JPS61202208A - Guiding method for unmanned truck at branch line - Google Patents

Abstract

PURPOSE:To avoid the misdrive of an unmanned truck by setting the photodetecting quantity received by a photoreceptor set at a place immediately before a branch line in the direction opposite to the traveling direction of the truck at zero regardless of the actual photodetecting quantity and then releasing this state immediately after the truck passed through the branch line. CONSTITUTION:An unmanned truck 1 consists of a drive wheel 3 which has steering revolutions by a drive motor M1 and a steering device 6 containing a sprocket 4 and a steering motor M2 coupled to the sprocket 4. In a branch control mode the value given from a phototransistor (TR)17 set at he right or left side of a sensor 7 is set at O regardless of the actual voltage after a branch mark 40 is detected. When the truck 1 is branched to the left, for example, the actual value of the TR17 of the right side is high at the position Y. Then the center P3 of a guide line 12a is detected at the left side of the sensor 7 since the value of the TR17 is set at O. Thus the truck 1 is steered to the left. This state is released after the truck 1 passes through a point T.

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention relates to an unmanned vehicle installed in a warehouse or factory for the purpose of transporting goods. This invention relates to an unmanned vehicle that guides the vehicle while detecting guidelines using an optical sensor.

<Conventional technology> For example, unmanned vehicles (hereinafter simply referred to as unmanned vehicles) in factories
When adopting a transportation system in which goods are transported by unmanned vehicles, the travel route often has many branching points, and the desired route is selected from the numerous travel routes formed by the branching points. The driverless car is running selectively. In this respect, unmanned vehicles are superior to conventional transportation means such as conveyors and trolleys that run along rails, and the introduction of unmanned vehicles will make transportation within the factory more streamlined. I'm making it flexible.

Conventionally, the method for guiding an unmanned vehicle using an optical guidance method at a branch road is to receive a branch signal just before the branch point, and if the signal indicates ``go right'', the vehicle steers to the right at a predetermined angle and runs. If you want to "go left", there is a method of steering the vehicle to the left by a predetermined angle. □ ≦Problem to be solved by the invention
If j) is only "r straight ahead", the unmanned vehicle can only branch in the same direction at any branch point. Branching □S5
Te: If information about the degree of negative alignment was also given to the unmanned vehicle, the structure of the control unit of the unmanned vehicle would become complicated.

In addition to the above methods, conventional branching.

Among the many ways to guide people, the first one is in front of the crossroads. .

The guideline-following guidance method that has been used so far =
In addition, the system was complicated because it involved a lot of work, such as branching using the guidance method for the nine-branch branch, and then re-adopting the guideline following type method after passing the branch point.

The present invention provides guidance for unmanned vehicles at branching roads in a very simple manner, and is capable of guiding unmanned vehicles even in systems with many branching points.

<Means for solving the problem> In this invention, the value of the amount of light received by the light-receiving element opposite to the traveling direction immediately before the branch road is taken as a zero value regardless of the actual amount of received light, and Immediately after, the value of the received light amount set to zero is canceled.

<Made by, 1. For> 5 1. ．． 1. The unmanned rate is 5 of the guideline in the advancing φ direction.
1. Run along the line.

Example of implementation〉1. , Figure 2 shows a three-wheeled vehicle as an example of an unmanned vehicle.
1), this unmanned vehicle is composed of the following elements.

Drive wheel (3), which is directly connected to the travel motor (Ml) and rotates around the vertical axis (2) through pre-tearing;
A steering motor (M
2) Steering device (6) consisting of vertical axis (2)
It rotates in synchronization with the drive wheel (3), has a light source and a light receiving element inside, and detects the guideline (12).
Control #J device (C) with built-in 1"'5'> m,
Battery (Ba), driven wheel (8) (8), - Operation part (101) installed above the rear end i4 of the unmanned vehicle and to which the top surface number J4;6 and the operation panel (9) are fixed.゜Next, the second guideline senna (9) (hereinafter, a large number of holes (14) in two rows in the hand direction (1'5)Q?j'5?-1
:'::tm near 'M(D'=%:'/l, "j":
A phototransistor (1'7) as a light-receiving element is inserted into the other aligning hole (1'4-'). ) (18) is the front mounting plate for unmanned vehicles. Tsuku, (
,・19) "Ima Prirae Ice Substrate (21) is a red film layer. □ ゛□゛Figure 6 shows the above infrared light die (16) and phototransistor (17). The circuit is shown and light (L) is generated by applying voltage (V'ti).
is emitted, reflected light from the floor surface or guideline enters the phototransistor (17), and a voltage approximately equal to the amount of incident light is output (OUT□.). □In this way, the output voltage from each phototransistor (17) changes almost in proportion to the amount of direct radiation from the phototransistor (17), and the magnitude of the output voltage varies. 1 to indirectly detect the difference in the light reflectance of the floor surface, that is, whether the floor surface is a guideline or not.
Ru. □゛□Figure 7 is a block diagram showing the connections of the computer, sensors, etc. on the one-person vehicle, and each phototransistor (17') is connected to an analog multiplexer (22), a multiplexer (23): A /D converter (24
) was mounted on the car body (1) through the
The controllers (25) are connected to the traveling motor (M''1) and the steering motor (M2) through interfaces (2'6) and (2'I)', respectively.
), and the output signal of the phototransistor (17) is connected to the computer (25) using a method described in detail later.
) performs arithmetic analysis to calculate the guideline position, and based on the calculated value, the travel motor (Ml) or steering motor (M2) is appropriately driven to perform guided travel.

(31), (32), and (33) are computers (25) respectively.
RAM, CPU, and ROM inside.

That is, the multiplexer (22) is appropriately switched by the phototransistor selection command (29) from the computer (25), and the phototransistor (
The output voltages from 17) are sequentially input to the A/D converter, and the output voltages are converted into corresponding digital values and stored in the RAM (31) in the computer (25).

The stored voltage values are processed as follows.

That is, when the stored voltage value, that is, the amount of light received is expressed in a bar graph, it becomes a bar line with white circles in FIG. 9, and the numbers on the horizontal axis of the graph indicate the position of each phototransistor (see FIG. 8). The vertical axis shows the amount of light received, but the bar line with white circles is a value based on the actual amount of light received, so it does not faithfully reflect the effects of locally bright areas on the floor, highly reflective dust, etc. , even in areas other than the guideline may show a locally high value (the 14th value in Figure 9).In order to eliminate this influence, the voltage value obtained in the above manner is
First, smooth it as follows.

That is, as shown in FIG. 9, the actual voltage values from the first and sixteenth phototransistors, that is, the transistors at both ends of the sensor, are each detected to be 1.5 volts. The values from the phototransistors (17) at both ends are 1
The actual voltage values from the inner phototransistors (No. 2 and No. 15) are compared with each other, and the smaller value is taken as the smoothed voltage value at each end. For example, the first and second
When the actual voltage values of the first voltage are compared, the first value is smaller, so the first smoothed voltage value becomes the first actual voltage value.

In addition, to smooth the voltage value of each phototransistor (17) No. 2 to No. 15, compare the values on both sides and the three voltage values, and select the second largest value as the smoothed voltage value of the phototransistor (17). voltage value. For example, the 14th smoothed voltage is the second largest value when comparing the 13th to 15th values, that is, the 13th value.

The above calculation is performed for each phototransistor to smooth all values.

The smoothed values are shown as bars with black circles in FIG.

Next, each phototransistor (1
From all the smoothed values for 7), an appropriate threshold value (T
Set.

As is clear from Figure 8.9, the actual voltage values (white circles) before smoothing are at the guideline positions (5th to 8th).
There are values that exceed the strict value m at other phototransistor positions (No. 14), but after smoothing, only the values of the phototransistors at the guideline position (No. 5 to 8) exceed the strict value ('11). First, the guideline position can be accurately detected.

Then, the center of the guideline is determined based on the critical value mark determined by the above calculation and each value after smoothing.

That is, based on the above-mentioned smoothing value and threshold value (T), for each phototransistor (No. 1 to 16), the smoothed value exceeding the threshold value (Tl is "1").
Then, binarization is performed (Figure 10) in which those that do not exceed the critical value (T are set to "0"). For example, in the above example, the phototransistors 1 to 4 and 9 to 1
rOJ is given to 7), and "1" is given to the 5th to 8th phototransistors (17).

Then, 1 is added to each phototransistor (Nos. 1 to 16) to the value M “0” or “1” given by the above binary conversion.
(in other words, a number that increases as you go from the leftmost edge to the rightmost edge, in this example, O
~30), and the value of the product is divided by the sum of all values after binarization.Thus, the center of the guideline is found.8 In other words, in the case of the above example, the 10th
As shown in the figure, the first phototransistor (17
), rOJ is the second phototransistor (17)
, "2" is given as the position weight W, and "30" is given as the position weight W to the 16th phototransistor (17), and the center position of the guideline is determined as follows. Bone calculated as position/position weight.・ Σ (position weight) × (value after binarization) Σ (value after binarization) (OXO) + (2XO) +・+ (8X1) + (IOXI
) + (1 to 12) Therefore, in the above example, the center of the guideline is placed at the point where the position weight is "11", that is, the center of the guideline is directly below the midpoint between the 6th and 7th phototransistors in the sensor (7). is detected.

As mentioned above, depending on the total sum of (position weight) x (value after binarization) divided by the sum of (value after binarization), Since the sum corresponds to the width of the guideline, the center position of the guideline can be detected accurately and is not eliminated by the smoothing process described above.

``The impact of locally high state taxes can be reduced.'' .

・From 1′, as above, then set up the computer (″・
Once the center position of the guideline has been calculated in 2.5), then the center position of the guideline is calculated as follows: -171: -(for 71)
Depending on the direction of deviation in the guide line position, the Z1 steering motor (M2) is rotated in the direction to correct the deviation, either left or right. Next, the unmanned vehicle at the branch point The guidance method for the driver will be explained based on Fig. 1.If the sensor (7) points out the branch mark (40) once, the unmanned vehicle will move to the branch mark (40).
, 40) after a distance (ψ travel): After that, it travels in the fixed direction.In addition, (12a) (12b)
indicates a fork in the road.

That is, the value given by the binarization of the right phototransistors (Nos. 10 to 16) after traveling the distance Td) after detecting the branch mark (40) □ to the junction passing point ■. M is given rOJ regardless of its actual voltage value. The value given by the binarization of the phototransistors (Nos. 1 to 7, .) on the left side, Q, which detects the mark for branching/branching to the right. M is 1. , Part 1 ('O' is given). Information regarding the above value M is stored in the RAM (31) or ROM (33) in the computer (25). ,
After branch mark detection, the data is sent to the CPU (32). ,: Now, in Figure 1, 1. , 2: The 17-ototransistor (17) whose value M given by value conversion is "1" is shown by a black circle -1: , ) The above value M is .

7 of rOJ. Odotransis, ri (17) is indicated by a white circle. The dot-dash lines (Pt) to (P3) indicate the center of the detected guideline at each position.

Note that the smoothing, binarization, and guideline center position calculation methods are the same as those described above.

After traveling distance (d) from the branch mark (40), the value M of phototransistor No. 10 is rOJ, so the center of the guideline (P2) is slightly to the left of the center of the sensor (7). When detected, the unmanned vehicle will turn the steering wheel to the left. At position ('Y), the 12th to
The actual voltage value of phototransistor No. 16 is high or low (■ is "0", so it is at the center of the guideline (P3
) is detected to be the left side of the sensor (7), and the unmanned vehicle continues to turn the steering wheel to the left. After passing through the branching point m, the phototransistors on the right (10th to 1st
The fixation of the value M of No. 6) to "0" is released, and normal detection is performed.

Note that in the above explanation, the value M of the No. 8 and No. 9 phototransistors was set so as not to be fixed to "0", but for example, the value M of the No. 1 to No. 8 phototransistors is
) is defined as rOJ when it branches to the right, and similarly, the 9th to 1st
If the value M of number 6 is a leftward branch! This may be set to "0".

Furthermore, although the above-mentioned fixing to "0" is performed at the stage of binarization, for example, at the stage of issuing a phototransistor selection command (29) from the computer (25), a command is issued not to operate a desired multiplexer (22). (29) may be issued.

<Effects of the Invention> As explained above, according to the present invention, an unmanned vehicle can be guided at a branching road in a very simple manner.
Moreover, the branching method does not involve adopting a new branching guidance method at the branching road, but instead employs a guideline following method for areas other than branching points, so there is no need to add new equipment. Further, according to the present description, it is possible to completely eliminate erroneous driving at branch points.

[Brief explanation of drawings]

FIG. 1 is a schematic plan view for explaining the branch guidance method for an unmanned vehicle at a branch road according to the present invention, FIG. 2 is a schematic plan view showing an example of an unmanned vehicle, and FIG. 3 is an optical sensor The plan view and Figure 4.5 are the cross-sectional views taken along line A-A and B-B in Figure 3, respectively.
Line cross-sectional view, Figure 6 is a circuit diagram, Figure 7 is a block diagram showing the connection of the computer, optical sensor, etc. on the unmanned vehicle, and Figure 8 is the positional relationship between the phototransistor of the optical sensor and the guideline. Figure 9 is a bar graph showing the actual amount of light received by each phototransistor and the value after smoothing. Figure 10 is a schematic diagram showing the position weight and binarized value for each phototransistor. be. (1)... Unmanned vehicle (7)... Optical sensor (12)... Guideline (12a) (12b)... Guideline branch path (17)... Light receiving element

Claims (1)

[Claims] Optical sensor provides floor guidelines Unmanned vehicles that guide the vehicle while detecting A guidance method at a crossroads, just before the fork. Amount of light received by the light receiving element opposite to the direction of travel Let the value of be zero regardless of the actual amount of light received, The amount of light received was set to zero immediately after passing through the branch road. Unmanned vehicle characterized by releasing value Guidance method at branching roads.