CN104836542A - Pre-amplifier for measuring wind-tunnel balance signal and calibration measurement method - Google Patents

Abstract

The invention discloses a pre-amplifier for measuring a wind-tunnel balance signal. The wind-tunnel balance signal is generated on the basis of a strain balance arranged in a wind tunnel. The pre-amplifier comprises an amplification circuit board and a through circuit board, wherein the amplification circuit board is provided with eight signal amplification channels; each channel is provided with a conditioning circuit for amplifying a measurement signal; the through circuit board is provided with eight signal through channels; and each of the amplification circuit board and the through circuit board is further provided with an input connector P1 for being connected to the strain balance and an output connector P2 for being connected to a data acquisition terminal. The pre-amplifier for measuring the wind-tunnel balance signal has the advantages of high measurement accuracy, high anti-interference capability and higher safety coefficient. The invention also provides a calibration method for the pre-amplifier. Through adoption of the calibration method, the measurement accuracy of a later data acquisition terminal is increased.

Description

A kind of preamplifier for wind-tunnel balance signal measurement and calibration measurement method

Technical field

The present invention relates to a kind of amplifier that wind-tunnel balance signal measurement is used.More particularly, the present invention relates to a kind of preamplifier for wind-tunnel balance signal measurement.

Background technology

In current prior art book, the method and apparatus that wind tunnel test balance signal measurement adopts mainly contains two kinds, wherein one adopts preamplifier to measure in conjunction with Back end data acquisition terminal, another be directly realize the amplification of signal by Back end data acquisition terminal, filtering, collection measure.

But existing measure setup certainty of measurement is not high, antijamming capability is not strong.Along with the development of national wind tunnel test high, precision and frontier technology, to wind tunnel test test function and performance requirement more and more higher, also more and more higher to the requirement of testing equipment, means of testing in the past can not meet the requirement of high-performance wind tunnel test far away, has not caught up with science and technology developing steps fast.

Summary of the invention

An object of the present invention is to solve at least the problems referred to above and/or defect, and the advantage will illustrated at least is below provided.

A further object of the invention is to provide provides a kind of preamplifier for wind-tunnel balance signal measurement, and it makes to have the advantage that certainty of measurement is high, antijamming capability strong, coefficient of safety is higher.

A further object of the invention is to provide a kind of calibration steps of preamplifier, improves the certainty of measurement of later data acquisition terminal.

A further object of the invention is measured the method for measurement of wind-tunnel balance signal, and it is based on the calibration to each amplifying signal passage of preamplifier, to realize the more accurate object of final measurement.

In order to realize, according to these objects of the present invention and other advantage, providing a kind of preamplifier for wind-tunnel balance signal measurement, described wind-tunnel balance signal produces based on the strain balance be arranged in wind-tunnel, comprising:

Magnification circuit plate, it has 8 signal amplification channels, and each passage is provided with the modulate circuit amplified described measuring-signal;

Direct circuit plate, it has 8 signal put-through channels;

Wherein, described magnification circuit plate, direct circuit plate are also respectively arranged with the input connector P1 for being connected to strain balance, for being connected to the out connector P2 of data collection station.

Preferably, wherein, described modulate circuit comprises:

Input amplifying circuit, it is connected with the signal output part of described strain balance, after carrying out High frequency filter amplification to the strain balance voltage signal received, export single-ended voltage signal;

Low pass active filter circuit, it is connected with described input amplifying circuit, in order to reduce rear output to the measurement noises in the single-ended voltage signal received;

Differential output circuit, it is connected with described low pass active filter circuit, exports in order to the single-ended voltage signal after noise reduction process received is carried out twice amplification and converts differential signal to.

Preferably, wherein, described input amplifying circuit comprises instrument amplifier and is electrically connected to the rc filter circuit of its input, the input of described rc filter circuit is connected with the signal output part of strain balance, and described instrument amplifier forms by monolithic die U1 and gain resistor Rg the amplifying circuit that gain is 100.

Preferably, wherein, the input of described low pass active filter circuit is connected with the output of described instrument amplifier, and described low pass active filter circuit is the quadravalence Butterworth LPF of 10Hz, described quadravalence Butterworth low pass device is made up of the second order Butterworth low pass wave circuit of two series connection.

Preferably, wherein, described differential output circuit is made up of two U3A of operational amplifier being in the same way connected in parallel to described low-pass filter circuit output and reverse operational amplifier U3B, with the amplification of the conversion and twice that realize single-ended-to-difference.

Preferably, wherein, described strain balance is the full-bridge circuit that the strain balance of six components is formed, signal output part, the feeder ear of described full-bridge circuit are connected with magnification circuit plate, direct circuit board communications respectively by input connector P1, described signal output part comprises anode Vin+ to each passage output difference divided voltage signal and negative terminal VIN-, and described feeder ear comprises anode VCC and the negative terminal AGND of full-bridge circuit.

Preferably, wherein, the inwall of described input connector P1, out connector P2 link has two different grooves of spacing distance, wherein

Described input connector P1 provides input interface for strain balance signal measurement, it comprises the second input connector Xs2 that the first input connector Xs1 of being connected with magnification circuit plate and direct circuit plate connect, the each passage input pin of tested balance signal is set in it respectively, the level bridge pressure input of tested sky, feedback pin and grounding pin, be also provided with in described second input connector Xs2 and amplify power supply input pin;

Described out connector P2 provides signal output interface for data collection station, it comprises amplifying end out connector XS3 and leading directly to holds input connector Xs4, each channel signal output pin is respectively arranged with, the input of tested sky level bridge pressure, feedback pin and grounding pin in it.

Preferably, wherein, also comprise and being arranged on outside described magnification circuit plate, direct circuit plate to realize the insulation division board of itself and other mechanism's electrical isolation.

A calibration steps for each signal amplification channel of preamplifier, comprising:

Step one, at the input connector end of described magnification circuit plate to each passage input i the simulated strain balance signal Ei in described 8 signal amplification channels, then export i magnitude of voltage X after each signal amplification channel amplification at out connector end _i, wherein said simulated strain balance signal Ei is magnitude of voltage at the direct current signal of-50 ~ 50 millivolts;

Step 2, described data collection station receive i the magnitude of voltage X that each signal amplification channel exports _i, and the calibration parameter of each signal amplification channel is calculated based on i the simulated strain balance signal Ei that each signal amplification channel inputs, described calibration parameter is obtained by following formula:

$k=\frac{\underset{i=1}{\overset{11}{\mathrm{\Σ}}}{x}_i\underset{i=1}{\overset{11}{\mathrm{\Σ}}}{E}_i-11\×\underset{i=1}{\overset{11}{\mathrm{\Σ}}}{x}_i{E}_i}{{\left(\underset{i=1}{\overset{11}{\mathrm{\Σ}}}{E}_i\right)}^2-11\underset{i=1}{\overset{11}{\mathrm{\Σ}}}{E_i}^2}$

$b=\frac{\underset{i=1}{\overset{11}{\mathrm{\Σ}}}{x}_i{E}_i\underset{i=1}{\overset{11}{\mathrm{\Σ}}}{E}_i-\underset{i=1}{\overset{11}{\mathrm{\Σ}}}{x}_i\underset{i=1}{\overset{11}{\mathrm{\Σ}}}{E_i}^2}{{\left(\underset{i=1}{\overset{11}{\mathrm{\Σ}}}{E}_i\right)}^2-11\underset{i=1}{\overset{11}{\mathrm{\Σ}}}{E_i}^2}$

Object of the present invention can also measure wind-tunnel balance signal method further by the preamplifier after calibration realizes, and comprising:

Step one, input strain balance signal by wind-tunnel balance to 8 signal amplification channels of magnification circuit plate simultaneously;

Each passage of step 2, described magnification circuit plate, based on the strain balance signal received, after carrying out filter and amplification, exports the voltage signal Vout after amplifying by described modulate circuit _j;

Step 3, described data collection station receive the voltage signal Vout of each signal amplification channel output of magnification circuit plate by described out connector _j; And based on each signal amplification channel calibration parameter k and b, adopt following formulae discovery to go out the voltage signal Vin of strain balance output _j,

Vin _j＝(Vout _j-b _j)/k _j

Wherein, j is 8 signal amplification channels of 0-7, b _jand k _jbe respectively slope and the intercept of each amplifying signal passage fitting a straight line.The present invention at least comprises following beneficial effect: one, preamplifier in the present invention, because it is integrated with magnification circuit plate and direct circuit plate on a device, connect owing to have employed 8 passage direct circuits, this device is made both to have had the feature of the compatible old acquisition system in rear end, synchronous signal definition defines identical with amplification channel, is conducive in sky flush end and collection terminal and magnification circuit plate common cable like this; Because it realizes a device, there is the function of amplifying and leading directly to simultaneously, there is compatible good beneficial effect.

They are two years old, the present invention is when applying this preamplifier and carrying out wind tunnel test measurement, because its modulate circuit have employed high-precision amplification circuit, filter circuit and differential output circuit, adopt fixing multiplication factor, decrease the complexity of circuit, make measurement have very high certainty of measurement, measure feasibility and stability, measurement anti-interference and transmission anti-interference.

Part is embodied by explanation below by other advantage of the present invention, target and feature, part also will by research and practice of the present invention by those skilled in the art is understood.

Accompanying drawing explanation

Fig. 1 is the structural representation of preamplifier in one embodiment of the present of invention;

Fig. 2 is the structural representation of modulate circuit in one embodiment of the present of invention;

Fig. 3 is the structural representation of strain balance in an alternative embodiment of the invention;

Fig. 4 is the structural representation of input connector in an alternative embodiment of the invention;

Fig. 5 is the structural representation of out connector in an alternative embodiment of the invention;

Fig. 6 is the structural representation of input, out connector pin groove in an alternative embodiment of the invention.

Embodiment

Below in conjunction with accompanying drawing, the present invention is described in further detail, can implement according to this with reference to specification word to make those skilled in the art.

Should be appreciated that used hereinly such as " to have ", other element one or more do not allotted in " comprising " and " comprising " term or the existence of its combination or interpolation.

Fig. 1 shows the implementation according to a kind of preamplifier for wind-tunnel balance signal measurement of the present invention, and described wind-tunnel balance signal produces based on the strain balance be arranged in wind-tunnel, comprising:

Magnification circuit plate 1, it has 8 signal amplification channels, and each passage is provided with the modulate circuit 110 amplified described measuring-signal, in its each amplifying signal passage, the circuit theory of modulate circuit is the same with structure, by 200 times of fixing multiplication factor circuit, 4 rank Butterworth LPF, differential output circuit, power circuit composition.Its 200 times fixing multiplication factor circuit adopt the superhigh precision of state-of-the-art technology, the more instrument amplifier of low drifting to realize 100 times of amplifications, arrange multiplication factor by arranging gain resistor, resistance also adopts the precision of 0.02%, the precision resister of 20ppm temperature drift; Its 4 rank Butterworth LPF circuit adopts precision resister and high accuracy dual operational amplifier to realize, filter cutoff frequency 10H (-3dB); Its differential output circuit also adopts high accuracy dual operational amplifier to form, and a road realizes following, and a road realizes anti-phase, so just forms difference output, realizes 2 times of amplifications simultaneously, and whole circuit just realizes 200 times of amplifications; Externally fed got by its power circuit, by giving the power supply circuits of balance strain bridge and the bridge pressure feedback circuit for gathering compensation after filtering.Described magnification circuit plate is used for providing bridge pressure for strain balance, and feed back strain balance bridge and be pressed onto data collection station, finally carry out A/D conversion by giving data collection station after the amplification of strain balance signal, filtering, simultaneously when carrying out wind tunnel test and measuring, owing to have employed high-precision amplification circuit, filter circuit and differential output circuit, adopt fixing multiplication factor, decrease the complexity of circuit, make measurement have very high certainty of measurement, measure feasibility and stability, measurement anti-interference and transmission anti-interference;

Direct circuit plate 2, it has 8 signal put-through channels, described direct circuit plate is used for providing bridge pressure for strain balance, feedback strain balance bridge is pressed onto data collection station and carries out A/D conversion, 8 passage balance signals wherein are directly connected to out connector from circuit board trace by input connector, Back end data acquisition terminal is connected to finally by cable, also be balance strain bridge Power supply simultaneously, and the bridge pressure feedback circuit for gathering compensation, the compatible old data collection station system measured without preamplifier simultaneously, while this makes it remain the compatible former data collection station system features in rear end, its signal definition defines identical with amplification channel, it is made to be conducive in sky flush end and collection terminal common cable,

Wherein, described magnification circuit plate, direct circuit plate are also respectively arranged with the input connector P1 3 for being connected to strain balance, for being connected to the out connector P2 4 of data collection station, in order to further improve certainty of measurement, the stube cable of described out connector and data collection station adopts high-quality paired shield cable, to increase jamproof ability; When simultaneously described input connector P1, out connector P2 make front-end amplifier amplify with straight-through switching, only need connector plug cable being connected to corresponding amplification or straight-through function, simple; Wherein P1 measures input for strain balance and provides interface, for connecting the differential voltage signal that strain balance exports, connects the power supply of powering to strain balance, connects the balance power end of sky flush end feedback; Wherein P2 is the signal output part of signal regulating device, for connecting the differential output signal after conditioning, connects the power supply of this preamplifier, connects strain balance power supply, connects the balance power end of strain balance end feedback.Adopt in this scheme and make this preamplifier have good compatibility, certainty of measurement is high, measure and transmission the strong favourable part of antijamming capability and, this mode is a kind of explanation of preferred embodiments, but is not limited thereto.

In another kind of example, described modulate circuit 110 comprises:

Input amplifying circuit 120, it is connected with the signal output part of described strain balance, after carrying out High frequency filter amplification to the strain balance voltage signal received, export single-ended voltage signal;

Low pass active filter circuit 130, it is connected with described input amplifying circuit, in order to reduce rear output to the measurement noises in the single-ended voltage signal received;

Differential output circuit 140, it is connected with described low pass active filter circuit, exports in order to the single-ended voltage signal after noise reduction process received is carried out twice amplification and converts differential signal to.Also comprise protective circuit; power supply circuits adopt the magnification circuit plate of this scheme because adopting fixing multiplication factor; decrease the complexity of circuit, make measurement have very high certainty of measurement, measure feasibility and stability strong, measure and transmission strong interference immunity, favourable part that coefficient of safety is high.Further, this mode is a kind of explanation of preferred embodiments, but is not limited thereto.

As shown in Figure 2 in another kind of example, described input amplifying circuit comprises instrument amplifier 121 and is electrically connected to the rc filter circuit 122 of its input, the input of described rc filter circuit is connected with the signal output part of strain balance, and described instrument amplifier forms by monolithic die U1 123 and gain resistor Rg 124 amplifying circuit that gain is 100.Wherein U1 and Rg forms 100 times of amplifying circuits, and the input pickup resistance electric capacity of U1 forms rc filter circuit, filters the high fdrequency component in balance signal, and this part realizes Differential Input and exports the single-ended voltage signal after amplifying.Adopt this scheme to have multiplication factor to fix, the simple favourable part of circuit.Further, this mode is a kind of explanation of preferred embodiments, but is not limited thereto.

In another kind of example, the input of described low pass active filter circuit 130 is connected with the output of described instrument amplifier, and described low pass active filter circuit is the quadravalence Butterworth LPF of 10Hz, described quadravalence Butterworth low pass device is made up of the second order Butterworth low pass wave circuit 131 of two series connection.Adopt this scheme while single ended input Single-end output, reduce measurement noises, the favourable part be improved to make the certainty of measurement in its later stage.Further, this mode is a kind of explanation of preferred embodiments, but is not limited thereto.

In another kind of example, described differential output circuit 140 is made up of two U3A of operational amplifier in the same way 141 being connected in parallel to described low-pass filter circuit output and reverse operational amplifier U3B 142, with the amplification of the conversion and twice that realize single-ended-to-difference.Wherein U3A and U3B and peripheral circuit thereof carry out the change-over circuit of single-ended-to-difference, are just following respectively and are following with anti-phase, achieve 2 times of amplifications, the function of output difference divided voltage signal.Adopt this scheme to realize single ended input, difference output, realize the enlarging function that gain is 2, have circuit structure simple, the data acquisition end computational accuracy for the later stage improves significant help.Further, this mode is a kind of explanation of preferred embodiments, but is not limited thereto.

As shown in Figure 3, in another kind of example, described strain balance is the full-bridge circuit 5 that the strain balance of six components is formed, signal output part, the feeder ear of described full-bridge circuit are connected with magnification circuit plate, direct circuit board communications respectively by input connector P1, described signal output part comprises anode Vin+ to each passage output difference divided voltage signal and 51 negative terminal VIN-52, and described feeder ear comprises anode VCC 53 and the negative terminal AGND 54 of full-bridge circuit.Wherein, Vin+ and Vin-is anode and the negative terminal of a differential voltage signal passage output, and AGND is the common port of differential voltage signal output and the ground equipotential of balance passage power supply, is connected to the signal input part of signal regulating device during measurement; VCC and AGND be balance strain full-bridge feeder ear, VCC is anode, AGND be hold, 8 passages adopt same Power supply.During work, system is that balance passage is powered by this preamplifier, and when balance generation deformation, this passage exports the voltage that different deformation produces, and 8 passages work simultaneously, can realize 8 passage 6 COMPONENT BALANCE to the measurement of force and moment.Adopt the favourable part that this scheme is pointed by force, measurement effect is good.Further, this mode is a kind of explanation of preferred embodiments, but is not limited thereto.

As shown in Figure 4,5, in another kind of example, the inwall of described input connector P1, out connector P2 link has different two grooves 31,41 of spacing distance, it makes, when replacing or failture evacuation, I/O cable connector can be avoided to connect instead, wherein

Described input connector P1 provides input interface for strain balance signal measurement, it comprises the second input connector Xs233 that the first input connector Xs1 32 of being connected with magnification circuit plate and direct circuit plate connect, the each passage input pin 34 of tested balance signal is set in it respectively, the level bridge pressure input of tested sky, feedback pin 35 and grounding pin 36, be also provided with in described second input connector Xs2 and amplify power supply input pin;

As shown in Figure 6, described out connector P2 provides signal output interface for data collection station, it comprises amplifying end out connector XS3 42 and leading directly to holds input connector Xs4 43, each channel signal output pin 44 is respectively arranged with, the input of tested sky level bridge pressure, feedback pin 45 and grounding pin 46 in it.This scheme is adopted to have straight-through function and enlarging function switches simply, and the design of its connector Anti-misplug, make the favourable part that the coefficient of safety of product is improved.Further, this mode is a kind of explanation of preferred embodiments, but is not limited thereto.

In another kind of example; also comprise and being arranged on outside described magnification circuit plate, direct circuit plate to realize the insulation division board (not shown) of itself and other mechanism's electrical isolation; realized the isolation of test mechanism and wind-tunnel wall by the design of insulation division board, reach the object of crashproof safeguard protection.When in the mechanism that preamplifier is arranged near balance, the ground of preamplifier and mechanism are carried out electrical isolation, and be connected with preamplifier data collection station altogether is the largest, and the earth is connected with wind-tunnel wall, such mechanism and wind-tunnel wall just isolated.When applying this preamplifier and carrying out wind tunnel test measurement; owing to have employed the design of insulation division board; and this conditioning device shell both can shield to be connected to reduce to disturb with measuring system and made can design between mechanism and wind-tunnel wall hardware collision prevention device; when wind-tunnel wall and mechanism collide; feed back to whole TT&C system, system realizes safeguard protection by software and hardware.This scheme is adopted to have good stability, the favourable part that coefficient of safety is high.Further, this mode is a kind of explanation of preferred embodiments, but is not limited thereto.

The calibration steps of each signal amplification channel of the preamplifier in such scheme, comprising:

Step one, at the input connector end of described magnification circuit plate to each passage input i the simulated strain balance signal Ei in described 8 signal amplification channels, then export i magnitude of voltage X after each signal amplification channel amplification at out connector end _i, wherein said simulated strain balance signal Ei is magnitude of voltage at the direct current signal of-50 ~ 50 millivolts;

Step 2, described data collection station receive i the magnitude of voltage X that each signal amplification channel exports _i, and the calibration parameter of each signal amplification channel is calculated based on i the simulated strain balance signal Ei that each signal amplification channel inputs, described calibration parameter is obtained by following formula:

$k=\frac{\underset{i=1}{\overset{11}{\mathrm{\Σ}}}{x}_i\underset{i=1}{\overset{11}{\mathrm{\Σ}}}{E}_i-11\×\underset{i=1}{\overset{11}{\mathrm{\Σ}}}{x}_i{E}_i}{{\left(\underset{i=1}{\overset{11}{\mathrm{\Σ}}}{E}_i\right)}^2-11\underset{i=1}{\overset{11}{\mathrm{\Σ}}}{E_i}^2}$

$b=\frac{\underset{i=1}{\overset{11}{\mathrm{\Σ}}}{x}_i{E}_i\underset{i=1}{\overset{11}{\mathrm{\Σ}}}{E}_i-\underset{i=1}{\overset{11}{\mathrm{\Σ}}}{x}_i\underset{i=1}{\overset{11}{\mathrm{\Σ}}}{E_i}^2}{{\left(\underset{i=1}{\overset{11}{\mathrm{\Σ}}}{E}_i\right)}^2-11\underset{i=1}{\overset{11}{\mathrm{\Σ}}}{E_i}^2}$

Adopt this scheme due to by having carried out measurement and calibration to each amplifying signal passage of magnification circuit plate by the mode of line line matching, make the linear fit parameter of each passage more accurate, when adopting the output signal of preamplifier to strain balance after calibration to detect, because the linear fit parameter after its calibration participates in whole survey calculation, the certainty of measurement of whole like this wind tunnel test system will be further improved, wherein, its linear fit adopts least square method to carry out linear fit, preamplifier is made to have parameter accurate, the favourable part that Measurement sensibility is good.Further, this mode is a kind of explanation of preferred embodiments, but is not limited thereto.

Measured the method for wind-tunnel balance signal in such scheme by the preamplifier after calibration, comprising:

Step one, input strain balance signal by wind-tunnel balance to 8 signal amplification channels of magnification circuit plate simultaneously;

Each passage of step 2, described magnification circuit plate, based on the strain balance signal received, after carrying out filter and amplification, exports the voltage signal Vout after amplifying by described modulate circuit _j;

Step 3, described data collection station receive the voltage signal Vout of each signal amplification channel output of magnification circuit plate by described out connector _j; And based on each signal amplification channel calibration parameter k and b, adopt following formulae discovery to go out the voltage signal Vin of strain balance output _j,

Vin _j＝(Vout _j-b _j)/k _j

Wherein, j is 8 signal amplification channels of 0-7, b _jand k _jbe respectively slope and the intercept of each amplifying signal passage fitting a straight line.

Following table is calibration steps and the result of calculation of a passage, and wherein X is Vin, Y be Vout, L is nonlinearity erron.

Vin(X)	Vout(Y)	X*Y			Y after conversion	L
							-46.9909	-9414.40	442391.129	X's and square	0.075735	-9412.99989	-0.007001
-37.8581	-7586.55	287212.3686	The quadratic sum of X	9843.71	-7586.254174	-0.001479
							-28.5646	-5726.30	163569.469	X and	0.2752	-5727.36519	0.005326
-19.1085	-3835.60	73292.5626	Y and	-97.462	-3835.952899	0.001764
							-9.5717	-1928.04	18454.62047	X*Y and	1968938	-1928.398968	0.001795
-0.0003	-15.88	0.0047646	k	200.0203	-13.92433303	-0.009788
							9.5950	1908.00	18307.26	b	-13.8643	1905.330788	0.013346
19.1520	3818.00	73122.336	L (%) minimum value	-0.00979	3816.92513	0.005374
							28.6400	5714.63	163667.0032	L (%) maximum	0.013346	5714.718069	-0.000440
38.0452	7595.56	288974.5993	Gain error (%)	0.010168	7595.949324	-0.001947
							46.9371	9373.12	439947.0708			9374.510142	-0.006951

Nonlinearity erron and gain error are all very little as can be seen from the table, and precision is very high.Adopt this scheme, first described preamplifier is before measuring the output signal of strain balance, because each signal amplification channel of described magnification circuit plate has carried out measurement and calibration one by one, make the linear fit parameter of each signal amplification channel more accurate, described data collection station is based on the linear fit parameter of each signal amplification channel after calibration, voltage signal through calculating strain balance output is more accurate, thus improve the accuracy of whole measuring system, there is certainty of measurement high, the favourable part of good stability.Further, this mode is a kind of explanation of preferred embodiments, but is not limited thereto.

Here the number of devices illustrated and treatment scale are used to simplify explanation of the present invention.The application of preamplifier of the present invention, modifications and variations be will be readily apparent to persons skilled in the art.

As mentioned above, according to the present invention, one, preamplifier in the present invention, because it is integrated with magnification circuit plate and direct circuit plate on a device, connect owing to have employed 8 passage direct circuits, make this device both have the feature of the compatible old acquisition system in rear end, synchronous signal definition defines identical with amplification channel, is conducive in sky flush end and collection terminal and magnification circuit plate common cable like this; Because it realizes a device, there is the function of amplifying and leading directly to simultaneously, there is compatible good beneficial effect.

They are two years old, the present invention is when applying this preamplifier and carrying out wind tunnel test measurement, because its modulate circuit have employed high-precision amplification circuit, filter circuit and differential output circuit, adopt fixing multiplication factor, decrease the complexity of circuit, make measurement have very high certainty of measurement, measure feasibility and stability, measurement anti-interference and transmission anti-interference.

They are three years old, insulation division board in the present invention, it is when preamplifier is arranged in the mechanism near balance, the ground of preamplifier and mechanism are carried out electrical isolation, and be connected with the largest of signal condition data collection station altogether, and the earth is connected with wind-tunnel wall, such mechanism and wind-tunnel wall just achieve electrical isolation, described preamplifier shell not only can shield to be connected with measuring system and reduce to disturb but also make can design hardware collision prevention device between mechanism and wind-tunnel wall, when wind-tunnel wall and mechanism collide, feed back to whole TT&C system, system realizes safeguard protection by software and hardware.

They are four years old, input in the present invention, out connector, the Anti-misplug design of its interface, make preamplifier carry out straight-through switch with amplification time, only need connector plug input and output connector joint being connected to corresponding amplification or straight-through function, more simple, feasibility is higher.

They are five years old, in the present invention when applying this preamplifier and carrying out wind tunnel test measurement, carry out calibrating one by one to each amplifying signal passage of magnification circuit plate, make the parameter of each passage more accurate, and then the measurement result accuracy of carrying out when strain balance output signal is measured adopting this preamplifier is synchronously improved.

Although embodiment of the present invention are open as above, it is not restricted to listed in specification and execution mode utilization.It can be applied to the various field being applicable to this practicality completely.For those skilled in the art, can easily realize other amendment.Therefore do not deviating under the universal that claim and equivalency range limit, this practicality is not limited to specific details and illustrates here and the legend described.

Claims (10)

1., for a preamplifier for wind-tunnel balance signal measurement, described wind-tunnel balance signal produces based on the strain balance be arranged in wind-tunnel, it is characterized in that, comprising:

Magnification circuit plate, it has 8 signal amplification channels, and each passage is provided with the modulate circuit amplified described measuring-signal;

Direct circuit plate, it has 8 signal put-through channels;

Wherein, described magnification circuit plate, direct circuit plate are also respectively arranged with the input connector P1 for being connected to strain balance, for being connected to the out connector P2 of data collection station.

2., as claimed in claim 1 for the preamplifier of wind-tunnel balance signal measurement, it is characterized in that, described modulate circuit comprises:

Input amplifying circuit, it is connected with the signal output part of described strain balance, after carrying out High frequency filter amplification to the strain balance voltage signal received, export single-ended voltage signal;

Low pass active filter circuit, it is connected with described input amplifying circuit, in order to reduce rear output to the measurement noises in the single-ended voltage signal received;

Differential output circuit, it is connected with described low pass active filter circuit, exports in order to the single-ended voltage signal after noise reduction process received is carried out twice amplification and converts differential signal to.

3. as claimed in claim 2 for the preamplifier of wind-tunnel balance signal measurement, it is characterized in that, described input amplifying circuit comprises instrument amplifier and is electrically connected to the rc filter circuit of its input, the input of described rc filter circuit is connected with the signal output part of strain balance, and described instrument amplifier forms by monolithic die U1 and gain resistor Rg the amplifying circuit that gain is 100.

4. as claimed in claim 3 for the preamplifier of wind-tunnel balance signal measurement, it is characterized in that, the input of described low pass active filter circuit is connected with the output of described instrument amplifier, and described low pass active filter circuit is the quadravalence Butterworth LPF of 10Hz, described quadravalence Butterworth low pass device is made up of the second order Butterworth low pass wave circuit of two series connection.

5. as claimed in claim 4 for the preamplifier of wind-tunnel balance signal measurement, it is characterized in that, described differential output circuit is made up of two U3A of operational amplifier being in the same way connected in parallel to described low-pass filter circuit output and reverse operational amplifier U3B, with the amplification of the conversion and twice that realize single-ended-to-difference.

6. as claimed in claim 1 for the preamplifier of wind-tunnel balance signal measurement, it is characterized in that, described strain balance is the full-bridge circuit that the strain balance of six components is formed, signal output part, the feeder ear of described full-bridge circuit are connected with magnification circuit plate, direct circuit board communications respectively by input connector P1, described signal output part comprises anode Vin+ to each passage output difference divided voltage signal and negative terminal VIN-, and described feeder ear comprises anode VCC and the negative terminal AGND of full-bridge circuit.

7., as claimed in claim 6 for the preamplifier of wind-tunnel balance signal measurement, it is characterized in that, the inwall of described input connector P1, out connector P2 link has two different grooves of spacing distance, wherein

Described input connector P1 provides input interface for strain balance signal measurement, it comprises the second input connector Xs2 that the first input connector Xs1 of being connected with magnification circuit plate and direct circuit plate connect, the each passage input pin of tested balance signal is set in it respectively, the level bridge pressure input of tested sky, feedback pin and grounding pin, be also provided with in described second input connector Xs2 and amplify power supply input pin;

Described out connector P2 provides signal output interface for data collection station, it comprises amplifying end out connector XS3 and leading directly to holds input connector Xs4, each channel signal output pin is respectively arranged with, the input of tested sky level bridge pressure, feedback pin groove and grounding pin in it.

8. as claimed in claim 1 for the preamplifier of wind-tunnel balance signal measurement, it is characterized in that, also comprise and being arranged on outside described magnification circuit plate, direct circuit plate to realize the insulation division board of itself and other mechanism's electrical isolation.

9., to the method that each signal amplification channel in preamplifier according to any one of claim 1 ~ 8 is calibrated, it is characterized in that, comprising:

Step one, at the input connector end of described magnification circuit plate to each passage input i the simulated strain balance signal Ei in described 8 signal amplification channels, then export i magnitude of voltage X after each signal amplification channel amplification at out connector end _i, wherein said simulated strain balance signal Ei is magnitude of voltage at the direct current signal of-50 ~ 50 millivolts;

Step 2, described data collection station receive i the magnitude of voltage X that each signal amplification channel exports _i, and the calibration parameter of each signal amplification channel is calculated based on i the simulated strain balance signal Ei that each signal amplification channel inputs, described calibration parameter is obtained by following formula:

$k=\frac{\underset{i=1}{\overset{11}{\mathrm{\Σ}}}{x}_i\underset{i=1}{\overset{11}{\mathrm{\Σ}}}{E}_i-11\×\underset{i=1}{\overset{11}{\mathrm{\Σ}}}{x}_i{E}_i}{{\left(\underset{i=1}{\overset{11}{\mathrm{\Σ}}}{E}_i\right)}^2-11\underset{i=1}{\overset{11}{\mathrm{\Σ}}}{E_i}^2}$

$b=\frac{\underset{i=1}{\overset{11}{\mathrm{\Σ}}}{x}_i{E}_i\underset{i=1}{\overset{11}{\mathrm{\Σ}}}{E}_i-\underset{i=1}{\overset{11}{\mathrm{\Σ}}}{x}_i\underset{i=1}{\overset{11}{\mathrm{\Σ}}}{E_i}^2}{{\left(\underset{i=1}{\overset{11}{\mathrm{\Σ}}}{E}_i\right)}^2-11\underset{i=1}{\overset{11}{\mathrm{\Σ}}}{E_i}^2}$

10. adopt calibration steps according to claim 9 to measure a method for wind-tunnel balance signal, it is characterized in that, comprising:

Step one, input strain balance signal by wind-tunnel balance to 8 signal amplification channels of magnification circuit plate simultaneously;

Each passage of step 2, described magnification circuit plate, based on the strain balance signal received, after carrying out filter and amplification, exports the voltage signal Vout after amplifying by described modulate circuit _j;

Step 3, described data collection station receive the voltage signal Vout of each signal amplification channel output of magnification circuit plate by described out connector _j; And based on each signal amplification channel calibration parameter k and b, adopt following formulae discovery to go out the voltage signal Vin of strain balance output _j,

Vin _j＝(Vout _j-b _j)/k _j

Wherein, j is 8 signal amplification channels of 0-7, b _jand k _jbe respectively slope and the intercept of each amplifying signal passage fitting a straight line.