JPS6243143B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a guided radio position detection method for detecting the position of a moving object running on a track, such as a train or a traveling crane, using a guided radio track.

In container yards at wharves, where it is difficult to install multiple pairs of guided wireless lines for absolute position detection because they are buried in the road surface, a relative position detection method that counts the number of intersections between a pair of twisted-pair guided wireless lines is recommended. used.
That is, as shown in FIG. 1, a pair of twisted-pair guided radio lines 1 is laid in parallel to the track of a moving body, and a radio frequency power source 2 is connected to this line.
A pair of antennas 5 and 6 are attached to the moving body at a constant interval in the length direction of this line. In the antennas 5 and 6, a current is induced in a direction (phase) corresponding to the direction (phase) of the current flowing in the twisted pair line 1 by the action of magnetic flux illustrated by the dotted line in FIG. Since intersections 3, 4, . . . are formed at regular intervals on the line 1, the phase of the current flowing through the line 1 alternates at intervals equal to the intervals between the intersections, as illustrated by the arrows in FIG.

Now, if the phase relationship between the antennas 5 and 6 and the line 1 is as illustrated by the solid line in FIG. 1, the currents flowing through the antennas 5 and 6 will have opposite phases to each other. After that, as the mobile object moves, the antenna 5,
If the positional relationship between antenna 6 and line 1 changes to the state shown by the dashed-dotted line in FIG. 1, the currents flowing through antennas 5 and 6 will be in the same phase. In this way, the antenna 5,
The phase relationship of the currents in No. 6 is reversed each time the antenna, that is, the moving object passes one intersection. Therefore, by counting the number of phase inversions using a counter or the like, the number of intersections that the moving object has passed through can be determined, and the relative position of the moving object can be determined.

In the above example, the position of the moving object is determined only relatively, so absolute positions are assigned at key points.
An absolute position detection method is also used. A typical method for detecting absolute position is to lay a plurality of paired guide lines in parallel with different intersection intervals and radio frequencies, and to combine the phase relationships of the antenna currents detected for each guide line. This method detects the absolute position of a moving object. However, as mentioned above, this method requires multiple guide lines to be laid in parallel, and cannot be applied to places where the site area is narrow or where maintenance is impossible due to buried track.

Another method for absolute position detection is to install radiation sources of specific radio frequencies at key points along the guide line for relative position detection as shown in Figure 1, and to detect these specific frequencies. This is used to detect that the moving object is in a predetermined position. However, this method requires a radio frequency radiation source and a frequency discriminator, which are expensive and complicated to maintain, and has the disadvantage of increasing system cost, especially when the number of absolute positions to be set is large.

The present invention has been made in view of the above-mentioned conventional drawbacks, and its purpose is to provide an inexpensive and simple absolute position detection method that can be used even in places where it is difficult to install multiple pairs of guided radio lines. It is in. The details of the present invention will be explained below with reference to the drawings.

FIG. 2 is a diagram illustrating the position detection antenna according to an embodiment of the present invention in relation to the pair-type inductive radio line 1, in which 7 is a reference antenna, 8 is an auxiliary antenna, 9 is a comparative antenna, and 2 is a radio frequency source, and 3 and 4 are intersections. The reference antenna 7 and the comparison antenna 9 are mounted on a moving body (not shown) along the track 1 so as to maintain a distance of l. Railroad 1
The intersection interval is a constant value L or twice the value 2L, and the value of l is set within a range that satisfies the relationship L≦l<2L.

FIG. 3 is a block diagram of a detection circuit 10 which is mounted on a moving body together with the antennas 7, 8 and 9 of FIG. 2 and receives outputs from the three antennas. Input terminals 7', 8' and 9' of detection circuit 10 receive the outputs of antennas 7, 8 and 9 of FIG. 2, respectively. 13 is a phase comparison circuit that compares the signal phases on input terminals 7' and 8' and outputs logic "1" or "0" depending on whether the comparison result is in opposite phase or in phase. . Similarly, 14 is a phase comparison that compares the signal phases on input terminals 7' and 9' and outputs logic "1" or "0" depending on whether the comparison result is in opposite phase or in phase. It is a circuit.
These phase comparison circuits also serve as analog/digital conversion circuits that generate digital signals according to the comparison results of analog quantities.

15 is an AND gate to which the outputs of the phase comparison circuits 13 and 14 are input; 16 is a five-stage shift register to which the output of the AND gate 15 is input; and receives a shift pulse S from the phase comparison circuit 13. 17 is an AND gate that decodes the contents of the shift register 16.

As the mobile object moves, the antennas 7, 8 and 9
is placed in the position shown in FIG. Since the antennas 7 and 8 are located across the intersection 3, the currents induced in each are in opposite phase, and therefore the phase comparator circuit 13 in FIG. A shift pulse S is supplied to the shift register 16 at the same time as being supplied to the input terminal. Similarly, since the antennas 7 and 9 are located across the intersection 4, the positions of the currents induced in each are in opposite phases, and therefore the phase comparator circuit 14 of FIG. 3 outputs a logic "1". Since both of its inputs are "1", the AND gate 15 outputs "1" to the shift register 16. As a result, the shift register 16 newly reads "1".

On the other hand, if the distance between intersections 3 and 4 is 2L in FIG. Since there is no intersection between the antennas 7 and 9 and the currents of both antennas have the same phase, the phase comparison circuit 14 outputs a logic "0". Therefore, the AND gate 15 outputs "0" and the shift register 16 newly reads "0".

FIG. 4 shows an example of the arrangement of the intersections a, b, c, d, and e of the pair-type guided radio line 1 in FIG. It is a diagram. As the moving body moves, the antennas 7, 8, and 9 are assumed to move to the right on the combination pattern of long and short while keeping the distance between them constant as the moving body moves. The illustration is gradually shifted downward. When the antennas 7 and 8 are located across the intersection a, "1" is read into the shift register 16 of FIG. 3 as described above. Next, when antennas 7 and 8 are located across intersection 6, the currents flowing through antennas 7 and 9 are in phase, so phase comparison circuit 14 outputs "0", and shift register 16 in FIG. New “0”
Load. Similarly, when antennas 7 and 8 are located across intersections c, d, and e, "0" and "1" are stored in shift register 16 in FIG. 3, respectively.
and “1” are read.

In this way, each time the reference antenna 7 passes an intersection, the reference antenna 7 and the comparison antenna 9
"1" or "0" is read into the shift register 16 of FIG. 3 depending on whether an intersection exists between the two. In the example of FIG. 4, when antennas 7 and 8 are located across intersection e, shift register 1
Each stage of 6 (the right side in the figure is the shift direction) 1
"1", "1", "0", "0" and "1" are respectively read into 6-1, 16-2, . . . 16-5. Therefore, when antennas 7 and 8 are located across intersection e, that is, antenna 7 is located at intersection e.
, the AND gate 17 outputs the output terminal 1.
Outputs logic "1" to 8. This output signal is displayed or read by an appropriate means to display the absolute position where the moving object is present, that is, the intersection e.

Outside the absolute position detection section illustrated in FIG. ”, therefore the input of the shift register 16 is always “0”. On the other hand, the "1" output of the phase comparator circuit 13, which is generated every time the reference antenna 7 passes an intersection, is output from the output terminal 1.
9 and becomes a relative position detection signal.

In FIG. 3, the AND gate 15 is removed and the output terminal of the phase comparison circuit 14 is connected to the shift register 1.
6, and the output of the phase comparison circuit 13 is used as a drive signal for the phase comparison circuit 14, it is possible to perform exactly the same operation as described above. That is, only when the reference antenna 7 passes an intersection in FIGS. 2 and 4, the result of the phase comparison between the antennas 7 and 9 is input to the shift register 16 as a digital signal of "1" or "0".

Furthermore, when the arrangement of the reference antenna 7 and the auxiliary antenna 8 is switched in FIG. 2, the reference antenna 7 The phase comparison with the comparison antenna 9 can be performed when the antenna reaches just before the intersection.
In this case, depending on the presence or absence of the intersection 4, that is, depending on whether the current phases of the antennas 7 and 9 are in phase or in opposite phases, the comparison result is set to "1" or "0", respectively. Phase comparator circuit 14 in Figure 3
When the moving body reaches the intersection e in FIG. 4, the data stored in the shift register in FIG. 3 becomes "11001" and the AND gate 17 outputs "1" to the output terminal 18.

FIG. 5 is a block diagram of another example of the circuit shown in FIG. These are the same elements as those explained in FIG.

FIG. 6 is a diagram showing an example of the arrangement of intersections within the absolute position detection section of the paired guided radio line 1, and is used to explain the operation of the circuit shown in FIG. If the intersection interval in the relative position detection section outside the absolute position detection section is set to a value larger than the above-mentioned interval l between the antennas 7 and 8, the value read into the shift register 16 in FIG. 5 in this section is always It becomes “0”. Therefore, the contents of the shift register 16 remain (00000) until the reference antenna 7 passes the intersection a in FIG. After that, when the reference antenna 7 passes the intersection a, "1" is read into the first stage 16-1 of the shift register 16 by the same operation as already explained in FIGS. 2 to 4.
As a result, the output terminal 18- of the AND gate 17-1
A logic “1” is output to the signal “1”. In exactly the same way, the reference antenna 7 is placed at the intersections b, c, and d in FIG.
Each time it passes through the AND gate 17- in Figure 5,
2, 17-3, 17-4... output "1" to their respective output terminals 18-2, 18-3, 18-4.... This makes it possible to detect the absolute position of the moving object at all of the intersections a, b, c...i.

FIG. 7 is a diagram showing another example of the antenna illustrated in FIG. 2, where 20 is a reference antenna, 21 is an auxiliary antenna, 22 is a comparison antenna, 1 is a pair of guided radio lines, and 3 and 4 are intersections. It is. A in Figure 7
As shown in FIG. 1, the reference antenna 20 is arranged perpendicularly to the line 1, while the auxiliary antenna 21 and the comparison antenna 22 are arranged parallel to the line 1.

B in Fig. 7 shows that near any intersection,
The relative value a of the power level received by the reference antenna 20 and the relative value b of the power level received by the auxiliary antenna 21 and the comparison antenna 22 are illustrated. The vertically arranged reference antenna 20 receives maximum power at the intersection, and as it moves away from this point, the received power asymptotically approaches zero. On the other hand, the received power of the horizontally arranged auxiliary antenna 21 and comparison antenna 22 becomes almost zero at the intersection, and as the distance from the intersection approaches, the received power approaches a constant value. On the other hand, the phase relationship between the currents induced in the reference antenna 7 and the comparison antenna 9 depends on whether or not the intersection 4 exists between the antennas 7 and 9, as illustrated in C and D of FIG. The same phase becomes opposite phase.

The reference antenna 20, auxiliary antenna 21 and comparison antenna 22 described above are connected to input terminals 7', 8' and 9' of the circuit of FIG. 3, respectively. However, in the circuit shown in FIG. 3, the phase comparator circuit 13 is replaced with a level comparator circuit having an equivalent function. This level comparison circuit is a circuit that outputs a logic "1" when the level difference between input terminals 7' and 8' exceeds a predetermined value. In this way, each time the reference antenna 20 passes an intersection, the level comparison circuit outputs a logic "1" to one input terminal of the AND circuit 15, the shift pulse input terminal of the shift register 16, and the output terminal 19. do.
The operations of the other parts in FIG. 3 are exactly the same as those described above.

In FIG. 7, the distance between antennas 20 and 21 is set to a value equal to the minimum distance L between the tracks, and only when antenna 20 is near an intersection, antenna 20
A configuration may be adopted in which the levels of induced currents of 0 and 22 are compared. An example of the level comparison result in this configuration will be explained with reference to the case of FIG. However, antenna 9
is located at the intersection 4), the level of the antenna 9 is almost zero, and the comparison result is "1".

As is clear from the above explanation, there are generally two types of intersection spacing: a small value p1 and a large value p2. , p2＞l
All you have to do is satisfy the relationship. p1 of these
The condition >l/2 means that the number of intersections included between both antennas is always a constant value, that is, 1 (in the case of Figure 2)
or two (if the placement of antennas 7 and 8 in Figure 2 is swapped), and p1
≦l is a necessary condition for detecting that intersections are arranged at short intervals. Also p2＞
The condition l is necessary for detecting that intersections are arranged at long intervals. The above condition can also be rewritten as p1≦l<p2, l<2p1.

In addition, various modifications have been shown for the reference antenna 20, the auxiliary antenna 21, and the comparison circuit that compares the current phase or level of these. It is only necessary to use an appropriate detection means such as a comparator circuit for comparing the current phase or level of the antenna for use or activating its output.

As explained in detail above, the method of the present invention is configured to display the absolute position in the longitudinal direction of the line by a combination pattern of long and short intersection intervals of the guided radio line, and to decipher the pattern using a reference antenna, a comparison antenna, etc. Therefore, a simple and inexpensive position detection method can be realized without installing lines in parallel or using a special radio frequency source.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram of the conventional system, FIG. 2 is a diagram illustrating the relationship between the antenna and the line in an embodiment of the present invention, and FIG. 3 is a block diagram of a detection circuit in an embodiment of the present invention. FIG. 4 is a diagram showing the relationship between a line and an antenna in one embodiment of the present invention, FIG. 5 is a block diagram of a detection circuit in another embodiment of the present invention, and FIG. 6 is a diagram showing a line in another embodiment of the present invention. and FIG. 7 are diagrams of other embodiments of the antenna and line of the present invention. 1... Twisted pair type guided radio line, 2... Radio frequency power source, 3, 4... Intersection, 5, 6... Antenna, 7, 20... Reference antenna, 8, 21...
Auxiliary antenna, 9, 22... Comparison antenna, 1
0...detection circuit, 13,14...phase comparison circuit,
16...Shift register.

Claims (1)

[Claims] 1. In a position detection method for a guided radio including a moving body moving on a predetermined route and a twisted pair type guided radio line laid along the moving route of the moving body,
The guided radio line is formed at short intervals p1 or long intervals p2 in the section where absolute position detection is required, and has a plurality of intersections whose long and short combination pattern over a predetermined number of intervals corresponds to the absolute position in the longitudinal direction of the guided radio line. The mobile body is equipped with a fixed interval l (p1≦l<p2,
l<2p1) Compare the phase or level of the current induced in the reference antenna and comparison antenna, which are arranged so as to maintain the same condition, and set the logic to ``1'' or ``0'' depending on whether they match or do not match. a comparison means for outputting ", a means for accumulating the output of the comparison means and identifying the accumulated content, and a means for detecting that the reference antenna is located near an arbitrary intersection of the guided radio line and the comparison means or its output. An inductive radio position detection method characterized by comprising a detection means for activating.