JPS6332155B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a mobile body position detection method using guided radio.

2. Description of the Related Art It has been known for a long time to detect the position of a moving object such as a railway vehicle traveling along a certain track using guided radio, and various methods have been proposed so far.

An example of a conventional moving object position detection method will be described with reference to FIGS. 1 and 2.
In FIG. 1, 1, 2, and 3 are conductors, and a guided radio line 4 is formed by these conductors. 5 is an antenna mounted on a mobile object. Each of the conductors 1, 2, and 3 is bent in a planar shape into a waveform shape with a period P, and is arranged at intervals of P/3, so that the guided radio line 4 as a whole has a repeating structure with a period P.

Here, if the separation distance between the guided radio line 4 and the antenna 5 and the dimensions of the antenna 5 are appropriately selected and a high frequency current (50 to 200 kHz) is applied to the antenna 5, there will be no movement between the conductors 1, 2, and 3. As the body moves, a sinusoidal voltage is induced by electromagnetic induction.

Now, let the distance from the terminal of the guided radio line 4 to the antenna 5 be z, and each conductor 1-2, 2-3, 3-
The voltages induced between 1 and 1 are V ₁₂ , V ₂₃ and V ₃₁ respectively.
Then, these can also be expressed by the following equation.

V ₁₂ =kcos(2π/P)z V ₂₃ =kcos(2π/P){z+(P/3)} =kcos{(2π/P)z+(2π/3)} V ₃₁ =kcos(2π/P ) {z+(2P+3)} =kcos{(2π/P)z−(2π/3)} …(1) Here, k is the shape and dimensions of the inductive wireless line 4 and antenna 5, the separation distance between them, and the current It is a constant determined by the size and frequency of .

Now, the positive-sequence voltage V _p and negative-sequence voltage V _o for V ₁₂ , V ₂₃ , and V ₃₁ are defined by the following equations.

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) Substitute equation (1) for ( 2) By substituting and rearranging the equation, we get the following equation.

V _p = (3/2)ke ^j2 〓 ^z/P V _o = (3/2)ke ^-j2 〓 ^z/P …(3) If the phase difference between V _p and V _o is φ, then φ=∠V _p −∠V _o =4πz/P (4). Note that ∠ is a symbol representing the argument of a complex quantity.

This can be determined by placing a signal processing circuit at the terminal of the guided radio line 4 and performing analog calculations corresponding to equations (1) to (4) to obtain the phase difference φ=∠V _p −∠V _o . As shown in FIG. 2, this means that the moving body position z can be continuously known at a period of P/2.

However, this method relies on phase information of the voltage induced between each conductor, and there is a problem in that crosstalk occurs between the positive-phase and negative-phase voltages, resulting in a position detection error.

Furthermore, as shown in FIG. 3, when performing position detection using a guided radio line 4a having a repeating periodic structure with a period P _a and a guided radio line 4b having a repeating structure with a different period P _b , would also cause the same problem as mentioned above.

That is, even if the antenna 5 is connected to the guided radio line 4
a and 4b, and perform the same processing as described above to obtain the positive sequence voltage V _Pa for the inductive radio line 4a and the positive sequence voltage V _pb for the inductive radio line 4b, and taking the phase difference φ between them, the following is obtained. become that way.

φ=∠V _pa −∠V _pb = (2π/P _a )z − (2π/P _b )z = (2π/P _c )z …(5) Furthermore, P _c =P _a P _b /(P _b −P _a ), and P _a , P _b
is larger than either of the following.

In this way, by determining φ=∠V _pa −∠V _pb , the position of the moving object can be measured at a period of P _c , and the measurement period can be expanded.

However, in this method, the guided radio lines 4a and 4
There is a phase constant deviation in the positive phase line of b, and if these are respectively β _a and β _b , then at the terminal of the guided radio line, φ=∠V _pa −∠V _pb = (2π/P _c )z+( β _a −β _b )z (6), which includes a measurement error that increases with z.

An object of the present invention is to provide a moving body position detection method that can eliminate the position detection error caused by the difference in phase constants as described above.

In the position detection method of the present invention, three conductors having a repetition 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 the moving body changes. A guided radio line is laid along the path of the moving object, and when this guided wireless line is excited by an antenna mounted on the moving object, a sinusoidal waveform is generated between the conductors as the moving object moves, and Generate three voltages with a phase difference of 2π/3, find the square value of the envelope for each of these voltages, obtain three voltages proportional to the difference between these square values, and 3 voltages obtained by modulating the new carrier wave again with voltages
When the positive-sequence voltage V _p and negative-sequence voltage V _o for V _u , V _v , and V _w are defined by the following formula, V _p = V _u +e ^-j2 〓 ^/3 V _v +e ^j2 〓 ^/3 V _w V _o = V _u +e ^j2 〓 ^/3 V _{v +} e ^-j2 〓 ^/3 _{V wThe} moving object is It is characterized by detecting the position.

Further, the present invention provides a third conductor in which three conductors having a repetition period P are arranged shifted by P/3 so that a sinusoidal inter-conductor voltage is induced between each conductor as the position of the moving body changes. A first guided radio line and a second guided radio line that differs only in repetition period from the first guided radio line are laid along the moving path, and the first and second guided radio lines By exciting the line with an antenna mounted on a mobile object, a sinusoidal change occurs between each conductor of each system of the first and second guided radio lines as the mobile object moves, and a phase difference of 2π/3 is created. generate three voltages, calculate the square value of the envelope for each of these voltages, and calculate three voltages proportional to the difference between these square values for each system of the first and second inductive radio lines. The positive sequence voltage V a p and the voltage V ^a _u , V ^a _v , V ^a _w ^of the system of the first inductive radio line obtained by modulating the new carrier wave again with these three voltages _are obtained. The negative sequence voltage V ^a _o is defined by the following formula, V ^a _p = V ^a _u +e ^-j2 〓 ^/3 V ^a _v +e ^j2 〓 ^/3 V ^a _w V ^a _o = V ^a _u +e ^j2 〓 ^/3 V ^a _v +e ^-j2 〓 ^/3 V ^a wAlso, the voltage of _the second inductive radio line system V ^b _u , V ^b _v ,
When the positive sequence voltage V ^b _p and negative sequence voltage V ^b _o for V ^b _w are defined by the following formula, V ^b _p = V ^b _u +e ^-j2 〓 ^/3 V ^b _v +e ^j2 〓 ^/3 V ^b _w V ^b _o =V ^b _u +e ^j2 〓 ^/3 V ^b _v +e ^-j2 〓 ^/3 V ^b _wThe phase difference between the positive-sequence voltages or negative-sequence voltages for the first and second inductive radio line systems This feature is characterized in that the position of a moving object is detected based on the

The present invention detects the position of a moving object based only on the square value of the envelope of the voltage induced between each conductor, that is, amplitude information, and does not depend on phase information unlike conventional methods, so there is no error. Position detection becomes possible. Furthermore, in the present invention, since the guided radio line is constituted by three conductors, odd-order spatial harmonic components disappear in the signal processing circuit, thereby eliminating the cause of position detection errors. Note that when an inductive radio line is constructed with an even number of conductors, the even-order spatial harmonic components can disappear in the signal processing circuit;
Odd-numbered spatial harmonic components cannot be eliminated, and since the overlapping line constitutes the third line, it causes secondary crosstalk, which tends to cause position detection errors.

Hereinafter, the position detection method of the present invention will be explained in detail.

First, a position detection method using a guided radio line as shown in FIG. 1 will be explained.

By exciting the inductive radio line 4 with the antenna 5, the instantaneous voltages V ₁₂ , V ₂₃ , and V 31 induced in the conductors 1-2, 2-3, and _3-1 at the terminals of the inductive radio line 4 The value is as follows when the phase constant of the guided radio line 4 is taken into consideration.

V ₁₂ =k ₁ cos(2π/P)z ・e ^-j 〓 ^z・e ^j 〓 ^t V ₂₃ =k ₁ cos {(2π/P)z+(2π/3)} ・e ^-j 〓 ^z・e ^j 〓 ^t V ₃₁ = k ₁ cos {(2π/P)z−(2π/3)} ・e ^−j 〓 ^z・e ^j 〓 ^t …(7) Note that ω is the angular frequency of the antenna current.

Now, if each voltage V ₁₂ , V ₂₃ , V ₃₁ is linearly detected and the absolute value of its envelope is determined, and then its square value is determined, the following is obtained.

|V ₁₂ | ² =k ² ₁ cos ² (2π/P)z = (1/2)k ² ₁ [1+cos(4π/P)z] |V ₂₃ | ² =k ² ₁ cos ² {(2π/ P)z+(2π/3)} =(1/2)k ² ₁ [1+cos{(4π/P)z −(2π/3)}] |V ₃₁ | ² =k ² ₁ cos ² {(2π/ P)z−(2π/3)} =(1/2)k ² ₁ [1+cos{(4π/P)z +(2π/3)}] …(8) Then, V _eu =k ₂ (|V ₁₂ | ² − | V ₂₃ | ² ) V _ev = k ₂ ( | V ₂₃ | ² − | V ₃₁ | ² ) V _ew = k ₂ ( | V ₃₁ | ² − | V ₁₃ | ² ) …(9) By defining V _eu , V _ev , and V _ew respectively by and substituting equation (8) into equation (9), the following equation is obtained.

Note that k ₂ is a constant.

V _eu = (√ 3/2)k ² ₁ k ₂・cos {(4π/P)z+(π/6)} V _ev = (√ 3/2)k ² ₁ k ₂・cos {(4π/P )z+(π/6) −(2π/3)} V _ew =(√ 3/2)k ² ₁ k ₂・cos{(4π/P)z+(π/6) +(2π/3)}... (10) Now, if we modulate the new carrier wave e ^j 〓′ ^t again with V _eu , V _ev , and V _ew and let these be V _u , V _v , and V _w , respectively, we obtain the following equation.

V _u = (√ 3/2)k ² ₁ k ₂・cos {(4π/P)z+(
π/6)}・e ^j 〓′ ^t V _v = (√ 3/2)k ² ₁ k ₂・cos {(4π/P)z+(
π/6)−(2π/3)}・e ^j 〓′ ^t V _w = (√ 3/2)k ² ₁ k ₂・cos {(4π/P)z+(
π/6) + (2π/3)}・e ^j 〓′ ^t …(11) The positive sequence voltage V _p and negative sequence voltage _Vo for V _u , V _v , and V _w are expressed as V _p =V _u +e ^-j2 〓 ^/3 V _v +e ^j2 〓 ^/3 V _w V _o =V _u +e ^j2 〓 ^/3 V _v +e _-j2 〓 _/3 V _w …Defined by (12), and convert formula (11) into (12) By substituting into the equation, the following equation is obtained.

V _p = (3√ 3/4)k ² ₁ k ₂・e ^-j [ ⁽⁴ 〓 ^/P)z+( 〓 ^/6) ]
・e ^j 〓′ ^t V _o = (3√ 3/4)k ² ₁ k ₂・e ^j [ ⁽⁴ 〓 ^/P)z+( 〓 ^/6) ]・
e ^j 〓′ ^t …(13) Find the phase difference ∠V p between the positive sequence voltage V _p and the carrier wave e ^j 〓′ ^t and the phase difference ∠V _o between _{the negative sequence voltage Vo and} the carrier wave e ^j 〓′ ^t The following relationship is obtained.

−∠V _p =∠V _o = (4π/P)z+(π/6)
...(14) In other words, ∠V _p and ∠V _o show a change of 2π every time z increases by P/2, so ∠V _p or ∠V _o
By measuring this, the position of the moving object can be detected periodically and continuously at a period of P/2.

In the above operation, since it depends only on the amplitude of the inter-conductor voltage and is independent of the phase constant β of the guided radio line, error-free position detection is possible.

Next, as shown in FIG. 3, a case will be described in which a guided radio line 4a with a period P _a and a guided radio line 4 b with a period P _b are used.

The voltages induced between the respective conductors of the guided radio lines 4a and 4b are subjected to the same signal processing as described above, and the voltages V ^au , _{V av} ^, of the system of the guided radio lines 4a are determined.
The positive sequence voltage V ^{a p} and the negative sequence voltage V ^a _{o for} V a _w are defined by the following equations.

V ^a _p =V ^a _u +e ^-j2 〓 ^/3 V ^a _v +e ^j2 〓 ^/3 V ^a _w V ^a _o =V ^a _u +e ^j2 〓 ^/3 V ^a _v +e ^-j2 〓 ^/3 V ^a _w …( 15) In addition, the system voltages V ^b _u , V ^b _v ,
The positive sequence voltage V ^b _p and ^the negative sequence voltage V ^b _o with respect to V b _w are defined by the following equations.

V ^b _p =V ^b _u +e ^-j2 〓 ^/3 V ^b _v +e ^j2 〓 ^/3 V ^b _w V ^b _o =V ^b _u +e ^j2 〓 ^/3 V ^b _v +e ^rj2 〓 ^/3 V ^b _w …(16 ) Negative phase voltage for the system of the guided radio line 4a
Taking the phase difference between V ^a _o and the negative phase voltage V ^b _o for the system of the guided radio line 4b is as follows.

∠V ^a _o −∠V ^b _o = (4π/P _a )z − (4π/P _b )z = (2
π/P _c )z...(17) Here, P _c =P _a P _b /2(P _a −P _b ).

Therefore, by measuring ∠V _oa −∠V _{ob ,} the position of the moving body can be periodically and continuously detected with a period of P _c . Further, even if there is a difference in phase constant between the two systems of guided radio lines 4a and 4b, no adverse effect appears on measurement accuracy.

Note that similar results can be obtained by using the phase difference ∠V ^a _p −∠V ^b _p between the positive-sequence voltages.

FIG. 4 shows an example of a signal processing circuit connected to the terminal of the guided radio line.

6a, 6b, 6c are each conductor 1 of the guided radio line,
Terminals 7a, 7b, connected to 2 and 3, respectively.
7c is a buffer amplifier, 8a, 8b, 8c are band pass filters, 9a, 9b, 9c are square law detection circuits, 1
0a, 10b, 10c are subtraction circuits, 11a, 11
b, 11c are modulation circuits, 12b is a +120° phase circuit, 12c is a -120° phase circuit, 13 is an adder circuit,
14 is a carrier wave power supply, and 15 is a phase meter.

The voltages V ₁₂ , V ₂₃ , and V ₃₁ induced in each conductor 1-2, 2-3, and 3-1 are applied to buffer amplifiers 7a and 7, respectively.
b, 7c, the noise voltage is removed by filters 8a, 8b, 8c, and square law detection circuits 9a, 9b, 9c
reach.

The output voltages of the square law detection circuits 9a, 9b, and 9c are proportional to |V ₁₂ | ² , |V ₂₃ | ² , and |V ₃₁ | ^2, respectively, and are led to the next subtraction circuits 10a, 10b, and 10c, and from this circuit |V ₁₂ | ² − |V ₂₃ | ² , |V ₂₃ |
A voltage proportional to ² −|V ₃₁ | ² , |V ₃₁ | ² −|V ₁₂ | ² is output.

In the modulation circuits 11a, 11b, and 11c, the carrier wave e ^j 〓′ ^t guided from the carrier wave power source is modulated again,
The output from the modulation circuit 11a is sent directly to the addition circuit 1.
3, and the outputs from modulation circuits 11b and 11c are input to phase circuits 12a and 12C, respectively.
After receiving a phase shift of 120° and -120°, adder circuit 1
3 is input.

The adder circuit 13 outputs a negative phase voltage V _o ,
The carrier wave from the carrier wave power supply 14 in the phase meter 15
The moving body position z can be determined by taking the phase difference between e ^j 〓′ ^t and the negative phase voltage _Vo .

When the method of the present invention is used in a place where there is severe inductive noise, it is necessary to insert filters 8a, 8b, and 8c on the input side, but in this case, the conventional method that directly processes the received voltage is When the phase characteristics of the filters 8a, 8b, and 8c change due to ambient temperature or changes over time, the phase changes directly cause position detection errors.

However, in the method of the present invention, the filters 8a, 8
Even if voltages b and 8c are used, the fluctuations in the amplitude of each voltage are minute, so position detection with almost no error is possible.

Note that the structure of the guided radio line used in the present invention is not limited to the trapezoidal wave shape as shown in FIG. It may be a spiral conductor structure.

The number of conductors is not limited to three, but as long as it is an odd number of three or more, the same result can be obtained by performing the same process on the voltage induced between each adjacent conductor.

As explained above, since the present invention detects the position based only on amplitude information, it is possible to detect the position without error. Furthermore, by using two sets of guided radio lines with different periodic structures, it is possible to expand the measurement range.

[Brief explanation of the drawing]

Figure 1 is an explanatory diagram of a position detection method using a set of guided radio lines, and Figure 2 is a diagram showing the position of the moving object z and ∠V _p −
A graph showing the relationship of ∠V _o , FIG. 3 is an explanatory diagram of a position detection method using two sets of guided radio lines, and FIG. 4 is an explanatory diagram of an example of a signal processing circuit used in the present invention. 1, 2, 3... Conductor, 4, 4a, 4b... Guided radio line, 5... Mobile body mounted antenna.

Claims (1)

[Claims] 1. The repetition period P is set so that a sinusoidal inter-conductor voltage is induced between each conductor as the position of the moving body changes.
A guided radio line consisting of three conductors shifted by P/3 is laid along the moving route, and by exciting this guided radio line with an antenna mounted on the moving body, each of the above-mentioned conductors In between, it changes in a sinusoidal manner as the moving object moves, and 2π/3
Generate three voltages with a phase difference of When the positive-sequence voltage V _p and the negative-sequence voltage V _o for the three voltages V _u , V _v , and V _w obtained by modulating the new carrier wave again are defined by the following formula, V _p = V _u + e ^-j2 〓 ^/3 V _v +e ^j2 〓 ^/3 V _w V _o =V _u +e ^j2 〓 ^/3 V _v +e ^-j2 〓 ^/3 V _wFrom positive sequence voltage V _p or negative sequence voltage _Vo and carrier wave power supply A moving body position detection method that detects the position of a moving body based on a phase difference with a reference phase signal that is guided. 2 The repetition period P is set so that a sinusoidal inter-conductor voltage is induced between each conductor as the position of the moving body changes.
A first guided radio line formed by arranging three conductors shifted by P/3, and a second guided radio line that differs only in repetition period from the first guided radio line, are used when a mobile object is running. By exciting the first and second guided radio lines with an antenna mounted on a mobile object, a moving object is generated between each conductor of each system of the first and second guided radio lines. It changes sinusoidally as it travels, and has a 2π/
Three voltages having a phase difference of 3 are generated, the squared value of the envelope is determined for each of these voltages, and the squared value is proportional to the difference between these squared values for each system of the first and second guided radio lines. The voltage V ^a _u of the first guided radio line system obtained by obtaining three voltages and modulating a new carrier wave again with these three voltages,
Positive sequence voltage _V ^{a p} and negative sequence voltage V ^a _o for V ^a v _, V a _w
is defined by the following formula, V ^a _p =V ^a _u +e ^-j2 〓 ^/3 V ^a _v +e ^j2 〓 ^/3 V ^a _w V ^a _o =V ^a _u +e ^j2 〓 ^/3 V ^a _v +e ^-j2 〓 ^/3 V ^a _wAlso , the voltage V ^b _u of the system of the second inductive radio line,
Positive sequence voltage V ^b _p and negative sequence voltage V ^b _o for V ^b _{v ,} V ^b w
When defined by the following formula, V ^b _p =V ^b _u +e ^-j2 〓 ^/3 V ^b _v +e ^j2 〓 ^/3 V ^b _w V ^b _o =V ^b _u +e ^j2 〓 ^/3 V ^b _v +e ^-j2 〓 ^/3 V ^b _wMoving object position detection characterized in that the position of the moving object is detected based on the phase difference between positive phase voltages or negative phase voltages of the first and second guided radio line systems. method.