JP7618367B2 - Obstacle detection device, automated guided vehicle, and obstacle detection program - Google Patents

Description

The present invention relates to an obstacle detection device for an automated guided vehicle, an automated guided vehicle equipped with the obstacle detection device, and an obstacle detection program.

Conventionally, automated guided vehicles that travel and handle cargo autonomously are known. One example of this type of automated guided vehicle that detects its own position using a light projector/receiver mounted on the vehicle body and multiple reflectors arranged at predetermined positions within a facility is the automated guided vehicle disclosed in Patent Document 1. This automated guided vehicle detects its own position by emitting a laser using the light projector/receiver and detecting the reflected laser light from the multiple reflectors. This automated guided vehicle also has a lifting means for raising and lowering the light projector/receiver, and can change the light projection height and light reception height by raising and lowering this lifting means. As a result, even if there is an obstacle that blocks the laser, this automated guided vehicle can raise the light projector/receiver and irradiate the laser to avoid the obstacle.

However, automated guided vehicles are sometimes moved manually for maintenance and other reasons. When this happens, the light emitter/receiver, which is located higher than the vehicle body, may collide with the upper frame of an entrance/exit within a facility. For example, Patent Document 2 discloses an automated guided vehicle equipped with an obstacle sensor to prevent collisions with obstacles. This automated guided vehicle is configured to detect obstacles using the obstacle sensor and to slow down and stop before colliding with the obstacle. However, the obstacle sensor disclosed in Patent Document 2 only detects obstacles to the vehicle body, loading equipment, and load of the automated guided vehicle, and does not take into account obstacles to the light emitter/receiver.

Japanese Patent Application Publication No. 08-161038 JP 2017-224136 A

The problem that the present invention aims to solve is to provide an obstacle detection device capable of detecting obstacles around a light emitter/receiver, an unmanned guided vehicle equipped with the obstacle detection device, and an obstacle detection program.

In order to solve the above problems, the obstacle detection device according to the present invention is an obstacle detection device for an automated guided vehicle, the automated guided vehicle comprising a light emitter/receiver having a lift member that can be raised and lowered, a height detection unit that detects the height of the lift member, an irradiation unit that irradiates a laser while rotating horizontally, and a light receiving unit that detects reflected light of the laser, and a first control unit. The first control unit has a position estimation unit that analyzes the reflected light to estimate the positions of multiple reflectors arranged at predetermined positions in the facility and estimates the position of the automated guided vehicle. The obstacle detection device comprises a second control unit. The second control unit has a detection area storage unit that pre-stores multiple obstacle detection areas for detecting obstacles around the light emitter/receiver, and an obstacle detection unit that analyzes the reflected light in any of the obstacle detection areas to detect obstacles around the light emitter/receiver in the horizontal direction. The multiple obstacle detection areas include obstacle detection areas that do not include the area in the horizontal direction of the lift member, and the obstacle detection unit switches the obstacle detection area based on the height of the lift member to prevent erroneous detection of the lift member or load as an obstacle.

The obstacle detection device is preferably configured such that the unmanned guided vehicle can be switched to traveling under manual operation by a user not riding in the unmanned guided vehicle, and the first control unit is configured to estimate the position of the unmanned guided vehicle using the position estimation unit when the unmanned guided vehicle is traveling under manual operation, and the second control unit detects obstacles using the obstacle detection unit when the unmanned guided vehicle is traveling under manual operation.

The obstacle detection device preferably further includes an automatic guided vehicle equipped with a light emitter/receiver lifting unit that raises and lowers the light emitter/receiver, and the obstacle detection unit further switches the obstacle detection area based on the height of the light emitter/receiver.

In order to solve the above problem, the automated guided vehicle according to the present invention includes a light emitter/receiver having a lift member that can be raised and lowered, a height detection unit that detects the height of the lift member, an irradiation unit that irradiates a laser while rotating horizontally, and a light receiving unit that detects reflected light of the laser, a first control unit, and an obstacle detection device. The first control unit has a position estimation unit that analyzes the reflected light to estimate the positions of multiple reflectors arranged at predetermined positions in the facility and estimates the position of the automated guided vehicle. The obstacle detection device has a second control unit, which has a detection area storage unit that pre-stores multiple obstacle detection areas for detecting obstacles around the light emitter/receiver, and an obstacle detection unit that analyzes the reflected light in any of the obstacle detection areas to detect obstacles around the light emitter/receiver in the horizontal direction, and the multiple obstacle detection areas include obstacle detection areas that do not include an area in the horizontal direction of the lift member. The obstacle detection unit switches the obstacle detection area based on the height of the lift member to prevent erroneous detection of the lift member or the load as an obstacle.

In order to solve the above problem, the obstacle detection program of the present invention is an obstacle detection program for an automated guided vehicle, the automated guided vehicle is equipped with a lift member that can be raised and lowered, a height detection unit that detects the height of the lift member, an emitter/receiver having an irradiation unit that irradiates a laser while rotating horizontally, and a light receiving unit that detects reflected light of the laser, and a computer, and is configured so that the computer analyzes the reflected light to estimate the position of a reflector placed at a predetermined position in the facility and estimate the position of the automated guided vehicle. The obstacle detection program causes the computer to operate as the second control unit.

The obstacle detection device according to the present invention and an automated guided vehicle equipped with the obstacle detection device can detect obstacles around the light emitter/receiver.

1 is a side view showing an automated guided vehicle according to a first embodiment of the present invention; FIG. 2 is a perspective view showing autonomous driving of the automated guided vehicle shown in FIG. 1 . FIG. 2 is a schematic diagram showing how the automated guided vehicle shown in FIG. 1 travels under manual operation. FIG. 2 is a functional block diagram of the obstacle detection device. FIG. 1A is a schematic side view showing the height of each pattern of the obstacle detection device, and FIG. 1B is a schematic plan view showing the obstacle detection area for each pattern. 1A is a table showing an example of setting values for the obstacle detection area, and FIG. 1B is a schematic plan view showing the automatic guided vehicle and the obstacle detection area. 11 is a schematic side view showing an operation of the obstacle detection unit switching the obstacle detection area based on a predetermined height of the lift member. FIG. 1A is a schematic side view showing the operation of the obstacle detection unit switching the obstacle detection area for each height of the lift member, and FIG. 1B is a schematic plan view showing the obstacle detection area for each pattern. 11 is a table showing a judgment formula for switching an obstacle detection area and area patterns corresponding to the judgment results.

First Embodiment
Hereinafter, a first embodiment of an obstacle detection device and an unmanned guided vehicle equipped with the obstacle detection device of the present invention will be described with reference to the attached drawings. In the drawings, the arrows X, Y, and Z indicate the traveling direction of the vehicle.

<Automated Guided Vehicle>
First, the configuration of an automated guided vehicle 1 will be described. Fig. 1 is a side view showing an automated guided vehicle 1 according to one embodiment of the present invention. The automated guided vehicle 1 includes a vehicle body 10, wheels 11, a drive unit 12, a mast 13, a fork 14, a backrest 15, a lift bracket 16, a chain (not shown), a reel 17 (see Fig. 4), a hydraulic cylinder 18, a light emitter/receiver 19, an operation pendant 20 (see Fig. 3), and a computer 22.

The vehicle body 10 is mounted on the wheels 11, and the drive unit 12 is mounted inside the vehicle body 10. The drive unit 12 is configured to rotate the wheels 11 (drive wheels), turn the wheels 11, and stop the rotation of the wheels 11.

Although not described in detail in this specification, the automated guided vehicle 1 is also equipped with an obstacle sensor to prevent the vehicle body 10 from colliding with obstacles on the road while traveling.

The mast 13 has an outer mast 13a and an inner mast 13b, and is located at the rear of the vehicle body 10. The inner mast 13b is configured to be able to move up and down along the outer mast 13a. The fork 14 and the backrest 15 are connected to a lift bracket 16.

One end of the chain is connected to the outer mast 13a, and the other end of the chain is connected to the lift bracket 16 via the reel 17. When the hydraulic cylinder 18 expands and contracts, the inner mast 13b rises and lowers along the outer mast 13a, and the lift bracket 16 rises and lowers. The reel 17 is configured to rotate by the amount that the hydraulic cylinder 18 expands and contracts.

The inner mast 13b, the fork 14, the backrest 15 and the lift bracket 16 correspond to the "lift member" of the present invention. The automated guided vehicle of the present invention may be equipped with other attachments. For example, the automated guided vehicle 1 may be an automated forklift capable of loading and unloading in three directions by shifting and rotating. In this case, the L-shaped head and the like are also included in the lift member. In other words, the lift member of the present invention is a member that is raised and lowered by a lifting device such as a hydraulic cylinder 18.

The light emitter/receiver 19 has an irradiation unit and a light receiving unit. As shown in FIG. 2, the irradiation unit emits a laser L while rotating horizontally, and the light receiving unit detects the reflected light of the laser L from multiple reflectors R arranged at predetermined positions within the facility.

The operation pendant 20 has a cord 20a and switches, buttons, etc. for a user U who is not on the automated guided vehicle 1 to operate the vehicle, and is configured to be able to communicate with the computer 22 by wire, as shown in FIG. 3. Note that the operation pendant 20 is merely an example, and the components for the user U to manually operate the automated guided vehicle 1 are not limited to this, and the automated guided vehicle 1 may be configured to be operated by wireless operation. In this embodiment, during manual operation, the maximum speed in normal driving mode when moving forward of the automated guided vehicle 1 is set to 2.52 [km/h], and the maximum speed in normal driving mode when moving backward is set to 1.08 [km/h]. Furthermore, the maximum speed of the automated guided vehicle 1 in the deceleration driving mode is set to 0.8 [km/h] for both forward and backward movements.

Figure 4 is a functional block diagram of the automated guided vehicle 1. As shown in Figure 4, the automated guided vehicle 1 further includes a height detection unit 21.

The height detection unit 21 is configured to detect the height of the lift member using known technology. For example, the automated guided vehicle 1 may further include a reel encoder that detects the number of rotations of the reel 17, and the height estimation unit may detect the height of the lift member based on the number of rotations of the reel 17 received from the reel encoder. Note that the configuration in which the height detection unit 21 detects the height of the lift member is not limited to this.

The computer 22 has a storage device, a memory, and an arithmetic unit, and is housed in the vehicle body 10. The storage device stores an operating system (OS), a position estimation program, and an obstacle detection program. The position estimation program causes the computer 22 to operate as the first control unit 23 of the present invention, and the obstacle detection program causes the computer 22 to operate as the second control unit 30 of the present invention.

The first control unit 23 has a driving control unit 23a, a first memory unit 23b, and a position estimation unit 23c.

The driving control unit 23a controls the drive unit 12 to rotate and stop the wheels 11.

The first memory unit 23b stores the positions of the reflectors R placed within the facility and the travel route of the automated guided vehicle 1.

The position estimation unit 23c analyzes the reflected light of the laser L from multiple reflectors R to estimate the position of the automated guided vehicle 1. The estimated position of the automated guided vehicle 1 is transmitted to the travel control unit 23a.

Based on the driving route and the received position of the automated guided vehicle 1, the driving control unit 23a autonomously drives the automated guided vehicle 1 along the driving route, as shown in FIG. 2.

Obstacle detection device
Next, the configuration of the obstacle detection device 3 will be described. The obstacle detection device 3 includes a second control unit 30. In this embodiment, the first and second control units 23, 30 are configured from the same computer 22, but the first and second control units 23, 30 may be configured from separate computers 22. The second control unit 30 includes a second storage unit 30a and an obstacle detection unit 30b. The second storage unit 30a corresponds to the "detection area storage unit" of the present invention. In this embodiment, the obstacle detection device 3 is set to operate only during manual operation.

The second memory unit 30a stores a plurality of obstacle detection areas E for detecting objects around the light emitter/receiver 19 as obstacles O. FIG. 5 is a schematic plan view showing the obstacle detection areas E. As shown in FIG. 5, the plurality of obstacle detection areas E include an obstacle detection area EA of pattern A that includes an area in the direction of the mast 13, and an obstacle detection area EB of pattern B that does not include an area in the direction of the mast 13. Note that in this specification, the obstacle detection areas EA and EB are configured in a rectangular shape, but this is merely an example, and the shape of the obstacle detection area E is not limited to this.

Figure 6A is a table showing an example of the settings of the obstacle detection area E. Rows A and B in Figure 6A show the setting values for pattern A and pattern B, respectively. Figure 6B is a schematic plan view showing the automated guided vehicle 1 and obstacle detection area E, showing the parts corresponding to X1, X2, Y1, and Y2 in the table. As shown in Figure 6B, X1 indicates the rearward length from the center of the light emitter/receiver 19, and X2 indicates the forward length from the center of the light emitter/receiver. Additionally, Y1 indicates the leftward length from the center of the light emitter/receiver 19, and Y2 indicates the rightward length from the center of the light emitter/receiver 19.

As shown in FIG. 6A, the obstacle detection area E may be set for each vehicle model. As shown in FIG. 5, in this embodiment, the obstacle detection areas EA and EB of the A and B patterns each have a deceleration area E1 and a stop area E2. The deceleration area E1 is an area set in the normal driving mode, and the stop area E2 is an area set in the deceleration driving mode. The lengths of X1 and X2 in the deceleration area E1 are different because when an obstacle O is detected in the normal driving mode, deceleration is first required, and the distance until deceleration is completed differs depending on the maximum speed, and the maximum speed differs depending on whether the vehicle is traveling forward or backward. In addition, the stop area E2 is an area used in the deceleration driving mode, so it is set narrower than the deceleration area E1.

The obstacle detection unit 30b switches the obstacle detection area E between pattern A and pattern B based on the predetermined height of the lift member. Figure 7 shows the operation of the obstacle detection unit 30b to switch the obstacle detection area E between pattern A and pattern B based on the predetermined height H of the lift member. In Figure 7, the height of the forks 14 is shown as the height of the lift members, but this is because the height detection unit 21 detects the height of the lift members based on the number of revolutions of the reel 17, and because the number of revolutions of the reel 17 and the height of the forks 14 are linked, the number of revolutions of the reel 17 (i.e., the height of the lift members) is shown as the height of the forks 14.

The obstacle detection unit 30b analyzes the reflected light of the laser L from objects other than the reflector R, such as pillars and walls, and detects the angle of the reflected light and the horizontal distance from the center of the light emitter/receiver 19 to the surrounding objects. When the obstacle detection unit 30b determines that the surrounding objects are located within the obstacle detection area E, it determines that there is an obstacle O around the light emitter/receiver 19 and sends an obstacle detection signal to the driving control unit 23a, and switches the obstacle detection area E from the deceleration area E1 to the stop area E2.

When the driving control unit 23a receives an obstacle detection signal during normal driving mode during manual operation, it changes the driving mode of the automated guided vehicle 1 to a deceleration driving mode. That is, in this embodiment, the driving control unit 23a decelerates the maximum speed of the automated guided vehicle 1 from 2.52 [km/h] or 1.08 [km/h] to 0.8 [km/h].

Furthermore, when the obstacle detection unit 30b analyzes the reflected light of the laser L and determines that a surrounding object is located within the obstacle detection area E, it determines that an obstacle O is present around the light emitter/receiver 19 and sends an obstacle detection signal to the driving control unit 23a. When the driving control unit 23a receives an obstacle detection signal during deceleration driving mode during manual operation, it stops the driving of the automatic guided vehicle 1. In this way, the obstacle detection device 3 prevents the light emitter/receiver 19 from colliding with the obstacle O.

In addition, when the forks 14 (lift members) are at or above a certain height H, the obstacle detection unit 30b switches the obstacle detection area E from pattern A to pattern B, thereby preventing the lift members including the inner mast 13b from being erroneously detected as an obstacle O. This allows the obstacle detection device 3 to properly detect the obstacle O.

In this way, the obstacle detection device 3 can reduce the cost of installing a new obstacle detection sensor by using the light emitter/receiver 19 as an obstacle detection sensor.

For example, if the automated guided vehicle 1 is moved off the driving route (lined out) by manual operation, it is difficult to quickly detect its own position even if it is returned to the driving route (lined in), and it cannot smoothly return to automatic driving. However, by continuing to detect its own position by the position estimation unit 23c even when it is operated manually, it can smoothly return to automatic driving. In other words, according to the configuration of this embodiment, when the automated guided vehicle 1 is driven by manual operation, the laser L is irradiated by the light emitter/receiver 19, while the obstacle detection unit 30b detects an obstacle O and the position estimation unit 23c constantly estimates its own position, so that it can safely drive manually and smoothly return from manual operation to automatic driving.

Second Embodiment
Next, a second embodiment of the obstacle detection device and the automatic guided vehicle including the obstacle detection device of the present invention will be described. Note that the description of the same configuration as the first embodiment may be omitted.

<Automated Guided Vehicle>
The automated guided vehicle 1 further includes a light emitter/receiver lifting unit (not shown) that lifts and lowers the light emitter/receiver 19. Other configurations of the automated guided vehicle 1 are similar to those of the automated guided vehicle 1 of the first embodiment. Therefore, a description of the other configurations will be omitted.

The light emitter/receiver lifting unit is configured using known technology and raises and lowers the light emitter/receiver 19. As a result, even if the heights of multiple reflectors R arranged in a facility are different, the automated guided vehicle 1 can raise and lower the light emitter/receiver 19 to appropriately irradiate each reflector R with a laser L. The light emitter/receiver lifting unit may be configured, for example, as a telescopic device, but this is merely an example and the configuration of the light emitter/receiver lifting unit is not limited to this. As shown in FIG. 8, the light emitter/receiver lifting unit of this embodiment is configured to change the height of the light emitter/receiver 19 at three levels: a lower limit position, an intermediate position, and an upper limit position. However, this is also merely an example, and the light emitter/receiver lifting unit may position the light emitter/receiver 19 at further heights or at four or more levels.

Obstacle detection device
The obstacle detection device 3 has the same physical configuration as that of the first embodiment, so a description of the configuration that is the same as that of the first embodiment will be omitted.

The obstacle detection unit 30b switches the obstacle detection area E between pattern A and pattern B based on the height of the light emitter/receiver 19 and the height of the lift member. Figure 8 shows the operation of the obstacle detection unit 30b to switch the obstacle detection area E between pattern A and pattern B based on the height of the light emitter/receiver 19 and the lift member. As shown in Figure 8, first to third reference heights are set for the lower limit position, middle position, and upper limit position of the light emitter/receiver 19, respectively.

Figure 9 shows in a table the judgment formula used when switching the obstacle detection area E and the area pattern corresponding to the judgment result. As shown in Figure 9, the obstacle detection unit 30b judges whether the height of the lift member (fork height) is equal to or greater than the corresponding reference height for each height of the light emitter/receiver 19, and switches the pattern of the obstacle detection area E based on the judgment result.

The obstacle detection unit 30b detects an obstacle O around the light emitter/receiver 19 by referring to the switched obstacle detection area E and the positions of objects around the light emitter/receiver 19, and when an obstacle O is detected, it transmits an obstacle detection signal to the travel control unit 23a in the same manner as in the first embodiment. The travel control unit 23a decelerates or stops the automated guided vehicle 1 in the same manner as in the first embodiment.

With the above configuration, when the automated guided vehicle 1 is manually operated, it can detect its own position by appropriately irradiating the laser L to each reflector R, while appropriately preventing the light emitter/receiver 19 from colliding with the obstacle O by avoiding detecting the lift member as an obstacle O.

Although the first and second embodiments of the present invention have been described above, the obstacle detection device, the automated guided vehicle equipped with the obstacle detection device, and the obstacle detection program of the present invention are not limited to the above-mentioned embodiments. The obstacle detection device, the automated guided vehicle, and the obstacle detection program of the present invention may be implemented, for example, by the following modified examples.

<Modification>
The obstacle detection device 3 may also operate during autonomous driving of the automated guided vehicle 1. In this case, it is preferable that the area of the obstacle detection area E differs depending on the maximum speed setting of the automated guided vehicle 1 (for example, the setting for each area in a facility). In addition, when operating during autonomous driving, the obstacle detection unit 30b may further switch the pattern of the obstacle detection area E based on the height of a load being transported by the automated guided vehicle 1. In this case, the obstacle detection device 3 may further include a load height detection unit that detects the height of the load.

- In the case of pattern B, the length X1 of the obstacle detection area E in the direction of the lift member does not have to be 0. However, even in this case, X1 is set to a length that does not cause the obstacle detection unit 30b to erroneously detect the lift member as an obstacle O.

The obstacle detection device 3 may further include an alarm device and be configured to issue an alarm when an obstacle O is detected.

1 Automatic guided vehicle 10 Vehicle body 11 Wheel 12 Drive unit 13 Mast 13a Outer mast 13b Inner mast 14 Fork 15 Backrest 16 Lift bracket 17 Reel 18 Hydraulic cylinder 19 Light emitter/receiver 20 Operation pendant 21 Height detection unit 22 Computer 23 First control unit 23a Travel control unit 23b First memory unit 23c Position estimation unit 3 Obstacle detection device 30 Second control unit 30a Second memory unit (detection area memory unit)
30b Obstacle detection unit L Laser O Obstacle R Reflector U User E Obstacle detection area E1 Deceleration area E2 Stop area

Claims (5)

An obstacle detection device for an automated guided vehicle, comprising:
The automated guided vehicle is
A lift member that can be raised and lowered;
A height detection unit that detects the height of the lift member;
a light projector/receiver having an irradiation unit that irradiates a laser while rotating in a horizontal direction and a light receiving unit that detects reflected light of the laser;
A first control unit,
The first control unit is
a position estimation unit that estimates positions of a plurality of reflectors arranged at predetermined positions in a facility by analyzing the reflected light, and estimates a position of the automatic guided vehicle;
The obstacle detection device includes a second control unit,
The second control unit is
a detection area storage unit that stores in advance a plurality of obstacle detection areas for detecting obstacles around the light emitter/receiver;
an obstacle detection unit that detects the obstacle around the light emitter/receiver in a horizontal direction by analyzing the reflected light in any one of the obstacle detection areas,
The obstacle detection areas include an obstacle detection area that does not include an area in a horizontal direction of the lift member,
The obstacle detection unit switches the obstacle detection area based on the height of the lift member to prevent erroneous detection of the lift member or the load as the obstacle. The automated guided vehicle can be switched to traveling by manual operation of a user who is not riding in the automated guided vehicle,
the first control unit is configured to estimate a position of the automatic guided vehicle by the position estimation unit when the automatic guided vehicle travels by the manual operation,
The obstacle detection device according to claim 1 , wherein the second control unit detects the obstacle by the obstacle detection unit when the automatic guided vehicle travels by the manual operation. The automated guided vehicle further includes a light emitter/receiver lifting unit that lifts and lowers the light emitter/receiver,
3. The obstacle detection device according to claim 1, wherein the obstacle detection unit further switches the obstacle detection area based on a height of the light emitter/receiver. An automated guided vehicle,
A lift member that can be raised and lowered;
A height detection unit that detects the height of the lift member;
a light projector/receiver having an irradiation unit that irradiates a laser while rotating in a horizontal direction and a light receiving unit that detects reflected light of the laser;
A first control unit;
An obstacle detection device,
The first control unit is
a position estimation unit that estimates positions of a plurality of reflectors arranged at predetermined positions in a facility by analyzing the reflected light, and estimates a position of the automatic guided vehicle;
The obstacle detection device includes:
A second control unit is provided.
The second control unit is
a detection area storage unit that stores in advance a plurality of obstacle detection areas for detecting the obstacles around the light emitter/receiver;
an obstacle detection unit that detects obstacles around the light emitter/receiver in a horizontal direction by analyzing the reflected light in any one of the obstacle detection areas,
The obstacle detection areas include an obstacle detection area that does not include an area in a horizontal direction of the lift member,
The obstacle detection unit of the automated guided vehicle switches the obstacle detection area based on the height of the lift member to prevent erroneous detection of the lift member or a load as the obstacle. An obstacle detection program for an automated guided vehicle, comprising:
The automated guided vehicle is
A lift member that can be raised and lowered;
A height detection unit that detects the height of the lift member;
a light projector/receiver having an irradiation unit that irradiates a laser while rotating in a horizontal direction and a light receiving unit that detects reflected light of the laser;
A computer,
The computer is configured to analyze the reflected light to estimate a position of a reflector disposed at a predetermined position in a facility and estimate a position of the automated guided vehicle,
The obstacle detection program includes:
An obstacle detection program that causes the computer to operate as the second control unit according to claim 1.

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