JP5324260B2 - On-machine measurement system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an on-machine measurement system that automatically measures a three-dimensional curved surface shape of a workpiece with high measuring accuracy in a measurement result. <P>SOLUTION: The on-machine measurement system 100 includes: a machine tool 50 equipped with a main spindle 51 movable three-dimensionally in each axial direction of X, Y, and Z axes; an articulated arm type measurement device 10 disposed near the workpiece W to be measured, equipped with a plurality of joint portions 16a, 16b, and 16c which do not have motive power themselves and a plurality of arm portions 15a, 15b, and 15c, and a non-contact or contact type shape measuring head 9 disposed on a tip portion 18 thereof; a connection portion 20 mounted on the main spindle 51 where the tip portion 18 is mounted on the main spindle 51 so that the shape measuring head 9 can approach the workpiece W; and a control portion provided with a measuring route program that moves the machine tool 50 so as to reflect the shape of the connection portion 20 and to move the shape measuring head 9 to a desired position of the workpiece W to be measured. Then the workpiece W is automatically measured with high accuracy. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  The present invention relates to an on-machine measurement method, and more particularly to an on-machine measurement system that automatically measures a three-dimensional curved surface shape of a processed workpiece on a machine tool that processes a workpiece such as a mold.

  Conventionally, the curved surface shape accuracy and dimensions of a workpiece such as a die machined by a machine tool are measured by a measuring tool such as a caliper or a micrometer, and the machining accuracy is inspected. In addition, the processing accuracy is inspected by replacing the processed workpiece on a three-dimensional measuring instrument equipped with a displacement detection type measuring head. This measurement system requires manpower, takes a long time to change the workpiece, and depends on the skill of the measurement operator, and the measurement accuracy is insufficient.

  Therefore, in recent years, a measurement system has been adopted in which a measuring head is mounted on the spindle of a machine tool to measure the shape accuracy and dimensions of a workpiece after processing. Specifically, the displacement in the X, Y, and Z axis directions is detected in an on-machine measurement system that uses an NC machine tool that measures the shape accuracy and dimensions of a workpiece by attaching a measuring head to the spindle of the NC machine tool. Using a possible displacement detection type measurement head, the workpiece shape accuracy and dimensions are calculated based on the displacement amount output from the displacement detection type measurement head and the position data output from the machine tool. An on-machine measurement system that automatically measures a three-dimensional curved surface shape has been proposed. (Patent Document 1).

JP 7-204990 A

  However, in such an on-machine measurement system, the position data output from the machine tool is obtained by using the “command coordinate values (x, y, z)” of the NC (numerical control) controller that controls the machine tool. In order to read, the measurement result regarding the three-dimensional shape of the workpiece eventually depends on the position control accuracy of the machine tool, and there is a problem that the measurement accuracy is not sufficient.

  An object of the present invention is to provide an on-machine measurement system that solves the above-described problems and that can automatically measure a three-dimensional curved surface shape of a workpiece with high measurement accuracy of measurement results.

(1) An on-machine measurement system that automatically measures a workpiece to be measured on a machine tool. The machine tool has a spindle that can be moved three-dimensionally in each of the X, Y, and Z directions, and is installed near the workpiece. An articulated arm type measuring instrument having a plurality of joint parts and a plurality of arm parts that have no power per se, and a non-contact type or contact type shape measuring element provided at the tip part thereof, The joint is attached to the spindle and the tip is attached to the spindle so that the shape gauge faces the workpiece, and the shape of the joint is reflected to move the shape gauge to the desired location on the workpiece to be measured. An on-machine measurement system comprising: a control unit having a measurement path program for moving a machine.
According to the configuration of (1), from a machine tool, an articulated arm type measuring instrument provided with a non-contact type or contact type shape measuring element at the tip thereof, and a coupling part for attaching the shape measuring element to the spindle An on-machine measurement system can be configured, and the machine tool can be moved by a measurement path program reflecting the shape of the joint, and the shape measuring element can be moved to the desired location of the workpiece to be measured to measure the 3D shape of that location. . Accordingly, automatic measurement is possible, and measurement of the position of the shape measuring element is performed by an articulated arm type measuring instrument, so that measurement accuracy can be increased.
(2) The on-board measurement system according to (1), wherein the installation position of the articulated arm type measuring device is selected in advance using a measurement path program and can be confirmed in a virtual space of the control unit.
According to the configuration of (2), since the installation position of the desired articulated arm type measuring device selected using the measurement path program for moving the machine tool can be confirmed on the virtual space of the control unit, the articulated arm The installation accuracy of the type measuring device can be increased.
(3) The on-machine measurement according to (1) or (2), further comprising a laser pointer provided in the vicinity of the spindle of the machine tool, wherein the laser pointer indicates an installation position of the articulated arm type measuring instrument. system.
According to the configuration of (3), since the laser pointer indicates the installation position of the articulated arm type measuring device, the installation accuracy of the articulated arm type measuring device can be further increased.

  ADVANTAGE OF THE INVENTION According to this invention, the on-machine measuring system which can measure automatically the three-dimensional curved surface shape of a workpiece | work with the high measurement accuracy of a measurement result can be provided.

1 is a schematic diagram of an on-board measurement system according to an embodiment of the present invention. It is the schematic of the 1st modification regarding the coupling | bond part of an on-machine measuring system. It is the schematic of the 2nd modification regarding the coupling | bond part of this on-machine measuring system. It is a creation procedure flowchart of a measurement path program. It is a schematic diagram of the virtual space defined in the control unit memory. It is an operation | movement flowchart of the on-board measuring system which concerns on embodiment of this invention. It is a schematic diagram of the measurement path program developed in the virtual space. It is a schematic diagram of a template for creating a measurement path program. It is an installation position selection flowchart of an articulated arm type measuring device.

  Hereinafter, embodiments of the present invention will be described with reference to FIGS. 1 to 9.

  FIG. 1 shows a schematic diagram of an on-board measurement system 100 according to the present invention. The on-machine measurement system 100 includes an NC machine tool 50, an articulated arm type measuring instrument 10, and a coupling unit 20 that couples both. A workpiece W to be measured, which is fixed by a jig WB and processed by the NC machine tool 50, is positioned on a floor surface 5 of a machine facility (not shown) provided with the machine tool 50. An articulated arm type measuring instrument 10 is arranged on the floor surface 5 in the vicinity of the workpiece W.

  First, the NC machine tool 50 will be described. The NC machine tool 50 may be a known NC machine tool, and can be three-dimensionally moved in each of the XYZ directions by an input signal from the outside. When performing measurement, the spindle 51 of the NC machine tool 50 is connected to the distal end portion 18 of the articulated arm type measuring instrument 10 by a coupling portion 20 described later, and is configured to be able to move the distal end portion 18 three-dimensionally. The NC machine tool 50 serves as an auxiliary mechanism for the on-machine measurement system 100. Further, the strokes in the XYZ directions of the NC machine tool 50 as an auxiliary mechanism do not exceed the measurable distance of the multi-joint type arm-type measuring instrument 10 described later.

  Since the positional relationship between the NC machine tool 50 and the workpiece W is adjusted before the workpiece W is processed using the workpiece reference plane, the reference point WO, and the like, they are already associated with each other. The origin of the NC machine tool 50 in each of the XYZ directions is preferably the reference point WO of the workpiece W.

  In the vicinity of the on-board measurement system 100, particularly in a place where there is no trouble in measurement, a control unit 101 that is not shown in the figure or connected wirelessly is provided, and performs drive control, status monitoring, and data management of each component device. .

  The multi-joint type arm-type measuring instrument 10 includes a plurality of joint portions, an arm portion, a tip portion, and a shape measuring element provided at the tip portion on the measuring device body 12. Specifically, one end portion of the arm portion 15a is attached to a joint portion 16a attached to a measuring device twist movable portion 17a provided on the measuring device main body 12 that rotates infinitely. Furthermore, one end portion of the arm portion 15b is attached to the measuring instrument twist movable portion 17b that rotates infinitely attached to the other end portion of the arm portion 15a via the joint portion 16b. A measuring instrument twist movable part 17c that rotates infinitely is attached to the other end of the arm part 15b, a joint part 16c is attached to the measuring instrument twist movable part 17c, and one end of the measuring instrument hand part 15c is attached to the joint part 16c. Part is attached. A tip 18 is provided at the other end of the measuring instrument hand 15c so as to be able to rotate infinitely. A contact-type or non-contact-type shape measuring element 9 is attached to the tip 18.

  The above is the configuration of the articulated arm type measuring instrument having a degree of freedom of 7. However, for example, it may be of the type having a degree of freedom of 6 in which the tip 18 is integrated with the measuring instrument hand 15c.

  The articulated arm type measuring instrument 10 is arranged on the floor surface 5 by means of a detecting means for detecting the position in the vertical direction and an elevating platform 11 having an elevating function, and the installation height can be finely adjusted. ing.

  Here, the rotation axis of the measuring instrument main body 12 and the measuring instrument twist movable part 17a is CL1, the rotational axis of the joint part 16a is CL2, the rotational axis of the arm part 15a and the measuring instrument twist movable part 17b is CL3, and the rotation of the joint part 16b. If the axis is CL4, the rotation axis of the arm portion 15b and the measuring instrument twist movable portion 17c is CL5, the rotation axis of the joint portion 16c is CL6, and the rotation axes of the measuring instrument hand portion 15c and the tip end portion 18 are CL7, CL1 and CL2, CL2 and CL3, CL3 and CL4, CL4 and CL5, CL5 and CL6, and CL6 and CL7 are configured to be orthogonal to each other or translated from orthogonal lines.

  The multi-joint type arm type measuring instrument 10 includes position information of a part of the workpiece processing surface WS, which is a non-measurement object designated by the contact type or non-contact type shape measuring element 9, and each measuring instrument joint part 16 a, 16 b, 16c, measuring instrument twist movable parts 17a, 17b, 17c, and each angle information detected by an angle detecting mechanism (not shown) such as an encoder provided at seven positions of tip 18 and the height of lifting platform 11 (multiple The distance from the floor surface 5 of the bottom surface of the articulated arm type measuring instrument 10) can be specified. Specifically, each arm vector is calculated from the polar coordinates of each joint of the multi-joint type arm-type measuring instrument 10 and the direction of the arm, and the accurate coordinate position of the shape measuring element 9 is obtained by adding the arm vectors together. Can be calculated. The detection value of each angle detection mechanism can be output to the control unit 101 via, for example, a data output mechanism (not shown) inside the measuring instrument main body 12.

  The coupling unit 20 has the following configuration. A holder 60 having a substantially half-pipe shape is attached to the main shaft 51 of the NC machine tool 50 so as to be rotatable with respect to the main shaft 51. When the NC machine tool 50 and the articulated arm measuring device 10 are coupled, the tip 18 of the articulated arm measuring device 10 is accommodated in the holder 60, and the tip 18 is attached to the tip 18. The shape measuring element 9 is fixed to the holder 60 in a detachable manner by a stopper 61 provided on the holder 60 such that the shape measuring element 9 faces the measurement target curved surface WS of the workpiece W. The shape measuring element 9 is configured to be located at a distance Z1 on the central axis of the main shaft 51 and downward from the reference position of the main shaft 51. The distance Z1 can be selected as appropriate.

  Since the shape measuring element 9 is coupled to the main shaft 51 of the NC machine tool 50 in a known positional relationship as described above, the NC machine tool 50 is moved in three directions in the desired XYZ directions by moving the NC machine tool 50 according to an input signal. Is possible. With this configuration, the on-machine measurement system 100 moves the NC machine tool 50 by using the measurement path program P described later corresponding to the desired location of the measurement target curved surface WS of the workpiece W, thereby measuring the shape measuring element 9. The position information of the part of the measurement target curved surface WS of the workpiece W indicated by the shape measuring element 9 is acquired through the articulated arm type measuring instrument 10. Therefore, a large-scale coordinate point group is acquired by scanning the workpiece processing surface WS, which is the object to be measured, like a paint brush.

  The coupling unit 20 has been described above. However, the coupling unit that couples the NC machine tool 50 and the articulated arm type measuring instrument 10 is not limited to this, and various modifications are possible.

  FIG. 2 shows a configuration of the coupling portion 21 according to the first modification. The first modification has a spacer 70 different from the holder 60 and the stopper 61 of the coupling portion 20. The spacer 70 is a rigid body, and includes a main shaft attaching portion 71, a measuring instrument attaching portion 73, and a spacer arm portion 72 that connects them. The spindle attachment portion 71 includes a hole 75 having a substantially cylindrical inner surface, and is fixed to the spindle 51 by fitting the hole 75 to the spindle 51 and tightening a clamp (not shown) provided in the spindle attachment portion 71. Yes. The measuring instrument mounting portion 73 includes a hole 76 having a substantially cylindrical inner surface. When the NC machine tool 50 and the articulated arm type measuring instrument 10 are coupled, the tip 18 is accommodated in the hole 76, and the tip 18 is measured by the shape measuring element 9 attached to the tip 18. It is detachably fixed to the holder 60 by a clamp (not shown) provided on the measuring instrument mounting portion 73 so as to face the target curved surface WS. The spacer arm part 72 has a slider 74 in the middle thereof, and can adjust and fix the distance between the spindle attaching part 71 and the measuring instrument attaching part 73.

  The spacer 70 adjusts the position and angle of the main shaft 51 and the distance between the main shaft mounting portion 71 and the measuring device mounting portion 73 to adjust the position of the shape measuring element 9 in the XYZ directions from the main shaft reference position. For example, it can be displaced by X2, Y2, and Z2. That is, by setting the position of the spindle 51 of the NC machine tool 50 to X, Y, and Z, the position of the shape measuring element 9 can be set to X + X2, Y + Y2, and Z + Z2. Also in the first modified example, the on-machine measurement system 100 moves the NC machine tool 50 using a measurement path program P, which will be described later, according to a desired location on the measurement target curved surface WS of the workpiece W. The shape measuring element 9 can be moved by the position measuring device 9, and the position information of the part of the measurement target curved surface WS of the workpiece W instructed by the shape measuring element 9 can be acquired through the articulated arm measuring instrument 10.

  FIG. 3 shows a configuration of the coupling portion 22 according to the second modification. The coupling portion 22 according to the second modification is different from the holder 60 and the stopper 61 of the coupling portion 20 and the spacer 70 of the coupling portion 21. The θX axis rotation unit 81 for adjusting the posture of the tip end portion 18 and the θY axis A rotation unit 82 and a θZ axis rotation unit 83 are provided. Thus, the direction indicated by the shape measuring element 9 attached to the distal end portion 18 is adjusted.

  The θX-axis rotating unit 81 also serves to fix the tip 18 to the main shaft 51. That is, a θY axis rotation unit 82 is attached to a θX axis rotation unit 81 fixed to the main shaft 51 via a bracket 80, and a θZ axis rotation unit 83 is provided in the θY axis rotation unit 82. Is attached to the tip 18. According to the second modification, the on-machine measurement system 100 moves the NC machine tool 50 using a measurement path program P, which will be described later, according to a desired location on the measurement target curved surface WS of the workpiece W to be measured. As a result, the shape measuring element 9 is moved and the posture of the shape measuring element 9 is set to θX, θY, and θZ, so that the position information of the measurement target curved surface WS of the workpiece W indicated by the shape measuring element 9 can be It can be obtained through the articulated arm type measuring instrument 10.

  Further, the joint portion between the main shaft 51 and the holder 60 in the joint portion 20 of the present embodiment, the joint portion between the main shaft 51 and the spacer 70 in the joint portion 21 in the first modification example, and the first modification example. A pressure detection mechanism in each of the XYZ directions is provided at a joint portion between the main shaft 51 and the bracket 80 in the coupling portion 22, and the control unit 101 (terminal) is being executed in accordance with a signal from the pressure detection mechanism. The continuation or interruption of the three-dimensional measurement is determined. Furthermore, these joint portions are provided so as to drop off when a bending reaction force greater than a prescribed value or a reaction force due to contact with the workpiece W is applied to the tip end portion 18. Thus, consideration is given to preventing damage to the shape measuring element 9 and the articulated arm type measuring instrument 10 as much as possible.

  FIG. 4 shows a flowchart for creating the measurement path program P. FIG. 5 shows a schematic diagram of a virtual space defined in the memory of the control unit 101 (terminal). The measurement path program P is a movement path of the shape measuring element 9 corresponding to the measurement target curved surface WS to be measured. In the present invention, based on the measurement path program P, the shape measuring element 9 is moved onto the actual measurement target curved surface WS, and a three-dimensional coordinate point group of the surface shape of the measurement target curved surface WS is acquired by contact or non-contact. Is.

In addition, FIG. 5 shows a schematic diagram, but it is actually recorded in the memory as data. In this figure, 91 is a shape data group (see FIG. 1) constituting the articulated arm type measuring instrument 10 including the NC machine tool 50, the coupling parts 20, 21, 22 and the shape measuring element 9, and 92 is an actual value. Three-dimensional CAD data corresponding to the workpiece W that is the measurement object, 92S is a measurement target surface (corresponding to the measurement target curved surface WS) in the three-dimensional CAD data 92, 94 is a virtual space (a space including the entire apparatus), and 95 is Each origin of the virtual space 94 is shown.

  Hereinafter, the creation of the measurement path program P will be described with reference to this flowchart.

  First, a virtual space 94 is defined (step 41). The virtual space 94 is defined in the memory of the control unit 101 (terminal) in order to create the measurement path program P and store the coordinate point group acquired by the three-dimensional measurement. The virtual space 94 has a concept of dimensions in actual three-dimensional measurement. The origin 95 corresponds to the reference point WO of the workpiece W.

  Next, the shape data group 91 is input to the virtual space 94 as model data (step 42). The shape data group 91 includes shape data of an articulated arm type measuring device and an installation position (position based on the origin 95), shape data of an NC machine tool, etc., and an NC machine tool and an articulated type by a connecting part to be used. Data on the positional relationship with the arm-type measuring device is included. Next, the three-dimensional CAD data 92 is similarly input to the virtual space 94 (step 43).

  The control unit 101 (terminal) receives the input shape data group 91, the three-dimensional CAD data 92, the actual NC machine tool 50 X-axis, Y-axis, Z-axis position information, and angle information of each θ-axis unit. It is possible to arrange and move the shape data group 91 three-dimensionally in the virtual space 94 so as to be in an actual state. Since the shape data group 91 is created so as to have the same shape as the actual product, it is easy to collate and confirm with the actual product. Further, depending on the performance of the control unit 101, the measurement path program P can be simplified or complicated within a range that does not hinder the creation of the measurement path program P or actual three-dimensional measurement.

  When inputting the three-dimensional CAD data 92 to the virtual space 94, the work W, which is a measurement object actually measured on the machine, and the three-dimensional CAD data 92 arranged at a corresponding position in the virtual space 94 are at equal positions. Align so that they are related. Specifically, after the articulated arm type measuring instrument 10 is installed in the vicinity of the workpiece W that is an actual measurement object, an element that is a characteristic of the measurement object is extracted, and the extracted element and the corresponding 3 The three-dimensional CAD data 92 is aligned so that the positional relationship with the elements of the three-dimensional CAD data 92 matches. The elements to be extracted are combinations of a mold reference point WO, a plane, and other feature points that can grasp the positional relationship of the actual measurement object. These may be acquired automatically or manually by the shape measuring element 9 of the articulated arm type measuring instrument 10.

  The origin is determined from the information regarding the positional relationship that can be grasped, and fed back to the virtual space 94 and the articulated arm type measuring instrument 10. As a result, the coordinates between the on-board measuring system and the articulated arm type measuring instrument 10 are obtained. The system matches. Further, the origin 95 is made to correspond to the reference point WO of the workpiece W.

  Hereinafter, step 44 which is the measurement target surface extraction step of FIG. 4 will be described. In the present invention, in the three-dimensional measurement of the measurement object corresponding to the three-dimensional CAD data 92, only a predetermined surface to be measured can be three-dimensionally measured. The surface to be measured, that is, the surface to be measured can be specified by designating whether or not each element constituting the surface in the three-dimensional CAD data 92 called a surface is to be measured. (Step 44).

  FIG. 7 shows a schematic diagram when one measurement surface (surface 92S in FIG. 5) of the object to be measured in the virtual space is developed. In this figure, 90a is the definition start point of the relay point information, 91a is a shape measure in the shape data group at the definition start point 90a, 90z is the definition end point of the relay point information, and 91z is in the shape data group at the definition end point 90z. A shape measuring element, 97 is a coordinate point group, 96 is a scanning direction, 98 is a divided measurement target surface, 911 is a line laser beam in a virtual space when the shape measuring element is, for example, a non-contact type, and 912 is a projection line laser in a virtual space Light 92S indicates the measurement target surface of the three-dimensional CAD data. It is assumed that the line laser beam 911 in the virtual space and the projection line laser beam 912 in the virtual space have the same effects in the virtual space 94 as those in actual three-dimensional measurement. The steps 45 and 46 in FIG. 4 will be described below.

  First, a measurement path program creation surface is designated (step 45). The measurement path program P includes a plurality of relay point information groups for measuring while the shape measuring element 9 is moving. Next, a measurement path program P is created for the designated creation surface (step 46). Each relay point information stores position information of the tip 18 (see FIGS. 1, 2 and 3) at the relay point and movement-related information to the next relay point. The position information is made up of position information for each of the X axis, the Y axis, and the Z axis of the NC machine tool 50. The position information may be position and orientation information including angle information (hereinafter referred to as posture information) of the θX axis rotation unit 81, the θY axis rotation unit 82, and the θZ axis rotation unit 83.

  The movement-related information mainly includes the movement order of the shape measuring element 9, movement speed information, and measurement operation signals. Here, the measurement operation signal is a signal storing information on whether or not to perform three-dimensional measurement when moving to the next relay point.

  With respect to the movement speed of the shape measuring element 9 during three-dimensional measurement, in the present invention, it is desired to measure two kinds of measurement speeds, that is, when the movement speed between relay points is constant and when the scanning movement speed is constant. Use properly according to the surface. In particular, the surface to be measured is relatively undulating, and the position and orientation information is frequently changed at each relay point. Therefore, the moving speed between relay points is constant when the device operates significantly in actual three-dimensional measurement. To do. Also, these two measurement speeds may be applied as appropriate within the plane to be measured. Any measurement speed is set so as not to exceed the range of the maximum drive speed of each axis or each θ-axis rotation unit of the NC machine tool 50. Each relay point information is created so that the measurement target surface 92S is divided into arbitrary divided measurement target surfaces 98 and the position and orientation information can be measured three-dimensionally with respect to each divided measurement target surface 98.

  Relay point information capable of three-dimensional measurement with respect to an arbitrary divided measurement target surface 98 is created as follows. First, the position / orientation information is set to the “reference state”. Here, the “reference state” means that when the shape measuring element 9 is, for example, a non-contact type with respect to the divided measurement target surface 98, the line laser light from the shape measuring element 9 is perpendicular and maintains an appropriate distance. This is the position and posture of the shape measuring element 9 that can be used. In the virtual space 94, after the shape measuring element 91d is set to the “reference state”, the shape data group 91 is reconstructed correspondingly, and contact determination with the three-dimensional CAD data 92 or other three-dimensional CAD data components is performed. I do. If it is determined that the contact is made, the position / orientation information is searched so that the position does not contact the shape data group 91 and the three-dimensional CAD data 92. In this way, appropriate position and orientation information is finally determined. After determining the position and orientation information, a moving order is assigned to the relay point.

  FIGS. 8A and 8B are schematic diagrams of templates for creating the measurement path program P. FIG. In this figure, 92S is a measurement target surface of 3D CAD data, 90a is a definition start point of relay point information, 90z is a definition end point of relay point information, 97 is a coordinate point group, and 96a and 96b (solid arrow portions) are scanning directions. , 98a (dotted line arrow portion) indicate the feeding direction.

  The measurement path program P is created by applying a pattern of the measurement path program P defined in advance, a so-called template, for each measurement target surface. The template defines the definition start point 90a of the relay point information, the definition end point 90z of the relay point information, each scanning direction, and each feed direction. Each scanning direction indicates the movement of the shape measuring element 9 for actually acquiring the three-dimensional coordinate point group 97, and each feeding direction indicates the movement of the shape measuring element 9 that does not acquire the three-dimensional coordinate point group 97. Yes. Further, the feed movement amount in each feed direction may be the same as or less than the acquisition width of the three-dimensional coordinate point group 97 in each scanning direction so that the ends of the three-dimensional coordinate point group 97 overlap. . The templates are not limited to those shown in FIGS. 8A and 8B, and more templates may be prepared and applied.

  Next, the measurement path program P is evaluated (step 47).

  Each relay point is defined on the same measurement target surface 92S based on the plurality of templates. After defining the measurement path program P of the prescribed number of templates, the measurement path program P that is actually applied to the three-dimensional measurement is selected from among the measurement path programs P based on the selection criteria.

  The template selection criteria are as follows. That is, the measurement on the surface can be performed in a short time, the posture information of the shape measuring element 9 is not frequently updated, the posture information having an extremely acute angle is not, and the like. Here, when the measurement path programs P in a plurality of templates can be complementary measurement results, they are combined, reconstructed, and then selected again based on the template selection criteria.

  The above operation is applied to all measurement target surfaces that require three-dimensional measurement (step 48). When the measurement path program P is created for all measurement target surfaces, the creation is terminated.

  In actual three-dimensional measurement, the on-board measurement system acquires the three-dimensional coordinate point group 97 while moving the tip 18 according to the movement order of each relay point information of the created measurement path program P.

  FIG. 6 shows an operation flowchart of the on-board measurement system based on this embodiment. Hereinafter, the three-dimensional measurement process by the on-machine measurement system will be described with reference to FIG.

  First, initial setting of the NC machine tool is performed (step 31). This initial setting is for checking the operation of each axis or each θ-axis rotating unit of the NC machine tool 50 and for the reference point WO of the workpiece W of each axis and each θ-axis unit of the NC machine tool 50 in preparation for three-dimensional measurement. The origin is aligned. Next, initial setting of the articulated arm type measuring instrument 10 is performed (step 32). This initial setting includes an encoder operation check of the articulated arm type measuring instrument 10 and a calibration of the shape measuring element 9.

  Next, an installation position instruction of the articulated arm type measuring instrument 10 is given (step 33). Thereafter, based on the installation position instruction in step 33, the articulated arm type measuring instrument 10 is installed at the designated position, and is coupled to the NC machine tool 50 by the coupling portion (step 34). Thereafter, from the three-dimensional CAD data 92 that is the shape data of the workpiece W, and the shape data group 91 that constitutes the on-board measurement system 100 including the articulated arm-type measuring instrument 10 and the coupling unit to be used, the measurement path program P Is created (step 35). As a result, the coordinate system of the on-board measurement system 100 and the measurement coordinate system of the articulated arm type measuring device 10 are matched.

  Subsequently, three-dimensional measurement is performed based on the created measurement path program P (step 36). The measurement is finished when all the measurement target surfaces defined in step 35 are measured three-dimensionally (step 37).

  Finally, comparative evaluation between the acquired coordinate point group 97 and the three-dimensional CAD data 92S is performed (step 38). The comparative evaluation result is desirably in a display form that allows the measurer to easily grasp the difference between the two, such as visual color contouring or numerical histogram.

  FIG. 9 shows a flowchart for selecting the installation position of the articulated arm type measuring instrument. First, a plurality of installation candidate positions in the vicinity of the workpiece W are set in the virtual space 94 (step 131). Each of these installation candidate positions is defined by numerical values of the X axis and the Y axis with respect to the origin 95 of the virtual space 94, and the number can be appropriately selected in consideration of the calculation load. Next, the measurement route program P is calculated for each installation candidate position (step 132). The measurement path program P here may be the same as step 41 to step 48 shown in FIG. 4, but may be simplified as long as it does not interfere with the selection of the optimum installation position in step 133. Finally, the optimum installation position of the articulated arm type measuring device is selected (step 133). In addition to being able to measure all the measurement target surfaces defined in step 35 described above in three dimensions, the optimal installation position selection criteria include, for example, the cumulative value of the moving speed between relay points (described in FIG. 7) and the distance between relay points. The standard may be to calculate the required time from the cumulative value of the moving distance to the end of measurement at each installation candidate position, and to select the shortest installation candidate position as the optimum installation position.

  The above-described installation position selection of the articulated arm type measuring device shown in FIG. 9 can be performed at the timing of the installation position instruction of the articulated arm type measuring device 10 in step 33 described above. For example, it may be performed while the NC machine tool 50 is machining the workpiece W). The installation position instruction in step 33 can be performed by displaying the position on the control unit 101, but can also be performed by a pointer indicating the position on the floor 5. For example, as shown in FIG. 1, the pointer is installed near the spindle 51 of the NC machine tool 50, and the NC machine tool 50 is moved based on an instruction from the control unit 101. The floor 5 can be configured to point at the light spot.

  In addition, this invention is not limited to the above-mentioned embodiment, The deformation | transformation in the range which can achieve the objective of this invention, improvement, etc. are included in this invention.

DESCRIPTION OF SYMBOLS 9 Shape measuring element 10 Articulated arm type measuring device 15a, 15b, 15c Arm part 16a, 16b, 16c Joint part 18 Tip part 20, 21, 22 Connection part 50 Machine tool 51 Spindle 94 Virtual space 100 On-machine measurement system 101 Control unit 102 Laser pointer P Measurement path program W Workpiece (measurement target)

Claims (3)

An on-machine measurement system that automatically measures a workpiece to be measured on a machine tool,
The machine tool includes a spindle that is three-dimensionally movable in each XYZ axis direction,
A multi-joint type that is installed in the vicinity of the workpiece and has a plurality of joint portions and a plurality of arm portions that have no power per se, and a non-contact or contact-type shape measuring element is provided at the tip portion An arm-type measuring instrument;
A coupling portion that is attached to the main shaft and attaches the tip to the main shaft so that the shape measuring element faces the workpiece;
A control unit comprising a measurement path program for reflecting the shape of the coupling part and moving the machine tool so as to move the shape measuring element to a desired position of the workpiece to be measured;
Equipped with a,
The on- board measurement system in which the installation position of the articulated arm type measuring device is selected in advance using the measurement path program and can be confirmed in a virtual space of the control unit . The on-machine measurement system according to claim 1, further comprising a laser pointer provided in the vicinity of the main spindle of the machine tool, wherein the laser pointer indicates an installation position of the articulated arm type measuring instrument. An on-machine measurement system that automatically measures a workpiece to be measured on a machine tool,
The machine tool includes a spindle that is three-dimensionally movable in each XYZ axis direction,
A multi-joint type that is installed in the vicinity of the workpiece and has a plurality of joint portions and a plurality of arm portions that have no power per se, and a non-contact or contact-type shape measuring element is provided at the tip portion An arm-type measuring instrument;
A coupling portion that is attached to the main shaft and attaches the tip to the main shaft so that the shape measuring element faces the workpiece;
A control unit comprising a measurement path program for reflecting the shape of the coupling part and moving the machine tool so as to move the shape measuring element to a desired position of the workpiece to be measured;
Equipped with a,
An on- machine measurement system further comprising a laser pointer provided in the vicinity of the spindle of the machine tool, wherein the laser pointer indicates an installation position of the articulated arm type measuring instrument .

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