CN104515481A - Device and method for measuring planeness of large-diameter torus - Google Patents

Abstract

The invention discloses a device and a method for measuring planeness of a large-diameter torus, relates to measuring technology in the field of machining mounting and adjusting detection and solves the problem that an existing torus planeness measuring device is complex in structure and limited in use and the problem that an existing measuring method is large in measuring error caused by low measuring accuracy and the like. The device comprises a precise turntable, an internal focusing light tube, a turnplate leveling mechanism, a measuring rod and a CCD (charge coupled device) detector. The method includes utilizing the internal focusing light tube to image an optical fiber point light source above the measured torus; enabling the precise turntable to drive an image point of the point light source to rotate for drawing a circle in space; using the CCD detector to receive the image point of the point light source by taking a plane where the circle is positioned as a base; measuring distance between a measured point and the base plane according to target missing distance; calculating to acquire planeness of the measured torus through data processing. The device and the method are high in measuring accuracy, simple in data processing, convenient in operation, high in efficiency, low in cost and suitable for detection of planeness of large-size ring members.

Description

Measure the device and method of large diameter circle facial plane degree

Technical field

The present invention relates to the measuring technique that machining debugs detection field, be specifically related to a kind of apparatus and method that large diameter circle facial plane degree is detected.

Background technology

The high-acruracy survey of flatness is the important step that machining debugs in testing process, the diameter of large scale circular ring type part is all several meters of magnitudes, the accurate measurement of its flatness is a difficult point always, and the method used in producing at present has level meter method, many gauge heads error separation method, three-dimensional coordinates measurement method, level surface method, rotation of rotary table method, 3 analyzer methods and micr-alignment telescope method etc.

Wherein level meter method is most widely used, and owing to adopting pitch point-to-point measurement, measuring speed is too slow, and many by external interference factor, the application that this method is the most ripe is in addition mainly for the large plane of middle atresia, so that the division of examination network; Many gauge heads partition method can obtain micron-sized high precision, but owing to using sensor many, needs data volume to be processed large, complex structure, and operation inconvenience, uses limited; Three-dimensional coordinates measurement method precision reduces along with the increase of measurement size, the maximum annulus part can only measuring diameter about two meters of mobile bridge type coordinate measuring machine, portable coordinate measurement machine (articulated arm or laser tracker) can measure large-scale part, but precision is lower, expensive; Level surface method system hardware configuration is complicated, and adopting a measuring process needs to wait for liquid level stabilizing, and efficiency is low, greatly affected by environment, low precision; Rotation of rotary table method is due to by the impact of measuring cantilever stiffness, lower to the measuring accuracy of large scale annulus; 3 analyzer methods are researched and developed for the measurement of planeness of electro-optic theodolite turntable shaft carrier ring specially, but due to the impact of 3 analyzer stiffness by itself, only about one meter in diameter and below neck collar on well applied; Micr-alignment telescope coordinates pentaprism to rotate formation reference plane, the method is relatively applicable to the measurement of annulus part flatness, but adopts parallel plate micrometer principle reading, during telemeasurement due to it, by the impact of optical system picture element and enlargement factor, measuring error is larger.

Summary of the invention

The present invention is that the measurement mechanism solving existing circular planes degree exists complex structure and uses limited problem, present measuring method is low and cause the problems such as measuring error is large owing to there is measuring accuracy, provides a kind of device and method measuring large diameter circle facial plane degree.

Measure the device of large diameter circle facial plane degree, comprise precise rotating platform, interior focusing light pipe, fiber optic point source, leveling turntable mechanism, measuring staff and ccd detector; Precise rotating platform is placed in leveling turntable mechanism, interior focusing light pipe is fixed on precise rotating platform table top, the rotational axis vertical of described interior focusing light pipe optical axis and precise rotating platform, the turning axle of described precise rotating platform and the center superposition of measured circle anchor ring, described fiber optic point source is connected to the focal position of interior focusing light pipe, the axis being parallel of ccd detector target surface and measuring staff, and measuring staff axis is vertical with measured circle anchor ring, measuring staff head is sphere, and is point cantact with measured circle anchor ring.

Measure the method for large diameter circle facial plane degree, the method is realized by following steps:

Step one, successively measuring staff is placed on the position of measured point described in position, equally spaced mark measured point on measured circle anchor ring, ccd detector is made to receive the picture point of the fiber optic point source of position, different measured point, rotate precise rotating platform, make the picture point of the fiber optic point source of position, described different measured point be zero at the miss distance of ccd detector horizontal direction, and record the miss distance of ccd detector vertical direction;

Step 2, data processing is carried out to the miss distance of the record ccd detector vertical direction described in step one, obtain the error of measured circle anchor ring flatness, realize the detection of the flatness to measured circle anchor ring.

Beneficial effect of the present invention: the present invention innovates improvement on the basis of classic method, overcome the deficiency of classic method, adopt the method for optics and image procossing, use interior focusing light pipe in conjunction with precise rotating platform, the disc formed at Space Rotating with fiber optic point source picture point is for benchmark, receive fiber optic point source picture point with ccd detector and measure its miss distance, calculating the flatness of measured circle anchor ring finally by data processing.The principle of the invention is clear and definite, and structure is simple, and easy to operate, precision is high, practical.The present invention forms reference plane in an optical manner, and precision does not affect by the rigidity of structure; Adopt the distance of the direct measuring basis hot spot of CCD and tested surface, measuring accuracy is high; For the measured circle ring of different-diameter, regulate interior focusing light pipe, fiber optic point source picture point is transmitted to above tested annulus, measure strong adaptability; Site Detection debuging with the Large circular ring instructing rigidity poor can also be carried out simultaneously, its flatness error is met the demands.

Accompanying drawing explanation

Fig. 1 is the device schematic diagram of measurement large diameter circle facial plane degree of the present invention.

In figure: 1, ccd detector, 2, fixed lens group, 3, focusing lens group, 4, fiber optic point source, 5, precise rotating platform, 6, leveling turntable mechanism, 7, measuring staff, 8, tested annulus.

Embodiment

Embodiment one, composition graphs 1 illustrate present embodiment, and measure the device of large diameter circle facial plane degree, this device comprises precise rotating platform 5, interior focusing light pipe, fiber optic point source 4, leveling turntable mechanism 6, measuring staff 7 and ccd detector 1.Interior focusing light pipe is made up of fixed lens group 2 and focusing lens group 3.Precise rotating platform 5 is placed in leveling turntable mechanism 6, and interior focusing light pipe is fixed on precise rotating platform 5 table top, and fiber optic point source 4 is connected to the focal position of interior focusing light pipe, and ccd detector 1 is arranged on measuring staff 7.

Focusing lens group 3 in interior focusing light pipe described in present embodiment can move along optical axis direction, precise rotating platform 5 rotation and measured circle anchor ring 8 center superposition.Interior focusing light pipe optical axis and precise rotating platform 5 rotational axis vertical.Ccd detector 1 target surface and measuring staff 7 axis being parallel, measuring staff 7 axis is vertical with measured circle anchor ring 8, and measuring staff 7 head is sphere, is point cantact with measured circle anchor ring 8.

Embodiment two, present embodiment are the method for the device of the measurement large diameter circle facial plane degree described in embodiment one, and the concrete steps of the method are:

First, regulate interior focusing light pipe before measurement, measuring staff 7 is vertically placed on measured circle anchor ring 8, and ccd detector 1 receives the picture point of fiber optic point source 4, and the position of adjustment focusing lens group 3, makes picture point hot spot minimum.

Secondly, adjust the attitude of precise rotating platform 5, the position of mobile measuring staff 7, make ccd detector 1 equally spaced three diverse locations on measured circle anchor ring 8 receive the picture point of fiber optic point source 4, adjustment precise rotating platform levelling gear 6, makes picture point equal at the miss distance of ccd detector 1 vertical direction.

During measurement, first in the position of the first-class spaced markings measured point of measured circle anchor ring 8, then successively measuring staff 7 is placed on the position θ of measured point _i, rotate precise rotating platform 5, make picture point be zero at ccd detector 1 horizontal direction miss distance, the miss distance y of record ccd detector 1 vertical direction _i.

Finally, measurement data is processed, first measurement data y _ibe launched into Fourier series f (θ _i) carry out frequency analysis, then remove constant term and once item harmonic wave Y ₁, obtain data t _i.

$f\left({\mathrm{\θ}}_i\right)=\frac{a_0}{2}+\underset{k=1}{\overset{\∞}{\mathrm{\Σ}}}(a_k\cos {\mathrm{k\θ}}_i+b_k\sin k{\mathrm{\θ}}_i)$

Wherein:

$a_0=\frac{2}{n}\underset{i=0}{\overset{n-1}{\mathrm{\Σ}}}{y}_i$

$a_k\≈\frac{2}{n}\underset{i=0}{\overset{n-1}{\mathrm{\Σ}}}{y}_i\cos k{\mathrm{\θ}}_i$

$b_k\≈\frac{2}{n}\underset{i=0}{\overset{n-1}{\mathrm{\Σ}}}{y}_i\sin k{\mathrm{\θ}}_i$

Kth time item harmonic function: Y _k=a _kcos k θ _i+ b _ksin k θ _i

$t_i=y_i-\frac{a_0}{2}-Y_1=y_i-\frac{a_0}{2}-a_1\cos {\mathrm{\θ}}_i-b_1\sin {\mathrm{\θ}}_i$

Again to (θ _i, t _i) planar carrying out least squares line fitting, straight-line equation is:

Aθ+Bt+C＝0

Then each point (θ is calculated _i, t _i) to the distance of fitting a straight line:

$D_i=\frac{{\mathrm{A\θ}}_i+{\mathrm{Bt}}_i+C}{\sqrt{A^2+B^2}}$

Last Calculation Plane degree error: Flatness=D _max-D _min.

In formula: y _ifor the miss distance of ccd detector vertical direction, θ _ifor the angle value of measurement point position on anchor ring, a _kfor the coefficient of cosine component in kth time item harmonic function, b _kfor the coefficient of sinusoidal component in kth time item harmonic function; Y _kfor kth time item harmonic function, t _ifor removing constant term and the data once after item after frequency analysis, A, B and C are the coefficient of fitting a straight line, D _ifor each point is to the distance of fitting a straight line, D _maxfor ultimate range, D _minfor minor increment, Flatness is flatness error.

Measuring method of the present invention forms reference plane in an optical manner, and precision does not affect by the rigidity of structure; Adopt the distance of the direct measuring basis hot spot of ccd detector and measured circle anchor ring, measuring accuracy is high; For the measured circle toric optical part of different-diameter, regulate interior focusing light pipe, fiber optic point source picture point is transmitted to the top of measured circle anchor ring, measure strong adaptability; The present invention is applicable to mechanic factory workers, large component assembling construction unit and detects metrological service using.

Claims (5)

1. measure the device of large diameter circle facial plane degree, comprise precise rotating platform (5), interior focusing light pipe, fiber optic point source (4), leveling turntable mechanism (6), measuring staff (7) and ccd detector (1), precise rotating platform (5) is placed in leveling turntable mechanism (6), interior focusing light pipe is fixed on precise rotating platform (5) table top, it is characterized in that, the rotational axis vertical of described interior focusing light pipe optical axis and precise rotating platform (5), the turning axle of described precise rotating platform (5) and the center superposition of measured circle anchor ring (8), described fiber optic point source (4) is connected to the focal position of interior focusing light pipe, the axis being parallel of ccd detector (1) target surface and measuring staff (7), measuring staff (7) axis is vertical with measured circle anchor ring (8), measuring staff (7) head is sphere, and be point cantact with measured circle anchor ring (8).

2. the device of described measurement large diameter circle facial plane degree according to claim 1, it is characterized in that, described interior focusing light pipe is made up of fixed lens group (2) and focusing lens group (3); Focusing lens group (3) in described interior focusing light pipe moves along optical axis direction.

3. the method for the device of measurement large diameter circle facial plane degree according to claim 1, it is characterized in that, the method is realized by following steps:

Step one, successively measuring staff (7) is placed on the position of measured point described in the upper position, equally spaced mark measured point of measured circle anchor ring (8), ccd detector (1) is made to receive the picture point of the fiber optic point source (4) of position, different measured point, rotate precise rotating platform (5), make the picture point of the fiber optic point source (4) of position, described different measured point be zero at the miss distance of ccd detector (1) horizontal direction, and record the miss distance of ccd detector (1) vertical direction;

Step 2, data processing is carried out to the miss distance of record ccd detector (1) vertical direction described in step one, obtain the error of measured circle anchor ring (8) flatness, realize the detection of the flatness to measured circle anchor ring.

4. the method for measurement large diameter circle facial plane degree according to claim 3, it is characterized in that, the detailed process obtaining flatness error in step 2 is: first measurement miss distance data are launched into Fourier series and carry out frequency analysis, secondly, removal constant term and once item harmonic wave, again, carry out least square fitting, finally calculate flatness error.

5. the method for the measurement large diameter circle facial plane degree according to claim 3 or 4, it is characterized in that, before step, also comprise the adjustment to interior focusing light pipe, measuring staff (7) is vertically placed on measured circle anchor ring (8), ccd detector (1) receives the picture point of fiber optic point source (4), and the position of adjustment focusing lens group (3), makes picture point hot spot minimum; To the adjustment of precise rotating platform (5) attitude, the position of mobile measuring staff (7), ccd detector (1) is made to receive the picture point of fiber optic point source (4) at the equally spaced diverse location of the upper mark of measured circle anchor ring (8), adjustment leveling turntable mechanism (6), makes picture point equal at the miss distance of ccd detector (1) vertical direction.