JP2013117838A - Unmanned conveyance system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To achieve reduction of a construction period, improvement in construction efficiency, and a reduction in construction cost in laying operation of a guide line.SOLUTION: A guide line 2 includes a first linear part 21 and a second linear part 22 bent from an end of the first linear part 21 at a predetermined angle. First detection means 11 outputs a first direction angle and a first deviation of the guide line 2 in a first detection region 11a on a side before a vehicle body, and second detection means 12 outputs a second direction angle and a second deviation of the guide line 2 in a second detection region 12a on a side behind the vehicle body. Control means swivels front wheels 13, 14 by a front-wheel swivel angle obtained by correcting the first direction angle in a direction in which the first deviation approaches zero using a correction value obtained by multiplying the first deviation by a predetermined gain on the basis of output from the first detection means 11, and swivels rear wheels 15, 16 by a rear-wheel swivel angle obtained by correcting the second direction angle in a direction in which the second deviation approaches zero using a correction value obtained by multiplying the second deviation by a predetermined gain on the basis of output from the second detection means 12.

Description

  The present invention relates to an unmanned conveyance system including a guide line laid along a travel route and an unmanned vehicle that travels while detecting the position of the guide line.

  2. Description of the Related Art Conventionally, in factories, warehouses, and the like, an unmanned conveyance system including a guide line laid on a road surface and an unmanned vehicle that travels along the guide line has been used. Various types of such unmanned conveyance systems are known. For example, Patent Documents 1 and 2 disclose an unmanned conveyance system including an unmanned vehicle that travels along a guide line.

  The conventional unmanned vehicle is provided with detection means for detecting the guide line at the front of the vehicle body, and the control means controls the turning drive of the wheels provided on the vehicle body based on the output of the detection means, It is configured to travel following the guide line. In the conventional unmanned conveyance system, in the section where the unmanned vehicle changes the posture angle in the perpendicular direction, the corner portion 25 of the guide line 2 is an arc line formed of a smooth curve as shown in FIG. It is composed of an arcuate line formed by connecting a plurality of short straight lines as shown in (b) in an arcuate shape at a sufficiently shallow angle.

  In the conventional unmanned vehicle, the detection unit and the control unit are configured so as to travel along the corner portion 25 of the guide line 2 configured by an arc line or an arc-shaped line. Therefore, in the conventional unmanned conveyance system, when laying the guide line, it is necessary to use a measuring instrument for a curve in addition to a measuring instrument for a straight line, and to install an arc line or an arc-shaped line member at a corner portion. was there. As a result, the installation work of the induction line is very time-consuming, and the construction period is prolonged, the construction efficiency is lowered, and the construction cost is increased.

JP-A-11-240446 JP 2001-265438 A

  Therefore, the problem to be solved by the present invention is to provide an unmanned conveyance system that can shorten the construction period, improve the construction efficiency, and reduce the construction cost in the laying operation of the induction line.

In order to solve the above problems, an unmanned conveyance system according to the present invention includes:
An unmanned transport system comprising a guide line laid along a travel route and an unmanned vehicle that travels while detecting the position of the guide line,
The guide line includes a first straight part and a second straight part bent at a predetermined angle from the end of the first straight part,
Unmanned vehicles
A front wheel provided at the front of the vehicle body;
A rear wheel provided at the rear of the vehicle body;
First detection means provided at a front portion of the vehicle body for detecting a guide line;
A second detection means provided at the rear of the vehicle body for detecting the guide line;
Control means for controlling the turning angle of the front and rear wheels,
The first detection means outputs the first direction angle and the first deviation of the guide line in the first detection region on the front side of the vehicle body,
The second detection means outputs the second direction angle and the second deviation of the guide line in the second detection region on the rear side of the vehicle body,
The control means
Based on the output from the first detection means, the front wheel turning angle is set by correcting the first direction angle in a direction in which the first deviation approaches zero using a correction value obtained by multiplying the first deviation by a predetermined gain. Turn the front wheel at the front wheel turning angle,
Based on the output from the second detection means, the correction value obtained by multiplying the second deviation by a predetermined gain is used to correct the second direction angle in the direction in which the second deviation approaches zero, thereby setting the rear wheel turning angle. Set and turn the rear wheel at the rear wheel turning angle.

Preferably,
The guide line includes a third straight portion that is bent at a predetermined angle from an end of the second straight portion,
The third straight line portion is provided in a direction of about 90 degrees with respect to the first straight line portion.

Preferably,
The first and second deviations are based on the center position of the first and second detection regions at the edges on the traveling direction side.

Preferably,
The first and second detection means include imaging means for imaging the first and second detection areas.

  As described above, in the unmanned conveyance system according to the present invention, the unmanned vehicle includes two detection means at the front and rear portions of the vehicle body, and the direction angle of the guide line in the detection area at the front and rear of the vehicle body by each detection device. And detecting deviations. Based on the output of the detection means, the unmanned vehicle turns the front wheel along the guidance line on the front side of the vehicle body, and turns the rear wheel along the guidance line on the rear side of the vehicle body. As a result, the unmanned vehicle does not have an arc line or an arc-shaped line at the corner portion between the first straight line portion and the second straight line portion, but is a straight portion bent at a predetermined angle. Can drive without departing from the guidance line. As a result, in the unmanned conveyance system according to the present invention, it is not necessary to use a measuring instrument for curved lines and a curved member when laying a guide line, and it is only necessary to use a measuring instrument for straight lines and a linear member. Shortening the construction period, improving construction efficiency, and lowering construction costs.

The top view which shows schematic structure of the unmanned vehicle which concerns on this invention. The block diagram of the unmanned vehicle which concerns on this invention. The top view which shows schematic structure of the unmanned conveyance system which concerns on this invention. In the case of FIG. 3, FIG. 4 (a) is a plan view for explaining the front wheel turning angle of the front wheel, and FIG. 4 (b) is a plan view for explaining the rear wheel turning angle of the rear wheel. FIG. 5A is a plan view illustrating a detection unit according to another embodiment, and FIG. 5B is a plan view illustrating a detection unit according to still another embodiment. The top view which shows the conventional guidance line.

  Hereinafter, an automatic guided system according to the present invention will be described with reference to the drawings.

  As shown in FIG. 1, the unmanned vehicle 1 includes a vehicle body 10. The unmanned vehicle 1 is provided with a pair of front wheels 13 and 14 at a front portion 1 a of a vehicle body 10. In addition, the unmanned vehicle 1 is provided with a pair of rear wheels 15 and 16 on the rear portion 1 b of the vehicle body 10. A vehicle body center line C is set on a line connecting the center position of the front portion 1 a of the vehicle body 10 and the center position of the rear portion 1 b of the vehicle body 10. The vehicle body center line C is on a line connecting the center position of the front wheels 13 and 14 and the center position of the rear wheels 15 and 16. Therefore, the direction of the vehicle body center line C is the traveling direction (posture angle) 10a of the vehicle body 10.

  The unmanned vehicle 1 includes first detection means 11 at the front portion 1 a of the vehicle body 10. The unmanned vehicle 1 also includes second detection means 12 at the rear portion 1b of the vehicle body 10. The first detection means 11 is provided on the vehicle body center line C between the front wheels 13 and 14. The second detection means 12 is provided on the vehicle body center line C between the rear wheels 15 and 16.

  In this embodiment, the 1st and 2nd detection means 11 and 12 are comprised by imaging means, such as a CCD camera, and a two-dimensional arrangement color sensor. The first and second detection means 11 and 12 are configured such that the detection direction is directed toward the road surface, and the guide line 2 (FIG. 3) laid on the road surface is detected. The first detection means 11 acquires the image data of the first detection area 11a on the front portion 1a side of the vehicle body 10, and outputs it at a frequency of several to several tens of times per second, for example. Similarly, the 2nd detection means 12 acquires the image data of the 2nd detection area | region 12a in the rear part 1b side of the vehicle body 10, and outputs it with the frequency of several times-dozens of times per second, for example.

  As shown in FIG. 2, the unmanned vehicle 1 includes a control unit 5. As shown in FIG. 3, the control unit 5 controls the turning angles of the front wheels 13 and 14 and the rear wheels 15 and 16 so that the unmanned vehicle 1 travels along the guide line 2. The control unit 5 controls the front wheel turning angle of the front wheels 13 and 14 based on the output from the first detection means 11. Similarly, the control unit 5 controls the rear wheel turning angle of the rear wheels 15 and 16 based on the output from the second detection means 12.

  As shown in FIG. 3, in the present embodiment, the guide line 2 is configured such that the corner portion is a straight line in the section where the unmanned vehicle 1 changes the traveling direction 10 a (posture angle) to a right angle direction, and the first straight portion 21. The second straight portion 22 and the third straight portion 23 are configured. The unmanned vehicle 10 travels along the first straight portion 21, and then travels along the third straight portion 23 while changing the traveling direction 10 a by about 90 degrees. Therefore, the third straight part 23 is provided at an angle 2 a of about 90 degrees with respect to the first straight part 21. Further, the second straight portion 22 serving as a corner portion is provided at angles 2b and 2c of about 45 degrees with respect to the first straight portion 21 and the third straight portion 23. When the angle 2a is 90 degrees, the angles 2b and 2c may be in the range of 30 to 60 degrees.

Based on FIG. 4A, front wheel turning angles θ ₁₃ and θ _{14 in} the wheel directions 13a and 14a of the front wheels 13 and 14 with respect to the traveling direction 10a will be described. The first detection means 11 outputs the first direction angle θ ₁ and the first deviation e ₁₁ of the guide line 22 with respect to the vehicle body center line C in the first detection region 11 a on the front side of the vehicle body 10. A vehicle body center line C is set at the center position of the first detection region 11a. First detection means 11, in the traveling direction 10a of the side end side of the first detection region 11a, detects the shift amount (first _{deviation) e 11} of the induction line 22 and the vehicle body center line C in the travel direction 10a. Furthermore, the first detection means 11, the end side opposite to the traveling direction of the first detection region 11a, detects the shift amount e ₁₂ of the induction line 22 and the vehicle body center line C in the travel direction 10a. The first detection region 11a has a length _{D 1} in the traveling direction 10a.

Based on the shift amount (first deviation) e ₁₁ , the shift amount e ₁₂ , and the length D ₁ , the first direction angle θ ₁ of the guide line 22 in the first detection region 11 a is calculated by the following equation (1). Calculated. The shift amounts e ₁₁ and e ₁₂ are labeled “+” and “−” according to the left-right direction with respect to the vehicle body center line C. Further, the first direction angle θ ₁ is determined in the left-right rotation direction with respect to the traveling direction 10a according to the signs of “+” and “−”.
Θ ₁ = tan ⁻¹ ((e ₁₁ −e ₁₂ ) / D ₁ ) (1)

Further, the gain g ₁ is set according to the deviation amount (first deviation) e ₁₁ . By correcting the first direction angle θ ₁ using this gain g ₁ , the front wheel turning angle θ _{13 of} the front wheel ₁₃ and the front wheel turning angle θ ₁₄ of the front wheel ₁₄ are set. That is, the first direction angle θ ₁ is corrected in the direction in which the deviation amount (first deviation) e ₁₁ approaches zero, and the front wheel turning angles θ ₁₃ and θ ₁₄ are set. Therefore, when the deviation amount (first deviation) e ₁₁ is zero, the front wheel turning angles θ ₁₃ and θ ₁₄ are the same as the first direction angle θ ₁ . In the present embodiment, the front wheel turning angle θ ₁₄ of the inner front wheel 14 in the vehicle body rotation direction is slightly larger than the front wheel turning angle θ ₁₃ of the outer front wheel 13 in the vehicle body rotation direction so that the vehicle body 10 is easily bent. Is set.

Based on FIG. 4B, the rear wheel turning angles θ ₁₅ and θ ₁₆ of the rear wheels 15 and 16 with respect to the traveling direction 10a will be described. The second detection means 12 outputs the second direction angle θ ₂ and the second deviation e ₂₁ of the guide line 21 with respect to the vehicle body center line C in the second detection region 12 a on the rear side of the vehicle body 10. A vehicle body center line C is set at the center position of the second detection region 12a. The second detection means 12 detects a deviation amount (second deviation) e ₂₁ between the vehicle body center line C and the guide line 21 in the traveling direction 10a at the end of the second detection region 12a on the traveling direction 10a side. Further, the second detection means 12 detects a deviation amount e ₂₂ between the vehicle body center line C and the guide line 22 in the traveling direction 10a at the end opposite to the traveling direction of the second detection region 12a. The second detection region 12a has a length _{D 2} in the traveling direction 10a.

Based on the above-described deviation amount (second deviation) e ₂₁ , deviation amount e ₂₂ , and length D ₂ , the second direction angle θ ₂ of the guide line 21 in the second detection region 12a is calculated by the following equation (2). Calculated. The shift amounts e ₂₁ and e ₂₂ are labeled “+” and “−” according to the left-right direction with respect to the vehicle body center line C. Further, the second direction angle θ ₂ is determined in the left-right rotation direction with respect to the traveling direction 10a according to the signs “+” and “−”.
Θ ₂ = tan ⁻¹ ((e ₂₁ −e ₂₂ ) / D ₂ ) (2)

Further, the gain g ₂ is set according to the deviation amount (second deviation) e ₂₁ . By correcting the second direction angle θ ₂ using the gain g ₂ , the rear wheel turning angle θ _{15 of} the rear wheel 15 and the rear wheel turning angle θ 16 of the rear wheel ₁₆ are set. That is, the second direction angle θ ₂ is corrected in the direction in which the deviation amount (second deviation) e ₂₁ approaches zero, and the rear wheel turning angles θ ₁₅ and θ ₁₆ are set. Therefore, when the shift amount (second deviation) e ₂₁ is zero, the rear wheel turning angles θ ₁₅ and θ ₁₆ are the same as the second direction angle θ ₂ . In the present embodiment, wheel turning angle theta ₁₆ after the inner rear wheel 16 of the vehicle body rotation direction, so that the vehicle body 10 tends to bend, the wheel turning angle theta ₁₅ after the outer rear wheel 15 of the vehicle body rotational direction On the other hand, it is set slightly larger.

In the above embodiment, the first and second direction angles θ based on the shift amounts e ₁₁ , e ₁₂ , e ₂₁ , e ₂₂ and the lengths D ₁ , D ₂ in the first and second detection regions 11a, 12a. ₁ and θ ₂ are calculated. For example, in the bent portion between the first straight line portion 21 and the second straight line portion 22, the amount of deviation between the vehicle body center line C and the guide line 2 is detected at a number of points, and the minimum The first and second direction angles θ ₁ and θ ₂ may be calculated by calculating an approximate curve of the bent portion by the square method and using the tangent line of the approximate curve at the end sides of the detection regions 11a and 12a.

In the above-described embodiment, the first deviation e ₁₁ and the second deviation e ₂₁ are the difference between the vehicle body center line C and the guide line 2 at the edges on the traveling direction 10a side of the first and second detection regions 11a and 12a. Although the deviation amount is adopted, the deviation amount (deviation) in the traveling direction 10a between the vehicle body center line C and the guide line 2 at the center position of the first and second detection regions 11a and 12a may be adopted.

FIG. 5 shows an embodiment different from the above. In FIG. 5A, the detection means 11, 12 is composed of four one-dimensional magnetic sensors 100, 101, 102, 103. When the first and second direction angles θ ₁ and θ ₂ are calculated using the least square method described above, it is preferable to detect the amount of deviation between the vehicle body center line C and the guide line 2 at least at four locations. Further, as in the embodiment described in detail above, the first and second detection regions 11a and 12a are shifted based on the shift amounts e ₁₁ , e ₁₂ , e ₂₁ , e ₂₂ and the lengths D ₁ , D ₂ . When calculating the first and second direction angles θ ₁ , θ ₂ , as shown in FIG. 5B, the detection means 11, 12 has two one-dimensional magnets at both ends of the traveling direction 10 a of the detection regions 11 a, 12 a. The sensors 100 and 103 can also be arranged.

DESCRIPTION OF SYMBOLS 1 Unmanned vehicle 2 Guidance line 5 Control means 21 1st linear part 22 2nd linear part 23 3rd linear part 1a Front part 1b of vehicle body Rear part 11 of vehicle body 1st detection means 12 2nd detection means 11a 1st detection area 12a 1st 2 Detection regions 13, 14 Front wheels 15, 16 Rear wheels 13a, 14a Front wheel turning angles 15a, 16a Rear wheel turning angle θ ₁ First direction angle θ ₂ Second direction angle e ₁₁ First deviation e ₂₁ Second deviation g ₁ , g ₂ gain

Claims (4)

An unmanned transport system comprising a guide line laid along a travel route and an unmanned vehicle that travels while detecting the position of the guide line,
The guide line includes a first straight part and a second straight part bent at a predetermined angle from an end of the first straight part,
The unmanned vehicle is
A front wheel provided at the front of the vehicle body;
A rear wheel provided at a rear portion of the vehicle body;
First detection means provided at a front portion of the vehicle body for detecting the guide line;
Second detection means provided at a rear portion of the vehicle body for detecting the guide line;
Control means for controlling the turning angle of the front wheel and the rear wheel,
The first detection means outputs a first direction angle and a first deviation of the guide line in a first detection region on the front side of the vehicle body,
The second detection means outputs a second direction angle and a second deviation of the guide line in a second detection region on the rear side of the vehicle body,
The control means includes
Based on the output from the first detection means, a correction value obtained by multiplying the first deviation by a predetermined gain is used to correct the first direction angle so that the first deviation approaches zero. Set a turning angle, turn the front wheel at the front wheel turning angle,
After correcting the second direction angle in a direction in which the second deviation approaches zero using a correction value obtained by multiplying the second deviation by a predetermined gain based on the output from the second detection means. An unmanned conveyance system that sets a wheel turning angle and turns the rear wheel at the rear wheel turning angle. The guide line includes a third straight portion that is bent at a predetermined angle from an end portion of the second straight portion,
The unmanned conveyance system according to claim 1, wherein the third straight part is provided in a direction of about 90 degrees with respect to the first straight part.   3. The unmanned conveyance system according to claim 1, wherein the first and second deviations are based on a central position at an edge on the traveling direction side of the first and second detection regions.   The unmanned conveyance system according to any one of claims 1 to 3, wherein the first and second detection means include imaging means for imaging the first and second detection areas.

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