JPS61168023A - Guiding device of unmanned carrier car - Google Patents

Abstract

PURPOSE:To quickly return an unmanned carrier car to its moving route through simple steering correction, by irradiating induction tapes and adjacent nonreflecting tapes from two light sources provided on the car body and detecting the change in the reflecting quantity on the basis of their irradiation ratio, and then, calculating the deviation and deviating angle of the car body. CONSTITUTION:Each position O'1 and O'2 of detecting devices 11 and 12 represents that the deviating quantity and deviating angle between the center 5 of the route of an unmanned carrier car 1 and the center 8 of the carrier car 1 are respectively X and theta. In this case, two guidance tapes 61 and 62 are provided at right and left sides of the route and two nonreflecting tapes 10 are adjacently provided on both sides of each guidance tape 61 and 62. At the detecting device 11, its receiving light quantity theta1 is reduced by the hatched section due to the nonreflecting tape 10A adjacent to the guidance tape 61. At the detecting device 12, its receiving light quantity is measured similarly. Then the deviating quantity X and deviating angle theta are drawn through operation from the radius of the light receiving section, tape arranging distance, etc., and the steering of the carrier car is controlled.

Description

DETAILED DESCRIPTION OF THE INVENTION (A) Field of Industrial Application The present invention relates to a guidance device for an automatic guided vehicle that automatically travels along a preset route.

(B) Prior Art Regarding a guidance device for an automatic guided vehicle, a method is known in which an optical tape that can be optically identified is laid down on the floor along a route to guide the vehicle. In this method, the automatic guided vehicle guides the vehicle while detecting the amount of deviation from the route, but the means for detecting the amount of deviation from the route is, for example, a reflective tape laid on the floor and a large number of light receiving elements arranged. It is configured to detect and compare the amount of reflected light from the route, determine the steering angle based on the output signal, and guide the vehicle.

In this method, in order to improve the accuracy of detecting the amount of deviation from the path, the light-receiving elements are arranged at fine intervals, and the desired accuracy is achieved, but the large number of light-receiving elements makes the entire device complicated. There was a problem.

For this purpose, for example, a reflective tape laid on the floor along the travel path, and two sets of photoelectric sensors on the left and right sides perpendicular to the direction of travel of the automatic guided vehicle, and reflective tape laid on the floor. A method has been proposed in which the tape is detected, the amounts of light received by the light receiving elements of two sets of photoelectric sensors are compared, and the automatic guided vehicle is steered so that the amounts of light received by the two sets are equal.

However, with this method, if one of the sensors is at a position that is outside the width of the reflective tape laid on the floor, it is not possible to detect how far the position has deviated from the reflective tape, so it is not possible to detect the amount of deviation that needs to be corrected. This had the disadvantage of having to be guided to the correct route through repeated corrections several times.

In addition, conventional methods for determining the steering angle include detecting the deviation angle θ (vehicle body angle) between the traveling direction of the automatic guided vehicle and the center of the route, and detecting the deviation angle θ (vehicle body angle) between the center line of the automatic guided vehicle and the center of the route. There is a device that detects the offset position X in the lateral direction.

However, in the former (deviation angle detection method), the deviation angle of the automatic guided vehicle converges to a certain value with respect to the path center Xo, as shown in Figure 3 (A), but there is a certain limit to this convergence. A value Xc exists. In the latter case (deviation detection method in the lateral direction of the route), the travel trajectory of the automatic guided vehicle is such that the amount of deviation There is a tendency to run.

That is, in the former case, the vehicle runs while deviating from the route by a certain distance, and in the latter case, there is a problem in that the vehicle runs in a so-called oscillating motion.

(c) Purpose In view of the above circumstances, the present invention has been developed to guide the travel route of an automatic guided vehicle by using a small number of travel route detection devices (and to reduce the number of travel route detection devices lateral to the center of the travel route of the automatic guided vehicle). By detecting the amount of deviation X in the direction and the angle θ between the center of the route and the automated guided vehicle using a guidance tape laid on the floor and controlling the steering, the automated guided vehicle runs smoothly along the route. It is an object of the present invention to provide a guidance device for an automatic guided vehicle that can improve reliability and performance.

(D) Structure The present invention provides an automated guided vehicle that includes a guidance tape laid on a floor surface, and a steering device and a traveling drive device that detect the position of the guidance tape and automatically follow the guidance tape along a travel route. a detection device that irradiates the guide tape with a light source and detects the amount of light reflected from the guide tape; and means that calculates the deflection and deflection angle of the vehicle body based on the signal from the detection device;
This is a guidance device for an automatic guided vehicle, comprising a control device that outputs a steering signal and a drive signal based on the calculation means.

(E) Embodiment FIG. 1 is a plan view showing the running relationship of an automatic guided vehicle showing a first embodiment of the present invention, FIG. 2(a) is a side view, and FIG.
b) is an explanation showing a specific embodiment of the detection device provided in the automatic guided vehicle.

1 is a truck of an automatic guided vehicle, and is equipped with a steering wheel 2 at the front or rear part and a driving wheel 3.4 at the rear or front part of the truck.

Note that the steered wheels 2 are configured to freely turn around a vertical axis via a speed reduction mechanism by a steering motor (not shown). Further, the drive wheels 3.4 are driven by a drive motor via a deceleration mechanism (not shown).

5 indicates the center of the travel path of the carrier. Guide tapes 61 and 62 are laid on the floor, parallel to the center 5 of the route and symmetrically placed within the width of the transport vehicle 1.

An example of the structure of each of the guiding tapes 61 and 62 is as shown in FIG. Place tape IOA and IOB.

11.12 is a detection device arranged at right angles to the traveling direction on the front lower surface of the truck 1, and 21.22 is a detection device arranged at right angles to the traveling direction on the rear lower surface of the truck 1. The guide tapes 61 and 62 detect the respective positions of the guide tapes 61 and 62 when the trolley 1 travels in the forward direction along the path center 5, while the guide tapes 21 and 22 detect the positions of the guide tapes 61 and 62 when the trolley 1 travels in the backward direction. This is a detection device that detects the respective positions of 61 and 62.

More specifically, this sensing device 11.12.21.2
An embodiment of No. 2 is shown in FIG. 2(b).

That is, for example, the detection device 11 includes a light emitting diode lla as a light emitting source and a beam splitter 11b that reflects the light emitted from the light emitting diode lla toward a reflective tape.
, a photodetector lid that receives the light reflected from the reflective tape, and a lens system 11c. However,
In the present invention, as will be clear from the description below, the image formed on the reflective tape surface and the photodetector has a predetermined width.

The relative position between each detection device 11.21 and each guidance tape 61.62 is as shown in FIG.
Assuming that the width of is W, the detection devices 11 and 21 are arranged in a positional relationship with the guide tape 61 on a line that divides W into W and W2, and the detection devices 12 and 22 are arranged in the same way. It is assumed that WI and W2 are set to be different in dimension. In this embodiment, W is <W2. The reason why Wl and W2 are set differently is that, as shown in FIG.
Since the detection device 11 is located on the non-reflective tape of the guide tape earlier than the guide tape 2, the detection device 11 detects a decrease in the amount of light received earlier, so the detection device 11 detects the decrease in the amount of light received earlier depending on which one detects the decrease in the amount of light received. This is to enable the direction of movement of the object to be detected.

However, the dimensional settings of W and W2 are not limited to this embodiment, and it goes without saying that other cases can also be implemented.

Each of the detection devices 11, 12, 21 and 22 is composed of, for example, a photoelectric sensor, an image sensor-1 optical fiber sensor, etc., and may be a sensor that can irradiate light onto the guide tape and detect the amount of light reflected from the guide tape. Bara (,1
00 is a control device comprised of a circuit that outputs a steering signal and a drive signal based on signals from each detection device, and other predetermined circuits.

FIG. 5 is an explanatory diagram showing the running situation of the automatic guided vehicle,
The trolley 1 travels on the path center 5 in the direction of the arrow as shown in Fig. 5 (A
) shows a situation where the truck 1 is running on the route center 5. In addition, FIG. 5(B) shows that when the truck 1 begins to deviate from the path center 5, the amount of lateral deviation between the path center 5 and the center 8 of the truck 1 becomes X, and the deviation angle becomes θ. The situation is shown below. In this case, the detection of the guide tapes 61 and 62 is performed by the detection devices 11 and 12.

FIG. 6 is a diagram showing details of the situation in FIG. 5(B).

In FIG. 6, the positions 08 of the detection device 11 and 02 of the detection device 12 are the positions 02' of the detection device 11 and 02' of the detection device 12 when the truck 1 is running on the route center 5.
At each position, the deviation amount is X from the path center 5 to the center 8 of the truck 1.
, indicates the position when the deflection angle is θ.

dl indicates the distance between 01' and the non-reflective tape IOA on the right side of the guide tape 61, and d2 indicates the distance between 02' and the non-reflective tape IOB on the right side of the guide tape 62. a is the center distance between the guiding tape 61 and the guiding tape 62, W is the width of the guiding tapes 61 and 62, and Wl is the distance between each sensing device 11 when each sensing device is at the positions Ol and 02.
and 12 and the non-reflective tape IOA on the side of the path center 5 of the guide tapes 61 and 62, and W2 represents the distance from the non-reflective tape IOB on the outside of the path center 5.

FIG. 7 shows the guide tape 6 at the center 0,' of the detection device 11 and the center 02' of the detection device 12 in FIG.
1 and 62. FIG.

FIG. 7(A) shows the guide tape 61 in the detection device 11.
Optical non-reflective tape IOA allows the amount of light received to be Q
Similarly, in FIG. 7(B), the detection device 1 decreases by 1.
2 shows a case where the amount of light received is smaller by Q2IIi. Let r be the radius of the light receiving parts of the detection devices 11 and 12. The intersections between the outer periphery of the light-receiving part of the detection device 11 and the left end of the non-reflective tape IOA are respectively elsfl, and the intersections between the outer periphery of the light-receiving part of the detector 12 and the left end of the non-reflective tape IOH are respectively e.
2, f2. <e, 01 'f1 is 2φ, <
Let e202'f be 2φ2.

In the above case, as shown in Figure 7, dl
°r·cos φ1(1) d2=r'cO3φ2(2) Further, the amount of decrease in the amount of light received by the detection device is as follows.

r-sinφI Xi/2 = r2φ, -r ・d, ・sin ψ, (3) r
-sin φ2
a (1cos θ)−X(51d2 = (
a + W2 )-a ・cos θ-X=W2
+ a (1-cos θ)-X (6) From equations (5) and (6), d, +d, = (Wl +W2) -2X
(71 Therefore, from equation (7), d+ d2 = 2 a cos θ−'l a
(9) Therefore, from equation (9), Wl, W2, and a are predetermined numerical values determined by the relationship between the automatic guided vehicle and the guide tape.

Therefore, equations (8) and α0) can be calculated if dl and d2 are known. Further, when considering equations (11, (2), (3), and (4)), r is the radius of the light receiving part of the detection device, and becomes a predetermined value depending on the detection device.

The decreases Q1 and Q2 in the amount of light received by the detection device are amounts detected by the detection device.

For this reason, d and d2 can be calculated using equations (11 to (4)).For the reasons mentioned above, the deflection amount X of the truck can be calculated from equation (8), and the deviation angle θ can be calculated from equation 00. I can do it.

The steering angle S of the truck at this time can be expressed by the following equation.

To S=, 2 to X+ ・θ (11
) However, K, , K2 are constants.

Therefore, as described above, the amount of decrease in the amount of light received by the detection device 11 Q
By detecting the amount of decrease in the amount of light received by I and the detection device 12, Q2, the amount of deviation X and the deviation angle θ are calculated, and as a result,
The steering angle S of the truck can be calculated, and the steering motor is controlled based on this. The traveling locus of the bogie at this time is shown in FIG. 8, and it converges on the center XO of the traveling route, allowing it to travel smoothly along the traveling route.

In addition, in FIG. 6, the position of the detection device 11 is OI'
, when the position of the detecting device 12 is 0.2'', the above-mentioned case where the position of the detecting device 11 is 0.', the position of the detecting device 12 is 0.2'', and the decrease in the amount of light received by each detecting device Q1
The case where and Q2 are the same is shown. When it is necessary to distinguish between these two conditions, for example, the automatic guided vehicle travels to the position of each detection device shown in FIG. This can be done by storing and calculating in the control device 100 the state of change in which the amount of light received increases or decreases in accordance with the traveling situation of the automatic guided vehicle.

FIG. 9 is a block diagram of the control circuit of this embodiment. Reference numeral 100 denotes a control device that performs calculations and other predetermined controls based on the output from the detection device, and generates steering and running signals. 15 is a detection device section, and in this embodiment, forward motion detection devices 11 and 12, reverse motion detection device 21
and 22, and depending on the direction of travel of the trolley,
When moving forward, detecting devices 11 and 12 are activated, and when moving backward, detecting device 2 is activated.
1 and 22 to detect the guide tape.

2 is a steering wheel, and this steering wheel 2 is connected to a steering motor 134 via a speed reduction mechanism 136. Further, for example, a potentiometer 135 is connected to the shaft of the steering motor 134 in order to detect the steering angle of the steering motor.

Further, 3 and 4 are left and right drive wheels, and the drive motor 124 is connected to the drive motor 124 via a speed reduction mechanism 126 including a differential gear.
Further, an encoder 125 for measuring the rotational speed of the driving wheels is connected to the speed reduction mechanism 126 .

Next, to explain the signal flow, the detection device 1
1 and 12 pass through the forward circuit 111, and the detection devices 21 and 22 pass through the backward circuit 1f2. 101 and stored in advance in the storage device 102, the amount of deviation X of the truck is calculated.
and the deflection angle θ are calculated, and the steering angle and running conditions are determined based on the calculations.

Here, a steering signal from the central processing unit 101 drives the steering wheel 134 via a synchronization circuit 131, a D/A converter 132, and a control circuit 133 to steer the steered wheels 2. The steering angle of the steered wheel is expressed as the output of the potentiometer 135, and this output is fed back to the synchronization circuit 131 via the A/D converter 137, so that the steered wheel can be controlled.

On the other hand, a running signal output from the central processing unit 101 drives a drive motor 124 via a synchronization circuit 121, a D/A converter 122, and a control circuit 123, and passes through a speed reduction mechanism 126 including the differential gear to drive wheels. 3.4 to run the automated guided vehicle.

Further, the rotational speed of the driving wheels is expressed as an output of the encoder 125, and this output is fed back to the central processing unit 101 via the pulse counter 127, thereby stabilizing the control. In addition, the running status of the automatic guided vehicle and the status of changes in the decrease and increase in the amount of light received by each detection device are reported to the central processing unit 101.
It is also possible to store and calculate in the storage device 102.

In addition, by providing a function to divide the light-receiving surface of each detection device into two parts, for example, part 1 and part 2, as shown in Fig. 10, and detecting the parts, each detection device can face the non-reflective tape surface. When the amount of received light decreases, by detecting the amount of decrease in the amount of received light and a signal that distinguishes between the partial force cylinder part and the part where the amount of received light has decreased, the amount of deviation X and deviation of the truck can be determined. The procedure for controlling the steering angle and driving conditions described above for calculating the angle θ can be simplified.

Also, among the guidance tapes shown in Fig. 4 laid on the floor, one of the non-reflective tapes IOA or LOB is marked with a mark that can be distinguished from the other, and each detection device detects the mark. Additionally, the above-mentioned procedure for calculating the steering angle and running conditions for calculating the deflection amount X and deflection angle θ of the bogie can be simplified.

In this embodiment, an example of the structure of the guide tapes 61 and 62 is shown in FIG. 4, but if the floor surface on which the guide tape is laid is an optically non-reflective surface, It is not necessary to install the non-reflective tapes IOA and IOB shown, and it is of course possible to install only the reflective tape 9.

Furthermore, in this embodiment, the arrangement of the respective detection devices is such that detection devices 11 and 12 are used for forward movement, and detection device 21 is used for reverse movement.
Although the arrangement of the detection devices is not limited to this, for example, as shown in FIGS. 11 and 12, and the deviation amount X and deviation angle θ are determined by these two sets.
It is also possible to calculate

Moreover, for each induction tape, in this example, W, <W
2, the dimensional settings of Wl and W2 are not limited to this embodiment, and it goes without saying that other cases can also be implemented.

According to this embodiment, changes in the amount of reflected light are detected using at most four sets of detection devices, two sets each at the front and rear of the automatic guided vehicle, and the amount and angle of lateral deviation from the path are detected. Tono 2
By calculating the elements and controlling the steering angle, it is possible to make the automatic guided vehicle smoothly travel along the travel route using a simple method.

FIG. 12 is an explanatory diagram showing a traveling situation of an automatic guided vehicle according to a second embodiment of the present invention, in which the trolley 1 is located at the center of the route 5.
The diagram shows a situation where the deviation from the top is increased, and the amount of lateral deviation between the path center 5 and the center 8 of the truck 1 is X, and the deviation angle is θ. This embodiment differs from the first embodiment in that one set of guide tape 70 is laid in the center of the path, and the detection devices 81 and 8
2 are arranged on the center line of the guide tape 70 at the center of the truck 1, one set each at the front and rear, for a total of two sets. Here, the configuration of the detection devices 81 and 82 is the same as that of the detection devices 11 and 12 described above. The other structure is the same as that of the first embodiment, and the guide tape 70 is replaced by the guide tape 6 of the first embodiment.
1 and 62 and the respective detection devices 81 and 82 are similar to the detection devices 11, 12, 21 and 23 of the first embodiment. 7
1 indicates a reflective tape, and 72 indicates a non-reflective tape.

In FIG. 12, the position of the detection device 81 and the position of the O3 detection device 82 are 0□', the distance between the detection devices 81 and 82 in the traveling direction of the trolley 1 is the same, and the distance between the center of the guide tape 70 and the non-reflective tape on both outer sides is 0□'. Let W be the distance from 72.

dl is the distance between O+' and the non-reflective tape 72 on the right side of the guidance tape 70, and d2 is the distance between 02' and the guidance tape 70.
The distances to the non-reflective tape 72 on the left side are shown respectively.

FIG. 13 is a diagram showing the detailed state of the detection devices 81 and 82 in FIG. 12 with the guide tape 70. 13th
Figure (A) shows the state of the detection device 81 and the guide tape 70.
FIG. 13(B) is a diagram showing the state of the detection device 82 and the guide tape 70. Let X be the distance between the respective centers of the detection devices 81 and 82 in the traveling direction.

The amount of lateral deviation X of the truck 1 is It is.

In the above case, as is clear from FIG. 13, the detection devices 81 and 82 are
Let r be the radius of the light-receiving part of
2, d,=r-cos φ, (21)
d2=r-cos φ, (22)
Ql-r2φ, -rd, sin φ, (23)
Q2=r2φ2−rd2sinφ2 (24)
Furthermore, as is clear from FIG. 12, since X=X,/2. Therefore, in the same procedure as explained in the first embodiment, (21) to
Using equation (24), d and d2 can be calculated, and from equation (25), the deviation angle θ can be calculated from equation (26), which is the amount of deviation
can be calculated.

The steering angle S of the bogie at this time was explained in the first embodiment (1
Since it is the same as formula 1), by detecting the amount of decrease Q in the amount of light received by the detection device 81 and the amount Q2 of decrease in the amount of light received by the detection device 82, the amount of deviation X and the deviation angle θ are calculated, and the result is By being able to calculate the steering angle S of the truck and controlling the steering motor based on this, the truck can travel smoothly along the travel path as shown in FIG.

The block diagram of the control circuit in this embodiment is as follows.
This embodiment is the same as FIG. 9 shown in the embodiment except that there are two sets of detection devices, so a description thereof will be omitted. The same applies to the flow of signals. Furthermore, as shown in Fig. 1θ in the first embodiment, by dividing the light receiving surface of each detection device into two equal parts, the procedure for controlling the steering angle and running conditions described above can be simplified. It is possible as well. Also, regarding the configuration of the guide tape 70 in this embodiment, if the floor surface on which the guide tape is laid is an optically non-reflective surface, there is no need to lay the non-reflective tape 72 shown in FIG. Of course, it is possible to do this by laying only the tape 71.

According to this embodiment, regardless of the traveling direction of the automatic guided vehicle, by simply arranging one set of detection devices at the front and rear, changes in the amount of reflected light can be detected, and the lateral deviation from the path and the deviation angle can be detected. By calculating the two factors and controlling the steering angle, it is possible to make the automatic guided vehicle run smoothly along the travel route using a simple method.

In addition, in any of the embodiments, when the unmanned+III vehicle is traveling, ■ When the vehicle deviates from the travel route ■ When the guidance tape is damaged for more than a predetermined distance or the reflective tape surface is dirty and the amount of reflected light decreases ■ The guidance tape In other cases, such as when the detection device does not detect the guidance tape for a predetermined period of time, the central processing unit 101 of the control device 100 in FIG. If the tape is not detected, a circuit may be provided to bring the automated guided vehicle to an emergency stop.

In addition, as shown in FIG.
For example, guide tape and other emergency stop tapes 63 and 64 are laid on the outside of the guide tape and 62, and these emergency stop tapes 63 and 64 are detected by a detection device installed on the truck, and the detection signal causes the truck to stop. It is also possible to provide a circuit that causes an emergency stop when the vehicle deviates from the travel route. The emergency stop tapes 63 and 64 may be of any type as long as they can be detected by the detection device.

In this embodiment, the shape of the light-receiving surface of each detection device is circular, but the shape of the light-receiving surface is not limited to this, and may be any shape as long as it can detect changes in the amount of light received.

Further, in this embodiment, although the number of drive motors has been explained as one, a two-wheel drive type with two drive motors may be used.

(F) Effect According to the present invention, the amount of lateral deviation from the path and the deviation angle can be determined by simply detecting the change in the amount of light reflected from the guide tape using the detection device installed on the automatic guided vehicle. Since the steering angle is controlled by calculating two elements, even if the automated guided vehicle deviates from the route, the steering can be corrected using a simple method and the vehicle can be quickly returned to the route, allowing for uncentered transportation. This has the effect of allowing the vehicle to run smoothly without meandering.

[Brief explanation of drawings]

FIG. 1 is a plan view showing the running relationship of an automatic guided vehicle according to a first embodiment of the present invention, and FIG. 2 (al is a side view thereof,
FIG. 2(b) is an explanatory diagram showing a specific example of a detection device installed in an automated guided vehicle. FIG. 3 is a diagram showing a traveling trajectory of an unmanned general transportation vehicle in a conventional example. FIG. 5 is a plan view of an example of the structure of the guiding tape.
An explanatory diagram showing the traveling situation of the automatic guided vehicle according to the first embodiment of the present invention. FIG. 6 is a diagram showing details of the situation in FIG. 5(B). FIG. 7 is a diagram showing the detection device in FIG. FIG. 8 shows the detailed state of the guide tape and the guide tape according to the first embodiment of the present invention. FIG. 9 shows the traveling trajectory of the automatic guided vehicle according to the first embodiment of the present invention. FIG. 10 is an explanatory diagram when the light-receiving surface of each detection device of the first embodiment of the present invention is divided into two. FIG. 11 is a block diagram of the detection device of the first embodiment of the invention. FIG. 12 is an explanatory diagram showing a traveling situation of an automatic guided vehicle according to a second embodiment of the present invention. FIG. FIG. 14, which shows a detailed state, is an explanatory diagram in the case where an emergency stop tape is laid separately from the guide tape for the travel route according to the present invention. l... Trolley (automated guided vehicle), 2... Steering wheel, 3.4
... Drive wheel, 5 ... Center of travel path, 61.62.
70... Guidance tape, 63.64... Emergency stop tape, 11.12.21.22.81.82... Detection device, 100... Control device.

Claims (4)

[Claims] (1) In an automated guided vehicle equipped with a guidance tape laid on a floor surface, and a steering device and a traveling drive device that detect the position of the guidance tape and automatically follow the guidance tape along a travel route, the guidance tape a detection device for detecting the amount of light reflected from the guiding tape by applying a light source to the guiding tape; a means for calculating a deflection and a deflection angle of the vehicle body based on a signal from the detection device; and a means for calculating a steering signal based on the calculation means. and a control device that outputs a drive signal. (2) Each set of guide tapes has an optically reflective tape in the center and non-reflective tapes on both sides of the optically reflective tape. Guidance device for the automatic guided vehicle described above. (3) The detection device is characterized in that the control device is provided with a circuit that automatically stops the automatic guided vehicle when the guiding tape cannot be detected for a certain period of time while the automatic guided vehicle is traveling. A guidance device for an automatic guided vehicle according to item 1. (4) Means for laying an emergency stop tape for the automated guided vehicle parallel to the travel route on both outsides of the guide tape, detecting the emergency stopping tape with a detection device, and causing the automated guided vehicle to make an emergency stop based on the detection. A guiding device for an automatic guided vehicle according to claim 1, further comprising: