JP3149661B2 - Automatic guided vehicle position identification method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for identifying a position of an automatic guided vehicle, which can freely travel and judges a traveling environment by itself.

[0002]

2. Description of the Related Art In the past, most of AGVs used were of a type in which an electric track such as a reflective tape, a magnet tape, or a magnetic wire was adhered to a floor and used as a guide rail. This guide rail is sure AGV
However, when buried in the floor, it takes time and effort to perform the initial floor work and it is very difficult to change the route. In addition, since the traveling of the vehicle is limited to the guide rail attachment area, the degree of freedom of traveling is limited. In addition, if the vehicle deviates from the guide rail due to some factor, for example, collision with another machine, it is impossible to automatically return the vehicle to the guide rail. For this reason, users have demanded a guideless transport vehicle that can travel without a guide rail.

Further, in the concept of a next-generation transport system in which a plurality of AGVs cooperate with a change in a conveyed product in a variety of variable quantity production, an AGV technology that can run freely without a guide is indispensable. In order to study autonomous driving in recent years, the present applicant has produced an omnidirectional traveling three-wheel drive three-wheel steering test cart traveling on the indoor floor, and then self-guided (guideless driving). Technology is under study. Although there are many technical problems in such self-guidance technology, among them, a technology for recognizing one's position and posture (hereinafter, position identification technology) is the most important. AGV using such a guideless traveling technology is SN
V (Self Navigation Vehicle
e). However, this guideless driving technology includes
There is a problem of how to sense a traveling route. Here, sensing means that the SNV knows where it is running now (environment recognition).
It is thought that it will be possible for the automatic guided vehicle to perform position correction in the station, correct the deviation from the route during the transfer between processes, and to recover even when the self-position information is lost due to the influence of disturbance light etc. Can be This sensing is currently being studied in the laboratories of universities and the like, but the environment and uses are quite limited, and at present the definitive technology has not been established.

[0004] Just like humans, it is difficult to make a forward-looking judgment. The development of advanced artificial intelligence, such as the human brain, and a high-speed computer that predicts instantaneously is a challenge. Even if realized, the cost would be too high to attach to the AGV. Therefore, environment recognition is performed with limited recognition power. Currently, image processing is widely used. However, this image processing also requires considerable information processing and cost, and realization of environment recognition is likely to take some time.

It is desired that the position identification method be based on the following concept.

[0006] 1. Position identification is not continuous recognition but intermittent recognition.

[0007] 2. The processing is simplified as much as possible to prevent a reduction in the AGV determination speed and a delay in the overall processing.

[0008] 3. Reduce costs.

[0009] Based on the above concept, a position identification unit using a laser has been developed. The laser-based position recognition technology currently on the market has the following features.

[0010] 1. As shown in FIG. 7, special reflectors 1 called corner cubes are placed at four corners in a factory.

2. A laser 3 is emitted from the AGV 2. In this case, the launch direction of the laser is changed at a constant angular velocity,
It fires (scans) by tracing all directions.

3. Laser 3 fired is corner cube 1
, The reflected light is received, and the position is back-calculated from the light receiving angle at this time and the detected distance in the manner of triangulation.

This method is similar to the method in which a ship obtains latitude and longitude using a lighthouse, and since it is calculated using only angle data, there are few error factors and accuracy is high.

[0014]

A conventional non-contact sensor such as a laser judges a position by measuring a linear distance or the like with a partner. However, there are many obstacles in the factory, and if unmanned transport is performed while determining the position with a linear laser in such an environment, the vehicle can travel only in a very limited environment.

The present invention has been made in consideration of the above problems, and has as its object to provide a method for identifying a position of an automatic guided vehicle having a small error even when there is an obstacle.

Further, in the conventional example, since the laser beam is reflected from the AGV and scanned with respect to the corner cube, there is a disadvantage that a strong laser beam runs around the factory.

Another object of the present invention is to provide a method for identifying a position of an automatic guided vehicle, which can prevent a laser beam from running around a factory.

[0018]

Means for Solving the Problems According to a first aspect of the present invention, there is provided a method for identifying a position of an automatic guided vehicle for loading and automatically transporting a load in a room such as a factory or a warehouse. A reflector with higher light reflectance than the light reflectance is attached to the indoor wall surface of a warehouse or warehouse, and the laser range finder and the reflected light amount detection device attached to the automatic guided vehicle are rotated around the vertical axis at a predetermined angular velocity by a turning device. In this state, the laser is irradiated from the laser range finder, and the reflected light amount detecting device detects the amount of light emitted from the laser range finder and reflected by the indoor wall surface or the reflecting plate, When the light amount of the light received by the reflected light amount detecting device suddenly rises, the light irradiation point of the laser from the laser distance meter enters the one end of the surface of the reflecting plate from the indoor wall surface in the light amount increase detecting unit. Judge In the first distance detecting section, immediately after the first time point at which the light quantity rise detecting section has determined that the laser irradiation point has entered the surface of the reflecting plate, the first distance to the reflecting plate measured by the laser range finder is measured. When the light amount of the light received by the reflected light amount detecting device suddenly drops, the irradiation point of the laser from the laser distance meter is detected by the light amount decrease detecting unit at the other end of the surface of the reflecting plate. It is determined that the laser light has escaped from the surface to the indoor wall surface, and the second distance detection unit determines that the laser beam has fallen from the surface of the reflection plate by the light amount decrease detection unit immediately before the second time point. A second distance to the reflector measured by the range finder is detected, a turning angle detected by the turning device from the first time point to the second time point by the turning device is detected by a turning angle detection unit, and the turning is performed. An angle, the first distance and the second distance. There are computing the planar position of the AGV.

According to a second aspect of the present invention, there is provided:
What is claimed is: 1. A method for identifying a position of an automatic guided vehicle that automatically loads and loads cargo in a room such as a factory or a warehouse, comprising: a first reflecting portion having a first light reflectance on a wall surface of a room such as a factory or a warehouse; 2
A second reflecting portion having a light reflectance of each of the two reflecting portions is different from each other and set to be larger than the light reflectance of the indoor wall surface, a laser irradiation device attached to the automatic guided vehicle, and The reflected light amount detecting device is turned around a vertical axis at a predetermined angular velocity by a turning device, and in this state, a laser is irradiated from the laser irradiation device, emitted from the laser irradiation device, and emitted from the indoor wall surface or each of the reflecting portions. The amount of reflected light is detected by the reflected light amount detecting device, and the amount of light received by the reflected light amount detecting device rapidly rises to a first light amount corresponding to the light reflectance of one of the reflecting portions. The time point is detected by the first light amount change detection unit, and then the light amount of the light received by the reflected light amount detection device corresponds to the light reflectance of the other reflection unit from the light amount corresponding to the light reflectance of the one reflection unit. The second point in time when the amount of light Of detected at the light amount change detecting unit, the first rotation angle detected by the first pivot angle detector which pivots at pivot device from said first time point to the second point,
Further, a third time point at which the light amount of the light received by the reflected light amount detecting device sharply drops is detected by the third light amount change detecting unit, and the turning device turns from the second time point to the third time point. The second turning angle detected by the second turning angle detecting unit is detected, and the plane of the automatic guided vehicle is detected based on the first turning angle, the second turning angle, and the width of each reflecting unit stored in advance. Calculate the position.

The problem solving means according to claim 3 of the present invention comprises:
What is claimed is: 1. A method for identifying a position of an automatic guided vehicle that automatically loads and loads cargo in a room such as a factory or a warehouse, comprising: a first reflecting portion having a first light reflectance on a wall surface of a room such as a factory or a warehouse; 2
A second reflection portion having a light reflectance of each of the two reflection portions is different from each other and set to be greater than the light reflectance of the indoor wall surface, a laser distance meter attached to the automatic guided vehicle and The reflected light amount detecting device is turned around a vertical axis at a predetermined angular velocity by a turning device, and a laser is emitted from the laser range finder.After that, it is suitable when the automatic guided vehicle is at a short distance to the reflecting portion. A first position identification procedure and a second position identification procedure suitable for a case where the automatic guided vehicle is at a long distance from the reflection unit are switchably executed to calculate the planar position of the automatic guided vehicle. In the first position identification procedure, the reflected light amount detecting device detects the amount of light emitted from the laser rangefinder and reflected by the indoor wall surface or each of the reflecting portions, and received by the reflected light amount detecting device. While the amount of light rises sharply The first time point when the amount of light corresponding to the optical reflectivity of the reflective portion is detected by the first light amount change detecting unit,
Next, a second time when the light amount of the light received by the reflected light amount detecting device becomes the light amount corresponding to the light reflectance of the other reflecting portion from the light amount corresponding to the light reflectance of the one reflecting portion is a second light amount. The change is detected by the change detection unit, the first turning angle detected by the turning device from the first time point to the second time point is detected by the first turning angle detection unit, and the reflected light amount detection device detects the first turning angle. A third time point at which the light amount of the received light sharply drops is detected by the third light amount change detection unit, and a second turning angle at which the turning device turns from the second time point to the third time point. The second
The turning position detection unit detects the first turning angle, the second turning angle, and the plane position of the automatic guided vehicle based on the width of each reflecting unit stored in advance,
The second position identification step includes detecting the amount of light emitted from the laser range finder and reflected by the indoor wall surface or the two reflecting portions by the reflected light amount detecting device, and detecting the amount of light received by the reflected light amount detecting device. When the light amount of the laser light rises sharply, the light amount increase detection unit determines that the irradiation point of the laser from the laser distance meter has entered one end of the surface of one of the reflection units from the indoor wall surface, and the first In the distance detecting section, the first light point measured by the laser range finder immediately after the first time point at which the light quantity rise detecting section has determined that the laser irradiation point has entered the surface of the one reflecting section. 1 is detected, and when the amount of light received by the reflected light amount detecting device is suddenly decreased, the irradiation point of the laser from the laser distance meter is detected by the decreased light amount detecting unit. Pull out from the other end of the surface to the indoor wall It is determined that the laser range finder has come out, and the laser distance meter detects the laser light range finder immediately before the second time point at which the second light amount detection unit determines that the irradiation point of the laser has escaped from any one of the reflection unit surfaces. A second distance from the measured one of the reflecting portions is detected, a turning angle detected by the turning device from the first time to the second time is detected by a turning angle detecting portion, and the turning is detected. The plane position of the automatic guided vehicle is calculated based on an angle, the first distance, and the second distance.

According to a fourth aspect of the present invention, there is provided:
The distance to the indoor wall surface is measured with a laser range finder, and when the distance measurement result is a short distance, the plane position of the automatic guided vehicle is calculated by the first position identification procedure, and the distance measurement result is a long distance. In the case of, the planar position of the automatic guided vehicle is calculated in the second position identification procedure.

[0022] The problem solving means according to claim 5 of the present invention is as follows.
A changeover switch for switching between the first position identification procedure and the second position identification procedure is provided, and the changeover switch is switched according to the size of the room to be used.

[0023]

With the method for identifying a position of an automatic guided vehicle according to the first aspect of the present invention, it is not necessary to use corner cubes at four corners of a room as in the conventional example, and the four corners of a room can be effectively used for other purposes. Scattering of the laser due to a plurality of corner cubes can be prevented. Further, in particular, since the position is identified based on the distance information measured by using the laser distance meter, even when the distance to the reflector is relatively long, the distance information can have a certain accuracy. .

An obstacle is present in a part between the vehicle and the reflector, and the reflected light amount is detected even though the laser irradiation point moving on the surface of the reflector has not reached the other end. Even if the amount of light received by the device drops sharply, the turning point that the turning device has turned with the turning device from the first point to the second point is defined as the turning point when the steep drop point is the second point. , And position identification can be performed based on the actual measurement value, and erroneous calculation due to an obstacle can be prevented as compared with a case where the width of the reflector is calculated as a unique value.

According to the position identification method of the automatic guided vehicle according to the second aspect of the present invention, when the distance to the reflecting portion is short, the position of the automatic guided vehicle can be identified without using a laser range finder. No more worries about measurement errors specific to rangefinders,
Accurate position identification can be performed. Further, unlike the conventional example, it is not necessary to use the corner cubes at the four corners of the room, and the four corners of the room can be effectively used for other purposes, and the scattering of the laser due to the plurality of corner cubes can be prevented.
Further, in particular, since the position is identified based on the distance information measured by using the laser distance meter, even when the distance to the reflector is relatively long, the distance information can have a certain accuracy. .

According to a third aspect of the present invention, when the distance to the reflector is short, the planar position of the automatic guided vehicle is determined by the first position identification procedure. When the distance is long, the planar position of the automatic guided vehicle can be calculated by the second position identification procedure in the second position identification procedure, and the position identification accuracy can be maintained high both in the distance and near.

[0027]

【Example】

First Embodiment <Structure> FIG. 1 is a view showing a first embodiment of the present invention.
The automatic guided vehicle according to the present embodiment is for loading and automatically transporting luggage in a room such as a factory or a warehouse, and as shown in FIG. The vehicle includes a traveling wheel 12 and a laser measurement unit 13 mounted on the upper surface of the vehicle body 11.

The laser measuring unit 13 is, as shown in FIG. 2, a reflecting plate 1 installed on an indoor wall 17 of a factory or a warehouse.
The position of the vehicle is obtained from the positional relationship with the mark 8 (mark). The head 23 includes a laser range finder 21, a reflected light amount detecting device 22, and a position recognizing means 26;
And a turning device 25 for turning the rotating member 3 around the vertical axis 24.

The reflection plate 18 is made of a metal plate such as aluminum.
7 is set to a predetermined value that is significantly different from the light reflectance of No. 7. The width H1 of the reflection plate 18 is set accurately according to a desired design value, and the reflection plate 18 is accurately installed on the indoor wall surface 17 such as the factory or the warehouse.

As the laser range finder 21, a low-power safe one that does not require a protective device, such as a battery-powered ruby laser, is used. As shown in FIG. This is a general type including a photomultiplier tube 32 that picks up a reflected beam irradiated from the optical telescope 31 and reflected by the reflector 18. The reflected light amount detection device 22 uses a photoelectric conversion element whose output current or output voltage varies depending on the amount of received light. The turning device 25 uses an electrically driven turning actuator or the like, and performs a turning operation at a predetermined angular velocity.

The position recognizing means 26 is provided in the vehicle body 1.
1 for detecting the position of the reflected light
The light amount increase detection unit 35 detects that the light amount of the light received based on the output value obtained through the signal processing circuit 33, that is, the output current value or the output voltage value, sharply increases.
The first distance to the reflection plate 18 is detected by the laser distance meter 21 immediately after the first point in time when the light amount of the light received based on the detection signal from the light amount increase detection unit 35 sharply increases. A first distance detecting section 36 for detecting the amount of light received, based on an output value from the reflected light amount detecting device 22; The second distance for detecting the second distance to the reflector 18 measured by the laser distance meter 21 immediately before the second point in time when the amount of light received based on the detection signal from From the first point in time when the light amount of the received light suddenly rises to the second point in time when the light quantity of the received light suddenly rises, that is, the irradiation point (spot) of the laser moves on the surface of the reflecting plate 18 as a mark. Swivel 2
The turning angle detecting unit 39 for detecting the turning angle θ12 of turning at 5, and the position of the vehicle body 11 is calculated based on the detection information detected by the distance detecting units 36, 38 and the turning angle detecting unit 39. And a microcomputer chip as the arithmetic unit 41. The turning angle detection unit 39 has, for example, a timing unit, and measures the time required from the first time when the amount of received light sharply rises to the second time when the amount of light suddenly falls is measured by the time counting. Measured by means,
If the time and the predetermined turning angular velocity of the turning device 25 are integrated, the turning angle θ12 can be easily calculated. Alternatively, a general encoder may be used for the turning angle detection unit 39.

<Position Identification Method> Next, a method for identifying the position of the automatic guided vehicle will be described. First, while the head unit 23 is turned around the vertical axis 24 at a predetermined angular velocity by the turning device 25, the laser is directed and irradiated by the optical telescope 31 of the laser distance meter 21. Then, as shown in FIG. 4, the irradiation point (spot) of the laser is directed to the indoor wall surface 17 such as a factory or a warehouse by an arrow α.
1 and then from one end of the reflector 18 to its surface. At this time, since the light reflectance of the reflection plate 18 is extremely large compared to the light reflectance of the indoor wall surface 17, the amount of light received by the reflected light amount detecting device 22 sharply increases, and the reflected light amount detecting device 22 The output value obtained through the signal processing circuit 33 greatly changes. Based on the change in the output value, the light amount increase detecting unit 35 of the position recognizing unit 26
Detects that the amount of received light has risen sharply.
Then, immediately after the first time point when the light amount of the light received based on the detection signal from the light amount increase detection unit 35 sharply increases,
The first distance detection unit 36 uses the laser distance meter 21 to
The first distance up to 8 is detected. It should be noted that even after the first distance is detected by the first distance detection unit 36, the laser distance meter 21 may be used.
Distance measurement is continuously performed.

After a lapse of a predetermined time, the head 23 is turned by the turning device 25, so that the laser irradiation point (spot) moves on the surface of the reflector 18 in the direction of arrow α2, and then the other end of the reflector 18 Again from the interior of the factory or warehouse 17
Get out. At this time, since the light reflectance of the indoor wall surface 17 is extremely small as compared with the light reflectance of the reflection plate 18,
The light amount of the light received by the reflected light amount detecting device 22 sharply decreases, and the output value obtained from the reflected light amount detecting device 22 via the signal processing circuit 33 changes greatly. On the basis of the change in the output value, the light amount drop detection unit 37 of the position recognition unit 26
It detects that the amount of received light has dropped sharply. Then, at a second point in time when the light amount of the light received based on the detection signal from the light amount decrease detection unit 37 sharply decreases, the second distance to the reflection plate 18 measured by the laser distance meter 21 immediately before the second time point is calculated. Detected by the second distance detection unit 38.

Then, based on the distance information detected by the distance detecting sections 36 and 38, the calculating section 41 calculates the plane position of the vehicle body 11. Here, as shown in FIG. 4, a laser irradiation point on the surface of the reflecting plate 18 is defined as H1 where H1 is a unique width of the reflecting plate 18, and an origin Pi (0, 0) is a plane position of one end of the reflecting plate 18. The direction of movement of the reflector 18 is taken as the X-axis, the direction of radiation of the reflector 18 is taken as the Y-axis, and the plane position of the other end of the reflector 18 is Po
(H1,0), the plane position of the vehicle body 11 is defined as Pa (x,
y, θsnv), the angle between the line segments Po to Pa and the reflector 18 is θa, and the angle between the line segments Pi to Pa and the reflector 18 is θ
b, the turning angle θ12, Pa obtained by the turning angle detection unit 39
Assuming that a second distance between the vehicle body 11 and Po is L1 and a first distance between Pa and Pi is L2, the plane position Pa
(X, y, θsnv) can be calculated as follows.

[0035]

(Equation 1)

Here, θα is an offset angle with respect to the vehicle body 11, and

[0037]

(Equation 2)

Is as follows. As described above, since laser positioning is performed using a mark having a predetermined width serving as a coordinate reference,
Position identification can be performed using a simple calculation formula.

By the way, an obstacle may be present at a part between the vehicle and the reflection plate 18, and when the obstacle is irradiated with the laser, the amount of reflected light may be small. Then, although the irradiation point of the laser moving on the surface of the reflection plate 18 has not yet reached the other end,
The amount of light received by the reflected light amount detection device 22 drops rapidly, and the signal processing circuit 33
Then, the output value obtained through the above-mentioned step changes greatly, and the L2 is detected at this point. Therefore, if H1 as the eigenvalue is directly used as a calculation element, a significant erroneous calculation will result. Therefore, in the present embodiment, instead of processing the value of H1 as an eigenvalue, the calculation is performed one by one in correspondence with the time when L1 and L2 are actually measured. Specifically, first, the turning angle detection unit 3
In 9, the time required from the first time when the amount of the received light sharply rises to the second time when the amount of light suddenly falls is measured, and the time and a predetermined turning angular velocity of the turning device 25 are determined. And the turning angle θ12 during which the irradiation point (spot) of the laser moves on the surface of the reflector 18 as a mark.
Is calculated. Then, H1 can be easily obtained from θ12, L1 and L2 by the following equation.

[0040]

(Equation 3)

According to the above calculation, there is an obstacle in a part between the vehicle and the reflector 18 and the irradiation point of the laser moving on the surface of the reflector 18 reaches the other end. If the amount of light received by the reflected light amount detection device 22 suddenly drops despite the absence, the length of the detected mark is calculated in accordance with such a situation in accordance with the actual situation, and the position identification is performed based on this. Erroneous calculation due to an obstacle can be prevented. Thereafter, the laser irradiation point moves on the indoor wall surface 17 of a factory or a warehouse, and the above operation may be repeated each time the head unit 23 makes one turn.

As described above, in the present embodiment, even in a factory having many obstacles, it is possible to identify a position with a small error and scan in a narrow place. Further, unlike the conventional example, it is not necessary to use the corner cubes at the four corners of the room, and the four corners of the room can be effectively used for other purposes, and the scattering of the laser due to the plurality of corner cubes can be prevented. In the present embodiment, since the distance information to the mark measured using the laser distance meter 21 is used as a parameter, even when the distance to the mark is relatively long, the distance information can have a certain accuracy. Suitable for indoor use in large areas.

[Second Embodiment] <Structure> In an automatic guided vehicle according to a second embodiment of the present invention, the position of the vehicle is obtained by using a laser similarly to the first embodiment shown in FIG. It has a laser measurement unit 13. However, in the first embodiment, the laser distance meter 2
Although the distance to both end points of the reflection plate 18 was measured at 1, there is a certain error in the ordinary laser distance measurement, so that accurate position identification may be difficult. Therefore, in the present embodiment, an improvement is added to solve such a problem.

Reflector 18 (mark) in this embodiment
As shown in FIG. 5, a first reflecting portion 18A having a first light reflectance and a second reflecting portion 18B having a second light reflectance significantly different from the first light reflectance are provided. Be adjacent. The light reflectance of each of the reflecting portions 18A and 18B is set to be significantly different from the light reflectance of the indoor wall surface 17 of a factory or a warehouse used. The two reflection portions 18A of the reflection plate 18,
The widths H11 and H12 of the 18B are set exactly as desired design values.

Then, the laser measuring unit 1 of this embodiment
Reference numeral 3 denotes a head unit 2 as in the first embodiment shown in FIG.
3 and a turning device 25 for turning the head portion 23 around the longitudinal axis 24.

As shown in FIG. 6, a laser irradiator 45 having an optical telescope is provided in the head 23, and each reflector 18 of the reflector 18 emitted from the laser irradiator 45 is provided.
A reflected light amount detecting device 46 for detecting the amount of the reflected light reflected at A and 18B, a position recognizing unit 47 for recognizing the position of the vehicle body 11 based on the received light information received by the reflected light amount detecting device 46; It has.

As in the first embodiment, the reflected light amount detecting device 46 uses a photoelectric conversion element having an output current or an output voltage that differs depending on the amount of received light.

The position recognizing means 47 is disposed, for example, in the head section 23, and is based on an output value obtained from the reflected light amount detecting device 46 via the signal processing circuit 48, ie, an output current value or an output voltage value. A first light amount change detecting unit 51 for detecting that the amount of received light has risen rapidly and has changed to be equal to the amount of reflected light from the first reflecting unit 18A; A second method for detecting that the amount of light received based on the output value has changed abruptly from the amount of light reflected from the first reflector 18A to be equal to the amount of light reflected from the second reflector 18B. Light amount change detection unit 52 and the first light amount change detection unit 51
From when the light amount of the reflected light is suddenly changed until the second light amount change detecting unit 52 detects the sudden change in the light amount of the reflected light, that is, when the laser irradiation point (spot) is
A first turning angle detecting unit 53 for detecting a turning angle θ12 of turning by the turning device 25 while moving on the surface of the first reflecting unit 18A of FIG. A third light amount change detecting unit 54 for detecting that the light amount of the light received based on the output value obtained through 48 suddenly drops from the light amount of the reflected light from the second reflecting unit 18B; The second light amount change detecting unit 52 detects the sudden change in the amount of reflected light, and then the third light amount change detecting unit 5.
4 is turned by the turning device 25 until the laser beam 4 detects a sudden change in the amount of reflected light, that is, while the irradiation point (spot) of the laser is moving on the surface of the second reflecting portion 18B of the reflecting plate 18. A second turning angle detecting unit 55 for detecting the angle θ23, and a microcomputer chip as a calculating unit 56 for calculating the position of the vehicle body 11 based on the detection information detected by the turning angle detecting units 53 and 55. Is provided. Each of the turning angle detection units 53 and 55 has, for example, a time measuring unit, and the first turning angle detection unit 53
In the case of (1), the time required for the amount of reflected light to suddenly change from the first reflecting portion 18A to the next sharply changing amount to the second reflecting portion 18B, In the case of the turning angle detection unit 55, the time required until the amount of reflected light suddenly changes from the second reflecting unit 18B to the next sharp fall is measured by the timing means, respectively. If the time and the predetermined turning angular velocity of the turning device 25 are integrated, the turning angles θ12 and θ23 can be easily calculated. Alternatively, a general encoder may be used for each of the turning angle detection units 53 and 55.

<Position Identification Method> Next, a description will be given of a position identification method of the automatic guided vehicle. First, the laser irradiating device 45 directs and irradiates a laser while rotating the head unit 23 around the vertical axis 24 at a predetermined angular velocity by the circling device 25. Then, as shown in FIG. 5, the laser irradiation point (spot)
Moves on the indoor wall surface 17 of a factory or a warehouse in the direction of arrow α1, and then moves from one end of the first reflection portion 18A of the reflection plate 18 to the surface thereof. At this time, the first reflecting portion 18A
Is extremely large as compared with the light reflectance of the indoor wall surface 17, the amount of light received by the reflected light amount detecting device 46 rapidly rises, and the signal processing circuit 48 is transmitted from the reflected light amount detecting device 46 to the signal processing circuit 48. The output value obtained through this greatly changes. Based on this change in the output value, the first light amount change detecting section 51 of the position recognition means 47 detects that the amount of received light has risen sharply.

After a lapse of a certain time, the head 23 is turned by the turning device 25, so that the irradiation point (spot) of the laser moves on the surface of the first reflecting portion 18A in the direction of the arrow α2a, and then the first From the other end of the reflector 18A, it enters one end of the second reflector 18B. At this time, both reflection portions 1
Since the light reflectances of 8A and 18B are set to be different from each other, the amount of light received by the reflected light amount detecting device 46 sharply increases, and the reflected light amount detecting device 46 outputs a signal processing circuit 48.
The output value obtained through the above changes greatly. Based on the change in the output value, the second light amount change detecting unit 52 of the position recognizing unit 47 detects that the light amount of the received light has changed abruptly. Then, in the first turning angle detection unit 53, the irradiation point (spot) of the laser is changed to the first reflection unit 1 of the reflection plate 18.
The turning angle θ12 of turning by the turning device 25 while moving on the surface of 8A is detected.

After a certain period of time, the head 23 is turned by the turning device 25, so that the irradiation point (spot) of the laser moves on the surface of the second reflecting portion 18B in the direction of the arrow α2b. From the other end of the reflecting portion 18B again escapes to the interior wall surface 17 of a factory or a warehouse. At this time, since the light reflectance of the indoor wall surface 17 is extremely small as compared with the light reflectance of the second reflecting portion 18B, the light amount of the light received by the reflected light amount detecting device 46 rapidly decreases, and the reflected light amount The output value obtained from the detection device 46 via the signal processing circuit 48 changes greatly. Based on this change in the output value, the third light amount change detection unit 54 of the position recognition unit 47 detects that the light amount of the received light has dropped sharply. Then, in the second turning angle detecting unit 55, the turning angle θ23 turned by the turning device 25 while the irradiation point (spot) of the laser moves on the surface of the second reflecting unit 18B of the reflecting plate 18. Is detected.

Thereafter, the calculating section 56 calculates the plane position of the vehicle body 11 based on the turning angle information detected by the turning angle detecting sections 53 and 55. Here, as shown in FIG. 5, the unique width of the first reflecting portion 18A is H11, and the second reflecting portion 1
8B is H12, and the first reflecting portion 18
With the plane position of one end of A as the origin Pi (0, 0), the moving direction of the laser irradiation point on the surface of the reflecting plate 18 is taken as the X axis, and the radiation direction of the reflecting plate 18 is taken as the Y axis. 18A
The plane position of the other end of the second reflecting portion 18B is P1 (H11,0), and the plane position of the other end of the second reflecting portion 18B is P2 (H11 + H12,
0), the plane position of the vehicle body 11 is defined as Pa (x, y, θsn).
v), the angle between the line segments P2 to Pa and the reflection plate 18 is θa,
The angle between the line segments P1 to Pa and the second reflecting portion 18B is θ
b, the angle between the line segments P1 to Pa and the first reflecting portion 18A is θc, the angle between the line segments Pi to Pa and the reflecting plate 18 is θd,
The turning angle obtained by the first turning angle detection unit 53 is θ12,
The turning angle obtained by the second turning angle detection unit 55 is θ23,
The first distance between Pa and Pi is L11, the second distance between Pa and P1 is L12, the third distance between Pa and P2 is L13, and both reflecting portions 18A and 18B of the reflecting plate 18 are provided. Are respectively H11 and H12, the plane position Pa (x, y, θsnv) of the vehicle body 11 can be calculated as follows.

[0053]

(Equation 4)

However,

[0055]

(Equation 5)

Is as follows. As described above, since laser positioning is performed using a mark having a predetermined width serving as a coordinate reference,
The position identification of the vehicle body 11 can be performed without using the laser distance meter used in the first embodiment. Therefore,
There is no need to worry about measurement errors peculiar to the laser distance meter, and accurate position identification can be performed. Further, unlike the conventional example, it is not necessary to use corner cubes in all four corners of a room, and the four corners of the room can be effectively used for other purposes, and scattering of laser beams by a plurality of corner cubes can be prevented.
In the case where the position identification is performed only by measuring the angles of the reflecting portions 18A and 18B as two marks without performing the distance measurement as in the present embodiment, if the distance from the mark is too far, the angle measurement is not performed. Accuracy deteriorates. Therefore,
The position identification method of the present embodiment is effective for a case where the distance from the mark is relatively short, at least within 1000 mm, preferably within 500 mm.

[Modifications] (1) In the first embodiment (first position identification procedure), the distance to the mark is compared by using the distance information for the mark measured using the laser distance meter 21 as a parameter. Even if the target is long, the distance information can have a certain accuracy. In the second embodiment (second position identification procedure), the reflection unit 1 serving as two marks without measuring the distance is used.
By performing position identification only by angle measurement for 8A and 18B, there is no need to worry about measurement errors specific to laser rangefinders.
Accurate position identification could be performed for a relatively short distance mark. In view of the characteristics of both of these embodiments, both position identification methods may be combined. Specifically, for example, the distance to the indoor wall surface is always measured by the laser range finder 21 and, if the distance measurement result is a short distance such as less than 500 mm, for example, the distance is measured as in the second embodiment. The position identification was performed only by measuring the angles of the reflecting portions 18A and 18B, and when the distance measurement result was a long distance such as 500 mm or more, the measurement was performed using the laser distance meter 21 as in the first embodiment. If the position identification is performed using the distance information to the mark as a parameter, the position identification accuracy can be improved in both the near and far directions, regardless of the position of the vehicle body 11 with respect to the indoor wall surface. In this case, in this case, the laser distance meter 21, the reflected light amount detecting device 22, the light amount rising detecting unit 35, and the light amount falling detecting unit 37 of the first embodiment are used.
May be used as they are as the laser irradiation device 45, the reflected light amount detection device 45, the first light amount change detection unit 51, and the third light amount change detection unit 54 of the second embodiment. The turning angle detected by the turning angle detecting unit 39 of the first embodiment is the sum of the values detected by the first turning angle detecting unit 53 and the second turning angle detecting unit 55 of the second embodiment. Do it.

(2) Alternatively, a changeover switch for switching between the position identification method of the first embodiment (first position identification procedure) and the position identification method of the second embodiment (second position identification procedure) is provided. If it is configured such that the operator can switch according to the size of the room to be provided and used, the use in a small room and the use in a large room can be selectively used with a simple configuration.

[0059]

According to the first aspect of the present invention, the laser range finder and the reflected light amount detecting device are turned, and in this state, the laser is irradiated from the laser range finder to detect the reflected light amount on the indoor wall surface or the reflecting plate. Immediately after the reflected light amount rises sharply, the first distance to the reflector is detected by the laser distance meter, and when the reflected light amount falls sharply, the first distance to the reflector by the laser distance meter is measured immediately before that point. Since the distance of the automatic guided vehicle is detected based on the turning angle, the first distance, and the second distance, the plane position of the automatic guided vehicle is calculated based on the turning angle, the first distance, and the second distance. It is not necessary to use the corner cubes at the four corners of the room, and the wall surface of the room can be effectively used for other purposes, and the scattering of the laser due to a plurality of corner cubes can be prevented. Further, in particular, since the position is identified based on the distance information measured by using the laser distance meter, even when the distance to the reflector is relatively long, the distance information can have a certain accuracy. .

An obstacle is present at a part between the vehicle and the reflector, and the reflected light amount is detected even though the laser irradiation point moving on the surface of the reflector has not reached the other end. Even if the amount of light received by the device drops sharply, the turning point that the turning device has turned with the turning device from the first point to the second point is defined as the turning point when the steep drop point is the second point. In this case, the position can be identified based on the actual measurement value, and an erroneous calculation due to an obstacle can be prevented as compared with the case where the width of the reflector is calculated as an eigenvalue.

According to the second aspect of the present invention, two reflecting portions having different light reflectivities are provided on the indoor wall surface of a factory or a warehouse, and the laser irradiating device and the reflected light amount detecting device are turned. The device irradiates a laser to detect the amount of reflected light on the indoor wall surface or each reflecting portion. The first time when the amount of reflected light is the amount of light corresponding to the light reflectance of one of the reflecting portions, A second time point when the light amount corresponding to the light reflectance of the other reflecting portion is detected from the light amount corresponding to the light reflectance of the reflecting portion, respectively, and the second time point turned from the first time point to the second time point is detected. 1 is detected, a third time point at which the amount of reflected light is sharply reduced is detected, a second turning angle from the second time point to the third time point is detected, and the first turning angle is detected. Based on the angle, the second turning angle, and the width of each of the reflecting portions stored in advance. Since the planar position of the automatic guided vehicle is calculated, the position of the automatic guided vehicle can be identified without using a laser range finder. Is eliminated, and accurate position identification can be performed. Further, unlike the conventional example, it is not necessary to use a plurality of corner cubes, and the interior wall surface can be effectively used for other purposes, and laser scattering by the plurality of corner cubes can be prevented. Further, in particular, since the position is identified based on the distance information measured by using the laser distance meter, even when the distance to the reflector is relatively long, the distance information can have a certain accuracy. This has the effect.

According to claims 3 to 5 of the present invention,
A first position identification procedure suitable for when the automatic guided vehicle is at a short distance to the reflector, and a second position identification procedure suitable for when the automatic guided vehicle is at a long distance to the reflector. When the distance to the reflector is short, the planar position of the automatic guided vehicle is calculated by the first position identification procedure, and when the distance is long, the unmanned carrier is calculated by the second position identification procedure. The plane position of the carrier can be calculated, and the position identification accuracy can be maintained high both in the near and far directions. In particular, claim 4
According to this, the first position identification procedure and the second position identification procedure can be automatically switched based on the measurement distance to the indoor wall surface by the laser range finder, and the accuracy can be maintained reliably. On the other hand, according to the fifth aspect, the first position identification procedure and the second position identification procedure can be switched with a simple configuration such as a changeover switch, so that the cost of the automatic guided vehicle can be reduced.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an automatic guided vehicle according to a first embodiment of the present invention.

FIG. 2 is a perspective view showing a position identifying operation of the automatic guided vehicle according to the first embodiment of the present invention.

FIG. 3 is a functional block diagram showing the inside of a head portion of the automatic guided vehicle according to the first embodiment of the present invention.

FIG. 4 is an explanatory diagram showing a position identification principle of the automatic guided vehicle according to the first embodiment of the present invention.

FIG. 5 is a functional block diagram showing the inside of a head portion of an automatic guided vehicle according to a second embodiment of the present invention.

FIG. 6 is an explanatory diagram showing a position identification principle of an automatic guided vehicle according to a second embodiment of the present invention.

FIG. 7 is a perspective view showing a position identification operation of a conventional automatic guided vehicle.

[Explanation of symbols]

 Reference Signs List 17 Indoor wall surface 18 Reflector 18A First reflector 18B Second reflector 21 Laser rangefinder 22 Reflection light quantity detector 24 Vertical axis 25 Rotating device 35 Light quantity rise detector 36 First distance detector 37 Light quantity fall detector 38 second distance detecting unit 39 turning angle detecting unit 45 laser irradiation device 46 reflected light amount detecting device 51 first light amount change detecting unit 52 second light amount change detecting unit 53 first turning angle detecting unit 54 third light amount Change detection unit 55 Second turning angle detection unit

Continuation of front page (58) Field surveyed (Int.Cl. ⁷ , DB name) G05D 1/02

Claims (5)

(57) [Claims] 1. A method for identifying a position of an automatic guided vehicle that automatically loads and loads cargo in a room such as a factory or a warehouse, wherein a light reflectance greater than the light reflectance of the indoor wall surface of the factory or the warehouse is provided. Attach a reflector plate, rotate the laser range finder and the reflected light amount detection device attached to the automatic guided vehicle around the vertical axis at a predetermined angular velocity with a turning device, and irradiate laser from the laser range finder in this state, The amount of light emitted from the laser rangefinder and reflected by the indoor wall surface or the reflection plate is detected by the reflected light amount detection device, and when the amount of light received by the reflected light amount detection device rapidly increases, The light amount increase detecting unit determines that the irradiation point of the laser from the laser rangefinder has entered one end of the surface of the reflector from the indoor wall surface, and the first distance detecting unit determines that the light amount increase detecting unit Is a laser Immediately after the first time point at which it is determined that the irradiation point has entered the reflector surface, a first distance to the reflector measured by the laser range finder is detected. When the light amount suddenly decreases, the light amount decrease detection unit determines that the irradiation point of the laser from the laser distance meter has escaped from the other end of the surface of the reflection plate to the indoor wall surface, and detects the second distance. The second light quantity detecting unit determines that the irradiation point of the laser has escaped from the surface of the reflecting plate;
Detecting a second distance to the reflector measured by the laser range finder immediately before the time point, and detecting a turning angle of the turning device turned by the turning device from the first time point to the second time point. A position identification method of the automatic guided vehicle, wherein the automatic detection unit calculates a planar position of the automatic guided vehicle based on the turning angle, the first distance, and the second distance. 2. A method for identifying a position of an automatic guided vehicle that loads and automatically transports a load in a room such as a factory or a warehouse, wherein the first wall has a first light reflectance on a wall surface of the room such as a factory or a warehouse.
And a second reflector having a second light reflectivity, wherein the respective light reflectivities of the two reflectors are different from each other and are set to be larger than the light reflectivity of the indoor wall surface, and are attached to the automatic guided vehicle. The laser irradiation device and the reflected light amount detection device are turned around a vertical axis at a predetermined angular velocity by a turning device. In this state, laser is irradiated from the laser irradiation device, and the laser light is emitted from the laser irradiation device and the indoor wall surface is emitted. Alternatively, the amount of light reflected by each of the reflecting portions is detected by the reflected light amount detecting device, and the amount of light received by the reflected light amount detecting device rapidly rises and the amount of light corresponding to the light reflectance of one of the reflecting portions. Became the first
Is detected by the first light amount change detecting unit, and then the light amount of the light received by the reflected light amount detecting device is changed from the light amount corresponding to the light reflectance of the one reflecting unit to the light reflectance of the other reflecting unit. A second time point at which the corresponding light amount has been reached is detected by a second light amount change detection unit, and a first turning angle of the turning by the turning device from the first time point to the second time point is set to a first time. And a third time point at which the amount of light received by the reflected light amount detecting device suddenly drops is detected by a third light amount change detecting unit. From the second time point, the third time point The second turning angle detected by the turning device by the turning device up to the time point is detected by the second turning angle detection unit, and the first turning angle, the second turning angle, and the width of each of the reflection units stored in advance are detected. A position identification method of the automatic guided vehicle, which calculates a planar position of the automatic guided vehicle based on the equation. 3. A method for identifying a position of an automatic guided vehicle that loads and automatically transports a load in a room such as a factory or a warehouse, wherein the first surface of the indoor wall of the factory or the warehouse has a first light reflectance.
And a second reflector having a second light reflectivity, wherein the respective light reflectivities of the two reflectors are different from each other and are set to be larger than the light reflectivity of the indoor wall surface, and are attached to the automatic guided vehicle. The obtained laser range finder and the reflected light amount detection device are turned around a vertical axis at a predetermined angular velocity by a turning device, and a laser is emitted from the laser range finder. And a second position identification procedure suitable for a case where the automatic guided vehicle is located at a long distance from the reflection unit. The first position identification procedure comprises: detecting the amount of light emitted from the laser rangefinder and reflected by the indoor wall surface or each of the reflection units with the reflected light amount detection device; Of the light received by the reflected light detector The amount became rapidly rises to the amount of light corresponding to the light reflectance of one reflecting portion first
Is detected by the first light amount change detecting unit, and then the light amount of the light received by the reflected light amount detecting device is changed from the light amount corresponding to the light reflectance of the one reflecting unit to the light reflectance of the other reflecting unit. A second time point at which the corresponding light amount has been reached is detected by a second light amount change detection unit, and a first turning angle of the turning by the turning device from the first time point to the second time point is set to a first time. And a third time point at which the amount of light received by the reflected light amount detecting device suddenly drops is detected by a third light amount change detecting unit. From the second time point, the third time point The second turning angle detected by the turning device by the turning device up to the time point is detected by the second turning angle detection unit, and the first turning angle, the second turning angle, and the width of each of the reflection units stored in advance are detected. The planar position of the automatic guided vehicle is calculated based on the second position identification procedure. When the amount of light emitted from the laser rangefinder and reflected by the indoor wall surface or the two reflecting portions is detected by the reflected light amount detecting device, and the amount of light received by the reflected light amount detecting device rapidly increases. The light amount rise detecting unit determines that the irradiation point of the laser from the laser distance meter has entered one end of the surface of one of the reflecting units from the indoor wall surface, and the first distance detecting unit determines that the light amount Immediately after the first point in time when the ascending detecting section has determined that the laser irradiation point has entered the surface of the one reflecting section, the first distance to the one reflecting section measured by the laser range finder is detected immediately after the first point in time. When the light amount of the light received by the reflected light amount detecting device suddenly drops, the irradiation point of the laser from the laser distance meter is detected by the light amount decrease detecting unit from the other end of the surface of any of the reflecting units to the room. Judging that it has escaped to the wall, the second The distance detector, the laser light meter measures any one of the reflections immediately before the second time point at which the light amount drop detector determines that the irradiation point of the laser has escaped from the surface of the one of the reflectors. A second distance to the section, a turning angle detected by the turning device from the first time point to the second time point is detected by a turning angle detection section, and the turning angle and the first distance are detected. And a position identification method of the automatic guided vehicle, wherein a planar position of the automatic guided vehicle is calculated based on the second distance. 4. A method of measuring a distance to a wall surface of a room with a laser distance meter, and calculating a plane position of the automatic guided vehicle in the first position identification procedure when the distance measurement result is a short distance. 4. The method of claim 3, wherein when the measurement result is a long distance, the planar position of the automatic guided vehicle is calculated in the second position identification procedure. 5. 5. The position of the automatic guided vehicle according to claim 3, further comprising a changeover switch for switching between the first position identification procedure and the second position identification procedure, and switching the changeover switch according to the size of a room to be used. Identification method.