JPS6322268B2 - - 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 of moving objects that move along a fixed route, such as railway vehicles, various types of transportation, or industrial transport facilities, it is essential to periodically and continuously know the position of the moving object on the ground at all times. The most typical example is driving a linear motor car.

In order to operate a linear motor car smoothly, it is necessary to accurately know the position of the car body on the ground at all times within the distance between the motor poles arranged along the running route at regular intervals, and to adjust the field current accordingly. It is essential to rationally adjust the frequency, amplitude, phase, etc.

The principle of a typical position detection method that meets such demands will be explained with reference to FIGS. 1 and 2.

In Fig. 1, 1, 2, and 3 are conductors, each of which is bent into a waveform with a period of P, and each with a period of P/3.
The guided radio line 4 is formed by laying the wires on a flat surface while shifting the wires one by one. Therefore, the line 4 has a repeating structure with a period P, and when a high frequency current (50 to 200 kHz) is applied to the antenna 5 mounted on the mobile object,
Three-phase sinusoidal voltages are induced between the conductors 1, 2, and 3 as the moving body (antenna 5) travels.

If the z-axis is taken in the longitudinal direction of the line 4, the coordinate of the antenna 5 is z, and the voltages induced between conductors 1 and 2, 2 and 3, and 3 and 1 are respectively V ₁₂ , V ₂₃ , and V ₃₁ , then These can also be expressed by the following equation.

V ₁₂ = kcos (2π/P) z・e ^- 〓 ^zj 〓 ^z V ₂₃ = kcos (2π/P) {z+(P/3)}・e ^- 〓 ^zj 〓 ^z V ₃₁ = Kcos (2π/P) {z+(2P/3)}・e ^- 〓 ^zj 〓 ^z
...(1) α is the attenuation constant of the line 4, β is the phase constant of the line 4, and K is a constant determined by the shape and dimensions of the line 4 and the antenna 5, the separation distance between them, the magnitude of the excitation current, the frequency, etc. be.

Here, for the three voltages in equation (1), the positive sequence voltage V _P
and negative sequence voltage V _o are defined by the following equation.

V _P =V ₁₂ +e ^-j2 〓 ^/3 V ₂₃ +e ^j2 〓 ^/3 V ₃₁ V _o =V ₁₂ +e ^j2 〓 ^/3 V ₂₃ +e ^-j2 〓 ^/3 V ₃₁ ...(2) Expression (1) Substituting into equation (2) and rearranging, we get the following equation.

V _P = (3/2)ke ^j2 〓 ^z/p・e ^- 〓 ^zj 〓 ^z V _o = (3/2)ke ^-j2 〓 ^z/p・e ^- 〓 ^zj 〓 ^z ……(3) V _P Letting the phase difference between and _Vo be Φ, Φ=∠V _P −∠V _o =4πz/P (4). Note that ∠ is a symbol representing the argument of a complex quantity.

In other words, as shown in Figure 2, every time z increases by P/2, Φ also shows a linear increase of 2π,
By knowing the value of Φ, the position of the moving object (the position of the antenna 5) can be continuously known at a period of P/2.

Therefore, when applying the track 4 to automatic operation of a linear motor car, the period P must be twice the distance between the poles of the linear motor. For example, if the distance between the poles is 6 m, the period of the track 4 is P must be 12m.

However, it is extremely difficult to manufacture a guided radio line with such a long period. Also, the coupling distribution between antenna 5 and line 4 is expressed as (1)
To create a sinusoidal waveform as shown in the formula, the antenna 5
It is also necessary to increase the size in proportion to the period P of the track 4, making it difficult to attach it to the vehicle body.

The present invention has been made based on the above, and an object of the present invention is to provide a mobile body position detection method that can extend the measurement period without increasing the period P of the guided radio line.

In the position detection method (first invention) of the present invention, a guided wireless line formed by arranging two conductors so as to have a repeating structure with a predetermined period P is laid along a moving path, The moving object is equipped with two antennas spaced apart by P/4 in the longitudinal direction of the track, and a phase difference of π/2 is given between the antennas to generate a high-frequency current of frequency ₁ and multiply this by 2. A high-frequency current of frequency ₂ is applied, and the phase difference between the voltage related to frequency ₁ , which is induced between the conductors of the inductive radio line, multiplied by 2, and the voltage related to frequency ₂ , or the phase difference of the voltage related to frequency ₂ is determined. This system is characterized in that the position of the moving object is known by determining the phase difference between the voltage associated with frequency _{1 and the voltage associated with frequency 1} , which is doubled.

Further, in the second invention, N antennas are mounted on the moving body at intervals of P/N (N is 3 or an integer greater than 3) in the longitudinal direction of the track, and the antennas are spaced at intervals of 2π/N. A high-frequency current of frequency ₁ and a high-frequency current of frequency ₂ , which is doubled by giving a phase difference of N, were passed, thereby doubling the voltage related to frequency ₁ induced between the conductors of the guided radio line. The feature is that the position of a moving object can be determined by determining the phase difference between the object and the voltage related to frequency ₂ .

The guided radio line in the present invention may be a crossed guiding wire 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 as to maintain a positional relationship of 180 degrees Celsius. Examples include a spiral guide wire wound spirally at a predetermined period.

Hereinafter, one embodiment of the present invention will be described based on FIG. 3.

6a and 6b are conductors, and each conductor is bent into a waveform with a period of P, and the guided radio line 7 is formed by arranging the conductors so as to be shifted by P/2 from each other.

On the other hand, the moving body has a distance P/ in the longitudinal direction of the track 7.
An antenna 8a and an antenna 8b having the same size and the same shape except for the antenna 4 are mounted.

Here, a high-frequency current of frequency ₁ (angular frequency ω ₁ ) and a high-frequency current of frequency ₂ (angular frequency ω ₂ ), which is multiplied by 2, are simultaneously applied to the antennas 8a and 8b. Note that the phases of the currents of the antennas 8a and 8b were set to 0 and -π/2, respectively, and the amplitudes were set to be equal.

Line 7 by antenna 8a and antenna 8b
A voltage is induced between the conductors 6a and 6b of the line 7, this voltage is converted into an unbalanced voltage in the transformer 9 connected to the terminal of the line 7, and then divided into two voltages of frequency ₁ and frequency ₂ by the splitter 10. It is split into voltage.

The voltage V ₁ for frequency ₁ and the voltage V ₂ for frequency ₂ are respectively expressed as follows.

V ₁ = k ₁ [cos(2π/P)z・e ^- 〓 ^1z-j 〓 ^1z +e ^-j 〓 ^/2・cos(2π/P) {z+(P/4)} ・e ^- 〓 ¹ { ^{z+ (P/4)} } ^-j 〓 ¹ { ^z+(P/4) }]・e ^j( 〓 ^1t+ 〓 ¹⁾ ≒k ₁ e ^(j2 〓 ^z/P)- 〓 ^1z-j 〓 ^1z+j( 〓 ^1t+ 〓 ¹⁾ ……(5) V ₂ ≒k ₂ e ^(j2 〓 ^z/P)- 〓 ^2z-j 〓 ^2z+j( 〓 ^2t+ 〓 ²⁾ ……(6) φ is the phase value of the antenna current The other constants are the same as in equation (1). Also, subscript 1
is the quantity corresponding to frequency ₁ , and subscript 2 is the frequency
This means that the amount corresponds to ₂ .

These voltages V ₁ and V ₂ are amplified in amplifiers 11 ₁ and 11 ₂ , and voltage V ₁ is doubled in a multiplier 12 and then guided to a phase meter 13, where the voltage V ₂
is directly guided to the phase meter 13.

The phase difference Φ between the voltage V ₁ multiplied by 2 and the voltage V ₂ is expressed as follows.

Φ=2∠V ₁ −∠V ₂ = (2π/P)z−(2β ₁ −β ₂ )z + {(2ω ₁ −ω ₂ )t+(2φ ₁ −φ ₂ )} ……(7) By the way Since frequency ₂ is the frequency ₁ multiplied by 2, the phases of both voltages are completely synchronized, so the following relationship holds true.

ω ₂ =2ω ₁ →(2ω ₁ −ω ₂ )t=0 ……(8) φ ₂ =2φ ₁ →2φ ₁ −φ ₂ =0 ……(9) Also, in the frequency band of guided radio, the phase of the line The constant β can be approximated with sufficient accuracy as shown in the following equation.

β≒ω/(LC) ^1/2 (10) L and C are the inductance and capacitance per unit length of the line 7, respectively.

The following equation holds from equations (8) and (10).

β ₂ ≒2β ₁ → (2β ₁ −β ₂ )z≒0 (11) From the above relationship, the following equation can be obtained.

Φ=(2π/P)z...(12) That is, the position of z can be continuously known with a period of P through the measurement of Φ. This means that the measurement period is doubled compared to the conventional example described above.

Note that when the feeding phases to the antennas 8a and 8b are set to 0 and π/2, respectively, the following relationship holds true.

V ₁ ≒k ₁ e ^-j(2 〓 ^z/P)- 〓 ^1z-j 〓 ^1z+j( 〓 ^1t+ 〓 ¹⁾ V ₂ ≒k ₂ e ^-j(2 〓 ^z/P)- 〓 ^2z-j 〓 ^2z+j( 〓 ^2t+ 〓 ²⁾ ……(13) Therefore, a similar result can be obtained by using Φ′ defined by Φ′=∠V ₂ −2∠V ₁ ……(14) You can get results.

FIG. 4 shows an embodiment of the second invention.
=3 is illustrated.

The guided radio line 7 is similar to that shown in FIG. 3, and the antennas 8a, 8b, and 8c are arranged at intervals of P/3. In this case, antenna 8
Make the power supply amplitudes to a, 8b, and 8c equal, and set the phase to (1, e ^j2 〓 ^/3 , e ^-j2 〓 ^/3 ) or (1, e ^-j2 〓 ^/3 , e ^j2 〓
^/3 ), the same result as explained in the first invention can be obtained.

In other words, when the feeding phase to the antennas 8a, 8b, and 8c is (1, e ^j2 〓 ^/3 , e ^-j2 〓 ^/3 ), the line 7
The voltage V _{1 for frequency 1 and} the voltage V ₂ for frequency ₂ at the terminals of are respectively expressed as follows.

V ₁ = k ₁ [cos(2π/P)z・e ^- 〓 ^1z-j 〓 ^1z +e ^j2 〓 ^/3・cos(2π/P) {z+(P/3)} ・e ^- 〓 ¹ { ^{z+( P/3)} } ^-j 〓 ¹ { ^z+(P/3) } +e ^-j2 〓 ^/3・cos(2π/P) {z+(2P/3)} ・e ^- 〓 ¹ { ^z+(2P/3) } ^-j 〓 ^1(z+(2P/3) }]・e ^j( 〓 ^1t+ 〓
¹⁾ ≒(3/2)k ₁ e ^-(j2 〓 ^z/P)- 〓 ^1z-j 〓 ^1z+j( 〓 ^1t+ 〓 ¹⁾
……(15) V ₂ ≒ (3/2) k ₂ e ^-(j2 〓 ^z/P)- 〓 ^2z-j 〓 ^2z+j( 〓 ^2t+ 〓 ²⁾
...(16) A relationship similar to equation (13) is obtained, and the position can be determined in the same manner as described above.

Note that by using the three antennas 8a, 8b, and 8c, the 3rd, 9th, 15th... harmonics of the coupling distribution waveform between the antenna and the line cancel each other out, improving measurement accuracy. .

In the second invention, generally when using N (N≧3) antennas, the antenna spacing is P/N,
If the feeding phase difference between adjacent antennas is ±2π/N, the position can be determined as described above.

As explained above, according to the present invention, the position detection period of the moving body can be made equal to the period P of the track, and the detection period can be doubled compared to the conventional method. In other words, in order to obtain the same detection period, the period of the line needs to be half of that of the conventional method, making it easier to manufacture the line. Furthermore, since the on-vehicle antenna can also be made smaller, it has many advantages in terms of implementation.

[Brief explanation of drawings]

Figures 1 and 2 are explanatory diagrams of a position detection system using a conventional guided radio line, Figure 3 is an explanatory diagram of an embodiment of the first invention, and Figure 4 is an illustration of an embodiment of the second invention. It is an explanatory diagram. 1, 2, 3: Conductor, 4: Inductive radio line, 5: Mobile-mounted antenna, 6: Terminal, 7: Buffer amplifier,
8: Duplexer, 9: Phase shifter, 10: Adder, 11:
Multiplier, 12: Phase meter, 13: Adder.

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 a moving path, and the moving object has a Two antennas are mounted at an interval of P/4 in the direction, and there is a distance of π/4 between the antennas.
Applying a high frequency current of frequency ₁ and a high frequency current of frequency ₂ which is multiplied by 2 with a phase difference of 2,
As a result, the voltage related to frequency ₁ induced between the conductors of the guided radio line multiplied by 2 and the voltage related to frequency ₂
or find the phase difference with the voltage related to frequency ₂
A moving body position detection method characterized in that the position of a moving body is determined by determining the phase difference between a voltage related to frequency 1 multiplied by 2 and a voltage related to frequency ₁ . 2. A guided radio line consisting of two conductors arranged so as to have a repeating structure with a predetermined period P is laid along a moving vehicle running path, and the moving body has a P/N (P/N) in the longitudinal direction of the track. N antennas are mounted at intervals of 3 or an integer greater than 3), and a phase difference of 2π/N is given between the antennas to generate a high frequency current of frequency ₁ and a frequency that is doubled. The position of the moving object is determined by applying a high-frequency current of ₂ and calculating the phase difference between the voltage of frequency ₁ , which is induced between the conductors of the inductive radio line, multiplied by 2, and the voltage of frequency ₂ . A mobile object position detection method that is characterized by knowing the position of a moving object.