CN102126162A - Numerical control machine processing online measurement method - Google Patents

Abstract

The invention discloses a numerical control machine processing online measurement method. The method can realize online measurement of large workpieces. A binocular stereo vision measurement system is combined with a numerical control machine to complete integral measurement of the large workpieces under the traction of the numerical control machine. The method comprises the following steps of: calibrating internal and external parameters of a camera, and combining the measurement system and the numerical control machine; performing translation calibration and rotary calibration to calibrate direction vectors of X-axis and Y-axis of the numerical control machine and rotary matrix R and translation vector T after the measurement system rotates; dragging the measurement system to move by the numerical control machine to perform single view field scanning till traversing all surfaces of a measured workpiece; and finally, performing integral joint according to all view field point cloud data and the reading of a main shaft of the numerical control machine so as to complete integral measurement of the workpiece. The method has the characteristics of flexible use, convenience, high precision and the like, and can be used for online measurement of the large workpieces on an industrial site.

Description

A kind of Digit Control Machine Tool processing On-line Measuring Method

Technical field

The present invention relates to a kind of method of Digit Control Machine Tool processing on-line measurement, this method can be used for industry spot the industrial processes product is carried out the noncontact on-position measure.The invention belongs to field of machine vision.

Background technology

Large-scale workpiece, particularly single piece, because its relative weight is light, the intensity height is applied in a lot of occasions more and more, but because its appearance and size is big, and feature to be measured is many, makes and realize its measurement is very difficult in practice.If utilize contact type measurement, not only can not get highdensity point cloud data, and measure inefficiency, because size greatly also is difficult to measure the integral body of workpiece.Along with science and technology development, non-contact measurement, particularly simple in structure with it based on the measuring method of vision technique, price is low, and characteristics such as measurement efficient height obtain more and more wider application.Because non-cpntact measurement efficient is higher, equipment is simple, is fit to very much be applied to industry spot.

Measuring method based on vision technique has a lot of branches, and wherein based on the processing On-line Measuring Method of technique of binocular stereoscopic vision, it is dense etc. to have high accuracy, noncontact, some cloud.

Conventional online measuring system deficiency is:

(1) generally need be by exterior mechanical equipment, as mechanical arm etc., the traction vision system moves, and has therefore increased the expense of measuring system, and increases the performance etc. that exterior mechanical may have influence on lathe itself in the working site.

(2) existing measurement means for large-scale workpiece needs to paste index point, does not realize the automation of large-scale metrology.

Summary of the invention

Technology of the present invention is dealt with problems and is: propose a kind of Digit Control Machine Tool processing On-line Measuring Method, by combining with lathe, increased the utilization ratio of Digit Control Machine Tool greatly, and solved large scale splicing problem.

Technical solution of the present invention is: a kind of Digit Control Machine Tool processing On-line Measuring Method, it is characterized in that, and may further comprise the steps:

Preparation comprises that the inside and outside parameter of demarcating two video cameras, debugging prepare host computer Survey Software etc., and Survey Software refers to the data processing software for the exploitation of this On-line Measuring Method.

(1) measuring system is installed: the machine tool chief axis cutter is unloaded, and measuring system, promptly the binocular stereo vision measuring system is installed on the main shaft, connects data wire, combines with Digit Control Machine Tool.

(2) translation is demarcated: lathe translation, the X-axis and the direction vector V of Y-axis under the measuring system coordinate system of demarcation Digit Control Machine Tool _x, V _y

The a pair of marker post that is stained with index point is placed on the measured workpiece limit.Two marker post placement directions are respectively along the X-axis and the Y-axis of Digit Control Machine Tool; The control Digit Control Machine Tool along X-axis and the moving several times of y-axis shift, moves and takes two marker posts in the interval respectively, each certain and each moving direction unanimity at interval that moves.Foundation

(Mx _i-Mx _i-1)V _x＝Px _i-Px _i-1

(My _i-My _i-1)V _y＝Py _i-Py _i-1

Wherein, Mx _i, My _iThe X-axis reading and the Y-axis reading of lathe when being the i time shooting index point, Px _i, Py _iIt is the index point coordinate that reappears after the i time shooting.

Difference solving equation group optimal solution, i.e. the direction vector V of Digit Control Machine Tool X-axis and Y-axis under the measuring system coordinate system _xAnd V _y

(3) rotation is demarcated: lathe rotation, postrotational spin matrix R of calibration measurements system and translation vector T.

According to route programming result, the rotation of control lathe, the three-dimensional respectively circular index point that reappears in benchmark visual field and the visual field, rotation back comprises that extract in the center of circle, polar curve mates and three-dimensional reproduction, carries out the three-dimensional point coupling, utilizes quaternary element method, calculates spin matrix R _jWith translation vector T _j, R _jAnd T _jSpin matrix and translation vector for the j time rotation of rotation timing signal measuring system.

(4) the traction main shaft of numerical control machine tool moves to part to be measured with measuring system, treat that main shaft is stable after, workpiece is carried out monoscopic scanning, obtain the monoscopic cloud data;

(5) repeating step (4) obtains all visual field cloud datas until measured workpiece surface traversal is finished, and finishes full-field scanning;

(6) cloud data that obtains according to step (4), (5) splices.

The coordinate system of first visual field of measuring system as world coordinate system, and is spliced each visual field cloud data according to following formula:

$P_W=\underset{i,j}{\mathrm{\Σ}}(R_j\·P_i+T_j+(X_i-X_1)V_x+(Y_i-Y_1)V_y),$

Wherein, P _i, X _i, Y _iBe respectively i cloud data, Digit Control Machine Tool X-axis reading, the Digit Control Machine Tool Y-axis reading of measuring the visual field, R _jAnd T _jBe the spin matrix and the translation vector of j wheel measuring visual field, V _xAnd V _yFor marking direction vector, P _WFor world coordinate system scans cloud data down.

The present invention's advantage compared with prior art is:

(1) the present invention provides a kind of On-line Measuring Method, by combining with Digit Control Machine Tool, improves the processing detection efficiency of whole work-piece.Owing to be on-line measurement, so workpiece needn't unload from lathe after processing, significantly reduces workpiece because the distortion that assembling produces need not part is transported to measuring room, significantly improves and measures efficient.

(2) simple in measurement system structure that the present invention relates to, field calibration method is succinct, can adapt to the industry spot environment fully.Combine with Digit Control Machine Tool, make full use of the advantage of lathe, splicing speed is fast, need not to paste on measured workpiece index point, can obtain fine and close cloud data.

Description of drawings

Fig. 1 is the flow chart of On-line Measuring Method of the present invention.

Fig. 2 demarcates Digit Control Machine Tool direction of motion process schematic diagram for the present invention.One camera is represented measuring system among the figure, and the dotted line of band arrow is the demarcation route of Digit Control Machine Tool traction measuring system among the figure.

Fig. 3 measures route map for the present invention.One camera is represented measuring system among the figure, and the dotted line of band arrow is the measurement route of Digit Control Machine Tool traction measuring system among the figure.

The specific embodiment

For a better understanding of the present invention, below in conjunction with drawings and Examples technical scheme of the present invention is explained in detail.

With reference to accompanying drawing 1, a kind of Digit Control Machine Tool processing On-line Measuring Method comprises following steps:

With measuring system with before Digit Control Machine Tool combines, earlier measuring system is carried out necessary preparation, measuring system refers to the binocular tri-dimensional sense sensor, comprises two video cameras and a projector; The preparation of described necessity comprises the inside and outside parameter of demarcating two video cameras, and host computer Survey Software etc. is prepared in debugging;

1. measuring system is installed, and the main shaft of numerical control machine tool cutter is unloaded, and measuring system is installed on the main shaft, connects data wire, combines with Digit Control Machine Tool.

2. translation is demarcated, lathe translation, the X-axis and the direction vector V of Y-axis under the measuring system coordinate system of demarcation Digit Control Machine Tool _x, V _y

The a pair of marker post that is stained with index point is placed on the measured workpiece limit.Respectively along the X-axis and the Y-axis of Digit Control Machine Tool, and the initial point of two marker posts is in the same angle of measured workpiece to modes of emplacement with reference to 2, two marker post placement directions of accompanying drawing.

Demarcate the path according to translation, the control Digit Control Machine Tool is respectively along X-axis and the moving several times of y-axis shift, and moving method moves and takes two marker posts in the interval with reference to accompanying drawing 2, each certain and each moving direction unanimity at interval that moves.Mobile interval can not be excessive, remains on about 100mm.The X-direction and the Y direction reading of each right moment for camera bed are designated as Mx _iAnd My _i, it is Px that three-dimensional reappears the index point central coordinate of circle that _iAnd Py _i(have a plurality of points, Px in the visual field _iAnd Py _iMay be the set of a plurality of points).

Can obtain according to measurement data:

(Mx _i-Mx _i-1)V _x＝Px _i-Px _i-1

(My _i-My _i-1)V _y＝Py _i-Py _i-1

Utilize Px _iAnd Px _I-1The middle common point that exists calculates.Get i=2,3,4..., then above-mentioned two formulas can be formed equation group respectively, and they all have optimum solution V _xAnd V _y, promptly under the measuring system coordinate system, the direction vector of Digit Control Machine Tool X-axis and Y-axis.

3. rotation is demarcated, lathe rotation, postrotational spin matrix R of calibration measurements system and translation vector T.

Demarcate the path according to rotation, the rotation of control lathe is taken pictures, and obtains rotation back image.The three-dimensional respectively circular index point that reappears in benchmark visual field and the visual field, rotation back comprises that extract in the center of circle, polar curve mates and three-dimensional reproduction, carries out the three-dimensional point coupling, utilizes quaternary element method, calculates spin matrix R _jWith translation vector T _j, get j=2,3,4..., R _jAnd T _jSpin matrix and translation vector for the j time rotation of rotation timing signal measuring system.

4. according to route programming result, the whole route of measuring is with reference to accompanying drawing 3, and the traction main shaft of numerical control machine tool moves to part to be measured with measuring system, treat that main shaft is stable after, workpiece is scanned, obtain the monoscopic cloud data, the cloud data note is made P _i, Digit Control Machine Tool X, Y-axis reading note are made X at this moment _iAnd Y _i

5. repeating step 4 obtains all visual field cloud datas until measured workpiece surface traversal is finished, and finishes full-field scanning;

6. the cloud data that obtains according to step 4,5 splices.

By step 4,5, measuring system travels through whole measured workpiece, obtains all visual field cloud datas.All cloud datas are transformed in the unified coordinate system, promptly finish splicing.Be specially: as world coordinate system, and it is unified according to following formula each visual field cloud data to be carried out coordinate system with the coordinate system of first visual field of measuring system:

$P_W=\underset{i,j}{\mathrm{\Σ}}(R_j\·P_i+T_j+(X_i-X_1)V_x+(Y_i-Y_1)V_y),$

Wherein, P _i, X _i, Y _iBe respectively i cloud data, Digit Control Machine Tool X-axis reading, the Digit Control Machine Tool Y-axis reading of measuring the visual field, R _jAnd T _jBe the spin matrix and the translation vector of j wheel measuring visual field, V _xAnd V _yFor marking direction vector, P _WFor world coordinate system scans cloud data down.

P then _WResult for all visual field cloud data unified coordinate system promptly finishes splicing.

Claims (5)

1. a Digit Control Machine Tool processing On-line Measuring Method is characterized in that, may further comprise the steps:

(1) measuring system is installed: measuring system is installed on the main shaft of numerical control machine tool;

(2) translation is demarcated: the lathe translation, demarcate the direction vector V of Digit Control Machine Tool X-axis and Y-axis _x, V _y

(3) rotation is demarcated: lathe rotation, postrotational spin matrix R of calibration measurements system and translation vector T;

(4) the traction main shaft of numerical control machine tool moves to part to be measured with measuring system, scans, and obtains the monoscopic cloud data;

(5) repeating step (4) is promptly finished full-field scanning until measured workpiece surface traversal is finished;

(6) cloud data that obtains according to step (4), (5) splices.

2. a kind of Digit Control Machine Tool processing On-line Measuring Method according to claim 1, it is characterized in that: described (2) translation is demarcated, and the direction vector V of Digit Control Machine Tool X-axis and Y-axis is demarcated in the lathe translation _x, V _y, accuse that the system Digit Control Machine Tool respectively along X-axis and Y-axis translation several times, moves in the interval and takes marker post, each certain and each moving direction unanimity at interval that moves; Foundation

(Mx _i-Mx _i-1)V _x＝Px _i-Px _i-1

(My _i-My _i-1)V _y＝Py _i-Py _i-1

Wherein, Mx _i, My _iThe X-axis reading and the Y-axis reading of lathe when being the i time shooting index point, Px _i, Py _iIt is the index point coordinate that reappears after the i time shooting;

Difference solving equation group optimal solution V _xAnd V _y, i.e. the direction vector of Digit Control Machine Tool X-axis and Y-axis under the measuring system coordinate system.

3. a kind of Digit Control Machine Tool processing On-line Measuring Method according to claim 1, it is characterized in that: described (2) translation is demarcated, and the direction vector V of Digit Control Machine Tool X-axis and Y-axis is demarcated in the lathe translation _x, V _y, required marker post is placed as: a pair of marker post that is stained with index point is placed on the measured workpiece limit, and two marker post placement directions are respectively along the X-axis and the Y-axis of Digit Control Machine Tool.

4. a kind of Digit Control Machine Tool processing On-line Measuring Method according to claim 1, it is characterized in that: described (3) rotation is demarcated, the lathe rotation, postrotational spin matrix R of calibration measurements system and translation vector T are for benchmark visual field and visual field, rotation back, three-dimensional respectively reproduction circular index point, comprise that extract in the center of circle, polar curve mates and three-dimensional reproduction, carry out the three-dimensional point coupling, utilize quaternary element method, calculate spin matrix R _jWith translation vector T _j, R _jAnd T _jSpin matrix and translation vector for the j time rotation of rotation timing signal measuring system.

5. a kind of Digit Control Machine Tool processing On-line Measuring Method according to claim 1, it is characterized in that: the cloud data that described (6) obtain according to step (4), (5), splice, splicing be coordinate system with first visual field of measuring system as world coordinate system, and each visual field cloud data is spliced according to following formula:

$P_W=\underset{i,j}{\mathrm{\Σ}}(R_j\·P_i+T_j+(X_i-X_1)V_x+(Y_i-Y_1)V_y),$

Wherein, P _i, X _i, Y _iBe respectively i cloud data, Digit Control Machine Tool X-axis reading, the Digit Control Machine Tool Y-axis reading of measuring the visual field, R _jAnd T _jBe the spin matrix and the translation vector of j wheel measuring visual field, V _xAnd V _yFor marking direction vector, P _WFor world coordinate system scans cloud data down.

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