JPH0235267B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] The present invention relates to a system for continuously detecting the position of a moving object using guided radio.

[Background of the Invention] For example, in the automatic operation of a linear motor car, the position of the car body is constantly detected on the ground within the distance between motor poles (propulsion coils) placed at regular intervals along the running route. , it is considered essential for the smooth operation of this vehicle to rationally adjust the frequency, amplitude, and phase of the field current accordingly.

The most typical method among those currently proposed as means to meet this demand will be explained with reference to FIGS. 1 and 2.

In Figure 1, 1, 2, and 3 are conductors, respectively.
4 is an inductive radio line formed by conductors 1, 2, and 3, and 5 is a mobile tower-mounted antenna.

Each of the conductors 1, 2, and 3 is bent into a waveform shape on a plane with a period P (twice the distance between the motor poles), and is laid staggered by P/3, so the line 4 as a whole has a period P. It has a repeating structure. A frame-shaped loop coil is used as the antenna 5, and when this is excited with a high frequency current of 50 to 200 KHz, the magnetic field formed by the antenna 5 interlinks with the line 4 and is distributed between each conductor 1, 2, and 3. A voltage is induced.

If the distance from the starting point of the track 4 to the antenna 5 (vehicle body) is z, the dimensions of the antenna 5, the antenna 5
By appropriately selecting the separation distance between the conductors 1, 2, and 3, the induced voltage between each conductor 1, 2, and 3 can be made sinusoidal in z.

Now, the voltages between conductors 1 and 2, 2 and 3, and 3 and 1 at the terminals of line 4 are V12 (z) and V23, respectively.
(z), V31(z), then V12(z)=kcos2πz/P・e ^- 〓 ^z V23(z)=kcos2π(z+P/3)/P・e ^- 〓 ^z V31(z)=kcos2π( z+2P/3)/P・e ^- 〓 ^z
It can be expressed as ……(1).

Here, k: constant, γ: line propagation constant, γ=
α+jβ (α: attenuation constant of the line, β: phase constant of the line).

Here, it is assumed that the following signal processing is performed on V12 (z), V23 (z), and V31 (z) to obtain a positive sequence voltage Vp (z) and a negative sequence voltage Vn (z).

Vp (z) = V12 (z) + e ^-j2 〓 ^/3 V23 (z) +e ^j2 〓 ^/3 V31 (z) Vn (z) = V12 (z) +e ^j2 〓 ^/3 V23 (z) + e ^-j2 〓 ^/3 V31(z) ......(2) Substituting equation (1) into equation (2) and rearranging, Vp(z) = (3/2)ke ^(-j2 〓 ^z/p)- 〓 ^z Vn (z) = (3/2) ke ^(j2 〓 ^z/p)- 〓 ^z ………(3) If the phase difference between Vp (z) and Vn (z) is Φ, then Φ = ∠Vp ( z)−∠Vn(z)=4πz/p (4) Here, ∠: is a symbol meaning an argument.

That is, Φ is z as shown in Fig. 2.
Each time it increases, it shows a linear increase of 2π, and by measuring Φ, the antenna (vehicle body) position can be measured continuously at a period of P/2.

Also, V12(z), V23(z), V31 as follows:
Detection can also be performed using only the absolute value of (z). If we linearly detect the induced voltage between each conductor at the starting end of the line, find the absolute value of its envelope, and find its square value, we get |V12(z)| ² = k ² cos ² 2πz/P = k ² (1 + cos4π
z/P) |V23(z)| ² = k ² [1+cos4π(z+P/3)/
P]=k ² [1+cos {(4πz/P)−2π/3}] |V31(z)| ² =k ² [1+cos4π(z+2P/3)/
P]=k ² [1+cos {(4πz/P)+2π/3}]...
(5) Now, the carrier wave of angular frequency ωo is modulated by each value of equation (5), and these values are expressed as Vu (z) and Vv, respectively.
(z) and Vw(z), then Vu(z)=k ² (1+cos4πz/P)・e ^j 〓 ^ot Vv(z)=k ² [1+cos{(4πz/P)−2π/3}]・
e ^j 〓 ^ot Vw (z) = k ² [1 + cos {(4πz/P) + 2π/3}]・
e ^j 〓 ^ot ………(6).

Now, signal processing is applied to each voltage in equation (6) to obtain a positive sequence voltage Vp'(z) and a negative sequence voltage Vn'(z).

Vp′ (z) = Vu (z) + e ^-j2 〓 ^/3 Vv (z) +e ^j2 〓 ^/3 Vw (z) Vn′ (z) = Vu (z) + e _j2 〓 _/3 Vv (z) +e ^{- j2} 〓 ^/3 Vw (z) ......(7) The following equation is obtained from equations (6) and (7).

Vp′(z)=(2/3)k ² e ^(-j4 〓 ^z/P)+j 〓 ^ot Vn′(z)=(2/3)k ² e ^(j4 〓 ^z/P)+j 〓 ^ot ......(8) By comparing the phases of Vp'(z), Vn'(z) and the reference signal derived from the carrier wave power source, the following equation is obtained.

Φ′=∠Vn′(z)−∠e ^j 〓 ^ot =−(∠Vp′(z)−∠e ^j 〓 ^ot )=4πz/P……(9
) That is, exactly the same result as in equation (4) is obtained, and the vehicle body position can be measured continuously at a period of P/2.

The relationship in equation (9) can be obtained not only by the analog method as described above, but also by the digital method as follows.

Directly from equations (5), (6), and (7), Vp′ = [{|V12(z)| ² − (1/2) | V23(z) | ² −
(1/2) | V31 (z) | ² } −j (√3/2)・{ | V23 (z) | − | V31 (z) | ² }
]・e ^j 〓 ^ot Vn′=[{｜V12(z)｜ ² −(1/2)｜V23(z)｜ ² −
(1/2) | V31 (z) | ² } +j (√3/2)・{ | V23 (z) | ² − | V31 (z) | ²
}]・e ^j 〓 ^ot ......(10) The following equation is obtained from equations (9) and (10).

(4π/P)z=∠Vn′(z)−∠e ^j 〓 ^ot =tan ^-1 [(√
3/2) {|V23(z)| ² −|V31(z)| ² }/{|V12(z)|−(1/2)(|
V23(z)｜ ² +｜V31(z)｜ ² )}]……(11) In other words, |V12(z)|, |V23(z) obtained by linear detection of the voltage between adjacent conductors ) |, |
By converting V31(z) into a digital quantity using an AD converter and digitally processing this using a computer based on equation (11), the moving body position z can be calculated.
can be known.

However, the above method has the following drawbacks.

In other words, the period P of each conductor 1, 2, and 3 must be equal to twice the distance between the poles of a linear motor car, but in a practical linear motor car, the distance between the motor poles is expected to be approximately 6 m. Therefore, the conductor period P must be approximately 12 m.

Therefore, manufacturing the line 4 may be difficult and expensive.

In addition, in order to realize this method, it is necessary that the induced voltage between each conductor has a pure sine-broken shape with respect to z, as shown in equation (1), and therefore the length L of the antenna 5 is It becomes extremely large, P/7 to P/5 (1.7 to 2.4 m when P=12 m). When attaching an antenna to a car body, it is necessary to provide a notch in the car body to avoid the effects of eddy currents flowing through the car body, but it is not desirable from the viewpoint of the mechanical strength of the car body that this becomes large.

[Object of the invention] The present invention can make the position detection period of a moving object equal to the conductor period P of the track, and when this is applied to automatic operation of a linear motor car, the conductor period P can be made equal to the distance between motor poles. It is an object of the present invention to provide a moving body position detection method that can be used in the same manner as described above, that can reduce the size of the on-board antenna, and that can also facilitate the manufacture of railway tracks.

[Summary of the Invention] The main point of the present invention is to
has a periodic structure, and each conductor has a periodic structure of P/
An inductive radio line has been laid, consisting of three conductors arranged at three-point intervals and a straight conductor parallel to these three conductors, and this inductive radio line is excited by a mobile tower-mounted antenna. According to 3 above
The three voltages induced between each conductor of the book and the straight conductor are linearly detected and their envelopes (respectively |V10(z)|, |V20(z)|, |V30(z)| ) and convert these quantities into digital quantities, z=(P/2π) tan ^-1 [(√3/2) {−|V20(z)|+
|V30(z)|｝/{|V10(z)|-(1/2)(|V20(z)|+|V30(z)|)}] The position of the moving object can be determined by calculating The purpose is to continuously detect at a period P.

The principle of the present invention will be explained based on FIG.

In Fig. 3, 11, 12, 13, and 14 are conductors, respectively, and the conductors 11, 12, and 13 are bent into a waveform shape with a period P (twice the distance between motor poles), and each is bent by P/3. The conductor 14 is arranged in a straight line in parallel with the conductors 11, 12, and 13, thereby forming a guided radio line 15.

16 is a mobile antenna, 17, 18, 1
9 and 20 are terminating resistors for matching the characteristic impedance of each line.

By exciting the antenna 5 with a high frequency current, a voltage is induced between each conductor 11, 12, 13, and 14. Conductor 11 at the starting end of line 15
^Assuming that the voltages appearing ^between V20(z)=k1[+k2cos2 π(z+P/3)/P]
e〓 ^z V30(z)=k1[1+k2cos2 π(z+2P/3)/
P]e ^- 〓 ^z ……(12) Here, k1, k2: constants.

It is clear from Figure 3 that K1>k2,
The value in parentheses or [ ] on the right side of equation (10) is always positive for any value of z.

Now, if the above voltage is directly detected at the starting end of the line 15 and its envelope is determined, the following equation is obtained.

|V10(z)|=k1(1+k2cos2 πz/P)e ^- 〓 ^z |V20(z)|=k1[1+k2cos2 π(z+P/
3)/P]・e ^- 〓 ^z |V30(z)|=k1[1+k2cos2 π(z+2P/
3)/P]・e ^- 〓 ^z ......(13) Here, the new carrier wave of angular frequency ωo is modulated with each voltage in equation (11), and each is expressed as Vu''(z),
Assuming Vv″(z) and Vw″(z), the following equation is obtained.

Vu″(z)=｜V10(z)｜e ^j 〓 ^ot =k1(1+k2c
os2 πz／P)・e ^- 〓 ^z+j 〓 ^ot Vv″(z)=｜V20(z)｜e ^j 〓 ^ot =k1[1+k2c
os2 π(z+P/3)/P]・e ^- 〓 ^z+j 〓 ^ot Vw″(z)=｜V30(z)｜e ^j 〓 ^ot =k1[1+k2c
os2 π(z+2P/3)/P]・e ^- 〓 ^z+j 〓 ^ot ………(14
) The following signal processing is applied to these voltages to obtain the positive sequence voltage.
Vp″(z) and negative sequence voltage Vn″(z) are derived.

Vp″(z)=Vu″(z)+e ^-j2 〓 ^/3 Vv″(z
)＋e ^j2 〓 ^/3 Vw″(z) Vn″(z)＝Vu″(z)＋e ^j2 〓 ^/3 Vv″(z
)+e ^-j2 〓 ^/3 Vw″(z)……(15) The following equation can be obtained immediately from equations (14) and (15).

Vp″(z)=(3/2)k1・k2・e ^- 〓 ^z+(j2 〓 ^z
/P)+j 〓 ^ot Vn″(z)=(3/2)k1・k2・e ^- 〓 ^z-(j2 〓 ^z
/P)+j 〓 ^ot ......(16) By comparing Vp'' (z) or Vn'' (z) with the reference phase signal derived from the carrier wave power source, Φ'' of the following equation can be obtained.

Φ″＝∠Vp″(z)−∠e ^j 〓 ^ot =−(∠Vn″(z
)−∠e ^j 〓 ^ot =2πz/P (17) That is, through the measurement of Φ″, the moving body position z can be continuously known at a period of P.

Further, Φ'' can be determined by the following digital method.

The following equation is immediately obtained from equations (14) to (17).

(2π/P)z=Φ″=tan ^-1 [(√3/2){−|V20(z
)｜＋｜V30(z)｜}/{｜V10(z)｜ −(1/2)(｜V20(z)｜+｜V30(z)｜)}]...
...(18) That is, by envelope detection of V10(z), V20(z), and V30(z), |V10(z)|, |V20
(z) |, |V30(z)|, convert these quantities into digital quantities using an AD converter, digitally process the calculation on the right side of equation (18) to find Φ″, and from this Therefore, the moving body position z can be continuously known at a period of P.

Although the present invention is applicable to detecting the position of various moving bodies, it can be particularly suitably applied to automatic operation of linear motor cars.

In this case, the guided radio line can be formed by laying a conductor in a predetermined shape parallel to the track of the linear motor car, but the propulsion coil of the linear motor car can also be used.

FIG. 4 shows an outline of the structure of a propulsion coil for a linear motor car, in which rectangular loop coils u, v, and w form motor poles. When a traveling wave magnetic field is formed by passing a positive or negative phase current of approximately 0 to 30 Hz through the loop coils u, v, and w, this acts on the electromagnet on the vehicle to generate thrust. Each loop coil u, v, w forming this propulsion coil has a periodic structure of P, and three conductors (11, 12, 12 in Fig. 3, 13).

In the operation of a linear motor car, the detection of the vehicle body position is required to adjust the field current as mentioned earlier, and if the loop coil is used as part of the inductive wireless line in the present invention, The benefits are great.

FIG. 5 shows an example of the case where the guided radio line according to the present invention is constructed using the propulsion coil of a linear motor car, and shows the loop coils u, v, w forming the propulsion coil and the loop coils u, v, w in parallel with these. A guided radio line is constituted by the provided linear conductor s.

[Embodiment of the Invention] An embodiment of the present invention will be described based on FIGS. 3 and 6.

FIG. 6 shows an example of the configuration of a signal processing device connected to the terminal of the line 15.
1-2, 21-3 are band pass wave generators, 22-1,
22-2, 22-3 are detectors, 23-1, 23-
2, 23-3 are AD converters, 24 is a digital computer, and 25 is a digital converter.

When a magnetic field is formed by the antenna 16 excited by a high frequency power source (not shown), a voltage is induced between each conductor 11, 12, 13, and 14 by this magnetic field.

Here, conductors 11 and 14, 12 and 14, 13
The signal processing device shown in FIG. 6 performs the following signal processing on the voltage induced between and 14.

The voltage V10 (z) between the conductors 11 and 14 is an AD signal whose noise voltage is removed by a bandpass detector 21-1, and then linearly detected by a detector 22-1.
The signal is guided to a converter 23-1 and converted into a digital quantity. Similarly, the voltage V20 (z) between the conductors 12 and 14 and the voltage V30 (z) between the conductors 13 and 14 are also applied to the bandpass wave detectors 21-2, 21-3, the wave detectors 22-2,
AD converter 23-2, 23-3 through 22-3
guided by.

From each AD converter 23-1, 23-2, 23-3, |V10(z)|, |V20(z)|, |V30
(z) | is output and the digital computer 24
guided by. Here, the calculation of equation (18) is digitally processed, the phase Φ'' of the positive phase voltage Vp'' (z) is obtained, and the moving body position z is displayed on the digital display 25. Moreover, it goes without saying that this amount can be used as a direct control signal. In addition,
The method of digitally calculating the value of tan-1 on the right side of equation (18) has already been established,
For example, a method using a series representation or a method of searching a numerical table is known.

The conductor shape of the guided radio line used in the present invention is a trapezoidal wave shape in FIG.
In FIG. 5, rectangular coils are connected in a chain, but the conductor shape may be triangular or rectangular. Further, the structure is not limited to a flat structure as shown in FIGS. 3 and 5, but may be a spiral structure.

In addition, although the explanation has been given using a linear motor car as an example of application of the present invention, the present invention is not limited to this, and it can be applied to railway vehicles, various new transportation systems, cranes, transportation vehicles, etc. that move along a fixed running route. It is widely applicable to detecting the position of moving objects.

[Effects of the Invention] As explained above, according to the present invention, the detection period of the moving body position can be made equal to the period P of the conductor shape of the guided radio line. That is, compared to the conventional method in which the detection period is P/2, the same detection period can be obtained even if the conductor period is halved. Therefore, manufacturing of the line becomes easy and the cost of the line can be reduced. In addition, if the period of the conductor is shortened, the size of the mobile tower-mounted antenna can be reduced proportionally.
The antenna can be easily attached to the vehicle body, and there is no need to provide a large cutout in the vehicle body, which eliminates concerns regarding the strength of the vehicle body.

When the present invention is applied to the position detection of a linear motor car, the ground propulsion coil can be used for multiple purposes as a guided radio line for position detection, and it can greatly contribute to the economicalization of the system configuration. .

[Brief explanation of drawings]

Fig. 1 is an explanatory diagram of the conventional method, Fig. 2 is an explanatory diagram of the relationship between the moving body position z and the phase difference, Fig. 3 is an explanatory diagram of the principle and one embodiment of the present invention, and Fig. 4 is an explanatory diagram of the linear motor. A schematic explanatory diagram of the ground propulsion coil of a car, FIG. 5 is a schematic explanatory diagram of the case where the ground propulsion coil of a linear motor car is used as the guided radio line of the present invention, and FIG. 6 is a signal processing device used in the present invention. FIG. 2 is an explanatory diagram of one embodiment of the invention. 11, 12, 13: conductor, 14: linear conductor,
15: Guided radio line, 16: Mobile tower-mounted antenna, 21-1, 21-2, 21-3: Band pass reactor wave detector, 22-1, 22-2, 22-3: Wave detector,
23-1, 23-2, 23-3: AD converter, 2
4: Digital computer, 25: Digital display device.

Claims (1)

[Claims] 1. Three conductors having a P periodic structure and arranged with each conductor shifted by P/3 in the longitudinal direction; An inductive radio line consisting of a conductor and a straight conductor is laid down, and when this inductive radio line is excited by a mobile tower-mounted antenna, waves are induced between each of the above three conductors and the straight conductor. Linearly detect the three voltages and calculate their envelopes (respectively |V10(z)
|, |V20(z)|, |V30(z)|),
Convert these quantities into digital quantities, z=(P/2π) tan ^-1 [(√3/2) {−|V20(z)|+
|V30(z)|｝/{|V10(z)|-(1/2)(|V20(z)|+|V30(z)|)}] The position of the moving object can be determined by calculating A moving body position detection method characterized by continuous detection at a period P.