JPS61251911A - Method for guiding unattended moving body - Google Patents

Abstract

PURPOSE:To set various running courses different from a reference course and guide a moving body along changed courses by changing a target position of deviation or both of the target position of deviation and a target angle of deviation in each position of the reference course formed with markers. CONSTITUTION:Casters 3 are arranged on both sides in front and rear parts of a car body 2 of an unattended moving body 1, and driving wheels 4L and 4R are arranged in the center part, and an ITV camera 6 as a visual means and a light projector 7 are arranged on a supporting base 5 in the front of the car body 2. Guide markers 8 are arranged interruptedly along the preliminarily set reference course on which the moving body 1 runs, and these markers are arranged at such intervals that two markers 8 are always within the visual field of the camera 6. The output from the camera 6 is converted by an A/D converter 13 in a guide device, and one picture written in a frame memory 14 is read out to a CPU 12. This picture is operated with counted values from pulse generators 9L and 9R belonging to driving wheels 4L and 4R, and the target position of deviation or both of the target position of deviation and the target angle of deviation in each position of the reference course are changed to set various running courses.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a method for guiding an unmanned vehicle using visual means.

[Conventional technology]

Various methods of guiding an unmanned moving object using visual means have been proposed in the past. For example, JP-A-59-629
No. 17 recognizes retroreflective signs placed discretely along the route using visual means installed on the unmanned vehicle, and detects azimuth and lateral shifts of the unmanned vehicle based on the recognized signs. However, a guidance method for steering the moving body so that these deviations are corrected is disclosed.

[Problem that the invention seeks to solve]

However, all of the conventional guidance methods guide a moving object to travel on a preset route, and therefore, for example, a moving object traveling on the preset route is guided along that route in an arbitrary travel section. It was not possible to freely change the route, such as shifting to one side or moving a moving object traveling on the negative side to the other side of the route in a certain travel section. .

[Means for solving problems]

In view of such conventional problems, in the present invention, guidance signs are intermittently arranged along a preset reference route, and the target deviation of the unmanned moving object at each position on the reference route or the target deviation and presetting both target deviation angles, causing at least two of said signs to be recognized by visual means provided on said unmanned vehicle, and deflection of said unmanned vehicle with respect to said reference path based on said recognized signs; Alternatively, both the deflection and the deflection angle are obtained, and the deflection of the unmanned moving object or both the deflection and the deflection angle for each position on the reference path are determined by the target deviation or the target deviation and the deflection angle for each position on the reference path. The unmanned vehicle is steered so as to match both of the target yaw angles.

[Effect]

According to the present invention, various travel routes different from the reference route are set by changing the target deviation or both the deviation and the target yaw angle for each position on the reference route.

〔Example〕

Hereinafter, the present invention will be described in detail with reference to the drawings. Figures 1 and 2 are a side view and a plan view, respectively, conceptually showing an example of an unmanned moving object 1 guided by the method of the present invention. be.

As shown in the figure, this moving body 1 has casters on both the front and rear sides of the vehicle body 2, and separate motors M on both sides of the center part.
Drive wheels 4R and 4L, which are rotated by ML, are provided. A TV camera 6 serving as visual means ('TV camera 6) is disposed on a support base 5 bored in the front part of the vehicle body 2, and a projector 7 is disposed above the camera 6.

The camera 6 is mounted at an appropriate angle of depression so that a predetermined range of the road surface on the front side of the vehicle body 2 is included in the field of view, and the floodlight 7 is mounted so as to illuminate the field of view of the camera 6. . The motors MR and ML are respectively attached with pulse generators 9R and 9L, such as pulse encoders, which output pulse signals as the motors rotate.

The signs 8 placed on the road surface function as landmarks to guide the moving body 1, and in this embodiment, they have retroreflectivity, that is, the property of reflecting light in the same direction as the incident light. It uses glass beads with . These signs 8
are arranged along the running path of the moving body 1, and a line connecting them functions as a reference route for the moving body 1, as will be described later. The intervals between the markers are set so that at least two markers are always within the field of view of the camera 6.

Here, the principle of guiding the moving object 1 while capturing the sign 8 with the camera 6 will be explained.

Now, if we set the road surface P K There is a geometric correspondence with m. Therefore, image Q
If the coordinate m of the road surface P is detected, the coordinate M of the road surface P can be obtained, and the angle γ (angle of depression) between the line segment kite and the road surface P, and the line segments OM and Y obtained by projecting the line segment blood onto the road surface P. The angle β (azimuth angle) formed with the axis is also determined.

Note that in the figure, point C indicates the principal point of the lens of the camera 6. Further, for the X and Y coordinates on the road surface P, the coordinate origin O is the point where the perpendicular line passing through point R intersects with the road surface, and the Y axis thereof is set in the traveling direction of the moving body 1.

Next, as shown in FIG. 4, the coordinate M1 on the road surface.

Consider the case where M exists within the field of view of the camera 6.

An angle of depression γ4 and an azimuth β1 for the coordinate M1, and an angle of depression γ3 and an azimuth β for the coordinate M.

is determined from the corresponding coordinates m□ and m1l (not shown) on the image plane Q of the camera 6, as described above. If these are found, the coordinate M1.

The angle ψ between the line segment passing through M and the Y axis and the length d of the drawing line from the 0 point to the line segment are calculated using the following formulas (1) and (2), respectively.
) can be calculated based on

However, h is the distance between the 0 points and the above coordinates M1 and M2 indicate the position of the sign 8, and the angle ψ is the deflection angle of the moving body 1 with respect to the line segment connecting those signs 8. , and the distance d indicates the deviation (lateral deviation) of the moving body 1 with respect to the above-mentioned line segment.

Therefore, the reference route t1 as illustrated in FIG. 8 is constructed using the marker 8, and the target deviation ar (or the deviation) of the moving body to be shown for each section Pj + Pl+1 +... of this route t1 is The actual deviation d (or the deviation d and the deviation angle ψ) of the moving body 1 for each section is the preset deviation d, (or the deviation dr and the deviation angle ψ
r), the moving body 1 can be guided along various routes based on the reference route t1, for example, the route 1.1 shown in the figure.

The above is the principle of the method according to the present invention, and this method
It is carried out using an apparatus as illustrated in the figure. Hereinafter, embodiments of the present invention will be described with reference to the same figure.

The video signal output from the camera 6 is binarized by the A/D converter 13 and then written to the frame memory 14, and the frame memory 14 is written every time one screen is created.
The stored contents are taken into the CPU 12.

As described above, since the marker 8 is formed of a glass bead having retroreflectivity, it is captured by the camera 6 as a bright spot image. Therefore, the CPU 12 controls the camera 6 based on the bright spot image data stored in the frame memory 11.
A plurality of (for example, 2 to 3) signs 8 that exist within the visual field of
, and select two of those signs, for example, two adjacent signs. Then, the coordinates M 2M on the road surface shown in Fig. 4 for these two signs are determined, and the angle of depression γ
1 and the coordinate M, the depression angle γ3 and the azimuth angle β are η
Then, the calculations shown in equations (1) and (2) above are executed to determine the argument ψ and the deviation d of the moving body 1.

The route memory 15 shown in FIG.
1 is stored in advance. That is, for example, when a reference path t1 as shown in FIG. 8 by the marker 8 is constructed, the target deviation dr and the target argument ψ1 for the positions pt, Pi+1, . . . are stored.

The CPU 12 counts the number of passing signs 8 from the output of the camera 6 and determines the positions Pi l Pi+1, . . .
1 target side d and target declination angle ψ1 for those positions are sequentially read out from the mesori 15 'f, i
Then, based on the read dr, ψ1 and the detected actual deviation d and argument ψ of the moving body 1, speed commands V, , VL for the motors MR, ML shown in FIG. 2 are created and output.

That is, the CPU 12 controls the mobile object 1 as shown in FIG.
The program includes a program that adds a value K to a running speed command V to create a speed command V, and subtracts a value K from the speed V to create a speed command vL. The circuit is connected to amplifier 1 via D/A converters 16 and 17.
Added on 8.19.

The above values are changed in the manner shown in FIG. 7 for Δv=(ar-d)+(ψ, -ψ). Therefore, if the difference between the preset deviation d and the actual deviation dr and the difference between the target yaw angle ψ and the actual yaw angle ψ are both small and ΔV has a value within the dead zone 0 shown in the figure, K=0 and vR=v.

A speed command of vL=v is created, and in this case, the driving wheels 4 rotate at a speed of Rt4L7'% and the moving body 1 travels straight.

Further, when ΔV takes a positive value larger than the value within the dead zone O, V:>VL, so the rotational speed of the right drive wheel 4R becomes greater than that of the left drive wheel, and the moving object 1 moves to the left. Conversely, if the vehicle 1 takes a negative value larger than the value within the dead zone 0, the vehicle 1 becomes VR (VL), so the vehicle 1 is steered to the right.

Note that in the above, the greater the absolute value of ΔV, the greater the forward direction.

Since the above device has such an effect, the position P shown in FIG.
t r Pt+1+ P1+2 The target deviation d for e... is d : (> 0 ), dl+1 (
〉0), d amount +3 (<O).

..., and the target deflection angle ψ is set to ψ1=0, for example, in the section Li, the moving body 1 is guided so that the deflection of the moving body 10 is dl and the deflection angle is 0, It is induced in the same manner in other sections as well.

Therefore, in this example, the route t□' indicated by the dotted line in the same figure becomes the travel locus of the moving body 1.

According to the present invention, as shown in FIG. 9, the reference path t,
It is also possible to guide the moving body 1 along a route t2/ shifted by Z do from It is also clearly possible.

In the above example, the preset argument angle ψ is fixed to ψ = 0, but an appropriate value of argument angle ψ is set at each travel position depending on the form of the route to be guided.

Further, in the above example, both the target deviation and the target declination angle are specified, but the present invention can be implemented even if only the deviation dr is specified. In other words, ΔV=(dr-d) is
It is also possible to calculate the value of 12 and guide the moving body 1 based on the value of . However, by specifying both the deviation dr and the argument ψ, the route of the moving body can be changed with higher accuracy.

In the above embodiment, a glass bead having retroreflectivity is used as the sign 8, but instead of this glass bead, a corner cube prism, an adhesive tape having a predetermined shape having retroreflectivity, a guardrail, etc. may be used. A light reflector or the like may also be used.

When such markers are used, if they have a predetermined shape, they can be more easily distinguished from other objects on the image.

It is also possible to use a light emitter such as an IJD, a light bulb, or a fluorescent lamp as the sign 8, and in this case, the floodlight 7 becomes unnecessary. Note that if a light emitter that emits light of a specific wavelength is used as a marker, disturbances can be removed by providing a filter on the visual means side that allows only the light of the specific wavelength to pass through. Furthermore, if the light emitting body is made to blink at a predetermined period and the visual means performs image processing using the blinking period, disturbances can also be removed.

In short, various signs can be used as the sign 8 as long as the visual means can distinguish it from other objects, and it is sufficient to select and use the one that is most suitable for the traveling environment of the mobile object 1.

Furthermore, in the above embodiment, the television camera 6 is used as a visual means.
However, if a light emitter is used as the marker 8, a two-dimensional semiconductor device detector (position sensor) is used.
can also be used as a visual aid.

Furthermore, in the embodiment described above, the positions Pi # Pi-H, . Recognizes 1,000 turns with different special shapes,
With this, it is also possible to detect each position. It is also possible to provide information indicating each of the above positions from a sign post placed on the side of the track.

Note that, for example, when the moving object 1 is caused to change its course at a position where it has traveled a predetermined distance from the position Pi, after the moving object 1 reaches the position P1, the 7 lugs shown in FIG. 1 occur. The output pulses of the devices 9R and 9L are outputted to the counter 10,
11 to detect the route change position. In this case, the CPU 12 uses the average value of the count values of both counters as distance data in order to obtain the traveling distance of the center position of the moving body 1.

〔Effect of the invention〕

According to the present invention, by changing the target deflection or both the target deflection and the target deflection angle for each position on the reference route formed by the sign, it is possible to travel along various travel routes different from the reference route. This has the added advantage of being able to guide the moving object.

[BRIEF DESCRIPTION OF THE DRAWINGS] FIGS. 1 and 2 are a side view and a plan view conceptually showing an example of an unmanned moving object guided by the method of the present invention, and FIG. A diagram showing the geometric relationship between coordinates and coordinates on a road surface, FIG. 4 is an explanatory diagram for determining the deflection and declination of a moving object, and FIG. 5 is a guidance device applied when implementing the present invention. A block diagram showing an example, Fig. 6 is a diagram illustrating a system for creating a speed command signal, Fig. 7 is a graph showing how the values shown in Fig. 6 change, Figs. FIG. 9 and FIG. 10 are conceptual diagrams each illustrating a manner in which a moving object is guided with respect to a reference travel route. 1... Unmanned mobile object, 4R, 4L... Drive wheel, 6...
・ITV camera, 7... Floodlight, 8... Sign, 9R
, 9L...Pulse generator, 12...CPU, 13.
・・Science converter, 14...°frame memory, 15...
Route memory. O-7″0 O-a)”c. 〇－の

Claims (2)

[Claims] (1) Guidance signs are disposed intermittently along a preset reference route, a target deflection of the unmanned moving body is preset at each position on the reference route, and a visual means provided on the unmanned moving body is provided. to recognize at least two of the marks, and determine the deviation of the unmanned moving body from the reference route based on the recognized marks, and determine the deviation of the unmanned moving body for each position on the reference route. A method for guiding an unmanned moving body, characterized in that the unmanned moving body is steered such that the deviation matches the target deviation for each position. (2) In addition to disposing markers intermittently along a preset reference route, the target deflection and target deflection angle of the unmanned moving body at each position on the reference route are preset, and the markers are installed on the unmanned moving body. At least two of the signs are recognized by a visual means, and the deviation and declination angle of the unmanned vehicle with respect to the reference route are determined based on the recognized signs, and the A method for guiding an unmanned moving body, comprising steering the unmanned moving body so that the deflection and yaw angle of the unmanned moving body match the target deflection and yaw angle for each position.