JPS5855461B2 - How to detect the position of a moving object - Google Patents

Abstract

PURPOSE:To ensure economical, high-accuracy position detection by using 3-phase 3-conductor induction wireless channel and utilizing the positive and negative phase voltages of receipt signal thereof. CONSTITUTION:The 3-phase 3-conductor induction wireless channel formed by spirally winding, while shifting at 1/3 pitch, conductors 1-3 round a polar surface 5 at one fixed pitch is laid along the travel course of an antenna 6, i.e. transfer body. The information of the position of the antenna 6, i.e. transfer body, can be obtained in terms of the change of the difference of the positive and negative phases of the signal received from the antenna 6 by the induction wireless channel 4.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for detecting the position of a moving body using guided radio.

2. Description of the Related Art Detecting the position of a moving object using a guided radio line laid along the route of the moving object has been conventionally performed.

For example, as shown in FIG. 5, there is a known position detection method using a guided radio line in which four conductors 51, 52, 53, and 54 are spirally wound at the same and constant pitch around the outer periphery of a columnar surface 55. There is.

In this case, a pair of opposing conductors 51. Generally, the conductor 52 is used as an outgoing path, and the conductors 53 and 54 are used as a return path.

However, it is said that it is extremely difficult to manufacture such guided radio lines with high precision, and deterioration in manufacturing precision increases crosstalk between lines and deteriorates position detection accuracy.

That is, if there is a small geometrical error in the arrangement of the conductors 51, 52, 53, 54, the conductors 51, 52, 53, .
The Shigenobu line formed by 54 constitutes the third line and 2
This causes crosstalk, which deteriorates position detection accuracy.

Further, a position detection method is also known that utilizes a guided radio line consisting of multiple sets of intersecting pairs of wires with intersections provided at predetermined intervals.

This method necessarily requires a large number of lines (pairs),
As the cost of guided radio lines increases, the influence of inter-line crosstalk on measurement accuracy cannot be ignored.

The present invention solves the problems of the prior art described above.
The object of the present invention is to provide a method for detecting the position of a moving body that is economical and has excellent detection accuracy.

That is, the present invention provides an induction system in which three conductors having a repeating period P are arranged at intervals of P/3 so that a sinusoidal inter-conductor voltage is induced between each conductor as the position of a moving body changes. A radio line is laid along the travel path of the mobile object, and when this guided radio line is excited by the antenna mounted on the mobile object, a voltage V1 is induced between each of the three conductors.
2. When the positive sequence voltage Vp and negative sequence voltage Vn for V23 and VB2 are defined as in the following formula, the above positive sequence voltage V
This method is characterized in that the position of the moving body is detected by determining the phase difference between the phase difference voltage Vn and the negative phase voltage Vn.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

Figure 1 shows -f of the guided radio line used in the present invention.
11 is shown.

1, 2, 3 are conductors, 4 is a columnar surface, and each conductor 1, 2,
3 is shifted by P/3 and wound spirally around the outer periphery of the columnar surface 4 with a period P, thereby forming the guided radio line 5.

Further, 6 is an antenna mounted on a mobile object.

Here, by appropriately selecting the separation distance between the line 5 and the antenna 6 and the dimensions of the antenna 60, a voltage is induced between each conductor 1, 2, and 3 by the magnetic field formed by the antenna 6. The voltage takes on a sinusoidal shape as the position of the moving body changes.

Assuming that the voltages induced between conductors 1, 2.2, 3.3, and 1 and reaching the receiving end are V12, V23, and VB2, respectively, these can be expressed as in the following equations.

V12=k cos 2πz/P V23=kcos ((2πz/P)+2π/3)V
31=k cos ((2πz/P) 2π/3
)・・・・・・・・・(1) Z: Position of the antenna 6 along the track 5.

k: Constant determined by the structure of the line 5.

Now, for each voltage in equation (1), the positive-sequence voltage vp, negative-sequence voltage Vn, and zero-sequence voltage Vo are defined by the following equations.

Substituting equation (1) into equation (2) and rearranging it gives the following equation.

Vp=(3/2)kej2"Z/P Vn=(3/2)ke j2πz/P ・・・・・・・・・A3) V.

Letting Φ be the phase difference between Vp and Vn, the following equation is obtained.

Φ−Vp −ZVn = 4 πz /P ・
...(4) L: Symbol meaning declination angle.

That is, as shown in Fig. 2, Φ shows a linear increase of 2π every time it increases by zlJ''-P/2, and through the measurement of Φ, the moving body position 2 can be changed to P/2. Can be measured continuously in cycles.

On the other hand, when the line 5 and the antenna 6 are brought close to each other in order to reduce the coupling loss between them, or when the antenna has dimensional restrictions, spatial harmonic components are generated and waveform distortion occurs, which can cause position detection. This will cause errors.

That is, each conductor 1. The voltages V12, V23, and V31 between the three voltages are expressed as including odd-numbered spatial harmonic components as shown in the following equation.

m=o, 1.2.3,... C: Fourier coefficient.

2m+1 In this case, when each voltage in equation (5) is subjected to signal processing to obtain the positive phase voltage Vp and negative phase voltage Vn in equation (3), the following equation is obtained.

In other words, by performing the signal processing of equations (2) and 3), the 3.9th, . (which is expected to be third-order harmonic reduction) disappears, and the cause of position detection error can be eliminated.

FIG. 3 shows an example of a processing circuit for signals induced between the conductors 1, 2, and 3.

71.7-2.7-3 is a buffer amplifier, 82a, 83
b is a 11200 phase shifter, 8-2b.

8-3a is a +120° phase shifter, 91 and 9-2 are adders,
10 is a phase meter.

The adder performs signal processing to obtain Vp and Vn in equation (3), and then the phase meter performs processing in equation (4), and based on this, the position of the moving object can be determined.

FIG. 4 shows another embodiment of the guided radio line used in the present invention, in which conductors 41°, 42, 43 are wired on an insulating substrate 44 having a large number of protrusions 45 on both edges. It is constructed in a flat shape.

In the case of a round shape as shown in Figure 1, the line structure is not completely symmetrical in terms of relative position to the antenna, so some even-order harmonic components will be included. This ensures symmetry, eliminates the generation of even-order harmonic components, and further improves position detection accuracy.

The effects of the present invention described above are as follows.

(1) Since only three conductors are required to constitute the guided radio line, the structure is simplified and manufacturing is facilitated.

(2) When the guided radio line and the antenna are brought close together, spatial harmonic components will be generated in the voltage between the conductors, but in the present invention, harmonic components of multiples of 3 are generated in the signal processing process. This enables highly accurate position detection.

(3) In the 4-conductor system, the heavy trust line constitutes the 3rd line, and the position detection accuracy may deteriorate due to inter-line crosstalk, whereas in the 3-conductor system as in the present invention, the 3rd line is a zero-phase line. Since this is a return line to the ground, it has a high loss, so the effects of secondary crosstalk can be ignored.
Highly accurate position detection becomes possible.

[Brief explanation of drawings]

Fig. 1 is an explanatory diagram of one embodiment of the guided radio line used in the present invention, Fig. 2 is an explanatory diagram of the relationship between the moving object position and the phase difference, and Fig. 3 is the signal processing used in the present invention. FIG. 4 is an explanatory diagram of one embodiment of the circuit, FIG. 4 is an explanatory diagram of another embodiment of the guided radio line used in the present invention, and FIG. 5 is an explanatory diagram of a conventional example of the guided radio line.

Claims (1)

[Scope of Claims] 1. Having a repetition period P such that a sinusoidal inter-conductor voltage is induced between each conductor as the position of the moving body changes 3.
A guided radio line consisting of book conductors shifted by P/3 is laid along the route of the moving object, and by exciting this guided radio line with the antenna mounted on the moving object tower, the three above-mentioned Voltages induced between each conductor V12, V23, V
When the positive-sequence voltage Vp and negative-sequence voltage Vn for B2 are defined as in the following equations, the position of the moving body is detected by determining the phase difference between the positive-sequence voltage Vp and the negative-sequence voltage Vn. A method for detecting the position of a moving object.