CN103206966B - Precision measurement error correction method for single-axis air bearing table - Google Patents

Abstract

The invention relates to the technical field of measurement, and particularly relates to a precision measurement error correction method for a single-axis air bearing table, which solves the problems of unstable precision, poor compensation effect and the like of the existing rotation angle measurement error correction method. The precision measurement error correction method for the single-axis air bearing table comprises the following steps: regulating balance of an air bearing table, and subtracting the reading alpha i(i=1, 2, -, 17) of a computer by a selected detection angle beta i(i=1, 2, -, 17) to obtain a result which is equal to the rotation angle error value yi(i=1, 2, -, 17) of the air bearing table; according to a formula shown in the description, conducting linear interpolation correction to xi=i(i=1, 2, -, 17), respectively calculating 16 linear piecewise functions, and correcting a grating angle displayed by the computer; then measuring a new rotation error value zi(i=1, 2, -, 17), conducting harmonic correction according to the formula shown in the description, calculating a harmonic correction function, correcting the grating angle displayed by the computer to obtain a final rotation angle error value si(i=1, 2, -, 17), determining whether the rotation error value is larger than the required precision, and conducting harmonic correction again if the rotation error value is larger than the required precision, otherwise, processing the final result. The air bearing table precision measurement error correction method provided by the invention has the advantages of simple structure, low cost and high angle measurement precision.

Description

A kind of single-axle air bearing table precision measurement error calibration method

Technical field

The present invention relates to a kind of single-axle air bearing table precision measurement error calibration method, relate to field of measuring technique.

Background technology

Single-axle air bearing table is Modern Satellite gesture stability and the multi-functional full physical simulation platform developed, and its principle makes this platform suspension in the air by spraying pressurized air, and thus whole system has the little advantage of damping.We, when calculating disturbance torque, must know its angular velocity and angular acceleration, so the height of its outer corner measurement precision directly affects the physical simulation effect of satellite attitude control system.

There is cost for outer corner measurement error calibration method in the actual and existing document of current domestic project high, algorithm complexity, is restricted in high precision applications, does not make full use of existing fine measuring instrument; Or too rely on existing exact instrument, only carried out simple correction, its model is too idealized, and engineering practice effect is bad, angle measurement accuracy is unstable, and compensation effect is poor.

Summary of the invention

There is precision instability, the problems such as compensation effect is poor to solve existing outer corner measurement error calibration method in the present invention, and then provides a kind of air floating table precision measurement error calibration method.

The present invention solves the problems of the technologies described above the technical scheme taked to be:

A kind of single-axle air bearing table precision measurement error calibration method, the specific implementation process of described method is:

Step one: by air floating table adjustment;

Step 2: obtain grating angle reading α with autocollimator and 17 rib body examinations _i(i=1,2 ..., 17); α _i(i=1,2 ..., 17) deduct detection angle β _i(i=1,2 ..., 17), its result equals the angular errors value y of air floating table _i(i=1,2 ..., 17); That is: y _i=α _i-β _i;

β ₀for the initial value chosen according to detailed programs precision;

Step 3: according to formula get x _i=i (i=1,2...17) obtains 16 linearity correction piecewise functions respectively, corrects the grating angle of Computer display; X represents any rotation angle value before air floating table correction, and y represents the modified value of air floating table corner;

Step 4: repeat step 2, the corrected value utilizing step 3 to try to achieve measures new angular errors value z _i(i=1,2 ..., 17); z _i=(α _i-β _i)+y;

Step 5: according to formula obtain harmonic correction function, the grating angle of Computer display is corrected;

Wherein a _i(i=0,1 ..., 8), b _i(i=1,2 ..., 8) be model parameter, ω=0.01095 is quadravalence grating harmonic constant;

Step 6: calculate and consider the modified value y of air floating table corner and the final angular errors value s of harmonic wave correction function _i(i=1,2 ..., 17); s _i=z _i+ z;

Step 7: judge final angular errors value s _i(i=1,2 ..., 17) whether be greater than accuracy requirement, if so, return step 2, otherwise perform step 8;

Step 8, obtains net result, completes single-axle air bearing table precision measurement error correction.

The invention has the beneficial effects as follows:

Air floating table precision measurement error calibration method of the present invention, structure is simple, cost is low, angle measurement accuracy is high.

Provide angle-position precision detection table as follows:

Accompanying drawing explanation

Fig. 1 is the outer corner measurement schematic diagram (in figure: 1-air supporting stage body, 2-rib body, 3-light pipe, 4-grating) in the present invention; Fig. 2 is angular errors correcting process block diagram.

Embodiment

Below in conjunction with accompanying drawing citing, the invention will be further described

Embodiment one: in conjunction with Fig. 1 and 2, the detailed process of the single-axle air bearing table precision measurement error calibration method of present embodiment is as follows:

The detection autocollimator of angle error and 17 rib bodies detect.First, air floating table installs 17 rib bodies and fixes, adjustment rib body and light pipe system, make light pipe aim at a workplace of rib body, then rotation axis system detects (detection angle near selected detection angle successively β ₀initial value for choosing according to detailed programs precision).Micro-adjusting mechanism on adjustment axle, making the reading of light pipe as far as possible little at every turn, measure 17 points, is that benchmark rotates air floating table successively with angle measuring system, reads the reading α of computing machine _i(i=1,2 ..., 17), try to achieve angular errors.

Step one: by air floating table adjustment;

Step 2: the grating 4 angular readings α recorded with autocollimator and 17 rib bodies 2 _i(i=1,2 ..., 17); α _i(i=1,2 ..., 17) deduct detection angle β _i(i=1,2 ..., 17), its result equals the angular errors value y of air floating table _i(i=1,2 ..., 17); That is: y _i=α _i-β _i;

β ₀for the initial value chosen according to detailed programs precision;

Step 3: set up error linear calibration model (wherein y is the error angle measured), gets x _i=i (i=1,2...17) carries out linear interpolation correction, derives linear interpolation formula

According to formula get x _i=i (i=1,2...17) obtains 16 linearity correction piecewise functions respectively, corrects the grating angle of Computer display; X represents any rotation angle value before air floating table correction, and y represents the modified value of air floating table corner;

Step 4: repeat step 2, the corrected value utilizing step 3 to try to achieve measures new angular errors value z _i(i=1,2 ..., 17); z _i=(α _i-β _i)+y;

Step 5: set up error harmonic correction model wherein a _i(i=0,1 ..., 8), b _i(i=1,2 ..., 8) be model parameter, w=0.01095 is quadravalence grating harmonic constant;

Definition solve system of equations below,

Wherein

Obtain a _i(i=0,1 ..., 8), b _i(i=1,2 ..., 8);

According to formula obtain harmonic correction function, the grating angle of Computer display is corrected;

Wherein a _i(i=0,1 ..., 8), b _i(i=1,2 ..., 8) be model parameter, ω=0.01095 is quadravalence grating harmonic constant;

Step 6: calculate and consider the modified value y of air floating table corner and the final angular errors value s of harmonic wave correction function _i(i=1,2 ..., 17); s _i=z _i+ z;

Step 7: judge final angular errors value s _i(i=1,2 ..., 17) whether be greater than accuracy requirement, if so, return step 2, otherwise perform step 8;

Step 8, obtains net result, completes single-axle air bearing table precision measurement error correction.

Claims (1)

1. a single-axle air bearing table precision measurement error calibration method, is characterized in that: the specific implementation process of described method is:

Step one: by air floating table adjustment;

Step 2: record grating (4) angular readings α with autocollimator and 17 rib bodies (2) _i(i=1,2 ..., 17); α _i(i=1,2 ..., 17) and deduct detection angle β _i(i=1,2 ..., 17), its result equals the angular errors value y of air floating table _i(i=1,2 ..., 17); That is: y _i=α _i-β _i;

β ₀for the initial value chosen according to detailed programs precision;

Step 3: according to formula get x _i=i (i=1,2 ... 17) obtain 16 linearity correction piecewise functions respectively, the grating angle of Computer display is corrected; X represents any rotation angle value before air floating table correction, and y represents the modified value of air floating table corner;

Step 4: repeat step 2, the corrected value utilizing step 3 to try to achieve measures new angular errors value z _i(i=1,2 ..., 17); z _i=(α _i-β _i)+y;

Step 5: according to formula obtain harmonic correction function, the grating angle of Computer display is corrected;

Wherein a _i(i=0,1 ..., 8), b _i(i=1,2 ..., 8) and be model parameter, ω=0.01095 is quadravalence grating harmonic constant;

Step 6: calculate and consider the modified value y of air floating table corner and the final angular errors value s of harmonic wave correction function _i(i=1,2 ..., 17); s _i=z _i+ z;

Step 7: judge final angular errors value s _i(i=1,2 ..., 17) whether be greater than accuracy requirement, if so, return step 2, otherwise perform step 8;

Step 8, obtains net result, completes single-axle air bearing table precision measurement error correction.