CN103543294A - 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, is mainly a kind of micron grating accelerometer method of testing based on additional mass.

Background technology

Micron grating accelerometer is that a class is for the optics inertia device of acceleration measurement and acceleration change, a kind of mechanical structure that employing semiconductor silicon forms by micromachined is to experience the variation 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, a part of light is by 4 reflections of micron grating, and another part again passes through a micron grating 4 by micron grating 4 after catoptron 3 reflections of centroplasm gauge block 1 lower surface; This two parts light, at space interference, forms multilevel striped; When having acceleration input, centroplasm gauge block 1 is subject to inertia force influence, cause semi-girder 2 deformation, as shown in Figure 2, thereby the gap (air chamber) between catoptron 3 and micron grating 4 is changed, and then the light beam phase place being reflected back from catoptron 3 will change, this will cause the change of final space interference fringe intensity size, just can obtain the size of input acceleration thus by measuring the change of fringe intensity.Micron grating accelerometer has stable performance, highly sensitive, anti-electromagnetic interference (EMI), is easy to the advantages such as integrated.In Aero-Space,, there is wide prospect the aspects such as automobile, seismic monitoring and military system.The problems such as but precision and range test existence for micron grating acceleration cannot add controlled steady acceleration input, and measurement mechanism volume is excessive, are difficult to realize the accurate test of micron grating accelerometer.

High g precision centrifuge test 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, from extraneous input acceleration a, cause the displacement x of accelerometer centroplasm gauge block, mass displacement can change the characteristic of a certain physical quantity in accelerometer, such as the light intensity I of grating accelerometer, the capacitor C of capacitive accelerometer.By measuring, light intensity changes or capacitance variations obtains the size of acceleration a, thereby accelerometer is detected.But this method of testing, requires that centrifuge speed is stable, malformation is little, it is little to shake and can degree of will speed up meter be arranged on disk accurately on known various radiuses.Its precision that produces 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 hydro-extractor size large, have a higher rotational stabilization, this will cause the further complexity of structure and method of testing, be unfavorable for accelerometer to carry out in real time online detection in batches, cause time of product development to extend.Carry out the apparatus expensive of testing experiment simultaneously, and harsh to Test Condition Requirements, be generally difficult for meeting.

Summary of the invention

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

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

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

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

The minimum mass M of monolithic additional mass _minneed to meet:

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

In formula (1), m _sthe corresponding mass obtaining after converting for the sensitivity of micron grating accelerometer;

The biggest quality M of monolithic additional mass _maxneed to 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 _maxmaximum range for micron grating accelerometer.

Step 4: additional mass is placed on micron grating accelerometer stable table, test is that 0g starts by input acceleration value G at every turn, on stable table, successively increase 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 during the input acceleration value G incremental variations of the each micron of record grating accelerometer, the accekeration of micron grating accelerometer output.

Step 5: successively remove the additional mass on stable table by the order backward that increases additional mass in step 4, make the input acceleration value G of micron grating accelerometer variation of successively decreasing, until 0g falls back in input acceleration value G; The input acceleration value G of the each micron of same record grating accelerometer successively decreases while changing, the accekeration of micron grating accelerometer output.

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

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

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

The invention has the advantages that:

1, the micron grating accelerometer method of testing that the present invention is based on additional mass, adopts modular member to substitute traditional detection method, shortened the development time, and input noise is little, and 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 turntable and hydro-extractor can realize the test to micron grating accelerometer constant multiplier, break away from the dependence of micron grating accelerometer constant multiplier test to turntable and hydro-extractor, improved test environment;

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

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 the present invention is based on micron grating accelerometer sensing head mounting means and additional mass placement location schematic diagram in the micron grating accelerometer method of testing of 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, specifically realizes by following step:

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

Step 2: micron grating accelerometer sensing head is arranged on testing stand, on the centroplasm gauge block of micron grating accelerometer, stable table is installed, as shown in Figure 4 simultaneously.Week at stable table in the present invention upwards evenly has pilot hole, and by insert guidepost in pilot hole, the guide rail moving up and down as stable table, makes 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 to meet:

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

In formula (1), m _sthe corresponding mass obtaining after converting for the sensitivity of micron grating accelerometer;

The biggest quality M of monolithic additional mass _max(unit is: gram) need to 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; According to formula (3), can obtain 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,, can accurately testing under the condition of micron grating accelerometer sensitivity and range ability, chooses lesser amt as far as possible;

Step 4: on micron grating accelerometer stable table, test is that 0g(is without additional mass by input acceleration value G at every turn by additional mass) start, on stable table, successively increase additional mass; Make thus the input acceleration value G incremental variations of micron grating accelerometer, 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 during the input acceleration value incremental variations of the each micron of record grating accelerometer, the accekeration of micron grating accelerometer output.

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, the subscript 1,2,3 of accekeration G ..., p is incremental variations number of times;

Step 5: successively remove the additional mass on stable table according to the order backward that increases additional mass in step 4, make the input acceleration value G of micron grating accelerometer variation of successively decreasing, until 0g falls back in input acceleration value G; The input acceleration G value of the each micron of same record grating accelerometer is successively decreased while changing, the accekeration of micron grating accelerometer output.

Step 6: because accelerometer semi-girder recovers problem, by cause according to increasing progressively while changing input acceleration value G size with the order of successively decreasing, under the equal-sized condition of input acceleration value G, can obtain different actual test output accekerations; Thus input acceleration value G incremental variations with successively decrease in change procedure, choose input acceleration value G when identical, the output accekeration of micron grating accelerometer is averaging computing, obtains the calibration value of the micron grating accelerometer output accekeration that selected input acceleration value G is corresponding.

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

Step 8: the test curve of 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, requires to select according to the sensing head sensitivity of theoretical simulation result and micron grating accelerometer, is guaranteeing under the condition of accelerometer working point be chosen for ± M of stable table quality precision _min.In method of testing of the present invention, the quality of stable table can be ignored.

Claims (3)

1. the micron grating accelerometer method of testing based on additional mass, is characterized in that: specifically by following step, realize:

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

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

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

The minimum mass M of monolithic additional mass _minneed to meet:

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

In formula (1), m _sthe corresponding mass obtaining after converting for the sensitivity of micron grating accelerometer;

The biggest quality M of monolithic additional mass _maxneed to 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 _maxmaximum range for micron grating accelerometer;

Step 4: additional mass is placed on stable table, test is that 0g starts by input acceleration value G at every turn, on stable table, successively increase 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 during the input acceleration value G incremental variations of the each micron of record grating accelerometer, the accekeration of micron grating accelerometer output;

Step 5: successively remove the additional mass on stable table by the order backward that increases additional mass in step 4, make the input acceleration value G of micron grating accelerometer variation of successively decreasing, until 0g falls back in input acceleration value G; The input acceleration value G of the each micron of same record grating accelerometer successively decreases while changing, the accekeration of micron grating accelerometer output;

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

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

Step 8: the test curve of 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 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+ ... ten G _p≈ M _total; Wherein, the subscript 1,2,3 of accekeration G ..., 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 week of described stable table upwards evenly has pilot hole, by insert guidepost in pilot hole, the guide rail moving up and down as stable table, makes stable table only have the displacement of above-below direction.

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