Error determination apparatus, error determination method, and recording medium

Abstract

The present invention relates to an error determination apparatus, an error determination method, and a recording medium. An error determination apparatus (10) for determining a measurement error occurring when a workpiece is measured by a coordinate measuring machine includes: an information acquisition section (121) for acquiring motion error information indicating a measurement result of a motion error of the coordinate measuring machine and design information of the workpiece; a measurement position designation section (122) for designating a measurement position on the workpiece based on the design information; an error determination section (123) for determining a measurement error occurring in measurement at the measurement position due to the motion error based on the motion error information; and an output section (125) for outputting the measurement error determined by the error determination section (123).

Description

Technical Field

[0001] This invention relates to an error determination device, an error determination method, and a recording medium. Background Technology

[0002] Techniques for calculating motion errors generated by coordinate measuring machines are known (e.g., see Japanese Patent Application Laid-Open No. 2015-152576). Summary of the Invention

[0003] The problem the invention aims to solve

[0004] Users of coordinate measuring machines (CMMs) sometimes estimate the motion error of the CMM and use this estimated motion error as an indicator to check the machine. However, motion error is different from the measurement error that occurs when measuring a workpiece. Therefore, there is a problem: judging the quality of a CMM based on motion error does not always lead to an appropriate judgment.

[0005] This invention focuses on these aspects, and its purpose is to improve the accuracy of reliability assessment for coordinate measuring machines.

[0006] Solution for solving the problem

[0007] According to a first aspect of the present invention, an error determination device is used to determine a measurement error occurring when a coordinate measuring machine measures a workpiece. The error determination device includes: an information acquisition unit for acquiring a) motion error information indicating a measurement result of the motion error of the coordinate measuring machine and b) design information of the workpiece; a measurement position designation unit for designating a measurement position on the workpiece based on the design information; an error determination unit for determining a measurement error occurring at the measurement position due to the motion error based on the motion error information; and an output unit for outputting the measurement error determined by the error determination unit.

[0008] The information acquisition unit can also acquire measurement condition information indicating multiple measurement conditions when the coordinate measuring machine measures the workpiece, and the error determination unit can further determine the measurement error based on one or more measurement conditions among the multiple measurement conditions indicated by the measurement condition information that affect the measurement at the measurement position.

[0009] The measurement condition information may include characteristic information indicating the characteristics of the detector used to contact the workpiece, and the error determination unit may determine the measurement error that occurs when the detector contacts the measurement position based on the characteristics of the detector.

[0010] The measurement condition information may include position information indicating the positioning of the workpiece in the coordinate measuring machine, and the error determination unit may determine the measurement error based on the motion error corresponding to the positioning indicated by the position information.

[0011] The output unit outputs the measurement error in association with each of the multiple locations on the workpiece.

[0012] The information acquisition unit also acquires tolerance information indicating the tolerance of the workpiece, and the output unit outputs a comparison result between the tolerance indicated by the tolerance information and the measurement error.

[0013] The error determination device further includes a judgment unit, which is used to determine that the measurement error is not within an acceptable range when the measurement error exceeds the tolerance of the workpiece, and to determine that the measurement error is within an acceptable range when the measurement error is equal to or less than the tolerance of the workpiece, wherein the output unit outputs the judgment result made by the judgment unit.

[0014] The error determination method according to a second aspect of the present invention is a computer-based error determination method for determining measurement errors occurring when a coordinate measuring machine measures a workpiece. The error determination method includes the following steps: acquiring a) motion error information indicating the measurement result of the motion error of the coordinate measuring machine and b) design information of the workpiece; determining a measurement position on the workpiece based on the design information; determining a measurement error occurring at the measurement position due to the motion error based on the motion error information; and outputting the determined measurement error.

[0015] According to a third aspect of the invention, a recording medium stores a program for enabling a computer to determine a measurement error occurring when a coordinate measuring machine measures a workpiece. The program enables the computer to perform functions including: acquiring a) motion error information indicating the measurement result of the coordinate measuring machine's motion error and b) design information of the workpiece; determining a measurement position on the workpiece based on the design information; determining a measurement error occurring at the measurement position due to the motion error based on the motion error information; and outputting the determined measurement error.

[0016] The effects of the invention

[0017] According to the present invention, the accuracy of judging the reliability of coordinate measuring machines can be improved. Attached Figure Description

[0018] Figure 1 This is a diagram illustrating the general outline of the error determination method according to this embodiment.

[0019] Figure 2This is a diagram illustrating an exemplary measurement error C1 determined by the error determination device 10.

[0020] Figure 3 This is a diagram illustrating the configuration of the error determination device 10.

[0021] Figure 4 This is a flowchart illustrating the operation of the error determination device 10.

[0022] [Explanation of reference numerals in the attached figures]

[0023] 10. Error Determination Equipment

[0024] 11 Storage devices

[0025] 12 controllers

[0026] 121 Information Acquisition Department

[0027] 122 Measurement Position Designation Unit

[0028] 123 Error Determination Department

[0029] 124 Judgment Department

[0030] 125 Output Section Detailed Implementation

[0031] <Summary of the error determination method according to this embodiment>

[0032] Figure 1 This is a diagram illustrating the general outline of the error determination method according to this embodiment. (Reference) Figure 1 The following are summaries: a) a method for using error determination device 10 to determine measurement errors occurring when a workpiece is measured by a coordinate measuring machine; and b) a method for determining whether there is an anomaly in the coordinate measuring machine based on the determined measurement errors.

[0033] CMM model A1 is a model used to output the measurement error of a coordinate measuring machine (CMM) when various conditions are used to measure a workpiece. When a computer executes a program, it uses CMM model A1 to output the measurement error based on the input information. Based on the input motion error information B1, design information B2, and measurement condition information B3, CMM model A1 outputs the measurement error that occurs when the coordinate measuring machine performs measurements corresponding to this information.

[0034] Motion error information B1 is information indicating the measurement results of the motion error of the coordinate measuring machine (CMM) corresponding to CMM model A1 (i.e., the CMM that is the object to be measured for error). Motion errors include, for example, a) translational errors such as scale error or perpendicularity error and b) rotational errors. Motion error information B1 includes, for example, values ​​of motion errors determined based on the results of routine inspections of the CMM.

[0035] Design information B2 is the workpiece's design information. Design information is used to specify the workpiece's geometry, length, thickness, etc., and is, for example, the workpiece's computer-aided design (CAD) data.

[0036] Measurement condition information B3 indicates the measurement conditions when a coordinate measuring machine (CMM) corresponding to CMM model A1 measures a workpiece. Measurement conditions include, for example, the structure of the CMM, the characteristics of the detectors provided to the CMM, the workpiece's positioning, the workpiece's orientation during measurement, and the measurement points on the workpiece.

[0037] Measurement error C1 is the measurement error that occurs when a coordinate measuring machine corresponding to CMM model A1 measures a workpiece due to motion errors and measurement conditions. Measurement error C1 is also the measurement error that occurs when measuring a workpiece under the conditions indicated by measurement condition information B3.

[0038] exist Figure 1 In the error determination method shown, after determining the measurement error C1, the judgment processing unit A2 compares the measurement error C1 with the tolerance indicated by the workpiece tolerance information B4 to determine whether the coordinate measuring machine is functioning properly. For example, if the measurement error C1 is greater than the tolerance, the error determination device 10 outputs a judgment result C2 indicating an anomaly in the coordinate measuring machine. By using such an error determination device 10, the accuracy of the coordinate measuring machine's reliability judgment is improved, allowing for assurance before measurement that reliable measurement results can be obtained when the coordinate measuring machine measures the geometry of the workpiece to be measured.

[0039] Figure 2 This is a diagram illustrating an exemplary measurement error C1 determined by the error determination device 10. Figure 2 (a) shows the measurement of the workpiece without any motion error. Figure 2 (b) shows the measurement of the workpiece under motion error due to yaw in the Y direction. It should be noted that, for the sake of simplicity, Figure 2 An example is shown of measuring a square workpiece W using a coordinate measuring machine comprising an X-stage XS, a Y-stage YS, and a detector P.

[0040] like Figure 2As shown in (a), when measuring workpiece W without motion error, motion error does not need to be considered when estimating the error when measuring workpiece W using a coordinate measuring machine. However, as Figure 2 As shown in (b), for example, when the XY perpendicularity changes due to yaw in the Y direction, the measurement result of workpiece W will include a motion error that can be specified based on the product of length L and rotational error θ. The measurement error C1 is determined as the product of length L and rotational error θ using CMM model A1. This product corresponds to the motion error at the position where detector P and workpiece W are in contact with each other.

[0041] <Configuration of Error Determination Device 10>

[0042] Figure 3 This is a diagram illustrating the configuration of the error determination device 10. The error determination device 10 includes a storage device 11 and a controller 12. The storage device 11 includes a storage medium such as a read-only memory (ROM), random access memory (RAM), and a hard disk. The storage device 11 stores the program to be executed by the controller 12.

[0043] For example, the controller 12 is a CPU (Central Processing Unit). The controller 12 functions as an information acquisition unit 121, a measurement position designation unit 122, an error determination unit 123, a judgment unit 124, and an output unit 125 by executing a program stored in the storage device 11. When the information acquisition unit 121, the measurement position designation unit 122, and the error determination unit 123 work together, the controller 12 functions as... Figure 1 The CMM model A1 shown. The decision unit 124 and output unit 125 are used as... Figure 1 The judgment and processing unit A2 is shown.

[0044] The information acquisition unit 121 acquires the information required to determine the measurement error C1 and output the judgment result C2. The information acquisition unit 121 acquires this information through a communication network such as a LAN (local area network).

[0045] For example, the information acquisition unit 121 acquires motion error information B1, which indicates the motion error of the coordinate measuring machine, from a computer (not shown) storing the results of routine inspections of the coordinate measuring machine. The information acquisition unit 121 also acquires design information B2 of the workpiece from a computer (not shown) storing CAD data of the workpiece. The information acquisition unit 121 outputs the motion error information B1 to the error determination unit 123 and outputs the design information B2 to the measurement position designation unit 122.

[0046] For example, the information acquisition unit 121 also acquires measurement condition information B3 from the computer (not shown) of the person measuring the workpiece, which indicates multiple measurement conditions when the coordinate measuring machine measures the workpiece. The measurement condition information B3 includes: a) characteristic information indicating the characteristics of the detector used to contact the workpiece, and b) position information indicating the positioning of the workpiece in the coordinate measuring machine. The characteristics of the detector include, for example, the size, length, orientation, and configuration of the stylus provided with the detector. The information acquisition unit 121 outputs the measurement condition information B3 to the error determination unit 123.

[0047] For example, the information acquisition unit 121 also acquires tolerance information B4, which indicates the tolerances of the workpiece, from a computer storing CAD data of the workpiece. The tolerances indicated by the tolerance information B4 include, for example, geometric tolerances such as straightness, flatness, parallelism, and perpendicularity of the workpiece. The information acquisition unit 121 outputs the tolerance information B4 to the judgment unit 124.

[0048] It should be noted that the computer storing the results of daily inspections of the coordinate measuring machine, the computer storing the CAD data of the workpiece, and the computer used by the personnel measuring the workpiece may be the same computer or different computers.

[0049] The measurement position designation unit 122 designates the measurement position on the workpiece based on the design information B2 acquired by the information acquisition unit 121. For example, the measurement position is the location of a feature point on the workpiece, such as a vertex. For example, the measurement position on the workpiece is represented by the direction and distance relative to a reference position on the workpiece. The measurement position designation unit 122 can designate the measurement position based on the measurement point indicated by the measurement condition information B3 using the design information B2. The measurement position designation unit 122 notifies the error determination unit 123 of the designated measurement position on the workpiece.

[0050] Based on motion error information B1, the error determination unit 123 determines the measurement error C1 that occurs during measurement at the measurement position due to motion error. For example, based on motion error information B1 obtained by information acquisition unit 121, the error determination unit 123 determines the measurement error C1 (such as translation error or rotation error occurring at each of the multiple measurement positions specified by measurement position designation unit 122).

[0051] For example, since the distance and direction of the detector movement change depending on the measurement position, the motion error occurring in the coordinate measuring machine varies depending on the measurement position. The error determination unit 123 specifies the distance and direction of the detector movement based on the measurement position, and determines the motion error corresponding to the specified direction and distance, thereby determining the measurement error C1 with high calculation accuracy.

[0052] The error determination unit 123 further determines the measurement error C1 based on one or more measurement conditions that affect the measurement at the measurement position from among the multiple measurement conditions indicated by the measurement condition information B3. For example, if the measurement condition information B3 includes characteristic information indicating the characteristics of the detector used to contact the workpiece, the error determination unit 123 determines the measurement error C1 that occurs when the detector contacts the measurement position based on the characteristics of the detector.

[0053] For example, the motion error occurring in a coordinate measuring machine varies depending on the position where the stylus contacts the workpiece. By specifying the position where the stylus contacts the workpiece at the measurement position based on the characteristic information of the detector, the error determination unit 123 determines the measurement error C1 at the measurement position by taking into account the stylus position where the stylus contacts the workpiece.

[0054] When the measurement condition information B3 includes position information indicating the positioning of the workpiece in the coordinate measuring machine, the error determination unit 123 can determine the measurement error based on the motion error corresponding to the positioning indicated by the position information. This positioning is represented by coordinates in a Cartesian coordinate system of space that can be measured by the coordinate measuring machine. The error determination unit 123 specifies the measurement position in a Cartesian coordinate system of space that can be measured by the coordinate measuring machine, based on the measurement position specified by the measurement position designation unit 122 and the positioning indicated by the position information.

[0055] Subsequently, the error determination unit 123 specifies the distance and direction of detector movement based on the specified measurement position. The error determination unit 123 determines the measurement error C1 at each of the plurality of measurement positions based on the length of the detector at each position, etc., specified according to the distance and direction of detector movement. The error determination unit 123 can determine the measurement error C1 at the measurement position by measuring the measurement error based on the motion error corresponding to the workpiece's positioning.

[0056] The judgment unit 124 compares the measurement error C1 determined by the error determination unit 123 with the workpiece tolerance indicated by the tolerance information B4 obtained by the information acquisition unit 121, and determines whether the measurement error C1 is within an acceptable range based on the comparison result. The judgment unit 124 compares each of the multiple motion errors included in the measurement error C1 with the workpiece tolerances corresponding to these motion errors.

[0057] Specifically, if one or more of the multiple motion errors included in the measurement error C1 exceed the tolerances of the workpieces corresponding to those one or more motion errors, the determination unit 124 determines that the measurement error C1 is outside the acceptable range. On the other hand, if each of the multiple motion errors included in the measurement error C1 is less than or equal to the tolerances of the workpieces corresponding to those multiple motion errors, the determination unit 124 determines that the measurement error C1 is within the acceptable range. The determination unit 124 notifies the output unit 125 of the determination result.

[0058] The output unit 125 outputs the measurement error C1 determined by the error determination unit 123. In this case, the output unit 125 outputs the measurement error C1 associated with each of the multiple measurement positions on the workpiece. The output unit 125 outputs the result of comparing the tolerance indicated by the tolerance information B4 with the measurement error C1. The result of this comparison is the result of the judgment unit 124's judgment on whether the measurement error C1 is within an acceptable range, and corresponds to the judgment result C2.

[0059] The output unit 125 outputs the measurement error C1 and the judgment result C2 to an information device such as a computer or smartphone, or to a coordinate measuring machine via a communication network. For example, if the error determination device 10 is composed of an information device such as a computer or smartphone, the output unit 125 displays the measurement error C1 and the judgment result C2 on a display included in the information device.

[0060] For example, by outputting or displaying the measurement error C1 and the judgment result C2 in this way, the user of the coordinate measuring machine (CMM) can know the measurement error that occurred when using the CMM to measure a workpiece and judge the reliability of the CMM. Specifically, the user of the CMM can determine whether to repair the CMM based on the judgment result of the measurement error that occurred when measuring the workpiece.

[0061] <Flowchart of Error Determination Device 10>

[0062] Figure 4 This is a flowchart illustrating the operation of the error determination device 10. The information acquisition unit 121 acquires motion error information B1 (step S11). The information acquisition unit 121 acquires design information B2 (step S12). The information acquisition unit 121 acquires measurement condition information B3 (step S13). The measurement position designation unit 122 designates the measurement position based on the design information B2 (step S14). The error determination unit 123 determines the measurement error C1 based on the measurement position designated by the measurement position designation unit 122 (step S15).

[0063] Information acquisition unit 121 acquires tolerance information B4 (step S16). If error determination unit 123 determines measurement error C1, judgment unit 124 compares the tolerance indicated by tolerance information B4 with measurement error C1. If each of the multiple motion errors indicated by measurement error C1 is equal to or less than the tolerance corresponding to each of these motion errors (Yes in S17), judgment unit 124 determines that measurement error C1 is within acceptable range and outputs "OK" as the judgment result (step S18). If one or more of the multiple motion errors indicated by measurement error C1 exceed the tolerance corresponding to these motion errors (No in S17), judgment unit 124 determines that measurement error C1 is not within acceptable range and outputs "NG" as the judgment result (step S19).

[0064] <Effect of Error Determination Device 10>

[0065] As described above, the error determination device 10 includes a measurement position designation unit 122 for specifying the measurement position of the workpiece based on design information. Then, the error determination unit 123 determines the measurement error occurring at the measurement position specified by the measurement position designation unit 122 based on motion error information. The error determination device 10 operates in this manner, and therefore, it is able to determine the measurement error in the coordinate measuring machine while taking into account motion errors that change according to the measurement position on the workpiece. The user of the coordinate measuring machine can then determine the reliability of the coordinate measuring machine based on the measurement error determined by the error determination device 10. As a result, the user using the coordinate measuring machine to measure the workpiece can a) confirm whether the coordinate measuring machine can properly measure the workpiece before measurement and b) appropriately determine whether the coordinate measuring machine needs maintenance.

[0066] The present invention is illustrated based on exemplary embodiments. The scope of the present invention is not limited to the scope described in the above embodiments, and various changes and modifications can be made within the scope of the present invention. For example, all or part of the device can be configured to be functionally or physically distributed and integrated in any unit. Furthermore, exemplary embodiments of the present invention include new exemplary embodiments generated by any combination of all or part of the device. The effects of the new embodiments resulting from such combinations have the effects of the original embodiments.

Claims

1. An error determination device for determining measurement errors occurring during workpiece measurement using a coordinate measuring machine, the error determination device comprising: The information acquisition unit is used to acquire a) motion error information indicating the measurement result of motion error caused by at least one of the scale error, translation error and rotation error when measured in advance at multiple positions in the space that can be measured by the coordinate measuring machine; b) workpiece design information; and c) position information indicating the setting position of the workpiece in the coordinate measuring machine. A measurement position designator is used to designate the measurement position on the workpiece based on the design information; An error determination unit is used to determine, with reference to the motion error information, the measurement error occurring at the contact position due to the motion error, wherein the motion error is an error occurring at the contact position between the probe of the detector and the workpiece in a Cartesian coordinate system of a space that can be measured by the coordinate measuring machine, determined based on the measurement position specified by the measurement position designation unit and the setting position obtained by the information acquisition unit. as well as The output unit is used to output the measurement error determined by the error determination unit.

2. The error determination device according to claim 1, wherein, The information acquisition unit also acquires measurement condition information indicating multiple measurement conditions when the coordinate measuring machine measures the workpiece, and The error determination unit further determines the measurement error based on one or more measurement conditions among the plurality of measurement conditions indicated by the measurement condition information that affect the measurement at the measurement location.

3. The error determination device according to claim 2, wherein, The motion error is a rotational error. The measurement condition information includes characteristic information indicating the length of the stylus used to contact the workpiece, and The error determination unit determines the measurement error that occurs when the stylus contacts the measurement position by multiplying the length of the stylus by the rotational error at the contact position.

4. The error determination device according to any one of claims 1 to 3, wherein, The information acquisition unit acquires the motion error information, which is the measurement result of the motion error contained in the daily inspection results of the coordinate measuring machine stored in the instruction computer.

5. The error determination device according to any one of claims 1 to 3, wherein, The output unit outputs the measurement error in association with each of the multiple locations on the workpiece.

6. The error determination device according to any one of claims 1 to 3, wherein, The information acquisition unit also acquires tolerance information indicating the tolerance of the workpiece, and The output unit outputs a comparison result between the tolerance indicated by the tolerance information and the measurement error.

7. The error determination device according to claim 6, further comprising: The judgment unit is configured to determine that the measurement error is outside the acceptable range when the measurement error exceeds the workpiece tolerance, and to determine that the measurement error is within the acceptable range when the measurement error is equal to or less than the workpiece tolerance, wherein... The output unit outputs the judgment result made by the judgment unit.

8. A computer-based error determination method for determining measurement errors occurring during workpiece measurement using a coordinate measuring machine, the error determination method comprising the following steps: Acquire a) motion error information indicating the measurement results of motion errors caused by at least one of scale error, translation error, and rotation error when pre-measured at multiple locations in the space that can be measured by the coordinate measuring machine; b) workpiece design information; and c) position information indicating the setting position of the workpiece in the coordinate measuring machine. The measurement positions on the workpiece are determined based on the design information; The measurement error occurring at the contact position due to the motion error is determined by referring to the motion error information, wherein the motion error is the error occurring at the contact position between the probe of the detector and the workpiece in a Cartesian coordinate system in a space that can be measured by the coordinate measuring machine, based on the specified measurement position and the acquired setting position. as well as Output the determined measurement error.

9. A recording medium storing a program for enabling a computer to determine measurement errors occurring during workpiece measurement on a coordinate measuring machine, the program enabling the computer to perform functions including: Acquire a) motion error information indicating the measurement results of motion errors caused by at least one of scale error, translation error, and rotation error when pre-measured at multiple locations in the space that can be measured by the coordinate measuring machine; b) workpiece design information; and c) position information indicating the setting position of the workpiece in the coordinate measuring machine. The measurement positions on the workpiece are determined based on the design information; The measurement error occurring at the contact position due to the motion error is determined by referring to the motion error information, wherein the motion error is the error occurring at the contact position between the probe of the detector and the workpiece in a Cartesian coordinate system in a space that can be measured by the coordinate measuring machine, based on the specified measurement position and the acquired setting position. as well as Output the determined measurement error.

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