sides of the main body 30A of the automated guided vehicle 30, in a direction perpendicular to the direction of travel A, from the center in the width direction, and are not located in the central area in the width direction of the main body 30A.

[0023] Here, with each drive wheel 32 in contact with the floor, the drive motor for each drive wheel 32 is controlled individually, adjusting the rotation speed of the drive wheel 32 and switching the rotation direction of the drive wheel 32, causing the automated guided vehicle 30 to move. Steering control of the automated guided vehicle 30 is also performed, thereby changing the direction of travel of the automated guided vehicle 30, and consequently each caster 31 rotates in response and changes its orientation.

[0024] The rotation control of each drive wheel 32 when the automated guided vehicle 30 is in motion will be explained. Figures 4(A) to 4(D) show the rotation of each drive wheel 32 for each direction of travel when the automated guided vehicle 30 is in motion. As mentioned above, the directions shown in the explanation referring to Figure 4 are for the example shown in Figure 4. The rotation control of each drive wheel 32 shown below is performed by the control unit 45.

[0025] As shown in Figure 4(A), when the automated guided vehicle 30 is moved forward, the control unit 45 rotates the four drive wheels 32 at the same rotational speed in the direction in which the automated guided vehicle 30 moves forward (hereinafter referred to as the forward direction).

[0026] As shown in Figure 4(B), when the automated guided vehicle 30 is moved in reverse, the control unit 45 rotates the four drive wheels 32 at the same rotational speed in the direction in which the automated guided vehicle 30 is moving in reverse (hereinafter referred to as the reverse direction).

[0027] As shown in Figure 4(C), when changing the direction of the automated guided vehicle 30 to the right, the control unit 45 rotates the two left drive wheels 32 in the forward direction, and rotates the two right drive wheels 32 in the forward direction at a slower rotational speed than each of the left drive wheels 32, or stops them. At this time, the control unit 45 may set the rotational speed of the left outer drive wheel 32 to be the fastest, the rotational speed of the left inner drive wheel 32 to be the second fastest, the rotational speed of the right inner drive wheel 32 to be the third fastest, and the rotational speed of the right outer drive wheel 32 to be the slowest or stop. By appropriately setting the rotational speeds of the four drive wheels 32, the turning radius of the automated guided vehicle 30 can be changed.

[0028] As shown in Figure 4(D), when changing the direction of the automated guided vehicle 30 to the left, the control unit 45 rotates the two right drive wheels 32 in the forward direction, and rotates the two left drive wheels 32 in the forward direction at a slower rotational speed than each of the right drive wheels 32, or stops them. At this time, the control unit 45 may set the rotational speed of the right outer drive wheel 32 to be the fastest, the rotational speed of the right inner drive wheel 32 to be the second fastest, the rotational speed of the left inner drive wheel 32 to be the third fastest, and the rotational speed of the left outer drive wheel 32 to be the slowest or stop. By appropriately setting the rotational speeds of the four drive wheels 32, the turning radius of the automated guided vehicle 30 can be changed.

[0029] In this way, the control unit 45 controls the rotational speed and direction of each of the four drive wheels 32, thereby enabling the automated guided vehicle 30 (AGV) to move forward, backward, turn to the right, and turn to the left. In addition, the four casters 31 change direction according to the direction of travel of the AGV 30, providing stable support for the AGV 30 so that it can move freely. As a result, despite its simple configuration, it is possible to stably change the direction of the AGV 30 while it is in motion.

[0030] Although four drive wheels 32 are shown as an example here, it is also possible to configure the automated guided vehicle 30 (AGV) 30 with two drive wheels 32, distributed to the left and right from the center of the width direction of the main body 30A, and to control the rotation speed and rotation direction of the left and right drive wheels 32 respectively to drive the AGV 30 as shown in Figures 4(A) to (D).

[0031] Figure 5 is a block diagram showing the control system of the automated guided vehicle 30. As shown in Figure 5, the automated guided vehicle 30 includes a line sensor 11, an obstacle sensor 12, a USB interface 13, a display unit 41 consisting of a liquid crystal display or the like, a buzzer 42, each drive motor 43 that rotates each drive wheel 32, a storage unit 44, and a control unit 45.

[0032] As shown in Figure 1, the line sensor 11 is long in the width direction (direction perpendicular to the travel direction) of the main body 30A of the automated guided vehicle 30 and is positioned in the center of the main body 30A. When the automated guided vehicle 30 is transporting, the line sensor 11 is perpendicular to the travel line 10 and optically detects the position of the travel line 10 in the longitudinal direction of the line sensor 11 (width direction of the main body 30A).

[0033] The obstacle sensor 12 detects objects to be detected and their distances, such as obstacles in the direction of travel of the automated guided vehicle 30 and their distances, and the USB memory M inserted into the USB interface 13 and its distance.

[0034] The memory unit 44 is, for example, a non-volatile memory. The memory unit 44 stores control programs and data for operating the automated guided vehicle 30.

[0035] The operation unit 46 is equipped with hard keys such as a numeric keypad, an enter key, and a start key. Various instructions are input to the operation unit 46 from the user. The operation unit 46 outputs the input instructions to the control unit 45.

[0036] The control unit 45 consists of a processor, RAM (Random Access Memory), and ROM (Read Only Memory). The processor is, for example, a CPU (Central Processing Unit), an ASIC (Application Specific Integrated Circuit), or an MPU (Micro Processing Unit). The control unit 45 performs overall drive control of the automated guided vehicle 30 by executing a control program stored in the ROM or storage unit 44 on the processor.

[0037] In an automated guided vehicle 30 with this configuration, the control unit 45 determines the amount of deviation between the position of the travel line 10 in the longitudinal direction of the line sensor 11 (the width direction of the main body 30A of the automated guided vehicle 30) detected by the line sensor 11 and the center position of the line sensor 11 (the center position of the main body 30A). The control unit then controls the drive motor 43 of each drive wheel 32 to change the orientation of the automated guided vehicle 30 and control the automated guided vehicle 30 to travel along the travel line 10, so that this amount of deviation becomes "0".

[0038] Furthermore, when the obstacle sensor 12 detects an object and its distance, the control unit 45 determines, based on the output from the obstacle sensor 12, whether the distance to the object is less than or equal to a preset first threshold (for example, 1 m). If the control unit 45 determines that the distance to the object is less than or equal to the first threshold, it determines that an object (obstacle or USB memory M) has been detected. At this time, the control unit 45 does not drive the drive motors 43 of each drive wheel 32, maintaining the stopped state of the automated guided vehicle 30 or stopping the automated guided vehicle 30. The control unit 45 displays an error message indicating that an object has been detected on the display unit 41 and generates a notification sound with the buzzer 42.

[0039] Here, the control unit 45 stores the distance from the obstacle sensor 12 to the USB interface 13 as a second threshold. When the obstacle sensor 12 detects an object and its distance, the control unit 45 determines, based on the output from the obstacle sensor 12, whether the distance to the object is within a predetermined range from the second threshold. When the control unit 45 determines that the distance to the object is within a predetermined range from the second threshold, it determines that the object is a USB memory M (external device).

[0040] As described above, the memory unit 44 stores control programs and data for operating the automated guided vehicle 30. When updating these programs and data, the user inserts a USB memory stick M containing the update programs and data into the USB interface 13. The control unit 45 reads the update programs and data from the USB memory stick M and updates the control programs and data stored in the memory unit 44 based on the read update programs and data.

[0041] However, if the user operates the automated guided vehicle 30 30 with the USB memory M still connected to the main unit 30A of the automated guided vehicle 30, that is, without removing the USB memory M, there is a risk that the USB memory M may fall off or be damaged while the automated guided vehicle 30 is in motion, or that the USB memory M may obstruct the operation of the automated guided vehicle 30.

[0042] Therefore, as described above, when the obstacle sensor 12 detects an obstacle or the USB memory M inserted into the USB interface 13, the control unit 45 performs predetermined control. The predetermined control performed by the control unit 45 is to (i) maintain the stopped state of the automated guided vehicle 30 (prevent it from starting to move) or to stop the automated guided vehicle 30, and (ii) display an error message on the display unit 41 indicating that the USB memory M has been detected, or generate a notification sound with the buzzer 42.

[0043] Next, referring to the flowchart shown in FIG. 6, the control by the control unit 45 when the detected object is detected by the obstacle sensor 12 will be described.

[0044] When the control unit 45 detects the detected object and its distance by the obstacle sensor 12 (S101), it determines whether the distance to the detected object is equal to or less than the first threshold value (S102). If the distance to the detected object exceeds the threshold value (S102 "No"), the control unit 45 repeats S101 and S102, assuming that there is no problem with the running of the unmanned transport vehicle 30.

[0045] On the other hand, when the control unit 45 determines that the distance to the detected object is equal to or less than the threshold value (S102 "Yes"), it assumes that the detected object, that is, the obstacle or the USB memory M inserted into the USB interface 13 causes a problem with the running of the unmanned transport vehicle 30, and does not drive the running drive motors 43 of each drive wheel 32, and maintains the stopped state of the unmanned transport vehicle 30 or stops the unmanned transport vehicle 30 (S103). The control unit 45 causes the display unit 41 to display an error message indicating that the detected object has been detected (S104), and generates a notification sound by the buzzer 42 (S105).

[0046] As a result, when the user hears the notification sound, the user can see the error message displayed on the display unit 41 in the stopped state of the unmanned transport vehicle 30 and know the detection of the obstacle or the USB memory M as the detected object. The user removes the obstacle or removes the USB memory M from the USB interface 13, for example, and operates the operation unit 46 of the unmanned transport vehicle 30. The control unit 45 of the unmanned transport vehicle 30 resumes the running of the unmanned transport vehicle 30 according to the running resume instruction input based on the operation of the operation unit 46.

[0047] Also, when the USB memory M remains connected to the USB interface 13, the driverless transport vehicle 30 does not move. Therefore, it is possible to prevent the situation where the driverless transport vehicle 30 moves with the USB memory M not removed. Further, by providing the USB interface 13 within the detection range a of the detected object by the obstacle sensor 12, the USB memory M can be detected using the existing obstacle sensor 12. <Modification 1> In Modification 1, as shown in FIG. 7, the effective detection range α centered on the obstacle sensor 12 by the obstacle sensor 12 is divided into a first detection range α1 for detecting obstacles and a second detection range α2 for detecting the USB memory M connected to the USB interface 13. For example, when a LiDAR sensor is applied as the obstacle sensor 12, based on the point cloud data acquired by the LiDAR sensor, the detected object detected in the first detection range α1 is determined as an obstacle, and the detected object detected in the second detection range α2 is determined as the USB memory M.

[0048] The obstacle sensor 12 outputs to the control unit 45 a position signal indicating the location (direction) of the detection target in the peripheral area centered on the obstacle sensor 12, a signal indicating that a detected object has been detected, and a signal indicating the distance from the obstacle sensor 12 to the detected object. The control unit 45 stores in advance whether the position indicated by the position signal transmitted from the obstacle sensor 12 belongs to either the first detection range α1 or the second detection range α2. When the control unit 45 detects a detected object and its distance in the first detection range α1 by the obstacle sensor 12, it determines that the detected object is an obstacle. When the control unit 45 detects a detected object and its distance in the second detection range α2 by the obstacle sensor 12, it determines that the detected object is the USB memory M. When the control unit 45 determines that it is an obstacle or the USB memory M, it causes the display unit 41 to display an error message indicating the detection of the detected object, and generates a notification sound by the buzzer 42.

[0049] The flowchart shown in Figure 8 illustrates the control performed by the control unit 45 when an obstacle is detected in the first detection range α1 by the obstacle sensor 12, or when the USB memory M is detected in the second detection range α2 by the obstacle sensor 12.

[0050] When the obstacle sensor 12 detects an object to be detected and its distance in the first detection range α1 or an object to be detected and its distance in the second detection range α2 (S201), the control unit 45 determines whether the obstacle sensor 12 detected an object to be detected and its distance in the first detection range α1 or an object to be detected and its distance in the second detection range α2 (S202).

[0051] When the control unit 45 determines that an object to be detected and its distance have been detected in the second detection range α2 (S202 "second"), it does not drive the drive motors 43 of each drive wheel 32, maintaining the stopped state of the stationary automated guided vehicle 30 or stopping the moving automated guided vehicle 30 (S204). The control unit 45 displays an error message on the display unit 41 indicating that the USB memory M inserted into the USB interface 13 has been detected (S205), and generates a notification sound with the buzzer 42 (S206).

[0052] This allows the user to hear an alert sound or see an error message displayed on the display unit 41 when the automated guided vehicle 30 has stopped, remove the USB memory M from the USB interface 13, and restart the automated guided vehicle 30.

[0053] Furthermore, when the control unit 45 determines that an object to be detected and its distance have been detected within the first detection range α1 (S202 "first"), it maintains the stopped state of the stationary automated guided vehicle 30 or stops the moving automated guided vehicle 30 (S207). The control unit 45 displays an error message indicating that an obstacle has been detected on the display unit 41 (S208) and generates a notification sound with the buzzer 42 (S209).

[0054] As a result, when the user hears the notification sound, they can see the error message displayed on the display unit 41 while the automated guided vehicle 30 is stopped, recognize that there is an obstacle rather than the USB memory M being forgotten, remove the obstacle, and then restart the automated guided vehicle 30.

[0055] As shown in Figures 9 and 10, the obstacle sensor 12 and USB interface 13 may be installed in a portion 30D that is recessed by a predetermined amount in the direction opposite to the forward direction of travel of the automated guided vehicle 30, from the flat portion 30C of the front part of the main body 30A of the automated guided vehicle 30. This predetermined amount is such that the USB memory M connected to the USB interface 13 does not protrude forward from the main body 30A in the direction of travel, and fits within the area from portion 30D to the flat portion 30C. In this case, it is assumed that when connecting to the USB interface 13, a USB memory M that fits within the area from portion 30D to the flat portion 30C is used. With this configuration, the second detection range α2 can be set to an area that does not protrude forward from the main body 30A in the direction of travel, and the first detection range α1 can be set to an area in front of the main body 30A in the direction of travel, so that the control unit 45 can more accurately determine whether the detected object is an obstacle or a USB memory M. <Modified Form 2> In Modified Form 2, when the obstacle sensor 12 detects an object, the control unit 45 determines whether the detected object is an obstacle or a USB memory M, depending on whether the automated guided vehicle 30 is stopped or in motion. Figure 11 shows the control procedure by the control unit 45 in this case. In this Modified Form 2, the obstacle sensor 12 only needs to detect the object; it does not need to detect the distance to the object, etc.

[0056] The control unit 45 constantly determines whether the automated guided vehicle 30 is stopped or moving based on the drive control status of each drive motor 43 (S301). When the control unit 45 determines that the automated guided vehicle 30 is stopped (S301 "Stopped"), and determines that an object has been detected by the obstacle sensor 12 (S302 "Yes"), it does not drive the drive motors 43 of each drive wheel 32, maintaining the stopped state of the automated guided vehicle 30 (S303), and determines that the USB memory M attached to the USB interface 13 has been detected (S304). The control unit 45 displays an error message indicating that the USB memory M has been detected on the display unit 41 (S305), and generates a notification sound with the buzzer 42 (S306).

[0057] On the other hand, when the control unit 45 determines that the automated guided vehicle 30 is stopped (S301 "Stop"), when it determines that no object has been detected by the obstacle sensor 12 (S302 "No"), or when a start command is input to the operation unit 46 (S307 "Yes"), it drives the drive motors 43 of each drive wheel 32 to start the automated guided vehicle 30 moving (S308). The control unit 45 keeps the automated guided vehicle 30 stopped moving until a start command is input (S307 "No").

[0058] Subsequently, when the control unit 45 determines that the automated guided vehicle 30 is in a driving state (S309 "Yes"), and determines that an object has been detected by the obstacle sensor 12 (S310 "Yes"), it stops the driving motors 43 of each drive wheel 32, stops the automated guided vehicle 30 (S311), and determines that an obstacle has been detected (S312). The control unit 45 displays an error message indicating that an obstacle has been detected on the display unit 41 (S313) and generates a notification sound with the buzzer 42 (S314).

[0059] Furthermore, if the control unit 45 stops the unmanned transport vehicle 30, which has resumed travel based on the above start instruction, due to any reason (S309 "No"), the process ends. Also, in S310, if the control unit 45 does not determine that an object has been detected by the obstacle sensor 12 (S310 "No"), the unmanned transport vehicle 30 is kept traveling.

[0060] According to each of the above embodiments, the presence or absence of an external device can be detected using the existing obstacle sensor 12 on the automated guided vehicle 30.

[0061] Furthermore, the configurations and processes of the above embodiments described with reference to Figures 1 to 11, and the processes of each modified form, are merely embodiments of the present invention and are not intended to limit the present invention to these configurations and processes.

Claims

1. An automated guided vehicle (AGV) that travels along a travel line laid on a road surface, comprising: an obstacle sensor that detects an object to be detected in the area in front of the AGV's body in the direction of travel of the AGV; a connection part disposed at a position on the AGV's body to which an external device is detachably connected, such that the connected external device is located within the area to be detected by the obstacle sensor; and a control unit that performs predetermined control when the obstacle sensor detects the object to be detected.

2. The unmanned transport vehicle according to claim 1, wherein the control unit, when the object to be detected is detected by the obstacle sensor, performs a control to notify the detection of the obstacle as a predetermined control.

3. The unmanned transport vehicle according to claim 1, wherein the control unit, when the object to be detected is detected by the obstacle sensor, performs a predetermined control to stop the unmanned transport vehicle.

4. The unmanned transport vehicle according to claim 1, wherein the obstacle sensor detects the distance between the obstacle sensor and the object to be detected, and the control unit determines the object to be detected as an obstacle when the distance between the obstacle sensor and the object to be detected is greater than a preset first threshold, and determines the object to be detected as an external device when the distance between the obstacle sensor and the object to be detected is less than or equal to the first threshold.

5. The unmanned transport vehicle according to claim 4, wherein when the obstacle sensor detects the object to be detected, if the distance between the obstacle sensor and the object to be detected is less than or equal to the first threshold, the control unit determines the object to be detected as an obstacle and performs a process to maintain the stop of the unmanned transport vehicle or to stop its movement, and if the distance between the obstacle sensor and the object to be detected is greater than the first threshold, the control unit does not perform a process to maintain the stop of the unmanned transport vehicle or to stop its movement.

6. The detection range of the obstacle sensor is divided into a first detection range for detecting the object to be detected in the area in front of the travel direction of the automated guided vehicle, and a second detection range for detecting the object to be detected in the area including the location of the connection part, excluding the first detection range, and the control unit notifies the detection of the obstacle when the object to be detected is detected by the obstacle sensor and enters the first detection range, and notifies the detection of the external device when the object to be detected is detected by the obstacle sensor and enters the second detection range, as described in claim 1.

7. The control unit determines the stopped state and the running state of the automated guided vehicle, and when the stopped state of the automated guided vehicle is being determined, determines that the external device has been detected if the object to be detected is detected by the obstacle sensor, and when the stopped state of the automated guided vehicle is being determined, the object to be detected is not detected by the obstacle sensor, and when the running state of the automated guided vehicle is subsequently determined, determines that the obstacle has been detected if the object to be detected is detected by the obstacle sensor, according to claim 1.

8. The automated guided vehicle according to claim 1, wherein the external device is a small memory that is detachably connected to the connection part, and the control unit reads and acquires a program or data from the small memory through the connection part.

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