Calibration system and calibration method for non-contact speedometers

Abstract

To provide a new system capable of calibrating a noncontact velocity meter.SOLUTION: A calibration system for a noncontact velocity meter includes: a rotating body 20 on which a noncontact velocity meter 10 to be calibrated can be fixed and which is configured to rotate; an angular velocity meter 30 that measures angular velocity of the rotating body 20; a circumferential velocity calculation section 301 that calculates circumferential velocity from the measured angular velocity and length from the center of rotation to the noncontact velocity meter 10; and a calibration signal generation section 302 that generates a calibration signal for calibrating the measured velocity of the noncontact velocity meter 10 on the basis of the circumferential velocity and the measured velocity measured by the noncontact velocity meter 10 rotating together with the rotating body 20.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a calibration system for a non-contact speedometer and a method for calibrating a non-contact speedometer.

Background Art

[0002] A non-contact speedometer can measure the speed of a measurement target without contact, and is used, for example, to measure the conveyance speed of a film wound around a roll. In order to maintain the accuracy of a non-contact speedometer, methods for calibrating the non-contact speedometer have been proposed (see, for example, Patent Documents 1 to 3).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Patent Document 3

Summary of the Invention

Problems to be Solved by the Invention

[0004] One object of the present invention is to provide a new system and method capable of calibrating a non-contact speedometer.

Means for Solving the Problems

[0005] A calibration system for a non-contact speedometer according to an aspect of the present invention includes a rotator configured to rotate and capable of fixing a non-contact speedometer to be calibrated, an angular velocity meter that measures the angular velocity of the rotator, a peripheral velocity calculation unit that calculates a peripheral velocity from the measured angular velocity and the length from the center of rotation to the non-contact speedometer, and a calibration signal generation unit that generates a calibration signal for calibrating the measurement speed of the non-contact speedometer based on the measurement speed measured by the non-contact speedometer rotating together with the rotator and the peripheral velocity.

[0006] In the calibration system for the non-contact speedometer described above, the rotating body may be configured to perform pendulum motion.

[0007] The calibration system for the non-contact speedometer described above may further include an axis positioned perpendicular to the direction of gravity, and the rotating body may rotate around the axis.

[0008] The calibration system for the non-contact speedometer described above may further include an object to be measured by the non-contact speedometer, which is parallel to the rotating body, and the non-contact speedometer may irradiate the object to be measured with light and measure the speed based on the reflected light from the object to be measured.

[0009] The above-described calibration system for a non-contact speedometer may further include a calibration signal transmitting unit for transmitting a calibration signal to the non-contact speedometer.

[0010] In the calibration system for the non-contact speedometer described above, the calibration signal may be configured to bring the measured speed closer to the peripheral speed.

[0011] The above non-contact speedometer calibration system may further include a chamber for maintaining a constant air pressure around the rotating body.

[0012] In the calibration system for the non-contact speedometer described above, a timestamp may be assigned to the measured speed. Alternatively, a timestamp may be assigned to the angular velocity. The calibration signal generation unit may compare the circumferential velocity, based on the measured speed and angular velocity transmitted at the same time, based on the timestamp.

[0013] Furthermore, a calibration method for a non-contact speedometer according to an aspect of the present invention includes fixing the non-contact speedometer to be calibrated to a rotatable rotating body, measuring the angular velocity of the rotating body, measuring the speed of the non-contact speedometer rotating together with the rotating body, calculating the peripheral velocity from the measured angular velocity and the distance from the center of rotation to the non-contact speedometer, and generating a calibration signal to calibrate the speed of the non-contact speedometer based on the speed and peripheral velocity.

[0014] In the above-described method for calibrating a non-contact speedometer, the rotating body may perform the motion of a pendulum.

[0015] In the above-described method for calibrating a non-contact speedometer, the rotating body may rotate about an axis disposed perpendicular to the direction of gravity.

[0016] In the above-described method for calibrating a non-contact speedometer, the non-contact speedometer may irradiate light on a measurement object parallel to the rotating body and measure a measurement speed based on the reflected light from the measurement object.

[0017] The above-described method for calibrating a non-contact speedometer may further include transmitting a calibration signal to the non-contact speedometer.

[0018] In the above-described method for calibrating a non-contact speedometer, the calibration signal may be configured to bring the measurement speed closer to the circumferential speed.

[0019] The above-described method for calibrating a non-contact speedometer may further include making the air pressure around the rotating body constant.

[0020] The above-described method for calibrating a non-contact speedometer may include attaching a time stamp to the measurement speed. Further, it may include attaching a time stamp to the angular velocity. In generating a calibration signal based on the time stamp, the measurement speed transmitted at the same time and the circumferential speed based on the angular velocity may be compared.

Advantages of the Invention

[0021] According to the present invention, it is possible to provide a new system and method capable of calibrating a non-contact speedometer.

Brief Description of the Drawings

[0022] [Figure 1] FIG. 1 is a schematic diagram showing a calibration system for a non-contact speedometer according to an embodiment. [Figure 2] FIG. 2 is a schematic diagram showing an optical speedometer of a surface shape measuring device according to an embodiment. [Figure 3] Figure 3 is a schematic diagram showing an optical speedometer of the surface shape measuring device according to the embodiment. [Figure 4] Figure 4 is a schematic diagram showing an optical speedometer of the surface shape measuring device according to the embodiment. [Figure 5] Figure 5 is a schematic graph showing the relationship between the peripheral speed and the measurement speed according to the embodiment. [Figure 6] Figure 6 is a schematic graph showing the relationship between the peripheral speed and the measurement speed according to the embodiment. [Figure 7] Figure 7 is a flowchart showing a calibration method of the non-contact speedometer according to the embodiment. [Figure 8] Figure 8 is a schematic diagram showing a calibration system of the non-contact speedometer according to the embodiment.

Mode for Carrying Out the Invention

[0023] Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following description of the drawings, the same or similar parts are denoted by the same or similar reference numerals. However, the drawings are schematic. Therefore, specific dimensions and the like should be determined in light of the following description. Of course, there are also parts where the dimensional relationships and ratios between the drawings are different from each other.

[0024] As shown in FIG. 1, the calibration system of the non-contact speedometer according to the embodiment can fix the non-contact speedometer 10 to be calibrated and is configured to rotate, a rotating body 20, an angular velocity meter 30 for measuring the angular velocity of the rotating body 20, a peripheral speed calculation unit 301 that calculates the peripheral speed from the measured angular velocity and the length from the center of rotation to the non-contact speedometer 10, and a calibration signal generation unit 302 that calculates a calibration signal for calibrating the measurement speed of the non-contact speedometer 10 based on the measurement speed measured by the non-contact speedometer 10 rotating together with the rotating body 20 and the peripheral speed.

[0025] The rotating body 20 has a shape such as a rectangular parallelepiped, but is not particularly limited. The rotating body 20 has a length. The rotating body 20 also has any structure on which the non-contact speedometer 10 can be mounted. The calibration system for the non-contact speedometer according to the embodiment further comprises an axis 31 positioned perpendicular to the direction of gravity, and the rotating body 20 may rotate in a plane parallel to the direction of gravity with the axis 31 as the center of rotation. As a result, the non-contact speedometer 10 fixed to the rotating body 20 performs pendulum motion with the axis 31 as the pivot point.

[0026] The calibration system may further include a measuring object 40 for the non-contact speedometer 10. The measuring object 40 is positioned parallel to the direction of gravity and parallel to the direction of rotation of the rotating body 20. The measuring object 40 has, for example, a plane parallel to the direction of rotation of the rotating body 20. The surface of the measuring object 40 may be covered with a reflective material. The reflective material is made of a material with high light reflectivity, such as metal. The measuring object 40 is, for example, fixed and does not move. The shaft 31 may be provided perpendicular to the measuring object 40.

[0027] The non-contact speedometer 10 may be an optical speedometer. If the non-contact speedometer 10 is an optical speedometer, the non-contact speedometer 10 irradiates the object to be measured 40 with light and calculates the speed of the non-contact speedometer 10 relative to the object to be measured 40 based on the reflected light from the object to be measured 40.

[0028] The optical speedometer may also be a laser Doppler speedometer. If the non-contact speedometer 10 is a laser Doppler speedometer, the non-contact speedometer 10 includes a light source 201 that emits laser light, as shown in Figure 2. The laser light passes through a collimating lens 202 and is split into two by a half mirror 203. One of the split laser beams is reflected by a mirror 204, and the two laser beams each enter the object to be measured 40 at an incident angle θ and interfere with each other. The scattered light reflected by the object to be measured 40 is focused by a focusing lens 205 and received by a light-receiving element 206.

[0029] The relationship between the frequency F of the Doppler signal obtained from the photodetector 206, the velocity V of the non-contact speedometer 10 relative to the object to be measured 40, the wavelength λ of the laser light, and the incident angle θ of the laser light is given by equation (1) below. F=(2V / λ)sinθ (1) The wavelength λ of the laser light and the incident angle θ of the laser light can be obtained in advance. The frequency F of the Doppler signal can be obtained by performing a Fourier transform on the time change of the light received by the photodetector 206. Therefore, by obtaining the frequency F of the Doppler signal, the non-contact speedometer 10 calculates the speed V of the non-contact speedometer 10 relative to the object to be measured 40.

[0030] The non-contact speedometer 10 may be a self-coupling speedometer. If the non-contact speedometer 10 is a self-coupling speedometer, it includes a light source 211 that emits laser light, as shown in Figure 3. The laser light is incident on the object to be measured 40. The scattered light reflected by the object to be measured 40 travels in the reverse direction along the same optical path as the incident light, and the reflected light that re-enters the optical resonator in the light source 211 interferes with the laser light generated in the optical resonator. This interference means that a self-coupling effect occurs in the optical resonator. The interference waveform generated by the self-coupling is detected by the photodetector 212. Based on the period of the interference waveform, the non-contact speedometer 10 calculates the speed of the non-contact speedometer 10 relative to the object to be measured 40.

[0031] The non-contact speedometer 10 may be a spatial filter type speedometer. If the non-contact speedometer 10 is a spatial filter type speedometer, it includes a light source 221 that emits light, as shown in Figure 4. The object to be measured 40 is illuminated from an oblique direction with focused light so as to provide dark-field illumination to the light-receiving optical system of the non-contact speedometer 10. The light scattered by the object to be measured 40 is focused by a focusing lens 222 and forms an image of the object to be measured 40 on a grating 223 having a periodic transmittance distribution.

[0032] If the magnification of the light-receiving optical system is M and the speed of the non-contact speedometer 10 relative to the object to be measured 40 is V, then the image on the grating 223 moves at a speed of MV. The transmitted light from the grating 223 is received by the light-receiving element 224. The period F of the signal of the transmitted light received by the light-receiving element 224 is given by equation (2) below, where p is the spacing of the gratings 223. F = MV / p (2) Since the magnification M of the light-receiving optical system and the spacing p of the grating 223 can be obtained in advance, the non-contact speedometer 10 calculates its speed V relative to the object 40 by measuring the frequency F.

[0033] For example, the non-contact speedometer 10 and the object to be measured 40 are positioned such that the reflected light from the object to be measured 40 to the non-contact speedometer 10 is perpendicular to the direction of gravity, as shown in Figure 1. This makes it possible to suppress the effects of rolling or yawing on the object to be measured 40.

[0034] The angular velocity meter 30 calculates the angular velocity by measuring the change in angle of the rotating body 20 per unit time. The part of the angular velocity meter 30 that measures the change in angle and the part that calculates the angular velocity from the measured angle may be separate. The angular velocity meter 30 may also consider the change in angle of the rotating shaft 31 as the change in angle of the rotating body 20.

[0035] The calibration system for a non-contact speedometer according to the embodiment may further include a control unit 304 for controlling at least one of the non-contact speedometer 10 and the angular velocity meter 30 via wired or wireless means. The control unit 304 controls the start and stop of speed measurement by the non-contact speedometer 10. The control unit 304 controls the start and stop of angular velocity measurement by the angular velocity meter 30.

[0036] The peripheral speed calculation unit 301 calculates the peripheral speed of the non-contact speed meter 10, which is in pendulum motion, from the measured angular velocity and the length from the center of rotation to the non-contact speed meter 10. The peripheral speed calculation unit 301 may consider the length of the rotating body 20 to be the length from the center of rotation to the non-contact speed meter 10.

[0037] The calibration signal generation unit 302 generates a calibration signal to bring the measured speed closer to the peripheral speed. The non-contact speedometer 10 transmits the measured speed to the calibration signal generation unit 302 via wired or wireless connection. The peripheral speed calculation unit 301 transmits the peripheral speed to the calibration signal generation unit 302 via wired or wireless connection. The calibration signal generation unit 302 receives the measured speed from the non-contact speedometer 10 and the peripheral speed from the peripheral speed calculation unit 301.

[0038] The calibration signal generation unit 302 compares the measured speed with the peripheral speed. For example, as shown in Figure 5, if the measured speed and the peripheral speed are the same, the calibration signal generation unit 302 does not generate a calibration signal. As shown in Figure 6(a), if the measured speed is faster than the peripheral speed, the calibration signal generation unit 302 generates a calibration signal to calibrate the measured speed so that it becomes equal to the peripheral speed. As shown in Figure 6(b), if the measured speed is slower than the peripheral speed, the calibration signal generation unit 302 generates a calibration signal to calibrate the measured speed so that it becomes equal to the peripheral speed.

[0039] The calibration signal is not particularly limited as long as it can calibrate the measured speed of the non-contact speedometer 10 shown in Figure 1. For example, the calibration signal may include a coefficient or formula multiplied by the measured speed calculated by the non-contact speedometer 10. Alternatively, the calibration signal may be a signal that calibrates the sensitivity of the optical system used by the non-contact speedometer 10 to calculate the measured speed, or the intensity and frequency of the electrical signals of the electrical circuit.

[0040] The calibration system for a non-contact speedometer according to the embodiment further includes a calibration signal transmission unit 303 for transmitting a calibration signal generated by a calibration signal generation unit 302 to a non-contact speedometer 10. The non-contact speedometer 10 is configured to receive the calibration signal and calculate the calibrated measurement speed based on the calibration signal.

[0041] The peripheral speed calculation unit 301, the calibration signal generation unit 302, the calibration signal transmission unit 303, and the control unit 304 are included, for example, in a central processing unit (CPU) 300.

[0042] Next, with reference to Figure 7, a calibration method for a non-contact speedometer according to an embodiment will be described.

[0043] In step S101, the non-contact speedometer 10 is placed on the rotating body 20. In step S102, the angular velocity meter 30 starts measuring the angular velocity at the instruction of the control unit 304, and in step S103, the non-contact speedometer 10 starts measuring the measured speed at the instruction of the control unit 304.

[0044] In step S104, the rotating body 20 is raised to an arbitrary height, and the pendulum motion of the rotating body 20 is started. While the rotating body 20 is in pendulum motion, the angular velocity meter 30 continues to measure the angular velocity, and the non-contact speedometer 10 continues to measure the measured speed. The angular velocity meter 30 transmits the measured angular velocity to the peripheral speed calculation unit 301, which calculates the peripheral speed and transmits the calculated peripheral speed to the calibration signal generation unit 302. The non-contact speedometer 10 transmits the measured measured speed to the calibration signal generation unit 302. Then, in step S105, the pendulum motion of the rotating body 20 is stopped, the angular velocity meter 30 stops measuring the angular velocity, and the non-contact speedometer 10 stops measuring the measured speed. The pendulum motion of the rotating body 20 may be forcibly stopped or may be allowed to stop naturally.

[0045] In step S106, the calibration signal generation unit 302 generates a calibration signal based on the received peripheral speed and measured speed. In step S107, the calibration signal transmission unit 303 transmits the calibration signal generated by the calibration signal generation unit 302 to the non-contact speedometer 10. The non-contact speedometer 10 receives the calibration signal and is configured to calculate the calibrated measured speed thereafter.

[0046] Although the present invention has been described above by embodiments, the descriptions and drawings that constitute part of this disclosure should not be understood as limiting the invention. Various alternative embodiments, examples, and operational techniques should become apparent to those skilled in the art from this disclosure.

[0047] For example, as shown in Figure 8, the calibration system for the non-contact speedometer according to the embodiment may further include a time information providing device 400 that assigns time stamps to the measured speed and angular velocity. The time information providing device 400 communicates with the non-contact speedometer 10 and the angular velocity meter 30 via wired or wireless means and transmits time information to the non-contact speedometer 10 and the angular velocity meter 30. The time information providing device 400 may be connected to an access point of the CPU 300 for wireless connection with the non-contact speedometer 10 and the angular velocity meter 30.

[0048] The non-contact speedometer 10 adds a timestamp to the measured speed based on time information when transmitting the measured speed. The angular velocity meter 30 adds a timestamp to the peripheral speed based on time information when transmitting the angular velocity. The calibration signal generation unit 302 compares the measured speed transmitted at the same time with the peripheral speed based on the angular velocity, based on the timestamp. This makes it possible to generate a highly accurate calibration signal.

[0049] Furthermore, the motion of the pendulum is affected by the ambient air pressure. Therefore, the calibration system for the non-contact speedometer according to the embodiment may include a chamber that houses the rotating body 20 that performs the pendulum motion and can maintain a constant internal air pressure. For example, the chamber may be equipped with a pressure sensor that detects the internal air pressure, pressurizing the chamber if the internal air pressure decreases and depressurizing the chamber if the internal air pressure increases.

[0050] Thus, it should be understood that the present invention encompasses various embodiments and the like that are not described herein. [Explanation of symbols]

[0051] 10...Non-contact speedometer, 20...Rotating body, 30...Angular velocity meter, 31...Axis, 40...Measurement target, 201...Light source, 202...Collimating lens, 203...Half mirror, 204...Mirror, 205...Concentrating lens, 206...Light receiving element, 211...Light source, 212...Light receiving element, 221...Light source, 222...Concentrating lens, 223...Grid, 224...Light receiving element, 301...Peripheral speed calculation unit, 302...Calibration signal generation unit, 303...Calibration signal transmission unit, 304...Control unit, 400...Time information providing device

Claims

1. A rotating body configured to rotate and to be able to fix the non-contact speedometer to be calibrated, An angular velocity meter for measuring the angular velocity of the rotating body, A peripheral speed calculation unit calculates the peripheral speed from the measured angular velocity and the distance from the center of rotation to the non-contact speed meter. A calibration signal generation unit generates a calibration signal for calibrating the measured speed of the non-contact speed meter based on the measured speed measured by the non-contact speed meter, which rotates together with the rotating body, and the peripheral speed. The object to be measured by the non-contact speed meter, parallel to the rotating body, Equipped with, The non-contact speedometer irradiates the object to be measured with light and measures the speed based on the reflected light from the object to be measured. Calibration system for non-contact speedometers.

2. The calibration system for a non-contact speedometer according to claim 1, wherein the rotating body is configured to perform pendulum motion.

3. It further includes an axis positioned perpendicular to the direction of gravity, The rotating body rotates around the axis, Calibration system for a non-contact speedometer according to claim 1 or 2.

4. A calibration system for a non-contact speedometer according to any one of claims 1 to 3, further comprising a calibration signal transmitting unit for transmitting the calibration signal to the non-contact speedometer.

5. Calibration system for a non-contact speedometer according to any one of claims 1 to 4, wherein the calibration signal is configured to bring the measured speed closer to the peripheral speed.

6. A calibration system for a non-contact speedometer according to any one of claims 1 to 5, further comprising a chamber for maintaining a constant air pressure around the rotating body.

7. The non-contact speedometer to be calibrated is fixed to a rotatable rotating body, Measuring the angular velocity of the rotating body, The non-contact speedometer, which rotates together with the rotating body, irradiates light onto an object to be measured parallel to the rotating body, and measures the speed based on the reflected light from the object to be measured. The peripheral velocity is calculated from the measured angular velocity and the distance from the center of rotation to the non-contact speedometer. Based on the measured speed and the peripheral speed, a calibration signal is generated to calibrate the measured speed of the non-contact speedometer. A calibration method for a non-contact speedometer, including the above.

8. The method for calibrating a non-contact speedometer according to claim 7, further comprising transmitting the calibration signal to the non-contact speedometer.

9. The calibration method for a non-contact speedometer according to claim 7 or 8, wherein the calibration signal is configured to bring the measured speed closer to the previous circumferential speed.

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