JP2000161942A - Measuring machine and method for deciding its moving path - Google Patents

Abstract

PROBLEM TO BE SOLVED: To extensively improve the measuring efficiency of a measuring machine by shortening the moving distance of the measurement probe. SOLUTION: An offset shape generating section 64 inputs the information on the definition of a work, having target points to be measured from a CAD system, etc., and generates an offset shape by having the external surface of the work shift outward by a prescribed distance. A moving path generating section 65 inputs information on the target points to be measured and decides on the moving path so that a measuring probe measures the target points, while the probe moves along the offset shape generated by means of the section 64. The decided moving path is registered in a part program.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a measuring machine for determining a moving path for measuring an object to be measured, such as a probe of a coordinate measuring machine, and a method for determining the moving path.

[0002]

2. Description of the Related Art In an off-line teaching system of a coordinate measuring machine, measurement information such as a measurement target point is added to CAD data of an object to be measured, and a movement path of a probe is generated based on the CAD data and the measurement information. That has been done. A point to be considered when forming the movement path is that the probe and the device under test do not interfere with each other during the movement of the probe. For this reason, conventionally, as shown in FIG. 9, for example, a surface is formed at a position away from the most protruding position in each of the XYZ directions of the workpiece 5 to be measured by a predetermined distance α toward the outside, and formed. When the measurement of a certain measurement target point is completed with the inside of the rectangular parallelepiped consisting of the six surfaces set as a safety area, the measurement probe is once retracted to the above surface, and moved to the next measurement target point along the above surface Then, a movement path of moving the measurement probe to the next measurement target point is formed.

[0003]

However, in the above-described conventional method for determining the movement path of the measuring instrument, as shown in FIG. 9, the work 5 is separated from the most protruding position in each axial direction by a certain distance α. Since each measurement target point is measured from the surface, if many measurement target points are included at positions other than the protruding position, the distance from the surface to each measurement target point is long. In addition, there is a problem in that the measurement probe must be moved for a longer distance than necessary, resulting in a great waste of measurement time.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and provides a measuring instrument capable of shortening a moving distance of a measuring probe and greatly improving a measuring efficiency, and a method of determining a moving path thereof. Aim.

[0005]

SUMMARY OF THE INVENTION According to the present invention, there is provided a method for determining a movement path of a measuring instrument, wherein a movable element for detecting a measurement value is set in advance for an object having a measurement target point to be measured. In a moving path determination method of a measuring machine for measuring the object to be measured by relatively moving along a path, an offset shape in which an outer surface of the object to be measured is offset outward by a predetermined distance is created. The moving path is determined so that the measurement target point is measured while the movable element moves along the offset shape.

In the measuring instrument according to the present invention, a movable element for detecting a measured value relatively moves along a predetermined moving path with respect to an object having a measurement target point to be measured. In the measuring device for measuring the object to be measured, by inputting definition information for specifying the shape of the object to be measured, an offset shape is generated by offsetting the outer surface of the object to be measured outward by a predetermined distance. Offset shape generation means, inputting information of the measurement target point to be measured, and measuring the measurement target point while the movable element moves along the offset shape generated by the offset shape generation means. Moving path generating means for determining a moving path.

According to the present invention, an offset shape is prepared by offsetting the outer surface of the object to be measured outward by a predetermined distance, and the measurement target point is measured while the movable element moves along the offset shape. Since the moving path is generated as described above, the movable element can be moved while maintaining a substantially constant distance from the outer surface of the object to be measured, and a useless moving distance does not occur in the moving path. For this reason, efficient measurement becomes possible.

The generation of the offset shape can be performed using, for example, CAD data provided from the outside and specifying the shape of the object to be measured. The determined travel path is
By registering in the part program, repeat measurement of the DUT having the same shape becomes possible.

Further, when scanning is performed along the offset shape from the measurement target point A to the next measurement target point B to be measured, and the most protruding position in the offset direction is C, the movable element is defined as A After moving from the point to a position in the offset direction of C, the moving path is determined so that the movable element moves to a position corresponding to the point B while maintaining the position in the offset direction. As compared with the case where the movable element is formed completely along the shape, the moving time is shortened by the reduced deceleration and acceleration of the movable element, and more efficient measurement becomes possible.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a three-dimensional measuring system according to an embodiment of the present invention will be described with reference to the accompanying drawings. FIG. 1 is a perspective view showing a schematic configuration of this system. This three-dimensional measuring system includes a three-dimensional measuring machine 1, a drive control of the three-dimensional measuring machine 1, and a three-dimensional measuring machine 1.
A drive control device 2 for capturing necessary measurement values from the
A J / S operation panel 3 for manually operating the coordinate measuring machine 1 via the drive control device 2 and a part program for instructing a measurement procedure in the drive control device 2 are edited and executed, and the drive control device And a host system 4 having a function of performing a calculation for applying a geometric shape to the measured coordinate values taken in via the computer 2 and recording and transmitting a part program.

The coordinate measuring machine 1 is configured as follows. That is, on the anti-vibration table 10, a surface plate 11 is placed so as to coincide with a horizontal surface with its upper surface as a base surface, and an arm support 12 standing upright from both side ends of the surface plate 11.
The X-axis guide 13 is supported at the upper ends of the a and 12b. The lower end of the arm support 12a is driven in the Y-axis direction by the Y-axis drive mechanism 14, and the lower end of the arm support 12b is supported on the surface plate 11 by an air bearing so as to be movable in the Y-axis direction. . The X-axis guide 13 drives the Z-axis guide 15 extending in the vertical direction in the X-axis direction. Z
A Z-axis arm 16 is provided on the axis guide 15 so as to be driven along the Z-axis guide 15, and a contact-type probe 17 is attached to a lower end of the Z-axis arm 16. When the probe 17 comes into contact with the work 5 placed on the surface plate 11, a touch signal is output from the probe 17 to the drive control device 2, and the XYZ coordinate values at that time are output to the drive control device 2.
Is to take in.

The J / S operation panel 3 includes a joystick 31 for manually driving the probe 17 of the coordinate measuring machine 1 in the XYZ-axis directions, and a drive control device for displaying the XYZ coordinate values of the current position of the probe 17. 2 is provided with a coordinate input switch 32 for inputting to the second input. The host system 4 includes a host computer 41, a display 42, a printer 43, a keyboard 44, a mouse 45, and the like.

FIG. 2 is a block diagram of this system. The drive control device 2, the printer 43, the keyboard 44, and the mouse 45 are connected to a CPU 47 via an input / output control device 46 of the host computer 41. The CPU 47 is connected to a hard disk 48 and a memory 49, and a display control device. It is connected to the display 42 via 50. In addition, the host computer 41 has a CA
The D system 51 is also connected so that it is possible to generate a part program from design data and to send measurement results to the CAD system 51 side. The hard disk 48 stores a part program file, a part program editing / executing program file, and the like, and the offline teaching system according to the present invention is realized by these files and the hardware of the host system 4.

FIG. 3 is a functional block diagram of the off-line teaching system. This system uses CAD
The measurement information such as the measurement target points added by the system is read together with the CAD data, an optimum movement path is generated from the information, and registered as a part program. The part program file 61 is
For example, as shown in FIG. 4, DMIS (Dimentional Meas)
uring Interface Standerd) This file is described by the language specification. A file in the DMIS language is a language specification originally developed for exchanging data in both directions between the CAD and the CMM. From the CAD side,
The definition information of the geometrical shape and the information of the measurement path created as the design values are output, and the measurement result measured based on the DMIS language on the CMM is added to the file and overwritten.
It is used for returning to the AD side. The measurement procedure file in the present invention is typically described in the DMIS language, but a file created in another language can also be used as long as the file contains definition information of the measurement target. Needless to say.

The part program file 61 includes definition information for defining a geometric shape of the workpiece 5 to be measured in a three-dimensional space, and a moving path for the defined geometric shape to a measurement target point. And measurement procedure information that specifies whether to obtain measurement point coordinate values by approach. The definition information includes a boundary expression for expressing a solid model, CSG (Constructive Solid Geometr
y) An expression form such as an expression or a hybrid type (boundary expression / CGS) using them in combination is known. As shown in FIG. 5, the boundary representation method has an advantage that any complex shape can be dealt with by defining a solid model by using coordinate values of boundary surfaces, edges, vertices, and the like constituting the solid model. The CGS method is a method of expressing a solid model by defining basic solids and combining them by a set operation as shown in FIG. 6, and has an advantage that the data structure is simple. The example in FIG. 4 is an example in which a solid model is expressed using a hybrid type, and is composed of element definition information and boundary definition information. These definition information may be directly provided from the CAD system 51, for example, or may be converted by the part program editing / executing unit 62 based on the CAD data from the CAD system 51.

The part program editing / execution unit 62
A function of creating definition information and an optimal movement path based on CAD data and measurement information from the AD system 51; and a part program file 61 read based on input information input by an input unit 63 including a keyboard 44 and a mouse 45. , A function of reading the part program file 61 and controlling the drive controller 2 based on the measurement procedure information described in the file, and a function of additionally overwriting the measurement result in the part program file 61. . Offset shape generator 64
Creates an offset shape in which the surface of the measurement target is offset outward by a predetermined distance based on the CAD data from the CAD system 51. When the definition information of the part program is changed, the offset shape generation unit 64 generates an offset shape again from the changed definition information. The movement path generation unit 65 generates a movement path of the probe 17 based on the measurement information read from the CAD system 51 via the part program editing / execution unit 62 and the offset shape generated by the offset shape generation unit 64. , Convert the generated movement path into the measurement procedure information of the part program and edit the part program /
It has a function of outputting to the execution unit 62.

FIG. 7 is a flowchart showing a procedure for generating a moving path using this system, and FIG.
It is sectional drawing of the workpiece | work 5 for demonstrating the procedure. First, the offset shape generation unit 64 generates an offset shape offset by a certain distance from the outer surface of the work 5 based on the definition information of the work 5 generated from the CAD data (S1). The offset shape is, in the example of FIG.
As shown by broken lines, each surface of the work 5 has a surface shifted outward by α, indicating the limit of the safe movement area. As a method of generating an offset shape, an offset method for a ball end mill applied in CAD / CAM or the like can be used. Since the definition information is information capable of generating a solid model, generation of an offset shape is easy.

Next, the measurement target point is projected on a surface constituting an offset shape (hereinafter, referred to as an "offset surface"), and a point A projected on the surface is obtained (S2). Subsequently, the next measurement target point is similarly projected on the offset plane, and a point B projected on the plane is obtained (S3). Then, the point A is scanned from the point A to the point B on the offset plane, and the position that protrudes most in the offset direction is defined as C (S4). If the position of the point A in the offset direction does not protrude beyond the point C, the point A is shifted to the position of the point C, and a movement path is formed from the point to the point B (S6). Also, A
If the position of the point is equal to C, a path that moves to the point B while maintaining the position of the point A in the offset direction is formed (S7). Then, the processing from step S2 is repeated until the final measurement target point is reached.

For example, in the example of FIG. 8, a point A is obtained by projecting the measurement target point P1 of FIG.
When a moving path is formed from 1 to a point B1 obtained by projecting the measurement target point P2 on the offset figure D, the moving path is defined as A1 to B1.
Since the highest position C1 at the time of scanning is equal to the height of A1, a moving path is formed with the height of the point A1 as shown in FIG. On the other hand, a point A2 obtained by projecting the measurement target point P3 in FIG.
Therefore, when a moving path is formed at the point B2 where the measurement target point P4 is projected on the offset figure D, the highest position C2 when scanning from A2 to B2 is higher than the height of A2, and therefore, FIG. As shown in), a shift path from point A2 to height C2 is generated, and a movement path from that point to B2 is generated.

According to this system, the moving path of the probe is formed along the offset plane separated from the respective surfaces of the work 5 by a fixed distance α, so that the useless moving distance is reduced. However, in this system, when the measurement probe is moved from the measurement target point P3 to P4 in FIG. 9A instead of forming all the movement paths along the offset plane, the movement path is moved along the offset shape. When the direction change is made four times when the path is formed, the direction is temporarily moved to the offset position corresponding to the next measurement target point beyond the offset plane, so that the direction is changed as shown in FIG. The conversion is performed only twice, and the measurement efficiency can be further improved.

[0021]

As described above, according to the present invention, an offset shape is prepared by offsetting the outer surface of the object to be measured outward by a predetermined distance, and measurement is performed while the movable element moves along the offset shape. Since the moving path is generated so as to measure the target point, the movable element can be moved along the outer surface of the object to be measured, so that the moving path does not have a useless moving distance, and the efficiency is improved. This has the effect of enabling good measurement.

[Brief description of the drawings]

FIG. 1 is an external perspective view illustrating a configuration of a three-dimensional measurement system according to an embodiment of the present invention.

FIG. 2 is a block diagram showing a signal / information transmission system of the measuring instrument.

FIG. 3 is a functional block diagram related to determination of a movement path of the measuring device.

FIG. 4 is a diagram showing an example of a part program generated by the measurement system.

FIG. 5 is a diagram for describing a method of expressing a device under test handled by the measurement system using a boundary expression method.

FIG. 6 is a diagram showing a C of an object to be measured handled by the measurement system.
FIG. 3 is a diagram for explaining an expression method by the GS method.

FIG. 7 is a flowchart showing a procedure for determining a movement path using the measurement system.

FIG. 8 is a diagram illustrating a procedure for determining the movement path.

FIG. 9 is a diagram for explaining a conventional moving path determination method.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Coordinate measuring machine, 2 ... Drive control device, 3 ... J / S operation panel, 4 ... Host system, 5 ... Work.

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Claims (5)

[Claims] 1. Measurement of an object to be measured by moving a movable element for detecting a measured value relative to an object having a measurement target point to be measured along a predetermined moving path. In the method of determining a movement path of a measuring device, an offset shape is created by offsetting an outer surface of the object to be measured outward by a predetermined distance, and the measurement target is moved while the movable element moves along the offset shape. A moving path determination method for a measuring machine, wherein a moving path is determined so as to measure points. 2. The moving path determination of a measuring machine according to claim 1, wherein CAD data for specifying the shape of the object to be measured is provided from outside, and the offset shape is generated based on the CAD data. Method. 3. The method according to claim 1, wherein the determined moving path is registered in a part program. 4. Scanning along the offset shape from a measurement target point A to a measurement target point B to be measured next, and setting the most protruding position in the offset direction to C
Then, after moving the movable element from the point A to the position in the offset direction of C, the moving path is determined so that the movable element moves to the position corresponding to the point B while maintaining the position in the offset direction. The method according to any one of claims 1 to 3, wherein the moving path of the measuring machine is determined. 5. A measurement of an object to be measured by moving a movable element for detecting a measured value relative to an object having a measurement target point to be measured along a predetermined moving path. An offset shape generating means for inputting definition information for specifying the shape of the measured object and generating an offset shape by offsetting an outer surface of the measured object outward by a predetermined distance; and Movement path generation for inputting information of a measurement target point to be determined and determining a movement path so as to measure the measurement target point while the movable element moves along the offset shape generated by the offset shape generation means. And a measuring device.