CN108709515B - Method for measuring included angle of rotating shaft - Google Patents

Abstract

The invention discloses a method for measuring the included angle of a rotating shaft, which is characterized in that a reflecting mirror is arranged on a mechanism to be measured, an autocollimator is arranged right in front of the reflecting mirror, the autocollimator is used for collimating the surface of the reflecting mirror, then the rotating shaft is respectively adjusted, the angular components of X and Y axes of a cross-silk image point on an autocollimator CCD are read, the included angle between the adjusted one-dimensional rotating shaft and the autocollimator X axis direction can be obtained according to the fact that the connecting line of the collimated image point and the adjusted image point is necessarily vertical to the adjusted one-dimensional rotating shaft and the trigonometric function relation, in the same way, the included angle between the other-dimensional rotating shaft and the autocollimator X axis direction is obtained, and finally the included angle between the two-dimensional rotating shaft and the autocollimator X. The non-contact measurement method is adopted to realize the measurement of the included angles of the two-dimensional or more than two-dimensional multi-dimensional rotating shafts of the mechanism to be measured, and the measuring precision and the universality are extremely high, the operability is good, the cost is low, and the operation is simple.

Description

Method for measuring included angle of rotating shaft

Technical Field

The invention belongs to the technical field of optical machine assembly and measurement, and particularly relates to a method for measuring an included angle of a rotating shaft.

Background

An angle adjusting mechanism is often used in an optical machine, and the included angle of a mechanical rotating shaft of the adjusting mechanism is required to be within a certain allowable error range. If the difference is exceeded, a linkage effect of the adjusting mechanism occurs. For example, in the magic light device in China, the requirement of the included angle between the deflection rotating shaft and the pitching rotating shaft of a frequency doubling crystal module, a transmission reflector module and the like is 90 degrees, and the requirement of the error is superior to 1 degree. If the error is too large, when one dimension of the rotating shaft of the frequency doubling module or the reflector module is adjusted, the two dimensions of the inverse laser monitored by the spatial filter can be changed, and the field laser collimation is influenced.

Fig. 3 is a schematic diagram illustrating the deviation effect of the yaw rotation axis in the two-dimensional adjustment mechanism, where a straight line AB represents the yaw rotation axis 1, a straight line CD represents the pitch rotation axis, a dotted line EF represents the ideal position of the yaw rotation axis 1, and an original point O is an observation point, and if the deviation angle between the yaw rotation axis 1 and the ideal position is known to be α, if the angle of the yaw rotation axis 1 is adjusted to be Φ, the reflection point at the original point O is moved to N, the following relationships exist:

angle change in the X-axis direction:

angle variation in the Y-axis direction:

it can be known from ① equation and ② equation that the larger the deviation angle α between the yaw rotation axis 1 and the ideal position is, the smaller the X-axis angle component is when adjusting the yaw rotation axis 1 is, and the larger the Y-axis angle component is, and then in the actual use process, the requirement of these optical devices is that when adjusting a certain dimension, the other dimension angle should be kept basically unchanged, so in the production or use process, the rotation axis included angle of the adjusting mechanism needs to be measured to ensure within the precision range, and the precise positioning of the component posture is ensured.

At present, the included angle of a rotating shaft of a known mechanical adjusting mechanism is ensured only by machining and assembling, and generally measurement is not carried out. The principle analysis shows that the included angle of the rotating shaft of the mechanical adjusting mechanism can be measured by a three-coordinate measuring machine, but the central axis of the rotating shaft is constructed by fitting the cylindrical table surface of the rotating shaft for indirect measurement, so that the measurement precision is easily influenced by the form and position tolerance of the rotating shaft of the mechanism to be measured, the precision is limited, and the included angle measurement of the rotating shaft of the adjusting mechanism with the precision adjusting requirement cannot be met. Besides, the three-coordinate measuring machine is high in cost and has working space requirements, the existing measuring method is basically contact-type measurement, interference is easy to occur to a mechanism to be measured, operability is poor, particularly, most of adjusting mechanisms which are completely assembled are closed structures, cross points of the adjusting mechanisms are located in closed spaces, even if a three-coordinate ball head or a target of a laser tracker is adopted, the rotating shaft is difficult to contact, measurement is difficult, and measuring difficulty is high.

Disclosure of Invention

In order to solve the technical problems, the invention provides a method for measuring the included angle of the rotating shaft, which improves the measurement precision and the operability.

In order to achieve the purpose, the technical scheme of the invention is as follows:

the method for measuring the included angle of the rotating shaft is characterized by comprising the following steps:

s1: mounting a reflector on the mechanism to be measured, and collimating the surface of the reflector by using an autocollimator;

s2: after collimation is finished, adjusting one-dimensional rotating shaft of the mechanism to be measured, reading out the angle component of an image point in the direction of the X, Y axis on the auto-collimation CCD, and solving the included angle between the adjusted one-dimensional rotating shaft and the X-axis direction of the auto-collimation instrument;

s3: re-collimating the reflector to restore the one-dimensional rotation axis adjusted in step S2 to the initial position, adjusting another one-dimensional rotation axis, reading out the angular component of the image point in the X, Y axis direction on the auto-collimation CCD, and calculating the included angle between the other one-dimensional rotation axis and the auto-collimation X axis direction

S4: and calculating, namely subtracting the included angles obtained in the steps S2 and S3 to obtain an absolute value, namely the included angle value of the two adjusted rotating shafts.

By adopting the scheme, the autocollimator is used for monitoring the movement track of reflected light imaging in the rotating process of the actuating component driven by the rotating shaft of the piece to be measured, and the principle that the movement track of an image point is necessarily perpendicular to the rotating shaft and the principle of plane and spherical surface reflection far field imaging are applied, so that the measurement precision is high, the error is extremely small, the accuracy of the optical axis of a determined lens is ensured, the universality and the applicability are higher, the measurement of the included angle of the rotating shaft with two or more dimensions can be realized through the thought, and a non-contact measurement method is adopted, so that the operability is good.

In order to further improve the precision of the detection result, the autocollimator is a photoelectric autocollimator.

Preferably, the method comprises the following steps: the autocollimator adopts a pyramid to perform absolute reference point positioning, and the measurement error of the pyramid is less than 3 ″. By adopting the scheme, the accuracy of the absolute reference point of the autocollimator can be improved, and the precision of the measurement result is further improved.

Preferably, the method comprises the following steps: the measurement error of the autocollimator is less than 0.5 ″. By adopting the scheme, the total measurement precision of the pyramid and the pyramid is better than 0.001, and the total measurement error is favorably reduced.

Compared with the prior art, the invention has the beneficial effects that:

the rotating shaft included angle measuring method provided by the invention adopts a non-contact measuring method to realize the measurement of the included angles of the rotating shaft with two or more dimensions of the mechanism to be measured, and has extremely high measuring precision and universality and good operability.

Drawings

FIG. 1 is a schematic diagram of the measurement of the included angle between the deflection rotation and the auto-collimation X-axis direction of the mechanism to be measured in the invention;

FIG. 2 is a schematic diagram of the measurement of the included angle between the pitching rotation and the auto-collimation X-axis direction of the mechanism to be measured in the invention;

FIG. 3 is a schematic diagram of the deviation effect of the deflection rotating shaft in the mechanism to be measured.

Detailed Description

The present invention will be further described with reference to the following examples and the accompanying drawings.

Referring to fig. 1 and fig. 2, in the embodiment, the mechanism to be measured has a dimension adjustment rotating shaft with two dimensions, where a straight line AB represents a yaw rotating shaft 1, and a straight line CD represents apitch rotating shaft 2, and when a measurement is performed, the mirror 3 is mounted on the mechanism to be measured, and when the yaw rotating shaft 1 and thepitch rotating shaft 2 rotate, the mirror 3 can be driven to rotate synchronously together.

After the reflector 3 is installed on the mechanism to be measured, an autocollimator is erected right in front of the reflector 3, wherein the point O is an autocollimation absolute reference point of the autocollimator, the autocollimation attitude is adjusted to collimate the reflector, and the reflected cross-hair image point is superposed with the position O.

Then adjusting the deflection rotating shaft 1 of the mechanism to be measured, moving the cross image point from the point O to the point P, and reading the angle components of the point P in the direction of the X, Y axis on the autocollimator to be β₀、θ₀By movement ofThe relationship known as OP ⊥ AB can be obtained from the trigonometric function relationship:

α angle between the deflection rotating shaft 1 and the X axis₀＝arctan(tanβ₀/tanθ₀).........③

Similarly, as shown in fig. 3, after the deflection rotating shaft 1 is reset, thepitching rotating shaft 2 of the mechanism to be measured is adjusted, the cross image point moves from the position O to the point Q, and the angular component β of the point Q in the direction of the X, Y axis is read₁、θ₁From the kinematic relationship, OQ ⊥ CD is known, and from the trigonometric function relationship:

angle α betweenpitch rotation axis 2 and X-axis₁＝arctan(tanβ₁/tanθ₁)...............④

As can be seen from the angle relationship in the figure, the included angle α between the deflection rotating shaft 1 and the X-axis direction of the autocollimator₀The difference between the included angle of thepitching rotating shaft 2 and the X-axis direction of the autocollimator is the included angle α between the deflection of the piece to be tested and the pitching rotating shaft₁Therefore, the included angle ψ between the yaw rotation axis 1 and the pitch rotation axis can be obtained according to the expressions ③ and ④:

ψ＝|α₀-α₁|＝|arctan(tanβ₀/tanθ₀)-arctan(tanβ₁/tanθ₁)|

similarly, according to the method, the included angle between the rotating shafts with any two dimensions can be measured, whether the included angle meets the design requirements is determined in sequence, the measuring method is adopted to sample and measure the included angles of the frequency doubling module and the pitching two-dimensional rotating shaft of the optical assembly of the terminal of the magic light device, and the measuring results are shown in the table I:

watch 1

The above table shows that the included angles of the rotating shafts of a plurality of samples can be normally measured by the above measuring method, the operability of the measuring method is fully verified, the included angles between the deflection rotating shaft and the pitching rotating shaft of the extracted sample meet the design requirements, the measuring result is accurate to 0.001 degrees, which shows that the measuring precision is high, the accuracy of the measuring result of the measuring method is further verified, in the measuring process, attention needs to be paid to realignment and reset after the measurement of the included angle between one rotating shaft and the X-axis direction is completed, and then the measurement of the included angle between the next one-dimensional rotating shaft and the X-axis direction is performed.

In the invention, in order to improve the measurement accuracy and the operability, the adopted autocollimator is a photoelectric autocollimator with the measurement accuracy better than 0.5 ", and the pyramid with the measurement accuracy better than 3" is adopted for positioning the absolute reference point, so that the measurement accuracy is further improved, the operation is simple, the implementation cost is low, and the autocollimator can be particularly used for the inspection of the previous mechanical assembly process so as to adjust and calibrate the mechanical rotating shaft which is not assembled in place in time and improve the qualification rate of related products.

In addition, the present application is characterized in that the autocollimator can only measure the angles (i.e. the yaw and pitch angles) of the planes (XZ, YZ) of the optical axes, but in the present application, the feature that the connection line of the collimated image point and the adjusted image point must be perpendicular to the adjusted one-dimensional rotation axis is utilized, and the rotation axis included angle of the plane (XZ, YZ) of the optical axes measured by the autocollimator is utilized to calculate the rotation axis included angle of the plane (XY) by means of trigonometric function relationship.

Secondly, the final execution part on the rotating shaft mechanism is measured by the method, all the intermediate mechanical transmission links are included, and the measured result can reflect the mechanical motion performance of the measured adjusting structure more accurately, truly and reliably.

Finally, it should be noted that the above-mentioned description is only a preferred embodiment of the present invention, and those skilled in the art can make various similar representations without departing from the spirit and scope of the present invention.

Claims (4)

1. A method for measuring the included angle of a rotating shaft is characterized by comprising the following steps:

s1: a reflector (3) is arranged on the mechanism to be measured, and the surface of the reflector (3) is collimated by using an autocollimator;

s2, after the collimation is finished, adjusting one-dimensional rotating shaft of the mechanism to be measured, and reading out the angular components of the image point on the auto-collimation CCD in the X, Y axial direction to be β respectively₀、θ₀And calculating the included angle between the adjusted one-dimensional rotating shaft and the X-axis direction of the autocollimator to be α according to the motion relation and the trigonometric function relation₀＝arctan(tanβ₀/tanθ₀)；

S3, re-collimating the reflector, restoring the one-dimensional rotation axis adjusted in step S2 to the original position, adjusting the other one-dimensional rotation axis, and reading out the angle components of the image point in the X, Y axis direction on the auto-collimation CCD to be β₁、θ₁And the included angle α between the other one-dimensional rotation shaft and the X-axis direction of the autocollimator is obtained according to the corresponding motion relation and trigonometric function relation₁＝arctan(tanβ₁/tanθ₁)；

S4, calculating, namely subtracting the included angles obtained in the steps S2 and S3 to obtain the absolute value of the value which is the included angle value psi of the two adjusted rotating shafts, wherein the absolute value of the value is phi α₀-α₁|。

2. The method for measuring the included angle of the rotating shaft according to claim 1, wherein: the autocollimator is a photoelectric autocollimator.

3. The method for measuring the included angle of the rotating shaft according to claim 1, wherein: the autocollimator adopts a pyramid to perform absolute reference point positioning, and the measurement error of the pyramid is less than 3 ″.

4. The method of claim 3, wherein: the measurement error of the autocollimator is less than 0.5 ″.

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