JPH0450539B2 - - 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 magnetic field current accordingly.

Currently, a method using guided radio is considered to be a promising means to meet this demand.
This method consists of two methods: a method in which the voltage induced in the guided radio line by the excitation of an antenna mounted on a mobile object is processed on the ground, and the position of the moving object is directly detected from this (ground detection), and a method in which the position of the moving object is directly detected from the voltage induced on the guided radio line by the excitation of the antenna mounted on the moving object. There is a method (on-vehicle detection) in which the voltage is received by an antenna mounted on a mobile body, the position is detected by signal processing on the mobile body, and this is encoded and transmitted wirelessly to a ground base station.

Although the ground detection method has the advantage of directly obtaining control signals on the ground, it has the disadvantage of causing measurement errors when the amount of crosstalk in the guided radio line is large.
In addition, while the on-vehicle detection method does not have any problem with crosstalk in the guided radio line, it encodes position information.
This needs to be transmitted wirelessly, which has the disadvantage of complicating the system, so it is difficult to compare the superiority of the two methods.

A position detection method currently proposed as an on-vehicle detection method will be described with reference to FIGS. 1 and 2.

In Figure 1, Figure 1 a is a plan view, Figure 1 b
is a sectional view taken along line A-A'. 1 and 2 are conductors, 3 is an inductive radio line formed by conductors 1 and 2, and 4-
1 and 4-2 are antennas mounted on a mobile object.

The conductors 1 and 2 are bent into a waveform shape with a period P on a plane, and are arranged offset from each other by P/3. Further, frame-shaped loop coils are used as the antennas 4-1 and 4-2, and are fixed on the moving body with a mutual shift of P/4.

When a high frequency current of 50 to 200 KHz is supplied from the ground transmitter 5 to the line 3, an induced magnetic field is formed around the line 3, and a voltage is induced in the antennas 4-1 and 4-2.

The amplitude of the voltage induced in each antenna 4-1, 4-2 can be controlled by appropriately selecting the distance between the line 3 and the antennas 4-1, 4-2 and the dimensions of the antennas 4-1, 4-2. z (distance from the terminal of the line 3 to the antenna 4-1) can be made sinusoidal.

Here, the reason why the envelope of the antenna induced voltage has a sinusoidal shape with respect to z will be explained.

As shown in FIG. 7, the corrugated conductor 1a and the conductor 1b
Consider a line 33 consisting of. FIG. 7a is a plan view, and FIG. 7b is a sectional view taken along line A-A'. Currents I and -I are applied to the waveform conductor 1a as an outgoing path and the conductor 1b as a return path, respectively. P is the conductor pitch. The antenna 32 uses a frame-shaped loop coil, and the line 33
Move it in the z direction while maintaining the height h. Then, the induced voltage Va(z) of the antenna 32 is
It is a periodic function with respect to z having a period of P. When the length L of the antenna 32 and the distance h between the antenna 32 and the line 33 are both extremely small, as shown in FIG. This includes high-order spatial harmonic components.

As L and h are gradually increased, the higher-order spatial harmonics in Va(z) rapidly decrease, and L is P/7 to P/5 and h is twice the line width d. It is known that if the above is taken, Va(z) will consist almost only of sine wave components. This is because as L increases, the electromotive force corresponding to the harmonic component tends to cancel out within the antenna, and as h increases, the magnetic flux corresponding to the harmonic component rapidly decreases. It is being said.

For this reason, in Fig. 1, the voltages induced in antennas 4-1 and 4-2 are respectively
If V ₁ (z) and V ₂ (z), then V ₁ (z)=kcos2πz/P V ₂ (z)=kcos2π(z+P/4)/P=kcos {(2πz/P)+π/2} ...(1) K: Can be expressed as a constant.

Here, when the following relationship holds between the two voltages V ₁ and V ₂ , V ₁ = V _p , V ₂ = V _p e ^j 〓 ^/2 (1-1), V ₁ and V ₂ are It is called the positive sequence voltage of the phase equation, and its value is represented by V _p , and when the relationship of V ₁ = V _o , V ₂ = V _o e ^-j 〓 ^/2 ... (1-2) holds, V ₁ , V ₂ is called the two-phase negative phase voltage, and its value is represented by V _o . (By convention, V _p is sometimes called the negative sequence voltage, and V _o is sometimes called the positive sequence voltage.) In general, any two voltages
V ₁ and V ₂ can be expressed as the sum of a positive sequence voltage and a negative sequence voltage. That is, V ₁ =V _p ′+V _o ′ V ₂ =V _p ′e ^j 〓 ^/2 +V _o ′e ^-j 〓 ^/2 ...(1-3) This immediately results in 2V _p ′=V ₁ +e ^-j 〓 ^/2 V ₂ 2V _o ′=V ₁ +e ^j 〓 ^/2 V ₂ ...(1-4) is derived.

Here, for convenience of calculation, 2V _p ′ is the positive sequence voltage
V _p (z), 2V _o ′ are expressed as the negative sequence voltage V _o (z), and the positive sequence voltage
V _p (z) and negative phase voltage V _o (z) are defined by the following equations.

V _p (z)＝V ₁ (z)＋e ^-j 〓 ^/2 V ₂ (z) V _o (z)＝V ₁ (z)＋e ^j 〓 ^/2 V ₂ (z) ……(2) (1 ), V ₁ (z) = (1/2) k (e ^j2 〓 ^z/P +e ^-j2 〓 ^z/P ) V ₂ (z) = (1/2) k (e ^j2 〓 ^z/P+j 〓 ^/2 +e ^-j2 〓 ^z/Pj 〓 ^/2 )
...(2-1) By substituting the relationship of the above equation (2-1) into equation (2), the following equation is obtained.

V _p (z)＝(1/2)k{e ^j2 〓 ^z/P+ ＋e ^-j2 〓 ^z/p ＋e ^-j 〓 ^/2 (e _j2 〓 _z/p+j 〓 _/2 ＋ e ^-j2 〓 ^{z /Pj} 〓 ^/2 )｝ =Ke ^j2 〓 ^z/P V _o (z)＝(1/2)k{e ^j2 〓 ^z/P +e ^-j2 〓 ^z/P +e ^j 〓 ^/2 (e _j2 〓 _{z /P+j} 〓 _/2 +e ^-j2 〓 ^z/Pj 〓 ^/2 )} =Ke ^-j2 〓 ^z/P ……(3) The phase difference between V _p (z) and V _o (2) is expressed as Φ(z ), then Φ(z)=∠V _p (z)−∠V _o (z) =4πz/P...(4) (∠: symbol meaning declination angle).

In other words, Φ(z) is defined as z is P/ as shown in Figure 2.
Every increase by 2 indicates a linear increase of 2π, and by measuring Φ(z), the position of the moving object can be continuously measured at a period of P/2.

Therefore, when applying this to the position detection of a linear motor car, P is equal to 2 of the distance between motor poles.
The desired purpose can be achieved by doubling the number of lines and laying the line in a position synchronized with the motor pole.

However, the above method has the following drawbacks.

In other words, the period P of each conductor 1, 2 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, so Therefore, the conductor period P must be approximately 12 m.

For this reason, manufacturing of the line 3 may become 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 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 gist of the present invention is that a conductor is formed by repeating the same shape at a constant period P along the travel path of a moving object;
A guided radio line consisting of a straight conductor parallel to this conductor is laid, while a P/3
Three antennas _are mounted at intervals of )｜,｜V ₂ (z)
|, |V ₃ (z)|) and convert these quantities into digital quantities, Z=(P/2π)tan ^-1 [(√3/2){−|V ₂ (z) | + | V ₃ (z) | | / { | V ₁ (z) | − (1/2) ( | V ₂ (z) + |
V ₃ (z)|}] The purpose of this method is to continuously detect the position of a moving object at a period P by performing the calculation.

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

In Figure 3, Figure 3a is a plan view and Figure 3b is a plan view.
is a sectional view taken along line A-A'. 11 and 12 are conductors, respectively. The conductor 11 is bent into a waveform shape with a period P, and the conductor 12 is arranged in a straight line in parallel with the conductor 11, thereby forming an inductive radio line 13. There is. 14-1, 14-2, 1
4-3 are mobile-mounted antennas,
Each antenna is fixed to the moving body at an interval of P/3.

When a high frequency current of 50 to 200 KHz is supplied from the ground transmitter 15 to the line 13, an induced magnetic field is formed around the line 13, and a voltage is induced in the antennas 14-1, 14-2, and 14-3.

The guided radio line 13 in FIG. 3 includes a line 43 that uses the conductor 2a shown in a in FIG.
It can be understood as a combination with the line 53 whose return route is b.

The voltage induced in the antenna from the line 43 in FIG. 9a has a sinusoidal waveform as described above, and has a waveform as shown in FIG. 10a. A voltage with a uniform amplitude as shown in FIG. 10b is induced from the line 53 in FIG. 9b, and when both are combined, a voltage having a waveform as shown in FIG. 10c is obtained. Expressed mathematically, it is as follows.

V(z)=k ₁ {1+k ₂ cos2πz/P}...(4-1) However, k ₁ and k ₂ are constants.

In this way, if the distance from the terminal of the line 13 to the antenna is z, each of these antennas 14-
Voltage V ₁ (z) induced in 1, 14-2, 14-3,
V ₂ (z) and V ₃ (z) are expressed as shown below.

V ₁ (z)=k ₁ {1+k ₂ cos2πz/P} V ₂ (z)=k ₁ {1+k ₂ cos2π(z+P/3)/P} V ₃ (z)=k ₁ {1+k ₂ cos2π(z+2P/ 3)/P} K ₁ , K ₂ : constants (5) Since 0<k ₂ <1, the right side of equation (5) is always positive.

Therefore, by linearly detecting V ₁ (z), V ₂ (z), and V ₃ (z), their envelopes |V ₁ (z)|, |V ₂ (z)|, |V ₃ (z) )| is calculated as follows.

｜V ₁ (z)｜=V ₁ (z) ｜V ₂ (z)｜=V ₂ (z) ｜V ₃ (z)｜=V ₃ (z) ...(6) Here, the high frequency ω The new carrier wave of ₀ is modulated by each voltage in equation (6), and they are respectively V _u ′(z), V _v ′(z),
If V _w ′(z), then the following equation is obtained.

V _u ′(z) =｜V ₁ (z)｜e ^j 〓 ^ot =k ₁ (1+k ₂ cos2πz/P)・e ^j 〓 ^ot V _v ′(z) =｜V ₂ (z)｜e ^j 〓 ^ot = k ₁ [1 + k ₂ cos2π (z + P / 3) / P] ・e _j 〓 _pt V _w ′(z) = |V ₃ (z) | e ^j 〓 ^ot = k ₁ [1 + k ₂ cos2π (z - P /3)/P] ・e _j 〓 _pt ……(7) Here, generally any three voltages V _u ′, V _v ′, V _w ′
It is known that can be expressed as the sum of positive-sequence voltage V _p , negative-sequence voltage V _o and zero-sequence voltage V ₀ as shown in the following equation.

V _u ′＝V _p ＋V _o ＋V ₀ V _v ′＝V _p e ^j2 〓 ^/3 ＋V _o e ^-j2 〓 ^/3 ＋V ₀ V _w ′＝V _p e ^-j2 〓 ^/3 ＋V _o e ^j2 〓 ^/3 +V ₀ ...(7-1) 1+e ^j2 〓 ^/3 +e ^-j2 〓 ^/3 =0 ...(7-2) If we focus on the relationship, we can derive the following equation from equation (7-1). .

3V _p =V _u ′+e ^-j2 〓 ^/3 V _v ′ +e ^j2 〓 ^/3 V _w ′ 3V _o =V _u ′+e ^j2 〓 ^/3 V _v ′ +e ^-j2 〓 ^/3 V _w ′ 3V ₀ =V _u ′＋V _v ′＋V _w ′ ...(7-3) Here, for convenience of calculation, 3V _p is the positive sequence voltage.
V _p ′(z) and 3V _o are expressed as negative sequence voltage V _o ′(2), and the positive sequence voltage V _p ′(z) and negative sequence voltage V _o ′(z) are defined by the following equation.

V _p ′(z)=V _u ′(z)+e ^-j2 〓 ^/3 V _v ′(z) +e ^j2 〓 ^/3 V _w ′(z) V _o ′(z)=V _u ′(z)+e ^j2 〓 ^/3 V _v ′(z) +e ^-j2 〓 ^/3 V _w ′(z) ...(8) The following formula is derived from the mathematical formula, cos2πz/P = (e ^j2 〓 ^z/P +e ² 〓 ^z/P )/2 cos (2πz/P+2π/3) = (e ^j2 〓 ^z/P+j2 〓 ^/3 +e ^-j2 〓 ^z/P-j2 〓 ^/3 )/2 cos (2πz/P-2π /3) = (e ^j2 〓 ^z/P-j2 〓 ^/3 +e ^-j2 〓 ^z/P+j2 〓 ^/3 )/2 ......(8-1) This equation (8-1) is transformed into equation (7) and then
Substituting equation (7) into equation (8) and focusing on the relationship 1 + e ^j2 〓 ^/3 + e ^-j2 〓 ^/3 = 0 ... (8-2), we can obtain the equation (7) which corresponds to the zero-sequence voltage. The first term in the braces on the right side of each equation disappears, and the following equation is obtained.

V _p ′(z) = (3/2)k ₁ k ₂ e ^(j2 〓 ^z/P)+j 〓 ^ot V _o ′(z)= (3/2)k ₁ k ₂ e ^-(j2 〓 ^{z /P)+j} 〓 ^ot ……(9) By comparing V _p ′(z) or V _o ′(z) with the reference phase signal derived from the carrier wave power source, Φ′(z) of the following equation is obtained.
can be found.

Φ′(z)=∠V _p ′(z)−∠e ^j 〓 ^ot =−(∠V _o ′(z)−∠e ^j 〓 ^ot ) =2πz／P ……(10) That is, Φ′( z), the moving body position z
can be known continuously with a period of P.

Note that the right-hand side of each equation (5) actually contains some spatial harmonic components, but by using three antennas, harmonics of the 3rd, 9th, and 15th orders, which are integral multiples of 3, are This component disappears during the signal processing of equation (8), which has the advantage of improving position detection accuracy compared to the method using two antennas as shown in FIG.

Although the above method is an analog method, it is possible to detect the moving body position z using a digital method. That is, from equations (7) and (8), V _p ′(z) = {｜V ₁ (z)｜+e ^-j2 〓 ^/3 ｜V ₂ (z)｜ +e ^j2 〓 ^/3 ｜V ₃ (z )｝e ^jwot ……(10−1), and Φ′(z)＝∠V _p ′(z)−∠e ^jwot =∠｛｜V ₁ (z)｜+e ^-j2 〓 ^/3 ｜V ₂ (z)｜＋e ^j2 〓 ^/3 ｜V ₃ (
z)} =∠{|V ₁ (z)｜＋(−1/2−j√3/2)｜V ₂ (z)
｜+(−1/2+j√3/2)｜V ₃ (z)｜｝ =∠〔｜V ₁ (z)｜+(1/2)｜｜V ₂ (z)｜＋｜V ₃ (z )｜｝
+j (√3/2) {−|V ₂ (z)|+|V ₃ (z)|} =tan ^-1 [(√3/2{−|V ₂ (z)|+|V ₃ (z) )}/{
｜V ₁ (z)｜(1/2) (｜V ₂ (z)｜＋｜V ₃ (z)｜)}]……(1
1) Therefore, Z=(P/2π)tan ^-1 [(√3/2){−|V ₂ (z)| +|V ₃ (z)|}/{|V ₂ (z)| −(1/2)(｜V ₂ (z)｜＋
|V ₃ (z)|)}]...(12) In this way, |V ₁ (z)|, |V ₂ (z)|, and |V ₃ (z)| can be digitally processed. Therefore, it is possible to detect the moving body position z.

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 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 current of about 0 to 30 Hz in positive or negative phase through the loop coils u, v, and w,
This acts on the electromagnets on the vehicle, creating thrust. Each loop coil u, v, forming this propulsion coil,
Since w has a periodic structure of P shifted by P/3, either of these can be used in correspondence with the conductor 11 in FIG.

In the operation of a linear motor car, the detection of the vehicle body position is required to adjust the magnetic field current, as mentioned earlier, and if the loop coil can be used as part of the inductive wireless line in the present invention, there will be an advantage. big.

FIG. 5 shows an example in which a propulsion coil of a linear motor car is used as an inductive radio line of the present invention.

15 is a transmitter, 16 is a transformer, 17, 18, 1
9 is a connecting conductor of each loop coil u, v, w, 12
is a straight conductor. By connecting the conductors 17, 18, and 19 as shown in the figure, it is possible to form an inductive radio line with the loop coil u as the outward path and the straight conductor 12 as the return path, and position detection can be performed in the same way as the method explained in FIG. 3. It can be performed.

[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 mounted on a mobile object, and includes 20-1, 20-2,
20-3 is a buffer amplifier, 21-1, 21-2, 2
1-3 is a band pass filter, 22-1, 22-2,
22-3 is a detector, 23-1, 23-2, 23-
3 is an A/D converter, 24 is a digital computer, and 25 is a digital display device.

Transmitter 1 provided at the terminal of guided radio line 13
When a high frequency current is supplied through conductor 11 as an outgoing path and conductor 12 as a return path, a voltage is induced in the antennas 14-1, 14-2, and 14-3 mounted on the moving body.

The voltage induced in each antenna is transferred to the buffer amplifier 2
0-1, 20-2, 20-3, and is converted into an unbalanced voltage by bandpass filters 21-1, 21-2,
21-3 removes noise components, and then linear detection is performed by detectors 22-1, 22-2, 22-3, and then A/D converters 23-1, 23-
2, 23-3, where it is converted into a digital quantity.

Each A/D converter 23-1, 23-2, 23-3
|V ₁ (z)|, |V ₂ (z)|, and |V ₃ (z)| are outputted and guided to the digital computer 24. Here, the calculation of equation (11) or equation (12) is digitally processed and displayed on the digital display device 25.

The calculations in equations (11) and (12) are all four arithmetic operations and can be processed extremely easily. Additionally, calculations for calculating tan ^-1 using a computer have already been established, including those that use series and those that search numerical tables.

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, but it is also applicable to vehicles that move along a fixed running route such as railway vehicles, various new transportation systems, cranes, and transportation vehicles. It is widely applicable to body position detection.

[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 price of the line can be reduced. In addition, if the period of the conductor is shortened, the size of the antenna mounted on a mobile object can be reduced in proportion to this.
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 the drawing]

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, and Figs. 3, 9, and 10 are explanatory diagrams of the principle and one embodiment of the present invention. Figure 4 is a schematic explanatory diagram of the ground propulsion coil of a linear motor car, Figure 5 is a schematic 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 Figure 6 is a schematic diagram of the ground propulsion coil of the linear motor car. Explanatory diagram of an embodiment of the signal processing device used in the invention, No. 7
FIG. 8 and FIG. 8 are explanatory diagrams of the induced voltage induced in the antenna. 11: bent conductor, 12: straight conductor, 1
3: Guided radio line, 14-1, 14-2, 14-
3: Mobile-mounted antenna, 20-1, 20-2,
20-3: Buffer amplifier, 21-1, 21-2, 2
1-3: band pass filter, 22-1, 22-2,
22-3: Detector, 23-1, 23-2, 23-
3: A/D converter, 24: Digital computer, 25: Digital display device.

Claims (1)

[Claims] 1. A guided radio line consisting of a conductor repeating the same shape at a constant period P and a linear conductor parallel to this conductor is laid along the travel path of a moving object, On the other hand, the mobile object is equipped with three antennas at intervals of P/3, and when a high-frequency current is passed through the inductive radio line, the voltages induced in each of the antennas are linearly detected, and the envelope ( |V ₁ (z)|, |V ₂ (z)|, |V ₃ (z)|) and convert these quantities into digital quantities, Z=(P/2π) tan ^-1 [(√3/2) {−|V ₂ (z)| +|V ₃ (z)|}/{|V ₁ (z)|−(1/2) (|V ₂ (z)+ ｜
V ₃ (z) |