KR101684239B1

KR101684239B1 - Measuring system for a relative position between machining head and workpiece and a method for measuring the relative position using the same

Info

Publication number: KR101684239B1
Application number: KR1020150058134A
Authority: KR
Inventors: 김창주; 박천홍; 오정석
Original assignee: 한국기계연구원
Priority date: 2015-04-24
Filing date: 2015-04-24
Publication date: 2016-12-09
Also published as: KR20160126710A

Abstract

The relative position measurement system includes a stage portion, a machining head portion, and a measurement unit. A workpiece is placed on the stage portion. The machining head portion includes a machining head to which a tool for machining the workpiece is fixed. The measurement unit is connected to the machining head to measure the shape of the machining head and the workpiece in accordance with a change in position or attitude of the machining head.

Description

TECHNICAL FIELD [0001] The present invention relates to a relative position measuring system for measuring a relative position between a machining head and a workpiece, and a relative position measuring method using the same. BACKGROUND OF THE INVENTION [0002]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a relative position measuring system for a machining head and a workpiece and a relative position measuring method using the same, and more particularly, to a relative position measuring system for measuring a relative position between a machining head and a workpiece A relative position measuring system and a relative position measuring method using the relative position measuring system.

In the machining of the workpiece according to the prior art, it is common to perform machining based on the absolute position of the tool and the workpiece with reference to the fixed base coordinate system. To do this, it was necessary to measure the absolute position of the tool and the workpiece by performing a preliminary measurement of the coordinates of the tool and the workpiece before machining the actual workpiece.

In the case of performing the machining using the coordinate system for the absolute position as described above, since the coordinate system is fixed, there is an advantage that calculation for simple and continuous tool motion is easy. However, there is a problem in that errors are accumulated according to the position error of the feed system, the shape error of the guide, and the error of the assembly of the feed shaft. Accordingly, errors are greatly increased, there is a problem.

Accordingly, in the machining of a large workpiece, in particular, a technique of periodically measuring the coordinates of the tool and the workpiece during the machining process of the workpiece to reduce the machining error is applied, but the production cost and the production time are increased Ancillary problems have arisen.

Recently, with the development of image processing technology, a technique of reducing the time of absolute position measurement by measuring the position of a workpiece or a tool through a measuring device such as a camera is introduced before or during processing of the workpiece have.

For example, Korean Patent Registration No. 10-1450657 discloses a technique for controlling the position of a cutting wheel during processing of a cutting wheel through a laser unit on the basis of processing position information on a cutting wheel in a measuring unit, Discloses a technique of using a camera or a vision device as a measurement unit.

Japanese Patent Application No. 2009-22208 discloses a technique for picking up a position of a tool through a camera and determining a position of a tool edge through an image processing apparatus.

However, techniques for position imaging of a workpiece or a tool developed up to now are limited to measuring the absolute position of a tool and a workpiece based on a coordinate system of a fixed base, thereby reducing the time of coordinate measurement, There is a limitation that can not overcome the problem caused by the use of the absolute coordinate system described above.

SUMMARY OF THE INVENTION Accordingly, the present invention has been made in view of the above problems, and it is an object of the present invention to provide a machining apparatus and a machining method capable of performing machining more effectively by omitting a fixed structure of a machine tool, And a relative position measurement system of the machining head and the workpiece.

Another object of the present invention is to provide a relative position measuring method of a machining head and a workpiece using the relative position measuring system.

According to an embodiment of the present invention, there is provided a relative position measurement system including a stage unit, a machining head unit, and a measurement unit. A workpiece is placed on the stage portion. The machining head portion includes a machining head to which a tool for machining the workpiece is fixed. The measurement unit is connected to the machining head to measure the shape of the machining head and the workpiece in accordance with a change in position or attitude of the machining head.

In one embodiment, the machining head includes a mounting frame coupled to the machining head so as to be slid in a first direction, and an elongated frame having one end fixed to the machining head and the other end extended to fix the measuring unit .

In one embodiment, the machining head may further include a frame portion mounted on the stage portion and to which the machining head portion is detachably attached.

In one embodiment, the frame portion includes a first frame coupled to the machining head portion so as to be rotatable about the first direction, a second frame coupled to the first frame so as to slide in a second direction perpendicular to the first direction, And a third frame coupled to the second frame such that the second frame is slid in a third direction that is simultaneously perpendicular to the first and second directions.

In one embodiment, the measuring unit measures the shape of the workpiece at various positions or postures according to the position or posture of the machining head, and the shape of the measured workpiece is compared with the three- The relative position between the head and the workpiece can be calculated.

In one embodiment, the measurement unit may be a three-dimensional image sensor that recognizes a three-dimensional shape.

In one embodiment, the measurement unit measures the shape of the workpiece every time the position or attitude of the machining head changes, and the relative position of the machining head and the workpiece can be calculated.

In the relative position measuring method according to an embodiment of the present invention for realizing the object of the present invention, the position or attitude is changed according to the position or attitude of the machining head connected to the machining head, The shape of the workpiece located at the center of the workpiece is measured. Dimensional measurement data from the shape of the measured workpiece. The three-dimensional measurement data and the original data of the workpiece are matched. The relative position between the machining head and the workpiece is calculated.

In one embodiment, acquiring the three-dimensional measurement data comprises obtaining a color image in the shape of the measured workpiece, obtaining a depth image in the shape of the measured workpiece And acquiring a three-dimensional image by combining the color image and the depth image.

In one embodiment, the three-dimensional measurement data may be obtained via a three-dimensional image sensor.

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According to the embodiments of the present invention, the measuring unit is changed in accordance with the position or attitude change of the machining head, the shape of the workpiece can be measured, and the relative position between the machining head and the workpiece can be measured.

In this case, the measurement unit measures the shape of the workpiece at various positions or postures in accordance with the position or attitude change of the machining head, compares the shape of the measured workpiece with the original shape of the previously stored workpiece, The relative position can be calculated.

Further, the measurement unit can measure the shape of the workpiece every time the position or posture of the machining head changes, so that the relative position between the machining head and the workpiece can be calculated in real time during the machining, Can be improved.

Thus, by measuring the position between the machining head and the workpiece without a separate absolute coordinate system, it is possible to machine the desired shape of the workpiece, thereby omitting the base frame structure of the machine tool for setting the absolute coordinate system, It is unnecessary to produce a large-sized machine tool for machining a workpiece. As a result, a large workpiece can be machined only by a system for moving the machining head, and a machining system using a flexible robot can be realized, and the machining accuracy can be relatively improved.

1 is a perspective view showing a relative position measurement system of a machining head and a workpiece according to an embodiment of the present invention.
Fig. 2 is a perspective view showing a state in which the machining head is moved in the relative position measuring system of Fig. 1. Fig.
FIG. 3 is an image showing the shape of the workpiece recognized through the relative position measuring system of FIG. 1. FIG.
FIG. 4A is a schematic diagram showing a coordinate system in a state in which the machining head portion of the relative position measuring system of FIG. 1 is positioned at the first position. FIG.
Fig. 4B is a schematic diagram showing a coordinate system in a state where the machining head portion of the relative position measuring system of Fig. 1 is located at the second position. Fig.
5 is a flowchart showing a relative position measurement method of a machining head and a workpiece using the relative position measuring system of FIG.

While the present invention has been described in connection with what is presently considered to be the most practical and preferred embodiment, it is to be understood that the invention is not limited to the disclosed embodiments. It is to be understood, however, that the invention is not intended to be limited to the particular forms disclosed, but on the contrary, is intended to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the invention. Like reference numerals are used for like elements in describing each drawing. The terms first, second, etc. may be used to describe various components, but the components should not be limited by the terms.

The terms are used only for the purpose of distinguishing one component from another. The terminology used in this application is used only to describe a specific embodiment and is not intended to limit the invention. The singular expressions include plural expressions unless the context clearly dictates otherwise.

In the present application, the term "comprises" or "comprising ", etc. is intended to specify that there is a stated feature, figure, step, operation, component, But do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, parts, or combinations thereof.

Unless defined otherwise, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Terms such as those defined in commonly used dictionaries are to be interpreted as having a meaning consistent with the contextual meaning of the related art and are to be interpreted as either ideal or overly formal in the sense of the present application Do not.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 is a perspective view showing a relative position measurement system of a machining head and a workpiece according to an embodiment of the present invention.

1, the relative position measurement system 10 of a machining head and a workpiece according to the present embodiment includes a stage unit 100, a frame unit 200, a machining head unit 200, and a measurement unit 400 do.

The stage unit 100 corresponds to a stage for supporting the relative position measuring system 10 and includes an extension stage 110, a workpiece stage 120, and a rotation stage 130.

The extension stage 110 extends in a horizontal direction at the bottom and the workpiece stage 120 is connected to the extension stage 110 in a stage where the workpiece 500 is located. The rotary stage 130 is rotatably coupled on the workpiece stage 120 so that the workpiece 500 is rotated in the 'B' direction on the workpiece stage 120 ).

In the present embodiment, the stage unit 100 is described as having the shape as shown in FIG. 1, but the stage unit 100 is sufficient to support the relative position measuring system 10 , Can be modified into various forms, and is not limited to the structure shown in Fig.

1 is merely an example. It is sufficient that the frame part 200 is slidable so that the machining head can be mounted by the machining head part 300 described later. .

The frame unit 200 includes a first frame 210 extending in a first direction X, a second frame 220 extending in a second direction Y perpendicular to the first direction, And a third frame 230 extending in a third direction Z that is simultaneously perpendicular to the second directions.

The third frame 230 is coupled to the extension stage 110 of the stage unit 100 so as to be slidable along the third direction.

The second frame 220 extends a predetermined length in a vertical direction perpendicular to the third frame 230, that is, in a second direction, and the first frame 210 is extended horizontally That is, the first direction.

In this case, the pair of the second frames 220 may extend parallel to each other, and the first frame 210 may be coupled to the pair of second frames 220 at both ends thereof, 220 in the second direction (Y).

The machining head unit 200 is mounted on the frame unit 200 in a detachable manner and slides on the frame unit 200 to perform the machining of the workpiece 500.

Specifically, the machining head portion 200 includes a mounting frame 310, a machining head 320, a tool 330, and an elongate frame 340.

The mounting frame 310 is detachably mounted on the first frame 210. Specifically, the mounting frame 310 is fixed to both ends of the first frame 210 along the third direction while fixing both ends of the mounting frame 310 to the first frame 210, Respectively.

Accordingly, the mounting frame 310 can be rotated in the 'A' direction (that is, rotated in the first direction by the rotation axis) with respect to the first frame 210.

The machining head 320 is coupled onto the mounting frame 310 and slides along the first direction on the mounting frame 310.

A tool 330 is mounted on the machining head 320 in a direction in which the workpiece 500 is positioned. The tool 330 is used for milling tools, drills, and the like used in general- A laser beam to be applied to the workpiece, and an electrode used for electric discharge machining or the like.

However, in the present embodiment, the tool 330 is mounted on the machining head 320, and when the machining head 320 is moved, rotated, or changed in posture, And varies depending on the position or attitude of the processing head 320.

The elongate frame 340 is secured and extended to the mounting frame 310 in a direction opposite to the tool 330 mounted to the workpiece 500. In this case, the extension frame 340 may extend in the opposite direction to the tool 330, and may extend to the opposite side of the extension direction of the tool 330, as shown in FIG. 1, have.

The measuring unit 400 is fixed to the other end of the elongate frame 340 and the measuring unit 400 measures the working head 320 and the workpiece 500 as will be described later, The length of the elongated frame 340 can be designed in consideration of a measurement range of the work head 320 and a relative positional change of the work head 320 and the like.

That is, if the length of the elongated frame 340 is designed to be relatively short, the measuring area 401 measured by the measuring unit 400 is relatively wide, The measurement area 401 measured by the measurement unit 400 is relatively narrowed when the elongated frame 340 is designed to have a relatively long length, There may be an advantage that the degree of change of the measurement region 401 is reduced in accordance with the movement of the head 320.

Accordingly, the extension frame 340 is preferably designed in consideration of the measurement area 401 measured by the measurement unit 400.

The measuring unit 400 is fixed to the other end of the elongated frame 340 as described above, and measures the position of the processing head 320 and the workpiece 500. That is, the measurement area 401 is defined by the measurement unit 400 as shown in FIG. 1, and the position of the processing head 320 and the workpiece 500 located in the measurement area 401 is Respectively.

The tool 330 is mounted on the machining head 320 so that the relative position between the machining head 320 and the tool 330 is set to a preset value. 330 or the machining head 320 and the position of the workpiece 500 may be measured.

Further, when the relative position between the measuring unit 400 and the machining head 320 is also fixed, it is sufficient to measure the shape of the workpiece 500 in every changed position or posture of the machining head 320.

Alternatively, if the measuring unit 400 also has a relative position relative to the machining head 320, the measuring unit 400 may measure the shape of the machining head 320 and the workpiece 500 simultaneously .

1, the relative position measuring system has a structure in which the position and attitude are changed by three axes of XYZ and two axes of AB. However, the relative position measuring system may be arranged in various positions or positions And the measuring unit 400 may measure the workpiece 500 according to the position or attitude change so that the relative position between the workpiece 500 and the processing head 320 Can be calculated.

Fig. 2 is a perspective view showing a state in which the machining head is moved in the relative position measuring system of Fig. 1. Fig. FIG. 3 is an image showing the shape of the workpiece recognized through the relative position measuring system of FIG. 1. FIG.

2, when the machining head 300 rotates in the A direction and is fed a predetermined distance along the Y axis and the Z axis to machine the workpiece 500, the measurement unit 400 And the measurement state of the workpiece 500 via the measurement unit 400. [0051] As shown in FIG.

As such, during the machining of the workpiece 500, the measuring unit 400 may be positioned at various positions toward the workpiece 500, and at each changed position, the measuring unit 400 may measure the workpiece 500) can be measured.

In this case, the measurement unit 400 may be a three-dimensional image sensor that recognizes the three-dimensional shape of the workpiece 500, and thus, based on the data measured by the measurement unit 400, Can be derived.

However, since the measurement unit 400 measures the shape of the workpiece 500 during the machining process, the resulting three-dimensional shape may correspond to a part of the finished workpiece after the machining is completed .

For example, an image 600 of the workpiece 500 measured through the measurement unit 400 and derived in a three-dimensional shape may be as shown in FIG. 3, and the image 600 shown in FIG. 3 Are changed into various forms according to the position of the measurement unit 400 as described above.

FIG. 4A is a schematic diagram showing a coordinate system in a state in which the machining head portion of the relative position measuring system of FIG. 1 is positioned at the first position. FIG. FIG. 4B is a schematic diagram showing a coordinate system in a state where the machining head portion of the relative position measuring system of FIG. 1 is located at the second position. FIG.

4A and 4B, the workpiece coordinate system 510 corresponding to the absolute coordinates based on the workpiece 500 maintains a fixed state even when the position or posture of the machining head unit 300 changes.

On the other hand, as the position or posture of the machining head unit 300 changes, the position or attitude of the machining head 320 changes, and thus the position or attitude of the measurement unit 400 changes, The sensor coordinate system 410 measuring the workpiece 500 with reference to the workpiece 400 is changed.

Accordingly, the workpieces 500 fixed to the same position are measured in different positions or postures in the sensor coordinate system 410 based on the measurement unit 400, The coordinates of the measurement unit 400 can be derived from the shape of the workpiece 500 measured in another position or posture.

That is, the shape of the previously stored workpiece 500 and the shape of the workpiece 500 measured by the measurement unit 400 at an arbitrary position are compared with each other, and the shape of the measured workpiece is moved, The amount of movement of the measured workpiece, that is, the amount of movement of the workpiece on the three-dimensional plane can be calculated, and based on the calculated coordinate movement amount, The coordinates at which the measurement unit 400 is located can be calculated.

The position of the measurement unit 400 can be calculated by comparing the shape of the workpiece 500 measured by the measurement unit 400 and the shape of the predetermined workpiece, 400 and the machining head 320 or the tool 330 is defined as a predetermined value so that the relative position between the machining head 320 and the workpiece 500 can be measured do.

Therefore, since the relative position between the machining head 320 and the workpiece 500 can be measured as described above, information on the absolute position of the workpiece 500 during the machining process is unnecessary, It is possible to omit the base portion of the fixed type machining tool and the machining head connected thereto. Therefore, a machining head which is freely movable and spaced apart from the base portion can be constructed, and in particular, machining for a large workpiece is advantageous.

That is, it is possible to design various types of machining systems based on the machining head or relative positions of the tool and the workpiece.

5 is a flowchart showing a relative position measurement method of a machining head and a workpiece using the relative position measuring system of FIG.

5, in the method of measuring the relative position between the machining head and the workpiece using the relative position measuring system 10 according to the present embodiment, information about the three-dimensional shape of the workpiece 500 is stored in the database .

In this case, the information on the three-dimensional shape of the workpiece 500 may include information on the shape of the finished workpiece 500 in which the machined portion is reflected, as well as information on the shape of the finished workpiece 500 .

Therefore, when the shape of the workpiece measured at each step is difficult to match with the shape of the completed workpiece, it is possible to calculate a more accurate relative position by matching with the shape of the workpiece reflected only at the part processed at the step.

On the other hand, as the machining is performed, the measuring unit 400 measures the shape of the workpiece 500 (step S10).

In this manner, the three-dimensional measurement data is acquired from the shape of the workpiece 500 measured by the measurement unit 400 (step S20).

Specifically, the step of acquiring the three-dimensional measurement data of the workpiece 500 includes the steps of acquiring a color image from the information about the shape of the measured workpiece 500 (step S21) Acquiring a depth image from the information on the shape of the workpiece 500 (step S22), and acquiring a three-dimensional image by combining the color image and the depth image (step S23) .

In this case, the measurement unit 400 is a three-dimensional image sensor, and the three-dimensional measurement data corresponds to image information obtained through a three-dimensional image sensor.

Thus, a three-dimensional image of the measured workpiece 500 is acquired, and the image 600 of the measured workpiece 500 is implemented based on the three-dimensional image, and the original data of the previously stored workpiece 500 is matched with each other Step S30).

In this case, the three-dimensional image of the measured workpiece 500 is matched (700) to the original data of the workpiece 500 through the movement of the coordinate system. In the matching process, information about the movement amount of the coordinate system do.

That is, the information about the movement amount of the coordinate system is the information about the position of the measurement unit 400, and the relative position between the machining head 320 and the workpiece 500 is calculated based on this information (step S40 ).

More specifically, the original data of the workpiece 500 is compared with the three-dimensional image of the workpiece 500 measured by the measurement unit 400 at an arbitrary position, and the image of the measured workpiece is moved Rotation, enlargement, or reduction of the workpiece and superimposes it on the original data of the workpiece, it is possible to calculate the amount of movement of the measured workpiece, that is, the amount of coordinate movement on the three-dimensional surface, The coordinates where the measurement unit 400 is located are calculated.

Thus, when the coordinates of the measurement unit 400 are calculated, the relative positions of the machining head 320 and the workpiece 500 are calculated.

As described above, the relative positions of the machining head 320 and the workpiece 500 are calculated from the three-dimensional measurement data of the workpiece 500 measured by the measurement unit 400 mounted on the machining head 320 The position information on the workpiece can be obtained in a state where the workpiece 320 is located at various positions other than the base or the stage on which the machining head 320 is fixed, so that the machining can be performed on the workpiece, Can be performed using a relatively simple machining system.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the present invention as defined by the following claims. It can be understood that it is possible.

The relative position measuring system of the machining head and the workpiece and the relative position measuring method using the same according to the present invention can be used for processing various types of workpieces such as laser processing, high speed processing and large workpiece processing as well as general purpose machine tools Lt; / RTI >

10: Relative position measuring system
100: stage unit 200: frame unit
210: first frame 220: second frame
230: third frame 300: processing head
310: mounting frame 320: machining head
330: tool 340: extended frame
400: measurement unit 401: measurement area
410: sensor coordinate system 500: workpiece
510: Workpiece coordinate system

Claims

A stage portion on which the workpiece is placed;
A machining head including a machining head to which a tool for machining the workpiece is fixed at an end; And
And a measuring unit connected to the machining head for measuring a shape of the machining head and the workpiece in accordance with a change in position or attitude of the machining head,
The measuring unit measures the shape of the workpiece at various positions or postures in accordance with the position or posture of the machining head to calculate a relative position between the machining head and the workpiece,
The relative position between the machining head and the workpiece is determined by calculating the coordinate shift amount of the measured workpiece when the shape of the measured workpiece is moved, rotated, enlarged or reduced so as to overlap with the original data of the workpiece Relative position measurement system.

The image forming apparatus according to claim 1,
A mounting frame coupled to the machining head so as to slide in a first direction; And
Further comprising an elongated frame extending from one end to the other end to fix the measuring unit and the machining head to the other end.

3. The method of claim 2,
And a frame portion mounted on the stage portion and adapted to be detachably attached to the machining head portion.

The apparatus according to claim 3,
A first frame coupled to the machining head portion so as to be rotatable about the first direction;
A second frame coupled to the first frame such that the first frame is slid in a second direction perpendicular to the first direction; And
And a third frame coupled to the second frame such that the second frame is slid in a third direction that is simultaneously perpendicular to the first and second directions.

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The method according to claim 1,
Wherein the measurement unit is a three-dimensional image sensor for recognizing a three-dimensional shape.

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Measuring a shape of a workpiece placed on the stage portion, the position or posture being changed according to a position or an attitude change of the machining head, the machining head being connected to a machining head having a tool fixed at an end thereof;
Obtaining three-dimensional measurement data from the shape of the measured workpiece;
Matching the three-dimensional measurement data with original data of the workpiece; And
Calculating a relative position between the machining head and the workpiece,
The relative position between the machining head and the workpiece is determined by calculating the coordinate shift amount of the measured workpiece when the shape of the measured workpiece is moved, rotated, enlarged or reduced so as to overlap with the original data of the workpiece Of the relative position.

9. The method of claim 8, wherein obtaining the three-
Obtaining a color image in the shape of the measured workpiece;
Obtaining a depth image in the shape of the measured workpiece; And
And combining the color image and the depth image to obtain a three-dimensional image.

10. The method of claim 9,
Wherein the three-dimensional measurement data is obtained through a three-dimensional image sensor.

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