JP2012121400A - On-vehicle train control apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve resonance frequency detection accuracy by preventing erroneous detection of the resonance frequency of a ground coil without using a feedback oscillation circuit.SOLUTION: The on-vehicle train control apparatus includes a signal creation unit 12, a pickup coil 11 and a signal detection unit 13. The signal creation unit 12 creates a frequency sweeping signal by sweeping a frequency in an allowable variation range including the resonance frequency of a resonator in a specific time cycle. The pickup coil 11 has a first coil 11a that receives the frequency sweeping signal, and a second coil 11b that obtains the signal by the electromagnetic connection with the first coil, and obtains the signal component corresponding to the resonance frequency of the resonator out of the frequency sweeping signals received by the first coil 11a with the second coil 11b via the ground coil 15, when the pickup coil is electromagnetically connected with the ground coil 15. In the signal detection unit 13, the signal obtained by the second coil 11b of the pickup coil 11 is subjected to Fourier transform in a time cycle equal to the specific time cycle, and the detection treatment of the ground coil 15 is performed on the basis of the signal after the Fourier transform.

Description

  An embodiment of the present invention relates to an on-train apparatus for automatic train stop (ATS).

  Conventionally, in an automatic train stop (Automatic Train Stop: ATS) on-board device, when the ground unit and the vehicle unit are combined, it is detected that the oscillation frequency always changes to the resonance frequency set on the ground unit. There is known a frequency dividing method using a so-called frequency pull-in phenomenon. However, since the variable frequency ATS on-board device uses a feedback oscillation circuit, it is necessary to design the circuit so as to satisfy the oscillation conditions at all times and at the time of frequency variation. An ATS device has been proposed that does not use a feedback oscillation circuit and does not need to constantly vary the oscillation frequency because it is a mechanism that creates an unstable oscillation state due to the influence of metal or the like.

In one proposal (Prior Art 1), a frequency signal corresponding to each of the resonance frequencies f _{1 to} f _n used in the ground unit is generated by an oscillator, and a signal obtained by adding the signals from the primary coil of the vehicle upper unit. When the vehicle upper element is electromagnetically coupled to the ground element, the fact that one of the frequency signals included in the sum signal is tuned to the resonance frequency of the ground element increases the signal level of that frequency. Is realized.

On the other hand, another proposal (Prior Art 2) is realized by generating a spread spectrum signal including f _{1 to} f _n and outputting the signal from the primary coil of the vehicle armature. In this way, a signal having a spectrum including all resonance frequencies that can be used in the ground unit is output from the primary coil of the vehicle so as to resonate (tune) when electromagnetically coupled to the ground unit. Thus, it is possible to realize an ATS on-board device that does not use a feedback oscillation circuit.

JP-A-8-58588 JP 2005-229789

  However, the above-described conventional automatic train control on-board device that does not use the feedback oscillation circuit has the following problems.

  Due to aging deterioration and manufacturing errors, fluctuation (shift) occurs in the resonance frequency of the ground element. Therefore, in the case of the method of transmitting a signal corresponding to the resonance frequency of the ground element from the vehicle upper element as in the conventional technique 1, when a deviation occurs in the resonance frequency of the ground element with respect to the transmission signal from the vehicle upper element, The magnitude of the signal level induced in the vehicle upper coil is reduced. The greater the sharpness (Q value) of the resonance of the ground element, the greater the effect. In some cases, it is conceivable that the reception signal level at the secondary coil of the vehicle is not induced even though the vehicle is passed over the ground. The resonance frequency detection accuracy in the on-board device greatly affects the signal level induced by the vehicle upper secondary coil. Therefore, when the above-mentioned conventional method has a deviation in the ground child resonance frequency, the resonance frequency detection accuracy is low. There was a problem of lowering. In general, to improve detection accuracy, it is possible to use the Q value calculated using the signal received by the vehicle upper secondary coil for the determination. Since only a sine wave (single frequency) is added, it is impossible to calculate the Q value using the received signal at the vehicle upper secondary coil.

On the other hand, in the case of the above-described conventional technique 2 using a spread spectrum signal, pseudo noise is transmitted, so the amplitude distribution of the transmission spectrum follows a Rayleigh distribution instead of a uniform distribution. Of course, since the reception spectrum amplitude at the secondary coil of the vehicle is induced based on the transmission spectrum amplitude, when the ground unit and the vehicle unit are electromagnetically coupled, the resonance frequency of the ground unit is not necessarily the peak frequency. The resonance frequency may be erroneously detected. Further, since it has a frequency bandwidth including at least f _{1 to} f _n , the Q value can be calculated, but the accuracy of the obtained calculated Q value is low.

  As described above, in the conventional method, when the on-board device detects the resonance frequency of the ground unit, there is a problem that the detection accuracy of the resonance frequency is lowered.

  An object of one aspect of the present invention is to provide a train-controlled on-board device that does not use a feedback oscillation circuit and that can prevent erroneous detection of the resonance frequency of the ground element and improve the accuracy of detection of the resonance frequency. To do.

  A train-controlled on-board apparatus as an embodiment of the present invention is a train-controlled on-board apparatus that performs train control using a ground element including a resonator, and includes a signal generation unit, a vehicle upper element, a signal detection unit, Is provided.

  The signal generation unit generates a frequency sweep signal by sweeping the frequency within an allowable variation range including a resonance frequency of the resonator at a specific time period.

  The vehicle upper element has a first coil that receives the frequency sweep signal, and a second coil that obtains a signal by electromagnetic coupling with the first coil. Of the received frequency sweep signal, a signal component corresponding to the resonance frequency of the resonator is obtained by the second coil via the ground element.

  The signal detection unit Fourier-transforms a signal obtained by the second coil of the vehicle upper unit at a time period equal to the specific time period, and detects the ground unit based on the signal after the Fourier transform. Process.

The block diagram which shows the structural example of the train control vehicle upper apparatus of embodiment of this invention. The figure which shows the example of the spectrum waveform applied to a vehicle upper primary coil. The block diagram which shows the other structural example of a signal generation part. The figure which shows the example of the spectrum waveform output by a FFT calculating part. The figure which shows the example of the FFT output result by the difference in the relationship between a frequency sweep period and an FFT period.

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

(First embodiment)
FIG. 1 is a block diagram illustrating a configuration example of a train control on-vehicle apparatus according to an embodiment of the present invention.

The train control on-board apparatus in FIG. 1 includes at least an on-board element 11, a signal generation unit 12, a signal detection unit 13, and a control unit. The vehicle upper element 11 is electromagnetically coupled to a ground element 15 installed on the ground as the train travels. The ground element 15 is composed of a resonator (in the example of FIG. 1, an example of an LC resonator in which a coil and a capacitor are connected in series is shown, but the ground element is not limited to this), and one resonance frequency have. In the present embodiment, the ground element 15 has any _one of frequencies f _{1 to} f _n as a resonance frequency (for example, any one of 103 kHz, 108 kHz, 123 kHz, 130 kHz, etc.).

  Here, the train is a vehicle that travels on rails such as railroad tracks, and examples thereof include trains, bullet trains, monorails, and linear motor cars. The train control onboard apparatus of this embodiment is mounted on this train. The above-mentioned ground element 15 is provided at a predetermined position of the rail. The place where the ground element 15 is provided may be one place or a plurality of places. In this embodiment, the case where a ground element is provided in a plurality of locations is shown.

  The signal generation unit 12 generates a frequency sweep signal by sweeping the frequency in each of the allowable variation ranges including the resonance frequency of each ground element at a specific time period. The signal generator 12 adds the generated frequency sweep signals, and D / A converts and amplifies the added signal.

  The vehicle upper arm 11 includes a primary coil 11a and a secondary coil 11b. The primary coil 11a and the secondary coil 11b are arranged so that they can be electromagnetically coupled. For example, the primary coil 11a and the secondary coil 11b are arranged so as to be electromagnetically loosely coupled to each other. The signal generated by the signal generator 12 is applied to the primary coil 11a. On the other hand, the secondary coil 11b inputs a signal obtained by electromagnetic coupling with at least the former of the primary coil 11a and the ground element 15 to the signal detection unit 13.

  When the vehicle upper arm 11 (the primary coil 11a and the secondary coil 11b) is not electromagnetically coupled to the ground element 15, that is, when the secondary coil 11b is coupled only to the primary coil 11a, the secondary coil 11b. Receives all frequency bands of the frequency sweep signal received by the primary coil 11a by coupling with the primary coil 11a.

  On the other hand, when the vehicle upper element 11 is electromagnetically coupled to the ground element 15, that is, when the coils 11a and 11b of the vehicle upper element 11 are electromagnetically coupled to the coil of the ground element 15, the resonance frequency of the ground element 15 and its Regarding the signal components in the vicinity, signal reception via the ground element 15 (reception of the resonance signal in the ground element 15) becomes dominant due to the resonator coupling of the coil 11a, the ground element 15 and the coil 11b, and other frequencies. As for the signal component, signal reception by electromagnetic coupling with the primary coil 11a is dominant. As a result, when coupled to the ground unit 15, the amplitude level of the signal component near the resonance frequency of the signal received by the secondary coil 11b greatly increases due to the resonance phenomenon in the resonator as compared with the uncoupled state.

  The signal detection unit 13 converts the signal received by the secondary coil into a frequency domain signal by Fourier transform such as FFT, and performs ground element detection processing. In the detection process, the presence of the ground element (passage on the ground element) is detected based on the converted signal, and the detected resonance frequency of the ground element is detected. The signal detection unit 13 outputs the detected resonance frequency to the control unit 14.

  The control unit 14 performs control processing determined for each frequency, such as creation of a speed check pattern, according to the resonance frequency notified from the signal detection unit 13. The speed check is to check whether the speed of the train is within an allowable speed range. If it is out of the speed range, the control unit 14 can also control the speed of the train so that the speed is within the range.

Hereinafter, the signal generation unit 12 will be described in detail. The signal generation unit 12 includes at least a frequency sweep signal generation unit 121 (121 _{1 to} 121 _n ), an addition circuit 122, a D / A converter 123, and a power amplifier 124.

In the frequency sweep signal generator 121 (121 _{1 to} 121 _n ), each resonance frequency f _{1 to} f _n that can be used in the ground unit 15 is set as a center frequency, and tolerance for deviation of resonance frequency caused by aging degradation or manufacturing error is allowed. In the variation range (± XkHz), a frequency swept signal is generated for each predetermined fixed period. That is, a signal is generated while the frequency is swept within the range within one cycle period, and this is performed at regular intervals. In general, the allowable variation range with respect to the deviation of the resonance frequency at the ground is defined as a safety reference level. The period for performing the frequency sweep will be described later.

The signals generated by the frequency sweep signal generators 121 _{1 to} 121 _n are added by the adder circuit 122 and converted to an analog signal by the D / A converter 123. The converted analog signal is amplified by the power amplifier 124 and output to the primary coil 11a of the vehicle upper arm 11.

In the above description, the allowable variation range for each resonance frequency is the same (± X kHz). When a different range of deviation (± X ₁ kHz to ± X _n kHz) is allowed for each resonance frequency, the frequency sweep signals generated by the frequency sweep signal generators 121 _{1 to} 121 _n are ( This is a signal obtained by frequency sweeping the spectral range from f _i -Xi) kHz to (f _i + Xi) kHz [i = 1 to n] within one period. Therefore, if there are four types of resonance frequencies (103 kHz, 108 kHz, 123 kHz, 130 kHz) used in the ground unit 15 and the allowable variation range for each resonance frequency is ± 2 kHz in common, the spectrum shown in FIG. This signal is output to the primary coil 11a of the vehicle upper arm 11 (frequency sweep cycle Tms).

Here, the frequency sweep signal generation method in each of the frequency sweep signal generation units 121 _{1 to} 121 _n may be realized by any method.

  For example, the waveform data of the frequency sweep signal centered on each resonance frequency is stored in advance in a ROM (not shown), and stored in the ROM by specifying the address address of the ROM where each frequency sweep signal is stored. This can be realized by reading out each frequency sweep signal and adding the waveform data read out from each address address.

  Alternatively, a method in which a signal to which each frequency sweep signal has been added in advance is stored in the ROM as waveform data and the waveform data is read from the stored address address of the ROM may be used. In this case, since each resonance frequency sweep signal is already added as waveform data, the adding circuit 122 is not necessary, and it is only necessary to read the waveform data from the ROM.

Alternatively, as shown in FIG. 3, V / F (Voltage / Frequency) converters 125 _{1 to} 125 _n are configured for each frequency sweep signal generation unit, and output from the D / A converter 123 by the shift register 126. After controlling the voltage value to linearly increase, each V / F converter 125 _{1 to} 125 _n converts the voltage output from the D / A converter 123 into a frequency signal proportional to the voltage, respectively ( A method of generating a signal obtained by frequency sweeping the spectrum range from (f _i −Xi) kHz to (f _i + Xi) kHz [i = 1 to n] may be used.

  Next, the signal detection unit 13 will be described in detail. The signal detection unit 13 includes at least an A / D converter 131, an FFT (Fast Fourier Transform) calculation unit 132 as an embodiment of a Fourier transform unit, and a resonance frequency detection unit 133. In this embodiment, an FFT calculation unit is used as a Fourier transform unit. However, if a time domain signal can be converted to a frequency domain signal (frequency spectrum), the FFT transform unit is not limited to the FFT, and how to use the Fourier transform. You may use a different method.

  The signal detection unit 13 converts the received signal input through the secondary coil 11b of the vehicle upper arm 11 into a digital signal by the A / D converter 131, and then performs frequency analysis in the FFT calculation unit 132 to perform frequency analysis. Convert to a signal.

  The resonance frequency detection unit 133 analyzes the frequency domain signal obtained by the FFT calculation unit 132 based on the threshold value, and detects that the vehicle upper arm 11 is electromagnetically coupled to the ground child 15 and determines that it has been detected. The resonance frequency of the ground unit 15 is specified.

Since, for purposes of explanation, the ground coil 15 will be described in the case where a f ₃ of the frequency f ₁ ~f _n as the resonant frequency. When the vehicle upper element 11 is not in the vicinity of the ground element 15, that is, when the vehicle upper element 11 and the ground element 15 are not electromagnetically coupled, the output spectrum of the FFT operation unit 132 as shown in FIG. Has a spectrum waveform in which the signal applied to the primary coil of the vehicle upper core 11 is only attenuated (the attenuation signal of the signal input to the primary coil is given to the secondary coil). That is, the spectrum of each sweep signal centered on each resonance frequency f _{1 to} f _n is a constant voltage.

In this state, when the vehicle upper element 11 approaches the ground element 15 (for example, when passing over the ground element 15), the vehicle upper element 11 and the ground element 15 are electromagnetically coupled and the ground element 15 resonates. resonance frequency f ₃ near the reception level rises with the child 15. Therefore, the spectrum waveform is as shown in FIG. Therefore, if beforehand monitors the signal level of each frequency of the output spectrum of the FFT computing unit 132 in the resonance frequency detection unit 133, the voltage level of the peak frequency (the voltage level in this case f ₃₎ is not electromagnetically coupled In comparison, it is determined that the vehicle upper element 11 is electromagnetically coupled to the ground element 15 by detecting that the voltage has risen above a predetermined level or by detecting that the voltage level has exceeded the threshold value.

  If it is determined that it has been detected, the peak frequency is specified as the resonance frequency of the ground unit 15. In consideration of the occurrence of a deviation in the resonance frequency, even if the peak frequency does not match any resonance frequency, the resonance frequency detection unit 133 treats the resonance frequency as the resonance frequency if the peak frequency is within the allowable fluctuation range. Shall. Conversely, no matter how large the increase in the reception voltage level is, if the peak frequency is outside the fluctuation range, it is not an increase in the reception level due to electromagnetic coupling with the ground unit 15, but an impulse noise type. It can also be handled as an increase in reception level due to the input of external noise, and can operate stably without erroneous detection of external noise.

In the embodiment of the present invention, the signal transmitted from the signal generation unit 12 is a signal obtained by adding frequency sweep signals with the resonance frequencies f _{1 to} f _n as the center frequencies. The Q value can be calculated using the output signal of the calculation unit 132. The Q value of the resonance frequency in the ground unit 15 is subjected to safety inspection and inspection so as to maintain a value above a certain level. Therefore, the resonance frequency detection unit 133 calculates the Q value at the peak frequency specified by using the FFT output result, and further determines a condition for determining that the ground element 15 is electromagnetically coupled only when the calculated Q value exceeds a certain threshold value. By adding, it becomes possible to further prevent ground element erroneous detection determination due to noise or the like. The Q value is calculated by j1 / (j3-j2) where j1 is the peak frequency of the resonance signal and j2 and j3 (j2 <j3) are the frequencies on both sides where the amplitude is 1/2 of the peak frequency. Can.

  Here, the FFT processing performed by the FFT calculation unit 132 will be described.

To correctly identify which without determining the resonant frequency of the ground unit 15 at the resonance frequency detection unit 133 erroneously neighboring resonant frequency, the frequency resolution to achieve at least FFT, f ₁ ~f _n lowest frequency interval or fineness of It is essential to keep it. For example, when the resonant frequency is 103kHz, 108kHz, 123kHz, 130kHz, the minimum frequency interval is 5kHz between 103kHz and 108kHz, so it is necessary to have FFT processing with a fine frequency resolution of at least 5kHz or more. . In this case, if an FFT process with only a frequency resolution coarser than 5 kHz is performed, it cannot be distinguished whether the peak frequency obtained from the FFT output is caused by the resonant frequency 103 kHz or 108 kHz. This is because it may occur that it is impossible to specify whether the frequency is the resonance frequency.

  Setting the FFT frequency resolution to be finer than the minimum resonance frequency interval is the minimum necessary lower limit value.For example, if the peak frequency is within the allowable fluctuation range as described above, Since it is necessary to determine whether or not the peak frequency is within the allowable fluctuation range, at least the FFT frequency resolution needs to be finer than the maximum value of the allowable fluctuation range. Since the allowable fluctuation range is always a small value compared to the resonance frequency interval, the maximum allowable fluctuation value of the frequency deviation is the lower limit of the FFT frequency resolution in this case.

  Of course, from the viewpoint of peak frequency identification accuracy and Q value calculation accuracy, it is desirable to output the FFT with the finest possible frequency resolution while setting one of the two FFT frequency resolutions as the lower limit. . In order to increase the frequency resolution in the FFT, it is necessary to reduce the time resolution required for the FFT (increase the FFT period). That is, in order to perform one FFT process, signal data for a longer time is required.

On the other hand, it is desired that the FFT operation unit 132 outputs a plurality of FFT results while the vehicle upper element 11 is electromagnetically coupled to the ground element 15. In other words, this means that the time resolution required for the FFT is increased (the FFT cycle is shortened). It is also conceivable that instantaneous impulse noise external noise having a frequency equal to the resonance frequency f _{1 to} f _n is input. If the FFT time resolution is large (the FFT cycle is long), the FFT output results indicate that there is a peak frequency due to instantaneous impulsive noise input, or that there is actually a peak frequency due to electromagnetic coupling with the ground unit 15. There is a possibility that it cannot be judged whether it is doing. Therefore, by performing FFT processing with the time resolution (FFT cycle) that can output the FFT results multiple times (N times here) within the shortest coupling time (described later) when passing over one ground element The resonance frequency detection unit 133 can make the following determination.

  In other words, if a peak frequency having a certain Q value and a certain voltage level or more can be detected continuously N times or more, it is determined that it is electromagnetically coupled to the ground element 15, and if it is less than N times, instantaneous noise is detected. It is determined that the level has increased due to In other words, this means that when electromagnetic coupling with the ground element 15 is used, the shortest coupling time always uses the continuous reception of a signal having a peak frequency above a certain level at a certain resonance frequency. By performing the FFT output multiple times (N times), the ground element coupling and the ground element non-coupling (impulsive noise) are distinguished from the N times of output results, and further prevention of false detection of ground elements is possible.

  The shortest coupling time between the vehicle upper element 11 and the ground element 15 is a time uniquely determined from the minimum operating distance between the vehicle upper element 11 and the ground element 15 and the maximum train speed. The minimum response distance is the minimum value of the connectable distance between the vehicle upper and the ground along the track of the vehicle upper. For example, if the minimum working distance is 300mm and the train speed is up to 140km / h, the shortest coupling time is about 8ms. Therefore, it is necessary to perform the FFT processing (determining the sampling rate, the number of FFT points, etc.) so that the FFT cycle is 8 / N ms. In this case, the FFT frequency resolution is N / 8 kHz. The number of FFTs output within the shortest coupling time is determined by the type of noise that is expected to occur, the shortest coupling time, the circuit scale, the frequency band in which the resonance frequency is used, and the like.

  As described above, the FFT calculation unit 132 in the embodiment of the present invention is finer than the minimum frequency interval (or maximum allowable frequency variation value) of the resonance frequency, and N / shortest coupling time (where N is predetermined). FFT processing that satisfies the frequency resolution within the range of roughness less than or equal to 2 natural numbers). In addition, as the FFT period, a time signal with a length of 1 / resonance frequency minimum frequency interval (or 1 / frequency maximum allowable variation) and a short time range of shortest coupling time / N or less is used. This is equivalent to implementing FFT.

  Next, a cycle for performing frequency sweep in the signal generation unit 12 will be described.

  As described above, the frequency sweep signal generation unit 121 generates a signal obtained by frequency sweeping the permissible variation range with respect to the shift of the resonance frequency around each resonance frequency at every predetermined fixed period.

  At this time, the time period for each frequency sweep is a time period equal to the FFT period of the FFT processing performed by the FFT operation unit 132. Here, the equal time period does not necessarily indicate a completely coincident value but includes a design error and the like, for example, a deviation within 10% of the time period is allowed.

  In the embodiment of the present invention, as described above, as a constraint of the FFT period, the length is 1 / resonance frequency minimum frequency interval (or 1 / frequency maximum permissible fluctuation value) or more, and shortest coupling time / N or less short Since it is set in the time range, the time period of the frequency sweep signal in the signal generation unit 12 is naturally, and the length is 1 / minimum minimum frequency interval (or 1 / frequency maximum allowable fluctuation value), and The short time range is less than the shortest coupling time / N.

  As an example, assuming that the allowable fluctuation value of the resonance frequency is ± 2 kHz, the shortest coupling time is 8 ms, and the FFT output frequency N is 4 times within the shortest coupling time, if the FFT cycle and the frequency sweep cycle are 2 ms, the above conditions Fits in range. Therefore, the frequency sweep signal generation unit 121 sweeps a range of ± 2 kHz around each resonance frequency, for example, 103 kHz, that is, a frequency range of 101 kHz to 105 kHz every 2 ms.

  The reason and effect of making the FFT period equal to each frequency sweep period will be described. FIG. 5 shows an example of the FFT output result due to the difference in the relationship between the frequency sweep period and the FFT period. When the FFT period is equal to the frequency sweep period (graph G1), when the frequency sweep period is shorter than the FFT period (1/2 times) (graph G2), when the frequency sweep period is longer than the FFT period (2 times) ) (Graph G3) is an example of the output result.

  If the frequency sweep period is shorter than the FFT period, that is, if the FFT period is longer than the frequency sweep period, the result of multiple frequency sweeps for one FFT output result is included, as shown in graph G2 in Fig. 5. Thus, the FFT output result is such that a specific frequency is periodically lost. This is because the frequency sweep cycle in the signal generator 12 fluctuates faster than the time resolution that can be achieved by the FFT processing performed by the FFT calculator 132, and as a result, a fast frequency sweep is expressed as the FFT output spectrum. An FFT output result that cannot be obtained is obtained. If the resonance frequency is specified or the Q value is calculated using the FFT output result, the peak frequency is specified accurately when the resonance frequency of the ground unit 15 is missing in the FFT output result. Affects. Similarly, the accuracy of Q value calculation is also lowered. As described above, when the frequency sweep period is shorter than the FFT period, a frequency sweep that is fast in terms of resolution cannot be expressed as an FFT output result, which affects the accuracy of peak frequency specification and Q value calculation. Naturally, the shorter the frequency sweep period compared to the FFT period (the faster the speed sweep), the more the FFT output result is affected, and the accuracy of peak frequency specification and Q value calculation becomes worse.

  On the other hand, when the frequency sweep period is longer than the FFT period, that is, when the FFT period is shorter than the frequency sweep period, the result of one frequency sweep is obtained through a plurality of FFT output results. This is not necessarily the result of frequency sweeping within a range that includes the resonance frequency. For example, when the frequency sweep period is twice as long as the FFT period, the FFT output result once every two times becomes a spectrum reflecting the result in the frequency sweep range not including the resonance frequency. In the case of FIG. 5, as shown in the graph G3, the frequency sweep result is output at a timing in a range not including 80 kHz with respect to the ground resonance frequency of 80 kHz. Therefore, although a peak above a certain voltage level is obtained, the obtained peak frequency is the output result in the frequency swept range at the FFT timing, so in this case the peak is at a frequency lower than the actual resonance frequency of 80 kHz. The frequency is obtained. This means that the peak frequency obtained at each FFT output can be obtained differently depending on the frequency sweep range each time. Further, depending on the Q value of the resonance frequency of the ground unit, it is conceivable that the reception signal level is not sufficiently induced in the frequency sweep FFT output at the timing in the range not including the resonance frequency.

  In this way, when the frequency sweep period is longer than the FFT period and the FFT output result for the frequency sweep signal in the range not including the ground element resonance frequency is obtained, the received signal level is sufficiently induced depending on the Q value of the ground element. Even if an induction exceeding a certain voltage level is obtained, the voltage level is lower than the peak frequency voltage level obtained from the FFT output result in the frequency sweep including the resonance frequency, and depends on the frequency sweep range. Therefore, the value of the peak frequency will be different each time. The resonance frequency detection accuracy is greatly related to the signal level induced by the secondary coil 11b of the vehicle upper arm 11, so that the reduction of the induced voltage is not a little, and it has an adverse effect on the ground child detection accuracy and the resonance frequency detection accuracy. Become. If the received signal level is not sufficiently induced, the FFT output result having a peak frequency equal to or higher than a certain voltage level is repeated N times even though the vehicle upper 11 is electromagnetically coupled to the ground 15. As described above, the method of determining that the electromagnetic coupling with the ground element 15 is made only when it can be detected continuously N times or more cannot be used. Of course, the longer the frequency sweep period compared to the FFT period (the slower the slower), the greater these effects.

  As described above, whether the frequency sweep period is long or short with respect to the FFT period, as a result, the ground element detection accuracy and the resonance frequency specifying accuracy are affected. Therefore, by setting the FFT period and the frequency sweep frequency period to be equal, the FFT output result shown in the graph G1 is obtained, and erroneous detection of the resonance frequency of the ground element can be prevented and frequency detection accuracy can be improved.

  For the above reasons, it is desirable to set the FFT period and frequency sweep frequency period to be equal, but setting the frequency sweep period to be greater than the FFT period can at least solve the problem when the frequency sweep period is shorter than the FFT period. Therefore, a method of setting the frequency sweep period to be equal to or greater than the FFT period may be used. Conversely, by setting the frequency sweep cycle shorter than the FFT cycle, the problem that the frequency sweep cycle is longer than the FFT cycle can be solved at least, so the frequency sweep cycle is set shorter than the FFT cycle. It may be a method.

  Here, when the frequency sweep signal generation unit 121 generates a frequency sweep signal centered on each resonance frequency, it is generally considered that the phase of the signal across the frequency sweep cycle becomes discontinuous. .

  For example, if a frequency sweep is performed from 101kHz to 105kHz in a certain cycle centered on a frequency of 103kHz, after the frequency shifts to 105kHz, when the frequency sweep is restarted from 101kHz in the next cycle, the frequency is switched from 105kHz to 101kHz. In general, the phase becomes discontinuous due to the relationship of the oscillator or the like at the same timing.

  Assuming that the signal generation unit 12 and the signal detection unit 13 operate asynchronously, even if the FFT cycle and the frequency sweep cycle are the same cycle, the FFT processing performed by the FFT calculation unit 132 in the signal detection unit 13 In most cases, the calculation is performed by using one period of the frequency sweep signal across the period. Therefore, when performing the FFT calculation, one period of phase discontinuous frequency sweep signal (for example, 102 kHz → 105 kHz, 101 kHz → 102 kHz) is used, and the resonance frequency detector 133 uses the phase continuous signal to perform the FFT. Compared with the case where the output result is used, the detection accuracy tends to deteriorate. For this reason, it is desirable to generate the frequency sweep signal so that the phase of the signal when the frequency sweep cycle is straddled is continuous. Specifically, when straddling the frequency sweep cycle, a method of holding the phase at the end of the frequency sweep and using it as the initial phase of the next frequency sweep cycle is conceivable.

  For example, when frequency sweeping from 101kHz to 105kHz, if the phase at 105kHz is α [radian], the initial phase at the next frequency sweep cycle start frequency of 101kHz is α [radian] and the sweep cycle is started. Can be generated as a phase-continuous signal.

  In addition, as the frequency sweep direction, the next cycle after sweeping from 101 kHz to 105 kHz can be realized as a continuous phase signal even when the sweep cycle is crossed by sweeping from 105 kHz to 105 kHz as the sweep start frequency. is there. That is, in the allowable variation range, the frequency sweep from the first frequency to the second frequency and the frequency sweep from the second frequency to the first frequency are alternately repeated at a specific time period. The first frequency is, for example, the minimum value or the maximum value of the allowable variation range, and the second frequency is the maximum value or the minimum value.

  Alternatively, even if the phase of the signal across the frequency sweep cycle is discontinuous, it is possible to synchronize the frequency sweep cycle start timing with the FFT start timing by synchronizing the signal generation unit 12 and the signal detection unit 13. It becomes possible. For this reason, in this case, FFT calculation is possible using a signal that does not straddle the frequency sweep cycle, so that the same FFT output result as that obtained when the signal phase across the frequency sweep cycle is continuous is obtained. However, when synchronizing the signal generation unit 12 and the signal detection unit 13, although not shown in FIG. 1, there is no input of any synchronization signal for synchronization from the signal generation unit 12 to the signal detection unit 13. Necessary.

  As described above, in the embodiment of the present invention, when the frequency sweep signal generation unit 121 generates the frequency sweep signal centered on each resonance frequency, the generation control is performed so that the phase when the sweep period is straddled is continuous, or By synchronizing the signal generation unit 12 and the signal detection unit 13, the FFT calculation in the FFT calculation unit 132 can use a signal having a phase continuity, thereby preventing erroneous detection of the resonance frequency of the ground element and frequency detection accuracy. It is possible to realize improvement of the above.

  As described above, in the embodiment of the present invention, as a transmission signal to be output to the vehicle upper primary coil, an allowable fluctuation range of the resonance frequency centered on each resonance frequency used in the ground child is set to a specific time period. When the vehicle upper is electromagnetically coupled to the ground child by using the signals obtained by adding the frequency swept signals at, even if there is a deviation in the ground child resonance frequency, the vehicle upper secondary coil Since the signal level induced in 11b is not reduced, detection is possible without affecting the ground element detection accuracy and the resonance frequency detection accuracy. Compared to the case of using a pseudo-noise signal by spread spectrum as a transmission signal, it is possible to transmit a signal with a stable and constant voltage level in each frequency spectrum. The detection accuracy and the resonance frequency detection accuracy can be improved.

  Furthermore, considering the output result in the FFT calculation used for ground detection and resonance frequency detection, the FFT output result is set by setting the sweep period when generating the frequency sweep signal equal to the time period of the FFT calculation. By using this, it is possible to further improve the accuracy at the time of carrying out ground element detection accuracy and resonance frequency detection.

  In addition, as the time period, the length is at least the minimum frequency interval of 1 / resonance frequency (or 1 / frequency maximum allowable fluctuation value) and the shortest coupling time / N (N is a natural number of 2 or more) or less. By setting the range, the FFT output result enables multiple FFT outputs per ground unit coupling while maintaining frequency resolution that does not falsely detect adjacent resonant frequencies, and uses multiple consecutive FFT output results Thus, erroneous detection of the ground element due to instantaneous impulsive noise or the like can be further prevented.

  In addition, because the creation control is performed so that the phase when the frequency sweep cycle crosses is continuous, or the signal generation unit 12 and the signal detection unit 13 are synchronized, it is possible to use a signal in which the FFT operation is phase continuous. Similarly, it is possible to further improve the accuracy of detecting the ground element and the resonance frequency using the FFT output result.

  Note that the present invention is not limited to the above-described embodiment as it is, and can be embodied by modifying the constituent elements without departing from the scope of the invention in the implementation stage. In addition, various inventions can be formed by appropriately combining a plurality of components disclosed in the embodiment. For example, some components may be deleted from all the components shown in the embodiment. Furthermore, constituent elements over different embodiments may be appropriately combined.

Claims (12)

A train control on-vehicle device that performs train control using a ground element including a resonator,
A signal generation unit that generates a frequency sweep signal by sweeping a frequency within an allowable variation range including a resonance frequency of the resonator at a specific time period;
A first coil that receives the frequency sweep signal; and a second coil that obtains a signal by electromagnetic coupling with the first coil, and the frequency sweep signal received by the first coil when electromagnetically coupled to the ground unit. A signal component corresponding to the resonance frequency of the resonator is obtained by the second coil via the ground element,
A signal detection unit that performs Fourier transform on the signal obtained by the second coil of the vehicle upper element at a time period equal to the specific time period, and performs detection processing of the ground element based on the signal after Fourier transform When,
Train control on-vehicle equipment with Train control using a plurality of ground elements each having a resonator with a different resonance frequency,
The signal generation unit generates the frequency sweep signal for each resonance frequency, adds each generated frequency sweep signal,
The first coil of the upper arm receives the added frequency sweep signal;
2. The train control on-vehicle apparatus according to claim 1, wherein The time period of the Fourier transform is
1 / (the shortest resonance frequency interval among the intervals between the resonance frequencies) or more, and (the shortest time in which the vehicle element is electromagnetically coupled to the ground element) / N (N is a natural number of 2 or more) The train control vehicle on-board device according to claim 2, characterized in that: The time period of the Fourier transform is
1 / (the maximum value of the allowable fluctuation range of each resonance frequency) or more,
3. The train-controlled on-board device according to claim 2, wherein the on-train device is less than (the shortest time in which the on-board child is electromagnetically coupled to the ground unit) / N (N is a natural number of 2 or more). When generating the sweep signal at the specific time period, the signal generation unit uses the final phase of the sweep signal generated at the previous time period as the initial phase of the sweep signal generated at the next time period. The train control vehicle on-board device according to any one of claims 1 to 4. The signal generation unit alternately repeats a frequency sweep from the first frequency to the second frequency and a frequency sweep from the second frequency to the first frequency in the allowable variation range at the specific time period. The train control vehicle on-board device according to any one of claims 1 to 4. The first frequency is a minimum frequency or a maximum frequency included in the allowable variation range,
The train control on-vehicle apparatus according to claim 6, wherein the second frequency is a maximum frequency or a minimum frequency included in the allowable variation range. 2. The frequency sweep cycle start timing in the signal generation unit and the Fourier transform cycle start timing in the Fourier transform unit are matched by synchronizing the signal generation unit and the signal detection unit. The train control on-vehicle device according to any one of 4. A train-controlled on-board device that performs train control using a ground unit,
A signal generation unit that generates a frequency sweep signal by sweeping a frequency within an allowable variation range including a resonance frequency of the ground element at a specific time period;
A first coil that receives the frequency sweep signal; and a second coil that obtains a signal by electromagnetic coupling with the first coil, and the frequency sweep signal received by the first coil when electromagnetically coupled to the ground unit. A signal component corresponding to the resonance frequency of the resonator is obtained by the second coil via the ground element,
A signal detection unit that performs Fourier transform on a signal obtained by the second coil of the vehicle upper unit at a time period larger than the specific time period, and performs detection processing of the ground unit based on the signal after Fourier transform When,
Train control on-vehicle equipment with Train control using a plurality of the above-mentioned ground elements having a plurality of different resonance frequencies,
The signal generator generates the frequency sweep signal for each resonance frequency of the plurality of ground elements, adds the generated frequency sweep signals, and gives the added frequency sweep signal to the vehicle upper element.
10. The train control on-vehicle apparatus according to claim 9, wherein A train-controlled on-board device that performs train control using a ground unit composed of a resonator,
A signal generation unit that generates a frequency sweep signal by sweeping a frequency within an allowable variation range including a resonance frequency of the ground element at a specific time period;
A first coil that receives the frequency sweep signal; and a second coil that obtains a signal by electromagnetic coupling with the first coil, and the frequency sweep signal received by the first coil when electromagnetically coupled to the ground unit. A signal component corresponding to the resonance frequency of the resonator is obtained by the second coil via the ground element,
A signal detection unit that Fourier-transforms the signal obtained by the second coil of the vehicle upper unit at a time period smaller than the specific time period, and performs detection processing of the ground unit based on the signal after Fourier transform When,
Train control on-vehicle equipment with Train control using a plurality of the above-mentioned ground elements having a plurality of different resonance frequencies,
The signal generator generates the frequency sweep signal for each resonance frequency of the plurality of ground elements, adds the generated frequency sweep signals, and gives the added frequency sweep signal to the primary coil.
12. The train control on-vehicle apparatus according to claim 11, wherein

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