CN115014606B - Fiber bragg grating dynamic torque measuring device and measuring method based on off-axis interconnector - Google Patents

Abstract

An off-axis interconnector-based optical fiber grating dynamic torque measurement device and measurement method, there is an off-axis interconnector composed of a flat disk and a tapered cylindrical disk, the diameter of the cone bottom surface of the tapered disk is the same as that of the flat disk The same diameter, and a set distance from one surface of the flat disk is set relative to the center. The center of the flat disk and the conical cylindrical disk is coaxially formed with a through hole. The ASE broadband light source is connected to the conical The incident light port on the disc is connected to the exit light port on the conical disc by the fiber grating demodulator, and an optical fiber connected to the incident light port on the planar disc is set on the side of the planar disc away from the conical disc. The collimator and the fiber collimator connected to the exit light port of the flat disc, the other ends of the two fiber collimators are respectively connected to the circulator, and the circulator is connected to the fiber grating strain gauge pasted on the measured elastic shaft through the fiber optic connector. piece. The invention is capable of performing dynamic torque measurement under the condition that the central part of the rotating part is occupied under strong interference.

Description

Fiber Bragg grating dynamic torque measurement device and measurement method based on off-axis interconnector

technical field

The invention relates to the measurement of the dynamic torque of an optical fiber grating. In particular, it relates to a fiber grating dynamic torque measurement device and measurement method based on an off-axis interconnector.

Background technique

Torque measurement is widely used in ships, automobiles and other fields. Torque measurement is often difficult to measure accurately in very complex environments, especially in severe conditions such as severe vibration, strong electromagnetic interference, high temperature and high humidity, and even underwater , compared with other torque measurement methods, fiber gratings can play a role that other electrical sensors cannot play in this environment. With the rapid development of optical fiber technology, optical fiber rotary connectors have been widely used in military defense, industrial control, energy and medical fields. In some equipment or devices, it is necessary to communicate with each other between relatively rotating parts, such as video signals, audio signals, control signals, sensor signals, etc. The common feature of most existing optical fiber rotary connectors is the transmission of optical signals Occupies the central axis of rotation position. In the process of some complex optical signal transmission, sometimes it is accompanied by the transmission of other media such as electrical signals or a mechanical transmission shaft is left. When the axis of the rotating part is occupied, the general optical fiber rotary connector is not suitable. Therefore, there is an urgent need for an off-axis dynamic torque measurement method that can resist strong interference and can realize bidirectional signal transmission.

Contents of the invention

The technical problem to be solved by the present invention is to provide an off-axis interconnector-based fiber grating dynamic torque measurement that can perform dynamic torque measurement under strong interference and when the central part of the rotating part is occupied. Torque measuring device and measuring method.

The technical solution adopted by the present invention is: a fiber grating dynamic torque measurement device based on an off-axis interconnector, including an ASE broadband light source for providing a measurement light source and obtaining the dynamic torque measurement of the measured elastic shaft according to the received reflected light signal The resulting fiber grating demodulator is also provided with an off-axis interconnector, the off-axis interconnector is composed of a flat disk and a tapered cylindrical disk, and the diameter of the cone base of the tapered disk is the same as that of the plane The diameters of the disks are the same, and the bottom surface of the cone is arranged opposite to one surface of the plane disk with a set distance. The ASE broadband light source is connected to the first incident light port on the tapered disk through the first incident fiber collimator, and the fiber grating demodulator is connected to the first incident fiber collimator through the first exit fiber collimator. The first exit light port on the tapered disc, a second incident optical fiber with one end connected to the second incident light port on the planar disc is provided on the side of the planar disc away from the tapered disc. A collimator and a second exit fiber collimator whose one end is connected to the second exit light port of the planar disc, and the other ends of the second incident fiber collimator and the second exit fiber collimator are respectively connected to the circulator The two ends of the circulator are connected to the fiber grating strain gauge pasted on the measured elastic shaft through the fiber optic connector.

The second light exit port and the second light entrance port on the planar disk are respectively formed on the disk surface around the central through hole.

The first light incident port and the first light exit port on the tapered disk are respectively formed on the inclined side surfaces of the tapered disk.

During measurement, the measured elastic shaft is fixedly connected to the plane disc, and is movably connected to the conical disc.

A method for measuring a fiber grating dynamic torque measuring device based on an off-axis interconnector, comprising the steps of:

1) The ASE broadband light source passes through the first incident fiber collimator, and the optical signal is input from one side of the tapered cylindrical disk, and output from the other side, adjust the incident angle of the first incident fiber collimator, observe the output results, and calculate Optical signal loss, find the angle of incidence with the smallest transmission loss;

2) The first incident fiber collimator is fixed on the first incident light port on the tapered cylindrical disc according to the incident angle with the smallest transmission loss, and the measured elastic axis passes through the plane disc and the tapered cylindrical disc in turn, And the measured elastic shaft is fixedly connected with the plane disk, and is movably connected with the tapered cylindrical disk; the fiber grating strain gauge connected with the circulator through the optical fiber is pasted on the measured elastic shaft, and passed through the external The rotation of the motor applies torque to the measured elastic shaft;

3) The ASE broadband light source passes through the first incident fiber collimator, and the optical signal is input from one side of the conical cylindrical disc, and after multiple reflections between the planar disc and the conic cylindrical disc, the optical signal is transmitted from the first The second output light exits, and enters the circulator through the collimator and optical fiber, and then enters the fiber grating strain gauge through the circulator;

4) The narrow-band light of the central wavelength reflected by the fiber Bragg grating strain gauge passes through the second incident light of the circulator, the collimator and the flat disk and enters the conical cylindrical disk again. The first output fiber collimator on the first output port of the disc outputs to the fiber grating demodulator, and the current torque value is obtained through the fiber grating demodulator.

The fiber grating dynamic torque measurement device and measurement method based on the off-axis interconnector of the present invention can perform dynamic torque measurement under strong interference and when the central part of the rotating part is occupied, and has the advantages of high coupling efficiency, dynamic transmission, and processability Sideshaft transmission and other features. In terms of economic benefits, it can be widely used in occasions that require CT scanning, rotary connection of optical signals, etc.

Description of drawings

Fig. 1 is the structural representation of the fiber grating dynamic torque measurement device based on the off-axis interconnector of the present invention;

Fig. 2 is a schematic view of the front structure of a cone-cylindrical disk in the present invention;

Fig. 3 is a schematic view of the side structure of a cone-cylindrical disk in the present invention;

Fig. 4 is a schematic diagram of the front structure of a plane disk in the present invention;

Fig. 5 is a schematic diagram of the side structure of the plane disk in the present invention.

in the picture

1: ASE broadband light source 2: Measured elastic axis

3: Fiber Bragg grating demodulator 4: Circulator

5: Fiber Bragg grating strain gauge 6: Plane disc

7: Tapered cylindrical disk 8: Second exit fiber collimator

9: Second incident fiber collimator 10: First incident fiber collimator

11: The first exit fiber collimator 12: The first exit light port

13: The first incident light port 14: The second exit light port

15: Second incident light port

Detailed ways

The off-axis interconnector-based fiber grating dynamic torque measurement device and measurement method of the present invention will be described in detail below in conjunction with the embodiments and drawings.

As shown in Fig. 1, Fig. 2, Fig. 3, Fig. 4 and Fig. 5, a kind of fiber grating dynamic torque measuring device based on an off-axis interconnector of the present invention includes an ASE broadband light source 1 for providing a measurement light source and according to The fiber grating demodulator 3 that receives the reflected light signal to obtain the dynamic torque measurement result of the measured elastic shaft 2 is also provided with an off-axis interconnector. The off-axis interconnector is composed of a flat disc 6 and a cone Disc 7 constitutes, the conical bottom surface diameter of described conical disc 7 is the same as the diameter of plane disc 6, and described conical bottom surface and a face of plane disc 6 are oppositely arranged and spaced at a set distance, and the plane The center of the disk 6 and the conical cylindrical disk 7 are coaxially formed with a through hole for penetrating the measured elastic axis 2, and the ASE broadband light source 1 is connected to the conical disk through the first incident fiber collimator 10 7, the first incident light port 13 on the fiber grating demodulator 3 is connected to the first exit light port 12 on the tapered disk 7 through the first outgoing fiber collimator 11, and the flat disk 6 The side away from the tapered disc 7 is provided with a second incident optical fiber collimator 9 whose end is connected to the second incident light port 15 on the planar disc 6 and a second incident fiber collimator 9 whose end is connected to the second incident light port 15 of the planar disc 6 . The second exit fiber collimator 8 connected to the exit light port 14, the other end of the second incident fiber collimator 9 and the second exit fiber collimator 8 are respectively connected to the two ends of the circulator 4, the circulator 4 Connect the fiber grating strain gauge 5 pasted on the measured elastic shaft 2 through the fiber optic connector.

As shown in FIG. 2 and FIG. 3 , the first light incident port 13 and the first light exit port 12 on the conical disc 7 are respectively formed on the oblique side surfaces of the conical disc 7 .

As shown in FIG. 4 and FIG. 5 , the second light exit port 14 and the second light entry port 15 on the planar disk 6 are respectively formed on the disk surface around the central through hole.

A fiber grating dynamic torque measurement device based on an off-axis interconnector of the present invention, during measurement, the measured elastic shaft 2 is fixedly connected to the plane disc 6, and is connected to the tapered disc 7 for active connections.

The measuring method of the fiber grating dynamic torque measuring device based on the off-axis interconnector of the present invention comprises the following steps:

1) The ASE broadband light source 1 passes through the first incident fiber collimator 10, and the optical signal is input from one side of the tapered cylindrical disc 7 and output from the other side, and the incident angle of the first incident fiber collimator is adjusted to observe the output result , by calculating the amount of optical signal loss, find the incident angle with the smallest transmission loss;

2) The first incident optical fiber collimator 10 is fixed on the first incident light port 13 on the tapered cylindrical disc 7 according to the incident angle with the smallest transmission loss, and the measured elastic axis 2 passes through the plane disc 6 and the Tapered cylindrical disc 7, and the measured elastic shaft 2 is fixedly connected with the plane disc 6, and is movably connected with the tapered cylindrical disc 7; the fiber grating strain gauge connected to the circulator 4 through an optical fiber 5 Paste on the measured elastic shaft 2, and apply torque to the measured elastic shaft 2 through the rotation of the external motor;

3) The ASE broadband light source 1 passes through the first incident optical fiber collimator 10, and the optical signal is input from one side of the tapered cylindrical disk 7, and after multiple reflections between the plane disk 6 and the tapered cylindrical disk 7, it is transmitted from the The second exit port 14 of the plane disk 6 exits, and enters the circulator 4 through the collimator 8 and the optical fiber, and then enters the fiber grating strain gauge 5 through the circulator 4;

4) When the external motor rotates and applies a torque M to the measured elastic shaft 2, the measured elastic shaft 2 with a length of L is twisted to generate a strain τ, that is, a torsional deformation occurs. Assuming that the deformation is small at this time, the measured elastic shaft 2 The length and cross-sectional area do not change, and any two cross-sections of the measured elastic shaft 2 rotate relative to the central axis, thereby generating a torsion angle. When the shear stress on the measured elastic shaft 2 does not exceed the bearing capacity of the material At the limit, the torque M is expressed as:

Wherein, r is the radius of the cross-section of the measured elastic shaft; I is the polar moment of inertia of the measured elastic shaft; G is the shear modulus of the material; τ is the maximum shear strain at the surface of the measured elastic shaft;

The fiber grating strain gauge 5 pasted on the measured elastic shaft 2 reflects narrow-band light with a wavelength corresponding to the torque value _. This wavelength is the central wavelength of the narrow-band light, which is denoted as λ _B . The strain τ has the following relationship:

Among them, α is the angle between the FBG strain gauge and the axis of the measured elastic axis, and K _ε is the strain sensitivity coefficient of the FBG strain gauge;

Based on the above-mentioned principle, the narrow-band light reflected by the fiber grating strain gauge 5 at the central wavelength passes through the circulator 4, the collimator 9 and the second incident light 15 of the plane disk 6 to enter the tapered cylindrical disk 7 again, After multiple reflections, it is finally output to the fiber grating demodulator 3 from the first exit fiber collimator 11 connected to the first exit light port 12 of the tapered cylindrical disk 7, and the current torque value.

Claims (2)

1. The fiber bragg grating dynamic torque measuring device based on the off-axis interconnector comprises an ASE broadband light source (1) for providing a measuring light source and a fiber bragg grating demodulator (3) for obtaining a dynamic torque measuring result of a measured elastic shaft (2) according to a received reflected light signal, and is characterized by further comprising the off-axis interconnector, wherein the off-axis interconnector is composed of a plane disc (6) and a cone cylindrical disc (7), the diameter of the cone bottom surface of the cone cylindrical disc (7) is the same as that of the plane disc (6), the cone bottom surface and one surface of the plane disc (6) are oppositely arranged and are separated by a set distance, through holes for penetrating the measured elastic shaft (2) are coaxially formed in the centers of the plane disc (6) and the cone cylindrical disc (7), the ASE broadband light source (1) is connected with a first incident light port (13) on the cone cylindrical disc (7) through a first incident fiber collimator (10), the fiber bragg grating demodulator (3) is connected with a first emergent light port (12) on the cone cylindrical disc (7) through a first emergent collimator (11), a second incident optical fiber collimator (9) with one end connected with a second incident light port (15) on the plane disc (6) and a second emergent optical fiber collimator (8) with one end connected with a second emergent light port (14) of the plane disc (6) are arranged on one side, far away from the conical cylindrical disc (7), of the plane disc (6), the other ends of the second incident optical fiber collimator (9) and the second emergent optical fiber collimator (8) are respectively connected with two ends of a circulator (4), and the circulator (4) is connected with a fiber bragg grating strain gauge (5) adhered on a tested elastic shaft (2) through an optical fiber connector;

a second emergent light port (14) and a second incident light port (15) on the plane disc (6) are respectively formed on the disc surface around the center through hole;

a first incident light port (13) and a first emergent light port (12) on the conical cylindrical disk (7) are respectively formed on the inclined side surfaces of the conical cylindrical disk (7);

during measurement, the measured elastic shaft (2) is fixedly connected with the plane disc (6) and is movably connected with the conical cylindrical disc (7).

2. A method of measuring an off-axis interconnect based fiber grating dynamic torque measurement apparatus as defined in claim 1, comprising the steps of:

1) An ASE broadband light source (1) inputs an optical signal from one surface of a conical cylindrical disc (7) through a first incident optical fiber collimator (10), outputs the optical signal from the other surface, adjusts the incident angle of the first incident optical fiber collimator, observes the output result, and finds the incident angle with the minimum transmission loss by calculating the loss of the optical signal;

2) The first incident optical fiber collimator (10) is fixed on a first incident light port (13) on the conical cylindrical disc (7) according to an incident angle with minimum transmission loss, the elastic shaft (2) to be tested sequentially penetrates through the planar disc (6) and the conical cylindrical disc (7), and the elastic shaft (2) to be tested is fixedly connected with the planar disc (6) and is movably connected with the conical cylindrical disc (7); a fiber bragg grating strain gauge (5) connected with an circulator (4) through an optical fiber is stuck on the elastic shaft (2) to be tested, and torque is applied to the elastic shaft (2) to be tested through rotation of an external motor;

3) The ASE broadband light source (1) inputs an optical signal from one surface of the conical cylindrical disc (7) through a first incident optical fiber collimator (10), outputs the optical signal from a second light output port (14) of the planar disc (6) after multiple reflections between the planar disc (6) and the conical cylindrical disc (7), and enters the circulator (4) through the collimator (8) and the optical fiber, and then enters the fiber grating strain gauge (5) through the circulator (4);

4) Narrow-band light with central wavelength reflected by the fiber bragg grating strain gauge (5) is incident to the conical cylindrical disk (7) again through the circulator (4), the collimator (9) and the second incident light port (15) of the plane disk (6), and finally is output to the fiber bragg grating demodulator (3) from the first emergent fiber collimator (11) connected to the first emergent light port (12) of the conical cylindrical disk (7) after multiple reflections, and the current torque value is obtained through the fiber bragg grating demodulator (3).