CN110972554B - Frequency-response frequency-point-by-frequency-point calibration device for displacement sensor - Google Patents
Frequency-response frequency-point-by-frequency-point calibration device for displacement sensor Download PDFInfo
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- CN110972554B CN110972554B CN201418009777.5A CN201418009777A CN110972554B CN 110972554 B CN110972554 B CN 110972554B CN 201418009777 A CN201418009777 A CN 201418009777A CN 110972554 B CN110972554 B CN 110972554B
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Abstract
The invention belongs to the technical field of dynamic measurement of displacement sensors, and particularly relates to a frequency response point-by-point calibration device for a displacement sensor. The technical scheme of the invention firstly provides that the dynamic calibration of the frequency response is a new definition of the after-calibration after the change value is stored, so that the dynamic calibration of the frequency response is legal. The large-stroke high-frequency reciprocating displacement simulation motion device designed by the principle of a push-pull spring oscillator obtains a stroke of +/-25 mm by minimum driving energy and slow release of the energy; the reciprocating frequency is 0-100 Hz, and the high difficulty is caused by instantaneous mechanical motion, so that the influence of errors caused by equipment vibration is minimized, and the fact that the calibrating instrument can run in a laboratory in a stable environment is guaranteed, and the measuring precision is not lost.
Description
Technical Field
The invention belongs to the technical field of dynamic measurement of displacement sensors, and particularly relates to a frequency response point-by-point calibration device for a displacement sensor.
Background
The displacement sensor is a sensor for measuring length, has various types, and is widely applied to the fields of industrial and agricultural production, national defense and military industry. The mounting measurement method can be divided into two main categories, namely contact type and non-contact type. Most displacement sensors work in a low-frequency slow-speed quasi-static environment, but some displacement sensors work in a high-frequency high-speed severe environment, the static indexes of the displacement sensors cannot reflect the characteristics of the displacement sensors in a high-frequency high-speed use environment, and the dynamic technical indexes of the displacement sensors are selected. However, the displacement sensor sold in the market at present only marks the uncertainty index of the static measurement, and therefore, whether the measurement meets the accuracy requirement when the displacement sensor works under the high dynamic environment condition cannot be judged. Two basic conditions are required to determine whether a displacement sensor can operate in a highly dynamic environment. First, its design principle; and secondly, whether the dynamic calibration of a metering department is performed or not. The frequency-displacement calibration is one of important indexes for dynamic calibration of the displacement sensor and is used for evaluating the measurement accuracy of the displacement sensor in a high-frequency reciprocating working environment. The large-stroke +/-25 mm displacement simulation motion device with the frequency response range of 0-100 Hz and the frequency response measurement uncertainty evaluation method are the main research contents at present.
The static calibration of the displacement sensor at home and abroad is mostly carried out by adopting a length measuring instrument, the static measurement accuracy index is very high, and the technology is very mature; however, the calibration of the displacement sensor under the conditions of dynamic, large-stroke and high-frequency reciprocating operation is not reported.
Disclosure of Invention
Technical problem to be solved
The technical problem to be solved by the invention is as follows: the method fills the blank of the dynamic calibration scheme under the conditions of dynamic, large-stroke and high-frequency reciprocating working in the prior art.
(II) technical scheme
In order to solve the above technical problem, the present invention provides a frequency response point-by-point calibration apparatus for a displacement sensor, the apparatus comprising: the device comprises a large hand wheel 1, a small hand wheel 2, a left shaft guide rail seat 3, a left spring 6, a shaft stop 4, a right spring 7, a right shaft guide rail seat 5, a guide rod shaft 8, a light target 12, a calibrated displacement sensor 9, a photoelectric displacement calibration source 10 and a data acquisition processing system 11 which is respectively connected with the calibrated displacement sensor 9 and the photoelectric displacement calibration source 10;
one end of the guide rod shaft 8 is provided with an external thread which is nested in an internal thread arranged in the middle of the big hand wheel 1, and the other end is fixed with a light target 12;
the guide rod shaft 8 and a pull rod of the calibrated displacement sensor 9 are fixedly connected with each other, namely, the optical target 12 is connected with the pull rod of the calibrated displacement sensor 9 by the guide rod shaft 8 to form a synchronous motion assembly, and meanwhile, the photoelectric displacement calibration source 10 is also arranged on one side of the optical target 12 in a direction parallel to the motion direction of the pull rod of the calibrated displacement sensor 9; when the optical target 12 moves, the pull rod of the calibrated displacement sensor 9 synchronously moves, displacement data collected by the calibrated displacement sensor 9 is sent to the data collection and processing system 11, and meanwhile, the photoelectric displacement calibration source 10 collects displacement data of the optical target 12 and sends the displacement data to the data collection and processing system 11 by transmitting laser beams to the optical target 12;
a left square shaft guide rail seat 3 is sleeved on one end, facing the large hand wheel 1, of the guide rod shaft 8, a small hand wheel 2 is arranged on the left square shaft guide rail seat 3, and the guide rod shaft 8 can be tightly sleeved or loosened by rotating the small hand wheel 2 through the left square shaft guide rail seat 3;
the left square shaft guide rail seat 3, the left spring 6, the shaft stop 4, the right spring 7 and the right square shaft guide rail seat 5 are sequentially connected, the right shaft guide rail seat 5 is sleeved in the middle of the guide rod shaft 8, and the left spring 6 and the right spring 7 are limited between the left shaft guide rail seat 3 and the right shaft guide rail seat 5; the left spring 6 and the right spring 7 are movably sleeved on the guide rod shaft 8, and meanwhile, elastic force is applied to the guide rod shaft 8;
the guide rod shaft 8 is driven to do damped oscillation reciprocating motion through the left spring 6 and the right spring 7, and the calibrated displacement sensor 9 and the light target 12 are driven to move simultaneously;
the data acquisition and processing system 11 acquires waveform signals from the calibrated displacement sensor 9 and the high-precision photoelectric displacement calibration source 10 to obtain two curves under a designed oscillation frequency law for calibration.
(III) advantageous effects
The invention relates to a displacement sensor dynamic standard source technology, a large-stroke high-frequency reciprocating displacement simulation motion device design technology, a dynamic displacement standard source and calibrated sensor dynamic information acquisition technology and a sensor dynamic uncertainty evaluation technology. The method is suitable for dynamic measurement and calibration of various displacement sensor frequency response indexes.
The technical scheme of the invention firstly provides that the dynamic calibration of the frequency response is a new definition of the after-calibration after the change value is stored, so that the dynamic calibration of the frequency response is legal. The large-stroke high-frequency reciprocating displacement simulation motion device designed by the principle of a push-pull spring oscillator obtains a stroke of +/-25 mm by minimum driving energy and slow release of the energy; the reciprocating frequency is 0-100 Hz, and the high difficulty is caused by instantaneous mechanical motion, so that the influence of errors caused by equipment vibration is minimized, and the fact that the calibrating instrument can run in a laboratory in a stable environment is guaranteed, and the measuring precision is not lost.
Drawings
Fig. 1 is a schematic diagram of a frequency response frequency point-by-frequency point calibration device of a displacement sensor.
Fig. 2 is a waveform diagram of a spring oscillator.
Fig. 3 is a calibration actual waveform diagram.
Detailed Description
In order to make the objects, contents, and advantages of the present invention clearer, the following detailed description of the embodiments of the present invention will be made in conjunction with the accompanying drawings and examples.
At present, a set of laboratory calibration device is needed for evaluating and calibrating the frequency response index of the displacement sensor, and the device can simulate the high-frequency reciprocating displacement working environment of a similar displacement sensor on a future working site. The displacement change of this high-frequency reciprocating displacement moving body, i.e., the optical target, is simultaneously monitored using a standard source, such as a photoelectric displacement CCD, and a displacement sensor that is calibrated. The outputs of the two displacement curve graphs are connected to a high-speed acquisition system for recording and storing to obtain two displacement change curve graphs in the same coordinate system, so that the relation between the dynamically changed magnitude values of the two displacement curve graphs is fixed and is reserved for post-processing. The output curve of the standard source can be used as an agreed true value to evaluate the dynamic measurement uncertainty of the calibrated displacement sensor. The static calibration is real-time calibration from a standard stable value to a calibrated stable value, and the dynamic calibration of frequency response is carried out by utilizing the post calibration of a standard change curve to a calibrated change curve.
In order to achieve the purpose, a set of large-stroke high-frequency reciprocating displacement simulation motion device needs to be designed, namely a scheme of the large-stroke high-frequency reciprocating displacement simulation motion device designed by utilizing the principle of a spring oscillator is utilized, the mechanical motion stroke is +/-25 mm, the reciprocating frequency is 0-100 Hz, the curve data acquisition process required by dynamic calibration is completed instantly, the action time is short, the energy consumption is low, and the ideal working environment required by standard laboratory equipment is achieved.
At present, the biggest problem of carrying out frequency response dynamic calibration by adopting a post calibration method of a standard variation curve to a variation curve to be calibrated is how to design a simulation motion device with a stroke of +/-25 mm and a reciprocating frequency of 0-100 Hz, and the simulation motion device is used for driving a light target to do linear motion. The reciprocating frequency of 0-100 Hz requires a 6000 rpm machine to drive the moving device. Whether a crank-link or cam mechanism solution is used, the start and stop of the machine requires a time course during which a large amount of energy is input to the system in the form of impacts and rotational inertia, causing strong vibrations of the gantry and the measuring device, making the calibration work impossible at all. In order to avoid vibration, the invention designs a driving mechanism scheme of the spring oscillator.
According to the scheme, a pair of springs are used as driving forces, as shown in fig. 1, a guide rod shaft 8 is driven to do damped oscillation reciprocating motion, and the guide rod shaft 8 drives a light target and a calibrated displacement sensor 9 to move. The left square shaft guide rail seat 3, the left spring 6, the shaft stop 4, the right spring 7 and the right shaft guide rail seat 5 are connected in sequence, and the left spring 6 and the right spring 7 are limited between the left shaft guide rail seat 3 and the right shaft guide rail seat 5. The guide rod shaft 8 is connected with the calibrated displacement sensor 9 through a screw nut, and drives the calibrated displacement sensor 9 to move simultaneously.
Before calibration, a guide rod shaft 8 screw is tightened through a large hand wheel 1, so that a left spring 6 is compressed, and a right spring 7 is stretched. Sufficient spring potential energy and displacement amplitude are stored. Then, the small hand wheel 2 and the left shaft guide rail seat 3 tightly press the embracing guide rod shaft 8 to be fixed, and then the large hand wheel 1 is disassembled to prepare the calibrated displacement sensor 9 and the data acquisition processing system 11. When the small hand wheel 2 is suddenly loosened, the left spring 6 pushes the guide rod shaft 8, the right spring 7 pulls the guide rod shaft 8 to move towards the right square shaft guide rail seat 5 on the right side, in the moving process, the left spring 6 stretches and the right spring 7 compresses, when the potential energy of the two springs is equal to the kinetic energy of the guide rod shaft 8, the left spring 6 pulls the guide rod shaft 8, and the right spring 7 pushes the guide rod shaft 8 to move towards the left square shaft guide rail seat 3 on the left side. The guide rod shaft 8 starts to do reciprocating linear motion under the action of spring force pushing and pulling repeatedly, and the calibrated displacement sensor 9 also does reciprocating linear motion due to the fact that the guide rod shaft 8 is fixedly connected with the calibrated displacement sensor 9.
The reciprocating motion of the push-pull spring oscillator is typical single-degree-of-freedom damped free vibration, and the standard form of the differential equation of the damped free vibration is as follows:
in the formula:
x: moving and displacing;
ωn: natural frequency of undamped system;
ξ, relative damping coefficient;
when ξ is less than 1, the free vibration is a small damping case, the general solution of which is:
in the formula:
a: damping a maximum amplitude of vibration;
ωd: there is a natural frequency of the damping system;
wherein:
from the general solution of the equation, it can be concluded that the free vibration of the system is damped vibration under small damping. Amplitude of which is exponential over time
Damped simple harmonic vibrations. The natural vibration frequency of the system is composed of the rigidity coefficient k and the mass of the guide rod shaftm determines that the actual vibration frequency is slightly lower than the natural frequency due to the relative damping coefficient. The actual vibration waveform is shown in fig. 2.
The data acquisition and processing system 11 acquires waveform signals from the calibrated displacement sensor 9 and the high-precision photoelectric displacement calibration source 10, so that two curves under a designed oscillation frequency law can be obtained, and the acquisition quantity of one oscillation period is enough for calibration. FIG. 3 is a diagram of an actually acquired oscillation waveform, and a solid line is a convention truth curve of the output of a calibration source; the dotted line is a waveform curve of the calibrated displacement sensor, the two dynamic curves are fixed afterwards, and a frequency response-displacement calibration report of the calibrated sensor at the frequency point can be obtained through comparison processing. The springs store little energy, the energy is transmitted in the two springs in an interaction mode in the oscillation process, little energy is released to the outside, the energy is released mainly in a spring heating mode, the oscillation tends to stop soon, and the interference on the rack and instrument equipment is minimum.
Take the design of a system with a calibration frequency of 100Hz maximum and an amplitude of 25mm maximum as an example. Assuming that the weight of the guide bar shaft (including the weight of the sensor rod) is 1.5kg, the natural frequency f of the desired system is 100Hz, and the total stiffness coefficient k of the spring is determined as (2 pi f)2M is 592N/mm, because of the push-pull double springs, the length and stiffness coefficient of the two springs are consistent, the stiffness coefficient of a single spring is 296N/mm, because of the existence of the damping coefficient, the actual vibration frequency is slightly lower than the natural frequency of the system, assuming that the relative damping coefficient ξ is 0.6, the actual vibration frequency is 100Hz, the natural frequency of the system should be 125Hz, and the total stiffness coefficient k of the spring is (2 pi f)2M 926N/mm and the stiffness factor of the individual spring is 462N/mm. It is not difficult to engineer a spring with a spring rate of 462N/mm. The mass m is adjusted, the calibration of different frequency points can be realized by changing the vibration frequency of the push-pull spring, and the calibration of 0-100 Hz frequency bands can be realized by carrying out statistics and synthesis on the response of different frequency points.
Specifically, the invention provides a frequency response frequency point-by-frequency point calibration device for a displacement sensor, which comprises: the device comprises a large hand wheel 1, a small hand wheel 2, a left shaft guide rail seat 3, a left spring 6, a shaft stop 4, a right spring 7, a right shaft guide rail seat 5, a guide rod shaft 8, a light target 12, a calibrated displacement sensor 9, a photoelectric displacement calibration source 10 and a data acquisition processing system 11 which is respectively connected with the calibrated displacement sensor 9 and the photoelectric displacement calibration source 10;
one end of the guide rod shaft 8 is provided with an external thread which is nested in an internal thread arranged in the middle of the big hand wheel 1, and the other end is fixed with a light target 12;
the guide rod shaft 8 and a pull rod of the calibrated displacement sensor 9 are fixedly connected with each other, namely, the optical target 12 is connected with the pull rod of the calibrated displacement sensor 9 by the guide rod shaft 8 to form a synchronous motion assembly, and meanwhile, the photoelectric displacement calibration source 10 is also arranged on one side of the optical target 12 in a direction parallel to the motion direction of the pull rod of the calibrated displacement sensor 9; when the optical target 12 moves, the pull rod of the calibrated displacement sensor 9 synchronously moves, displacement data collected by the calibrated displacement sensor 9 is sent to the data collection and processing system 11, and meanwhile, the photoelectric displacement calibration source 10 collects displacement data of the optical target 12 and sends the displacement data to the data collection and processing system 11 by transmitting laser beams to the optical target 12;
a left square shaft guide rail seat 3 is sleeved on one end, facing the large hand wheel 1, of the guide rod shaft 8, a small hand wheel 2 is arranged on the left square shaft guide rail seat 3, and the guide rod shaft 8 can be tightly sleeved or loosened by rotating the small hand wheel 2 through the left square shaft guide rail seat 3;
the left square shaft guide rail seat 3, the left spring 6, the shaft stop 4, the right spring 7 and the right square shaft guide rail seat 5 are sequentially connected, the right shaft guide rail seat 5 is sleeved in the middle of the guide rod shaft 8, and the left spring 6 and the right spring 7 are limited between the left shaft guide rail seat 3 and the right shaft guide rail seat 5; the left spring 6 and the right spring 7 are movably sleeved on the guide rod shaft 8, and meanwhile, elastic force is applied to the guide rod shaft 8;
the guide rod shaft 8 is driven to do damped oscillation reciprocating motion through the left spring 6 and the right spring 7, and the calibrated displacement sensor 9 and the light target 12 are driven to move simultaneously;
the data acquisition and processing system 11 acquires waveform signals from the calibrated displacement sensor 9 and the high-precision photoelectric displacement calibration source 10 to obtain two curves under a designed oscillation frequency law for calibration.
The invention breaks through the design technology of a large-stroke high-frequency reciprocating displacement analog motion device, the dynamic displacement standard source and calibrated sensor dynamic information acquisition technology and the dynamic uncertainty evaluation method of the frequency response of the displacement sensor, and can provide indexes such as output lag, nonlinearity, repeatability, phase shift, measurement uncertainty and the like of the displacement sensor at different frequency points. The method is advanced and belongs to the domestic initiative, no foreign calibration method can be used for reference, and the blank of the field is filled.
The above description is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, several modifications and variations can be made without departing from the technical principle of the present invention, and these modifications and variations should also be regarded as the protection scope of the present invention.
Claims (1)
1. A frequency point-by-point calibration device for frequency response of a displacement sensor is characterized by comprising: the photoelectric displacement calibration device comprises a large hand wheel (1), a small hand wheel (2), a left shaft guide rail seat (3), a left spring (6), a shaft stop (4), a right spring (7), a right shaft guide rail seat (5), a guide rod shaft (8), a light target (12), a calibrated displacement sensor (9), a photoelectric displacement calibration source (10) and a data acquisition processing system (11) which is respectively connected with the calibrated displacement sensor (9) and the photoelectric displacement calibration source (10);
one end of the guide rod shaft (8) is provided with an external thread which is nested in an internal thread arranged in the middle of the big hand wheel (1), and the other end is fixed with a light target (12);
the guide rod shaft (8) is fixedly connected with a pull rod of the calibrated displacement sensor (9), namely, the optical target (12) is connected with the pull rod of the calibrated displacement sensor (9) by virtue of the guide rod shaft (8) to form a synchronous motion assembly, and meanwhile, the photoelectric displacement calibration source (10) is also arranged on one side of the optical target (12) in a direction parallel to the motion direction of the pull rod of the calibrated displacement sensor (9); the optical target (12) moves, meanwhile, the pull rod of the calibrated displacement sensor (9) moves synchronously, displacement data collected by the calibrated displacement sensor (9) are sent to the data collection and processing system (11), meanwhile, the photoelectric displacement calibration source (10) collects displacement data of the optical target (12) and sends the displacement data to the data collection and processing system (11) through transmitting laser beams to the optical target (12);
a left square shaft guide rail seat (3) is sleeved on one end, facing the large hand wheel (1), of the guide rod shaft (8), a small hand wheel (2) is arranged on the left square shaft guide rail seat (3), and the guide rod shaft (8) can be tightly sleeved or loosened by rotating the small hand wheel (2) through the left square shaft guide rail seat (3);
the left square shaft guide rail seat (3), the left spring (6), the shaft stop (4), the right spring (7) and the right shaft guide rail seat (5) are sequentially connected, the right square shaft guide rail seat (5) is sleeved in the middle of the guide rod shaft (8), and the left spring (6) and the right spring (7) are limited between the left shaft guide rail seat (3) and the right shaft guide rail seat (5); the left spring (6) and the right spring (7) are movably sleeved on the guide rod shaft (8), and meanwhile, elastic force is applied to the guide rod shaft (8);
the guide rod shaft (8) is driven to do damped oscillation reciprocating motion through the left spring (6) and the right spring (7), and the calibrated displacement sensor (9) and the light target (12) are driven to move simultaneously;
the data acquisition processing system (11) acquires waveform signals from the calibrated displacement sensor (9) and the photoelectric displacement calibration source (10) to obtain two curves under the designed oscillation frequency for calibration.
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN108018862A (en) * | 2018-01-11 | 2018-05-11 | 西南交通大学 | A kind of flexible foundation component suitable for passive protection net and easy to inspection |
| CN114964620A (en) * | 2022-08-03 | 2022-08-30 | 中国航空工业集团公司北京长城计量测试技术研究所 | Mechanical sensor dynamic calibration analysis method and device, computer equipment and storage medium |
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2014
- 2014-12-24 CN CN201418009777.5A patent/CN110972554B/en not_active Expired - Fee Related
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN108018862A (en) * | 2018-01-11 | 2018-05-11 | 西南交通大学 | A kind of flexible foundation component suitable for passive protection net and easy to inspection |
| CN108018862B (en) * | 2018-01-11 | 2024-01-30 | 西南交通大学 | Flexible foundation component applicable to passive protective net and convenient to patrol |
| CN114964620A (en) * | 2022-08-03 | 2022-08-30 | 中国航空工业集团公司北京长城计量测试技术研究所 | Mechanical sensor dynamic calibration analysis method and device, computer equipment and storage medium |
| CN114964620B (en) * | 2022-08-03 | 2022-10-21 | 中国航空工业集团公司北京长城计量测试技术研究所 | Mechanical sensor dynamic calibration analysis method and device, computer equipment and storage medium |
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