JP2014106167A - Laser projection method and laser projection device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method and a device that not only project design information on a workpiece, using a laser beam, but also easily perform a comparative judgement of the design information with a machining result on the workpiece.SOLUTION: The present invention comprises: a first step of irradiating a workpiece serving as a measurement object with a laser beam from a laser projection part, and controlling a plurality of mirror angles; a second step of photographing the workpiece by a three-dimensional camera, extracting a contour of the workpiece and calculating a three-dimensional coordinate; a third step of comparing the three-dimensional coordinate of the workpiece contour calculated in the second step with the mirror angle and calculating a position relation between the laser projection part and the workpiece; and a fourth step of performing coordinate transformation of CAD data information on the basis of the position relation between the laser projection part and the workpiece calculated in the third step, and drawing CAD data onto the workpiece from the laser projection part.

Description

  The present invention relates to a laser projection method and a laser projection apparatus.

  Machining by NC (Numerical Control) machine automatically proceeds according to NC program. Once machining starts, machining according to the NC program is advantageous from the viewpoint of improving machining efficiency, etc., but if there is a mistake in the NC program, machining proceeds without noticing the mistake. There are challenges. In addition, in order to perform accurate processing, the operator of the processing machine may input a correction value during the processing. In this case, if an incorrect value is input, the incorrect processing is performed as it is. There is a risk. In addition, it is necessary to check whether all drawing instruction parts are processed accurately after all the processing is completed. There is a risk of missing a processed part.

  In response to these problems, a method and apparatus for confirming whether or not a design instruction position is processed according to a design instruction by projecting design information onto a workpiece with a laser beam and confirming a laser locus projected by a person. Has been proposed.

  For example, Kaufman et al. In US Pat. No. 6,547,397 (Patent Document 1) describes a laser drawing apparatus that scans a laser beam with two galvanometer mirrors. Similarly, Kaufman et al., In US Pat. No. 7,306,339 (Patent Document 2), projects a laser beam of a laser drawing apparatus onto a characteristic part of a work and spreads from the characteristic part of the work. By detecting the reflected laser beam, it is possible to grasp the positional relationship between the workpiece and the laser drawing device by grasping the position of the characteristic part of the workpiece (reference point on the workpiece), and to provide design information etc. on the workpiece. Describes how to draw.

US Pat. No. 6,547,397 U.S. Patent No. 7,306,339

  However, in the techniques described in Patent Documents 1 and 2, it is necessary for a person to judge the laser projection result with his / her eyes, and the judgment can be made as long as the machining omission is judged, but whether or not the machining position is correct. It is difficult to accurately determine whether or not the processing dimensions are correct.

SUMMARY OF THE INVENTION An object of the present invention is to provide a method and apparatus that not only projects design information onto a workpiece using a laser beam, but also makes it easy to make a comparative judgment between the design information and a machining result on the workpiece. is there.

  The present invention includes a first step of controlling a plurality of mirror angles and irradiating a laser to a workpiece to be measured from a laser projection unit, and imaging the workpiece with a stereo camera, and extracting the outline of the workpiece. A second step of calculating a three-dimensional coordinate, a three-dimensional coordinate of the workpiece contour calculated in the second step, and the mirror angle are compared to determine a positional relationship between the laser projection unit and the workpiece. And a fourth step of converting CAD data information based on the positional relationship between the laser projection unit and the workpiece obtained in the third step, and rendering CAD data from the laser projection unit to the workpiece. It is characterized by providing.

  According to the present invention, it is possible to provide a method and apparatus that not only projects design information onto a workpiece using a laser beam, but also makes it easy to compare and determine the design information and the machining result on the workpiece. is there.

It is a figure which shows the system configuration | structure in this invention. It is a work that has been subjected to round hole machining. It is a figure which shows a mode that design information was projected on the workpiece | work before the process in this invention. It is a figure which shows a mode that design information was projected on the state in the middle of the round hole processing in this invention. It is a figure which shows a mode that the cross character line was projected on the punch trace in this invention. It is a figure which shows a mode that the crossed line was projected on the ruled mark start point and ruled mark end point position in this invention. It is a figure explaining the procedure which compares the real outline and projection outline in this invention. It is a figure explaining the definition of the remaining amount in this invention. It is a figure explaining the definition of deviation | shift amount in this invention. It is a figure explaining the image processing algorithm for extracting a circular outline in this invention. It is a figure which shows a mode that the extraction result of the circular outline in this invention was superimposed and displayed on the stereo camera image. It is a figure which shows a mode that only the desired outline is selected from the result of having overlapped and displayed the extraction result of the circular outline in this invention on a stereo camera image. It is a figure which shows a mode that the character output teaching is carried out on the workpiece | work in the present invention. In the present invention, the state of teaching the deviation amount calculation result on the workpiece is shown. It is a figure explaining the procedure for grasping | ascertaining the positional relationship of the stereo camera in this invention, a workpiece | work, and a laser projector. It is a figure which shows a mode that the calculation result of the laser bright spot three-dimensional coordinate in this invention was displayed on the display. It is a figure explaining the procedure (software operation) for calculating the three-dimensional coordinate of the circular reference | standard marker or projection laser luminescent spot in this invention. It is another figure explaining the procedure (software operation) for calculating the circular reference marker in this invention, or the three-dimensional coordinate of a projection laser bright spot. It is a figure explaining the procedure (software operation) for calculating the three-dimensional coordinate of the reference | standard position (characteristic shape) of the workpiece | work in this invention. It is a figure which shows a mode that the result which calculated | required the reference position of the workpiece | work with the stereo camera in this invention was displayed on the display. It is a figure which shows a mode that the result of having calculated | required the reference position of the workpiece | work with the stereo camera in this invention from the laser projection part was displayed on the display.

  The present invention relates to a method for drawing design information on a workpiece using a laser beam. Embodiments of the present invention will be described below with reference to FIGS.

  FIG. 1 shows the overall configuration of a laser projection system with a coordinate detection function in the present invention. The laser source 1 is connected to the laser control unit 10, and power is supplied from the laser power source 23 via the laser control unit 10. Further, oscillation and stop are performed in accordance with a command from the mirror position instruction / detection unit 15. As a specific example, for example, when drawing two circles, while moving from the first circle to the second circle, the laser oscillation is stopped and the two circles are individually To be drawn.

  The laser beam 200 oscillated from the laser source 1 is focused at a desired distance by the focusing lens 3. In order to focus the beam at a desired distance, the focusing lens 3 is mounted on a linear motion stage 2 that linearly moves in the optical axis direction. The position of the linear motion stage 2 is controlled by the linear motion stage control unit 11. Specifically, the position of the linear motion stage is calculated by the linear motion stage position instruction / detection unit 14 so that the laser beam is focused at a laser drawing position determined by the CAD data conversion unit 21, which will be described later. The linear motion stage is controlled to move to the calculated position. The linear motion stage 2 is supplied with electric power from the motor driving power source 25 via the linear motion stage control unit 11. The linear motion stage control unit 11 is also supplied with power from the circuit power supply 24.

  The focused beam 201 emitted from the focusing lens 3 is projected onto the workpiece via the first galvanometer mirror 4 and the second galvanometer mirror 5. The angles of the first galvanometer mirror 4 and the second galvanometer mirror 5 are controlled by the first angle control unit 12 and the second angle control unit 13, respectively. Specifically, the mirror position instruction / detection unit 15 uses a first angle and a second angle so that the focused beam 201 is directed to a laser drawing position determined by the CAD data conversion unit 21 described later. The angle is calculated, and the first galvanometer mirror 4 and the second galvanometer mirror 5 are controlled to rotate to the calculated angle. The first galvanometer mirror 4 and the second galvanometer mirror 5 are supplied with electric power from the motor driving power supply 25 via the first angle control unit 12 and the second angle control unit 13. The first angle control unit 12 and the second angle control unit 13 are also supplied with power from the circuit power supply 24.

  Next, the coordinate detection unit will be described. In this embodiment, the coordinate detection unit is constituted by a stereo camera. The stereo camera 8 includes a left camera 6 and a right camera 7. Images captured by the left camera 6 and the right camera 7 are captured by the computer 23 via the image capturing unit 17. The captured image is processed by the image processing unit 18 to perform contour extraction described later. Thereafter, the coordinate calculation unit 19 calculates the three-dimensional coordinates of the extracted contour.

  Here, the current positions (angles) of the first angle control unit 12 and the second angle control unit 13 are always detected by the mirror position instruction / detection unit 15. The relative positional relationship calculation unit 20 compares the three-dimensional coordinates extracted by the coordinate calculation unit 19 with the angles detected by the mirror position instruction / detection unit 15, so that the laser projection unit 9 and the stereo camera 8 can be compared. The relative positional relationship, the positional relationship between the stereo camera 8 and the workpiece 26, and the positional relationship between the laser projection unit 9 and the workpiece 26 are obtained. The CAD data conversion unit 21 performs coordinate conversion on the information of the CAD data 22 based on the relative positional relationship between the laser projection unit 9 and the workpiece 26 calculated by the relative positional relationship calculation unit 20, and draws on the workpiece by the laser projection unit 9. Data to generate.

  Next, this embodiment will be described with reference to FIGS.

  FIG. 2 shows a workpiece 26 in which two cylindrical holes are machined in two places. The outlines of the cylindrical holes are workpiece outlines 24a and 24b.

  FIG. 3 shows the work 26 before the cylindrical hole is machined. A projection contour 25 is obtained by projecting design data onto the workpiece 26. As described above, one of the effects of this embodiment is that the final image of machining can be confirmed on the actual workpiece before machining by projecting the design data onto the actual workpiece before machining. is there.

  FIG. 4 shows a work 26 in which a cylindrical hole is machined halfway. One of the effects of the present embodiment is that by comparing the workpiece contour 24b and the projected contour 25, it is possible to visually confirm the processing remaining amount on the actual workpiece.

  FIG. 5 shows a state in which a cross line 27 is drawn on the punch mark 28 indicating the processing position. In an NC machine, a punch is punched by the NC machine itself before machining. As shown in FIG. 5, the machining punch position 28, that is, a cylindrical punching line 27 is projected on the center of a circle in the case of a cylindrical hole machining, thereby inputting the machining punch position, that is, the NC program. Whether or not the processed position matches the design support position can be confirmed in advance before processing, and it is possible to prevent erroneous cutting that causes processing at different positions.

  FIG. 6 shows a state in which cross-shaped lines 27a and 27b are drawn at the start point 28a and the end point 28b of the marking line, which is a reference for machining. By marking with the two intersections of the cross lines 27a and 27b as a guideline, it is possible to write the ruled line at the correct position with respect to the design support position. Alternatively, it is possible to confirm whether or not the ruled line has been marked at the correct position by checking whether or not the two intersections of the crossed lines 27a and 27b are on the marking line after marking. Become.

  FIG. 7 illustrates a specific procedure for detecting the remaining machining amount and the machining position deviation amount. First, an image is acquired with the left camera and the right camera with the laser drawing turned off (L1, R1). Then, the contour of the workpiece is extracted (L2, R2), stereo matching is performed after parallax correction (L3, R3) (LR1), and the three-dimensional coordinates of the workpiece contour are calculated (LR2). Next, an image is acquired with the left camera and the right camera while the laser drawing is OFF and the drawing is ON (L4, R4). Then, a difference image from the image acquired with the laser drawing turned off is generated (L5, R5), and after the parallax correction (L6, R6), stereo matching (LR3) is performed to calculate the three-dimensional coordinates of the laser drawing locus. (LR4). Finally, by comparing the calculated three-dimensional coordinates of the workpiece contour with the three-dimensional coordinates of the laser drawing trajectory (LR5), the remaining amount and the machining position deviation amount are obtained (LR6).

  The remaining amount may be defined, for example, as shown in FIG. The machining position deviation amount may be defined as shown in FIG.

  Here, in order to extract the arc outline of the cylindrical hole, for example, the processing shown in FIG. 10 may be performed. Specifically, first, the acquired image (A) is binarized (FIG. 10- (B)), and then connected components are calculated (FIG. 10- (C)). Specifically, the region selection is performed based on the shape feature amount (elliptical arc in the present embodiment). Next, the selected region is transformed into a minimum circumscribed circle (FIG. 10- (D)). Further, the region is expanded by the circular structural element (FIG. 10- (E)). In FIG. 10- (E), only two arcs are represented. Actually, however, in FIG. 10- (C), since the area is finely selected, it is actually the same as the selected area. There are a number of circular structural elements. Therefore, the sum area of all the areas is obtained (FIG. 10- (F)). Then, as shown in FIG. 10- (G), a region (analysis region) including a desired workpiece contour is narrowed down. Thereafter, the image is divided by threshold processing within the analysis region (FIG. 10- (H)), divided into line segments and elliptical arcs (including arcs) (FIG. 10- (I)), and the same circle is outlined. They are coupled (FIG. 10- (J)). Specifically, an ellipse is applied to the divided line segments and arcs, and processing is performed in which the center position and the radius within a certain range are regarded as the same circle. With the above processing, a desired workpiece contour can be extracted.

  In order for the operator to perform such processing, for example, as shown in FIG. 11, when an image is displayed on the monitor 29 and the operator presses the contour extraction button 107, the contour extraction processing described above is performed, and the extraction result May be displayed superimposed on the image. Here, when a plurality of desired workpiece contours (two in the example of FIG. 11) are extracted, the desired contour may be selected with the mouse pointer 102a as shown in FIG.

  Since the laser projection unit can also draw characters, as shown in FIGS. 13 and 14, the remaining amount and the deviation amount can be directly drawn on the work and visually taught to the operator. In this way, by visually indicating the remaining amount and deviation amount to the operator, not only can the design information be projected onto the workpiece using a laser beam, but also the comparison judgment between the design information and the machining result on the workpiece can be simplified. Can be done.

  Next, a method for obtaining the relative positional relationship between the stereo camera 8 and the laser projection unit 9 will be described with reference to FIG.

  First, a laser beam is projected to an appropriate position on the workpiece (FIG. 15- (a)). At this time, the angles of the first and second galvanometer mirrors are grasped by the mirror position instruction / detection unit 15 (FIG. 15- (b)). Then, the three-dimensional coordinates of the laser bright spot on the workpiece are measured with the stereo camera 8 (FIG. 15- (c)). This operation (Step 1) is repeated three times. You may carry out 4 times or more as needed. Then, as shown in FIG. 16, the relationship between the coordinates viewed from the stereo camera origin and the coordinates viewed from the laser projection unit 9 is obtained at three or more positions. Here, the origin of the stereo camera 8 is, for example, the lens center of the left camera 6. The origin of the laser projection unit is the mirror center of the first galvanometer mirror. Here, although the rotation centers of the first galvanometer mirror and the second galvanometer mirror are deviated, the two-angle designation projection method that takes into account the blur is formulated in Patent Document 2, and thus detailed description thereof is omitted. .

  Since the laser projection unit 9 designates only two angles, the first angle θn and the second angle φm, it is impossible to grasp at which distance the projected laser beam is irradiated onto the workpiece. That is, where the work surface is determined only by the information of point P1 (θ1, φ1) (r1 is undefined), point P2 (θ2, φ2) (r2 is undefined), and point P3 (θ3, φ3) (r3 is undefined). It is not possible to determine if there is. However, since the stereo camera 8 simultaneously grasps the three-dimensional coordinates of the points P1, P2, and P3 as P1 (x1, y1, z1), P2 (x2, y2, z2), and P3 (x3, y3, z3). Using these relationships, r1, r2, and r3 are uniquely determined. As a result, the relative positional relationship between the stereo camera 8 and the laser projection unit 9 is also obtained (FIG. 7- (f)).

Specifically, first, (θn, φn, rn) is converted into an orthogonal coordinate system.
P1: (θ1, φ1, r1) → (r1, cos θ1, cos φ1, r1, cos θ1, sin φ1, r1, sin φ1)
P2: (θ2, φ2, r2) → (r2, cos θ2, cos φ2, r2, cos θ2, sin φ2, r2, sin φ2)
P3: (θ3, φ3, r3) → (r3 ・ cosθ3 ・ cosφ3, r3 ・ cosθ3 ・ sinφ3, r1 ・ sinφ3)
Here, the unknowns are r1, r2, and r3.
On the other hand, the coordinates of the laser bright spot viewed from the stereo camera are as follows.
P1: (x1, y1, z1)
P2: (x2, y2, z2)
P3: (x3, y3, z3)
Here, since the distance between the points does not change in the coordinate system of the laser projector or the coordinate system of the stereo camera, the following equation holds.
| P1-P2 | = | p1-p2 |
| P2-P3 | = | p2-p3 |
| P3-P1 | = | p3-p1 |
As described above, there are three formulas for the unknown number 3, so that the unknowns are uniquely determined as r1, r2, and r3. Now, let the coordinates of the laser bright spot in the stereo camera coordinate system be (x1, y1, z1), (x2, y2, z2), (x3, y3, z3), and the laser bright spot coordinate in the laser projector coordinate system The coordinates are (X1, Y1, Z1), (X2, Y2, Z2), and (X3, Y3, Z3). Then, the outer centers of (x1, y1, z1), (x2, y2, z2), and (x3, y3, z3) are obtained and set as (x0, y0, z0). Next, the outer center of (X1, Y1, Z1), (X2, Y2, Z2), (X3, Y3, Z3) is obtained, and this is (X0, Y0, Z0). Here, let A be a vector from the origin of the stereo camera coordinate system to the outer center (x0, y0, z0). Also, let B be the vector from the origin of the laser projector coordinate system to the outer center (X0, Y0, Z0). From the viewpoint of different coordinate systems, (x0, y0, z0) and (X0, Y0, Z0) are the same point in the world coordinate system. Therefore, this point is set as the origin of the world coordinate system. Then, the vector from the origin of the world coordinate system to the origin of the stereo camera coordinate system is -A, and the vector from the origin of the world coordinate system to the origin of the laser projector coordinate system is -B. Therefore, the positional relationship between the stereo camera coordinate system and the laser projector coordinate system can be easily obtained from the vector-A and the vector-B. In addition, when two or more points are on the same straight line when the laser bright spot is viewed from the stereo camera and the laser projector, the mutual positional relationship cannot be obtained. Note that the laser bright spots should not be on the same line.

  Next, a specific procedure for obtaining the three-dimensional coordinates of the laser bright spot position on the workpiece with the stereo camera 8 will be described with reference to FIGS. First, for example, an image of the left camera 6 is displayed on the monitor 29. When the vicinity of the reference marker (laser starting point) 101 of the workpiece 26 is designated by the mouse pointer 102a, an enlarged window 103a is displayed. If the circle extraction button 105 is pressed in advance, the image processing unit 18 extracts a laser bright spot (round shape) in the enlarged display area (analysis area) and obtains the center of gravity of the circle. In order to confirm that the desired center of gravity has been obtained, for example, the position of the center of gravity of a circle may be displayed with a circle and a cross line 104a. Since this system has a stereo camera configuration, the coordinate calculation unit 19 calculates the three-dimensional coordinates of the position of the laser bright spot using a stereo matching technique. As the calculated three-dimensional coordinates, the calculated coordinate values may be displayed as in 108a. In addition, the first and second angle values may be displayed as in 109a.

  In FIG. 17, the analysis region is narrowed down by clicking the vicinity of the reference marker 101 with the mouse. However, as shown in FIG. 18, the analysis region may be narrowed down by drawing a square 110 with the mouse.

  Next, with respect to a specific procedure for obtaining the reference position on the work, for example, the three-dimensional coordinates of the feature points such as the reference marker and the corner, by the stereo camera 8, FIG. 17, FIG. 18, and FIG. It explains using. First, for example, an image of the left camera 6 is displayed on the monitor 29. This time, the circle 101 in FIGS. 17 and 18 is read as a reference marker. When the vicinity of the reference marker 101 is designated by the mouse pointer 102a, an enlarged window 103a is displayed. If the circle extraction button 105 is pressed in advance, the image processing unit 18 extracts the reference marker 101 (round shape) in the enlarged display area (analysis area) and obtains the center of gravity of the circle. In order to confirm that the desired center of gravity has been obtained, for example, the position of the center of gravity of a circle may be displayed with a circle and a cross line 104a. Since the present system has a stereo camera configuration, the coordinate calculation unit 19 calculates the three-dimensional coordinates of the reference marker using a stereo matching technique. As the calculated three-dimensional coordinates, the calculated coordinate values may be displayed as in 108a. In addition, the first and second angle values may be displayed as in 109a.

  As shown in FIG. 19, even if there is no reference marker 101, if there is a place where the coordinates of the workpiece itself are known, for example, the corner 114, the corner extraction button 106 is pressed in advance and the vicinity of the corner is selected with the mouse. By selecting, there is also a method of automatically recognizing the corner and calculating the three-dimensional coordinates of the corner.

  With the above processing, as shown in FIG. 20, the positional relationship between the work 26 and the stereo camera 8 is obtained. Thereafter, if the positional relationship between the stereo camera 8 and the laser projection unit 9 that has been grasped is used, the positional relationship between the workpiece 26 and the laser projection unit 9 can also be obtained uniquely.

According to the positional relationship between the workpiece 26 and the laser projection unit 9, the CAD data 22 is coordinate-converted by the CAD data conversion unit 21 to generate data for laser projection. Based on the laser projection data, the stage position instruction / detection unit 14 and the mirror position instruction / detection unit 15 are respectively converted into a linear motion stage control unit 11, a first angle control unit 12, and a second angle control unit 13. Drawing is performed by driving the linear motion stage 2, the first galvanometer mirror, and the second galvanometer mirror via.

The present invention relates to laser projection technology for performing prevention of erroneous cutting, machining status confirmation, and machining omission check in machining.

1 ... Laser source
2 ... linear motion stage,
3. Focusing lens,
4 ... 1st galvanometer mirror,
5 ... Second galvanometer mirror,
6 ... Left camera,
7 ... Right camera,
8 ... Stereo camera,
9 ... Laser projection unit,
10 ... Laser control unit,
11 ... Linear motion stage controller,
12, 13 ... Angle control unit,
14… Linear stage position indication / detection unit,
15 ... Mirror position indication / detection unit,
17 ... Image capture unit,
18: Image processing unit,
19 ... coordinate calculation unit,
20: Relative positional relationship calculation unit,
21 ... CAD data conversion unit,
22 ... CAD data,
23 ... computer,
24a… Work contour
25 ... projection contour,
26… Work,
27, 27a, 27b ... crossed lines
29… Monitor,
101 ... Reference marker,
105 ... circle extraction button,
106 ... Corner extraction button,
107… Outline extraction button

Claims (4)

A first step of controlling a plurality of mirror angles and irradiating a laser on a workpiece to be measured from a laser projection unit;
A second step of photographing the workpiece with a stereo camera, extracting a contour of the workpiece, and calculating three-dimensional coordinates;
A third step of determining the positional relationship between the laser projection unit and the workpiece by comparing the mirror angle with the three-dimensional coordinates of the workpiece contour calculated in the second step;
Based on the positional relationship between the laser projection unit and the workpiece obtained in the third step, comprising a fourth step of coordinate-converting CAD data information and rendering the CAD data from the laser projection unit to the workpiece. A laser projection method.   2. The laser projection method according to claim 1, further comprising a fifth step of comparing the three-dimensional coordinates of the CAD data with the three-dimensional coordinates of the actual contour of the workpiece and teaching the comparison result. Projection method.   3. The laser projection method according to claim 2, wherein the comparison result is taught on a display in the fifth step. A laser projection unit that irradiates a workpiece to be measured with a laser by controlling a plurality of mirror angles;
An image capturing unit that captures the workpiece by a stereo camera and captures a captured image; an image processing unit that extracts an outline of the workpiece from the image; and a coordinate calculation unit that calculates three-dimensional coordinates;
A relative positional relationship calculation unit that compares the calculated three-dimensional coordinates of the workpiece contour with the mirror angle to obtain a positional relationship between the laser projection unit and the workpiece;
A laser projection apparatus comprising: a CAD data conversion unit that coordinates-converts CAD data information based on a positional relationship between the laser projection unit and the workpiece obtained by the relative positional relationship calculation unit.