JP6486632B2 - Tool shape acquisition method and apparatus - Google Patents

Description

  The present invention relates to a method for acquiring the shape (including dimensions) of a tool from a camera image of the tool, and particularly to a method for acquiring the shape of a tool mounted on a tool post of a machine tool. .

  In a machine tool that processes multiple workpieces by attaching multiple tools to the tool magazine or turret tool post, the tool data of each tool installed at the tool mounting position of the tool magazine or turret tool post is registered in the controller in advance. It is necessary to keep. There are rotating tools such as drills and milling tools and fixed tools such as cutting tools. There are also different types of cutting tools for inner diameter and outer diameter, and there are many types with different cutting edge directions and shapes. .

  The positional relationship between the position of the tool edge when mounted on the tool post and the reference position of the tool post (the position controlled by the controller) differs for each tool. Accordingly, the workpiece cannot be machined into a desired shape unless the positional relationship (tool offset value) is registered in the controller. In addition, when the tool post moves, the shape of the tool attached to the tool post is registered in the controller in order to prevent the tool attached to the tool post from colliding with the workpiece being processed or the machine body. It is necessary to keep it.

  If the type and dimensions of the tool are known, the substitute tool shape can be determined. In other words, if the shape of the tool is known, it is possible to determine the type of tool and detect the size.

  The tool is mounted on the tool magazine and the turret by the operator during the setup work, which is preparation work. When the operator mounts a tool, the operator inputs tool data (such as the type and size of the tool) of the tool mounted from the operation panel in association with the tool mounting position. However, registration of tool data to the controller by manual input by the operator has a problem that it is troublesome and takes time, and input errors are likely to occur.

  Therefore, a method has been proposed in which the tool mounted on the tool post is photographed with a camera and the image is analyzed to detect the shape and approximate dimensions of the tool, and a part of the tool data is automatically input. . Also, when an IC chip is attached to the tool holder used when the tool is mounted on the turret, the tool data of the tool mounted on the holder is registered in the IC chip, and when the tool is mounted on the tool post, A method of registering tool data by reading the registration data of the IC chip into a controller has been proposed.

JP 2000-24880 A

  A method of acquiring tool data from an image obtained by photographing a tool with a camera due to improvement in resolution of the camera and improvement in image analysis technology is becoming an effective means. In this case, in order to register the tool data of the tool that is currently mounted at the tool mounting position of the tool magazine or turret tool post to the controller, the image was taken with the tool mounted on the tool magazine or turret tool post. A process of recognizing the tool shape from the image is necessary.

  However, in the image taken with the tool mounted on the machine tool, various members of the machine tool are reflected in the background, and these members have the same metallic luster as the tool. It is extremely difficult to extract the image.

  Therefore, in order to avoid this difficulty, when photographing a tool with a camera, a flat plate that hides the background is inserted at a position that becomes the background, or a cloth that covers a member that is reflected as a background is inserted and photographed. According to this method, it is possible to obtain an image in which the contrast between the tool or the tool rest and the background thereof is greatly different, so that the accurate shape of the tool can be detected by relatively simple image analysis.

  However, in this method, it is necessary to install a background plate or cloth (background plate or background cloth) as a background when photographing, and the work area where the tool post is placed is surrounded by a partition and a door. In recent machine tools, it is very troublesome to attach the background plate and the background cloth, and there is a risk of damaging the operator's arm with a tool attached to the tool post.

  On the other hand, in the method of registering tool data in the IC chip of the tool holder, the data must be registered manually when registering the tool data in the IC chip. This causes the same problem as when registering with the controller. In addition, since the IC chip is mounted not on the tool itself but on the tool holder, when the tool mounted on the holder is changed, it is also necessary to newly register the tool data.

  The present invention solves such problems of the prior art, and it is difficult to attach a tool magazine or a turret tool post, particularly a background plate or background cloth, without using a background plate or background cloth, and is close to a tool. It is an object of the present invention to provide means for detecting a tool shape by simple image analysis from an image obtained by photographing a tool mounted on a tool post having a member having a metallic luster similar to that of a tool at a position.

  In the present invention, the camera 2 is installed in a machine tool, and the tool post 1 is mounted in the imaging region of the camera 2 with the tool 3 (3a, 3b, 3c) attached to the tool post 1 (1a, 1b, 1c). By moving in and out, a digital image A that shows the tool 3 and a digital image B that does not appear are photographed, and by taking the difference between the two digital images, the image E of only the tool post and the tool with the background removed. Is obtained, and the shape of the tool 3 is acquired in a state of being mounted on the tool post 1 by image analysis of the image E, thereby solving the above-described problem.

  That is, according to the tool shape acquisition method of the present invention, the camera 2 for photographing the tool 3 mounted on the tool post 1 positioned at a predetermined position in the machining area of the machine tool is installed, and the tool 3 is mounted on the tool post 1. A digital image A obtained by moving the tool rest 1 to a position where the tool 3 is within the photographing area of the camera 2 and a digital image obtained by moving the tool rest 1 to a position where the tool 3 is outside the photographing area. The difference image C obtained by subtracting the luminance of the other B from the luminance of one A of the two digital images A and B, and the difference image D of the difference image D obtained by subtracting the luminance of the first A from the luminance of the other B By combining C and D to create a composite image E with the background removed, and extracting the shape of the tool 3 from the composite image E, the tool shape can be clearly recognized without using a background plate or background cloth. The tool image that can be obtained It is.

  In the present invention, a complicated member having a metallic luster similar to that of the tool 3 is reflected as a background in the digital image A obtained by photographing the tool 3 in the machine, and a lathe blade that requires a lot of work to insert a background plate or a background cloth This is particularly effective for acquiring the shape of the tool 3 mounted on the table 1. In this case, since the front of the tools 3a and 3b can be directed to the camera 2 by rotation around the indexing axes a and b of the turret tool post 1a and 1b, the degree of freedom with respect to the installation position of the camera 2 in the machine is large. Moreover, it is possible to photograph the tool 3 mounted on the plurality of tool rests 1 with one camera 2.

  The tool shape acquisition apparatus according to the present invention includes a camera 2 installed so that a part of the moving region of the tool post 1 is an imaging region, and a controller 5 that controls the moving operation of the tool post 1 and the imaging operation of the camera 2. The controller 5 includes tool shape acquisition means 50. The tool shape acquisition means 50 includes an image acquisition means 52 for acquiring digital images A and B when the tool post 1 is positioned in the imaging area of the camera 2 and moved outside the imaging area, and the digital image A and B The background removal means 53 for creating the difference image C, D from one A to the other B and the other B to the one A and synthesizing the difference images C, D, and the image of the tool 3 from the synthesized image E And image analysis means 54 for extracting.

  According to this invention, when automatically acquiring the shape of the tool mounted at each tool mounting position of the machine tool, there is no possibility of erroneously recognizing the tool shape, and the background when shooting the tool in the machine tool. It eliminates the need to install materials such as boards and background cloth, eliminates the need to attach the background board and background cloth, and eliminates the need to input tool data to the IC chip, reducing the burden on the operator. Is done.

  And by registering the shape and tool data of the tool that may be used in the machine tool in advance in the controller, the tool type is automatically determined from the acquired tool shape and registered as tool data from the image. By detecting the dimensions, there is an effect that tool data can be automatically input.

Side view of a schematic device showing an embodiment in a lathe Explanatory drawing showing the background removal procedure Side view of a schematic device showing an embodiment of a compound lathe

  Preferred embodiments of the present invention will be described below with reference to the drawings. FIGS. 1 and 2 are views showing a first embodiment of the present invention and showing an embodiment in a slant type lathe provided with turret tool rests 1a and 1b above and below a spindle axis c. The turret tool post 1a, 1b is rotatable about indexing axes a, b parallel to the main axis c, and is parallel to the inclined bed upper surface S in the X-axis direction and main axis c. It is movable in the direction perpendicular to the plane of the drawing (Z-axis direction). The rotation angle and movement position of the turret tool post 1a, 1b are accurately controlled by a lathe controller 5.

  The camera 2 arrange | positions the tool 3a, 3b which is going to image | photograph in the position which image | photographs from the front of the front direction, ie, the advancing direction of the blade edge with respect to a workpiece | work. In a lathe in which the tool post 1 is arranged above and below the spindle axis c, by changing the direction of the camera 2, both the tools 3a and 3b mounted on the upper and lower tool supports 1a and 1b can be photographed from the front. A camera 2 can be arranged.

  In the example shown in the figure, assuming that the main shaft 4 rotates in the direction of arrow R, the tool 3a of the lower turret tool post 1a rotates around the index axis a by an angle θ from the position facing the main shaft axis c (the position for machining the workpiece). An angle about the index axis b from the direction in which the tool 3a is photographed from the front (hereinafter referred to as “θ perpendicular direction”) d and the position where the tool 3b of the upper turret tool post 1b faces the main axis c. The camera 2 is rotated about an axis f parallel to the main axis c, at a position where the direction of photographing the tool 3b when it is rotated by φ (hereinafter referred to as “φ perpendicular direction”) e intersects. It is installed so that it can be positioned.

  The θ perpendicular direction d and the φ perpendicular direction e are the same for all tools mounted on the turret tool post 1a, 1b, and the distances La, Lb from the camera 2 to the tools 3a, 3b in the respective directions are also respectively provided. Since the directions d and e and the distances La and Lb are registered in the controller 5 or calculated, the tools 3a and 3b to be photographed are photographed at an accurate position on the camera image with an accurate focus. be able to.

  It should be noted that the position of the upper and lower tool rests in the X-axis direction during tool photographing is preferably the position when the tools 3a and 3b are mounted on the tool rests 1a and 1b. Since it can move to a precise position, the installation position of the camera 2 has a certain degree of freedom. Accordingly, the camera 2 is not obstructed by loading / unloading of the workpiece or being obstructed by scattering of cutting fluid or chips during machining in consideration that the tool post 1a, 1b can move in the X-axis direction. It is possible to install at a position.

  Next, the shape acquisition operation of the tool 3a mounted on the lower tool rest 1a in the above lathe will be described. After the turret tool post 1a is rotated so that the predetermined tool mounting position of the tool 3a faces the operator side and the tool 3a is mounted, the tool shape acquisition means (program) 50 registered in the controller 5 is executed.

  The imaging preparation means 51 of the tool shape acquisition means 50 determines the index angle θ at the time of imaging the tool of the lower turret tool post 1a registered in the controller 5, the distance La from the camera 2 to the tool 3a, and the position in the X-axis direction. Referring to the lower turret tool post 1a so that the newly mounted tool comes to the index position θ, the lower turret tool post 1a is moved to the registered position in the X-axis direction, and the camera 2 is moved. The camera 2 is focused in the direction perpendicular to θ.

  Next, the image acquisition means 52 of the tool shape acquisition means 50 causes the tool 3a to move to the camera 2 by the digital image A in a state where the tool 3a is in the imaging region of the camera 2 and the movement of the tool post 1a in the Z-axis direction. And the digital image B at the same location after moving to a position outside the imaging region. Only the background is shown in the digital image B.

  The background removal unit 53 of the tool shape acquisition unit 50 includes a difference image C (C = A−B) obtained by subtracting the luminance of the image B from the image A for the luminance of each pixel of the two digital images A and B, and the image A difference image D (D = B−A) is created by subtracting the luminance of the image A from B, and then a composite image E (E = C + D) is created with the sum of the luminances of both difference images as the luminance.

  Since the luminance of the difference image does not become negative, the luminance 0 is placed in the portion where the luminance of the pixels of the respective difference images C and D is negative, and the difference image becomes black. Since the background other than the part in which the tool 3a and the tool post 1a are reflected should have the same brightness in the digital images A and B, the background part becomes 0 in both the difference image C and the difference image D. Yes. Then, by combining the two difference images C and D, a composite image E in which the tool 3a and the lower turret tool post 1a are reflected in a black background is obtained.

  Since the shape of the tool post 1a is known, the image analysis means 54 of the tool shape acquisition means 50 detects the shape of the tool 3a by image analysis of the composite image E. Although not specifically described in the above description, noise removal such as spike noise removal may be performed as necessary during the image processing.

  Moreover, the brightness | luminance of the background in the images A and B may change with the lighting conditions and the shadow and reflection of a tool post. In this case, an image showing the tool post in a state where no tool is mounted (an image corresponding to the image A) and an image not showing the image (an image corresponding to the image B) are acquired in advance to obtain a difference in luminance of the background. It may be detected and registered in the controller, and the luminance of the background may be corrected with the luminance difference registered when the difference image is acquired.

  The above is the procedure for acquiring the shape of the tool 3a attached to the lower turret tool post 1a. When acquiring the shape of the tool 3b attached to the upper turret tool post 1b, the tool 3b is attached to the upper turret tool post 1b. After that, the only difference is that the upper turret tool post 1b is rotated by φ, the optical axis of the camera 2 is turned in the direction perpendicular to φ, and the distance to the tool is set to Lb. The shape of the tool 3b attached to the upper turret tool post 1b is acquired by the procedure.

  FIG. 3 is a view showing a second embodiment of the present invention. The present invention is applied to a slant-type compound lathe in which a composite tool post 1c having a rotary tool shaft and a turret tool post 1a are arranged above and below a main spindle axis c. It is the figure which showed the example which implemented. The composite tool post 1c of this type of composite lathe can move in the Y-axis direction orthogonal to the Z-axis and the X-axis, and can turn around the Y-axis. In addition, there is a tool magazine containing a large number of tools to be mounted on the composite tool post 1c, and an automatic tool changer (not shown) for exchanging tools between the tool magazine and the composite tool post 1c. Is provided.

  The mounting position of the camera 2 in the second embodiment is a position at which the θ perpendicular direction for photographing the tool 3a of the turret tool post 1a intersects with the Y-axis direction for photographing the tool 3c of the upper tool post 1c. The camera 2 is mounted so as to be rotatable and positionable in the direction perpendicular to θ and in the Y-axis direction about an axis f parallel to the main axis c.

  The procedure for acquiring the shape of the tool 3a mounted on the lower tool post is the same as that in the first embodiment, and therefore the description thereof will be omitted. The procedure for acquiring the shape of the tool mounted on the tool magazine will be described below.

  The operator sequentially attaches necessary tools to the tool magazine and executes the tool shape acquisition means 50. The imaging preparation means 51 of the tool shape acquisition means causes the operator to input the tool mounting position on which the tool for acquiring the shape is mounted, moves the tool mounting position to the tool replacement position, and moves the tool mounting position to the composite tool post 1c with the tool replacement device. After the mounting, the composite tool post 1c is moved to the photographing region of the camera 2 by moving the composite tool post 1c in the X and Z axis directions, the camera 2 is directed in the Y axis direction, and the tool 3c from the registered camera 2 is moved. The camera 2 is focused with reference to the distance Lc.

  Hereinafter, the tool shape is acquired by the same procedure as that for acquiring the tool shape of the lower turret tool post of the first embodiment by the image acquisition unit 52, the background removal unit 53, and the image analysis unit 54, The tool data obtained by the calculation is used as the shape of the tool mounted at the tool mounting position moved to the tool replacement position.

  By comparing the tool shape acquired as described above with the shape data for each tool type registered in the controller in advance by the tool discriminating means registered in the controller, the tool type is determined, and the tool of that type The temporary tool offset value can be measured from the image with reference to the direction and shape of the blade edge registered for. The temporary tool offset value can be used to automatically set the movement destination of the tool post when the tool edge of the tool is detected by a tool setter (a device for detecting the edge of the tool installed in the machine tool). In addition, by using a high-resolution camera, it is possible to process a workpiece using the tool offset value acquired from the tool dimension measured on the image as it is as the tool offset value.

1 (1a, 1b, 1c) Tool post 2 Camera 3 (3a, 3b, 3c) Tool 5 Controller 50 Tool shape acquisition means 52 Image acquisition means 53 Background removal means 54 Image analysis means A Digital image B Digital image C Difference image D Difference image E Composite image a, b Index axis

Claims (4)

A camera for photographing a tool mounted on a tool post moved to a predetermined position in the machining area of the machine tool is installed, the tool is mounted on the tool post, and the tool is mounted at a position where the mounted tool enters the camera capturing area. Acquire a digital image captured by moving the platform and a digital image captured by moving the tool rest to a position where the tool is outside the imaging area, and subtracting the other brightness from the brightness of one of the two digital images. A tool shape acquisition method of combining the difference image of the difference image and the difference image obtained by subtracting one luminance from the other luminance to remove the background and extracting the shape of the tool from the synthesized image.   The shape of the tool according to claim 1, wherein the tool is mounted on a turret tool post, and the digital image is acquired after the front of the tool is directed to the camera by rotation around the index axis of the turret tool post. Acquisition method.   In a lathe equipped with a tool post above and below the spindle axis, the camera is installed so that it can be rotated and positioned in at least two directions around an axis parallel to the spindle axis. The tool shape acquisition method according to claim 2, wherein a digital image of the tool mounted on the tool post is acquired. A camera installed so that a part of the moving region of the tool post becomes a photographing region, and a controller that controls the moving operation of the tool post and the photographing operation of the camera;
The controller includes an image acquisition unit that acquires a digital image when the tool post is positioned in the imaging region of the camera and moves outside the imaging region, and one luminance of the digital image acquired by the image acquisition unit. and background removal means for creating a composite image by combining the difference image obtained by subtracting one of the luminance from the difference image by subtracting the other luminance and the other luminance from the image analysis means for extracting an image of the tool from the composite image A tool shape acquisition device for a machine tool, comprising tool shape acquisition means including

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