JPH1048228A - Method and equipment for measuring spinning speed of bullet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize highly accurate noncontact measurement of spinning speed of a bullet by measuring the spinning speed based on a sine wave signal produced from a photoelectric element depending on the spinning speed of a bullet being accelerated while spinning in a gun barrel. SOLUTION: A laser light 5 emitted from a laser light source 3 transmits through a first polarization plate 4 fixed to a bullet 1 and reflected on a mirror 6 disposed at the tip of the muzzle of a gun 2a. A reflected laser light 5 transmits through a second polarization plate 7 and an optical filter 8 before being received by a photoelectric element 9 and a sine wave signal 9a therefrom is recorded on a data recorder 10. The recorded data is processed and converted into a spinning speed. Output from the photoelectric element 9 is minimized when the polarization plate 4 is orthogonal to the polarization angle of the polarization plate 7 and minimized when they are aligned. Consequently, an output waveform comprising the sine wave signal 9a of the photoelectric element 9 is obtained every time when the bullet 1 spins by 90 deg. and a peak output appears. According to the arrangement, spinning speed can be detected at the time of shooting the bullet 1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for measuring the rotational speed of a bullet. It relates to a new improvement for measuring with accuracy.

[0002]

2. Description of the Related Art Conventionally, as a method of measuring a bullet rotation speed of this kind, a first conventional example is to mark a bullet with paint or the like, and at the time of firing the bullet is accelerated while rotating within a barrel. The rotation was imaged with a high-speed camera, and the rotation speed of the bullet was measured. Further, in the second conventional example, an acceleration sensor for the rotation direction is attached to a bullet, an acceleration signal from this acceleration sensor is recorded in a memory provided in the bullet, and data of the acceleration signal in the memory collected after shooting is obtained from: The rotation speed was calculated.

[0003]

Since the conventional method for measuring the rotational speed of a bullet has the above structure, the following problems exist. That is, in the method of monitoring the movement of the mark with the high-speed camera in the first conventional example, the ability to monitor the rotational position depends on the frame speed of the high-speed camera, and the recorded visible image is visually recognized by the human eye. It took a long time to find the rotation speed, and the error increased. In the method of attaching a rotation direction acceleration sensor to a bullet in the second conventional example, it is necessary to perform special processing for incorporating an acceleration sensor, a memory, a power supply, and the like into the bullet.
Further, since the acceleration sensor, the memory, and the like are built in the bullet, noise is generated in the sensor signal due to vibration or impact at the time of shooting, and it is difficult to perform accurate measurement.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problems. In particular, the present invention uses a laser beam to adjust the rotation speed of a bullet that is accelerated while rotating in a gun barrel during firing. It is an object of the present invention to provide a method and an apparatus for measuring a bullet rotation speed, which can be measured with high accuracy by using the method.

[0005]

According to the method of measuring a bullet rotation speed according to the present invention, a laser beam from a laser light source built in a bullet in a gun barrel is transmitted through a first polarizing plate, a mirror, a second polarizing plate, and an optical filter. A method of measuring the rotation speed by a sine wave signal obtained from the photoelectric device according to the rotation speed of the bullet, which is received by the photoelectric device and accelerated while rotating in the barrel.

According to the method of measuring a bullet rotation speed according to the present invention, a laser beam from a laser light source is made incident on a first mirror provided on a bullet in a barrel having a first polarizing plate via a second mirror and a half mirror. The reflected laser light reflected by the first mirror and obtained through the first polarizing plate and the half mirror is received by the photoelectric element through the second polarizing plate and the optical filter, and is accelerated while rotating in the barrel. A method of measuring the rotation speed by a sine wave signal obtained from the photoelectric element according to the rotation speed of the bullet.

[0007] A bullet rotation speed measuring device according to the present invention is a photoelectric conversion device for receiving laser light from a laser light source incorporated in a bullet in a barrel through a first polarizing plate, a mirror, a second polarizing plate, and an optical filter. An element and a data recorder connected to the photoelectric element, wherein the rotational speed is measured by a sine wave signal obtained from the photoelectric element according to the rotational velocity of the bullet accelerated while rotating in the barrel. Configuration.

A bullet rotation speed measuring device according to the present invention comprises a bullet provided in a barrel having a first polarizing plate and a first mirror, and a second bullet for making a laser beam incident on the first mirror.
A mirror and a half mirror, and a photoelectric element for receiving, via a second polarizing plate and an optical filter, reflected laser light reflected by the first mirror and obtained through the first polarizing plate and the half mirror, A data recorder connected to a photoelectric element, wherein the rotational speed is measured by a sine wave signal obtained from the photoelectric element in accordance with the rotational velocity of the bullet that is accelerated while rotating in the barrel.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the method and apparatus for measuring bullet rotation speed according to the present invention will be described below with reference to the drawings. FIG. 1 shows a first embodiment according to the present invention, in which a reference numeral 1 denotes a bullet loaded in a barrel 2, in which a known small laser light source 3 is mounted.
The laser beam 5 is emitted in the flight direction of the bullet 1 through a well-known first polarizing plate 4 provided at the tip of the bullet 1 by using a power supply (not shown).

This laser beam 5 is reflected by a mirror 6,
It is configured to be incident on a photoelectric element 9 composed of a photodiode having a known optical filter 8 via a known second polarizing plate 7. A sine wave signal 9a, which is an output signal obtained from the photoelectric element 9, is displayed and recorded as a waveform by the data recorder 10.

Next, the operation will be described. The laser light 5 emitted from the laser light source 3 embedded in the bullet 1
The light passes through the first polarizer 4 attached to the bullet 1 and the muzzle 2
The light is reflected by the mirror 6 at the end of a. The reflected laser light 5 is transmitted through the second polarizing plate 7 and the optical filter 8 and then received by the photoelectric element 9, and the sine wave signal 9 a of the photoelectric element 9 is recorded on the data recorder 10. This data recorder 10
Is converted into a rotation speed by an arithmetic processing such as a well-known FFT (fast Fourier transform). In addition, when the polarization angles of the first polarizing plate 4 and the second polarizing plate 7 are orthogonal, the output of the photoelectric element 9 becomes minimum, and when the polarizing angles of the first polarizing plate 4 and the second polarizing plate 7 match. As is well known, since the output of the photoelectric element 9 is maximized, the bullet 1
An output waveform consisting of the sine wave signal 9a of the photoelectric element 9 is obtained each time the peak is reached every time the image is rotated by 0 degrees. Therefore, the rotation speed at the time of one bullet firing can be detected.

FIG. 2 shows a second embodiment according to the present invention, in which a reference numeral 1 denotes a bullet loaded in a barrel 2, and a first mirror 11 and a first mirror 11 are provided at the tip of the bullet 1.
The polarizing plates 4 are provided in a laminated shape. A half mirror 12 and a second mirror 6 are disposed in front of a muzzle 2 a of the barrel 2, and the laser light 5 from the laser light source 3 reflected by the second mirror 6 is applied to the half mirror 12. And is reflected by the first mirror 11 to become a reflected laser beam 5A. The reflected laser beam 5A is transmitted to the half mirror 12
And is incident on the photoelectric element 9 via the second polarizing plate 7 and the optical filter 8. The sine wave signal 9a obtained from the photoelectric element 9 is displayed and recorded as a waveform by the data recorder 10.

Next, the operation will be described. Laser light source 3
Is reflected by the second mirror 6,
The component is divided into a component that transmits through the half mirror 12 and a component that reflects the half mirror 12. The laser light 5 transmitted through the half mirror 12
Transmits through the first polarizer 4 attached to the bullet 1, is reflected by the first mirror 11, and transmits through the first polarizer 4 again. The reflected laser light 5A transmitted through the first polarizing plate 4 is again divided into a transmitted component and a reflected component by a half mirror, and the reflected reflected laser light 5A is transmitted through the second polarizing plate 7 and the optical filter 8, and then the photoelectric element 9, the sine wave signal 9a of the photoelectric element 9 is displayed and recorded on the data recorder 10.

The data recorded in the data recorder 10 is later converted into a rotational speed by an arithmetic processing such as a well-known FFT (fast Fourier transform). Also, the first polarizing plate 4
And the polarization angle of the second polarizer 7 is orthogonal, the photoelectric element 9
Is the lowest, and when the polarization angles of the first polarizer 4 and the second polarizer 7 match, as is well known, the photoelectric element 9
Is maximum, so that an output waveform composed of the sine wave signal 9a of the photoelectric element 9 is obtained every time the bullet 1 reaches a peak every time the bullet 1 rotates 90 degrees. Therefore, the laser beam 5 is irradiated on the optical axis passing through the first polarizing plate 4 which rotates in accordance with the rotation of the bullet 1, and the reflected laser beam 5A reflected on the bullet 1 is again polarized, and then the photoelectric element 9 To receive light. The intensity of the reflected laser beam 5A that has received the two polarized lights changes in accordance with the rotation position of the bullet 1, and the rotation speed of the bullet 1 can be calculated from the output waveform (cycle of the wave-like waveform) of the photoelectric element 9. it can. In this measurement method, when the bullet 1 rotates at a constant speed, the intensity of the reflected laser beam 5A reflected has a sinusoidal waveform with a constant period. When the rotation speed changes, the sine wave shape changes every cycle to a cycle corresponding to the rotation speed. Therefore, the rotation speed can be calculated by calculating the change in the sine wave cycle from the data waveform of the intensity of the reflected laser beam 5A by performing a numerical operation process such as FFT (Fast Fourier Transform). Therefore, the rotation speed can be measured quantitatively in a non-contact manner, and high-accuracy data without noise due to vibration or impact can be obtained.

The optical filter 8 is a known filter that transmits only a component of light having a specific wavelength, and selects a transmission wavelength that matches the wavelength of the laser light 5. Since the photoelectric element 9 detects the light amount of a wide range of wavelengths (that is, the light intensity), the light amount may exceed the light amount range that can be detected only by the light amount of sunlight or illumination light. Further, even when the light amount does not exceed the detection range, the ratio of detecting the light amount of the laser beam 5 among the light amounts detected by the photoelectric element 9 is relatively reduced. descend. Therefore, other than laser beam 5 (sunlight, illumination light, etc.)
The optical filter 8 is used in order to cut off the light as much as possible and accurately detect a change in the amount of laser light by the photoelectric element 9. The optical filter 8 may be integrated with or separate from the photoelectric element 9. it can.

[0016]

As described above, the method and the apparatus for measuring the bullet rotation speed according to the present invention obtain the rotation speed using the data that changes in a sine wave shape in accordance with the rotation of the bullet using the laser beam. A highly accurate rotational speed signal can be easily measured.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing a first embodiment of a bullet rotation speed measuring method and device according to the present invention.

FIG. 2 is a configuration diagram showing a second embodiment of a bullet rotation speed measuring method and device according to the present invention.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 bullet 2 gun barrel 3 laser light source 4 first polarizing plate 5 laser light 5A reflected laser light 6 mirror (second mirror) 7 second polarizing plate 8 optical filter 9 photoelectric element 9a sine wave signal 11 first mirror

Claims (4)

[Claims] 1. A laser beam (5) from a laser light source (3) incorporated in a bullet (1) in a gun barrel (2) is supplied to a first polarizing plate (4), a mirror,
Photoelectric element via second polarizing plate (7) and optical filter (8)
(9), the rotation speed is obtained by a sine wave signal (9a) obtained from the photoelectric element (9) in accordance with the rotation speed of the bullet (1), which is accelerated while rotating in the barrel (2). A bullet rotation speed measurement method characterized by measuring the rotation speed. 2. A first mirror (11) provided on a bullet (1) in a gun barrel (2) and having a first polarizer (4) receives a laser beam (5) from a laser light source (3) on a second mirror. (6) and the reflected laser light (5A) reflected by the first mirror (11) and obtained through the first polarizing plate (4) and the half mirror (12). ) Is received by the photoelectric element (9) via the second polarizer (7) and the optical filter (8), and is rotated according to the rotation speed of the bullet (1) accelerated while rotating in the gun barrel (2). The photoelectric element
A bullet rotation speed measuring method, wherein the rotation speed is measured by a sine wave signal (9a) obtained from (9). 3. A laser beam (5) from a laser light source (3) incorporated in a bullet (1) in a gun barrel (2), a first polarizing plate (4), a mirror,
A photoelectric element (9) for receiving light via a second polarizing plate (7) and an optical filter (8); and a data recorder (10) connected to the photoelectric element (9). The rotation speed of the bullet (1) is measured by a sine wave signal (9a) obtained from the photoelectric element (9) according to the rotation speed of the bullet (1) accelerated while rotating in the bullet rotation speed. Measuring device. 4. A bullet (1) provided in a barrel (2) and having a first polarizing plate (4) and a first mirror (11);
1) a second mirror (6) and a half mirror (12) for allowing a laser beam (5) to be incident thereon, and the first polarizing plate (4) and a half mirror (12) reflected by the first mirror (11). The reflected laser light (5A) obtained through the second polarizing plate (7) and the optical filter
(8) comprising a photoelectric element (9) for receiving light, and a data recorder (10) connected to the photoelectric element (9), wherein the gun is accelerated while rotating in the barrel (2) The sine wave signal (9) obtained from the photoelectric element (9) according to the rotation speed of the bullet (1)
A bullet rotation speed measuring device, wherein the rotation speed is measured according to a).