Automated guided vehicle travel system and automated guided vehicle

Abstract

An automated guided vehicle travel system Sy comprises a travel line 10 that is laid on a road surface and is to be detected by a line sensor 11, a magnetic body mark 20 that is superimposed on the travel line 10, and an automated guided vehicle 30 that travels along the travel line 10. The automated guided vehicle 30 comprises a line sensor 11 that optically detects the position of the travel line 10, a magnetic sensor 12 that detects the magnetic body mark 20, and a control unit 45 that controls the travel direction of the automated guided vehicle 30 in accordance with the position of the travel line 10 as detected by the line sensor 11 and performs drive control of the automated guided vehicle 30 on the basis of the magnetic body mark 20 as detected by the magnetic sensor 12.

Description

Automated Guided Vehicle Travel System and Automated Guided Vehicle

[0001] The present invention relates to an automated guided vehicle travel system and an automated guided vehicle that detect a travel line laid on a road surface and cause the automated guided vehicle to travel along the travel line, and particularly to a technique for detecting a magnetic mark together with the travel line and controlling the automated guided vehicle.

[0002] As an automated guided vehicle, there is one that optically or magnetically detects a travel line laid on a road surface, causes the automated guided vehicle to travel along the travel line, and also detects a magnetic mark separately provided on the road surface, and controls the automated guided vehicle according to the detection of the magnetic mark.

[0003] For example, in the automated guided vehicle described in Patent Document 1, a track line (travel line) is provided on the floor, a plurality of magnetic markers are sequentially arranged along the track line, and while detecting the track line with a track line detection sensor of the automated guided vehicle, the automated guided vehicle is caused to travel along the track line. Also, each time approaching each magnetic marker sequentially, the approaching magnetic marker is detected by either one of two marker detection sensors provided on both sides of the automated guided vehicle and counted up, and the travel control of the automated guided vehicle is performed according to a command corresponding to a predetermined count-up number. Here, the track line detection sensor is a sensor that analogously detects the magnetic force of a track line composed of magnetic field lines of the N pole.

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

[0005] In the technology described in Patent Document 1, a track line (travel line) is provided on the floor, and the travel direction is determined according to the magnetic force detected from the track line by a track line detection sensor. Therefore, it is necessary to ensure that the detection of the magnetic force of the track line by the track line detection sensor does not interfere with multiple magnetic markers. For this reason, in the technology described in Patent Document 1, multiple magnetic markers are placed spaced apart from the track line on both sides (outside), and a track line detection sensor is placed near the center in the width direction (direction perpendicular to the travel direction) of the main body of the automated guided vehicle (AGV), and the track line detection sensor detects the track line passing through the center of the main body of the AGV. Then, two marker detection sensors are placed on both sides of the AGV, and each marker detection sensor detects the respective magnetic markers placed on both sides of the track line.

[0006] Therefore, the automated guided vehicle (AGV) travels so that the track line passes through the center of the AGV's body and near each magnetic marker. As a result, the AGV's wheels do not run over the track line or the magnetic markers, preventing contamination or damage to the track line or magnetic markers.

[0007] However, in a configuration where multiple magnetic markers are placed spaced apart from the track line on both sides, the placement positions of the track line and each magnetic marker in the width direction become separated, and the size of the automated guided vehicle (AGV) in which the track line detection sensor and marker detection sensor are placed opposite these becomes larger.

[0008] This invention has been made in view of the above circumstances, and aims to enable the wheels of an automated guided vehicle to not run over the running lines and multiple magnetic marks, to arrange the running lines and each magnetic mark within a relatively small area, and to enable the miniaturization of the automated guided vehicle.

[0009] An automated guided vehicle (AGV) travel system according to one aspect of the present invention comprises a travel line laid on a road surface and subject to detection by an optical sensor, a magnetic mark placed on top of the travel line, and an AGV that travels along the travel line, wherein the AGV includes an optical sensor that optically detects the position of the travel line, a magnetic sensor that detects the magnetic mark, and a control unit that controls the travel direction of the AGV according to the position of the travel line detected by the optical sensor and drives the AGV based on the magnetic mark detected by the magnetic sensor.

[0010] Furthermore, 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 optical sensor that optically detects the position of the travel line laid on the road surface; a magnetic sensor that detects a magnetic mark placed on top of the travel line; 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 optical sensor and controls the automated guided vehicle based on the magnetic mark detected by the magnetic sensor.

[0011] According to the present invention, the wheels of the automated guided vehicle will not run over the running lines and multiple magnetic marks, the running lines and each magnetic mark can be arranged within a relatively small area, and the automated guided vehicle can be made smaller.

[0012] This is a schematic diagram showing an automated guided vehicle (AGV) driving system according to one embodiment of the present invention. This is a plan view showing an enlarged view of the driving line and magnetic mark in the AGV driving system of this embodiment. (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. (A) is a diagram showing the position of the driving line and magnetic mark when the direction of the AGV is changed to the right, and (B) is a diagram showing the position of the driving line and magnetic mark when the direction of the AGV is changed to the left.

[0013] 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.

[0014] Figure 1 is a schematic diagram showing an automated guided vehicle (AGV) travel system according to one embodiment of the present invention. The AGV travel system Sy shown in Figure 1 comprises a travel line 10 laid on the road surface, magnetic marks 20 placed on top of the travel line 10, and an AGV 30 that travels along the travel line 10.

[0015] The automated guided vehicle 30 is equipped with a line sensor 11 that is positioned facing the road surface and detects the travel line 10 and its position, and a magnetic sensor 12 that detects magnetic mark 20. The line sensor 11 is, for example, a CIS (Contact Image Sensor) or a CCD (Charge Coupled Device). In this embodiment, an example in which the line sensor 11 is a CCD is described. The line sensor 11 is an example of an optical sensor in the claims. The line sensor 11 is positioned in the width direction of the travel line 10 (in a direction perpendicular to the length direction in which the travel line 10 extends, and perpendicular to the travel direction of the automated guided vehicle 30) to a predetermined length that is greater than the width of the travel line 10, and is positioned to read the entire area of ​​the travel line 10 in its width direction and to read the ground on both sides of the travel line 10 in that width direction. The magnetic sensor 12 is, for example, a known sensor that detects the magnitude and direction of the magnetic field emitted by a magnet.

[0016] In the main body 30A of the automated guided vehicle 30, the line sensor 11 and the magnetic sensor 12 are arranged in a predetermined area within the central part of the main body 30A of the automated guided vehicle 30 in the width direction (direction perpendicular to the direction of travel), and are positioned side by side along the travel direction A of the automated guided vehicle 30. Here, the line sensor 11 is positioned in front of the magnetic sensor 12 in the direction of travel of the automated guided vehicle 30, but the order in which the line sensor 11 and the magnetic sensor 12 are arranged may be reversed.

[0017] In the automated guided vehicle (AGV) 30, steering control is performed according to the position of the travel line 10 detected by the line sensor 11, and the control unit 45 (Figure 4) controls the AGV 30 based on the magnetic marks 20 detected by the magnetic sensor 12. For example, under the control of the control unit 45, the AGV 30 starts moving from a preset starting position, and as the magnetic sensor 12 sequentially detects each magnetic mark 20, the number of detected magnetic marks 20 is counted each time a magnetic mark 20 is detected, and control such as moving and stopping the AGV 30 is performed according to the counted number of magnetic marks 20.

[0018] Figure 2 is a magnified view showing the driving line 10, magnetic mark 20, etc. As shown in Figure 2, the driving line 10 is a non-magnetic material (for example, vinyl tape) in the form of a strip and sheet of uniform width, and is preferably black or gray. The color or density of the driving line 10 is set to a predetermined value that has a sufficient difference from the color or density of the road surface.

[0019] The magnetic mark 20 is a sheet-like magnetic material placed on top of the running line 10. The color or density of the magnetic mark 20 may be matched to or approximate the color or density of the running line 10.

[0020] 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 30. Inside the bottom of the automated guided vehicle 30, four drive wheels 32 are provided spaced apart from each other in a direction perpendicular to the direction of travel of the automated guided vehicle 30, and the axes of each drive wheel 32 are aligned in a straight line. Under the control of the control unit 45 (Figure 4), which will be described later, each drive wheel 32 is rotated by its respective drive motor, causing the automated guided vehicle 30 to move and each caster 31 to rotate in response.

[0021] Each drive wheel 32 is positioned outward in the width direction of the main body of the automated guided vehicle 30 from the positions where the line sensor 11 and magnetic sensor 12 are located on the main body of the automated guided vehicle 30. Furthermore, the four casters 31 and the four drive wheels 32 are distributed to the left and right from the center of the width direction of the main body 30A of the automated guided vehicle 30, and are not positioned in the central area of ​​the width direction of the main body 30A.

[0022] Here, with each drive wheel 32 in contact with the floor, the control unit 45 controls the drive motor of each drive wheel 32 individually, adjusting the rotation speed of the drive wheels 32 and switching the rotation direction of the drive wheels 32, causing the automated guided vehicle 30 to move and steering control of the automated guided vehicle 30 to be performed. As a result, the direction of travel of the automated guided vehicle 30 is changed, and each caster 31 rotates accordingly and changes its orientation.

[0023] The rotation control of each drive wheel 32 when the automated guided vehicle 30 is in motion will be explained. Figures 3(A) to 3(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 3 are for the example shown in Figure 3. The rotation control of each drive wheel 32 shown below is performed by the control unit 45.

[0024] As shown in Figure 3(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).

[0025] As shown in Figure 3(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).

[0026] As shown in Figure 3(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.

[0027] As shown in Figure 3(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.

[0028] 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.

[0029] Although four drive wheels 32 are shown as an example here, it is also possible to configure the system with two drive wheels 32, distributed to the left and right from the center of the width direction of the main body 30A of the automated guided vehicle 30, and to control the rotation speed and rotation direction of the left and right drive wheels 32 respectively, thereby driving the automated guided vehicle 30 as shown in Figures 3(A) to (D).

[0030] Figure 4 is a block diagram showing the control system of the automated guided vehicle 30. As shown in Figure 4, the automated guided vehicle 30 includes a line sensor 11, a magnetic sensor 12, each drive motor 42 that rotates each drive wheel 32, a memory unit 44, and a control unit 45.

[0031] 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 reads and detects the position of the travel line 10 in the longitudinal direction of the line sensor 11 (width direction of the main body 30A).

[0032] Furthermore, as shown in Figure 1, the magnetic sensor 12 is positioned in the center of the main body 30A of the automated guided vehicle 30 and is aligned with the line sensor 11 along the travel direction A of the automated guided vehicle 30. The magnetic sensor 12 magnetically detects the magnetic mark 20 that is placed on top of the travel line 10.

[0033] The memory unit 44 is, for example, a non-volatile memory, and for each number of magnetic marks 20 detected by the magnetic sensor 12, control information for the automated guided vehicle 30 is stored in association with this number.

[0034] 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.

[0035] Furthermore, the running line 10 corresponds to the running line in the claims, the magnetic mark 20 corresponds to the magnetic mark in the claims, the line sensor 11 corresponds to the optical sensor in the claims, the magnetic sensor 12 corresponds to the magnetic sensor in the claims, the control unit 45 corresponds to the control unit in the claims, and each caster 31 and each drive wheel 32 corresponds to the wheel in the claims.

[0036] For example, the control unit 45 controls the drive motor 42 of each drive wheel 32 to maintain a state in which the image read by the line sensor 11 of the travel line 10 is located in the central part of the width direction (longitudinal direction) of the travel line 10. If the image read by the line sensor 11 of the travel line 10 is no longer located in the central part of the width direction of the travel line 10, the control unit 45 immediately controls the drive motor 42 of each drive wheel 32 to change the orientation of the automated guided vehicle 30 toward the central position in the width direction of the travel line 10. As a result, the control unit 45 controls the operation of the automated guided vehicle 30 to travel along the travel line 10.

[0037] Since the magnetic mark 20 is positioned on the travel line 10, the above control causes the automated guided vehicle 30 to travel along the travel line 10 with the central position of the main body 30A of the automated guided vehicle 30 passing over the travel line 10 and the magnetic mark 20.

[0038] When the automated guided vehicle (AGV) 30 is traveling along the travel line 10, a magnetic sensor 12 positioned in the center of the width direction of the main body 30A of the AGV 30 sequentially detects each magnetic mark 20 superimposed on the travel line 10 magnetically. The magnetic sensor 12 does not detect the non-magnetic travel line 10. After the control unit 45 starts the AGV 30 from a preset start position on the travel line 10, as each magnetic mark 20 is sequentially detected by the magnetic sensor 12, the control unit 45 counts the number of detected magnetic marks 20 each time a magnetic mark 20 is detected, and reads control information for the AGV 30 associated with this counted number of magnetic marks 20 (which magnetic mark 20 it is from the start position) from the storage unit 44. The control unit 45 controls the operation of the AGV 30 according to the contents indicated by this read control information. For example, the control unit 45 controls the drive motor 42 of each drive wheel 32 according to the determined control information, adjusting the rotational speed of the drive wheels 32 to move or stop the automated guided vehicle 30.

[0039] Here, as described above, the magnetic mark 20 is placed on top of the travel line 10, and the line sensor 11 and magnetic sensor 12 are arranged in the center of the main body 30A of the automated guided vehicle 30 and along the travel direction A of the automated guided vehicle 30. The line sensor 11 detects the travel line 10, and the magnetic sensor 12 detects the magnetic mark 20. In other words, in this embodiment, the travel line 10 is not made of magnetic material, and the configuration does not involve detecting the travel line 10 using a magnetic sensor based on magnetism. Therefore, even if the magnetic mark 20 is placed on top of the travel line 10, the following situations do not occur, such as when the magnetic sensor detects the travel line 10, the magnetic sensor also detects the magnetic mark 20, making it unclear whether the detected object is the travel line 10 or the magnetic mark 20. Furthermore, when the magnetic sensor detects the magnetic mark 20, the magnetic sensor also detects the travel line, which is made of magnetic material, making it unclear whether the detected object is the travel line 10 or the magnetic mark 20.

[0040] Therefore, as shown in Figures 5(A) and (B), steering control of the automated guided vehicle 30 is performed so that the central position of the main body 30A of the automated guided vehicle 30 substantially coincides with the position of the travel line 10 or the magnetic mark 20, so that the automated guided vehicle 30 travels along the travel line 10 and the magnetic mark 20, and the magnetic sensor 12 reliably detects the magnetic mark 20 superimposed on the travel line 10.

[0041] Further, the magnetic mark 20 is provided so as to overlap the travel line 10, the line sensor 11 and the magnetic sensor 12 are arranged side by side along the travel direction A of the unmanned carrier vehicle 30 at the center of the main body 30A of the unmanned carrier vehicle 30, and it is not necessary to arrange the magnetic mark 20 outside the width direction of the travel line 10. It becomes easy to arrange the four casters 31 and the four drive wheels 32 at the bottom of the unmanned carrier vehicle 30 at positions where they do not step on the travel line 10 during the travel of the unmanned carrier vehicle 30. For this reason, as long as the unmanned carrier vehicle 30 is traveling along the travel line 10, the situation where the drive wheels of the unmanned carrier vehicle step on the magnetic mark, which occurs when the magnetic mark is arranged outside the width direction of the travel line, does not occur, and the travel line 10 and particularly the magnetic mark 20 are prevented from being soiled or damaged.

[0042] Further, since a plurality of magnetic marks 20 are arranged so as to overlap the travel line 10, the travel line 10 and each magnetic mark 20 can be arranged in a relatively small area.

[0043] Further, the line sensor 11 and the magnetic sensor 12 can be arranged side by side along the travel direction A of the unmanned carrier vehicle 30 at the center in the width direction of the main body 30A of the unmanned carrier vehicle 30, and it is not necessary to arrange the line sensor 11 and the magnetic sensor 12 side by side in the width direction. Therefore, the size of the main body 30A of the unmanned carrier vehicle 30 in the width direction can be reduced, and the unmanned carrier vehicle 30 can be downsized.

[0044] Further, since the magnetic sensor 12 is arranged at the center of the main body 30A of the unmanned carrier vehicle 30, other components can be freely arranged in the spaces on both sides of the line sensor 11 of the main body 30A of the unmanned carrier vehicle 30, and the degree of freedom in the design of the unmanned carrier vehicle 30 is increased.

[0045] In the above embodiment, the control unit 45 controls the rotational speed and rotational direction of each of the multiple drive wheels 32 to move the automated guided vehicle 30 forward, backward, turn to the right, and turn to the left. However, the drive wheels and steering wheels may be provided separately, and the control unit 45 controls the rotational speed and rotational direction of the drive wheels to change the travel speed of the automated guided vehicle 30, and the control unit 45 switches between forward and reverse, and changes the direction of the steering wheels to change the direction of travel of the automated guided vehicle 30. In this case, the drive wheels and steering wheels are arranged to the left and right from the center in the width direction of the main body 30A of the automated guided vehicle 30, and are not arranged in the central area in the width direction of the main body 30A.

[0046] Furthermore, the configuration and processing of the above embodiment described with reference to Figures 1 to 5 are merely one embodiment of the present invention, and the present invention is not intended to be limited to such configuration and processing.

Claims

1. An automated guided vehicle (AGV) driving system comprising: a driving line laid on a road surface and subject to detection by an optical sensor; a magnetic mark placed on top of the driving line; and an AGV that travels along the driving line, wherein the AGV includes: an optical sensor that optically detects the position of the driving line; a magnetic sensor that detects the magnetic mark; and a control unit that controls the direction of travel of the AGV according to the position of the driving line detected by the optical sensor and drives the AGV based on the magnetic mark detected by the magnetic sensor.

2. The automated guided vehicle (AGV) travel system according to claim 1, wherein the optical sensor and the magnetic sensor are arranged in a predetermined area in the width direction of the AGV body, aligned along the travel direction of the AGV.

3. The automated guided vehicle (AGV) travel system according to claim 1, wherein the AGV has a plurality of wheels, and each wheel is positioned outward in the width direction of the main body of the AGV from the position where the optical sensor and the magnetic sensor are installed on the main body of the AGV.

4. The automated guided vehicle (AGV) travel system according to claim 1, wherein the optical sensor is arranged to have a length that allows it to read the entire area in the width direction of the travel line and to read the ground on both sides of the travel line in the width direction.

5. An automated guided vehicle (AGV) that travels along a travel line laid on a road surface, comprising: an optical sensor that optically detects the position of the travel line laid on the road surface; a magnetic sensor that detects a magnetic mark placed on top of the travel line; and a control unit that controls the travel direction of the AGV according to the position of the travel line detected by the optical sensor and drives the AGV based on the magnetic mark detected by the magnetic sensor.

6. The automated guided vehicle according to claim 4, wherein the optical sensor and the magnetic sensor are arranged in a predetermined area in the width direction of the main body of the automated guided vehicle, aligned along the direction of travel of the automated guided vehicle.

7. The automated guided vehicle according to claim 5, wherein the automated guided vehicle has a plurality of wheels, and each of the wheels is positioned outward in the width direction of the main body of the automated guided vehicle from the position where the optical sensor and the magnetic sensor are installed on the main body of the automated guided vehicle.

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