JPH01197809A - Guidance mark for unmanned vehicle - Google Patents

Abstract

PURPOSE:To constitute the title guidance mark so that the center position of the mark and the contents of a code can always be read exactly from an direction irrespective of an inclination of the unmanned vehicle by forming an external form of the mark to a circle, and also, putting a circular code which is the same concentric circle as the mark and can be discriminated from other mark to the inside of the mark. CONSTITUTION:A mark 5 consists of a circle and provided with a first black sheet band 30 whose whole periphery consists of a black part, a first white sheet band 31 consisting of a white part of the inside of the first black sheet band and a code sheet band 32 of the inside of the first white sheet band 31, from its outside periphery. Also, this mark is constituted by providing a second black sheet band 33 consisting of a black part of the inside of the code sheet band 32, a second white sheet band 34 consisting of a white part of the inside of the second black sheet band 33, and the center black sheet band 35 consisting of a black part of the inside of the second white sheet band 34. In such a way, the center position of the mark and the contents of the code can always be read exactly from any direction irrespective of an inclination of an unmanned vehicle.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a guidance device for an unmanned vehicle, and more specifically,
The present invention relates to a device that guides an unmanned vehicle to travel along a desired course based on image information.

[Background of the invention]

The guidance method of the above-mentioned unmanned vehicle (hereinafter simply referred to as unmanned vehicle) is to lay a guidance wire such as an electromagnetic induction wire or optical tape on the floor during the course of the vehicle, and to detect the guidance by detecting the guidance installed on the unmanned vehicle. Many fixed-route guidance systems for unmanned vehicles, which detect the position of unmanned vehicles and control the steering of the unmanned vehicles so that they follow the guide line, are currently in practical use.

However, the fixed route guidance method has a disadvantage in that there is no flexibility in changing the driving course because the driving course is permanently set. Furthermore, the method using electromagnetic induction wires has the problem of requiring a great deal of time and effort to bury the guide wires, and the method using optical tape has the problem that the tape may be damaged due to foot traffic, etc. There is a problem in that guidance errors occur due to dirt or damage.

Therefore, in order to solve the above problems, several new guidance methods other than the fixed route guidance method are currently being considered. One of the new guidance methods is one that guides unmanned vehicles based on image information. In recent years, the rapid improvement in the performance of image processing technology and microcombustion controllers, as well as the significant decline in the prices of microcombination controllers and components such as memory and A-D/D-A converters, have led to the rapid development of unmanned vehicles. It has become possible to incorporate a small and inexpensive image processing system into the system, and it is attracting attention as a next-generation guidance method.

A method for guiding an unmanned vehicle based on the above image information (hereinafter,
For example, as an image guidance method (simply referred to as an image guidance method),
The technology described in Japanese Patent No. 144106, that is, an imaging device is placed directly above and along the driving path, the imaging device performs visual recognition of the unmanned vehicle, and detects the amount of driving state of the unmanned vehicle. 2. Description of the Related Art There is a known technique for guiding an unmanned vehicle by transmitting the detection result to the steering and traveling device of the unmanned vehicle via a wireless communication device.

However, in the conventional technology described above, the degree of freedom of the unmanned vehicle is limited to some extent. In other words, even though the price has become cheaper, it is still economically difficult to install an expensive imaging device (including its attached computing device and communication device) in the entire building where unmanned vehicles are introduced. As mentioned above, they have no choice but to be placed along the travel route. Therefore, when changing the layout of a driving route or a building, a problem arises in that the imaging device has to be reinstalled on the new driving path. Furthermore, the basic problem with the above conventional example is that the unmanned vehicle does not know its own position by seeing it with its own eyes, but rather with the eyes of others on the ground. The purpose is to know one's own position by being taught.

In the future, more intelligent driverless cars will inevitably be required to see and make decisions with their own eyes. In other words, rather than simply receiving commands such as "go left,""gostraight," and "stop" from the ground side, the user does not simply receive commands such as "go left,""gostraight," or "stop." By guiding itself by comparing the destination with the current location, it will become closer to the above-mentioned intelligent system,
-Each driverless vehicle will be unique.

Therefore, by equipping each unmanned vehicle with an imaging device, the unmanned vehicle can
A technology that allows humans to "see" is being developed as a next-level guidance method. For example, data regarding the arrangement and shape of components may be input into the storage means in advance as a predicted pattern based on the position information of the unmanned vehicle, and the actual image sent from the imaging device on the moving unmanned vehicle and the predicted pattern There is a known technique for guiding an unmanned vehicle in such a way as to reduce the difference between the two patterns.

However, in the image guidance method described above, the storage capacity for storing the predicted pattern is large, the comparison and processing of the predicted pattern with the actual image takes time, and it is difficult to change the layout of the composition. It has been pointed out that there is a problem in that the above-mentioned predicted pattern needs to be re-written manually every time the unmanned vehicle changes course.

Now, in the flow of the prior art as described above, the purpose of the present application is to promote the intelligentization of unmanned vehicles by proposing an image guidance device with a higher degree of freedom, and to develop a guidance system for this purpose. It is to propose a mark.

[Means to solve the problem]

The present invention provides a mark that is placed at a predetermined position in a building into which an unmanned vehicle is introduced, and that is imaged by an imaging means installed on the unmanned vehicle, and that has a circular outer shape and that is located within the mark. A circular code is attached that is concentric with the mark and can be distinguished from other marks.

〔Example〕

FIG. 1 schematically shows an outline of an unmanned vehicle (1) operating in a building (2) using the image guidance system according to the present invention. The unmanned vehicle (1) according to the present invention is capable of running, steering, etc. using known techniques, and is equipped with a CCD camera (3) as an imaging means on the machine base. Furthermore, marks (5) that can be identified are arranged and pasted at predetermined positions on the ceiling surface (4).

The unmanned vehicle (1) images the ceiling (4) with the CCD camera (3) (hereinafter simply referred to as the camera) and marks (5).
By detecting and identifying information, it recognizes its current location and direction of travel.

According to the schematic diagram in Figure 2, the camera (3) has a lens (
6 and a screen (7), the screen (
7) is composed of many CCD element rows. The center of the lens (6) and the center of the screen (7) are at the same position in the vertical direction, and a coordinate system (X, y
) is set. The y-axis coincides with the vertical center line of the unmanned vehicle (1), and there is a distance (L) between the y-axis and the horizontal center line (S) of the unmanned vehicle (1). Furthermore, a factory coordinate system (x, y) within the ceiling plane is set for each mark (5). Note that there is a distance (D) between the lens (6) and the screen (7), and there is a distance (D) between the lens (6) and the ceiling surface (4).
It is assumed that there is a distance (H) between the two. Next, we will explain the concept of measuring the current position and traveling direction of an unmanned vehicle using the above configuration. Please note that the mark above (
5) and the image processing of the mark will be described later.

A) Concept of recognizing the current position and direction of movement of an unmanned vehicle using 2-mark recognition.

The basic idea is that the coordinates (x,
y), first, the camera coordinates (Xo) are obtained by directly translating the coordinates (X, y) to the ceiling surface.

yo) and further converts the camera coordinates (Xo.

y') and the factory coordinates (X, Y) on the ceiling surface, the current position and direction of travel are recognized. below,
I will explain this in more detail, but first I will list the prerequisites for this idea. (i) Camera (3) is mounted on the ceiling (
4) is oriented vertically. (ii) Mark (5)
Create many types of screens and install them at intervals of about half the field of view of the camera (3) so that the screen (7) of the camera (3) is always visible.
It is assumed that at least two marks are imaged within the area.

(iii) If three or more marks are imaged, any two marks are adopted and the others are ignored. (iv) It is assumed that the distance between the camera (3) and the ceiling (4) is known and constant. If there is variation, it is assumed that the height of each mark from the floor is also known.

Now, let the coordinates of marks A' and B' on the screen be (xa, ya) and (xb, yb), respectively.
and the distortion correction coefficients EX and Ey of the optical system, the mark A at the camera coordinates (X', y')
, B coordinates (xa, ya), (xb, yb)
can be expressed as.

On the other hand, the coordinates of marks Δ and B in the factory coordinate system are ? -riA (Xa, Yb), ? -riB (Xb, Yb)
-CII).

When the factory coordinates of the origin P of the camera seat at(x', y') are P (xo, yo), the relational expression for coordinate transformation is P (XO, yo) and θ can be found by substituting the coordinate values of When installing the camera from the center of the car, it is necessary to determine how many degrees the center is tilted counterclockwise from the y-axis of the factory coordinate system.

B) Concept of recognition of the current position and direction of travel of an unmanned vehicle by one mark recognition.

If a single mark can be used to recognize information about which mark it is and in which direction the mark is located (details will be described later), just by recognizing one mark, it is possible to The current location and direction of travel of the vehicle are determined.

That is, although the above [■] equation is only one equation because there is one set of coordinate information, the value of θ is known from the above information on the direction, and the above P (KO, yo) can be found. The subsequent processing is the same as in case A) above.

C) Control structure of unmanned vehicle (see block diagram in Figure 4) Next, the control structure of the unmanned vehicle (1) according to the present application will be explained.

That is, this control structure is composed of the following blocks.

a) CCD camera (3) This camera (3) is oriented perpendicularly to the ceiling surface (4), and the image input through the lens is projected as image information on a screen made up of multiple pixels. Served.

b) Vision controller (10) Extracts only the target mark (5) from the image data of the ceiling surface captured by the above CCD camera (3), reads the center coordinates of the mark and the code of the mark on the CCD screen, and controls the main Controller (11) Periodically reports.

C) Main controller (11) A calculation unit (12), coordinate table (13), which will be explained below.
It is composed of a travel control section (14), map data (15), and a transfer control section (16).

d) Arithmetic unit (12) Calculates the above A from the local coordinate values of the mark (5) obtained from the vision controller (lO), the mark code, and the coordinate values of each mark in the factory coordinate system obtained from the mark coordinate table (13). ), B) to calculate the position coordinates and orientation of the unmanned vehicle (1) in the factory coordinate system, and periodically report these to the travel control unit (14).

e) Coordinate table (13) In the factory coordinate system for each mark (5) The coordinates are entered.

f) Travel control unit (14) Determines the travel route based on the destination and memory map data (15) instructed by the communication controller (17), and servo driver (18) which is the travel and steering drive system.
Instructs driving data.

Compare the position and direction data of the unmanned vehicle reported from the calculation unit (12) with the destination information from the map data (15), and if there is a discrepancy beyond tolerance, correct the driving data and drive. , servo driver (1) which is the steering drive system
8) Give instructions.

In addition to data on the position and orientation of the unmanned vehicle (1) reported from the calculation unit (12), the position and orientation of the unmanned vehicle (1) are calculated using encoder output (19) from the motor (M) of the driving/steering drive system. and interpolates the observation interval based on vision.

Data on the position, direction, and status of the unmanned vehicle (1) are periodically reported to the communication controller (17).

g) Communication controller (17) The communication unit receives destination, start, stop, transfer instructions, etc. from the ground controller (20) via the ground side communication controller (21) and communication unit (22).
23) and reports each time to the main controller (11).

Information such as the current point, next stop position, status code, etc. from the main controller (11) is sent to the ground controller (20).
Report in response to a call from.

h) Ground controller (20) Accepts transport requests from CPU (24), transport request setting board, etc., and assigns the transport request to the unmanned vehicle considered to be the most efficient.

Collision prevention is managed based on data such as the next stop reported from the unmanned vehicle (1), and instructions to stop and start are given to the unmanned vehicle (1) as necessary.

Various status data reported from the unmanned vehicle (1) is displayed in animation on the graphic display (25) to enable real-time monitoring of the system status.

In offline mode, use the CAD function to define maps and mark coordinates to create an unmanned vehicle (1
) has a data creation function to download to.

i) Transfer robot control unit (26) Although this embodiment shows a transfer port (27) mounted on an unmanned vehicle (1), the transfer robot (27) is A detailed explanation will be omitted since it deviates from the main purpose.

C) Marks Next, the marks will be explained in detail. Note that the marks described in detail below are related to the KIWli of the current position and direction of movement of the unmanned vehicle based on the two-mark recognition described in item A) above.

An example of mark (5) is shown in FIG. This mark (5) has a circular shape, and from its outer periphery, a first black sheet band (30) consisting of a black part all around the circumference, a first black sheet band (
a first white sheet band (31) consisting of the inner white part of 30);
The cord sheet belt (3) inside the first white belt belt (31)
2), a second black sheet band (33) consisting of the black part inside the code sheet band (32); a second white sheet band (34) consisting of the white part inside the second black sheet band (33); The center black sheet portion (
35). Each black sheet band (30) (33) in the black part and the center black sheet part (35) are made of a sheet with a color that reflects less light such as black, and each sheet band (31) (34) is made of a sheet with a color such as white. Use a sheet that has a color that reflects a lot of light and is free from diffuse reflection, scratches, and stains. Although the color of the ceiling surface may be either black or white, it is assumed that it is black in this embodiment. The code sheet band (32) is divided in the radial direction into n bits (7 bits in the figure, and an embodiment using 7 bits will be described below), and each bit is further divided into three equal parts. Hereinafter, the area divided into three equal parts will be referred to as a small area.

E) Operation of mark signal discrimination Next, the operation of distinguishing the mark (5) will be explained.

The image of the ceiling surface taken by the camera (3) is sent to the Visigin controller (lO) and the controller (10)
Then, as shown in FIG. 12, the center position coordinates and code contents of the mark (5) are read out.

(First step) The surface information captured by the camera (3) is input into the controller (10) as one signal by scanning in the horizontal direction. As an example, signals corresponding to the scanning lines (Scl to 5c5) on the right side of FIG. 5 are shown as signal lines (Sgl to 5g5) in FIG. 6, respectively.

(Second Step) Excessive brightness from a lighting fixture or the like is determined as a disturbance signal from the above signal (details are omitted), and the signal is binarized by comparison with a set threshold value.

(Third Step) On the other hand, a horizontal template (36) and a vertical template (37) as shown in FIG. 7.8 are manually installed in the controller (10) in advance. The templates (36) and (37) have the same structure and correspond to the second white sheet portion (34) and the center black sheet portion (35) of the mark (5). That is, it has an arbitrary number of black detection pixel areas (hereinafter simply referred to as black pixel areas) (38) (39) on both sides, and the width (
A white pixel area (40) (
41) is formed, and a black pixel area (42) having the same width (Fb) as the diameter of the central black sheet portion (35) is formed at the center inside thereof.

The horizontal template (36) is compared with each image signal, and the horizontal coordinates of the matched locations are detected.

(Fourth step) At the same time as the matching detection using the horizontal template (36), matching detection is performed using the vertical template (37) to detect the vertical coordinates of the matched location.

(Fifth step) By finding the intersection of the horizontal and vertical coordinates detected in the third and fourth steps, the center position coordinate (Sn>) of the mark (5) within the camera (3) is detected.

(6th to 9th steps) As above, mark (5th to 9th steps)
) is detected, then the center position (Sn
) in a clockwise direction at a distance of radius (Ra).

Scanning according to the radius (Ra) is to scan just above the code sheet band (32).

The starting point for scanning can be anywhere, and the starting point is a place where three or more small areas of 1 bit are consecutive.
(St) and then reads the information on the code sheet band (32). Figure 9.10 shows the reading state.

In this example, the three subareas are black (b) and white (W).
- "0" for black (b), "0" for black (b) - white (W
) - White (W) corresponds to "1". Therefore, in the embodiment, the code "r'010100" is read, and the unmanned vehicle recognizes that the mark corresponds to the code. 2 for 6 bits
@ = 64 types; in 10 bits, 2'' = 1024 types can be identified.

As mentioned above, the mark (5) is circular, and the code of the mark is also located on the circumference of concentric circles. Therefore, the center position of the mark and the code content can always be accurately read from any direction regardless of the tilt of the unmanned vehicle.

In addition, if the last code among the above codes is "1", there are five consecutive small areas (W), and there is a risk that it may not be possible to recognize where the start bit ends, so if three or more small areas are consecutive, From then on, when the black (b) small area appears, it is recognized as the start of the first bit.

F) Marks of Other Embodiments Next, marks related to the recognition of the current position and traveling direction of an unmanned vehicle by one mark recognition in the above B) will be explained.

The mark is shown in FIG. In addition, the above D),
The same reference numerals are given to the same parts as in section E), and the explanation is omitted.

This mark (5) has a black part (43) on the first white sheet band (31) for direction recognition. Kurobe (43
) are attached to all marks in the same direction and at the same position. For example, the black part (
43) is attached.

The signal discrimination of the above mark (5) is based on the code sheet band (
32) Along with the upper scan Jung, scan the first white sheet band (3
1) is also scanned to detect the position of the black part (43).

By detecting the direction of the black part (43) in the camera image, it is possible to relatively recognize the direction of the unmanned vehicle in the factory coordinate system. In the case of this embodiment, the starting point of scanning is an arbitrary specific point, and the direction of the mark (5) is detected based on the distance from the specific point (starting point) to the black part (43). Note that it is also possible to use the start bit (St) as a substitute for the black part (43).

G) Regarding the guidance of unmanned vehicles, place the mark (5) described in item D) or item F) above on the camera (3).
), the vision controller (10) reads the center position coordinates (Sn) and code contents of each mark (5), and based on the read information, the arithmetic unit (12) calculates the above item A) or B). Through the process, the current position and traveling direction of the unmanned vehicle (1) in the factory coordinate system are recognized. Based on the information recognized by the calculation unit (12), the driving control unit (
14) to instruct the driving data to the servo driver (18)
tell. The control unit (14) includes a communication controller (
The map data (15) that stores the destination indicated by 17) and the driving route within the factory and the above calculation 1iR3 (
12) The driving of the unmanned vehicle is guided based on the information from 12).

H) Layout changes If the travel routes stored in the above map data (15) are all routes within the factory, you can change the layout of the unmanned vehicle by simply changing the destination instruction from the communication controller (17). The run will be changed. In addition, if you change the layout in the factory and make a new driving route from a part that was not a driving route, or vice versa, you can use the map data (15
) only need to change some of the memory contents. Of course, the mark (5) on the ceiling and the camera (3) on the unmanned vehicle remain the same.

In other words, since the unmanned vehicle is able to recognize its current location as the factory coordinates at any location within the factory, when changing the driving route: At least, only the coordinate data given to the unmanned vehicle must be changed. No other hardware changes are required.

〔Effect of the invention〕

As is clear from the above description, according to the present invention, the outer shape of the mark is circular, and a circular code that is concentric with the mark and distinguishable from other marks is attached within the circle. , the center position of the mark and the code content can always be accurately read from any direction regardless of the tilt of the unmanned vehicle.

Therefore, unmanned vehicles can drive while always recognizing their current location, and as a result, they have the flexibility to respond immediately to changes in layout, making them more intelligent.

[Brief explanation of the drawing]

Fig. 1 is a schematic diagram schematically showing the operation status of an unmanned vehicle in a building, Fig. 2 is a schematic diagram to explain the concept for position recognition of an unmanned vehicle, and Fig. 3 is a side view. Fig. 4 is a block diagram showing the control structure of the unmanned vehicle, Fig. 5 is a front view showing the mark, Fig. 6 is a schematic diagram for explaining the scanning state of the mark, and Fig. 7 is a schematic diagram showing the horizontal template. Figure 8 is a schematic diagram showing a vertical template, Figure 9 is a schematic diagram illustrating scanning for reading code information from marks, and Figure 1O is a schematic diagram illustrating analysis of code information. , FIG. 11 is a front view showing another embodiment of the mark, and FIG. 12 is a flow chart for mark signal discrimination. (1) Unmanned vehicle (2) Building (3) Camera (imaging means) (4) Ceiling surface (5) Mark (10) Vision controller (analysis means) (12
) Calculation unit (calculation means) (13) Coordinate table (storage means) (14) Travel control unit (15) Map data

Claims (1)

[Claims] A mark that is placed at a predetermined position in a building into which an unmanned vehicle is introduced and that is imaged by an imaging means installed on the unmanned vehicle, the outer shape of which is entirely circular, and a circle that is concentric with the mark within the mark. A mark for guiding unmanned vehicles, characterized by a circular code that can be distinguished from other marks.