JPS6246830B2 - - Google Patents

Description

[Detailed Description of the Invention] Cross-type guided radio lines 1 that intersect at regular intervals along a track on which a moving object runs, as shown in FIG.
, and transmits a high frequency signal from the ground transmitter 2. In contrast, when horizontal and vertical loop antennas 3 and 4 are installed on a moving object (not shown), each antenna 3 and 4 receives a high frequency signal. The reception level of the high frequency signal from the crossed guided radio line 1 is
The result is as shown in Figure A. Of these two received signals, for example, the received signal from the vertical loop antenna 4 is shifted by π/2 by a phase shifter 5, and is added to the received signal from the horizontal loop antenna 3 in an adder 6 to form a composite received signal. , this is input to the phase comparator 11 via the filter 7 and the saturation amplifier 9,
On the other hand, the received signal of the horizontal loop antenna 3 is passed through a filter 8 and a saturation amplifier 10 to a phase comparator 11.
, the phase difference will show a waveform as shown in FIG. 2B.

The basis for obtaining such a result is as follows. In Fig. 3, the length between each pitch of the guided radio lines that intersect at a constant pitch is 1/2, and a transmission signal of sin2π ₀ t is supplied from the transmitter 2. Antenna 3 and vertical antenna 4 exhibit reception characteristics equivalent to two sets of horizontal loop antennas fixed at an interval of 1/4, and if the distance from intersection C to horizontal antenna 3 is x, then The reception level of horizontal antenna 3 is
It is expressed as sin2π/lx, and the reception level of the vertical antenna 4 is expressed as sin2π/l(x-l/4)=cos2π/lx.

Therefore, the received signal of the horizontal antenna is K ₁ sin(2π/lx)・sin(2π ₀ t)...(1) The received signal of the vertical antenna is K ₂ cos(2π/lx)・sin(2π ₀ t) ...(2) However, K ₁ and K ₂ are coupling coefficients (constants).

If the coupling coefficient of each antenna is appropriately selected and set as K ₁ = K ₂ and the phase of the received signal of the vertical antenna is changed by π/2, the received signal expressed by equation (2) is K ₁ cos (2π/lx) sin (2π ₀ t+π/2) = −K ₁ cos(2π/lx). cos(2π ₀ t) ...(3).

Adding the signals expressed by equations (1) and (3) using adder 6 yields K ₁ sin (2π/lx). sin(2π ₀ t) −K ₁ cos(2π/lx). cos (2π ₀ t) = -K ₁ cos (2π ₀ t + 2π/lx), and the phase of the composite signal is 2π/lx, which is proportional to x, so the waveform as shown in Figure 2B changes depending on the change in x. Phase difference can be determined.

This phase difference is determined by the phase comparator 11, converted into a digital quantity by the AD converter 12, and the positional relationship between the intersection and the antenna is determined, thereby making it possible to detect the position of the moving body.

In the conventional device described above, as can be understood from Figure 1, it is necessary to match the characteristics of the two sets of filters and the saturation amplifier, and it is also necessary to match the characteristics against changes in the external environment such as temperature changes. However, it is necessary to select parts, and when adjustments and other adjustments are taken into consideration, the cost becomes high.

Therefore, in the present invention, without using such two sets of filters, saturation amplifiers, etc., one
This system uses a set of filters, saturation amplifiers, etc., and is configured so that the input from the horizontal loop antenna and vertical loop antenna is switched by an analog gate so that the input can be input to the filter, saturation amplifier, etc., thereby solving the above-mentioned drawbacks. It is.

One implementation of the present invention shown in FIG. 4 will be described below. In FIG. 4, the same reference numerals are used for the same parts as in FIG. 1.

Cross-type guided radio lines 1 are arranged along a track on which a moving object moves, intersecting at a constant pitch, and a transmitter 2 transmits a high-frequency signal to the crossed guided radio lines 1.

Although not shown, a reference point is specified on the moving body, and horizontal and vertical loop antennas 3 and 4 are fixed at positions determined with this reference point as the origin. Then, when the specific reference point of the moving body comes to the intersection of the guided radio line 1, the reception level of the vertical loop antenna 4 becomes the highest, and the specific reference point is
The horizontal loop antenna 3 is configured so that the reception level of the horizontal loop antenna 3 becomes the highest when the horizontal loop antenna 3 reaches the intersection of the horizontal loop antenna 3 and the antenna 3.

Reference numerals 13 and 14 are analog gates that receive inputs from the vertical loop antenna 4 and the horizontal loop antenna 3. Analog gates 13 and 14
The output sides of both are connected to a common filter 7, and the output sides thereof are connected to a saturation amplifier 9, and further connected via an A/D converter 12 to a microcomputer 15 that performs arithmetic processing to be described later. 16
is a signal line for analog gate switching, which sends a time-divided signal from the microcomputer 15 to the analog gates 13 and 14 to switch the antenna input.

With the above configuration, the signals received by the horizontal and vertical loop antennas 3 and 4 are switched by the analog gates 13 and 14, and the same filter 7
The signal passes through a saturation amplifier 9, and the reception level of each antenna is read out as a digital quantity in a time-division manner.

As shown in Fig. 2, the level of the signal received by the horizontal loop and vertical loop antennas 3 and 4 is a function of the distance x between the reference point on the moving object and the guided radio line intersection, and is a function of the antenna shape and the antenna. If the distance and position between the guided radio lines are selected appropriately, the level of the signal received by the vertical loop antenna 4 is V=K ₃ sinπ/Lx...(4), and the level of the signal received by the horizontal loop antenna 3 is can be obtained as H=K ₄ .cosπ/Lx (5).

Here, L is the intersection pitch of the guided radio line,
K ₃ and K ₄ represent constants. Further, when the values of V and H are negative, it indicates that the phase of each received signal is inverted, and can be expressed as minus (-).

Therefore, by using the microcomputer 15 to calculate tan ^-1 V/H (6) from the received levels of both antennas (4) and (5), x/l is obtained, and the guided radio line 1 Reference point position x on the moving body from the light difference part of
can be detected.

However, since a normal level detection circuit does not detect the phase information of the received signal, as shown in Figure 5A,
The absolute value of equations (4) and (5) is obtained as the reception level.

In this case, equation (6) becomes tan ^-1 |V|/|H|...(6)', and the output from equation (6)' for distance x is as shown in Figure 5B. , this can be corrected by means as shown below, and an output proportional to x can be obtained. In other words,
The phase of the received signal of each loop antenna at each position is as shown in Figure 5C for the horizontal loop antenna 3 and as shown in Figure 5D for the vertical loop antenna 4, so the phase between the signals received by both loop antennas is as follows. The phase difference becomes as shown in figure E. When the phase difference shown in figure E is π, if the sign of the corresponding part shown in figure 5B is reversed (negative), it becomes proportional to x shown in figure 5F. You can get the output.

This is a means for comparing the phases between the respective received signals of the horizontal loop antenna 3 and the vertical loop antenna 4, and after delaying the horizontal loop for a certain period of time (a positive multiple of the period) in the delay circuit 17, If a delay detection method that compares the phase with the received signal is used, a binary determination is made between 0 and π, and the above-mentioned inversion is performed. In this case, the receiving filter amplifier is 1
The configuration shown in FIG. 4 enables position detection.

As described above, according to the present invention, it is only necessary to have one set of filters and saturation amplifiers, which are difficult to miniaturize and are expensive, and there is no need to make the characteristics of the filters too strict. This has almost no effect on detection accuracy, and the device can be made smaller and less expensive.

The present invention can be applied to crane guidance wireless devices, unmanned trolleys, self-propelled robots, etc.

[Brief explanation of the drawing]

FIG. 1 shows an example of a conventional moving body position detection device. FIG. 2A shows the reception levels of the horizontal loop antenna and the vertical loop antenna in correspondence with the induction wire line of FIG. 1, and FIG. 2B shows the phase comparator output. FIG. 3 is a reference diagram for explaining position detection. FIG. 4 shows an embodiment of the present invention. FIGS. 5A, B, C, D, E and F are explanatory diagrams of position detection in the present invention. 1...Cross-type guided radio line, 2...Transmitter, 3
...Horizontal loop antenna, 4...Vertical loop antenna, 5...Phase shifter, 6...Adder, 7, 8...
Filter, 9, 10...Saturation amplifier, 11...
Phase comparator, 12...A/D converter, 13, 14
... Analog gate, 15 ... Microcomputer, 16 ... Time division signal line, 17 ... Delay detection circuit.

Claims (1)

[Claims] 1. In a position detection device that detects the position of a moving body using guided radio lines that intersect at a certain pitch, a specific reference point of the moving body is located on the moving body at the intersection of the guided radio lines. and an antenna that has the highest reception level when the reference point comes between the intersections of the guided radio lines, and switches the antenna reception signals connected to each of the two antennas. A level detection circuit consisting of a set of filters, amplifiers, A/D converters, etc. that detects the level of the analog gate and analog gate output signal and converts it into a digital signal, and a digital logic operation circuit such as a microcomputer. and detecting the received signal level from the guided radio line received by both antennas in a time-divided manner by the same level detection circuit,
Position detection characterized in that it is determined where the reference point of the moving body is located between the two intersections of the guided radio track by calculating the ratio of the two reception levels with a digital logic operation circuit. Device. 2. In the mobile object position detection device according to claim 1, the phase difference between the received signals from both antennas, which are switched by the analog gate, is determined as a binary value of 0 or π by a delay detection circuit, and the Determining whether the reference point is on the left or right of the center of adjacent intersections of guided radio lines, and compensating for the uncertainty that occurs only by comparing the levels of the position detection device according to claim 1. Characteristic position detection device.