JPH0235266B2 - - 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 motor poles), and is laid with a shift of 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)=k cos2πz/P・e ^- 〓 ^z V23(z)=k cos2π(z+P/3)/P・e ^- 〓 ^z V31(z)= k cos2π(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 + cos4
πz/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, modulate the carrier wave of angular frequency ωo with each value of equation (5), and convert these values into 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.

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 wave shape with respect to z, as shown in equation (1), and therefore the length L of the antenna 5 is P /7 to P/5 (1.7 to 2.4 m when P=12 m), which is extremely large. 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
, and each conductor has a periodic structure of P/
An inductive radio line is constructed, consisting of three conductors spaced apart by 3 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 to find their envelopes, and the carrier waves of the same amplitude and phase derived from the new carrier wave power source are modulated by each of the above envelopes. The position of the moving object is continuously determined with a period P by determining the positive phase or negative phase components of the three voltages obtained by The purpose is to detect

That is, the present invention is characterized in that the position of a moving object is detected by using not only the positive-phase component and the negative-phase component of the voltage induced in the line, but also the zero-phase component.

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 of 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
)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 ……(10) 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, the above voltage is linearly detected at the starting end of the line 15, and its envelope is determined as shown in the following equation.

｜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 ......(11) Here, the new carrier wave of angular frequency ωo is modulated with each voltage in equation (11), and each is Vu''(z),
Assuming Vv″(z) and Vw″(z), the following equation is obtained.

Vu″(z)=｜V10(z)｜e ^j 〓 ^ot =k1(1+k2cos2
πz/P)・e ^- 〓 ^z+j 〓 ^ot Vv″(z)=｜V20(z)｜e ^j 〓 ^ot =k1[1+k2cos2
π(z+P/3)/P]・e ^- 〓 ^z+j 〓 ^ot Vw″(z)=｜V30(z)｜e ^j 〓 ^ot =k1[1+k2cos2
π(z+2P/3)/P]・e ^- 〓 ^z+j 〓 ^ot ......(12) Perform the following signal processing on 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) ......(13) The following equation can be obtained immediately from equations (12) and (13).

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
......(14) 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
(15) That is, by measuring Φ'', 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 and 23-3 are modulators, 24-2 and 24- are phase shifters, 25 is a carrier power source, 26 is an adder, and 27 is a phase meter.

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.

Noise voltage is removed from the voltage V10 (z) between the conductors 11 and 14 by a bandpass detector 21-1, and then linearly detected by a detector 22-1 and guided to a modulator 23-1. Here, the carrier wave of angular frequency ωo guided from the carrier wave power source 25 is amplitude-modulated.
Note that the action in the detector 22-1 corresponds to the first equation of equation (11), and the action in the modulator 23-1 corresponds to the calculation in equation (12).

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 and the wave detectors 22-2, 2.
2-3 to modulators 23-2 and 23-3, and amplitude modulates the carrier wave.

Next, the outputs of the modulators 23-1, 23-2, and 23-3 are guided to the adder 26, but the output of the modulator 23-1 is directly guided to the adder 26, whereas the output of the modulator 23-2 is guided directly to the adder 26. , 23-3 are outputted from phase shifter 2, respectively.
After undergoing phase shifts of -120° and 120° at 4-2 and 24-3, the signals are led to the adder 26. The action of the adder 26 corresponds to the operation of the first equation of equation (13),
The output is Vp″(z) in equation (14).

The output of the adder 26 is guided to the phase meter 27 together with the reference phase signal derived from the carrier wave power supply 25, the phase difference between the two is indicated, and the position z of the moving object is continuously measured every period P through this value. Can be done. In the phase meter 27, calculations corresponding to equation (15) are performed.

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: Modulator, 24-
2, 24-3: Phase shifter, 25: Carrier wave power supply, 2
6: adder, 27: phase shift meter.

Claims (1)

[Claims] 1 Along the travel path of the moving body, three conductors having a periodic structure of P and each conductor are arranged shifted by P/3 in the longitudinal direction, and a straight line parallel to these three conductors. An inductive radio line consisting of a conductor has been laid, and by exciting this inductive radio line with a mobile tower antenna, the three voltages induced between each of the three conductors and the linear conductor are linearly generated. Detect and find its envelope, modulate the carrier wave of the same amplitude and same phase derived from a new carrier wave power source with each of the above envelopes, find the positive phase or negative phase component of the three voltages obtained, and calculate the above carrier wave. A moving body position detection method characterized in that the position of a moving body is continuously detected at a period P by comparing the phase of a reference phase signal derived from a power source and the above-mentioned normal phase or negative phase component.