CN106425691A - Laser interference principle-based precise main shaft rotation precision detecting device and method - Google Patents

Abstract

The invention discloses a laser interference principle-based precise main shaft rotation precision detecting and analyzing method. A precise main shaft rotation precision detecting light path comprises a box body which is used for mounting required instruments, a laser transmitter which is mounted in the box body, four optical convex lenses, a half transparent and half reflecting mirror, a reference ball and a CCD camera; part laser beams emit out from a circular hole in a square box and are projected on a target ball; the target ball is mounted on a precise main shaft through an extending rod. A laser interference pattern which is acquired by the CCD camera is analyzed through an analysis principle to acquire the rotating speed and a three-directional displacement error of the precise main shaft. The laser interference principle-based precise main shaft rotation precision detecting and analyzing method is conveniently used for engineering detection; error separation is not required; the rotating speed, and the axial and radial displacement errors of the precise main shaft can be detected simultaneously; moreover, the detection precision reaches nano scale.

Description

Measuring of Axis Rotating Accuracy detection means and method based on laser interference principle

【Technical field】

The invention belongs to Measuring of Axis Rotating Accuracy test analysis field, is related to a kind of precision based on laser interference principle Spindle rotation precision detection device and method.

【Background technology】

Accurate main shaft is the important composition part of high-grade, digitally controlled machine tools, and its precision property has important shadow to machine tooling ability Ring.And due to the foozle of characteristic face and the rotating accuracy of accurate main shaft for detection very close to, it usually needs use one Fixed means realize error separate, obtain more real rotating accuracy result.For circular runout, multiple sensings are generally adopted Being detected in device difference angle, and then gained signal is processed with mathematical method, is realized error separate.Main method just has Friendship method, line-of-sight course etc..And for axial float, generally measured using single-sensor.

Current Measuring of Axis Rotating Accuracy detection method is suffered from the drawback that：

1) be reduce mismachining tolerance impact, for detect characteristic face requirement on machining accuracy very high；

2) how using electric capacity or eddy current displacement sensor, detection is affected by tested surface material；

3) it is the linear measurement that ensures sensor, has very high wanting to tested surface diameter and sensor to the distance of tested surface Ask；

4) circular runout adopts FUSION WITH MULTISENSOR DETECTION, and extension sensor line should meet at a bit, and for carrying out error separate, passes Sensor angle requirement is higher, sensor great difficulty is installed；

5) main shaft rotary speed needs individually to detect, is unfavorable for Synchronization Analysis.

【Content of the invention】

It is an object of the invention to overcoming above-mentioned shortcoming of the prior art, a kind of essence based on laser interference principle is proposed Close spindle rotation accuracy determination method.

For reaching above-mentioned purpose, the present invention is employed the following technical solutions and is achieved：

Based on the Measuring of Axis Rotating Accuracy detection means of laser interference principle, including casing and target ball；Target ball is by even Bar is on tested accurate main shaft；The lasing light emitter that stable one-wavelength laser can occur and interference testing system are installed in casing System；The connecting rod of target ball is parallel with the laser beam axis for projecting from casing, and the centre of sphere of target ball is near laser beam convergent point.

The present invention is further improved by：

The interference testing system includes that the first extender lenses being set in turn on lasing light emitter emergent light optical axis, second are expanded Bundle lens, the first plus lens and semi-transparent semi-reflecting lens, arrange reference sphere in the reflected light light path of semi-transparent semi-reflecting lens side, its convergence Point is overlapped with the centre of sphere of reference sphere, and opposite side arranges the second plus lens；Semi-transparent semi-reflecting lens will be through the first plus lens transmission The light part for coming over reflexes to reference sphere, and another part is projected to target ball through the circular hole on casing along emergent light optical axis transmission； Reflected light of second plus lens by reference sphere with target ball is converged, and spherical wave is converted into plane wave.

The dead astern of second plus lens is provided for measuring the CCD camera of echo interference image.

A kind of Measuring of Axis Rotating Accuracy detection method based on laser interference principle, comprises the following steps：

1) casing being finely tuned, makes the laser beam convergent point of injection that target ball coordinate system is always positioned in accurate main shaft rotary course A certain quadrant in and close proximity to the centre of sphere, gather interference image using CCD camera, analysis obtains target ball errors of centration displacement；

2) control accurate main shaft rotation, record target ball center motion track；

3) rotary speed of analysis target ball center motion track acquisition accurate main shaft and axially and radially displacement error.

Which is further improved by：

The step 1) concrete grammar as follows：

If air refraction is n=1, the radius of reference sphere and target ball is R, after adjustment, target ball center is in target ball coordinate system In coordinate be δ=(δ_x, δ_y, δ_z)；Target ball coordinate system is the coordinate system that initial point is located at outgoing laser beam convergent point；In target ball The light at certain point P (x, y, z) place, due to the relative R very little of displacement, incident illumination is negligible with the angle of reflected light, is considered as weight Close；Can obtain in P point and reference sphere corresponding point position, after reflection, the optical path difference of light is：

Additionally, due to P point on target ball sphere, there is geometrical relationship：

x²+y²+z²=R²(2)

Setting up measurement coordinate in CCD camera is used for measuring interference image data；If the reference sphere centre of sphere converges saturating to second The distance of mirror is d, then CCD camera each point corresponding with sphere, and the amplification coefficient of coordinate figure is：

Simultaneous formula (1), (2), (3), obtain the coordinate figure (x of each point in measurement coordinate system_c, y_c, z_c), optical path difference Δ and target Displacement of ball error (δ_x, δ_y, δ_z) relation be：

When optical path difference is for the integral multiple of wavelength X, interferes and bright fringess are obtained, a series of ellipses are seen to be by relational expression； Light beam convergent point is calculated in target ball coordinate according to the relation between three nature parameters of interference image and each coefficient of equation Coordinate (δ in system_x, δ_y, δ_z), i.e. the position of the target ball centre of sphere.

Three nature parameters for relating to image are ratio of long axis to short axis, the short-axis direction angle and two of interference image bright fringess Level bright fringess spacing.

The step 3) concrete grammar as follows：

Fundamental frequency as accurate main shaft speed that track in xOy plane project 3-1) is extracted；

Minimum envelop circle that track in xOy plane project, the radial displacement error of its a diameter of accurate main shaft 3-2) are done；

Track projection on z-axis 3-3) is done, and its length is accurate main shaft axial float.

Compared with prior art, the invention has the advantages that：

The present invention obtains rotating speed and radial and axial displacement error using the interference image of spherical wave, analysis；Using interference Image Global Information, substantially reduces to detection faces requirement on machining accuracy；Optical maser wavelength is not affected by reflecting surface material, to tested Facestock matter no requirement (NR)；And optical maser wavelength has good concordance and stability, measurement has good linear characteristic.The present invention As the method is analyzed using the Global Information of interference image, the basic size for ensureing detection faces is only required, to detection faces Requirement on machining accuracy substantially reduce, while also reducing the preservation maintenance requirement of equipment；Material, size to detection faces Requirement is low, eliminates the operation such as transducer calibration, makes test job more simple and convenient, and the scope of application is also more extensive；The present invention The rotating speed of accurate main shaft and radial and axial displacement error are detected simultaneously can, it is to avoid asynchronous etc. between multisensor is asked Topic；Finally, the present invention is without the concern for the position relationship between multiple sensors, and without error separate is carried out, measurement is more Accurately.

【Description of the drawings】

Fig. 1 is the Measuring of Axis Rotating Accuracy detection index path based on laser interference principle；

Fig. 2 is optical path difference schematic diagram；

Fig. 3 is interference fringe schematic diagram；

Fig. 4 is target ball central motion track schematic diagram；

Fig. 5 is radial displacement error assessment method schematic diagram；

Fig. 6 is axial float evaluation methodology schematic diagram.

Wherein：1- target ball；2- reference sphere；3- semi-transparent semi-reflecting lens；4- casing；5- lasing light emitter；The first extender lenses of 6-；7- Two extender lenses；The first plus lens of 8-；9-CCD camera；The second plus lens of 10-.

【Specific embodiment】

Below in conjunction with the accompanying drawings the present invention is described in further detail：

Referring to Fig. 1, Measuring of Axis Rotating Accuracy detection means of the present invention based on laser interference principle, including 4 He of casing Target ball 1.Casing 4 is fixed in space, is provided with laser and occurs and interference testing system in casing 4；Laser transmitting system includes Lasing light emitter 5, can occur stable one-wavelength laser, and interference testing system includes, the first extender lenses 6, the second extender lenses 7, First plus lens 8, semi-transparent semi-reflecting lens 3, reference sphere 2, the second plus lens 10, CCD camera 9；First extender lenses 6, second The laser beam that extender lenses 7 occur to lasing light emitter 5 has collimator and extender to act on；Laser beam after adjustment is entered by the first plus lens 8 Row is converged, and is changed by plane wave and is formed spherical wave；Spherical wave passes through semi-transparent semi-reflecting lens 3, and a part reflexes to reference sphere 2, converges Point is overlapped with the centre of sphere, and another part is projected to target ball by the circular hole on casing 4；Second plus lens 10 and the first plus lens 8 parameters are consistent and symmetrical with regard to semi-transparent semi-reflecting lens 3, and reflected light that can be by reference sphere 2 with target ball 1 is converged, and spherical wave is changed shape Become plane wave；CCD camera 9 is located at the dead astern of the second plus lens 10, measures the interference image of echo.

Target ball 1 is by connecting rod on tested accurate main shaft；The connecting rod of target ball 1 and the laser beam for projecting from casing 4 Diameter parallel, and the centre of sphere of target ball 1 is near laser beam convergent point.

As shown in Fig. 2 in target ball certain point P (x, y, z) place light, due to the relative R very little of displacement, incident illumination with anti- The angle for penetrating light is negligible, is considered as coincidence.So optical path difference is the twice of a current light path segment distance fewer than original light path.

As shown in figure 3, when being that target ball center has displacement error, the image of the interference bright fringess for obtaining in CCD camera, be A series of ellipses.

As shown in figure 4, be the possible movement locus in target ball center, positioned at the Ith quadrant of coordinate system.Therefore according to interferogram As three error amounts trying to achieve be on the occasion of.

As shown in figure 5, target ball central motion track is projected in xOy plane, and then obtain minimum envelop circle, round is straight Footpath is exactly accurate main shaft radial displacement error.

As shown in fig. 6, target ball central motion track is projected in z-axis, obtain the length of Projection Line Segment, as essence The axial float of close main shaft.

The invention also discloses a kind of method of testing for detecting Measuring of Axis Rotating Accuracy based on interference image, including following Step：

1) casing being finely tuned, makes the laser beam convergent point of injection that target ball coordinate system is always positioned in accurate main shaft rotary course The Ith quadrant in (also can be positive and negative for determining error displacement in other quadrants) and close proximity to the centre of sphere, using CCD camera Collection interference image, analysis obtains target ball errors of centration displacement.

If air refraction is n=1, the radius of reference sphere and target ball is R, after adjustment, target ball center is in target ball coordinate system In coordinate be δ=(δ_x, δ_y, δ_z).Target ball coordinate system is the coordinate system that initial point is located at outgoing laser beam convergent point.In target ball The light at certain point P (x, y, z) place, due to the relative R very little of displacement, incident illumination is negligible with the angle of reflected light, is considered as weight Close.Can obtain in P point and reference sphere corresponding point position, after reflection, the optical path difference of light is

Additionally, due to P point on target ball sphere, there is geometrical relationship

x²+y²+z²=R²(2)

Setting up measurement coordinate in CCD camera is used for measuring interference image data.If the reference sphere centre of sphere converges saturating to second The distance of mirror 10 is d, then CCD camera each point corresponding with sphere, and the amplification coefficient of coordinate figure is

Simultaneous formula (1), (2), (3), can obtain the coordinate figure (x of each point in measurement coordinate system_c, y_c, z_c), optical path difference Δ and target Displacement of ball error (δ_x, δ_y, δ_z) relation be

When optical path difference is for the integral multiple of wavelength X, interferes and bright fringess are obtained, by relational expression it is seen that a series of ellipse Circle.

According to three nature parameters of interference image (ratio of long axis to short axis of desirable interference image bright fringess, short-axis direction angle, Two-stage bright fringess spacing) and the relation between each coefficient of equation can be calculated coordinate of the light beam convergent point in target ball coordinate system (δ_x, δ_y, δ_z), i.e. the position of the target ball centre of sphere.

2) control accurate main shaft rotation, record target ball center motion track.

3) rotary speed of analysis target ball center motion track acquisition accurate main shaft and axially and radially displacement error.Specifically Analysis method is：

A. the fundamental frequency as accurate main shaft speed that track is projected in xOy plane is extracted；

B. the minimum envelop circle that track is projected in xOy plane, the radial displacement error of its a diameter of accurate main shaft are done；

C. projection of the track in z-axis is done, and its length is accurate main shaft axial float.

Above content technological thought only to illustrate the invention, it is impossible to limit protection scope of the present invention with this, every presses According to technological thought proposed by the present invention, any change that is done on the basis of technical scheme, claims of the present invention is each fallen within Protection domain within.

Claims (7)

1. the Measuring of Axis Rotating Accuracy detection means based on laser interference principle, it is characterised in that including casing (4) and target ball (1)；Target ball (1) is by connecting rod on tested accurate main shaft；It is provided with casing (4) and stable one-wavelength laser can occurs Lasing light emitter (5) and interference testing system；The connecting rod of target ball (1) is parallel with the laser beam axis for projecting from casing (4), and target The centre of sphere of ball (1) is near laser beam convergent point.

2. the Measuring of Axis Rotating Accuracy detection means based on laser interference principle according to claim 1, its feature exists The first extender lenses (6) for including to be set in turn on lasing light emitter (5) emergent light optical axis in, the interference testing system, second Extender lenses (7), the first plus lens (8) and semi-transparent semi-reflecting lens (3), set in the reflected light light path of semi-transparent semi-reflecting lens (3) side Reference sphere (2) is put, its convergent point is overlapped with the centre of sphere of reference sphere (2), opposite side arranges the second plus lens (10)；Semi-transparent semi-reflecting The light part for coming through the first plus lens (8) transmission is reflexed to reference sphere (2) by mirror (3), and another part is along emergent light Optical axis transmission, projects to target ball (1) through the circular hole on casing (4)；Second plus lens (10) is by reference sphere (2) and target ball (1) Reflected light converge, spherical wave is converted into plane wave.

3. the Measuring of Axis Rotating Accuracy detection means based on laser interference principle according to claim 2, its feature exists In the dead astern of the second plus lens (10) is provided for measuring the CCD camera (9) of echo interference image.

4. a kind of Measuring of Axis Rotating Accuracy based on laser interference principle of employing claim 1-3 any one described device Detection method, it is characterised in that comprise the following steps：

1) fine setting casing (4), makes the laser beam convergent point of injection be always positioned at target ball (1) coordinate in accurate main shaft rotary course In a certain quadrant of system and close proximity to the centre of sphere, interference image is gathered using CCD camera (9), analysis obtains target ball (1) center by mistake Difference displacement；

2) control accurate main shaft rotation, record target ball (1) center motion track；

3) rotary speed of analysis target ball (1) center motion track acquisition accurate main shaft and axially and radially displacement error.

5. the Measuring of Axis Rotating Accuracy detection method based on laser interference principle according to claim 4, its feature exists In the step 1) concrete grammar as follows：

If air refraction is n=1, the radius of reference sphere and target ball is R, after adjustment, target ball center is in target ball coordinate system Coordinate is δ=(δ_x, δ_y, δ_z)；Target ball coordinate system is the coordinate system that initial point is located at outgoing laser beam convergent point；A certain in target ball The light at point P (x, y, z) place, due to the relative R very little of displacement, incident illumination is negligible with the angle of reflected light, is considered as coincidence；Energy Access in P point and reference sphere corresponding point position, after reflection, the optical path difference of light is：

$\mathrm{\Δ}=\frac{2({\mathrm{x\δ}}_x+{\mathrm{y\δ}}_y+{\mathrm{z\δ}}_z)}{R}---\left(1\right)$

Additionally, due to P point on target ball sphere, there is geometrical relationship：

x²+y²+z²=R²(2)

Setting up measurement coordinate in CCD camera is used for measuring interference image data；If the reference sphere centre of sphere is to the second plus lens (10) distance is d, then CCD camera each point corresponding with sphere, and the amplification coefficient of coordinate figure is：

$k=\frac{d}{R}---\left(3\right)$

Simultaneous formula (1), (2), (3), obtain the coordinate figure (x of each point in measurement coordinate system_c, y_c, z_c), optical path difference Δ and target ball position Shift error (δ_x, δ_y, δ_z) relation be：

$\frac{{{\mathrm{\δ}}_x}^2+{{\mathrm{\δ}}_z}^2}{k^2}{x}_c^2+\frac{{{\mathrm{\δ}}_y}^2+{{\mathrm{\δ}}_z}^2}{k^2}{y}_c^2+\frac{2{\mathrm{\δ}}_x{\mathrm{\δ}}_y}{k^2}{x}_c{y}_c-\frac{{\mathrm{\ΔR\δ}}_x}{k}{x}_c-\frac{{\mathrm{\ΔR\δ}}_y}{k}{y}_c=({{\mathrm{\δ}}_z}^2-\frac{{\mathrm{\Δ}}^2}{4})R^2---\left(4\right)$

When optical path difference is for the integral multiple of wavelength X, interferes and bright fringess are obtained, a series of ellipses are seen to be by relational expression；According to Relation between three nature parameters of interference image and each coefficient of equation is calculated light beam convergent point in target ball coordinate system Coordinate (δ_x, δ_y, δ_z), i.e. the position of the target ball centre of sphere.

6. the Measuring of Axis Rotating Accuracy detection method based on laser interference principle according to claim 5, its feature exists In three nature parameters for relating to image are that ratio of long axis to short axis, short-axis direction angle and the two-stage of interference image bright fringess are bright Fringe spacing.

7. the Measuring of Axis Rotating Accuracy detection method based on laser interference principle according to claim 4, its feature exists In the step 3) concrete grammar as follows：

Fundamental frequency as accurate main shaft speed that track in xOy plane project 3-1) is extracted；

Minimum envelop circle that track in xOy plane project, the radial displacement error of its a diameter of accurate main shaft 3-2) are done；

Track projection on z-axis 3-3) is done, and its length is accurate main shaft axial float.