KR20130086356A - Tool collision prevention system and tool collision prevention method - Google Patents

Abstract

Three-dimensional measurement of the work piece including the work piece 3 processed by the tool 2 of the machine tool 1 is performed in advance, and based on the measurement result, the tool 2 and the work piece collide with each other. A tool collision avoidance system for determining whether or not a collision is to be determined, comprising: a laser scanner 5 that three-dimensionally measures the shape of a workpiece, and a workpiece that determines the shape of the workpiece based on a measurement result of the laser scanner 5 In the case where the shape determining portion 33 is provided and the workpiece shape determining portion 33 includes an unmeasured area in which the shape of the workpiece is not measured in the measurement result of the laser scanner 5, The shape interpolation part 35 which interpolates the shape of a to-be-worked part so that the shape of a to-be-worked part may be determined with respect to an unmeasurement area | region or the outer side of the external part is included.

Description

TOOL COLLISION PREVENTION SYSTEM AND TOOL COLLISION PREVENTION METHOD}

BACKGROUND OF THE INVENTION Field of the Invention The present invention relates to a tool collision avoidance system for preventing a collision of a tool to a workpiece in a machine tool.

In a machine tool, in order to avoid a tool colliding with a workpiece, laser beam is irradiated, three-dimensional measurement of the shape of the workpiece is performed, and simulation of a process of processing the workpiece is performed (for example, refer to Patent Document 1). ). On the other hand, as a device for three-dimensional measurement of the shape of the workpiece, the workpiece is placed on a swivel and rotated to measure the square area to remove the blind spot (see Patent Document 2), or to mirror the optical path of the three-dimensional sensor for irradiating line light. It is known to reduce the blind area by changing to mirror (see Patent Document 3).

Japanese Patent Publication No. 2007-48210 Japanese Patent Publication No. 2003-75139 Japanese Patent Publication No. 2008-203091

In the three-dimensional measurement of the shape of a workpiece in a machine tool, an unmeasured area including a blind area that cannot measure the shape of the workpiece may be generated depending on the equipment of the machine tool, and an accurate shape may not be grasped. . The retrofitting of the apparatuses of Patent Literatures 2 and 3 is not advantageous in terms of cost, and it is desired to avoid the collision of the tool to the workpiece even when using data having an unmeasured area.

Accordingly, an object of the present invention is to provide a tool collision preventing system and a tool collision preventing method which can reliably prevent a tool from colliding with a workpiece even when there is an unmeasured area in the case of three-dimensional measurement of the shape of the workpiece. do.

The tool collision avoidance system of the present invention three-dimensionally measures a workpiece including a workpiece to be processed by a tool of a machine tool, and determines whether the tool and the workpiece are colliding based on the measurement result. A tool collision avoidance system for performing a collision determination, comprising: measuring means for three-dimensionally measuring the shape of the workpiece, and shape determining means for determining the shape of the workpiece based on a measurement result of the measurement means, When the shape determining means includes an unmeasured area in which the shape of the workpiece is not measured in the measurement result of the measurement means, the shape determining means is more than the outer shape or the outline of the workpiece in relation to the unmeasured area. Shape interpolation means for interpolating the shape of the workpiece to determine the shape of the workpiece on the outside is included By solving the above problems.

According to the tool collision avoidance system of the present invention, when the unmeasured area is included in the measurement result of the workpiece measured by the measuring means, the shape of the workpiece is interpolated as an actual shape or larger than that. do. As a result, the shape of the workpiece is larger than the actual appearance, but it is possible to reliably avoid collision of the tool. Even when a warning is given that the tool collides in the interpolated shape, only a step for the operator to confirm is added, and the collision of the tool is surely avoided. Simple and easy configuration avoids tool collisions without the need for additional equipment. In addition, the workpiece part is a concept including the case of only the workpiece | work and the case including other structures, such as a jig, a table, a measuring instrument, etc. which support a workpiece | work in addition to a workpiece | work. In addition, "outer than the external shape of the workpiece" includes a shape that protrudes toward the inner circumferential side of the recess when the recess is provided in the workpiece, and has a volume larger than that of the original workpiece. The concept of determining the shape by stretching is included.

In one aspect of the tool collision avoidance system of the present invention, the shape interpolation means includes missing coordinate data indicating a portion of the three-dimensional coordinate data acquired by the measurement means and indicating the unmeasured area. If so, the interpolation coordinate data is determined based on the adjacent coordinate data without missing data, and the interpolated coordinate data is interpolated to the missing coordinate data to form the shape of the workpiece. You may interpolate. According to this aspect, interpolation coordinate data is determined with respect to missing coordinate data based on the adjacent coordinate data adjacent to this. As a result, the missing coordinate data is interpolated, and the collision of the tool can be reliably avoided by interpolating the shape of the workpiece.

In the case of determining interpolation coordinate data based on adjacent coordinate data, the shape interpolation means compares adjacent coordinate data groups adjacent to the missing coordinate data and selects adjacent coordinate data having a maximum value among the adjacent coordinate data groups. You may determine as interpolation coordinate data. According to this aspect, the maximum value is interpolated as interpolation coordinate data among the several adjacent coordinate data group adjacent to the missing coordinate data. As a result, the collision of the tool can be reliably prevented by making the shape to be interpolated to the maximum size that can be considered while preventing the unmeasured area having an unclear shape from becoming smaller than the actual appearance.

In the tool collision prevention method of the present invention, the workpiece part including the workpiece to be processed by the tool of the machine tool is three-dimensionally measured in advance, and based on the measurement result, whether the tool and the workpiece part collide with each other. A tool collision prevention method for determining a collision of a tool, comprising: a measurement step of three-dimensionally measuring the shape of the workpiece, and a shape determination step of determining the shape of the workpiece based on a measurement result of the measurement step, In the shape determining step, when the measurement result of the measurement step includes an unmeasured area in which the shape of the workpiece is not measured, the shape determination step is performed more than the external shape or the external shape of the workpiece part with respect to the unmeasured area. Includes a shape interpolation step of interpolating the shape of the workpiece to determine the shape of the workpiece on the outside This problem is solved. The tool collision avoidance method of the present invention is implemented as a tool collision avoidance system of the present invention.

As described above, in the tool collision preventing system and the tool collision preventing method of the present invention, when the unmeasured area is included in the measurement result of the workpiece part measured by the measuring means, the actual shape or a shape larger than that. By interpolating the shape of the workpiece. As a result, the shape of the workpiece is larger than the actual appearance, but it is possible to reliably avoid collision of the tool.

1 is a schematic diagram of a machine tool and a tool collision avoidance apparatus to which a tool collision avoidance system according to one aspect of the present invention is applied.
2 is a functional block diagram of a machine tool and a tool collision avoidance device.
3 is a diagram illustrating a relationship between a laser scanner and a workpiece.
4 is a diagram illustrating a rectangular area.
5 is a flowchart for explaining shape interpolation processing.
FIG. 6A is a diagram illustrating shape interpolation between rectangular and discontinuous regions, and FIG. 6B is a diagram illustrating shape interpolation performed on the workpiece of FIG. 6A.
7 is a diagram illustrating an example of missing coordinate data.

1, the schematic diagram of the machine tool and tool collision prevention apparatus to which the tool collision prevention system which concerns on one form of this invention was applied is shown. The machine tool 1 is a machine that operates sequentially according to an NC program. The machine tool 1 includes a tool 2, a workpiece 3 as a workpiece part processed by the tool, a tool measurement sensor 4 for measuring the length and diameter of the tool 2, The laser scanner 5 as a measuring means which measures the shape of the workpiece | work 3 three-dimensionally, and the monitor 6 by which various messages are displayed as needed are provided. On the other hand, the tool collision avoidance apparatus 10 is comprised as what is called a personal computer. The connection line which connects the tool collision avoidance apparatus 10 and the machine tool 1 is a USB line 7 for transmitting / receiving the measured value of the shape of the workpiece | work 3 measured by the laser scanner 5, and An Ethernet (registered trademark) line 8 for transmitting and receiving other information is provided. In addition, the tool measurement sensor 4 and the laser scanner 5 may use various well-known techniques. Various scanners capable of three-dimensional measurement can be applied to the laser scanner 5.

The functional block diagram of the machine tool 1 and the tool collision avoidance apparatus 10 is shown in FIG. The machine tool 1 is provided with the control part 21. The control unit 21 is configured as a unit which combines a microprocessor and various peripheral devices such as internal storage devices (for example, ROM and RAM) required for the operation of the microprocessor. The control unit 21 performs control necessary for the operation of the machine tool 1. The tool collision avoidance apparatus 10 is equipped with the control part 31 and the connection interface 32. As shown in FIG. The control part 31 is comprised as a unit which combined the microprocessor and various peripheral devices, such as internal memory (for example, ROM and RAM) required for the operation of the microprocessor, and comprises a user interface, such as a monitor and a keyboard which are not shown in figure. Have. The control part 31 is provided with the workpiece shape determination part 33 and the collision determination part 34 as shape determination means. The workpiece shape determining unit 33 instructs the laser scanner 5 to measure the shape of the workpiece 3, and determines the shape of the workpiece 3 from the obtained measurement information. The work shape determining portion 33 is provided with a shape interpolation portion 35 as shape interpolation means. The shape interpolation part 35 interpolates the missing coordinate data of the missing part when a part of the three-dimensional coordinate data of the workpiece 3 which is the measurement information obtained by the workpiece shape determining part 33 is missing. Do the processing. The collision determination unit 34 performs a process relating to determining whether or not the tool 2 and the workpiece 3 collide with each other. The connection interface 32 may be a known one such as ORiN (registered trademark).

3 is a diagram illustrating a relationship between the laser scanner 5 and the workpiece 3. The laser scanner 5 is attached at the installation angle a with respect to the main axis AX (Z-axis direction) of the tool 2. In addition, since the laser scanner 5 emits a spot laser and a line laser, the measurement ranges b to c of the laser scanner 5 with respect to the workpiece 3 are transferred to the laser scanner 5. Determined by the injectable scan angle. For example, in the case where the scanning angle range of the laser scanner 5 is -14.4 ° to + 14.4 °, when the mounting angle a is 30 ° and the laser scanner 5 is attached to the tool 2, the laser is The measurement ranges b to c of the scanner 5 are in a range of 15.6 ° to 44.4 ° with respect to the main axis AX. Therefore, the measurable area A by the laser scanner 5 depends on the installation angle a and the scanning angle of the laser scanner 5. In addition, the laser scanner 5 and the workpiece 3 are configured to be relatively displaceable. After changing the relative position of the laser scanner 5 and the workpiece 3, the measurement can be performed by temporarily stopping the measurement or changing the relative position. At least any one of the workpiece | work 3 and the laser scanner 5 should just be comprised so that a position change is possible.

When the workpiece 3 is three-dimensionally measured by the laser scanner 5 when the workpiece 3 is provided with a deep hole or a deep groove, a step caused by the deep hole or deep groove is generated. Becomes square with respect to a laser beam, and a part of three-dimensional coordinate data obtained may fall. 4 is a diagram illustrating a rectangular area. When the laser light L is incident on the step h, the incident angle of the laser light varies depending on the scanning angle when the incident light is incident. Regarding the height ΔZ of the step h, the rectangular areas B to C are generated in the Y-axis direction by the measurement ranges b to c of the laser scanner 5. As an example of the above-described measurement range, since the incident angle of the laser light L changes depending on the timing of the scanning angle of the laser scanner 5, the squares B and C depend on the angle of incidence but up to the square area B = ΔZ × tan (15.6). The range of is always a rectangular area irrespective of the angle of incidence, and the rectangular area is changed from the rectangular area B to the square C = ΔZ × tan (44.4) by the angle of incidence.

The shape interpolation process performed by the control part 31 of the tool collision avoidance apparatus 10 is demonstrated with reference to FIG. The shape interpolation process is executed as part of the shape measurement process of the workpiece 3 executed by the workpiece shape determining unit 33. You may use a well-known technique about the shape measurement process and the collision determination process of the to-be-processed object 3. For example, in the shape measurement process of the workpiece 3, the workpiece shape determination unit 33 gives an instruction of measurement start to the laser scanner 5, and the laser scanner 5 makes a three-dimensional measurement. The measurement information (three-dimensional coordinate data) of the measurement area is obtained, and is received by the storage device of the control unit 31. The workpiece shape determining unit 33 then determines the shape of the workpiece 3 based on the received measurement information. On the other hand, in the collision determination process, collision is determined based on the information of the determined shape. Commercially available processing simulators can be used to determine collisions. The collision determination unit 34 displays, on the monitor of the tool collision avoidance device 10, a warning message for conflicting or a safety message for not conflicting based on the determination result.

In the shape measurement processing executed by the workpiece shape determining unit 33, shape interpolation processing is executed when three-dimensional coordinate data obtained as measurement information is missing. First, the shape interpolation part 35 selects missing coordinate data from the three-dimensional coordinate data obtained by the shape measurement process in step S1. As shown in FIG. 6A, when the laser beam L is irradiated to the steps h1 to h6 generated by the convex portions 3a to 3c, the rectangular areas B1 to B3 are generated by the incident angle of the laser beam L to the workpiece 3. Moreover, in step h5, the discontinuous area B4 which the irradiated laser beam L does not reflect arises. The measurement information obtained by the laser scanner 5 is three-dimensional coordinate data, and data can be obtained at each measurement point by the laser light L sequentially emitted in a line shape from the light source of the laser scanner 5. Due to the scanning angle of the laser scanner 5 described above, unmeasured areas of the rectangular areas B1 to B3 and the discontinuous area B4 are generated in FIG. 6A, and three-dimensional coordinate data cannot be obtained.

An example of missing coordinate data is shown in FIG. FIG. 7: Allocates the mesh m divided | segmented into grid form at regular intervals on the X-Y plane in the X-axis direction and the Y-axis direction, and among the point group data which is three-dimensional coordinate data contained in each mesh m. , The maximum value of the Z-axis coordinate is added to the mesh as height information. Each mesh m has missing coordinate data D1, D2,... (Represented by reference numeral D in particular when there is no need to distinguish) may be present. The missing coordinate data D is empty coordinate data and exists as one missing coordinate data D or two or more missing coordinate data D groups. In the example of FIG. 7, the group of missing coordinate data D1 to D5 in which five missing coordinate data D is set is shown. The shape interpolation part 35 selects this missing coordinate data D. FIG. In step S1, either of the missing coordinate data D1 to the D5 group is selected. For convenience, explanation is continued as the missing coordinate data D1 is selected.

Next, the shape interpolation part 35 advances to step S2, extracts coordinate data adjacent to the missing coordinate data D1, and compares the extracted coordinate data. In this case, when several missing coordinate data D adjoins like the missing coordinate data D1-D5 group, the missing coordinate data D1-D5 is recognized as one data group, and the coordinate data adjacent to the data group is carried out. Extract In FIG. 7, the missing coordinate data D2, D3, and D5 adjacent to the missing coordinate data D1 are determined to be missing coordinate data, and the coordinate data adjacent to the missing coordinate data D2, D3, and D5 is extracted, and the adjacent missing coordinates are extracted. The extraction process is performed until the data is not extracted. As a result, in the missing coordinate data D1 to D5 group, adjacent coordinate data N1 to N14 adjacent to both sides in the X axis direction and the Y axis direction are extracted. The extracted adjacent coordinate data N1-N14 is compared, and the highest numerical value among these is determined as interpolation coordinate data which interpolates to the missing coordinate data D group. In the example of FIG. 7, the adjacent coordinate data N4 to N5 = 150 having the highest value among the extracted adjacent coordinate data N1 to N3 = 50, N4 to N5 = 150, and N6 to N14 = 100 is determined as interpolation coordinate data. do. In following step S3, the shape interpolation part 35 interpolates the interpolation coordinate data determined by step S2 to each of the missing coordinate data D1-D5 group, and complete | finishes this process. In shape interpolation process, the process of step S1-step S3 corresponds to shape interpolation means, and shape measurement process corresponds to shape determination means.

6B is a diagram for explaining the shape of the workpiece 3 formed by interpolating missing coordinate data. In addition, since FIG. 6B is demonstrated by sectional drawing on a Y-Z plane, it demonstrates by the Y-axis component mY of the mesh m divided | segmented at equal intervals in the Y-axis direction for convenience, but actually m is a mesh m on an X-Y plane Coordinate data in the mesh m is determined as three-dimensional coordinate data included in. 6B, each missing coordinate data D by the rectangular areas B1 to B3 and the discontinuous areas B4 is interpolated by the shape interpolation process. As the adjacent coordinate data adjacent to each of the non-measured areas B1 to B4, the mesh component mY located at the upper surface portion of each of the convex portions 3a to 3c has the largest value in the Z-axis direction. Each mesh component mY corresponding to B1 to B4 is interpolated as interpolation coordinate data, and is determined as in the shape shown by the thick line in FIG. 6B. In addition, since one coordinate data is determined for each mesh component mY, when an external shape having a different height is assigned to the mesh component mY, the shape is interpolated by the maximum value included in the mesh component mY. Like mY1-mY3, it may interpolate on the outer side rather than the external shape of the actual workpiece 3.

After interpolation, the shape of the workpiece 3 is determined based on the measurement information after data interpolation in the shape measurement process. In the case of the workpiece 3 having the same shape as that of FIG. 6A, the workpiece 3 is determined to have a rectangular shape as shown by the bold line of FIG. 6B, and the workpiece 3 is formed on the outer side of the workpiece 3. The shape is interpolated. The shape is interpolated so that the volume of the workpiece 3 is greater than that of the actual workpiece 3, that is, the actual shape of the workpiece 3 is increased. This "outside" concept also includes interpolation of a shape that protrudes toward the inner circumferential surface side of the recess when the recess 3 is provided in the workpiece 3. In addition, the interpolated shape and the actual external shape may be the same in the unmeasured area. The shape is interpolated by such a simple and easy process, whereby the collision between the tool 2 and the workpiece 3 can be reliably prevented. Although it is recognized as a shape larger than the actual shape of the workpiece 3, even if a warning of a collision is notified by this interpolated shape portion, only the checking operation by the operator is added to the process, and the tool 2 and the workpiece Compared to the loss due to the collision of water 3, it is a slight addition that can withstand practical use sufficiently.

This invention can be implemented in various aspects, without being limited to the form mentioned above. For example, although this shape demonstrated the shape interpolation process as a part of shape measurement process, it is not limited to this. For example, shape interpolation may be performed independently. When there is three-dimensional coordinate data having missing coordinate data, interpolation coordinate data can be interpolated to the missing coordinate data by performing shape interpolation processing. In addition, although the measurement means was demonstrated as the laser scanner 5 in this form, it is not limited to this. You may apply this invention to the various measuring means which an unmeasured area | region, such as a CCD camera, produces. In the present embodiment, adjacent coordinate data adjacent to the missing coordinate data D is acquired from all sides of the missing coordinate data D. However, the present invention is not limited thereto, and may be, for example, from all sides, and appropriate modifications are possible. The size of the mesh m may also be arbitrary and can be changed as appropriate depending on the performance.

The work piece is a concept including the case of only the work piece 3 and a case including other structures such as a jig, a table, a measuring instrument, etc. which support the work piece 3 in addition to the work piece 3. In addition, an unmeasured area | region is a concept containing square B1-B3 and discontinuous area B4.

Claims (4)

Tool collision prevention system which measures the workpiece part including the workpiece processed by the tool of a machine tool in advance, and makes a collision determination of whether the said tool and the workpiece part collide based on the measurement result. As
Measuring means for three-dimensionally measuring the shape of the workpiece;
And a shape determining means for determining the shape of the work piece based on the measurement result of the measuring means.
When the shape determining means includes an unmeasured area in which the shape of the workpiece is not measured in the measurement result of the measurement means, the shape determining means is more than the outer shape or the outline of the workpiece in relation to the unmeasured area. And a shape interpolation means for interpolating the shape of the workpiece to determine the shape of the workpiece. The method of claim 1,
In the shape interpolation means, when a part of the three-dimensional coordinate data acquired by the measurement means is missing and the missing coordinate data indicating the unmeasured area is included, the missing data is adjacent to the missing coordinate data. And interpolating coordinate data based on the absent adjacent coordinate data, and interpolating the shape of the workpiece by interpolating the interpolation coordinate data to the missing coordinate data. The method of claim 2,
And the shape interpolation means compares adjacent coordinate data groups adjacent to the missing coordinate data to determine adjacent coordinate data having a maximum value among the adjacent coordinate data groups as interpolated coordinate data. Tool collision prevention method of performing three-dimensional measurement of the workpiece | work part containing the workpiece | work processed by the tool of a machine tool in advance, and making a collision determination of whether the said tool and the workpiece | work part collide based on the measurement result. As
A measurement step of three-dimensionally measuring the shape of the workpiece;
And a shape determination step of determining the shape of the work piece based on the measurement result of the measurement step,
In the shape determining step, when the measurement result of the measurement step includes an unmeasured area in which the shape of the workpiece is not measured, the shape determination step is performed more than the external shape or the external shape of the workpiece part with respect to the unmeasured area. And a shape interpolation step of interpolating the shape of the workpiece to determine the shape of the workpiece.

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