CN101858805B - Torque measuring method based on annular space array - Google Patents

Abstract

The invention relates to a torque measuring method based on an annular space array, in particular to a method for measuring a dynamic torque of a mechanical rotary shaft under extreme environment. The method comprises the following steps of: arranging two annular space array sensors on the mechanical rotary shaft; measuring sine signals which are outputted by the two sensors and are proportional to the annular displacement; preprocessing, collecting, filtering, shaping and demodulating the sine signals, and then calculating the phase difference between the two signals; solving the torsion angle; and measuring the torque value by utilizing the relationship of the torsion angle and the torque. The invention can realize that the dynamic torque of the mechanical rotary shaft under extreme environment is measured and the measuring condition is free from the limitation of the outside environment, has simple installation and high measuring precision, and is suitable for measuring the dynamic torque of the mechanical rotary shaft under extreme environments of water turbines, geological exploration and the like.

Description

Torque measuring method based on annular space array

Technical field

The invention belongs to sensing and measure the control field, be specifically related to the measuring method of the mechanical rotating shaft dynamic torque under a kind of extreme environment.

Background technology

From the physics and the mechanics of materials, torque measuring method can be divided into TRANSFER METHOD, balance force method and energy conversion method three major types.In these three kinds of torque measuring methods, the method that TRANSFER METHOD utilizes moment of torsion to make elastic shaft produce torsional deflection is measured its moment of torsion, and principle is simple, and instrument is light, uses comparatively extensive at present.But at present still there is not effective detection method at the torque measurement of mechanical rotation axle under the extreme environments such as thump, high temperature, burn into vibration be big.

University Of Chongqing's design " a kind of read head of ring type spatial array torque sensor " comprises read head housing 1 and shape of a hoof armature core 10.As shown in Figure 1-Figure 3, read head housing 1 is formed by connecting by screw etc. at pin-and-hole 7 places by two parts symmetrical; Each symmetric part can be divided into shell 3 and matrix inner casing 4, and trapezoidal skewed slot 9 is arranged on inner casing 4 sidewalls, and inside and outside shell is by the machine-shaping of duralumin, hard alumin ium alloy disposable integral.Two antimeric inner casings 4 are formed circular arc passage 6, and described passage 6 is used to be nested in the annular space array outside, makes the read head housing to do complete circular motion along annular space array; Two symmetric part shells 3 are formed cavity 5.

Place shape of a hoof armature cores 10 in the described cavity 5, armature core end 12 is thinner, and its thickness is 1mm, mainly be for read head when relatively moving with annular space array, can play the effect of scanning to the magnetic steel ball.The trapezoidal skewed slot 11 on the shell side wall can be put in armature core end 12, to realize combining closely of read head housing 1 and shape of a hoof armature core 10, improves the sealing of read head.

As shown in Figure 4, be wound with two groups of coils 11 on the shape of a hoof armature core 10, wherein one group is drive coil, is input as exciting current; Another group is output as corresponding induced voltage signal for inductive coil.

As shown in Figure 5, shape of a hoof armature core 10 places the cavity 5 of read head housing 1, and the top of read head housing 1 is by loam cake 2, carries out sealing and fixing at pin-and-hole 8 places by screw etc.Whole read head seals with plastic cement.During use, the circular arc passage 6 of described read head is nested in the annular space array outside, and read head is fixed, to guarantee that the circular arc passage 6 and the gap on annular space array surface are 0.2mm by support.Mutual inductance principle between drive coil and the inductive coil is:

When exciting current is sinusoidal form stable and its angular frequency when being w, the mutual voltage of available phasor representation inductive coil

For:

${\stackrel{\·}{U}}_{21}=\mathrm{jw}{M}_0{\stackrel{\·}{I}}_1---\left(1\right)$

In the formula, M ₀The coefficient of mutual inductance of representing two coils,

The mutual inductance electric current of expression inductive coil.

When the phasor of driving voltage correspondence is

The equivalent resistance of drive coil is r ₁, equivalent inductance is respectively L ₁, then

${\stackrel{\&CenterDot;}{I}}_1={\stackrel{\&CenterDot;}{U}}_1/({\mathrm{<figure-callout\; id="1"\; label="r"\; filenames="HSA00000156635400011.png,HSA00000156635400023.png"\; state="\{\{state\}\}">r</figure-callout>}}_1+\mathrm{jw}{L}_1)---\left(2\right)$

${\stackrel{\&CenterDot;}{U}}_{21}=\mathrm{jw}{M}_0{\stackrel{\&CenterDot;}{U}}_1/({\mathrm{<figure-callout\; id="1"\; label="r"\; filenames="HSA00000156635400011.png,HSA00000156635400023.png"\; state="\{\{state\}\}">r</figure-callout>}}_1+\mathrm{jw}{L}_1)---\left(3\right)$

The mutual voltage of inductive coil then

Effective value be:

$U_{21}=w{M}_0{\mathrm{<figure-callout\; id="1"\; label="U"\; filenames="HSA00000156635400011.png,HSA00000156635400023.png"\; state="\{\{state\}\}">U</figure-callout>}}_1/{({\mathrm{<figure-callout\; id="1"\; label="r"\; filenames="HSA00000156635400011.png,HSA00000156635400023.png"\; state="\{\{state\}\}">r</figure-callout>}}_1^2+w^2{\mathrm{<figure-callout\; id="1"\; label="L"\; filenames="HSA00000156635400011.png,HSA00000156635400023.png"\; state="\{\{state\}\}">L</figure-callout>}}_1^2)}^{1/2}=k_1{M}_0{U}_1---\left(4\right)$

In the formula

Be constant.Therefore, the inductive coil output voltage amplitude is proportional to the coefficient of mutual inductance M between two coils ₀, and coefficient of mutual inductance M ₀Relevant with the character of magnetic medium.In the present invention, coefficient of mutual inductance M ₀The active volume of the magnetic steel ball that is enclosed with coil is relevant.Because this active volume is periodically variable, so coefficient of mutual inductance also should be the cycle variation.

When coil is x with respect to the displacement of annular space array, and the centre of sphere of establishing a certain magnetic steel ball is 0 point, this moment pairing coefficient of mutual inductance M ₀Maximum can be expressed as:

M ₀＝k ₂[cos(2πxD)+A] (5)

D is the diameter of magnetic steel ball in the formula, k ₂Be constant, A is the DC component that coefficient of mutual inductance produces, k ₂A represents the intrinsic coefficient of mutual inductance between the coil.

When to the added voltage u of drive coil ₁For:

u ₁＝Usin(wt) (6)

The voltage u that responds to of inductive coil then ₂For:

u ₂＝k ₁k ₂U[cos(2πx/D)+A]sin(wt+θ)＝kU[cos(2πx/D)+A]sin(wt+θ) (7)

Wherein, k=k ₁k ₂Be scale-up factor, θ is intrinsic the differing between induced voltage and the driving voltage.Hence one can see that, and the amplitude of induced voltage is subjected to the modulation of ring-like displacement x, and induced voltage signal is carried out demodulation, can obtain the variable quantity of ring-like displacement, thereby realize the conversion of torque information to electric signal.

Summary of the invention

The dynamic torque that the present invention is directed under the extreme environment is measured the present situation of still not having effective detection method, described torque sensor read head is nested in the annular space array outside, constitute ring type spatial array torque sensor, propose based on the dynamic torque measuring method under the annular space array sensor measurement extreme environment.

Described annular space array is made up of the ring-like non-magnetic stainless steel pipe of a closure and the magnetic steel ball of some, the single tight arrangement in pipe of magnetic steel ball; The size of closed ring-like non-magnetic stainless steel pipe is decided according to the diameter of tested mechanical rotating shaft.During installation, the ring-like non-magnetic stainless steel pipe of described closure is nested on the tested mechanical rotating shaft, and by equally distributed four through holes on the steel pipe, with fixing annular space array such as screw, annular space array and mechanical rotating shaft is rotated together.

Technical scheme of the present invention is as follows:

Described ring type spatial array torque sensor is installed on the mechanical rotating shaft with a determining deviation, and the reference position of the read head of two sensors on the ring-like array in space is all identical.Be the sensor load energizing current, when mechanical rotating shaft produces torsional interaction, measure two sinusoidal signals that are directly proportional with ring-like displacement that sensor is exported, after described sinusoidal signal carried out pre-service, collection, filter shape, demodulation, calculate the phase differential between two signals, solve torsion angle, thereby utilize the relation of torsion angle and moment of torsion, measure torque value.

The present invention can realize the measurement of mechanical rotating shaft dynamic torque under the extreme environment, and measuring condition is not subjected to outside factors, installs simply, can be applicable to the mechanical rotating shaft torque measurement under the extreme environments such as the hydraulic turbine, geologic prospecting.Simultaneously, owing to directly adopt software processes output electric signal, the error that " number-Mo " conversion that can effectively avoid the circuit common processing to bring causes, measuring accuracy height.

Description of drawings

The front schematic view of Fig. 1 " a kind of read head of ring type spatial array torque sensor " read head shell structure;

The A-A sectional view of Fig. 2 " a kind of read head of ring type spatial array torque sensor " read head shell structure;

The B-B sectional view of Fig. 3 " a kind of read head of ring type spatial array torque sensor " read head shell structure;

The front schematic view of Fig. 4 " a kind of read head of ring type spatial array torque sensor " shape of a hoof armature core;

Fig. 5 " a kind of read head of ring type spatial array torque sensor " read head one-piece construction synoptic diagram;

Torch measuring system structural representation among Fig. 6 the present invention;

Fig. 7 measuring method schematic flow sheet of the present invention.

Among the figure: 1-read head housing; 2-read head case top lid; The 3-shell; 4-matrix inner casing; The 5-cavity; 6-circular arc passage; 7-connects read head two antimeric pin-and-holes; 8-is the pin-and-hole of read head case top lid fixedly; Trapezoidal skewed slot in the 9-matrix on the shell side wall; 10-shape of a hoof armature core; 11-armature core coil; 12-armature core end.

Embodiment

Below in conjunction with accompanying drawing, further specify the specific embodiment of the present invention:

(1) sensor installation

As Fig. 6, two identical ring type spatial array torque sensors are fixed on the mechanical rotating shaft, and can rotate with mechanical rotating shaft; The spacing of two ring type spatial array torque sensors is L, and the reference position of corresponding readings head on annular space array is all identical separately, can not rotate with annular space array.When mechanical rotating shaft rotates, has relative displacement between the read head of each sensor and the corresponding annular space array.

(2) be the sensor load energizing current

As Fig. 6, be respectively two annular space array sensors and load on all four exciting current, export the sinusoidal voltage of certain frequency by the simulation output function of capture card, utilize current amplification circuit then, this on all four sinusoidal voltage is converted to the exciting current of the sinusoidal current of same frequency as two sensors.On all four pumping signal is provided for two annular space arrays, when not relatively rotating on two pairing sectional positions of annular space array on the mechanical rotating shaft, then the induced signal of two sensors is also in full accord; When two sections relatively rotated, when also promptly having torsion angle, establishing its torsion angle was φ, and to establish this moment corresponding angular velocity be w ₀, then read head with respect to the relative displacement of annular space array is in the two sensors:

x ₂＝Rw ₀t (9)

Wherein, R is the vertical range of annular space array outward flange to the mechanical rotating shaft axis.When the driving voltage that obtains when two annular space arrays was Usin (wt), according to the principle of work of read head, the induced voltage that can get two annular space array sensors was respectively:

$u_{22}=\mathrm{kU}[\cos \left(\frac{2\mathrm{\&pi;}}{D}{\mathrm{Rw}}_{0}t\right)+A]\sin (\mathrm{wt}+\mathrm{\&theta;})---\left(11\right)$

(3) signal of sensor is carried out pre-service

Because the signal that sensor is exported is more weak, need carry out processing and amplifying to it, and filtering part undesired signal.Therefore utilize amplifying circuit and filtering circuit that signal of sensor is carried out pre-service, after this handles, again its output voltage signal is offered follow-up acquisition system and gather.

(4) utilize data collecting card to gather voltage signal

Because whole torque measurement platform is realized in LabVIEW, therefore the output voltage of pretreated sensor need be collected and analyze in the computing machine and handle, and adopts NI data collecting card PCI-6221 to finish here.

(5) signal after gathering is carried out filter shape

Because signal that sensor is exported and nonideal sinusoidal signal, but the superposed signal of a plurality of harmonic componentss, its fundamental frequency is consistent with the frequency of exciting current.For the processing of follow-up signal, need carry out Filtering Processing to the signal of being gathered, only stay the bigger composition of amplitude in the harmonic components after the filtering, signal has just become comparatively desirable amplitude-modulated signal like this.

(6) signal behind the filter shape is carried out demodulation

Signal after step (5) is handled is an amplitude-modulated signal, needs further to its demodulation, and its demodulation method is to utilize software phase-lock loop, 90 ° of phase-shifters and low-pass filter to realize the synchronous demodulation of amplitude-modulated signal.It at first is the input end that modulated wave is added in phaselocked loop, when phase-locked loop operation during at lock-out state, phaselocked loop will be exported identical with carrier component frequency in the input signal, the voltage signal that the phase phasic difference is 90 °, the reference signal of synchronous detection will just be obtained then after 90 ° of this signal phase shifts, utilize the amplitude-modulated signal of this reference signal and input to multiply each other at last, again through just obtaining modulation signal after the low-pass filter filtering.

(7) phase differential of calculating two signals

In order to obtain the information of moment of torsion, also need further to calculate the phase differential of the two-way modulation signal after the demodulation.Its method is that two modulation signals are delivered to FFT Spectrum function among the LabVIEW of identical configuration respectively, obtains their amplitude-frequency and phase-frequency characteristic, respectively four outputs is delivered to the Unbundle family function among the LabVIEW then, extracts array from family.In order to calculate phase differential, earlier search has the call number of maximum amplitude element from the amplitude array of waveform, finds corresponding phase place then in the phase place array, and obtains the remainder after being divided by with 360, two waveforms are all carried out such processing, subtract each other and just obtain phase differential.

(8) according to the phase difference calculating moment of torsion

According to material mechanics principle, be that d, length are on the elastic shaft of L the time when moment of torsion M acts on diameter, axle will produce in elastic limit of materials and the linear torsion angle of moment of torsion

Have

In the formula, G is a shear modulus; I _PBeing polar moment of inertia, is the circular shaft of d to diameter, has:

I _P＝πd ⁴/32 (13)

So just have:

Formula (10) and the described induced voltage of formula (11), after the processing of step (3)-(7), the phase difference that obtains between two modulation signals is:

Torsion angle then

For:

Then can get moment of torsion by (14) formula and (16) formula is:

M＝Gd ⁴Dφ/(64RL) (17)

Wherein, G is a shear modulus, and d is the diameter of mechanical rotating shaft, and D is the diameter of magnetic steel ball in the annular space array, and R is the distance between the two sensors for the vertical range of annular space array outward flange to the mechanical rotating shaft axis, L.

(9) to result's correction and Show End Result

Because sensor positioning error can occur in installation process, this has certain error with regard to causing through the moment of torsion of gained behind the above several steps, but this error belongs to systematic error, needs to eliminate systematic error.Its method is to utilize the torque sensor of standard to calibrate, under the constant situation of load, utilized the repeatedly measured value of this sensor and standard torque sensor to compare before this, transformation load then, carry out duplicate measurements more relatively, so just obtain systematic error, utilize this systematic error that the moment of torsion in the step (8) is proofreaied and correct.

(10) exciting current of disconnection sensor

Measurement is finished, and after machinery quit work, the exciting current that disconnects sensor finished the measurement of moment of torsion.

Owing in the machine work process, need to monitor in real time its duty, need carry out online dynamic-torque measures, therefore need circulation step (4)～(9), after machinery quits work, the measurement of moment of torsion also can stop, stopping of torque measurement need be by step (10), and the exciting current that promptly disconnects sensor finishes the measurement of moment of torsion.

The embodiment that more than provides is in order to the practical application of explanation the present invention and it, and therefore makes those skilled in the art can make and use the present invention.But this only is a preferred embodiment, be not that the present invention is done any pro forma restriction, any one professional and technical personnel is in the scope that does not depart from technical solution of the present invention, and above technology of foundation and method do certain modification and the equivalent embodiment that is considered as equivalent variations is worked as in change.

Claims (1)

1. based on the torque measuring method of annular space array, it is characterized in that concrete steps are as follows:

(1) sensor installation

Two identical ring type spatial array torque sensors are fixed on the mechanical rotating shaft, and the spacing of two ring type spatial array torque sensors is L, and the reference position of corresponding readings head on annular space array is all identical separately;

(2) be the sensor load energizing current

Export the sinusoidal voltage U sin (wt) of certain frequency by the simulation output function of capture card, utilize current amplification circuit then, on all four described sinusoidal voltage is converted to the exciting current of the sinusoidal current of same frequency as two sensors, when two pairing cross sections of annular space array on the mechanical rotating shaft relatively rotated, the induced voltage of two annular space array sensors was respectively:

$U_{22}=\mathrm{kU}[\cos \left(\frac{2\mathrm{\&pi;}}{D}R{w}_{0}t\right)+A]\sin (\mathrm{wt}+\mathrm{\&theta;})---\left(2\right)$

Wherein: k is a scale-up factor, and A is the DC component that coefficient of mutual inductance produces, and D is the diameter of magnetic steel ball in the annular space array, and φ is a torsion angle, w ₀Be the mechanical rotating shaft rotational angular, R is the vertical range of annular space array outward flange to the mechanical rotating shaft axis;

(3) signal of sensor is carried out pre-service

Utilize amplifying circuit and filtering circuit that signal of sensor is carried out pre-service;

(4) utilize data collecting card to gather voltage signal

Utilize data collecting card, gather the output voltage of latter two sensor of pre-service;

(5) signal after gathering is carried out filter shape

Signal to described collection carries out Filtering Processing, only stays the bigger composition of amplitude in the harmonic components after the filtering;

(6) signal behind the filter shape is carried out demodulation

Utilize software phase-lock loop, 90 ° of phase-shifters and low-pass filter to realize the synchronous demodulation of amplitude-modulated signal; At first modulated wave is added in the input end of phaselocked loop, when phase-locked loop operation during at lock-out state, phaselocked loop will be exported identical with carrier component frequency in the input signal, the voltage signal that the phase phasic difference is 90 °, the reference signal of synchronous detection will just be obtained then after 90 ° of this signal phase shifts, utilize the amplitude-modulated signal of this reference signal and input to multiply each other at last, obtain modulation signal through just reducing after the low-pass filter filtering again;

(7) phase differential of calculating two signals

Two modulation signals are delivered to respectively in the FFT Spectrum function among the LabVIEW of identical configuration, obtained their amplitude-frequency and phase-frequency characteristic, respectively four outputs are delivered to the Unbundle family function among the LabVIEW then, from family, extract array;

Subsequently, search has the call number of maximum amplitude element from the amplitude array of waveform, finds in the phase place array corresponding phase place, and obtains the remainder after being divided by with 360, and two waveforms are all carried out such processing, subtracts each other just to obtain phase differential;

(8) according to the phase difference calculating moment of torsion

According to material mechanics principle:

Wherein, M is that to act on diameter be that d, length are the torque value that produces on the elastic shaft of L the time,

For elastic shaft will produce in elastic limit of materials and the linear torsion angle of moment of torsion;

After formula (1) and formula (2) were handled through step (3)-(7), the phase difference that obtains between two modulation signals was:

Torsion angle then For:

Then can get moment of torsion by formula (3) and formula (5) is:

M＝Gd ⁴Dφ/(64RL) (6)

Wherein, G is a shear modulus, and d is the diameter of mechanical rotating shaft, and L is the distance between the two sensors;

(9) to result's correction and Show End Result

Utilize the torque sensor of standard to calibrate, earlier under the constant situation of load, utilize the repeatedly measured value of described annular space array sensor and standard torque sensor to compare, transformation load carries out duplicate measurements relatively more then, tries to achieve system errors for measurement; Utilize this systematic error that the moment of torsion in the step (8) is proofreaied and correct;

(10) exciting current of disconnection sensor

Measurement is finished, and the exciting current that disconnects sensor finishes the measurement of moment of torsion.

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