CN101191751A

CN101191751A - Torque optical fiber sensor

Info

Publication number: CN101191751A
Application number: CNA2007101794713A
Authority: CN
Inventors: 江毅; 张佛健
Original assignee: Beijing Institute of Technology BIT
Current assignee: Beijing Institute of Technology BIT
Priority date: 2007-12-13
Filing date: 2007-12-13
Publication date: 2008-06-04
Anticipated expiration: 2027-12-13
Also published as: CN100587433C

Abstract

The invention relates to a novel torque optical fiber sensor and belongs to the test technology and optical fiber sensor field. The invention adopts a long-period optical fiber grating or a fused-tapered optical fiber as a measuring element; when the long-period optical fiber grating or the fused-tapered optical fiber is acted by the torque, the period of the long-period optical fiber grating or the optical intensity or the spectrum of the fused-tapered optical fiber can be changed, thereby measuring the torque value. The sensor is formed by a guiding optical fiber, a torsion rod (2), a torsion rod (3), a long-period optical fiber grating or a fused-tapered optical fiber (5), and a spring (4), wherein, two torsion rods (2) and ( 3) are connected by the spring (4) and can relatively be rotated. The long-period optical fiber grating or the fused-tapered optical fiber which are used for sensing are respectively fixed on the torsion rod (2) and the torsion rod (3). In addition, one torsion rod of the torque sensor is provided with a magnet which can form an optical fiber revolution sensor based on the torque measurement with a opposite polarity magnet which is arranged on a rotary mechanism.

Description

A kind of torque optical fiber sensor

Technical field

The invention belongs to measuring technology and Fibre Optical Sensor field, particularly a kind of design of novel torque optical fiber sensor and the scheme that realizes this design concept.

Background technology

In machine driven system, moment of torsion is one of typical machine amount of reflection production equipment system performance, and torque measurement and analysis are to guarantee that various productions and utility appliance safety normally moves, and save the energy, improve the important means of system effectiveness.The real-time of accuracy, torque monitoring and the control of raising torque measurement and the reliability of moment of torsion anomaly analysis are the important means that the minimizing accident takes place, production is normally carried out.

Along with the development of progress of science and technology and production, the torque measurement technology has wide application prospect.Simultaneously, the monitoring to moment of torsion has also proposed more and more higher requirement: turn to dynamic online detection by static test; Turn to direct measurement by indirect measurement; Turn to multi-functionally by single function, comprise self compensation, correction certainly, self-adaptation, self diagnosis, long-range setting, combinations of states, information stores and memory; The microminiaturization of requirement system, digitizing, intellectuality, virtual and networked; Require the detection of moment of torsion to combine, reach rotating speed, moment of torsion, power Output Optimization configuration with the control of propulsion system.

Present torque sensor mainly contains strain-type, the magnetoelectricity phase type, and photo-electrics etc. are several.They exist palpus dedicated elas-tic axle, and install and want two shaft couplings, complex structure, elastic shaft torsional strain amount is little, influences shortcomings such as sensitivity.In addition, in Design of Torque Sensor, main problem is the manufacturing of sensitive element, selects, and installs etc.Usually used torque sensor adopts the piezoelectric quartz wafer as measuring sensor, and the required piezoelectric quartz number of wafers of this sensor is many, and the height of wafer and the flatness of surface of contact, roughness require quite strict, and difficulty of processing is big, the technological requirement height.

Summary of the invention

The objective of the invention is to overcome test trouble in the traditional measurement method, the defective that complexity, degree of accuracy are not high, invent a kind of new optical fiber torque measuring method and new sensor, make measuring operation easy, cost is low, precision improves, and measurement range enlarges, and anti-electromagnetic interference (EMI).This method has characteristics such as high measurement accuracy, superior full photosensitiveness, insulativity, explosion-proof, anti-electromagnetic interference (EMI), heat-resisting quantity.Be suitable under the high temperature and explosion danger arranged and the kinematic train dynamic characteristic measuring of big machinery under the rugged surroundings such as strong electromagnetic is arranged.

The technical solution adopted in the present invention is as follows:

The present invention comprises guide optic fibre, two torsion bars, one section sensor fibre and a spring.Be connected by spring between two torsion bars; Sensor fibre passes through the axis of two torsion bars, and is separately fixed at the end of two torsion bars.Wherein, two torsion bars connect by spring.The effect that spring plays is not only the connection effect, and it can also realize reset response, and promptly when not relatively rotating between two torsion bars, spring can guarantee that two torsion bars are at initial position.In addition, after being applied to moment of torsion on the torsion bar and removing, spring can guarantee that torsion bar gets back to initial position, realizes duplicate measurements.

In this sensor construction, when torsion bar is subjected to the effect of power and when rotating, the effect that sensor fibre also is subjected to moment of torsion produces distortion.The light intensity or the wavelength variations of its transmitted spectrum of sensor fibre distortion back are relevant with the size of moment of torsion.By measuring the light intensity or the wavelength variations of sensor fibre transmitted spectrum, just can obtain torque value.

The present invention compared with prior art has the following advantages:

1. the employing all optical fibre structure can effectively prevent electromagnetic interference (EMI), and can be used in the dangerous working environment;

2. measuring sensor adopts long period fiber grating or fused biconical taper optical fiber, utilizes the light intensity or the wavelength variations of its transmitted spectrum of sensor fibre distortion back to measure moment of torsion, can realize high-acruracy survey;

3. this scenario-frame is simple, installs easily, and more common torque sensor can have lower cost;

4. this scheme can realize distributed measurement, and that this is traditional sensor is not available.

Description of drawings

Fig. 1 is a structural principle synoptic diagram of the present invention;

Fig. 2 is a rotating speed torque measurement embodiment synoptic diagram;

Among the figure: 1-optical fiber, 2, the 3-torsion bar, 4-spring, 5-long period fiber grating or melting cone fiber, 6, the 7-permanent magnet, the tested rotary body of 8-, 9-light source, 10-detector.

Embodiment

Below in conjunction with accompanying drawing and embodiment the present invention is described in further detail:

Embodiment

A kind of novel torque optical fiber sensor of the present invention comprises 1, two torsion bar of guide

optic fibre

2,3, long period fiber grating or melting cone fiber 5, spring 4.Torsion bar 2 is connected by spring 4 with torsion bar 3, and sensor fibre passes through the axis of two torsion bars, and is separately fixed at the end of two torsion bars.Wherein, two torsion bars connect by spring.The effect that spring plays is not only the connection effect, and it can also realize reset response, and promptly when not relatively rotating between two torsion bars, spring can guarantee that two torsion bars are in initial position.See Fig. 1.，

In the embodiment shown in Figure 2, after the light that light source 9 sends enters optical fiber 1,, received by photo-detector 10 by sensor fibre 5.A permanent magnet 6 is installed in the end of torsion bar 3, an opposite polarity permanent magnet 7 also is installed in the outside of tested rotary body 8.When rotary body 8 does not rotate, do not have relative displacement between the

permanent magnet

6 and 7, so torsion bar 3 positions do not change yet.Sensor fibre 5 is not subjected to torsional interaction in this case, so detector 10 receives not variation of transmitted spectrum;

When object 8 rotates, drive magnet 7 simultaneously, magnet 6 is produced periodic attractive force, periodically rotate thereby drive torsion bar 3.Torsion bar 3 periodical rotation produce periodic change in torque, thereby sensor fibre 5 is subjected to periodic torsional interaction.This periodic torsional interaction makes and is modulated by the light intensity or the wavelength of sensor fibre.Can receive the spectrum of modulating through change in torque by photo-detector 10.By measuring the cycle that sensor fibre 5 transmitted spectrums change, just can measure rotating speed.

By Fig. 1, Fig. 2 adopts this sensor construction as can be seen, and the light path of optical fiber seals fully, have high sensitivity, anti-electromagnetic interference (EMI), corrosion-resistant, the explosion-proof characteristics such as not disturbing tested scene that reach, be more suitable under rugged surroundings such as strong electromagnetic, Korrosionsmedium and pollution, measuring; In addition, compare traditional torque sensor, adopt long period fiber grating or melting cone fiber can reach higher precision and scope as measuring sensor, and simple in structure, cost is low.

Claims

1. a torque optical fiber sensor comprises guide optic fibre (1), two torsion bars (2), (3), and long period fiber grating or melting cone fiber (5), spring (4) is characterized in that: be connected by spring (4) between described two torsion bars (2), (3); Long period fiber grating or melting cone fiber (5) pass through the axis of two torsion bars (2), (3), and are separately fixed at the end of two torsion bars (2), (3); Spring plays and connects and reset response, and guarantees do not having do not have relative displacement between two moments of torsion (2), (3) under the external force effect; After being applied to moment of torsion on the torsion bar and removing, spring can guarantee that torsion bar gets back to initial position, realizes duplicate measurements.

2. a kind of torque optical fiber sensor as claimed in claim 1 is characterized in that: the melting cone fiber in this sensor (5) is to form by the single-mode fiber fused biconical taper, the diameter of its covering and fibre core along fiber axis to all being tapered.

3. a kind of optical fiber speed probe based on this torque measurement principle as claimed in claim 1 is characterized in that: go up at a torsion bar (3) magnet (6) is installed, go up at measured rotating mechanism (8) the opposite polarity magnet of another piece (7) is installed; The moving circle of rotating mechanism (8) revolution drives signal of torque sensor output.

4. a kind of torque optical fiber sensor as claimed in claim 1 is characterized in that: in this sensor construction, when torsion bar is subjected to the effect of power and when rotating, the effect that sensor fibre also is subjected to moment of torsion produces distortion; The light intensity or the wavelength variations of its transmitted spectrum of sensor fibre distortion back are relevant with the size of moment of torsion; By measuring the light intensity or the wavelength variations of sensor fibre transmitted spectrum, obtain torque value.