JPS6248265B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a mark or barcode reading device.

In general, in unmanned vehicles that can automatically travel along a predetermined track, a bar code consisting of a series of bar signs is pasted on the floor so that the unmanned vehicle can detect location information while traveling. , a method is adopted in which an unmanned vehicle reads this mark (barcode) and detects its location information.

Conventional mark reading methods include a parallel reading method, a serial reading method, and a serial reading method such as a timing bit method. Among these, the parallel reading method uses multiple detectors to detect the presence or absence of bars at once by arranging the bars in a direction perpendicular to the direction of movement of the unmanned vehicle, and reading the bar presence/absence information. This method requires the same number of detectors as the number of bits in the barcode, which has the disadvantage of being expensive. In addition, the serial reading method arranges bars in the direction of movement of the unmanned vehicle, detects the bars in series with one detector, counts the number of detected pulses, and reads information from the count value. However, this method required many circuits such as a scan circuit, a pulse generating circuit, and a counting circuit, making the device complex and expensive. Furthermore, in the timing bit type serial reading system, for example, two detectors are mounted on an unmanned vehicle in a direction perpendicular to the direction of movement of the vehicle, and at the timing when one detector detects a bar, the other detector reads the bar. This method reads information by detecting its presence or absence, but this method has the disadvantage that errors in the direction of movement can sensitively affect reading accuracy.

Therefore, the inventor of the present invention proposed a mark reading method that eliminates the above-mentioned drawbacks by arranging first and second bars of different widths in the direction of movement of the moving object, and placing the first and second detectors in the direction of movement of the moving object. A third detector is arranged between the first and second detectors, and the first detector detects one end of the bar in the width direction, and the third detector is arranged between the first and second detectors. We have already developed a system that determines the type of bar according to the output of the second detector when the third detector detects the presence of a bar, and outputs the binary information of the mark as parallel information. There is.

By the way, in the conventional mark reading method, when trying to detect whether reading of a mark has been completed, a mark is separately provided to indicate the completion of reading, and a logic circuit is used to distinguish between this mark and an information mark. The conventional method is to detect the completion of reading, or to provide a dedicated detector to detect the completion mark of reading. However, this method requires a mark other than the information mark, and also requires a complicated logic circuit and a new detector.

This invention was made in view of such conventional problems, and in the above mark reading method developed by the inventor of the present invention, all of the first, second, and third detectors detect the presence of a bar. mark reading is completed when the first and second detectors stop detecting the presence of the first bar. It is an object of the present invention to provide a mark reading device that can accurately and easily detect the completion of mark reading with a simple configuration by generating a signal.

Embodiments of the present invention will be described below with reference to the drawings. 1 to 4 show a mark reading device according to an embodiment of the present invention. In the figure, 1 is a road surface which is an object to be detected, and a bar code (mark) 3 formed by encoding positional information is pasted on the road surface 1. Reference numeral 2 denotes an unmanned carrier (moving object) that travels on the road surface 1 in the direction of arrow A. When the carrier 2 passes over the mark 3, the mark 3 is read to determine its position. The mark 3 above is the first bar of width a ₁ (meaning binary “0”) and the width a ₂
(a ₂ > a ₁ ) and the second bar (meaning binary "1") are arbitrarily arranged at intervals b, and in the examples in Figures 3 and 4. 4 and 5 are the first
The bar 6 is the second bar. Note that each of these bars is formed using a reflecting plate.

On the other hand, a detection device 7 is disposed on the bottom surface of the transport vehicle 2, and the detection device 7 includes a first light receiving sensor (first detector) 8 that detects one end of the bar in the width direction and detects the presence or absence of the bar. It is composed of second and third light receiving sensors (second and third detectors) 9 and 10. The detection position 9a of the second light receiving sensor 9 on the road surface 1 is set at a distance d from the detection position 8a of the first light receiving sensor 8 in the direction of arrow A, that is, in the width direction of the bar. The detection position 10a of the third light receiving sensor 10 is set at a distance e from the detection position 8a of the first light receiving sensor 8 in the width direction of the bar. However, here e<a ₁ <d<a ₁
+b, e<b<d<a ₂ . Also, the above transport vehicle 2
is provided with a light emitting element (not shown) that emits light downward, and is also provided with a reading circuit and a reading completion signal generating circuit (see Fig. 5), and the reading circuit is a first light-receiving circuit. The sensor 8 detects one end of the bar in the width direction, and the third light receiving sensor 1
0 detects the presence of a bar, depending on the detection signal of the presence or absence of a bar from the second light receiving sensor 9, the first light receiving sensor 8 detects whether the bar is the first or second bar. and outputs the binary information of the bar as parallel information. Further, the reading completion signal generation circuit receives the outputs of the first, second, and third light receiving sensors 8, 9, and 10, and all of the three light receiving sensors 8, 9, and 10 no longer detect the presence of the bar. When the second and first light-receiving sensors 9 and 8 first start detecting the presence of a bar, only when the first and second light-receiving sensors 8 and 9 respectively stop detecting the presence of a bar. A mark reading completion signal is generated.

Further, FIG. 5 shows the detailed circuit configuration of the reading circuit and the reading completion signal generation circuit, and in the figure,
8, 9, and 10 are the above-mentioned first, second, and third light receiving sensors. 11 is the output a of the first light receiving sensor 8
12 receives an inverted signal of the output a of the first light-receiving sensor 8, and generates a pulse signal f when the output a of the sensor 8 rises; 8
A second pulse generating circuit 13 is composed of a monostable multivibrator that generates a pulse signal g at the falling edge of the output a. A first AND circuit 14 having two inputs is a second AND circuit having two inputs: the output g of the second pulse generating circuit 12 and the output c of the third light receiving sensor 10.
15 is the first pulse generating circuit 11 and the first AND
A first direction determining circuit 13 is configured to determine whether the moving direction of the transport vehicle 2 is the forward direction;
This is a second direction determining circuit configured with an AND circuit 14 and determining whether or not the moving direction of the transport vehicle 2 is the backward direction.

17 is an OR circuit having two outputs from the first and second direction discrimination circuits 15 and 16, and 18 is an OR circuit 1.
A third pulse generating circuit 19 is composed of a monostable multivibrator which receives the output of 7 and generates a pulse signal when the output of the circuit 17 rises; 19 is constituted by an OR circuit 17 and a third pulse generating circuit 18; This is a clock generation circuit that generates a clock signal CK from the outputs of the two direction discrimination circuits 15 and 16 that is synchronized with the discrimination outputs.

Further, 20 and 21 are 4-bit bidirectional shift registers (sequential storage elements), and the So terminal, _S1 terminal, and CK terminal of both shift registers 20 and 21 are connected to the output of the first AND circuit 13 and the output of the first AND circuit 13, respectively. 2 of
The output of the AND circuit 14 and the output of the clock generation circuit 19 are added to the R terminal of the shift register 20 and the L terminal of the shift register 21.
The output D ₄ of the least significant digit of the shift register 21 is input to the L terminal of the shift register 21, and the output D ₃ of the most significant digit of the shift register 20 is input to the R terminal of the shift register 21. 22, when receiving the direction discrimination signal from the first or second direction discrimination circuit 15, 16, sets the second direction in the least significant digit or the most significant digit according to the clock signal from the clock generation circuit 19. A serial/parallel conversion circuit 23 is composed of the shift registers 20 and 21 for reading the output of the light receiving sensor 9, and is composed of the first and second direction discrimination circuits 15, 16, the clock generation circuit 19, and the serial/parallel conversion circuit 22. This is a reading circuit.

Further, 24 is a first, second, and third light receiving sensor 8,
An OR circuit which takes the outputs a, m, and c of 9 and 10 as three inputs; 25 receives the output m of the second light receiving sensor 9;
A fourth pulse generation circuit 26 consisting of a monostable multivibrator that generates a pulse signal h in synchronization with the rise of the output m receives an inverted signal of the output m of the second light receiving sensor 9 and generates a pulse signal h of the light receiving sensor 9. Output m
A fifth pulse generating circuit 27 consisting of a monostable multivibrator that generates a pulse signal i in synchronization with the falling edge of , receives the output of the OR circuit 24 and generates a pulse signal j in synchronization with the rising edge of the output. A sixth pulse generating circuit 28 consisting of a monostable multivibrator receives an inverted signal of the output of the OR circuit 24 and generates a pulse signal k in synchronization with the fall of the output of the circuit 24. This is a seventh pulse generation circuit.

29 is a third AND circuit whose two inputs are the output of the second pulse generation circuit 12 and the output of the seventh pulse generation circuit 28; 30 is the output of the fifth pulse generation circuit 26 and the seventh pulse; A fourth AND circuit 31 has two inputs of the output of the generation circuit 28, and a fifth AND circuit 31 has two inputs of the output of the first pulse generation circuit 11 and the output of the sixth pulse generation circuit 27.
AND circuit; 32 is a sixth AND circuit having two inputs: the output of the fourth pulse generating circuit 25 and the output of the sixth pulse generating circuit 27; 33 is the fifth or sixth AND circuit;
34 is a seventh flip-flop circuit whose two inputs are the output of the fourth AND circuit 30 and the output of the flip-flop circuit 33. , 35 is the third AND circuit 2
9 and the Q output of the flip-flop circuit 33 as two inputs; 36 is the seventh AND circuit;
The OR circuit 37 has two inputs as the output of the eighth AND circuit 35, and the output of the sixth pulse generating circuit 27 and the external reset signal 37a as two inputs.
An OR circuit, 38 is a flip-flop circuit whose S terminal is connected to the output of the OR circuit 36, and its R terminal is connected to the output of the OR circuit 37, and 39 is a read completion signal generation circuit configured as described above. .

Next, the general operation of this device will be explained using FIGS. 3 and 4.

When the carrier vehicle 2 is traveling on the road surface 1, its light emitting element always emits light downward, and when the carrier vehicle 2 travels in the direction of arrow A, that is, in the forward direction, and passes over the mark 3, the light emitting element always emits light downward. 1 to 3rd light receiving sensor 8 to 10
sequentially receives reflected light from bars 4 to 6 of mark 3. Then, the first light receiving sensor 8 is connected to the first bar 4.
When the starting edge 4a of the third light receiving sensor 1 is detected, the third light receiving sensor 1
Since the detection position 10a of 0 is set as e _{<a 1, it is on the bar 4, and the sensor 10 detects the presence of the bar 4, while the detection position 9a of the second light receiving sensor 9 is set as d>} a Since it is set to ₁ , it has already passed the long end 4b of the bar 4, and the sensor 9 does not detect the presence of the bar, so this bar 4 is determined to be the first bar by the reading circuit. Similarly, regarding the bar 5, when the first light receiving sensor 8 detects the starting end 5a of the bar 5, the third light receiving sensor 10 detects the presence of the bar 5, and the second light receiving sensor 9 detects the presence of the bar 5. Since the presence of the bar 5 is not detected, the bar 5 is also determined to be the first bar by the reading circuit. Furthermore, since the width a ₂ of the bar 6 is set as a ₂ >d, when the first light receiving sensor 8 detects the starting end 6a of the bar 6, the second and third light receiving sensors 9 and 10
The detection positions 9a and 10a are both on the bar 6, and both sensors 9 and 10 detect the presence of the bar 6, so the bar 6 is determined to be the second bar by the reading circuit. In this way, the binary position information of the mark 3 consisting of a plurality of bars can be sequentially read, and the reading circuit outputs the results as parallel information.

When reading the position information of the mark 3 in this way, the distance d between the first and second light receiving sensors 8 and 9 is d>b, and the first and third light receiving sensors 8 and 10
Since the interval e is set as e<b, e<a ₁ , the first, second and third light receiving sensors 8, 9, 1
0 always detects the presence of the bar, and in this case, the second light receiving sensor 9 has started to detect the presence of the first bar, so the reading completion signal generation circuit 39 detects the presence of the first bar. , the second and third light receiving sensors 8, 9, 10 no longer detect the presence of the bar, and the first light receiving sensor 8
generates a mark reading completion signal when it finally fails to detect the presence of a bar.

The mark 3 can also be read when the transport vehicle 2 travels in the direction opposite to direction A, that is, in the backward direction. In this case, the first light receiving sensor 8 detects one end of the bar, and the third light receiving sensor The type of bar is determined according to the output of the second light receiving sensor 9 when the bar 10 detects the presence of the bar. At this time, the reading completion signal generation circuit 39 detects when any of the first, second, and third light receiving sensors 8, 9, and 10 no longer detects the presence of the bar, and in this case, the first light receiving sensor 8 has started to detect the bar for the first time, so when the second light receiving sensor 9 finally stops detecting the presence of the bar, it generates a mark reading completion signal.

Next, the operation will be explained in detail using FIGS. 5 and 6. Here, FIGS. 6b to 6r are timing charts of this device based on the detection timing of the second light receiving sensor 9 when the carrier vehicle 2 runs in the direction of arrow A on the mark 3 shown in FIG. 6a. Yes, mark 3 has binary information of "01001010".

The transport vehicle 2 travels in the direction of the arrow, that is, in the forward direction,
When passing over the mark 3 from the bar of the most significant digit (MSB) to the bar of the least significant digit (LSB), the second light receiving sensor 9 detects the presence of the bar and determines the width a ₁ , a of each bar. ₂ (see FIG. 6b), and the third and first light receiving sensors 10 and 8 similarly generate detection signals c and a corresponding to the widths a ₁ and a ₂ of each bar. This occurs with a delay of a time corresponding to the distance from the second light-receiving sensor 9 (see FIGS. 6c and d). The first pulse generating circuit 11 receives the output of the first light receiving sensor 8, generates a pulse signal f in synchronization with the rising edge of the detection signal a (see FIG. receives the inverted signal of the output of the first light receiving sensor 8, generates a pulse signal g in synchronization with the fall of the detection signal a (see Fig. 6h), and
The AND circuit 13 ANDs the output f of the first pulse generating circuit 11 and the detection signal c of the third light receiving sensor 10, while the second AND circuit 14 ANDs the output g of the second pulse generating circuit 12. AND is taken with the detection signal c of the third light receiving sensor 10. Now that the transport vehicle 2 is traveling in the forward direction, the first
The AND circuit 13 generates the pulse signal FP (see Figure 6l), the output of the second AND circuit 14 remains at "0" (see Figure 6m), and the clock generating circuit 19 generates the pulse signal FP (see Figure 6l). A clock signal CK is generated in synchronization with the rising edge of the pulse signal FP of the AND circuit 13 (see FIG. 6n).

Then, in the serial-to-parallel conversion circuit 22, since the pulse signal FP of the first AND circuit 13 is applied to the So terminals of the shift registers 20 and 21, one shift register 20 receives the second pulse signal input to its R terminal. The clock signal of the clock generation circuit 19 which applies the output of the light receiving sensor 9 to the CK terminal.
Read it at the timing of CK and convert it to the least significant digit D ₀
Then, the other shift register ₂₁ reads the output of the most significant digit _D3 of the shift register 20, which is input to its R terminal, at the timing of the clock signal CK. Then shift it from D ₄ to D ₇ .
Therefore, when the first to third light receiving sensors 8 to 10 detect the bar of the least significant digit of the mark 3, that is, when the mark 3 has been read, the output terminals D ₇ to _{D 0} of the serial/parallel conversion circuit 22 are Parallel information of “01001010” will be output.

On the other hand, in the reading completion signal generation circuit 39, the fourth pulse generation circuit 25 receives the output m of the second light receiving sensor 9 and generates a pulse signal h synchronized with the rise of the output (see FIG. 6e). , the fifth pulse generating circuit 26 receives the inverted signal of the output m of the second light receiving sensor (9), and generates a pulse signal i synchronized with the fall of the output m of the second light receiving sensor (9). Also
The OR circuit 24 receives the outputs of the first, second, and third light receiving sensors 8, 9, and 10, and receives the outputs of the second light receiving sensor 9.
becomes "1" when it starts to detect the presence of the first bar (MSB) (see Figure 6i), and the sixth pulse generating circuit 27 receives the output of the OR circuit 24 and synchronizes with the rise of the output. A pulse signal j is generated (see FIG. 6 j) and applied to the fifth and sixth AND circuits 31 and 32. Then, the sixth AND circuit 3
2 takes the AND of both outputs of the fourth and sixth pulse generation circuits 25 and 27, and outputs the flip-flop circuit 33.
A pulse signal is applied to the terminal of the flip-flop circuit 33 (see FIG. 6o), the Q output of the flip-flop circuit 33 becomes "1" (see FIG. 6g), and the output becomes "0".

And when all the readings of mark 3 are completed,
The output of the OR circuit 24 becomes "0" (see Figure 6i), and the seventh pulse generating circuit 28 generates a pulse signal k in synchronization with the fall of the output of the OR circuit 24 (see Figure 6k). ) and are added to the third and fourth AND circuits 29 and 30. Now that the transport vehicle 2 is traveling in the forward direction A and the first light receiving sensor 8 no longer detects the presence of the bar (LSB), the third AND circuit 29 outputs the second and seventh pulses. AND the outputs of the generation circuits 12 and 28, and add the pulse signal (see p in FIG. 6) to the eighth AND circuit 35.
The eighth AND circuit 35 is the flip-flop circuit 3
3 and the pulse signal of the third AND circuit 29 and apply that pulse signal to the S terminal of the flip-flop circuit 38, the output of the flip-flop circuit 38 becomes "1" in synchronization with the pulse signal. (See FIG. 6r), whereby a mark reading completion signal 39a can be obtained.

In addition, in this read completion signal generation circuit 39, when reading a new mark 3 is started, the OR circuit 37 applies the pulse signal j from the sixth pulse generation circuit 27 to the R terminal of the flip-flop circuit 38, so that the mark read completion signal is generated. The generation of the mark reading completion signal 39a is stopped, and also when the reset signal 37a from the outside is input, the generation of the mark reading completion signal is also stopped.

Furthermore, when the transport vehicle 2 travels in the direction opposite to direction A, that is, in the backward direction, the bar of mark 3 will be detected from the lowest digit to the highest digit, but in this case, the shift registers 20 and 21 Since the pulse signal RP from the second AND circuit 14 is received at the _S1 terminal, the read output of the second light receiving sensor 9 is shifted from the most significant digit _D7 to the least significant digit _D0 . As a result, parallel information "01001010" is output to the output terminals D ₇ to _{D 0} in the same manner as above.

At this time, in the reading completion signal generation circuit 39, since the first light receiving sensor 8 first started detecting a bar, the flip-flop circuit 33 receives a pulse signal from the fifth AND circuit 31, and its output becomes "1". ” becomes. When the reading of the mark 3 is completed, the second light receiving sensor 9 finally stops detecting the bar, so the fourth AND circuit 30 generates a pulse signal, thereby completing the mark reading in the same way as above. A signal 39a can be obtained.

In the device of this embodiment as described above, none of the first, second, and third light receiving sensors detect the presence of the bar, and the second and first light receiving sensors first detect the presence of the bar. When detection is starting, mark reading is completed when the first and second light-receiving sensors finally stop detecting the presence of the bar, so reading starts and ends. There is no need to separately provide a mark for indicating the mark reading completion signal, and the mark reading completion signal can be created by simply providing a simple logic circuit. Further, even if the carrier returns in the opposite direction during reading, a mark reading completion signal is not generated, and the completion of mark reading can always be accurately detected.

In the above two embodiments, a mark reading device for reading position information of an unmanned carrier was described, but the present invention is also applicable to a device for reading information such as the type and number of an article transported by a conveyor, vehicle, etc. In this case, a mark is affixed to the transported article and read by a fixed detector. In addition, the widths a ₁ and a ₂ of the bars, the distance b between them, and the distances d and e between the light receiving sensors satisfy the above-mentioned conditions e<a ₁ <d<a ₁
+b, e<b<d<a ₂ There may be variations as long as they are satisfied. Furthermore, as the detector and bar used for mark reading, a metal detector and a metal plate, or a magnetic sensor and a magnet may be used in addition to the above-mentioned light receiving sensor and reflecting plate.

As described above, according to the present invention, the first and second bars having different widths are arranged in the moving direction of the moving body, and the first, third, and second detectors are arranged on the moving body.
The type of bar is determined according to the output of the second detector when the first detector detects one end of the bar and the third detector detects the presence of the bar. and outputs the binary coded information of the mark as parallel information, and furthermore, all of the first, second, and third detectors no longer detect the presence of the bar, and the second and first detectors The mark reading completion signal is generated when the first and second detectors finally stop detecting the presence of the bar, so that mark reading can be easily performed with a simple configuration. This has the effect of accurately and easily detecting the completion of the process.

[Brief explanation of the drawing]

1 and 2 are a plan view and a side view of a mark reading device according to an embodiment of the present invention, FIGS. 3 and 4 are an enlarged side view of the main part of the device and a plan view of the mark, and FIG. 6 is a circuit configuration diagram of the above device, and FIG. 6 is a timing chart of the above device. 1... Road surface (detected object), 2... Unmanned carrier (moving object), 3... Mark, 4, 5... First bar, 4a,
5a...Starting end, 4b...Terminal end, 6...Second bar, 6a
... Starting end, 8, 9, 10... First, second, third light receiving sensor (first, second, third detector), 8a, 9
a, 10a...detection position, 23...reading circuit, 39...
Read completion signal generation circuit.

Claims (1)

[Claims] _1. A detected object to which a mark is attached, which is formed by arranging a plurality of first and second bars with widths a 1 and a 2 (a ₁ < _{a 2 )} with a mutual interval b, and the detected object. a moving body that moves relative to the body in the width direction of the bar, a first detector mounted on the moving body to detect one end of the bar in the width direction, and each detection position on the body to be detected is The distance d, e (e<a ₁ <d<a ₁ +b, e<b<d<
a ₂ ), the second and third detectors are respectively mounted on the moving body to detect the presence or absence of the bar, and the first detector detects one end of the bar in the width direction and detects the presence or absence of the bar. When the third detector detects the presence of a bar, the first detector detects whether the bar is detected by the first or second detector according to the detection signal of the second detector indicating the presence or absence of a bar. Mark 2 to determine whether it is a bar or not.
a reading circuit that outputs evolution information as parallel information;
The third detector receives the outputs of the first, second, and third detectors.
When none of the two detectors detects the presence of a bar and the second and first detectors begin to detect the bar, the first and second detectors detect the presence of the bar. A mark reading device comprising: a reading completion signal generation circuit that generates a mark reading completion signal only when the mark is no longer detected.