A kind of temperature compensation of electric slope angle sensor and device
One, technical field
The present invention relates to a kind of electric slope angle sensor temperature compensation and device, especially a kind of method and apparatus that the servo obliquity sensor of force balance type is carried out temperature compensation.
Two, background technology
Electric slope angle sensor is widely used in the incline measurement in fields such as military weapon system, space flight, naval vessels, steamer, offshore production platform, bridge, skyscraper.Come to divide from principle of work, can be divided into three kinds of " solid pendulum " formulas, " liquid pendulum " formula, " gas pendulum " formula.The resolution of at present external electric slope angle sensor is very high, and the resolution of force balance type servo-drive system obliquity sensor is 0.2 ", the resolution of liquid pendulum-type obliquity sensor reaches 0.02 "; The electric slope angle sensor resolution of domestic development is more much lower than external like product.Wherein, the resolution of force balance type servo-drive system obliquity sensor is 60 ", the resolution of liquid pendulum-type obliquity sensor is 2 ", pendulum type in-gas inclination device resolution is 36 ".Because the motion control of gas is comparatively complicated, and motion-affecting factor is more, high-precision gas pendulum-type dip angle device also is in the experimental study stage, though liquid pendulum-type obliquity sensor has higher resolution, but the defective that has the linearity and poor repeatability can't satisfy the requirement that military armament systems are used.
The servo electric slope angle sensor of force balance type has linearity height (can reach 5/10000ths), good reproducibility, sluggishness is little, the temperature drift linearity is good, plurality of advantages such as operating temperature range is wide, strong shock resistance, anti-shake performance are good.It is made up of five parts such as non-contact displacement sensor, torque-motor, sum of errors amplifying circuit, feedback circuit, cantilever masses.Wherein: the armature of cantilever mass and torque-motor links together, and non-contact displacement sensor is used to detect the displacement of mass.The principle of work of the servo electric slope angle sensor of force balance type is: when electric slope angle sensor run-off the straight θ angle, cantilever mass m just leaves original equilibrium position and produces moment T=mgl sin θ (l is the equivalent jib-length of mass, g is an acceleration of gravity), after non-contact displacement sensor detects this variation, position signalling is sent into the sum of errors amplifying circuit, on the one hand sensor output and the proportional current i in inclination angle; On the other hand, this signal is sent into the coil of torque-motor through feedback circuit, and at this moment, torque-motor can produce opposite, an equal-sized moment T with cantilever mass direction of motion
Oc, try hard to make the cantilever mass to get back to original equilibrium position, this moment balances each other with moment T, returns to the equilibrium position once more up to responsive mass m, i.e. T under equilibrium state
Oc=T.At this moment, the signal of sensor output is only real useful signal.
Owing to the characteristic of parts such as non-contact displacement sensor, cantilever mass along with variation of temperature changes.Therefore the output of electric slope angle sensor is subjected to the influence of environment temperature, the temperature drift phenomenon can appear, if it is not carried out temperature compensation, just can't satisfy of the accuracy requirement of military and space field at wide operating temperature range (40 ℃~+ 85 ℃) horizontal tilt angular measurement.Traditional temperature compensation measure is to increase thermal sensing element, by in bridge circuit, being connected in series the variation that thermal sensing element comes temperature sensor, the temperature varying coefficient of requirement thermal sensing element and the temperature varying coefficient of electric slope angle device are proportional, and shortcomings such as thermal sensing element exists, and precision is low, the linearity and poor repeatability bring difficulty for components and parts type selecting and electronic circuitry design.
Three, summary of the invention
The present invention is the temperature drift problem of solution force balance type servo-drive system electric slope angle sensor, and proposes a kind of temperature compensation and device of force balance type servo-drive system obliquity sensor.
Technical solution of the present invention is: a kind of electric slope angle sensor temperature compensation, and its special character is: this method may further comprise the steps:
1) with electric slope angle sensor output with the sinusoidal proportional simulating signal filter away high frequency noise in pitch angle after, convert digital signal AD to;
2) measure electric slope angle sensor environment temperature on every side in real time, obtain temperature variation Δ T;
3) according to the temperature compensation computing formula:
Calculate the pitch angle Tilt after the compensation,
Wherein, AD represents the data of A/D converter output; K_AD represents the output voltage gradient of AD converter, unit: 1/ volt; B0 represents benchmark zero bias-voltage, unit: volt; B_temp represents the zero deviation coefficient, unit: volt/℃; Δ T represents temperature variation, unit: ℃; S.F._Temp represents the temperature varying coefficient of scale factor;
A kind of temperature compensation means of realizing above-mentioned electric slope angle sensor temperature compensation, its special character is: this device comprises electric slope angle sensor 101, wave filter 102, A/D converter 103, single-chip microcomputer 105, temperature sensor 106 and power supply 107, behind the analog voltage signal process wave filter 102 ripple devices of electric slope angle sensor 101 outputs, be sent to A/D converter 103, convert thereof into digital angle information, pass through I then
2The C bus is sent into single-chip microcomputer 105, and temperature sensor 106 is measured the environment temperature around the electric slope angle sensor 101 in real time, passes through I
2The C bus is sent into single-chip microcomputer 105, and power supply 107 is given whole temperature compensation means power supply.
Said apparatus also includes output circuit 106, and export by output circuit 106 at the digital pitch angle that single-chip microcomputer 105 calculates after the temperature compensation.
Above-mentioned electric slope angle sensor 101 adopts LCF-100 or LCF_160/165 type electric slope angle device.
Above-mentioned wave filter 102 adopts OPT27, OPT37 or MXL1007 type second order filter.
Above-mentioned A/D converter 103 adopts ADS1210, AD667, AD7663 or AD7665 type A/D converter.
Above-mentioned single-chip microcomputer 105 adopts AT89C52, AT89C51 or AT89C55 type single-chip microcomputer.
Said temperature sensor 104 adopts DS1624, DS6129 or DS1631 type temperature sensor.
Temperature compensation principle of the present invention is: the aanalogvoltage V of electric slope angle device output and the sine of tilt angle theta are approximated to linear relationship, are 20 ℃ in environment temperature, when the pitch angle is 0 °, and the output of electric slope angle device contains zero deviation V0; Along with variation of temperature, pitch angle-output voltage curve is with upper and lower translation, and its translational movement is:
ΔV=K*t (1)
Wherein K is the zero deviation coefficient, unit: V/ ℃; T is an environment temperature, unit: ℃; Δ V is the zero deviation value, unit: volt.Therefore the temperature variant desirable equation of aanalogvoltage of electric slope angle device output is:
V=V
0+ΔV+K
0*sin(θ)=V
0+K*t+K
0*sin(θ) (2)
Wherein K0 is the conversion proportion factor of electric slope angle device.
Because the measurement range of electric slope angle device is ± 1 °, can substitute the sine value of angle with radian value, its error of calculation is:
This value can be ignored.Then formula (2) is reduced to:
V=V
0+K*t+K
0*θ (3)
From formula (3) as can be seen, tilt angle theta is the function with the environment temperature linear change, therefore in order to make the electrical tilt angle measuring device satisfy angle measurement accuracy in wide operating temperature range, must carry out temperature compensation to the voltage of dip angle device output, its principle utilizes formula (3) to eliminate the K*t item exactly.Concrete compensation method is: gather environment temperature and dip angle device output voltage when single chip computer AT 89C52 passes through the P1 cause for gossip, go out Δ V according to known zero temperature coefficient calculations, eliminate because the deviation that temperature variation causes calculates revised angle of inclination value.
Electrical tilt hornwork temperature compensation computing formula is:
output=Bias+S.F.*sin(Tilt+Alig) (4)
In the formula (4): output, Bias represent the output voltage and zero bias-voltage of dip angle device, unit: volt respectively; Tilt, Alig represent respectively to take measurement of an angle and angle correction unit: radian; S.F. represent the conversion proportion factor.
Consider temperature coefficient and uniform units, formula (4) becomes:
In the formula (5): AD represents the data of A/D converter output; K_AD represents the output voltage gradient of AD converter, unit: 1/ volt; B
0Expression benchmark zero bias-voltage, unit: volt; B_temp represents the zero deviation coefficient, unit: volt/℃; Δ T represents temperature variation, unit: ℃; S.F._Temp represents the temperature varying coefficient of scale factor; Here suppose middle Alig=0 ° of formula (4) earlier, then formula (5) becomes:
Make O
0=K_AD*B
0(6)
O
T=K_AD*B_Temp*ΔT (7)
Then computing formula becomes:
AD=O
0+O
T+K
T*Tilt (9)
In sum, as long as calculate O respectively
0, O
TAnd K
T, can calculate revised angle of inclination value Tilt according to formula (9) then.Therefore, utilization is based on the method for the present invention of this principle, can be compensated the angle of inclination value Tilt after the temperature, that is to say after the temperature drift effects that to be eliminated angle of inclination value Tilt accurately, use the temperature compensation means that method of the present invention draws simultaneously, have measuring accuracy and stability height, advantage such as the linearity and good reproducibility, can reach 3 by the T3 transit in the measuring accuracy of-40 ℃ of-+85 ℃ of temperature ranges "; it is suitable for the temperature compensation of various force balance type servo-drive system electric slope angle sensors; its temperature compensation parameter can be revised by the serial ports interrupt mode, so the present invention can be widely used in the high precision Inclination Angle Measurement System.
Four, description of drawings
The structural representation of Fig. 1 apparatus of the present invention;
Fig. 2 is the program flow diagram of preferred embodiment of the present invention.
Five, embodiment
Method of the present invention may further comprise the steps:
1) with electric slope angle sensor output with the sinusoidal proportional simulating signal filter away high frequency noise in pitch angle after, convert digital signal AD to;
2) measure electric slope angle sensor environment temperature on every side in real time, obtain temperature variation Δ T;
3) according to the temperature compensation computing formula:
Calculate the pitch angle Tilt after the compensation,
Wherein, AD represents the data of A/D converter output; K_AD represents the output voltage gradient of AD converter, unit: 1/ volt; B0 represents benchmark zero bias-voltage, unit: volt; B_temp represents the zero deviation coefficient, unit: volt/℃; Δ T represents temperature variation, unit: ℃; S.F._Temp represents the temperature varying coefficient of scale factor, and in this formula, except that AD, Δ T, Tilt, other are constant.
Referring to Fig. 1, the inventive system comprises electric slope angle sensor 101, wave filter 102, A/D converter 103, single-chip microcomputer 105, temperature sensor 106 and power supply 107, because the aanalogvoltage of electric slope angle device sensor 101 outputs contains higher hamonic wave, therefore the analog voltage signal of its output is by after the high fdrequency component of wave filter 102 filtering output signals, be sent to A/D converter 103, convert thereof into digital angle information, pass through I then
2The C bus is sent into single-chip microcomputer 105, and temperature sensor 106 is measured the environment temperature around the electric slope angle sensor 101 in real time, passes through I
2The C bus is sent into single-chip microcomputer 105, and power supply 107 is given whole temperature compensation means power supply, and device of the present invention also can include output circuit 106, and export by output circuit 106 at the digital pitch angle that single-chip microcomputer 105 calculates after the temperature compensation.
Wherein electric slope angle sensor 101 adopts LCF-100 or LCF_160/165 type electric slope angle device.
Wave filter 102 adopts OPT27, OPT37 or MXL1007 type second order filter.
A/D converter 103 adopts ADS1210, AD667, AD7663 or AD7665 type A/D converter.
Single-chip microcomputer 105 adopts AT89C52, AT89C51 or AT89C55 type single-chip microcomputer.
Temperature sensor 104 adopts DS1624, DS6129 or DS1631 type temperature sensor.
Below in conjunction with preferred embodiment the present invention is done further detailed description:
The LCF-100 type electric slope angle device that electric slope angle sensor 101 selects for use Jewell instruments company to produce, it belongs to force balance type servo-drive system electric slope angle device, measurement range ± 1 °, it is output as aanalogvoltage, is directly proportional with the sine at angle of inclination.This dip angle device has characteristics such as resolution height, response speed is fast, the linearity is good.The aanalogvoltage of LCF-100 type electric slope angle device output contains higher hamonic wave, therefore the analog voltage signal of its output is by after the high fdrequency component of OPT27 type second order filter filtering output signal, be sent to A/D converter 103, A/D converter 103 adopts the ADS1210P type A/D converter of Burr-Brown company, it is a kind of 24 resolutions, wide dynamic range, single 5V power supply, ∑-Δ the high-precision a/d converter of band self-correcting function, its inside is by programmable gain amplifier, the second order sigma-delta modulator, the modulator control unit, three exponent number character filters, microcontroller, registers group, compositions such as fiducial reference source and clock circuit.ADS1210P type A/D converter passes through I with the digital quantity of conversion
2The C bus is sent to single-chip microcomputer 105.Single-chip microcomputer 105 is selected the AT89C52 type single-chip microcomputer of Atmel company for use, and it is a kind of high-performance microprocessor with 8K byte flash memory, and is compatible fully with the 80C52 of Intel Company.Temperature sensor 104 is selected the DS1624 type digital temperature sensor of Dallas Semiconductor company for use, it has the measuring accuracy height, and it is wide to measure temperature range, easily and characteristics such as interface microcontroller, its inside also has the E2ROM of 256 bytes, is used to store the corrected parameter of measuring system.DS1624 type digital temperature sensor is gathered the ambient temperature of LCF-100 type electric slope angle device in real time, and the temperature value of gathering is passed through I
2The C bus is sent into AT89C52 type single-chip microcomputer.AT89C52 type single-chip microcomputer is the core of apparatus of the present invention, and P1 mouth and ADS1210P type A/D converter, DS1624 type digital temperature sensor constitute I flexibly to utilize it
2The C bus is gathered in real time to the pitch angle and the environment temperature of LCF-100 type electric slope angle device, and according to the temperature compensation formula data of gathering is carried out computing, and result of calculation is sent to host computer with the serial ports interrupt mode by the RS-422 interface.
Referring to Fig. 2, the specific procedure of preferred embodiment of the present invention is as follows
Step 201: initialization DS1624.Single chip computer AT 89C52 writes the initialization command word by the P0 mouth to DS1624.
Step 202: initialization ADS1210P.Single chip computer AT 89C52 writes the initialization command word by the P0 mouth to ADS1210.
Step 203: reading of data from EEROM, in design, correlation parameter with the electric slope angle sensor temperature compensation leaves among the EEROM of DS1624, as: constant zero deviation, zero inclined to one side temperature coefficient, scale factor, the temperature coefficient of scale factor, the conversion proportion of A/D, the Turbo of A/D converter is provided with, when powering up startup, single chip computer AT 89C52 will pass through I at every turn
2The C bus is read these parameters among the RAM from the EEROM of DS1624, so that the program of back is used.
Step 204: calculate the constant zero deviation, according to formula O
0=K_AD*B
0(6), calculate O
0
Step 205: collecting temperature, read the real time temperature that DS1624 collects, and it left in the corresponding storage space of RAM.
Step 206: calculate the coefficient relevant, according to formula O with temperature
T=K_AD*B_Temp* Δ T (7) and
(8) calculate O
TAnd K
T
Step 207: gather the data of LCF-100, single chip computer AT 89C52 reads the data after the ADS1210P conversion, and it is left in the unit that responds among the RAM.
Step 208: result of calculation, according to formula AD=O
0+ O
T+ K
T* Tilt (9) calculates the pitch angle after the compensation.
Step 209: judge whether to gather and calculated 10 secondary data,, all calculate 10 secondary data at every turn, do level and smooth again in order to improve precision.Calculate 10 secondary data if gathered, then forwarded step 205 to; If also do not gather 10 secondary data, then change the data that step 207 continues to gather dip angle device, again result of calculation.