CN103543294B - Micron grating accelerometer testing method based on added mass - Google Patents

Abstract

The invention discloses a micron grating accelerometer testing method based on added mass. The method includes firstly, acquiring sensing head parameters by theoretical calculation and simulation analysis; mounting an accelerometer sensing head on a testing table, and arranging a stabilizing table on the upper surface of an accelerometer central mass; then selecting the mass, number and total weight of added masses; placing the added masses on the stabilizing table sequentially, and allowing the accelerometer to increase inputted acceleration values from 0 g to the upper range of accelerometer measurements gradually; removing the added masses in an inverted sequence until the inputted acceleration values of the accelerometer is decreased to 0 g; then extracting an average of twice outputs of a same acceleration input to output as corresponding acceleration; finally, utilizing the least squares method to calculate the coefficient of each static mathematical model of the accelerometer, and depicting testing curves. The method has the advantages that accuracy of the optical accelerometer can be improved, testing environment is optimized, and testing efficiency of micron grating accelerometer scale factors can be improved.

Description

A kind of micron grating accelerometer method of testing based on additional mass

Technical field

The present invention relates to a micron grating accelerometer technical field, mainly a kind of micron grating accelerometer method of testing based on additional mass.

Background technology

Micron grating accelerometer is a class for the optical inertial device of acceleration measurement and acceleration change, adopt a kind of mechanical structure that semiconductor silicon is formed by micromachined to experience the change of acceleration, the sensing head structure of micron grating accelerometer as shown in Figure 1, comprising: the structures such as centroplasm gauge block 1, semi-girder 2, catoptron 3, micron grating 4.Light source (LD emergent light) incides a micron grating accelerometer sensing head, when by way of micron grating 4, part light is reflected by micron grating 4, and another part again passes through micron grating 4 by micron grating 4 after the catoptron 3 of centroplasm gauge block 1 lower surface reflects; This two parts light, at space interference, forms multilevel striped; When there being acceleration to input, centroplasm gauge block 1 is by inertia force influence, cause semi-girder 2 deformation, as shown in Figure 2, thus the gap between catoptron 3 and micron grating 4 (air chamber) is changed, and then will change from the beam phase that catoptron 3 is reflected back, this will cause the change of final space interference fringe intensity size, and the change thus by measuring fringe intensity just can obtain the size of input acceleration.Micron grating accelerometer has stable performance, highly sensitive, electromagnetism interference, be easy to the advantage such as integrated.In Aero-Space, there is wide prospect the aspects such as automobile, seismic monitoring and military system.But cannot add the input of controlled steady acceleration for the precision of micron grating acceleration and range test existence, the problems such as measurement mechanism volume is excessive, are difficult to the accurate test realizing micron grating accelerometer.

The test of high g precision centrifuge is mainly for detection of the constant multiplier, the accelerometer bias uniform acceleration meter parameter that are greater than accelerometer under 1g acceleration input condition, utilize high g precision centrifuge or stable turntable, the displacement x of accelerometer centroplasm gauge block is caused from extraneous input acceleration a, mass displacement can change the characteristic of a certain physical quantity in accelerometer, the light intensity I of such as grating accelerometer, the electric capacity C of capacitive accelerometer.Obtained the size of acceleration a by the change of measurement light intensity or capacitance variations, thus accelerometer is detected.But this method of testing, requires that centrifuge speed is stablized, malformation is little, it is little to shake and can be arranged on the various radiuses that circular disc precision indeed knows by degree of will speed up meter.Its precision producing acceleration depends on the measuring accuracy of the hydro-extractor radius of clean-up and the precision of hydro-extractor angular velocity of rotation.But hydro-extractor rotation is to the more difficult Measurement accuracy of the radius of clean-up of accelerometer barycenter, and under high g acceleration, require that hydro-extractor size is large, have higher rotational stabilization, this will cause the further complexity of structure and method of testing, be unfavorable for carrying out batch on-line checkingi in real time to accelerometer, cause time of product development to extend.Carry out the apparatus expensive of testing experiment simultaneously, and harsh to Test Condition Requirements, generally not easily meet.

Summary of the invention

According to existing micron grating accelerometer method of testing, the displacement of known accelerometer centroplasm gauge block is the key of sense acceleration, therefore the present invention is based on and control this principle of displacement that external environment changes sensitive-mass block in accelerometer, propose a kind of on the centroplasm gauge block of micron grating accelerometer additional mass, change mass position, the micron grating accelerometer method of testing inputted in order to provide extraneous analog acceleration; Also be applicable to all method of testings with cantilever beam type accelerometer simultaneously, realize especially by subordinate's step:

Step 1: obtain the detection input acceleration scope of micron grating accelerometer sensing head, semi-girder elasticity coefficient, damping and centroplasm gauge block quality.

Step 2: be arranged on testing stand by micron grating accelerometer sensing head, arranges stable table at the centroplasm gauge block upper surface of micron grating accelerometer simultaneously.

Step 3: choose n additional mass, n is natural number, and n>1;

The minimum mass M of monolithic additional mass _minneed meet:

$M_{\min }=\frac{m_s}{2}---\left(1\right)$

In formula (1), m _sfor the corresponding mass that the sensitivity of micron grating accelerometer obtains after converting;

The biggest quality M of monolithic additional mass _maxneed meet:

$M_{\max }=2k\·M_{\min }\≤\frac{M_{\mathrm{total}}}{10}---\left(2\right)$

In formula (2), k is positive integer, k=1,2,3 M _totalfor the gross mass of n additional mass, M _totalselection range:

$M_{\mathrm{total}}=\frac{a_{\max }\·m_{\mathrm{mid}}}{g}-m_{\mathrm{mid}}---\left(3\right)$

In formula (3), m _midfor micron grating accelerometer centroplasm gauge block quality, g is acceleration of gravity; a _maxfor the maximum range of micron grating accelerometer.

Step 4: additional mass is placed on micron grating accelerometer stable table, each test is by input acceleration value G is 0g, stable table successively increases additional mass, make the input acceleration value G incremental variations of micron grating accelerometer, until micron grating accelerometer arrives uppe r limit of measurement range; And when recording the input acceleration value G incremental variations of each micron grating accelerometer, the accekeration that micron grating accelerometer exports.

Step 5: successively remove the additional mass on stable table by the order backward increasing additional mass in step 4, makes the input acceleration value G of micron grating accelerometer successively decrease change, until 0g falls back in input acceleration value G; The input acceleration value G of each micron grating accelerometer of same record successively decrease change time, the accekeration that micron grating accelerometer exports.

Step 6: input acceleration value G incremental variations with successively decrease in change procedure, get input acceleration value G identical time, the output accekeration of micron grating accelerometer carries out being averaging computing, obtains the calibration value that micron grating accelerometer corresponding to selected input acceleration value exports accekeration.

Step 7: the calibration value exporting accekeration according to the micron grating accelerometer obtained in step 6, by least square method, calculates a micron coefficient for grating accelerometer static mathematical model.

Step 8: the test curve describing micron grating accelerometer according to the coefficient of micron grating accelerometer static mathematical model.

The invention has the advantages that:

1, the present invention is based on the micron grating accelerometer method of testing of additional mass, adopt modular member to substitute traditional detection method, shorten the development time, and input noise is little, antijamming capability is strong, is conducive to the raising of optical accelerometer precision;

2, the present invention is based on the micron grating accelerometer method of testing of additional mass, do not need the test that turntable and hydro-extractor can realize micron grating accelerometer constant multiplier, break away from the test of micron grating accelerometer constant multiplier to the dependence of turntable and hydro-extractor, improve test environment;

3, the present invention is based on the micron grating accelerometer method of testing of additional mass, simple, easy to operate compared with traditional constant multiplier method of testing, a micron testing efficiency for grating accelerometer constant multiplier can be improved.

Accompanying drawing explanation

Fig. 1 is micron grating accelerometer structural representation;

Fig. 2 is semi-girder deformed state schematic diagram in micron grating accelerometer;

Fig. 3 is the micron grating accelerometer method of testing process flow diagram that the present invention is based on additional mass;

Fig. 4 is micron grating accelerometer sensing head mounting means and additional mass placement location schematic diagram in the micron grating accelerometer method of testing that the present invention is based on additional mass.

In figure:

1-centroplasm gauge block 2-semi-girder 3-catoptron 4-micron grating

Embodiment

A kind of micron grating accelerometer method of testing based on additional mass of the present invention, as shown in Figure 3, realizes especially by following step:

Step 1: the detected input acceleration scope being obtained micron grating accelerometer sensing head by theory calculate and simulation analysis, semi-girder elasticity coefficient, the sensing head parameters such as damping and centroplasm gauge block quality.

Step 2: be arranged on testing stand by micron grating accelerometer sensing head, installs stable table, as shown in Figure 4 simultaneously on the centroplasm gauge block of micron grating accelerometer.In the circumference of stable table, evenly having pilot hole in the present invention, by inserting guidepost in pilot hole, as the guide rail that stable table moves up and down, making stable table only have the displacement of above-below direction.

Step 3: choose n additional mass, n is natural number, and n>1.

Wherein, the minimum mass M of monolithic additional mass _min(unit is: gram) need meet:

$M_{\min }=\frac{m_s}{2}---\left(1\right)$

In formula (1), m _sfor the corresponding mass that the sensitivity of micron grating accelerometer obtains after converting;

The biggest quality M of monolithic additional mass _max(unit is: gram) need meet:

$M_{\max }=2k\·M_{\min }\≤\frac{M_{\mathrm{total}}}{10}---\left(2\right)$

In formula (2), k is positive integer, k=1,2,3 M _totalfor the gross mass of n additional mass, M _totalselection range can obtain according to micron grating accelerometer range:

$\left\{\begin{array}{c}(M_{\mathrm{total}}+m_{\mathrm{mid}})\·g=q\·x\\ m_{\mathrm{mid}}\·a=q\·x\end{array}\right.---\left(3\right)$

In formula (3), m _midfor micron grating accelerometer centroplasm gauge block quality, g is acceleration of gravity, and q is micron grating accelerometer semi-girder elasticity coefficient; A is acceleration, and a chooses the maximum range of micron grating accelerometer, i.e. a _max; Can obtain according to formula (3) thus:

$M_{\mathrm{total}}=\frac{a_{\max }\·m_{\mathrm{mid}}}{g}-m_{\mathrm{mid}}---\left(4\right)$

Choosing of described mass quantity n should meet accelerometer performance test requirement, namely under the condition accurately can testing micron grating accelerometer sensitivity and range ability, chooses lesser amt as far as possible;

Step 4: by additional mass on micron grating accelerometer stable table, each test is that 0g(is namely without additional mass by input acceleration value G), stable table successively increases additional mass; Make the input acceleration value G incremental variations of micron grating accelerometer thus, until micron grating accelerometer arrives uppe r limit of measurement range (for micron grating accelerometer, its uppe r limit of measurement range refers in design objective, the limit that between mass and grating face, gap changes); And when recording the input acceleration value incremental variations of each micron grating accelerometer, the accekeration that micron grating accelerometer exports.

In the test of above-mentioned micron grating accelerometer, micron grating accelerometer input acceleration value G incremental variations is according to G ₀=0, G ₁=M _min, G ₂=2M _min, G ₃=4M _min..., G _p=M _max; And 2G ₁+ G ₂+ G ₃+ ... + G _p≈ M _total; Wherein, accekeration G subscript 1,2,3 ..., p is incremental variations number of times;

Step 5: successively remove the additional mass on stable table according to the order backward increasing additional mass in step 4, makes the input acceleration value G of micron grating accelerometer successively decrease change, until 0g falls back in input acceleration value G; The input acceleration G value of each micron grating accelerometer of same record successively decrease change time, the accekeration that micron grating accelerometer exports.

Step 6: because accelerometer semi-girder recovers problem, by cause according to increase progressively changes input acceleration value G size with order of successively decreasing time, under the equal-sized condition of input acceleration value G, different actual test output accekeration can be obtained; Thus input acceleration value G incremental variations with successively decrease in change procedure, choose input acceleration value G identical time, the output accekeration of micron grating accelerometer carries out being averaging computing, obtains the calibration value that micron grating accelerometer corresponding to selected input acceleration value G exports accekeration.

Step 7: the calibration value exporting accekeration according to the micron grating accelerometer obtained in step 6, pass through least square method, calculate a micron coefficient for grating accelerometer static mathematical model, comprise the parameters such as the threshold value of micron grating accelerometer, resolution, constant multiplier and nonlinearity.

Step 8: the test curve describing micron grating accelerometer according to the coefficient of micron grating accelerometer static mathematical model.

The quality of micron grating accelerometer stable table in the present invention, the sensing head sensitivity requirement according to theoretical simulation result and micron grating accelerometer is selected, and under the condition ensureing accelerometer working point, stable table Mass accuracy is chosen for ± M _min.In method of testing of the present invention, the quality of stable table can be ignored.

Claims (3)

1., based on a micron grating accelerometer method of testing for additional mass, it is characterized in that: realize especially by following step:

Step 1: obtain the detection input acceleration scope of micron grating accelerometer sensing head, semi-girder elasticity coefficient, damping and centroplasm gauge block quality;

Step 2: be arranged on testing stand by micron grating accelerometer sensing head, arranges stable table at the centroplasm gauge block upper surface of micron grating accelerometer simultaneously;

Step 3: choose n additional mass, n is natural number, and n>1;

The minimum mass M of monolithic additional mass _minneed meet:

$M_{\min }=\frac{m_s}{2}---\left(1\right)$

In formula (1), m _sfor the corresponding mass that the sensitivity of micron grating accelerometer obtains after converting;

The biggest quality M of monolithic additional mass _maxneed meet:

$M_{\max }=2k\·M_{\min }\≤\frac{M_{\mathrm{total}}}{10}---\left(2\right)$

In formula (2), k is positive integer, k=1,2,3 M _totalfor the gross mass of n additional mass, M _totalselection range:

$M_{\mathrm{total}}=\frac{a_{\max }\·m_{\mathrm{mid}}}{g}-m_{\mathrm{mid}}---\left(3\right)$

In formula (3), m _midfor micron grating accelerometer centroplasm gauge block quality, g is acceleration of gravity; a _maxfor the maximum range of micron grating accelerometer;

Step 4: additional mass is placed on stable table, each test is by input acceleration value G is 0g, stable table successively increases additional mass, makes the input acceleration value G incremental variations of micron grating accelerometer, until micron grating accelerometer arrives uppe r limit of measurement range; And when recording the input acceleration value G incremental variations of each micron grating accelerometer, the accekeration that micron grating accelerometer exports;

Step 5: successively remove the additional mass on stable table by the order backward increasing additional mass in step 4, makes the input acceleration value G of micron grating accelerometer successively decrease change, until 0g falls back in input acceleration value G; The input acceleration value G of each micron grating accelerometer of same record successively decrease change time, the accekeration that micron grating accelerometer exports;

Step 6: input acceleration value G incremental variations with successively decrease in change procedure, get input acceleration value G identical time, the output accekeration of micron grating accelerometer carries out being averaging computing, obtains the calibration value that micron grating accelerometer corresponding to selected input acceleration value exports accekeration;

Step 7: the calibration value exporting accekeration according to the micron grating accelerometer obtained in step 6, by least square method, calculates a micron coefficient for grating accelerometer static mathematical model;

Step 8: the test curve describing micron grating accelerometer according to the coefficient of micron grating accelerometer static mathematical model.

2. a kind of micron grating accelerometer method of testing based on additional mass as claimed in claim 1, is characterized in that: micron grating accelerometer input acceleration value G increases progressively according to G ₀corresponding mass is 0, G ₁corresponding mass is M _min, G ₂corresponding mass is 2M _min, G ₃corresponding mass is 4M _min..., G _pcorresponding mass is M _max; And 2 times of G ₁corresponding mass and G ₂, G ₃..., G _pcorresponding quality sum, approximates the quality summation of whole additional mass; Wherein, accekeration G subscript 1,2,3 ..., p is incremental variations number of times.

3. a kind of micron grating accelerometer method of testing based on additional mass as claimed in claim 1, it is characterized in that: the circumference of described stable table evenly has pilot hole, by inserting guidepost in pilot hole, as the guide rail that stable table moves up and down, stable table is made only to have the displacement of above-below direction.