TW201312078A - Optical fiber grating rotational goniometer - Google Patents

Abstract

The invention relates to an optical fiber grating rotational goniometer. The goniometer includes a shell, a rotational bar, an elastic bar and at least one fiber grating. The shell is a hollow tube. The two edges of the hollow tube dispose a first cover plate and a second cover plate, respectively. A first through hole for the rotational bar passing through is defined on the first cover plate. A second through hole for the elastic bar passing through is defined on the second cover plate. One edge of the rotational bar passes through the first through hole and resides in the shell. At least one first magnetic element is disposed on the rotational bar. The rotational bar can be rotated with respect to the first through hole. One edge of the elastic bar is disposed on the second through hole. At least one second magnetic element is disposed at the other edge of the elastic bar so that the second magnetic element is disposed corresponding to the first magnetic element. The two edges of the optical fiber grating are disposed at appropriate positions on the elastic rod. With the interaction between the first magnetic element and the second magnetic element, the central wavelength of the optical fiber grating is changed and therefore can measure a rotational angle. When the angle changes, the rotational bar rotates and actuates the first magnetic element. The second magnetic element displaces the same angle because of the interaction between the first magnetic element and the second magnetic element. Therefore, the shape of the elastic bar is changed and the optical grating is changed accordingly to form a central wavelength drift. With the central wavelength drift, the angle change of the rotational bar can be measured.

Description

Fiber grating rotary angle meter

The invention relates to a fiber grating rotary angle meter for a fiber grating angle meter, in particular to a force of a magnetic member and measuring an angle change.

Due to the invention and application of optical fiber, the optical fiber sensor is an all-optical path monitoring system, which has made a significant change in the traditional way of using copper wire as a transmission tool and an electronic component as a sensor. Fiber Bragg Grating sensors are used in a wide range of applications, not only for measuring pressure, temperature, humidity and concentration of gases, but also for dynamic signal detection of objects such as thrust, accelerator or torsion. A fiber grating angle sensor that uses the characteristics of rotation, torsion, and bending of a fiber grating to measure the angle of deformation of an object has become more and more popular in recent years.

The angle sensor can be applied to detect the rotational position for various relative angles. Fiber optic sensors are often combined with structural packages or composite materials for industrial applications, and their characteristics are used for rotation angle measurement. They are highly sensitive, immune to electromagnetic interference, and can be used in harsh environments. A rotational position sensor is fabricated by adhering a fiber grating to an elastic member. However, the conventional angle meter has the disadvantage that when measuring the rotational position, the number of revolutions in one direction is severely limited, that is, after performing the rotation angle measurement in a single direction for several weeks, it is necessary to apply the rotation in the opposite direction. continue to use. The application of the angle sensor to ships or aircraft, such as wind speed, wind direction, etc., is quite inconvenient.

The main object of the present invention is to solve the problem that the angle sensor has a severe limitation on the number of revolutions in one direction when the angle sensor is sensed by the rotation angle, and to provide a fiber grating rotary angle meter; for the above purpose, an optical fiber of the present invention The grating rotary angle meter includes a casing, a rotating rod, an elastic rod and at least one fiber grating, wherein: the casing is a hollow pipe body, and the two ends respectively have a first cover plate and a second cover plate, the first cover plate and the second cover plate respectively define a first through hole through which the rotating rod passes and a second through hole through which the elastic rod is inserted; the rotating rod is threaded at one end The first through hole is received in the housing, and at least one first magnetic member is disposed, and the rotating rod can be rotated in the first perforation; the elastic rod is disposed at one end of the second perforation, and the other end is mounted Providing at least one second magnetic member such that the second magnetic member is disposed opposite to the first magnetic member; and the two ends of the at least one fiber grating are attached to the elastic rod; by the first magnetic member and the second The force between the magnetic members indirectly causes the light The center wavelength of the grating changes, and thus can measure the rotation angle. When the angle changes, the rotating rod rotates and drives the first magnetic member, and the second magnetic member is offset by the same force with the force between the first magnetic member, so that the deformation of the elastic rod changes. The fiber grating causes a central wavelength shift due to its change, and the relative angular change of the rotating rod can be measured by using the drift of the central wavelength.

1 to 4 show a first embodiment of the present invention. The present invention is a fiber grating rotary angle meter comprising a housing 10, a rotating rod 20, an elastic rod 30 and at least one optical fiber. The grating 40, wherein the housing 10 is a hollow tube body, and the housing is provided for the rotating rod 20, the elastic rod 30 and the fiber grating 40, and the first end of the housing 10 has a first cover. The first cover 11 and the second cover 12 are respectively disposed at two ends of the housing, and the first cover 11 and the second cover 12 are respectively a first through hole 111 through which the rotating rod 20 passes and a second through hole 121 through which the elastic rod 30 is inserted, the rotating rod 20 is rotatably passed through the first through hole 111, and The first through hole 111 can be configured with at least one bearing 13 for the rotating rod 20 to pass through to increase the smoothness of the rotating rod 20 when rotating, and the elastic rod 30 is one end of the elastic rod 30 and is fixed to the second through hole 121. The rotating rod 20 is received in the casing 10 through one end of the first through hole 111, and at least one first magnetic body is disposed at a front end of one end of the casing 10. The first magnetic member is a magnet or a magnetic material, and the rotating rod 20 is rotatably movable in the first through hole 111. Further, the rotating rod 20 and the first magnetic member 21 can have a convenient relationship. The first magnetic member 21 is mounted on the disc 22, and the first magnetic member 21 is mounted on the disc 22 so as to deviate from the axis of the rotating rod 20. The elastic rod 30 is fixed at one end. The second through hole 121 forms a cantilever structure, and the other end is provided with at least one second magnetic member 31, and the second magnetic member 31 can be a ferromagnetic material corresponding to the first magnetic member 21 or a magnet, and the elastic rod 30 and the rotating rod 20 are correspondingly arranged to repel or attract the first magnetic member 21 and the second magnetic member 31; and the at least one fiber grating 40 is attached to the two ends The elastic rod 30 is adapted, and the fiber grating 40 can be pre-tensioned before being attached, so that the central wavelength shifts to a longer central wavelength, and the fiber grating 40 can be surface polished or has a surface diameter. Polished Bragg fiber grating, long-period fiber grating, period-graded fiber optic light Or superstructure FBG.

Please refer to FIG. 4 , which is a schematic diagram of the measurement architecture of the present invention. The fiber end 41 of the fiber grating 40 is connected to a light source 60 via one end of the fiber coupler 50 and connected to a spectrum analyzer 70 at the other end. The central wavelength of each of the fiber gratings is rotated by the rotation of the rotating rod 20, and the central wavelength difference before and after the drift of the central wavelength is the amount of drift of the central wavelength, and the amount of drift of the central wavelength is converted. The amount of change in the relative angle between the front and the rotation of the rotating rod 20 can be known.

In this embodiment, the number of the fiber gratings 40 is preferably two, and the fiber gratings 40 can be fiber gratings 40 of different or the same center wavelength. Referring again to FIG. 3, the two fiber gratings 40 are All of them are parallel to the axial direction of the elastic rod 30, and are preferably 90° from each other to the axis of the optical fiber grating 40 to the axial center of the elastic rod 30; and the first magnetic member 21 is a magnet. The second magnetic member 31 is a magnet or a ferromagnetic material corresponding to the first magnetic member 21, or the second magnetic member 31 is a magnet, and the first magnetic member 21 is the second magnetic member. In the magnet or ferromagnetic material corresponding to the piece 31, the mutual repulsive force or mutual attraction attraction between the first magnetic member 21 and the second magnetic member 31 is generated, and the second magnetic 31 member is deviated from the rotating rod. When the force of the first magnetic member 21 provided by the 20-axis is repelled or attracted, the elastic rod 30 will be bent and deformed by the force. At this time, the fiber grating 40 attached to the elastic rod 30 is subjected to the deformation. Stretching or compressing by the influence of the elastic rod 30, thereby making the center wavelength of the fiber grating 40 Health drift, the user can drift by the amount of the center wavelength and that the relative angle of rotation 20 of the rotating lever.

In the present invention, the magnetic force of the first magnetic member 21 or the second magnetic member 31 may be increased or the magnetic force between the first magnetic member 21 and the second magnetic member 31 may be increased to increase the force between the two magnetic members, so that the elastic rod The degree of deformation of 30 is increased, which in turn increases the central wavelength drift of the fiber grating 40, so that a larger wavelength shift of the fiber grating can be obtained at a fixed rotation angle, that is, the sensitivity is improved.

Moreover, adjusting the length of the elastic rod 30 and the position of the fiber grating 40 on the elastic rod 30 can also adjust the sensitivity of the fiber grating 40 rotary angle meter of the present invention, that is, when the fiber grating 40 is closer to the elastic rod 30 The fixed end, the greater the force it receives, the greater the central wavelength drift of the fiber grating at a fixed degree of rotation, ie, the sensitivity is improved.

In addition, the first magnetic 21 member of the present invention may be a U-shaped magnet or a flat-shaped magnet, and the bottom end of the U-shaped magnet or the center of the in-line magnet is disposed at one end of the rotating rod 20 and is accommodated in In the housing 10, the second magnetic member 31 is a magnet, and one of the second magnetic members 31 is magnetically corresponding to the first magnetic member, so that the second magnetic member 31 can be subjected to the first magnetic The force of the member 21 is offset, and the elastic rod 30 is deformed to cause the center wavelength of the fiber grating 40 to drift. The user can obtain the relative rotation angle of the rotating rod by the floating amount of the central wavelength. .

5 to FIG. 6 is a second embodiment of the present invention. The structure of the present embodiment is substantially the same as that of the first embodiment, except that the first magnetic member 21 is used in the present embodiment. The first magnetic member 21 is in the embodiment of the embodiment, and each of the first magnetic members 21 is mounted on the periphery of the disc 22 in a non-overlapping manner, and each of the second magnetic members 31 is subjected to the respective The resultant force of the first magnetic member 21 is offset, so that the elastic rod 30 is deformed to shift the central wavelength of the fiber grating 40, and the user can obtain the relative position of the rotating rod by the amount of drift of the central wavelength. Rotation angle.

In summary, the rotating structure of the fiber grating rotating angle meter of the invention can achieve the purpose of not only one-way rotation, and the number of revolutions is not limited, so compared with the known angle meter, In addition to being used for angle-related applications, it is more conducive to special applications such as wind speed and wind direction meter. The hair has indeed reached a breakthrough structure, and has improved creative content, while at the same time achieving industrial utilization and progress. Sex, and this creation is not seen in any publication, it is also novel. When it meets the provisions of Articles 21 and 22 of the Patent Law, it submits an application for a patent for invention according to law, and invites the examination committee of the bureau to grant a legal patent. Right, to pray.

Only the above-mentioned examples are only feasible examples of this creation, and the scope of the creation of the creation cannot be limited by it; that is, the equal changes and modifications made by the applicants in accordance with the scope of the patent application for this creation should still be covered by this creation patent. Within the scope.

10. . . case

11. . . First cover

111. . . First perforation

12. . . Second cover

121. . . Second perforation

13. . . Bearing

20. . . Rotating rod

twenty one. . . First magnetic piece

twenty two. . . disc

30. . . Elastic rod

31. . . Second magnetic piece

40. . . Fiber grating

41. . . Fiber end

50. . . Fiber coupler

60. . . light source

70. . . Spectral analysis

1 is a perspective view of a first embodiment of the present invention.

Figure 2 is a side cross-sectional view showing a first embodiment of the present invention.

3 is a schematic cross-sectional view showing a fiber grating and an elastic rod according to a first embodiment of the present invention.

4 is a schematic diagram of the measurement architecture of the present invention.

Figure 5 is a side cross-sectional view showing a second embodiment of the present invention.

Figure 6 is a front elevational view showing a second embodiment of the present invention.

10. . . case

11. . . First cover

111. . . First perforation

12. . . Second cover

121. . . Second perforation

13. . . Bearing

20. . . Rotating rod

twenty one. . . First magnetic piece

twenty two. . . disc

30. . . Elastic rod

31. . . Second magnetic piece

40. . . Fiber grating

Claims (9)

A fiber grating rotary angle meter includes a casing, a rotating rod, an elastic rod and at least one fiber grating, wherein: the casing is a hollow pipe body, and the two ends respectively have a first cover plate And a second cover plate, the first cover plate and the second cover plate respectively define a first through hole through which the rotating rod passes and a second through hole through which the elastic rod is inserted; the rotating rod is worn at one end The first perforation is received in the housing, and at least one first magnetic member is disposed, the rotating rod can be rotated in the first perforation; the elastic rod is disposed at one end of the second perforation, and the other end is Locating at least one second magnetic member such that the second magnetic member is disposed opposite to the first magnetic member; and the two ends of the at least one fiber grating are attached to the elastic rod; by the first magnetic member and the first The force between the two magnetic members indirectly causes a change in the center wavelength of the fiber grating, and thus the rotation angle can be measured. The fiber grating rotary angle meter of claim 1, wherein the first through hole further has at least one bearing for the rotating rod to pass through. The fiber grating rotary angle meter of claim 1, wherein the rotating rod and the first magnetic member further have a disc for facilitating the mounting of the first magnetic member, and the first magnetic member is The disc is mounted to deviate from the axis of the rotating rod. The fiber grating rotary angle meter according to claim 1 or 3, wherein the first magnetic member is a magnet, and the second magnetic member is a magnet or ferromagnetic corresponding to the first magnetic member. material. The fiber grating rotary angle meter according to claim 1 or 3, wherein the second magnetic member is a magnet, and the first magnetic member is a magnet or ferromagnetic corresponding to the second magnetic member. material. The fiber grating rotary angle meter according to claim 1, wherein the first magnetic member is a U-shaped magnet or a in-line magnet. The fiber grating rotary angle meter according to claim 1, wherein the number of the fiber gratings is two, and the two fiber gratings are parallel to the axial direction of the elastic rod, and each of the fibers is used. The connection between the axis of the grating and the axis of the elastic rod is preferably 90°. The fiber grating rotary angle meter according to claim 1, wherein the fiber grating is a Bragg fiber grating, a long-period fiber grating, a periodic gradient fiber grating or a super-surface polished or surface-polished surface. Structured fiber grating. A fiber grating rotary angle meter according to claim 1 or 8, wherein the fiber grating is a fiber grating having the same center wavelength.