WO2022190628A1 - Conveyance platform detection device and conveyance platform detection system comprising same, conveyance platform detection method, and conveyance platform detection program - Google Patents

Abstract

In the present invention, a conveyance state detection device (10) detects a conveyance platform (30) that is being carried by a forklift truck (20) in a state of bearing a load (31). The conveyance state detection device comprises: a distance measurement unit (14); and a control unit (13). The distance measurement unit (14) measures the distance to an object according to the amount of reflected light of the light that is projected onto the object from a lighting unit (11). The control unit (13) determines whether the object is the conveyance platform (30) on the basis of the distance to the object as measured by the distance measurement unit (14).

Description

CONVEYOR DETECTION DEVICE AND CONVEYOR DETECTION SYSTEM INCLUDING THE SAME, CONVEYOR DETECTION METHOD, CONVEYOR DETECTION PROGRAM

The present invention relates to, for example, a carriage detection device that detects a carriage that is transported with a load on it, a carriage detection system including the same, a carriage detection method, and a carriage detection program.

2. Description of the Related Art In recent years, a forklift or the like has been widely used as a transport device for lifting and transporting a load loaded on a transport platform such as a pallet together with the transport platform.
Among such transport devices, there is a forklift equipped with an object detection device that detects objects existing in the surroundings (see, for example, Patent Document 1).
An object detection device described in Patent Literature 1 detects the position of an object (obstacle, wall, etc.) that hinders the movement of a forklift by processing images captured by a stereo camera. In order to avoid collision with such an object, the main controller of the forklift performs deceleration processing based on the detection result of the object detection device.

JP 2020-57258 A

However, the conventional conveying apparatus has the following problems.
That is, in the conveying apparatus disclosed in the above publication, images taken by a stereo camera are processed to detect the position and size of an object. However, it is difficult to accurately determine whether the detected object is a platform such as a pallet transported by a forklift or the like.

For example, if a black pattern or the like is written on the side of the detected object, the stereo camera can determine whether the part is a receiving part such as a hole into which the arm part of a conveying device such as a forklift is inserted. It was difficult to make a judgment even by image processing the image taken by.
SUMMARY OF THE INVENTION It is an object of the present invention to provide a carriage detection apparatus capable of accurately determining whether or not a detected object is a carriage, a carriage detection system including the same, a carriage detection method, and a carriage detection program. is to provide

A carriage detection device according to a first aspect of the present invention is a carriage detection device that detects a carriage that is conveyed by a conveyance device with a load on it, and includes a distance information acquisition unit and a determination unit. there is The distance information acquisition unit acquires distance information to the object according to the amount of reflection of electromagnetic waves irradiated from the lighting device to the object. The determination unit determines whether the object is the carriage based on the distance information to the object acquired by the distance information acquisition unit.

Here, for example, it is obtained from a TOF (Time of Flight) sensor that receives the reflected light of light emitted toward the object from an LED (Light Emitting Diode) as a light source and measures the distance to the measurement object. Using distance information to the object, it is determined whether the object is a carriage.
Here, the carriage detection device of the present invention may be mounted on a transport device such as a forklift or a transport robot, or may be provided as a separate device from the transport device.

Further, the carriage to be judged has a receiving part such as a hole or a concave part into which an arm part of a carriage such as a forklift is inserted, regardless of the material such as wood or resin.
Electromagnetic waves emitted from lighting equipment include, for example, light in a broad sense (ultraviolet light, visible light, infrared light), γ (gamma) rays with shorter wavelengths than light, X-rays, microwaves with longer wavelengths than light, and broadcasting Including radio waves (short wave, medium wave, long wave), ultrasonic waves, elastic waves, quantum waves, etc.

The distance information acquisition unit may be configured to detect reflection of electromagnetic waves to calculate distance information, or may be configured to acquire distance information from a distance sensor or the like provided as an external device, for example. good.
As a result, for example, even if a black pattern or the like is written on the side surface of an object placed on the floor, the characteristics of the transport table transported by the transport device (for example, the arm part of the transport device, etc. can be inserted) The presence or absence of a receiving portion such as a hole or recess) can be detected using distance information.
As a result, it is possible to accurately determine whether or not the detected object is the carriage.

A carriage detection device according to a second aspect of the invention is the carriage detection device according to the first aspect of the invention, wherein the carriage has a receiving portion into which an arm member of the transportation device is inserted. Using the distance information, the determination unit determines whether or not the object is a carriage according to at least one of the presence/absence, size, and position of the receiving portion.
As a result, by detecting the receiving part, which is the main characteristic part of the carriage, using the distance information, it is possible to determine whether the object is the carriage based on the presence or absence, size, position, etc. of the receiving part. can be determined.

A carriage detection apparatus according to a third aspect is the carriage detection apparatus according to the first or second aspect, wherein the determination unit determines at least the presence, size, and position of the receiving unit using the distance information. Depending on one, it is determined that the object is either a single carriage, a carriage with a load on it, or an object other than a carriage.
As a result, the state of the carriage (single unit, loaded, not carriage) can be accurately determined according to the presence/absence, size, position, etc. of the receiving portion detected using the acquired distance information. can.

A carriage detection device according to a fourth invention is the carriage detection device according to any one of the first to third inventions, wherein the determination unit uses distance information to determine whether the object is placed. A floor surface is detected, and an object having a height above the floor surface is detected as a carrier candidate.
Accordingly, by detecting the floor surface on which the object is placed using the acquired distance information, an object having a height above the floor surface can be detected as a carrier candidate.

A carriage detection apparatus according to a fifth aspect of the invention is the carriage detection apparatus according to the fourth aspect, wherein the determination unit determines the outer shape of the object detected as the carriage candidate based on the distance information. set.
Thus, the acquired distance information can be used to accurately set the outer shape of the object detected as the carriage candidate.

A carriage detection apparatus according to a sixth aspect of the invention is the carriage detection apparatus according to the fifth aspect, wherein the determination unit performs binarization obtained based on distance information or brightness information of an image of an object. Use the processed data to set the outline.
Thereby, the outer shape of the object can be set using binarized data obtained based on the distance information or the brightness information of the image of the object.

A carriage detection apparatus according to a seventh aspect is the carriage detection apparatus according to the fifth or sixth aspect, wherein when binarized data cannot be obtained in the determination unit, The exposure time for irradiating/receiving the irradiated electromagnetic wave is adjusted.
As a result, when binarized data cannot be obtained, the exposure time for irradiating and receiving electromagnetic waves emitted from the illumination device is adjusted to obtain properly binarized data. , the outline of the object can be set accurately.

A carriage detection device according to an eighth invention is the carriage detection device according to any one of the fifth to seventh inventions, wherein the determination section has a receiving section formed based on the set outer shape. Set the detection plane that is assumed to be
Thereby, it is possible to set the detection surface where the receiving part is supposed to be located from the set outline.

A carriage detection device according to a ninth aspect of the invention is the carriage detection device according to the eighth aspect, wherein the determination unit determines whether or not it is a carriage according to depth information of the receiving portion on the detection surface. judge.
Accordingly, by detecting the presence or absence of depth on the detection surface using the acquired distance information, it is possible to accurately determine whether or not the object is a carriage having a receiving portion.

A carriage detection device according to a tenth aspect is the carriage detection device according to any one of the first to ninth aspects, wherein detection data of a carriage determined to be a carriage by the determination unit is further provided with a storage unit for storing the
As a result, by registering the data (outer shape, size, position of the receiving part, etc.) of the carriage determined to be the carriage in the storage unit, for example, the carriage and the carriage placed on the carriage afterward can be stored in the storage unit. It is possible to determine the balance of the cargo by recognizing the boundary with the loaded cargo.

A carriage detection device according to an eleventh invention is the carriage detection device according to any one of the first to tenth inventions, wherein the electromagnetic waves are infrared rays.
Accordingly, by acquiring the distance information calculated according to the amount of reflected infrared rays, it is possible to accurately determine whether or not the object is the carriage even when the carriage operation is carried out in a dark place, for example.

A carriage detection system according to a twelfth invention comprises the carriage detection device according to any one of the first to eleventh inventions, an illumination device for irradiating an object with electromagnetic waves, and an electromagnetic wave emitted from the illumination device. and a light receiving portion for detecting the amount of reflected electromagnetic waves.
With this configuration, the light-receiving unit detects the reflection from the object of the electromagnetic wave emitted from the lighting device, so that distance information to the object can be calculated (acquired) according to the amount of reflection. Therefore, it is possible to construct a system for accurately determining whether or not the object is a carriage according to the calculated distance information.

A carriage detection system according to a thirteenth aspect of the invention is the carriage detection system according to the twelfth aspect of the invention, wherein exposure time for detecting the amount of electromagnetic waves emitted from the illumination device and the amount of reflection of the electromagnetic waves by the light receiving unit is A regulating control is further provided.
Accordingly, by adjusting the exposure time by the control unit, it is possible to irradiate the electromagnetic wave and receive the reflected electromagnetic wave with an appropriate exposure time according to the distance to the object.
Further, by adjusting the exposure time appropriately to obtain binarized data, it is possible to accurately determine whether or not the object is the carriage using the distance information.

A carriage detection system according to a fourteenth invention is the carriage detection system according to the thirteenth invention, wherein the control unit adjusts the exposure time according to the distance to the object.
As a result, the control unit shortens the exposure time when the distance to the object is short, and lengthens the exposure time when the distance to the object is long. It is possible to irradiate the electromagnetic wave and receive the reflected electromagnetic wave with an appropriate exposure time.

A carriage detection method according to a fifteenth aspect of the present invention is a carriage detection method for detecting a carriage that is conveyed by a conveying device with a load placed thereon, comprising a distance information acquisition step and a determination step. there is In the distance information acquisition step, distance information to the object is acquired according to the amount of reflection of the electromagnetic waves irradiated from the lighting device to the object. In the determination step, it is determined whether or not the object is a carriage based on the distance information to the object acquired in the distance information acquisition step.

Here, for example, it is obtained from a TOF (Time of Flight) sensor that receives the reflected light of light emitted toward the object from an LED (Light Emitting Diode) as a light source and measures the distance to the measurement object. Using distance information to the object, it is determined whether the object is a carriage.
Here, the carriage to be judged has a receiving part such as a hole or a concave part into which an arm part of a carriage such as a forklift is inserted, regardless of the material such as wood or resin.

Electromagnetic waves emitted from lighting equipment include, for example, light in a broad sense (ultraviolet light, visible light, infrared light), γ (gamma) rays with shorter wavelengths than light, X-rays, microwaves with longer wavelengths than light, and broadcasting Any wave can be used as long as its reflection is attenuated by the square of the distance, including radio waves (short, medium, and long waves), ultrasonic waves, elastic waves, quantum waves, and the like.
In the distance information acquisition step, the distance information may be calculated by detecting the reflection of the electromagnetic wave, or the distance information may be acquired from a distance sensor or the like provided as an external device, for example.
As a result, for example, even if a black pattern or the like is written on the side surface of an object placed on the floor, the characteristics of the transport table transported by the transport device (for example, the arm part of the transport device, etc. can be inserted) The presence or absence of a receiving portion such as a hole or recess) can be detected using distance information.
As a result, it is possible to accurately determine whether or not the detected object is the carriage.

A carriage detection program according to a sixteenth aspect of the present invention is a carriage detection program for detecting a carriage that is conveyed by a conveying device with a load on it, comprising a distance information acquisition step and a determination step. cause the computer to execute the carriage detection method. In the distance information acquisition step, distance information to the object is acquired according to the amount of reflection of the electromagnetic waves irradiated from the lighting device to the object. In the determination step, it is determined whether or not the object is a carriage based on the distance information to the object acquired in the distance information acquisition step.

Here, for example, it is obtained from a TOF (Time of Flight) sensor that receives the reflected light of light emitted toward the object from an LED (Light Emitting Diode) as a light source and measures the distance to the measurement object. Using distance information to the object, it is determined whether the object is a carriage.
Here, the carriage to be judged has a receiving part such as a hole or a concave part into which an arm part of a carriage such as a forklift is inserted, regardless of the material such as wood or resin.

Electromagnetic waves emitted from lighting equipment include, for example, light in a broad sense (ultraviolet light, visible light, infrared light), γ (gamma) rays with shorter wavelengths than light, X-rays, microwaves with longer wavelengths than light, and broadcasting Any wave can be used as long as its reflection is attenuated by the square of the distance, including radio waves (short, medium, and long waves), ultrasonic waves, elastic waves, quantum waves, and the like.
In the distance information acquisition step, the distance information may be calculated by detecting the reflection of the electromagnetic wave, or the distance information may be acquired from a distance sensor or the like provided as an external device, for example.

As a result, for example, even if a black pattern or the like is written on the side surface of an object placed on the floor, the characteristics of the transport table transported by the transport device (for example, the arm part of the transport device, etc. can be inserted) The presence or absence of a receiving portion such as a hole or recess) can be detected using distance information.
As a result, it is possible to accurately determine whether or not the detected object is the carriage.

(Effect of the invention)
According to the carriage detection device of the present invention, it is possible to accurately determine whether or not the detected object is the carriage.

1 is a diagram showing a forklift equipped with a transport state detection device according to an embodiment of the present invention and a transport table to be transported; FIG. 2(a) is a perspective view showing a carrier that is carried by the forklift in FIG. 1; FIG. (b) is a perspective view showing another example of the carrier; FIG. 2 is a control block diagram of the forklift of FIG. 1 and the transfer state detection device mounted on the forklift. FIG. 2 is a view for explaining the principle of calculating the distance to an object by the TOF method using the transport state detection device of FIG. 1; FIG. 4 is a diagram showing a carrier table stored in a storage unit included in the carrier state detection device of FIG. 3; 4 is a flow chart showing the flow of processing of a carriage detection method by the conveyance state detection apparatus of FIG. 1; 4 is a flow chart showing the flow of processing of a carriage detection method by the conveyance state detection apparatus of FIG. 1; (a), (b), (c) is a schematic diagram explaining the detection process of a conveyance stand. 11A is a perspective view showing a plane defined in the flowchart of FIG. 10 and an object without depth information (hole) on the plane; FIG. 11B is a perspective view showing a plane defined in the flowchart of FIG. 10 and an object having depth information (holes) on the plane; FIG. 2 is a flow chart showing the flow of processing of a transport state detection method by the transport state detection device of FIG. 1; (a) is a front view showing the size of the detection surface of the transport state detection device in the x-axis direction. 4B is a plan view showing the detection direction of the transport state detection unit; FIG. (c) is a plan view showing the positional relationship between the detection direction of the transport state detection device and the transport table. FIG. 2 is a plan view showing the positional relationship between a carrier and a load placed thereon; FIG. 4 is a conceptual diagram for explaining detection of a carriage in a darkroom;

A forklift (conveying device) 20 equipped with a conveying state detecting device (conveying platform detecting device, conveying state detecting device) 10 according to one embodiment of the present invention will be described below with reference to FIGS. be.
(1) Forklift 20
A forklift (conveyor) 20 is a device used to convey a carrier 30 on which a load 31 is placed to a desired position, as shown in FIG. , 22b, a drive unit 23, an arm unit 24, a transport control unit 25 (see FIG. 3), a traveling actuator 26 (see FIG. 3), a braking device 27 (see FIG. 3), and an elevating actuator 28 (see FIG. 3). 3).

The forklift 20 of this embodiment is operated by a driver. It assists the driving operation by the driver.
The forklift 20 can be automatically operated without the driver's operation. It may be used as an automatic transport device for driving.

The vehicle body portion 21 accommodates a driving source such as an engine and a motor inside, and a driving portion 23 for vertically driving an arm portion (fork) 24 is provided in front thereof.
Two wheels 22a and 22b are provided on the front and rear sides of the vehicle body 21. The front wheel 22a is rotationally driven by the transport control unit 25, and the rear wheel 22b is steered by operating the steering wheel. , can run and turn.

The drive section 23 is attached to the front of the vehicle body section 21 and includes elevating actuators such as a mast, sprockets, chains, and hydraulic cylinders. The drive unit 23 drives the arm unit 24 in the vertical direction or the tilt direction according to the operation of an operation lever (not shown) by the driver. As a result, the carriage 30 and the like supported by the arm portion 24 can be lifted and conveyed.

The arm portion 24 is driven vertically by the driving portion 23 and is two claw-like members extending forward, and is inserted into a hole (receiving portion) 30b or the like provided in the carriage 30 .
The transportation control unit 25 is a controller that controls transportation of the forklift 20, and as shown in FIG. 3, has a traveling control unit 25a and an arm control unit 25b.

The travel control unit 25a controls the output of a driving source such as an engine or a motor so that the vehicle speed of the forklift 20 becomes a target speed.
The arm control section 25b controls the elevation of the arm section 24 according to the amount of operation of an operating lever (not shown) installed in the driver's seat provided in the vehicle body section 21 . Further, the arm control unit 25b automatically adjusts the distance between the two arms 24 in accordance with the detected position of the hole 30b of the carriage 30 according to the detection result of the carriage 30, which will be described later. may be controlled.

The travel actuator 26 is configured to include a drive source such as an engine or a motor, and drive transmission means for transmitting the output of the drive source to the drive-side wheels 22a.
The braking device 27 is provided to reduce the vehicle speed of the running forklift 20 or to stop it. The braking device 27 applies braking force corresponding to the amount of operation to the brake pedal provided in the driver's seat to the wheels 22a.
The elevation actuator 28 is provided in the drive section 23 and includes, for example, hydraulic cylinders such as lift cylinders and tilt cylinders. The hydraulic cylinder changes the angle of the arm portion 24 in the tilt direction or moves the position of the arm portion 24 up and down according to the amount of operation of an operation lever (not shown) installed in the driver's seat.

(2) Conveyor table 30
Here, the carrier 30 carried by the forklift 20 of this embodiment will be described with reference to FIGS. 2(a) and 2(b).

The carriage 30 is a pallet made of resin, and as shown in FIG.
The main body 30a is, for example, a pallet made of reusable resin such as PP (polypropylene), and has an upper surface on which the load 31 is placed, four side surfaces, and a bottom surface.
Four side surfaces of the main body portion 30a are formed with holes 30b into which the arm portions 24 of the forklift 20 can be inserted.

Two holes (receiving portions) 30b are provided on each of the four side surfaces of the body portion 30a, and the two arm portions 24 of the forklift 20 are inserted therein.
For example, the holes 30b into which the arm portions 24 of the forklift 20 are inserted may be provided on all four side surfaces of the main body portion 30a, or may be provided only on a set of two opposing side surfaces. , or may be provided on only one surface.
As a type of the carrier 30 carried by the forklift 20, as shown in FIG. It may be the carriage 130 .
In this case, instead of being inserted into the hole 30b, the arm portion 24 of the forklift 20 is inserted between the floor surface FL and the upper surface forming the recess 130b, and is conveyed so as to support the recess 130b from below. Platform 130 can be lifted.

(3) Conveyance state detector 10
As shown in FIG. 1, the transport state detection device 10 of the present embodiment is attached to the upper part of the drive unit 23, detects the transport table 30 transported by the forklift 20, and The state (position, range, height, balance, etc.) of the loaded cargo 31 is detected.

As shown in FIG. 3, the transport state detection device 10 includes an illumination unit (illumination device) 11, a light receiving unit 12, a control unit (determination unit) 13, a distance measurement unit 14, a storage unit 15, and a transport table. An information acquisition unit 16 and a load state acquisition unit (determination unit) 17 are provided.
The illumination unit (illumination device) 11 has, for example, an LED, and irradiates an object such as the carrier 30 or the load 31 with light L1 having a desired wavelength. The illumination unit 11 is provided with a projection lens (not shown) that guides the light L1 emitted from the LED toward the object.

The light receiving unit 12 includes, for example, a light receiving lens and an imaging device.
The light-receiving lens is provided to receive reflected light emitted from the illumination unit 11 to the object and reflected by the object, and guide the light to the imaging element.
The imaging element has a plurality of pixels, and each of the plurality of pixels receives the reflected light received by the light receiving lens, and transmits an electric signal photoelectrically converted to the control unit 13 . An electric signal corresponding to the amount of reflected light received by the image sensor is used by the control unit 13 to calculate distance information.

The control unit (determining unit) 13 reads various control programs stored in the storage unit 15 and controls the lighting unit 11 that irradiates light onto the object. More specifically, the control unit 13 controls the illumination unit 11 so as to irradiate the optimum light according to the distance to the object irradiated with the light, the properties of the object such as the shape, color, and the like. In addition, the control unit 13 determines whether or not the object is the carriage 30 based on the characteristics of the object, which will be described later. It is determined whether or not the loading state of the cargo 31 is appropriate.

In addition, the control unit 13 adjusts the exposure time of the light receiving unit 12 for detecting the amount of reflected light of the illumination unit 11 and the light emitted from the illumination unit 11, for example, according to the distance to the object. . Alternatively, the control unit 13 adjusts the exposure times of the illumination unit 11 and the light receiving unit 12 depending on whether or not binarized data (to be described later) can be acquired.
Specifically, the control unit 13 adjusts the exposure time to be short when the distance to the object is short, and adjusts the exposure time to be long when the distance to the object is long. do.

The detection (determination) of the carriage 30 and the detection (determination) of the transport state by the control unit 13 will be described later in detail.
The distance measurement unit 14 calculates distance information to the object for each pixel based on the electrical signal corresponding to each pixel received from the image sensor included in the light receiving unit 12 .
Calculation of distance information to an object by the distance measuring unit 14 of this embodiment will be described below with reference to FIG.

That is, in the present embodiment, using a so-called TOF (Time of Flight) method, the distance measurement unit 14 detects an AM-modulated constant frequency projection wave such as a sine wave or a square wave emitted from the illumination unit 11, The distance to the object is calculated based on the phase difference Φ (see FIG. 4) between the light received by the imaging device included in the light receiving unit 12 and the received wave.
Here, the phase difference Φ is represented by the following relational expression (1).

Φ=atan(y/x) (1)
(x=a2-a0, y=a3-a1, a0-a3 are the amplitudes at the points where the received wave was sampled four times at intervals of 90 degrees)
A conversion formula from the phase difference Φ to the distance D is given by the following relational expression (2).
D=(c/(2×f _LED ))×(Φ/2π)+D _OFFSET (2)
(c is the speed of light (≈3×10 ⁸ m/s), f _LED is the modulation frequency of the LED projection wave, and D _OFFSET is the distance offset.)
As a result, the distance measurement unit 14 receives the reflected light of the light emitted from the illumination unit 11 and compares the phase difference, thereby easily calculating the distance to the object using the speed of light c. be able to.

The storage unit 15 stores various programs for controlling the operation of the transport state detection device 10, and also registers information about the characteristics of the transport table 30 detected as the transport table 30 (for example, the size, the position of the hole 30b, etc.). A carriage database (DB) 15a is stored.
The carriage DB 15a stores a carriage table (see FIG. 5) including information such as the external dimensions of the object determined as the carriage 30 and the type of receiving portion (hole or recess). Thus, the carriage DB 15a is referred to when determining which type of carriage the detected object is.

The carriage information acquisition unit 16 acquires object information necessary for determining whether or not the object, which will be described later, is the carriage 30 . Specifically, the carriage information acquisition unit 16 acquires information such as the size (width, height, etc.) of an object assumed to be the carriage 30, the presence or absence of a receiving part (hole, recess, etc.), and the position thereof. get.
The load state acquisition unit 17 detects the state of the load 31 placed on the object determined to be the carrier 30 . As shown in FIG. 3, the load state acquisition unit 17 has a position information acquisition unit 17a, a posture information acquisition unit 17b, a shape information acquisition unit 17c, and a height information acquisition unit 17d.

The position information acquisition unit 17 a detects the position of the load 31 on the object determined to be the carrier 30 .
The orientation information acquisition unit 17b detects the orientation of the load 31 with respect to the object determined to be the carriage 30 .
The shape information acquisition unit 17c detects information on the shape (external shape, etc.) of the load 31 on the object determined to be the carrier 30 .
The height information acquisition unit 17d detects height information of the load 31 on the object determined to be the carriage 30 .

<Conveyor detection method>
In the carriage detection method of the present embodiment, first, according to the flowcharts shown in FIGS. Determine whether or not there is

Here, zs is the mounting position of the light receiving unit 12 (imaging device) relative to the floor FL (z=0), zθ is the mounting angle of the light receiving unit 12 (imaging device) with respect to the floor FL, and the transport state detection device 10 3D shape information (outer shape Pv, plane Ps, depth information Pp) of the object (object P) assumed to be the carriage 30 detected by , and 3D shape information (outer shape Pv, receiving part type Ps), 3D shape information of the target (Q) assumed to be the cargo 31 (outer shape Qv, plane Qs, features Qp such as unevenness), initially set exposure time Inti of the light receiving unit 12 (imaging device), received light The plane Sy plane of the portion 12 is defined as the center point S (Sx/2) of the light receiving portion 12 (see FIGS. 8A and 8B).

It should be noted that the x-axis is the direction perpendicular to the traveling direction (horizontal direction), the y-axis is the longitudinal direction (the traveling direction of the forklift 20), and the z-axis is the height direction (vertical direction) from the floor FL.
As shown in FIG. 6, in step S11, the exposure times of the illumination unit 11 (illumination device) and the light receiving unit 12 (imaging device) of the transport state detection device 10 are set to initial set values.
Next, in step S12, using the distance information measured (acquired) by the distance measuring unit 14 using the TOF method described above, a three-dimensional (3D ) information is obtained.

Here, a case where light emitted from the illumination unit 11 of the transport state detection device 10 is emitted forward of the forklift 20 will be described.
Next, in step S13, the floor FL (z=0) is defined from the three-dimensional information acquired in step S12, and the mounting position zs and mounting angle zθ of the light receiving unit 12 (imaging device).

Note that the range of the three-dimensional information acquired here is determined according to the performance (angle of view, etc.) of the imaging element of the light receiving unit 12 .
Next, in step S14, an object P that satisfies z>0 with respect to the floor FL (z=0), that is, an object that is taller than the floor FL is detected.
Next, in step S15, binarized data is acquired based on the information PX of the object P (distance or brightness information).

It should be noted that the binary data to be acquired is preferably acquired based on brightness information rather than distance information from the viewpoint that it can be stably acquired regardless of resolution.
Next, in step S16, it is determined whether or not the binarized data has been properly acquired, that is, whether or not the edge of the object P (and object Q) has been detected. Here, if the binarized data is properly acquired, the process proceeds to step S17. On the other hand, if the binarized data is not properly acquired, the process proceeds to step S20 to adjust the exposure time Inti of the illumination unit 11 (illumination device) and the light receiving unit 12 (imaging device).

Next, in step S17, Pvx (outer shape of object P) is defined using the binarized data because it was determined in step S16 that the binarized data was properly acquired.
Next, in step S18, a plane Psx (surface information of the object P) within the range of the outer shape Pvx of the object P is defined from the distance information corresponding to each pixel of the image sensor acquired by the TOF method.

In addition, in this embodiment, the side surface portion of the object P where the receiving portion such as the hole 30b may be formed is defined as the plane Psx.
Next, in step S19, it is determined whether or not the plane Psx has been acquired. If the plane Psx has been acquired, the process proceeds to the flowchart shown in FIG. device) and the light receiving unit 12 (imaging device) are adjusted, and the process returns to step S18 again.

Here, in step S20, since it was determined in step S16 that the binarized data was not properly acquired, the exposure time Inti is adjusted based on the brightness information acquired by the light receiving unit 12 (imaging device). .
For example, when the brightness of the information PX of the object P is high, saturation may occur, so the exposure time is adjusted to be shorter. On the other hand, if the brightness of the information PX of the object P is low, there is a possibility that the image pickup element cannot detect a sufficient amount of light, so the exposure time is adjusted to be longer.

Subsequently, as shown in FIG. 7, in step S21, a plane Psz having the same z-coordinate as the base Psx of the carriage 30 is defined, and a space formed by a plane including the plane Psx and a plane including the plane Psz is defined as a side. Z-coordinate information is obtained while scanning from Px in the y-axis direction (see FIGS. 8B and 8C).
Next, in step S22, it is determined whether or not the z-axis information (height) is constant in the x-axis direction or the y-axis direction. Here, if it is determined that the z-axis information (height) is constant as shown in FIG. ) is not constant, the process proceeds to step S28.

Next, in step S23, since it was determined in step S22 that the z-axis information (height) on the base Px is constant, the object P is not irregularly shaped, and there is a possibility that it is the carriage 30 on which the load 31 is not placed. is tentatively determined as a certain object.
Next, in step S24, depth information Ppx of the object P is defined from the plane Psx.
At this time, the exposure time may be adjusted, or the forklift 20 may be moved, so that the depth information Ppx representing holes and recesses can be easily obtained.

Next, in step S25, it is determined from the depth information Ppx whether or not there is a depth within the plane Psx, that is, whether or not there is a receiving portion such as the hole 30b within the plane Psx.
Here, in the transport state detection apparatus 10 of the present embodiment, the TOF method is employed as described above, and the distance information corresponding to each pixel of the imaging device is measured (obtained) by the distance measuring section 14 . For this reason, as shown in FIG. 9(a), an object P having a black pattern on the side surface and an object P having a hole 30b having depth information formed in the side surface as shown in FIG. 9(b). can be discerned based on the obtained distance information.

Here, if it is determined that the plane Psx has a depth, that is, a receiving portion such as a hole 30b (see FIG. 9B), the process proceeds to step S26, and there is no depth (receiving portion such as a hole 30b) (see FIG. 9B). 9(b)), the process proceeds to step S27.
Next, in step S26, since it was determined in step S25 that the depth (hole 30b) exists within the plane Psx, it is determined that the object P is the carriage 30 having the receiving portion (hole 30b) based on the depth information Ppx. . Then, a carriage table (see FIG. 5) is created in which information such as the outer shape, size, type of receiving portion (hole, recess), etc. of the carriage 30 is registered.

Next, in step S27, since it was determined in step S25 that there is no depth (the hole 30b) (they are substantially flat), the object P does not have a receiving portion for inserting the arm portion 24 of the forklift 20, and is transported. It is determined that it is not the platform 30, and the process is terminated.
On the other hand, in step S28, since it was determined in step S22 that the z-axis information (height) is not constant in the x-axis direction or the y-axis direction, the object P is placed on the carriage 30 on which the load 31 is placed or the carriage It is tentatively determined to be an odd-shaped object that is not.

Next, in step S29, the object P tentatively determined in step S28 is matched with the carriage 30 registered in the carriage table by referring to the carriage DB 15a.
That is, in step S29, a part of the object P (particularly, the lower part) is matched to determine whether or not the outer shape, size, hole position, etc. of the carriage 30 already registered in the carriage table match.

Next, in step S30, it is determined whether or not the object P includes the carriage 30 according to whether or not part of the object P matches the registered carriage 30 as a result of matching in step S29. be done.
Here, if it is determined that it matches the registered carriage 30, the process proceeds to step S26, the information of the carriage 30 is registered in the carriage table, and the process ends.
On the other hand, if it is determined that part of the object P does not match the registered carriage 30 as a result of matching, it is determined that the object P is not the carriage 30, and the process ends.

<Conveyance state detection method>
In the transport state detection method of this embodiment, according to the flowchart shown in FIG. 10, the appropriateness of the state of the load 31 placed on the transport table 30 detected by the above-described transport table detection process is determined.

First, regarding the object P determined to be the carriage 30 in step S30 and the object Q placed on its upper surface as the load 31, from the outer shape Pvx and the plane Psx of the object P, the front surface of the object P as seen from the light receiving unit 12 Py is defined, and the length of the front surface Py in the x-axis direction is Px. The plane of the object Q having the y coordinate closest to the front face Py of the object P is defined as a plane Qy, and the length of the plane Qy in the x-axis direction is defined as Qx (see FIG. 8A).

First, in step S31, it is determined whether or not the three-dimensional shape information (outer shape Qv and plane Qs) of the object Q assumed to be the cargo 31 distinguished from the object P determined to be the carriage 30 has been acquired.
Here, if the outer shape Qv and the plane Qs have been acquired, the process proceeds to step S32. The adjustment of the exposure time Inti is repeated until the time Inti is adjusted, the process returns to step S31, and the outline Qv and the plane Qs are obtained.

Next, in step S32, depth information Qpx of the object Q is defined from the plane Qy of the object Q placed on the upper surface of the object P detected as the carrier 30. FIG.
At this time, adjustment of the exposure time of the illumination unit 11 (illumination device) and the light receiving unit 12, movement of the forklift 20, and the like may be performed so that the depth information of the object Q can be easily acquired.
Thus, similarly to the object P, the depth information of the object Q can be obtained by using the distance information obtained by the TOF method and obtained in each pixel of the image sensor.

Next, in step S33, in order to detect how the object Q is placed on the object P, the base Px of the plane Psx of the object P and the base Qx of the plane Qy of the object Q are calculated (Fig. 8(a)).
Here, as described above, the base Px and the base Qx are the object P determined to be the carriage 30 and the load 31 placed on its upper surface using the information of the carriage 30 registered in the carriage table. is calculated after separating the object Q assumed to be .

Then, the front face Py of the object P is defined from the outline Pvx and the plane Psx of the object P, and the length of the base Px of the front face Py in the x-axis direction is calculated.
If the plane of the object Q having the y coordinate closest to the front face Py of the object P is defined as a plane Qy, the length Qx of the plane Qy in the x-axis direction is calculated.
The height Qz of the object Q is the maximum size of the plane Qy in the z-axis direction.

Next, in step S34, the base Px of the object P and the base Qx of the object Q calculated in step S33 are compared, and how the object Q is positioned on the object P is detected.
Specifically, for example, whether or not the object Q protrudes from the upper surface of the object P is detected using the x-axis information (Px) of the object P and the x-axis information (Qx) of the object Q.
Next, in step S35, in order to determine the state of the load 31 placed on the upper surface of the carriage 30, first, the state of the object P detected as the carriage 30 facing the light receiving unit 12 (imaging device) is directly facing. (Angle θ1) is confirmed.

Here, assuming that the angle θ1 is the plane Sy of the light receiving unit 12 and its length Sx in the x-axis direction as shown in FIGS. is calculated as an angle indicating the position (orientation) of the front face Py of the object P detected as .
Specifically, the angle θ1 is calculated using the distance between the light receiving unit 12 and the object P (distance in the y-axis direction) and the facing relationship between the light receiving unit 12 and the object P, as shown in FIG. , a point U is placed on a line of y-coordinate=yp parallel to points T and Sx on the extension of the base Px of the object P, the following relational expression (1) is used.

PT PU=|PT||PU|cos θ1 (1) (bold letters are vectors)
From this relational expression (1), the angle θ1 of the object P (conveyor 30) with respect to the light receiving section 12 can be calculated.
Next, in step S36, an angle θ2 shown in FIG. 12 is calculated in order to detect how the object Q (cargo 31) is placed on the upper surface of the object P (carriage 30).

Specifically, the center point Px/2 of the base Px of the front face Py of the object P, the center point Qx/2 of the base Qx of the plane Qy of the object Q, the point P(x, y), the point Q(x, y ), and the intersection point of the center line of the object P passing through the point P and the center line of the object Q passing through the point Q is the point R. ).
RP RQ=|RP||RQ|cos θ2 (2) (bold letters are vectors)
By calculating the angle θ2 of the object Q (load 31) placed on the upper surface of the object P (transport table 30) from this relational expression (2), the load 31 is placed on the transport table 30 within an appropriate range, It can be determined whether it is placed in the orientation and position.
As a result, for example, when it is determined that the state of the cargo 31 on the carrier 30 is not suitable for transportation, it is possible to stop the transportation and correct the position of the cargo 31, for example.

<Main feature 1>
The conveying state detection device 10 of this embodiment is a device for detecting a conveying table 30 conveyed by a forklift 20 with a load 31 placed thereon, and includes a distance measuring section 14 and a control section 13. . The distance measurement unit 14 measures the distance to the object according to the amount of reflection of the light emitted from the illumination unit 11 to the object. The control unit 13 determines whether or not the object is the carriage 30 based on the distance to the object measured by the distance measuring unit 14 .

As a result, for example, even if a black pattern or the like is written on the side surface of the object placed on the floor FL, the characteristics of the carrier 30 conveyed by the forklift 20 (for example, the arm portion 24 of the forklift 20 is inserted) It is possible to detect the presence or absence of a receiving portion such as a hole 30b, etc., to be inserted using the distance information.
As a result, it is possible to accurately determine whether or not the detected object is the 30 transports.

<Main feature 2>
The conveying state detection device 10 of the present embodiment is a device for detecting the state of the load 31 on the carrier 30 which is transported by the forklift 20 with the load 31 placed thereon. and The distance measuring unit 14 acquires information about the distance to the object according to the amount of reflection of the light emitted from the illumination unit 11 to the object. The control unit 13 determines the state of the load 31 on the carriage 30 based on the distance information to the object acquired by the distance measurement unit 14 .

As a result, for example, the state of the load 31 on the carriage 30, such as the position, orientation, size, and deviation of the load 31 (object Q) on the object P detected as the carriage 30, can be determined using the distance information. can be easily detected.
As a result, it is possible to accurately determine whether the detected state of the cargo 31 on the carrier 30 is suitable for transportation.

[Other embodiments]
Although one embodiment of the present invention has been described above, the present invention is not limited to the above-described embodiment, and various modifications are possible without departing from the gist of the invention.

(A)
In the above-described embodiment, examples of realizing the present invention have been described as the carriage detection device and the carriage detection method. However, the present invention is not limited to this.
For example, the present invention may be implemented as a program that causes a computer to execute the carriage detection method described above.
This program is stored in the memory (storage unit) mounted on the carriage detection device, and the CPU reads the carriage detection program stored in the memory and causes the hardware to execute each step. More specifically, the same effect as described above can be obtained by causing the CPU to read the carriage detection program and execute the above-described distance information acquisition step and determination step.
Further, the present invention may be implemented as a recording medium storing a carriage detection program.

(B)
In the above-described embodiment, an example in which light in a broad sense is used as the electromagnetic wave with which the object is irradiated from the illumination unit 11 has been described. However, the present invention is not limited to this.
For example, when infrared light IR is used as the light emitted from the lighting device to the object, as shown in FIG. By detecting the reflection of the infrared light IR and obtaining distance information to the object, it is possible to detect the carriage 30 and the state of the load 31 on the carriage 30, which is the same effect as described above. can be obtained.

(C)
In the above-described embodiment, an example in which the transport state detection device (transport platform detection device) 10 is mounted on a forklift (transport device) 20 has been described. However, the present invention is not limited to this.
For example, a carrier detection device may be used as a device installed separately from the carrier device.
Alternatively, the transport state detection device (transport platform detection device) of the present invention may be installed in a controller of a transport device such as a forklift.

(D)
In the above-described embodiment, an example has been described in which whether or not the detected object P is the carriage 30 is determined based on the presence or absence of the receiving portion (hole 30b). However, the present invention is not limited to this.
For example, in addition to the presence or absence of the receiving portion, other factors such as the size and position of the receiving portion may be added to determine whether or not the object is the carriage.

(E)
In the above-described embodiment, an example has been described in which distance information is calculated by detecting the amount of reflection of the light L1 with which the object is irradiated. However, the present invention is not limited to this.
For example, information on the distance to the object calculated by a TOF sensor provided outside the apparatus may be obtained to detect the carriage and the state of conveyance.

(F)
In the above embodiment, an example in which light in a broad sense is used as the electromagnetic wave with which the object is irradiated from the illumination unit 11 has been described. However, the present invention is not limited to this.
For example, the electromagnetic waves irradiated from the irradiation device to the target object include, in addition to broadly defined light (ultraviolet light and visible light), γ (gamma) rays with shorter wavelengths than light, X-rays, and Other electromagnetic waves such as microwaves, radio waves for broadcasting (short, medium, and long waves), ultrasonic waves, elastic waves, and quantum waves may be used.

(G)
In the above-described embodiment, an example in which the forklift 20 is used as the transport device on which the transport state detection device (transport platform detection device) 10 is mounted has been described. However, the present invention is not limited to this.

For example, the carriage detection device of the present invention may be mounted on other transportation devices such as transportation robots such as AGVs (Automatic Guided Vehicles) and AMRs (Autonomous Mobile Robots).
Further, the carriage detection device of the present invention may be mounted on a non-traveling conveying device in addition to being mounted on a self-propelled conveying device.

(H)
In the above-described embodiment, as shown in FIG. 3, the carriage database includes a carriage table (see FIG. 5) in which information about the characteristics (size, shape, etc.) of the carriage 30 is registered in the conveyance state detection device 10. 15a has been described. However, the present invention is not limited to this.
For example, other storage means such as a server provided outside may be used as the storage unit for storing the carriage database.

(I)
In the above-described embodiment, an example in which the conveying table 30 made of resin is detected by the conveying state detection device 10 of the present invention has been described. However, the present invention is not limited to this.
For example, the material of the carriage is not limited to resin, and may be wood, metal, rubber, or other material other than resin.

(J)
In the above-described embodiment, an example has been described in which reflection of light emitted toward the front of a conveying device such as the forklift 20 is detected to detect the conveying table 30 and the like in front of the conveying device. However, the present invention is not limited to this.

For example, a configuration may be adopted in which the reflection of light irradiated toward the rear or side of the transport device is detected to detect the transport table or the like behind or to the side of the transport device.

INDUSTRIAL APPLICABILITY The carriage detection device of the present invention has the effect of being able to accurately determine whether or not a detected object is a carriage, so it can be widely applied to various devices that detect carriages. is.

10 Conveyance state detection device (Conveyance table detection device, Conveyance state detection device)
11 lighting unit (lighting device)
12 light receiving unit 13 control unit (determining unit)
14 distance measurement unit (distance information acquisition unit)
15 storage unit 15a carriage database (carriage DB)
16 carriage information acquisition unit 17 load state acquisition unit 17a position information acquisition unit 17b posture information acquisition unit 17c shape information acquisition unit 17d height information acquisition unit 20 forklift (conveyor)
21 Vehicle body parts 22a, 22b Wheels 23 Driving part 24 Arm part 25 Transfer control part 25a Traveling control part 25b Arm control part 26 Traveling actuator 27 Braking device 28 Elevating actuator 30 Carrier 30a Body part 30b Hole (receiving part)
31 Cargo 130 Conveyor 130a Main body 130b Recess (receiving part)
FL Floor surface IR Infrared rays (electromagnetic waves)
L1 light (electromagnetic waves)
P object Q object

Claims (16)

1. A carriage detection device for detecting a carriage conveyed by a conveying device with a load on it,
   a distance information acquisition unit that acquires distance information to the object according to the amount of reflection of electromagnetic waves irradiated from the lighting device to the object;
   a determination unit that determines whether the object is a carriage based on the distance information to the object acquired by the distance information acquisition unit;
   A carriage detection device comprising a
2. The carrier has a receiving portion into which an arm member of the carrier is inserted,
   Using the distance information, the determination unit determines whether or not the object is the carriage according to at least one of presence/absence, size, and position of the receiving unit.
   The carriage detection device according to claim 1.
3. Using the distance information, the determination unit determines whether the object is the single carrier or the carrier on which the load is placed, according to at least one of the presence/absence, size, and position of the receiving unit. , determine that it is any of the objects other than the carriage,
   The carriage detection device according to claim 2.
4. The determination unit uses the distance information to detect a floor surface on which the object is placed, and detects an object having a height from the floor surface as a candidate for the carriage.
   The carriage detection device according to any one of claims 1 to 3.
5. The determining unit sets an outer shape of the object detected as the candidate for the carriage based on the distance information.
   The carriage detection device according to claim 4.
6. The determination unit sets the outer shape using binarized data obtained based on the distance information or the brightness information of the image of the object.
   The carriage detection device according to claim 5.
7. When the binarized data cannot be obtained in the determination unit, the exposure time for irradiating and receiving the electromagnetic wave emitted from the lighting device is adjusted.
   The carriage detection device according to claim 5 or 6.
8. The determination unit sets a detection surface assumed to be formed with a receiving portion into which an arm member of the transport device is inserted, based on the set outer shape.
   The carriage detection device according to any one of claims 5 to 7.
9. The determination unit determines whether or not it is the carriage according to depth information of the receiving unit on the detection surface.
   The carriage detection device according to claim 8 .
10. further comprising a storage unit that stores detection data of the carriage determined by the determination unit to be the carriage,
    The carriage detection device according to any one of claims 1 to 9.
11. the electromagnetic waves are infrared rays;
    The carriage detection device according to any one of claims 1 to 10.
12. a carriage detection device according to any one of claims 1 to 11;
    a lighting device that irradiates the electromagnetic wave to the object;
    a light receiving unit that detects the amount of reflection of the electromagnetic wave emitted from the lighting device;
    carriage detection system.
13. A control unit that adjusts the irradiation amount of the electromagnetic wave from the lighting device and the exposure time for the light receiving unit to detect the reflection amount of the electromagnetic wave,
    13. The carrier detection system of claim 12.
14. The control unit adjusts the exposure time according to the distance to the object.
    14. The carrier detection system of claim 13.
15. A carrier detection method for detecting a carrier transported by a carrier device with a load on it, comprising:
    a distance information acquisition step of acquiring distance information to the object according to the amount of reflection of electromagnetic waves irradiated from the lighting device to the object;
    a determining step of determining whether or not the object is a carriage based on the distance information to the object acquired in the distance information acquiring step;
    A carrier detection method comprising:
16. A carrier detection program for detecting a carrier transported by a carrier device with a load on it,
    a distance information acquisition step of acquiring distance information to the object according to the amount of reflection of electromagnetic waves irradiated from the lighting device to the object;
    a determining step of determining whether or not the object is a carriage based on the distance information to the object acquired in the distance information acquiring step;
    A carriage detection program for causing a computer to execute a carriage detection method comprising:

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