JPS6246829B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a mobile body position detection method using guided radio.

In the automatic operation and operation management of various types of transportation such as railway vehicles or industrial transportation, it is often essential to continuously know the position of a moving object on the ground within a certain period of time. ,
The most typical example is the automatic operation of linear motor cars.

As a typical method that meets this demand, a position detection system using a three-conductor guided radio line has been proposed, and this will be explained with reference to FIGS. 1 and 2.

In FIG. 1, 1, 2, and 3 are conductors, and a guided radio line 4 is formed by these conductors. 5 is an antenna mounted on a mobile object.

Each of the conductors 1, 2, and 3 is bent into a waveform shape with a period P on a plane, and is arranged at intervals of P/3, so that the guided radio line 4 as a whole has a repeating structure with a period P.

Here, if the separation distance between the guided radio line 4 and the antenna 5 and the dimensions of the antenna 5 are appropriately selected and a high frequency current (50 to 200 KHz) is applied to the antenna 5, there will be no movement between the conductors 1, 2, and 3. As the body moves, a sinusoidal voltage is induced by electromagnetic induction.

Now, let the distance from the terminal of the guided radio line 4 to the antenna 5 be z, and the conductors 1 and 2, 2 and 3, and 3 and 1
The voltages induced between them are V12, V23,
Assuming V31, V12=k cos(2π/P)z V23=k cos(2π/P)(z+P/3) =k cos{(2π/P)z+2π/3} V31=k cos(2π/P) (z+2P/3) =k cos {(2π/P)z−2π/3}
...(1) It can be expressed as:

Here, k is a constant determined by the shapes and dimensions of the guided radio line 4 and the antenna 5, the distance between them, the magnitude of the current, and the frequency.

Now, the positive sequence voltage Vp and negative sequence voltage Vn for V12, V23, and V31 are defined as shown in the following equation.

Vp=V12+e=V23 +e〓V31 Vn=V12+e=V23 +e〓V31 …(2) From equations (1) and (2), Vp=(3/2)ke〓 Vn=(3/2)ke=…(3) is obtained.

Determining the phase difference φ between Vp and Vn, we get φ=∠Vp−∠Vn=4πz/P…(4) (∠: symbol that means a flat angle of a complex number).

This can be determined by placing a signal processing circuit at the terminal of the guided radio line 4 and performing analog calculations corresponding to equations (1) to (4) to obtain the phase difference φ=∠Vp−∠Vn. As shown in FIG. 2, this means that the moving body position z can be continuously known at a period of P/2.

However, in actual guided wireless lines, there are inevitably some manufacturing errors in the shape and dimensions of the conductor, which causes crosstalk voltage between the positive and negative phase voltages, causing position detection errors. Become.

The present invention solves the above-mentioned problems of the prior art, and aims to provide a moving book position detection system that is free from position detection errors due to crosstalk.

In the position detection method of the present invention, a guided radio line consisting of two conductors arranged so as to have a repeating structure with a predetermined period P is laid along the traveling path of the moving object, while the guided radio line is By arranging three antennas in a line at intervals of P/3 in the longitudinal direction of the radio line and exciting these antennas with signals of different frequencies, the radio waves induced between the conductors of the guided radio line are Selectively receive the voltage of It is characterized in that the position of the moving object is detected based on the phase difference between the phase voltage and a reference phase signal derived from a carrier wave power source.

Since the guided radio line in the present invention is composed of two conductors, it is not affected by crosstalk at all.
Such an inductive radio line is a cross-type inductive radio line in which two conductors are arranged on a plane so as to intersect with each other at predetermined intervals, or two conductors are arranged in such a way that they each maintain a 180° positional relationship. Examples include a spiral guided radio line formed by winding the wire in a spiral shape at a predetermined period.

Examples of the present invention will be described below.

FIG. 3 is an explanatory diagram of one embodiment of the present invention. 6
Reference numerals a and 6b are conductors, and each conductor is bent into a waveform with a period P, and is arranged to be shifted by P/2 from each other to form a guided radio line.

On the other hand, antennas 7a, 7b, and 7c are arranged in a line along the longitudinal direction of the guided radio line at a distance of P/3 [or an integral multiple of (P/3)+(P/2)] on the moving body. and each antenna 7a, 7b, 7
c is excited by high-frequency currents of different angular frequencies ωa, ωb, and ωc oscillated from the transmitters 8a, 8b, and 8c, respectively.

Conductors 6a, 6b from antennas 7a, 7b, 7c
The signal induced by
The signals are separated into signals of respective angular frequencies ωa, ωb, and ωc.

Letting the voltages of the signals of angular frequencies ωa, ωb, and ωc be Va, Vb, and Vc, respectively, these can be expressed as follows.

Va=ka cos(2π/P)z ・e ^-( 〓 ^a+j 〓 ^a)z+j 〓 ^at Vb=kb cos(2π/P)(z+P/3) ・e ^-( 〓 ^b+j 〓 ^{b )(z+} 〓 ^)+j 〓 ^bt ≒Kb cos {(2π/P)z+2π/3} ・e ^-( 〓 ^b+j 〓 ^b)z+j 〓 ^bt Vc=kc cos(2π/P) (z+P/ 3) ・e ^-( 〓 ^c+j 〓 ^c)(z+ 〓 ^)+j 〓 ^ct ≒Kc cos {(2π/P)z−2π/3} ・e ^-( 〓 ^c+j 〓 ^c)z+j 〓 ^ct …(5) In addition, ka, kb, Kc are constants, αa, αb, αc
and βa, βb, βc are the angular frequencies ω
These are the attenuation constant and phase constant of the guided radio line for the signals a, ωb, and ωc.

These voltages Va, Vb, Vc are applied to amplifiers 11a, 1
1b and 11c, and is amplified by square law detection circuits 12a,
12b and 12c, and the square value is determined as follows.

｜Va｜ ² = ka ² e ^-2 〓 ^az cos ² (2π/P)z = (1/2) ka ² e ^-2 〓 ^az・{1+cos(4π/P)z} ｜Vb｜ ² = kb ² e ^-2 〓 ^bz・cos ² {(2π/P)z+2π/3} = (1/2)kb ² e ^-2 〓 ^bz・[1+cos{(4π/P)z−2π/3}] |Vc| ² =kc ² e ^-2 〓 ^cz・cos ² {(2π/P)z−2π/3} =(1/2)kc ² e ⁻² 〓 ^cz・[1+cos{(4π/P)z+2π/3] } ...(6) By guiding the outputs from the square law detection circuits 12a, 12b, 12c to the subtraction circuits 13a, 13b, 13c, the difference between |Va| ² , |Vb| ² , |Vc| ² Proportional voltages Veu, Vev, and Vew are found.

In other words, Veu=k2(|Va| ² −|Vb| ² ) Vev=k2(|Va| ² −|Vb| ² ) Vew=k2(|Va| ² −|Vb| ² )...(7) is obtained. It will be done. Note that k2 is a constant.

The guided radio line length is relatively short, and ωa, ω
The values of b and ωc are close to each other, and each transmitter 8
If the outputs of a, 8b, and 8c are the same, approximate as Ka=kb=kc=kc=k1 e ^-2 〓 ^az = e ^-2 〓 ^bz = e ^-2 〓 ^cz = e ^-2 〓 ^z Can be done.

Therefore, the modulation circuits 14a, 14b, 14c
, the carrier wave e ^j 〓 ^t guided from the carrier frequency power supply 17 with voltages Veu, Vev, and Vew is 100%.
The voltage obtained by modulating each
Vu, Vv, and Vw are expressed as follows.

Vu=(√3/2)k1 ² k2cos {(4π/P) z+π/6}・e ^j 〓 ^t Vv=(√3/2)k1 ² k2cos {(4π/P)z +(π/6) −2π/3}・e ^j 〓 ^t Vw=(√3/2)k1 ² k2cos {(4π/P) z+(π/6)+2π/3}・e ^j 〓 ^t …(8) Next, modulation The voltage Vu from the circuit 14a is directly led to the adder circuit 16, and is then connected to the modulation circuits 14b and 14c.
The voltages Vv and Vw from 1 are given phase shifts of +120° and -120° by phase shift circuits 15b and 15c, respectively, and then led to an adding circuit 16 to obtain the following negative phase voltage Vn.

Vn=Vu+e〓Vv +e〓Vw = (3√3/4) k1 ² k2e ^j { ⁽ 〓 ^)z+ 〓} ・e ^j 〓 ^t …(9) Here, the carrier wave e guided from the carrier wave power source 17
^j 〓 Calculating the phase difference ∠Vn between ^t and the negative phase voltage Vn, we get ∠Vn = (4π/P)z + π/6 ...(10), and every time z increases by P/2, the value of ∠Vn also decreases by 2.
π increases, and ∠ in the phase meter 18
Through the measurement of Vn, the position z of the moving object can be detected periodically and continuously.

In addition, the positive sequence voltage Vp is Vp=Vn+e〓Vv +e ^j2 〓 ³ Vv = (3√3/4) k1 ² k2e ^-j { ⁽ 〓 ^)z+ 〓} ・e ^j 〓 ^t …(11) From this, −∠Vp=(4π/P)z+π/6 (12) can be obtained, and the same result as above can be obtained.

Above, the guided radio line length is relatively short and ω
We have explained the case where the values of a, ωb, ωc are close to each other, but when the length of the guided radio line becomes long or when the frequency interval of ωa, ωb, ωc) is large, e ^-2 〓 ^az , e− ² 〓 ^bz ,
The deviation of e ^-2 〓 ^cz becomes large, and the method of the above embodiment causes a measurement error.

In order to maintain measurement accuracy, it is necessary to know the approximate value of z on the ground and to compensate for the effects of line attenuation for each frequency.

Note that if there is a deviation between the values of ka, kb, and kc, this deviation is unrelated to z, so a fixed compensation method is used.

FIG. 4 is an explanatory diagram of one embodiment of a position sensing method incorporating compensation for line attenuation.

The mobile body includes antennas 7a, 8b, 7c and transmitters 8a, 8b, 8c described in the embodiment of FIG.
In addition, pilot signal antennas 7p1 and 7p
2,7p3 and a pilot signal transmitter 8p are mounted.

The transmitter 8p outputs a pilot signal with an angular frequency ωp, and its output is strictly controlled to maintain a constant value.

The antennas 7p1, 7p2, and 7p3 are arranged in a line in the longitudinal direction of the guided radio line with an interval of P/3.

The output of the transmitter 8p is divided into three equal parts, one of which is directly supplied to the antenna 7p1, and the other two are supplied to -120 by phase shift circuits 19b and 19c, respectively.
After receiving a phase change of ゜, +120゜, the antenna 7p
I am led to 2,7p3.

Therefore, an electromotive force (pilot signal) of a constant magnitude is induced in the guided radio line regardless of z. The pilot signal is guided to an AGC signal generator 20 via a transformer 9 and a duplexer 10 provided at the ground station.

The AGC signal generator 20 measures the level Vp of the pilot signal to obtain an approximate value of the position of the moving object, and sends an appropriate AGC signal to the AGC amplifier 1 to compensate for the influence of line attenuation 2αaz, 2αbz, 2αcz, respectively.
1a, 11b, and 11c, and maintain the relationship e ^-2 〓 ^az = e ^-2 〓 ^bz = e ^-2 〓 ^cz for the signals of each frequency to ensure the accuracy of position measurement. In this way, the AGC amplifiers 11a, 11b, 11
Voltages Va, Vb, Vc for each angular frequency ωa, ωb, ωc compensated for the influence of line attenuation in c
will be subjected to signal processing in the same manner as in the previous embodiment.

Also, due to changes in ambient temperature, αa, αb, αc
The same problem as above occurs when the value of z changes, but the result is equivalent to a slight change in z, and it is possible to deal with it in the same way as above.

Note that the number of pilot signal antennas, the spacing, and the feeding phase difference are not limited to three, P/3, and ±120° combinations, but two,
P/4 [or an integer multiple of (P/4) + (P/2)], which may be ±90°, and generally N, P/4
This is a combination of n and ±2π/N.

The conductor arrangement of the guided radio line used in the present invention is not limited to one in which both conductors are shifted by P/2, but one conductor is shifted by P/3 with respect to the other conductor. It may be hot.
With such a conductor arrangement, spatial harmonic components of integral multiples of 3, such as the 3rd, 9th, 15th, etc., do not appear in the induced voltage between the conductors, which is advantageous in determining the dimensions and shape of the antenna. becomes.

As explained above, the present invention detects the position of a moving object using a guided radio line consisting of two conductors, and eliminates the possibility of position detection errors caused by crosstalk. This simplifies the structure of the system, making it easier to apply it to large-scale, long-distance mobile vehicle operation systems.

[Brief explanation of the drawing]

1 and 2 are explanatory diagrams of a moving object position detection system using a three-conductor method, FIG. 3 is an explanatory diagram of one embodiment of the present invention, and FIG. 4 is an explanatory diagram of another embodiment of the present invention. , is an explanatory diagram of a system with an added function of compensating for the influence of line attenuation. 6a, 6b... Conductor, 7a, 7b, 7c... Antenna, 8a, 8b, 8c... Transmitter, 9... Transformer, 10... Duplexer, 12a, 12b, 12c
...square law detection circuit, 13a, 13b, 13c...
Subtraction circuit, 14a, 14b, 14c... Modulation circuit, 15b, 15c... Phase shift circuit, 16... Addition circuit, 17... Carrier wave power supply, 18... Phase meter.

Claims (1)

[Claims] 1. A guided radio line consisting of two conductors arranged so as to have a repeating structure with a predetermined period P is laid along the traveling path of a moving object, and on the other hand, a guided radio line with P in the longitudinal direction of the guided radio line is installed on the moving object. By arranging three antennas in a line with an interval of /3 and exciting each antenna with a signal of a different frequency, the voltage induced between the conductors of the inductive radio line can be reduced to The terminal selectively receives the voltage, calculates the square value of the envelope for the voltage of each frequency, modulates a new carrier wave with a voltage proportional to the difference between these square values, and corrects the voltage obtained by this. A moving body position detection method that detects the position of a moving body based on the phase difference between the normal phase or negative phase voltage and a reference phase signal derived from a carrier wave power source.