CN1195201C - Dynamic measurement time domain compensation method - Google Patents
Dynamic measurement time domain compensation method Download PDFInfo
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Abstract
The present invention relates to a method for compensating time domains during dynamic measurement. In the present invention, a variable curved line of parameters to be measured is approximately regarded as a sectional folding line, and the parameters to be measured are calculated through extrapolation recursion according to turning points of the folding line and slope rate; in order to determine the turning point of the approximate folding line and the slope rate of the folding line of parameter variation to be measured, an output discreet value YK of a corresponding sensor is calculated through recursion based on the transient response analysis of an inertial element first; then a folding line model (the turning point and the slope rate of the folding line of) is dynamically defined based on the difference of the YK and the actual output value yK of the sensor; finally, a folding line signal value uk (namely the dynamic measured value of measured parameters) is obtained through recursion calculation based on the folding line mold dynamically defined. The present invention can effectively improve the response speed and the precision of dynamic measurement; the time domain recursive algorithm is simple, and the real-time property is good; the present invention is suitable for being realized through assembly language by using microcomputers, has the advantages of soft measurement, low cost, high flexibility and intelligence, and is widely suitable for the measurement of various physical quantities with sensors in inertial elements.
Description
One, technical field
The present invention relates to a kind of dynamic parameter measuring technique, be specially adapted to show as the first order inertial loop situation when measuring sensor.
Two, background technology
In the general physical quantity (as temperature, humidity, atmosphere measurement etc.), because there is inertia in measuring sensor (sensor), response speed is measured in influence, thereby influences dynamic measurement precision, and this is a ubiquitous more scabrous problem in measuring technique.Following solution is arranged at present: 1. the measuring sensor of selecting for use different materials to make, material as humidity-sensitive element commonly used comprises: electrolytes, metal oxide-type, high molecular polymer class and semiconductor type, the measurement responsive time constant difference of the element of different materials, be distributed between second level and minute level, select the element of dynamic property good (the time constant is little) during use as far as possible for use; 2. change measuring sensor and make structure, reduce time constant, improve response speed; 3. adopt dynamic compensation according to the measuring sensor responsive time constant.There is following problem in these methods: under the actual conditions, selecting for use of different materials measuring sensor often is subjected to the restriction of atmosphere and environmental baseline, is difficult to accept or reject flexibly according to the good and bad of dynamic property; It is limited that measuring sensor is made structural change, and be not can both realize under all situations; Dynamic compensation is the Domain Dynamic modification method, as: " dynamic perfromance of film thermocouple and Study on dynamic compensation " (metering journal, the 20th rolls up in July, 1999 the 3rd phase) and " Sensor's Dynamic Error Research on correcting method " (Institutes Of Technology Of Nanjing's journal, the 24th rolls up in August, 2000 the 4th phase), mainly constitute analog filter or constitute digital filter and realize with software with mimic channel, the filter order of generally designing is higher, realize having any problem with mimic channel, realize again because of the complicated needs that are difficult to adapt to real-time measurement of algorithm with software; In addition, if dynamic compensation inverse filtering (deconvolution) computing then is generally high way system, the noise signal in the measurement result is amplified, influence precision, sometimes even become diverging system, the inverse filtering result will be more insincere.
Three, summary of the invention
The technical solution adopted for the present invention to solve the technical problems:
The present invention is a kind of kinetic measurement time domain compensation method.It is that change curve with tested parameter is approximately sectional broken line and adopts the extrapolation method recursion to calculate tested parameter according to broken line turning point and slope; In order to determine that tested parameter changes the turning point and the broken line slope of approximate broken line, at first analyze recursion and calculate corresponding sensor output discreet value according to inertial element transient response (sensor model)
(sampling instant, k=0,1,2,3 are measured in the k representative ...), basis then
With sensor real output value y
kDeviation, dynamically determine segmented line model (turning point and broken line slope), last, calculate broken line signal value u by the segmented line model recursion of dynamically determining again
k(being tested parameter kinetic measurement value) is specially:
(1) calculates initial value u
1And K
0
According to u
0(equal the 0th sampling instant and promptly measure the sensor real output value y zero hour
0), y
1(the first sampling instant sensor real output value) and (1), (2) formula
K
0＝(y
1-u
0)×β/T (1)
u
1＝(y
1-u
0)×β×α (2)
Calculate broken line signal initial slope K
0And broken line signal value u
1(constant when T is the sensor inertial element in the formula; Δ is the sampling period; Constant alpha=Δ/T; Constant β=1/ (α+exp (α)-1); Exp () is an exponential function), and with u
1Show output as the tested value of consult volume of first sampling instant;
(2) time domain dynamic compensation computation process
From second sampling instant (k 〉=2), in each sampling period, carry out following calculating:
Sampling sensor real output value y at first
k, then according to (3) formula
(y wherein
K-1, u
K-1, K
K-1Be respectively sensor real output value, broken line calculated signals value, the broken line signal slope of last sampling instant)
Recursion calculating sensor output discreet value
Again according to (4) formula
Calculation deviation ε
k, if absolute value of the bias surpasses setting threshold be not | ε
k|＜M (M is a setting threshold) illustrates that then the broken line signal transfers, according to (5) formula
K
k＝K
k-1 (5)
Recursion is calculated the broken line slope K
k, promptly remain unchanged, and according to (6) formula
u
k＝u
k-1+K
k-1×Δ (6)
Recursion is calculated broken line signal u
k, and show output as the tested value of consult volume of this sampling instant, wait for next sampling instant then; If absolute value of the bias surpasses setting threshold | ε
k| 〉=M illustrates that then the broken line signal transfers, according to (7) formula
K
k＝K
k-1-ε
k×β/T (7)
Recursion is calculated turnover back slope K
k, and according to (8) formula
u
k＝u
k-1+K
k-1×Δ-ε
k×α×β (8)
The formula recursion is calculated broken line signal u
k, and show output as the tested value of consult volume of this sampling instant, wait for next sampling instant then;
(3) circulation
In the next sampling period, returned for (2) step and carry out cycle calculations; Once sampling, cycle calculations once finish until measuring.
Four, description of drawings
Fig. 1 one-chip computer intelligent temperature experiments of measuring system hardware constitutes block diagram
Fig. 2 with thermocouple output signal as step temperature signal measurement result under the temperature measurement result situation
Fig. 3 carries out time domain compensation to thermocouple output signal and calculates step temperature signal measurement result afterwards
Fig. 4 carries out time domain compensation to thermocouple output signal and calculates slope temperature signal measurement result afterwards
The main process flow diagram of computer program of Fig. 5 kinetic measurement time domain compensation algorithm
Five, embodiment
The one-chip computer intelligent temperature experiments of measuring system hardware of making according to kinetic measurement time domain compensation algorithm design constitutes block diagram as shown in Figure 1.Wherein, temperature sensor adopts EU-2 type thermopair, the thermocouple signal output terminal is connected with DDZ-II type temperature transmitter signal input part, and the milliampere current signal of exporting when making thermocouple temperature measurement is transformed to the normal voltage signal, so that carry out analog to digital conversion (ADC); The temperature transmitter signal output part is connected with the input end of analog signal of analog-digital conversion ic chip ADC0809 through low-pass filter, low-pass filter is made of resistance-capacitance circuit, it is inhibited in the high frequency interference at random that the input end of analog signal of modulus conversion chip causes for thermometric environment various factors, improves measuring accuracy; ADC0809 is 8 analog to digital converters, chip translation data register pin is linked to each other with single-chip microcomputer (being one-chip computer) 8031 data buss (DBUS), chip dies number conversion start end is linked to each other with Single-chip Controlling bus (CBUS), chip slapper choosing end is connected with single-chip microcomputer address bus (ABUS), so that under Single Chip Microcomputer (SCM) program control, carry out analog to digital conversion; Peripheral Interface integrated circuit 8279 has driving and level conversion function, 4 figure place sign indicating number display tube pins are connected with 8279 delivery outlets, five numerical function key circuit are connected in 8279 input ports, single-chip data bus (DBUS) is linked to each other with input/outlet register, Single-chip Controlling bus (CBUS) is linked to each other with 8279 read-write control ends, single-chip microcomputer address bus (ABUS) is connected with 8279 choosing ends, constitutes real-time display part of temperature measurement result and program run control section; EPROM2764 is an electrically-alterable ROM (EAROM), RAM8264 is a random access memory, corresponding three buses with 2764 and 8264 of single-chip microcomputer three buses (ABUS, CBUS, DBUS) are connected, constitute single-chip microcomputer Add-In storer and data-carrier store, 8264 chip power ends are connected with power-off protection (battery circuit), so that in measuring process, prevent to cause loss of data because of accident power-off, realize 8031 single-chip microcomputer assembly language program(me)s of kinetic measurement time domain compensation algorithm, be cured among 2784 by the EPROM writing station; Mini-printer HGUD-16T is connected with single-chip microcomputer three buses by parallel interface Centronics, constitutes the measurement result print-out device.Calculating the temp measuring system sampling period is 1 second; System software (program) has also increased system monitoring, constant when testing inertial element automatically, digital filtering and function such as anti-interference except that realizing kinetic measurement time domain compensation algorithm, the program capacity is 5K.
The main process flow diagram of computer program of realization kinetic measurement time domain compensation algorithm is described as follows as shown in Figure 5:
(1) sampling sensor output valve y
0(u
0)
At zero sampling instant (i.e. start is constantly), start the A/D conversion, read in sensor real output value y by CPU external data mouth behind the EOC
0Be u
0(consider the general work actual conditions, be in steady state (SS), then y when establishing measuring sensor and starting working
0=u
0), this process is called sampling (for improving reliability, when sampling, will remove maximin for sampling point continuous sampling 5 times, surplus value is asked on average at every turn, and as sampled value, this process is called digital filtering with mean value), stores u then
0, for calculating relevant initial value, next step prepares, wait for next sampling instant then;
(2) sampling sensor output valve y
1
In first sampling instant, sampling sensor real output value y
1
(3) according to (1), (2) formula calculating K
0, u
1:
According to given data u
0, y
1Reach constant alpha, β, T,, estimate initial broken line slope K according to formula (1) and (2) formula
0And first parameter measurement value u
1And store, for entering circulation measurement calculating, next sampling instant prepares, provide (demonstration) first parameter measurement value u then
1And wait for next sampling instant;
(4) sampling sensor output valve y
k
Adopt constantly from second, entering circulation measurement computation process, the sensor real output value y that afterwards each sampling instant is collected
kStore, so that carry out correlation computations;
(5) according to (3) formula calculating sensor output discreet value
In (3) formula, the constant Δ is the sampling period, according to ratios delta/T situation, is constant value e with the equivalence of exponential function value
-1Or other constant values, to simplify computer program;
(6) is absolute value of the bias less than M?
This is a decision block, and specific implementation is: at first according to (4) formula calculation deviation, ask its absolute value then, if adopt the assembly language programming, can calculate absolute value by supplement, carry out logic determines again, and whether carry out distinct program (processing) less than setting threshold according to absolute value of the bias;
(7a) by (5), (6) formula calculating K
k, u
k
If absolute value of the bias, then illustrates the broken line signal above setting threshold and transfers that according to (5) formula, the broken line slope will remain unchanged, and calculate the broken line signal according to (6) formula recursion again, and the storage computation result;
(7b) by (7), (8) formula calculating K
k, u
k
If absolute value of the bias, then illustrates the broken line signal above setting threshold and transfers, according to slope after (7) formula recursion calculating turnover, calculate the broken line signal according to (8) formula recursion more earlier, and the storage computation result;
(8) the dynamic tested parameter measurement value u of output
k
No matter whether generation transfers, all the broken line signal that the calculates tested parameter measurement result as this sampling instant is exported, and output form or adopt CRT to show, or adopt charactron to show, or be stored in ends to be measured back unification printout in the array;
(9) measure end?
This is a decision block, and specific implementation is: judge that the condition of measuring end is different and different according to the condition that control survey finishes: if control according to Measuring Time, then will read timer value to judge; If judge (as: output valve has reached stable state), then continuous several output valves to be compared, analyze and make judgement according to the sensor output value variation characteristic; If according to manually controlling, then to read manual ringing (or pulse, or level) and judge, and whether finish to carry out distinct program (processing) according to measuring by CPU external data mouth;
(10) next sampling instant?
This is a decision block, and specific implementation is: do not finish if measure, judge whether next sampling instant arrives, and mainly whether zero passage is judged according to sampling period timer again; If next sampling instant no show, then program enters wait-judgement circulation; If next sampling instant arrives, then program jumps to (4) and goes on foot the program entry place, carries out new round sampling-calculating-display result process, moves in circles like this, finishes until measuring;
(11) measure end process
Finish if measure, then enter the end process program, it can be to print whole measurement results (normally printing array), or carries out other forms of end process as required.
The thermometric implementation process is:
(1) is the zero sampling instant after thermometric begins, enter zero sampling processing process: dut temperature becomes current signal by thermopair, become voltage signal by temperature transmitter again, this signal is added to the modulus conversion chip input end through after the low-pass filtering; Executive routine ' sampling sensor output valve y at first after the computing machine energising
0(u
0) ': the computer starting analog to digital conversion, read translation data after waiting for EOC, this process is called sampling, then so samples 4 times continuously again, afterwards 5 sampled datas are carried out digital filtering and calculate, result of calculation is the temperature thermocouple real output value y that this sampling instant obtains
0, store y then
0(u
0), for calculating relevant initial value, next step prepares; Carry out ' waiting for next sampling instant ' program afterwards: cycle detection sampling period timer zero passage indication end detects zero passage indication back program and enters into first sampling processing process;
(2) enter into first sampling processing process after, executive routine ' sampling sensor output valve y
1': obtain this sampling instant temperature thermocouple real output value y
1And store, carry out temperature thermocouple output discreet value cycle calculations for next sampling instant and prepare; Executive routine is ' according to (1), (2) formula calculating K afterwards
0, u
1': according to given data u
0, y
1Reach constant alpha, β, T,, calculate initial broken line slope K according to formula (1) and (2) formula
0And first sampling instant measured temperature u
1And store, carry out the measured temperature cycle calculations for next sampling instant and prepare; Executive routine ' is exported dynamic tested parameter measurement value u afterwards
k': with first measured temperature u
1Write 8279, thereby show as real-time measurement result by 4 charactrons; Carry out afterwards determining program " measure finishing? ": read 8279, thereby obtain manual control survey end functions push button signalling and judge, if pressed button, then carry out ' measurement end process ' program, otherwise, carry out " next sampling instant? " determining program (' waiting for next sampling instant ' program is identical);
(3) suppose not press end key, then " next sampling instant? " enter circulation after the EOP (end of program) and measure computation process, at first carry out " sampling sensor output valve y
k" program: obtain second sampling instant temperature thermocouple output valve y
2(after, by continuous circulation obtain third and fourth, five sampling instant temperature thermocouple output valve y
3, y
4, y
5Or the like up to measure finishing) and store, carry out temperature thermocouple output discreet value cycle calculations for next sampling instant and prepare; Executive routine ' is exported discreet value according to (3) formula calculating sensor ' afterwards: obtain this sampling instant temperature thermocouple output discreet value; ' is absolute value of the bias less than M to carry out determining program afterwards? ': at first according to the output discreet value of this sampling instant temperature thermocouple and this sampling instant temperature thermocouple real output value and (4) formula calculation deviation, ask its absolute value then and whether carry out distinct program (processing) less than setting threshold according to this value; If absolute value of the bias, then illustrates the broken line signal less than setting threshold and transfers that executive routine is " by (5), (6) formula calculating K afterwards
k, u
k": calculate the measured temperature u that does not take place under the turnover situation
2And store; If absolute value of the bias, then illustrates the broken line signal more than or equal to setting threshold and transfers that executive routine is " by (7), (8) formula calculating K afterwards
k, u
k": calculate the measured temperature u that takes place under the turnover situation
2And store; Executive routine " is exported dynamic tested parameter measurement value u after judging
k": with second sampling instant measured temperature u
2Show in real time by 4 charactrons; Carry out afterwards determining program " measure finishing? " judge whether temperature survey is required to finish, measure if proceed, then carry out " next sampling instant? " program, turn back to this section beginning afterwards, carry out new round sampling-calculating-displays temperature measured value process, move in circles like this, constantly the displays temperature measurement result finishes until measuring;
(4) press end key after, executive routine " measurement end process ": will store whole measurement result arrays and write the Centronics parallel interface, and print data and curve by mini-printer HGUD-T16.
Under laboratory condition, be not with the algorithm situation to carry out the experiment of contrast thermometric according to different dut temperature change curves and band algorithm, experimental result is shown in Fig. 2, Fig. 3, Fig. 4 and table 1.Fig. 2 for directly with thermocouple output signal as step temperature signal measurement result under the temperature measurement result situation; Fig. 3 calculates step temperature signal measurement result afterwards for thermocouple output signal being carried out time domain compensation; Fig. 4 is for carrying out time domain compensation calculating afterwards to slope temperature signal measurement result to thermocouple output signal, table 1 is corresponding measurement data.
Table 1 thermometric experimental data
| ?t 0.5T 1.0T 1.5T 2.0T 2.5T 3.0T 3.5T 4.0T ?u(％) 39.3 63.2 77.7 86.5 91.8 95.0 97.0 98.2 ?u’(％) 98 99 100 98 99 99 100 99 ?h 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 ?u h 0.11 0.37 0.73 1.14 1.58 2.05 2.53 3.02 ?u h’ 0.46 1.04 1.48 2.05 2.49 3.03 3.47 4.04 |
In the table:
Constant h was the slope temperature signal when T was inertial element
U is step temperature signal measurement result (no algorithm) u
hBe slope temperature signal measurement result (no algorithm)
U ' is step temperature signal measurement result (algorithm is arranged) u
h' be slope temperature signal measurement result (algorithm is arranged)
According to table 1 data, measurement for the step temperature signal, if do not adopt the time domain compensation algorithm, time of 98.2% that measured value can be reflected to the dynamic temperature exact value be 4T constantly, and after adopting the time domain compensation algorithm, time of 98% that measured value can be reflected to the dynamic temperature exact value be 0.5T constantly, measure response speed and improved 7 times; From another viewpoint, if do not adopt the time domain compensation algorithm, be 39.3% of exact value then in 0.5T measurement result constantly, behind the employing time domain compensation algorithm, 0.5T measurement result constantly is 98% of an exact value, measuring accuracy improves 58%; Equally,, can find out also that the time domain compensation method can improve the speed and the precision of dynamic temperature measurement by table 1 data for the slope temperature signal.
So, adopt kinetic measurement time domain compensation method, can effectively improve dynamic temperature measurement response speed and dynamic temperature measurement precision; Recursive algorithm is simple, and real-time is good, is fit to realize with computer software, and implementation language is brought into play " soft measurement " advantage without limits, and dirigibility is good, also generally is suitable for other physical quantities except that temperature, as long as survey sensor shows as inertial element.
Claims (1)
1. a kinetic measurement time domain compensation method is characterized in that, the change curve of tested parameter is approximately sectional broken line, and adopts the extrapolation method recursion to calculate tested parameter according to broken line turning point and slope; In order to determine that tested parameter changes the turning point and the broken line slope of approximate broken line, at first, calculate corresponding sensor output discreet value according to inertial element instantaneous response analysis recursion
Basis then
With sensor real output value y
kDeviation, dynamically determine segmented line model, promptly determine turning point and broken line slope, last, calculate broken line signal value u by the segmented line model recursion of dynamically determining again
k, promptly tested parameter kinetic measurement value, concrete calculation procedure is:
Calculate broken line signal initial slope K according to (1), (2) formula
0And broken line signal value u
1
K
0＝(y
1-u
0)×β/T (1)
u
1＝(y
1-u
0)×α×β (2)
U wherein
0Equal to measure the sensor real output value zero hour, y
1Be the first sampling instant sensor real output value, constant when T is the sensor inertial element, Δ are the sampling period, α=Δ/T, β=1/ (α+exp (α)-1);
According to (3) formula recursion calculating sensor output discreet value
Y wherein
K-1, u
K-1, K
K-1Be respectively sensor real output value, broken line calculated signals value, the broken line signal slope of last sampling instant;
According to (4) formula
Thereby whether calculation deviation for the broken line signal turnover takes place judge, if absolute value of the bias less than setting threshold, then is judged as the broken line signal and transfers, if absolute value of the bias more than or equal to setting threshold, then is judged as the broken line signal turnover has taken place;
According to the broken line signal whether turnover taking place selects following calculating: when the broken line signal is transferred, according to (5), (6) formula
K
k＝K
k-1 (5)
u
k＝u
k-1+K
k-1×Δ (6)
Recursion is calculated the broken line slope K
kWith broken line signal u
k, when turnover takes place in the broken line signal, according to (7), (8) formula
K
k＝K
k-1-ε
k×β/T (7)
u
k=u
K-1+ K
K-1* Δ-ε
k* α * β (8) recursion is calculated the broken line slope K
kWith broken line signal u
k
In the next sampling period, repeat aforementioned calculation (3)～(8) formula process; Once sampling, cycle calculations once finish until measuring.
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|---|---|---|---|
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| CN102661705B (en) * | 2012-05-23 | 2014-08-20 | 江西省智成测控技术研究所有限责任公司 | Asynchronous sampling-based adaptive dynamic error compensation method and device |
| EP2682715B1 (en) | 2012-07-02 | 2015-03-11 | Sensirion AG | Portable electronic device |
| DE102017204236A1 (en) * | 2017-03-14 | 2018-09-20 | Robert Bosch Gmbh | Method for operating a sensor for detecting at least one property of a measuring gas in a measuring gas space |
| CN109899167B (en) * | 2019-01-31 | 2022-07-15 | 一汽解放汽车有限公司 | Engine manifold temperature dynamic control method |
| CN113758503B (en) * | 2021-08-12 | 2022-03-18 | 清华大学 | Process parameter estimation method and device, electronic equipment and storage medium |
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