JP2006300702A - Revolution speed detector and rotating flying object - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To accurately detect a revolution speed of a rotating flying object without being affected by disturbance. <P>SOLUTION: This revolution speed detector adopts a means provided with: an acceleration detecting means for detecting a centrifugal acceleration generated by rotation of a rotor and a gravity acceleration, and for outputting an acceleration detection signal in response to a composed acceleration of the centrifugal acceleration and the gravity acceleration; and a signal processing means for detecting a revolution speed of the rotor, on the basis a fluctuation period of the acceleration detection signal. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a rotation speed detection device and a rotating flying object.

  Conventionally, as one of the methods for detecting the number of rotations of a rotating projectile, a light receiving sensor is provided on the surface of the rotating projecting object to detect sunlight, and the fluctuation period of an electric signal according to the amount of received sunlight is detected. There is a technique for detecting the number of rotations of the rotating projectile based on the above.

  However, in the method using the light receiving sensor in the above prior art, the amount of light detected by the light receiving sensor is affected, for example, the amount of sunlight fluctuates depending on the flight time of the rotating projectile body, or it is affected by reflected light generated by the sunlight reflected on the ground. There is a problem that the rotational speed detection accuracy is lowered due to instability.

 The present invention has been made in view of such circumstances, and an object thereof is to accurately detect the rotational speed of a rotating projectile body without being affected by disturbance as in the prior art.

 In order to solve the above-mentioned problem, in the present invention, as a first solving means related to the rotational speed detection device, the centrifugal acceleration and the gravitational acceleration are detected while detecting the centrifugal acceleration and the gravitational acceleration caused by the rotation of the rotating body. An acceleration detecting means for outputting an acceleration detection signal corresponding to the combined acceleration and a signal processing means for detecting the number of rotations of the rotating body based on the fluctuation period of the acceleration detection signal are employed.

 Further, as a second solving means relating to the rotation speed detecting device, in the first solving means, two acceleration detecting means are provided at positions symmetrical to the rotation center of the rotating body, and the signal processing means is The means for detecting the number of rotations of the rotating body based on the fluctuation cycle of the difference between the acceleration detection signals respectively output from the two acceleration detection means is employed.

On the other hand, as a solving means related to the rotating flying object, a rotating flying object that flies while rotating toward the target, the distance measuring means for measuring the distance to the target, and the rotational speed detecting device The first or second solving means, the elevation angle φ of the rotating projectile with respect to the ground surface, the gravitational acceleration g, the maximum value of the acceleration detection signal (maximum value of combined acceleration A1 _max ), and the minimum value (minimum value of combined acceleration A1) _min ) is calculated by the following relational expression (5), and the rotation angle is calculated by the following relational expression (6) regarding the elevation angle φ, the distance L to the target, and the height H of the rotating projectile from the ground surface. An arithmetic processing means for calculating the height H of the flying object from the ground surface is used.

  According to the present invention, the centrifugal acceleration and the gravitational acceleration generated by the rotation of the rotating flying object are detected, and the number of rotations is detected based on the fluctuation period of the acceleration detection signal corresponding to the combined acceleration. Compared with a method using such a light receiving sensor, the rotational speed can be accurately detected without being affected by disturbance.

  Further, the elevation angle φ with respect to the ground surface of the rotating flying object can be obtained from the relational expression (5) based on the acceleration detection signal, and further, by measuring the distance L to the target, the distance L and the ground surface are measured. It is also possible to obtain the flight altitude H of the rotating projectile by substituting the elevation angle φ into the relational expression (6).

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
FIG. 1A is a configuration block diagram of a rotating flying object according to an embodiment of the present invention. In this figure, the rotating flying object M has a substantially cylindrical shape and is gradually reduced in diameter toward the tip, and flies while rotating. The rotary flying object M includes a first acceleration sensor 1, a second acceleration sensor 2, a differential amplifier 3, a radio wave radar 4, and an arithmetic processing unit 5 as internal configurations.

  FIG. 1B is a view taken along the line AA of the rotary projectile M. As shown in this figure, the 1st acceleration sensor 1 and the 2nd acceleration sensor 2 are installed in the position which becomes symmetrical with respect to a rotation center. The first acceleration sensor 1 and the second acceleration sensor 2 are, for example, piezoelectric acceleration sensors, which detect the centrifugal acceleration and the gravitational acceleration generated by the rotation of the rotary projecting body M, and according to their combined acceleration. Output a voltage signal. Here, the first voltage signal V <b> 1 output from the first acceleration sensor 1 is input to the positive phase input terminal of the differential amplifier 3 and is also input to the arithmetic processing unit 5. The second voltage signal V <b> 2 output from the second acceleration sensor 2 is input to the negative phase input terminal of the differential amplifier 3.

 The differential amplifier 3 takes the difference (V1−V2) between the first voltage signal V1 and the second voltage signal V2 and outputs the difference to the arithmetic processing unit 5 as the third voltage signal V3.

 The radio wave radar 4 is, for example, an FM-CW (frequency modulation continuous wave) radar, is installed at the tip of the rotating flying object M, and transmits a frequency modulation signal obtained by frequency modulation with a modulation signal of a predetermined frequency. The phase difference between the reflected wave radiated toward the target as a wave and the transmission wave reflected by the target and the transmission wave, specifically, the reflected wave and the transmission wave caused by the phase difference The distance L to the target is measured based on the frequency of the beat signal (beat frequency). The radio wave radar 4 outputs the distance data to the target obtained as described above to the arithmetic processing unit 5.

The arithmetic processing unit 5 detects the rotational speed of the main rotating projectile M based on the fluctuation period of the third voltage signal V3. Although details will be described later, the arithmetic processing unit 5 performs the following relational expression (5) regarding the elevation angle φ with respect to the ground surface of the rotating flying object M, the following relational expression (6) regarding the flight altitude H, and the gravitational acceleration g (9.8 m). / S ² ), and from the maximum value and minimum value of the first voltage signal V1, that is, from the maximum value A1 _max and the minimum value A1 _{min of} the combined acceleration A1 detected by the first acceleration sensor 1. By calculating the elevation angle φ with respect to the ground surface based on the relational expression (5), and further substituting the distance data (distance L) to the target obtained from the radio wave radar 4 and the elevation angle φ into the relational expression (6). The flight altitude H of the rotating projectile M is calculated.

 Next, the operation of the rotating projectile M configured as described above will be described.

 FIG. 2A is a schematic diagram showing the flight state of the rotating projectile M. As shown in this figure, it is assumed that the main rotating vehicle M is flying toward the target at an elevation angle φ with respect to the ground surface (horizontal plane). When the rotary projecting body M rotates in the illustrated rotation direction and the first acceleration sensor 1 exists at the position Pi at the rotation angle θ, the resultant acceleration A1 detected by the first acceleration sensor 1 is due to centrifugal force. Since it is a value obtained by subtracting the gravitational acceleration g from the centrifugal acceleration a, it is expressed by the following relational expression (1).

  Further, in the above case, since the second acceleration sensor 2 is installed at a position (position Pj) that is symmetric with respect to the first acceleration sensor 1 and the rotation center, the rotation angle θ in the relational expression (1). Is advanced by 180 °. Accordingly, the combined acceleration A2 detected by the second acceleration sensor 2 is represented by the following relational expression (2).

  FIG.2 (b) is a BB arrow line view of Fig.2 (a). In this figure, the positions of the first acceleration sensor 1 when the rotation angle θ = 0 °, 90 °, 180 °, and 270 ° are defined as positions P1, P2, P3, and P4, respectively.

 From the relational expressions (1) and (2), the change of the combined acceleration A1 and the combined acceleration A2 with respect to the rotation angle θ is as shown in FIG. As shown in this figure, the synthetic acceleration A1 and the synthetic acceleration A2 are cosine waves having an amplitude g · cos φ with respect to the centrifugal acceleration a, and a phase difference of 180 ° between the synthetic acceleration A1 and the synthetic acceleration A2. Exists. Taking such a difference (A1−A2) between the combined acceleration A1 and the combined acceleration A2, a cosine wave having an amplitude of 2 g · cos φ with respect to zero acceleration can be obtained as shown in FIG. Here, since the rotation angle θ indicates a change with time, the time during which the rotary projecting body M makes one rotation, that is, the time T until the first acceleration sensor 1 returns from the position P1 to the position P1 again. By detecting (repetition cycle), the rotation speed (1 / T) can be obtained.

 Note that if the repetition period of the maximum value 2g · cos φ of the waveform of FIG. 3B as described above is detected, the maximum value changes depending on the elevation angle φ with respect to the ground surface, so the maximum value is always monitored. There is a need. Therefore, in the present embodiment, the rotational speed is not detected by detecting the maximum value repetition period, but by detecting the time for returning from the position P2 where the amplitude becomes zero to the position P2 again in the waveform of FIG. Try to ask. Thus, since it is sufficient to detect the time when the amplitude is always zero, the rotational speed can be easily obtained without depending on the elevation angle φ with respect to the ground surface.

 Next, the reason for taking the difference between the combined acceleration A1 and the combined acceleration A2 as described above will be described. For example, when only the first acceleration sensor 1 is used, a waveform relating to the combined acceleration A1 as shown in FIG. 3A can be obtained. Therefore, the repetition cycle of a + g · cos φ, which is the maximum value of the combined acceleration A1, is set. If it is detected, the rotational speed can be obtained. Alternatively, the rotational speed can also be obtained by detecting a cycle in which the value of the combined acceleration A1 is equal to the centrifugal acceleration a.

 However, since the rotational speed of the rotating projectile M gradually decreases due to air resistance or the like, the centrifugal acceleration a is not constant. Furthermore, actually, since the rotary flying object M flies while performing a slight precession, the centrifugal acceleration “a” fluctuates in a certain cycle due to the influence of the precession. Therefore, when detecting the repetition cycle of a + g · cos φ which is the maximum value of the combined acceleration A1 as described above, or when detecting the cycle in which the value of the combined acceleration A1 is equal to the centrifugal acceleration a, the centrifugal acceleration a is There is a possibility that an accurate repetition period cannot be detected due to fluctuation, and there is a problem that signal processing becomes complicated if the repetition period is detected following the fluctuation of the centrifugal acceleration a.

Therefore, two acceleration sensors (the first acceleration sensor 1 and the second acceleration sensor 2) are provided as in the present embodiment, and the first voltage signal V1 and the second voltage signal V2 are provided by the differential amplifier 3.
, I.e., by taking the difference between the combined acceleration A1 and the combined acceleration A2, the influence of the centrifugal acceleration a can be canceled as shown in FIG. Signal processing can be simplified, and the rotational speed can be obtained accurately.

 As described above, the first acceleration sensor 1 outputs the first voltage signal V1 corresponding to the composite acceleration A1 as described above to the positive phase input terminal of the differential amplifier 3, and the second acceleration sensor. 2 outputs the second voltage signal V2 corresponding to the combined acceleration A2 to the negative phase input terminal of the differential amplifier 3. The first voltage signal V1 and the second voltage signal V2 show changes as shown in FIG. 3A, and the third voltage signal V3 output from the differential amplifier 3 is shown in FIG. Such a change is shown. The arithmetic processing unit 5 rotates by detecting a repetition period T in which the voltage value of the third voltage signal V3 input from the differential amplifier 3 is zero (the difference between the synthetic acceleration A1 and the synthetic acceleration A2 is zero). The number (1 / T) is calculated.

Next, a method for obtaining the elevation angle φ with respect to the ground surface from the relational expression (1) will be described. Assuming that the maximum value of the resultant acceleration A1 is A1 _max , A1 _max = a + g · cos φ as described above. Therefore, the elevation angle φ is expressed by the following relational expression (3), and when the minimum value of the combined acceleration A1 is A1 _min , the centrifugal acceleration a is expressed by the following relational expression (4).

  Substituting the relational expression (4) into the relational expression (3) yields the following relational expression (5).

Therefore, the arithmetic processing unit 5 detects the maximum value (voltage value corresponding to A1 _max ) and the minimum value (voltage value corresponding to A1 _min ) of the first voltage signal V1, and substitutes them into the relational expression (5). To calculate the elevation angle φ relative to the ground surface.

  Further, when the distance L to the target is obtained by the radio wave sensor 4, the flight altitude H of the rotating projectile M can be calculated from the following relational expression (6) from the elevation angle φ obtained as described above.

When the arithmetic processing unit 5 obtains the elevation angle φ based on the relational expression (5) from the first voltage signal V1 input from the first acceleration sensor 1 as described above, it is further input from the radio wave sensor 4. Based on the relational expression (6), the flight altitude H of the rotating projectile M is calculated from the distance data.
Such a flight altitude H is used as information or the like for the rotational projectile M to enter the landing system.

  The voltage signals V1 and V3 and the distance data as described above are all processed as digital signals in the arithmetic processing unit 5. That is, the voltage signals V1 and V3 are converted from an analog signal to a digital signal when input to the arithmetic processing unit 5, and distance data representing the distance L is output from the radio wave radar 4 as a digital signal.

  Further, as can be seen from the relational expressions (1) and (2), the rotational speed cannot be detected when the elevation angle φ with respect to the ground surface is 90 °. As described above, when the rotational speed M is to be detected when the rotational flying object M is flying perpendicularly to the ground surface, the rotational acceleration object M is detected by the first acceleration sensor 1 and the second acceleration sensor 2. It is necessary to make a precession with such a magnitude that gravitational acceleration (exactly g · cosφ) can be detected.

  As described above, according to the present rotating flying object M, the first acceleration sensor 1 and the second acceleration sensor 2 are used to combine the centrifugal acceleration and the gravitational acceleration that are generated when the rotating flying object M rotates. Since the accelerations A1 and A2 are detected and the rotational speed is detected based on the fluctuation period of the third electric signal V3 which is the difference between the first electric signal V1 and the second electric signal V2 corresponding to the accelerations A1 and A2, The rotational speed can be accurately detected without being affected by disturbances such as

 Furthermore, since the elevation angle φ with respect to the ground surface of the main rotating flying object M can be obtained from the first electric signal V1 corresponding to the combined acceleration A1, the distance L to the target is measured by the radio wave radar 4 so that the distance It is also possible to obtain the flight altitude H of the rotating projectile M from L and the elevation angle φ.

 In addition, this invention is not limited to the said embodiment, For example, the following modifications can be considered.

 In the above embodiment, the rotational speed of the rotating flying object M is detected. However, the present invention is not limited to this, and it is of course possible to detect the rotational speed of the rotating body fixed on the ground. In this case, if the rotation axis of the rotating body is horizontal with respect to the ground surface, the rotation speed can be detected without any problem. However, if the rotation axis is perpendicular to the ground surface, the rotation speed cannot be detected as in the above embodiment. However, even if the rotation axis is perpendicular to the ground surface, it is possible to detect the number of rotations when the rotating body is making a large precession while rotating.

It is a block diagram of the configuration of a rotating flying object M according to an embodiment of the present invention. It is a figure which shows the operation principle of the 1st acceleration sensor 1 and the 2nd acceleration sensor 2 in this embodiment. It is explanatory drawing of the rotation speed detection method in this embodiment.

Explanation of symbols

 DESCRIPTION OF SYMBOLS 1 ... 1st acceleration sensor, 2 ... 2nd acceleration sensor, 3 ... Differential amplifier, 4 ... Radio wave radar, 5 ... Arithmetic processing part, M ... Rotating flying object,

Claims (3)

An acceleration detection means for detecting a centrifugal acceleration and a gravitational acceleration generated by the rotation of the rotating body and outputting an acceleration detection signal corresponding to a combined acceleration of the centrifugal acceleration and the gravitational acceleration;
And a signal processing means for detecting the rotational speed of the rotating body based on a fluctuation period of the acceleration detection signal. Two acceleration detecting means are respectively provided at positions symmetrical with respect to the rotation center of the rotating body,
2. The rotational speed detection device according to claim 1, wherein the signal processing means detects the rotational speed of the rotating body based on a fluctuation cycle of a difference between acceleration detection signals respectively output from the two acceleration detection means. . A rotating flying object that flies while rotating toward a target,
Distance measuring means for measuring the distance to the target;
The rotation speed detection device according to claim 1 or 2,
The following relational expression (5) regarding the elevation angle φ with respect to the ground surface of the rotating flying object, the gravitational acceleration g, and the maximum value (maximum value of combined acceleration A1 _max ) and minimum value (minimum value of combined acceleration A1 _min ) of the acceleration detection signal. The elevation angle φ is calculated by the following equation, and the height H of the rotating projectile from the ground surface is expressed by the following relational expression (6) regarding the elevation angle φ, the distance L to the target, and the height H of the rotating projectile from the ground surface. A rotating flying object comprising: an arithmetic means for calculating

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