Uncertainty estimation method and program

Abstract

To improve accuracy of estimation of measurement uncertainty of a three-dimensional measurement instrument when a ram axis stylus offset, an ambient temperature, or the like is different from a value described in a product specification.SOLUTION: A method for estimating uncertainty includes an acquisition step, a calculation step, and an estimation step. In the acquisition step, a plurality of first variables that are a plurality of variables included in a function showing a relation between a measurement dimension and a maximum allowable length measurement error when a predetermined measurement conditions value of use environment of a three-dimensional measurement machine 100 or a three-dimensional measurement machine 100 is a first value and a plurality of second variables that are a plurality of variables when the measurement conditions value is a second value are acquired. In the calculation step, the maximum allowable length measurement error corresponding to a third value is calculated by calculating a plurality of variables when the measurement conditions value is a third value based on the plurality of first variables when the measurement conditions value is the first value and the plurality of second variables when the measurement conditions value is the second value. In the estimation step, measurement uncertainty of the three-dimensional measurement machine is estimated based on the maximum allowable length measurement error.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a method and a program for estimating measurement uncertainty of a coordinate measuring machine. [Background technology]

[0002] A method for estimating the measurement uncertainty of a coordinate measuring machine using the maximum allowable length measurement error of the coordinate measuring machine has been proposed (for example, Patent Document 1). The maximum allowable length measurement error of a coordinate measuring machine is described in, for example, the product specifications of the coordinate measuring machine (for example, Non-Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2002-267436 A [Non-patent literature]

[0004] [Non-Patent Document 1] "Japanese Industrial Standards JIS. B 7440-2:2013 (ISO 10360-2:2009). Product Geometrical Characteristics Specification (GPS) - Coordinate Measuring Machine (CMM). Acceptance Inspection and Periodic Inspection - Part 2: Length Measurement", 4 pages, [online], Internet<URL: https: / / kikakurui.com / b7 / B7440-2-2013-01.html> [Accessed July 16, 2020] Summary of the Invention [Problem to be solved by the invention]

[0005] The product specifications for CMMs written in accordance with Non-Patent Document 1 state a function for calculating the maximum allowable length measurement error when measurement condition values ​​such as the ram axis stylus offset or ambient temperature are set to predetermined values. The method described in Patent Document 1 has the problem that if the ram axis stylus offset or ambient temperature differs from the values ​​stated in the product specifications, a difference occurs between the value calculated for the maximum allowable length measurement error using this function and the actual characteristics of the CMM, reducing the accuracy of estimating the measurement uncertainty of the CMM.

[0006] The present invention has been made in consideration of the above circumstances, and has as its object to provide an uncertainty estimation method and program that improve the accuracy of estimating the measurement uncertainty of a coordinate measuring machine when the ram axis stylus offset, ambient temperature, etc. differs from the values ​​stated in the product specifications. [Means for solving the problem]

[0007] An uncertainty estimation method according to a first aspect of the present invention comprises an acquisition step of acquiring a plurality of first variable values, which are a plurality of variable values ​​included in a function indicating the relationship between a measurement dimension and a maximum allowable length measurement error when a predetermined measurement condition value of a three-dimensional measuring machine or an environment in which the three-dimensional measuring machine is used, is a first value, and a plurality of second variable values, which are a plurality of variable values ​​when the measurement condition value is a second value; a calculation step of calculating a maximum allowable length measurement error corresponding to a third value by calculating a plurality of variable values ​​when the measurement condition value is a third value based on the plurality of first variable values ​​when the measurement condition value is the first value and the plurality of second variable values ​​when the measurement condition value is the second value; and an estimation step of estimating the measurement uncertainty of the three-dimensional measuring machine based on the calculated maximum allowable length measurement error.

[0008] In the obtaining step, the plurality of first variable values, which are the plurality of variable values ​​included in the function indicating the relationship between the measurement dimension and the maximum allowable length measurement error when the ram shaft stylus offset as the measurement condition value is the first value, and the plurality of second variable values, which are the plurality of variable values ​​when the ram shaft stylus offset is the second value, may be obtained, and in the calculating step, the plurality of variable values ​​when the ram shaft stylus offset is a third value may be calculated based on the plurality of first variable values ​​when the ram shaft stylus offset is the first value and the plurality of second variable values ​​when the ram shaft stylus offset is the second value, thereby calculating the maximum allowable length measurement error corresponding to the third value.

[0009] In the obtaining step, the plurality of first variable values ​​included in the function indicating the relationship between the measurement dimension and the maximum allowable length measurement error when the measurement condition value indicating the range is a first value, which indicates a range of temperature variation in the usage environment of the coordinate measuring machine, and the plurality of second variable values ​​when the measurement condition value indicating the range is a second value, are obtained, and in the calculating step, the plurality of variable values ​​when the measurement condition value indicating the range is the third value are calculated based on the plurality of first variable values ​​when the measurement condition value indicating the range is the first value and the plurality of second variable values ​​when the measurement condition value indicating the range is the second value, thereby calculating the maximum allowable length measurement error corresponding to the third value.

[0010] In the calculation step, the plurality of variable values ​​when the measurement condition value is the third value may be calculated by extrapolation based on the plurality of first variable values ​​when the measurement condition value is the first value and the plurality of second variable values ​​when the measurement condition value is the second value.

[0011] A second aspect of the present invention provides a program that causes a computer to execute an acquisition step of acquiring a plurality of first variable values ​​that are a plurality of variable values ​​included in a function that indicates the relationship between a measurement dimension and a maximum allowable length measurement error when a predetermined measurement condition value of a three-dimensional measuring machine or an environment in which the three-dimensional measuring machine is used is a first value, and a plurality of second variable values ​​that are a plurality of variable values ​​when the measurement condition value is a second value; a calculation step of calculating a maximum allowable length measurement error corresponding to a third value by calculating a plurality of variable values ​​when the measurement condition value is a third value based on the plurality of first variable values ​​when the measurement condition value is the first value and the plurality of second variable values ​​when the measurement condition value is the second value; and an estimation step of estimating the measurement uncertainty of the three-dimensional measuring machine based on the calculated maximum allowable length measurement error. [Effects of the Invention]

[0012] According to the present invention, it is possible to improve the accuracy of estimating the measurement uncertainty of a coordinate measuring machine when the ram axis stylus offset, ambient temperature, etc. differs from the value stated in the product specifications. [Brief explanation of the drawings]

[0013] [Figure 1] FIG. 1 is a diagram showing the relationship between the measurement dimension and the maximum allowable length measurement error used to estimate the uncertainty of measurement by a coordinate measuring machine. [Figure 2] FIG. 1 is a diagram illustrating a configuration of a three-dimensional measuring machine. [Figure 3] FIG. 10 is a diagram showing an example of a change in ram axis stylus offset. [Figure 4] FIG. 10 is a diagram showing the relationship between the ram axis stylus offset and the variable value. [Figure 5] 10A and 10B are diagrams illustrating an example of calculation of a variable value by a calculation unit. [Figure 6] FIG. 10 is a diagram showing an example in which A1=A2 in the product specifications stored in the storage unit. [Figure 7] 10 is a flowchart showing a processing procedure for estimating the uncertainty of measurement by a three-dimensional measuring machine. [Figure 8] 10A and 10B are diagrams illustrating an example of calculation of a variable value by a calculation unit. DETAILED DESCRIPTION OF THE INVENTION

[0014] First Embodiment [Overview of 3D measuring machines] A coordinate measuring machine according to a first embodiment measures the three-dimensional shape of a measurement target. The coordinate measuring machine estimates measurement uncertainty, which quantitatively indicates the degree of variation in the measurement results of the three-dimensional shape obtained by the coordinate measuring machine. Some coordinate measuring machines estimate the measurement uncertainty of the coordinate measuring machine by a known method using, for example, the maximum allowable length measurement error (see, for example, Patent Document 1).

[0015] Figures 1(a) to 1(c) show the measured dimension D m and the maximum allowable length measurement error E used to estimate the measurement uncertainty by a CMM. L、MPE The horizontal axis of FIG. 1(a) is the measured dimension D m The vertical axis of FIG. 1(a) represents the maximum allowable length measurement error E when the ram axis stylus offset L is the first value L1. L1、MPE Measured dimension D m is the distance between two points on the object measured, for example, by measuring the object using a coordinate measuring machine. m The unit is millimeters.

[0016] The maximum allowable length measurement error is calculated using the following formula (1). E L、MPE =±(A L +D m / K L )(Formula 1) In (Equation 1), E L、MPE is the maximum allowable length measurement error. A L and 1 / K L is a positive variable value provided by the manufacturer of the coordinate measuring machine, and varies depending on measurement condition values ​​such as the ram axis stylus offset L.

[0017] Variable value AL represents the intercept at the measurement dimension of 0 of the function that shows the relationship between the measurement dimension of the CMM and the maximum allowable length measurement error. L is a value that represents the proportionality coefficient of the measurement error that changes in proportion to the measurement dimension of the function that shows the relationship between the measurement dimension of the CMM and the maximum allowable length measurement error. In the example of Figure 1(a), the variable value A when the ram axis stylus offset L is the first value L1 L Let A1 be the first variable value.

[0018] Figure 1(b) shows the maximum allowable length measurement error E when the ram axis stylus offset L is the second value L2. L2、MPE The change in the variable value A when the ram axis stylus offset L is the second value L2 is shown. L Let A2 be the second variable value.

[0019] For example, when the ram axis stylus offset L is a first value L1, A in (Equation 1) L =2, K L = 500. In this case, A L =2, K L Substituting =500, E L1、MPE =±(2+D m / 500)(Formula 2) The maximum allowable length measurement error E corresponding to (Equation 2) L1、MPE The change in the measured dimension D is shown in Figure 1(c). m If the distance is 500 mm, then D m = 500 to find the maximum allowable length measurement error E L1、MPE can be calculated as ±3 micrometers.

[0020] The coordinate measuring machine acquires from a storage unit a plurality of first variable values ​​(A1, 1 / K1) included in (Equation 1) when a measurement condition value such as a ram axis stylus offset is a first value, and a plurality of second variable values ​​(A2, 1 / K2) included in (Equation 1) when the measurement condition value is a second value. The coordinate measuring machine calculates a plurality of variable values ​​(A3, 1 / K3) when the measurement condition value is a third value using the acquired plurality of first variable values ​​(A1, 1 / K1) and plurality of second variable values ​​(A2, 1 / K2). The coordinate measuring machine calculates a maximum allowable length measurement error E when the measurement condition value is the third value, based on the plurality of variable values ​​(A3, 1 / K3) when the measurement condition value is the third value. 3、MPE By calculating the uncertainty of the measurement by the coordinate measuring machine when the measurement condition value is the third value, the uncertainty of the measurement by the coordinate measuring machine is estimated.

[0021] Some CMMs can automatically change the direction in which their probes extend. Others are equipped with multiple styli that extend in different directions. When the probe orientation is changed or the stylus used for measurement is switched, the ram axis stylus offset L changes.

[0022] The CMM estimates the uncertainty of measurement by the CMM 100 corresponding to any measurement condition value, using a plurality of first variable values ​​included in (Equation 1) when the measurement condition value, such as the ram axis stylus offset, is a first value, and a plurality of second variable values ​​included in (Equation 1) when the measurement condition value is a second value. In this way, the CMM can improve the accuracy of estimating the measurement uncertainty of the CMM when the measurement condition value differs from the value stored in the storage unit as the product specifications.

[0023] [Configuration of 3D measuring machine] 2 is a diagram showing the configuration of a coordinate measuring machine 100. The coordinate measuring machine 100 includes an angle indicator 1, a display 2, a storage unit 3, and a control unit 4. The coordinate measuring machine 100 is capable of changing the orientation of the probe.

[0024] The angle indicator 1 detects the orientation of the probe. For example, the angle indicator 1 is a sensor that detects the roll angle, pitch angle, and yaw angle that indicate the orientation of the probe. The angle indicator 1 inputs the detected orientation of the probe to the control unit 4. The display unit 2 displays text and images. For example, the display unit 2 displays the measurement results of the shape of the measurement object and the estimated results of the uncertainty of measurement by the coordinate measuring machine 100.

[0025] The storage unit 3 includes a storage medium such as a ROM (Read Only Memory), a RAM (Random Access Memory), or a hard disk. The storage unit 3 stores a program executed by the control unit 4. The control unit 4 is, for example, a CPU (Central Processing Unit). The control unit 4 executes the program stored in the storage unit 3 to function as an acquisition unit 401, a calculation unit 402, an estimation unit 403, and an output unit 404.

[0026] [Get variable value] The acquisition unit 401 acquires a plurality of first variable values, which are included in a function indicating the relationship between the measurement dimension and the maximum allowable length measurement error when a predetermined measurement condition value of the coordinate measuring machine 100 or the usage environment of the coordinate measuring machine 100 is a first value. For example, the acquisition unit 401 acquires a plurality of first variable values ​​(A1, 1 / K1) included in the function of (Equation 1) when the ram shaft stylus offset L, as an example of a measurement condition value, is a first value. The first value is, for example, 0 millimeters.

[0027] The acquisition unit 401 acquires a plurality of second variable values, which are a plurality of variable values ​​when the measurement condition value is a second value. For example, the acquisition unit 401 acquires a plurality of second variable values ​​(A2, 1 / K2) included in the function of (Equation 1) when the ram shaft stylus offset L is a second value. The second value is, for example, 150 millimeters.

[0028] 3(a) and 3(b) are diagrams showing examples of changes in the ram axis stylus offset L. As shown in FIG. 3(a), a stylus 41 is attached to the tip of the probe of the coordinate measuring machine 100. The ram axis direction is indicated by an arrow. The ram axis stylus offset L is the distance between the stylus 41 and a reference point 42 in a direction perpendicular to the ram axis direction.

[0029] In the coordinate measuring machine 100, when the orientation of the probe is changed, the ram axis stylus offset L changes. For example, as shown in Figures 3(a) and 3(b), when the orientation of the probe is changed, the ram axis stylus offset changes depending on the orientation of the probe.

[0030] The first value of the ram shaft stylus offset L, the first variable value A1 in (Equation 1), and the first variable value 1 / K1 in (Equation 1) are associated and stored as product specifications in the memory unit 3. The second value of the ram shaft stylus offset L, the second variable value A2 in (Equation 1), and the second variable value 1 / K2 in (Equation 1) are associated and stored as product specifications in the memory unit 3.

[0031] The acquisition unit 401 acquires a first variable value A1 and a first variable value 1 / K1 associated in the storage unit 3 with a first value of the ram shaft stylus offset L. The acquisition unit 401 acquires a second variable value A2 and a second variable value 1 / K2 associated in the storage unit 3 with a second value of the ram shaft stylus offset L.

[0032] [Calculating variable values ​​1] The calculation unit 402 calculates multiple variable values ​​when the measurement condition value, such as the ram axis stylus offset L, is a first value, based on multiple first variable values ​​when the measurement condition value is a second value, and multiple second variable values ​​when the measurement condition value is a second value.

[0033] 4(a) and 4(b) are diagrams showing the relationship between the ram shaft stylus offset L and the variable value A. LFig. 4(b) shows the relationship between the ram axis stylus offset L and the variable value 1 / K. L This shows the relationship between

[0034] The horizontal axis of Fig. 4(a) is the ram axis stylus offset L, and the vertical axis of Fig. 4(a) is the variable value A L In the examples of Figures 4(a) and 4(b), the variable value A L and K. L The change in variable A is assumed to be linear. L and K. L The main factors that cause the change in are measurement errors caused by characteristics such as probe deflection and measurement errors of the ram shaft roll angle. These errors are expected to change roughly linearly with respect to the ram shaft stylus offset L.

[0035] Therefore, the variable value A L In Fig. 4(a), A L =A1+k a ·(L-L1)(Formula 3) Here, in the straight line in FIG. 4(a), the variable value A when the ram axis stylus offset L is the first value L1 is L is the first variable value A1, and the ram axis stylus offset L is the second value L2. L is the second variable value A2. In the example of FIG.

[0036] The calculation unit 402 calculates the slope k a of, k a =(A2−A1) / (L2−L1)(Formula 4) In this way, the calculation unit 402 calculates the variable value A corresponding to an arbitrary ram axis stylus offset L. L can be calculated using (Equation 3) and (Equation 4).

[0037] The horizontal axis of Fig. 4(b) is the ram axis stylus offset L, and the vertical axis of Fig. 4(b) is the variable value 1 / K L The variable 1 / K Lis shown in Fig. 4(b). 1 / K L =1 / K1+k K ·(L-L1)(Formula 5) In the straight line in FIG. 4(b), the variable value A when the ram axis stylus offset L is the first value L1 L is the first variable value 1 / K1, and the variable value 1 / K when the ram axis stylus offset L is the second value L2 L is the second variable value 1 / K2. In the example of FIG. 4(b), the first value L1=0.

[0038] The calculation unit 402 calculates the slope k of the straight line shown in FIG. K of, k K =(1 / K1−1 / K2) / (L2−L1)(Equation 6) Therefore, the calculation unit 402 calculates the variable value 1 / K corresponding to an arbitrary ram axis stylus offset L. L can be calculated using (Equation 5) and (Equation 6).

[0039] The calculation unit 402 calculates, by interpolation or extrapolation, multiple variable values ​​when the measurement condition value is a third value, based on multiple first variable values ​​when the measurement condition value is a first value and multiple second variable values ​​when the measurement condition value is a second value. By calculating the multiple variable values ​​when the measurement condition value is the third value, the calculation unit 402 calculates the maximum allowable length measurement error corresponding to this third value.

[0040] 5(a) and 5(b) are diagrams showing examples of calculation of variable values ​​by the calculation unit 402. FIG. 5(a) shows the relationship between the ram axis stylus offset L and the variable value A L Fig. 5(b) shows the relationship between the ram axis stylus offset L and the variable value 1 / K. L This shows the relationship between

[0041] In the example of the first embodiment, the calculation unit 402 detects a third value L3 of the ram axis stylus offset L based on the detection result of the angle indicator 1. Since L2 < L3 in the example of FIG. 5(a), the calculation unit 402 uses equations (3) and (4) to calculate, by extrapolation, the variable value A3 when the ram axis stylus offset L is the third value L3. Further, when L1 ≤ L3 ≤ L2, the calculation unit 402 uses equations (3) and (4) to calculate, by interpolation, the variable value A3 when the ram axis stylus offset L is the third value L3.

[0042] Similarly, since L2 < L3 in the example of FIG. 5(b), the calculation unit 402 uses equations (5) and (6) to calculate, by extrapolation, the variable value 1 / K3 when the ram axis stylus offset L is the third value L3. Further, when L1 ≤ L3 ≤ L2, the calculation unit 402 uses equations (5) and (6) to calculate, by interpolation, the variable value 1 / K3 when the ram axis stylus offset L is the third value L3.

[0043] The calculation unit 402 substitutes the calculated variable value A L = A3 and the variable value 1 / K L = 1 / K3 into equation (1) to calculate the maximum allowable length measurement error E L、MPE corresponding to the ram axis stylus offset L3. The calculation unit 402 notifies the estimation unit 403 of the calculated maximum allowable length measurement error E L、MPE .

[0044] [Calculation of Variable Value When the First Variable Value and the Second Variable Value are Constant] A method for calculating the variable value A when the first variable value A1 when the ram axis stylus offset acquired by the acquisition unit 401 is the first value L1 is the same as the second variable value A2 when the ram axis stylus offset is the second value L2 will be described. FIGS. 6(a) and 6(b) are diagrams showing examples in the product specifications stored in the storage unit 3 where A1 = A2. The reason why A1 = A2 in the product specifications is that, as shown in FIG. 6(a), when the true value of the variable value A L is constant, or as shown in FIG. 6(b), A L ​L The true value of changes depending on the ram axis stylus offset L, but in the product specifications, A is L In some cases, only the worst case values ​​are shown.

[0045] The calculation unit 402 calculates the variable value A as shown in FIG. L If the true value of is constant, then A for any ram axis stylus offset L L = A1 and variable value A L As shown in Figure 6(b), the variable value A L Even if the true value of A1 changes, values ​​other than the first variable value A1 and the second variable value A2 stored in the product specifications cannot be obtained. Therefore, the calculation unit 402 calculates the true value of A2 as in FIG. L It is safe to assume that is constant.

[0046] The estimation unit 403 estimates the uncertainty of the measurement by the coordinate measuring machine 100 using a known method based on the maximum allowable length measurement error calculated by the calculation unit 402 (see, for example, Patent Document 1). The estimation unit 403 notifies the output unit 404 of the estimated uncertainty of the measurement by the coordinate measuring machine 100.

[0047] The output unit 404 outputs the uncertainty of the measurement by the coordinate measuring machine 100 estimated by the estimation unit 403 to the display unit 2. For example, the output unit 404 outputs the measurement result of the object measured by the coordinate measuring machine 100 together with the measurement uncertainty corresponding to this measurement result to the display unit 2.

[0048] [Procedure for estimating measurement uncertainty using a coordinate measuring machine] 7 is a flowchart showing the processing procedure for estimating the uncertainty of measurement by the coordinate measuring machine 100. This processing procedure is started, for example, when an operation receiving unit (not shown) of the coordinate measuring machine 100 receives a user operation to instruct the start of measurement of the shape of the measurement object.

[0049] First, the acquisition unit 401 acquires a plurality of first variable values, which are included in a function that indicates the relationship between the measurement dimension and the maximum allowable length measurement error when a measurement condition value such as the ram shaft stylus offset L is a first value (S101). Next, the acquisition unit 401 acquires a plurality of second variable values, which are included in the same function when this measurement condition value is a second value (S102).

[0050] The calculation unit 402 calculates a plurality of variable values ​​when the measurement condition value is a third value, based on the plurality of first variable values ​​and the plurality of second variable values ​​(S103). The calculation unit 402 calculates a maximum allowable length measurement error corresponding to the third value, based on the plurality of variable values ​​when the measurement condition value is the third value (S104). The estimation unit 403 estimates the uncertainty of the measurement by the coordinate measuring machine 100, based on the maximum allowable length measurement error calculated by the calculation unit 402 (S105). The output unit 404 outputs the uncertainty of the measurement by the coordinate measuring machine 100 estimated by the estimation unit 403 to the display unit 2 (S106).

[0051] [Effects of the coordinate measuring machine according to the first embodiment] According to the first embodiment, the calculation unit 402 calculates a plurality of variable values ​​when the measurement condition value is a third value using a plurality of first variable values ​​and a plurality of second variable values ​​acquired by the acquisition unit 401, thereby obtaining a maximum allowable length measurement error E corresponding to the third value. L、MPE The estimation unit 403 calculates the maximum allowable length measurement error E L、MPE is used to estimate the uncertainty of the measurement by the coordinate measuring machine 100. In this way, the estimation unit 403 can improve the accuracy of estimating the uncertainty of the measurement by the coordinate measuring machine 100 when the measurement condition values ​​differ from the values ​​stored in the storage unit 3 as product specifications.

[0052] <Second embodiment> In the first embodiment, an example is described in which the predetermined measurement condition value of the coordinate measuring machine or the usage environment of the coordinate measuring machine is the ram axis stylus offset L. In the second embodiment, an example is described in which the measurement condition value indicates the range of temperature variation in the usage environment of the coordinate measuring machine 100.

[0053] The acquisition unit 401 acquires a plurality of first variable values ​​included in a function indicating the relationship between the measurement dimension and the maximum allowable length measurement error when a measurement condition value indicating the range of temperature variation in the usage environment of the coordinate measuring machine 100 is a first value. The acquisition unit 401 acquires a plurality of second variable values ​​included in this function when a measurement condition value indicating this range is a second value. In the example of the second embodiment, the range of temperature variation in the usage environment of the coordinate measuring machine 100 is expressed in the format of 20°C ± T°C, where T is the measurement condition value.

[0054] The multiple variable values ​​included in the function (Equation 1) that shows the relationship between the measurement dimension and the maximum allowable length measurement error change depending on the measurement condition value T. Since the variable values ​​included in (Equation 1) change depending on the measurement condition value T, E (T)、MPE =±(A (T) +D m / K (T) )(Formula 7) It can be rewritten as E (T)、MPE is the maximum allowable length measurement error that varies depending on the measurement condition value T. A (T) and K. (T) is a variable value that changes depending on the measurement condition value T.

[0055] The storage unit 3 stores a first value T1 of the measurement condition value T and a first variable value A included in (Equation 7) corresponding to the first value T1. (T1) and the first variable value 1 / K included in (Equation 7) (T1) The second value T2 of the measurement condition value T and the second variable value A included in (Equation 7) corresponding to the second value T2 are stored in the storage unit 3. (T2) and the second variable value 1 / K included in (Equation 7) (T2)are stored in association with each other. The measurement condition value T1 is, for example, 2°C. The measurement condition value T2 is, for example, 3°C.

[0056] The acquisition unit 401 acquires a first variable value A associated with the first value T1 in the storage unit 3. (T1) and the first variable value 1 / K (T1) The acquisition unit 401 acquires the second variable value A associated with the second value T2 in the storage unit 3. (T2) and the second variable value 1 / K (T2) The acquiring unit 401 acquires the acquired first variable values ​​(A (T1) , 1 / K (T1) ) and multiple second variable values ​​(A (T2) , 1 / K (T2) ) to the calculation unit 402.

[0057] [Calculating variable values ​​2] The calculation unit 402 calculates a plurality of first variable values ​​(A (T1) , 1 / K (T1) ) and a plurality of second variable values ​​(A (T2) , 1 / K (T2) ) based on the above, a plurality of variable values ​​are calculated when the measurement condition value indicating the range of temperature variation in the environment in which the coordinate measuring machine is used is a third value, and thereby the maximum allowable length measurement error corresponding to the third value is calculated.

[0058] 8(a) and 8(b) are diagrams showing examples of calculation of variable values ​​by the calculation unit 402. FIG. 8(a) shows an example of calculation of variable values ​​by the calculation unit 402. (T) Fig. 8(b) shows the relationship between the measurement condition value T and the variable value 1 / K. (T) The horizontal axis of FIG. 8(a) is the measurement condition value T, and the vertical axis of FIG. 8(a) is the variable value A (T) As shown in Figure 8(a), the variable value A (T) is expressed by the following formula:

number

[0059] Here, the calculation unit 402 calculates the slope k of the straight line at T1≤T shown in Fig. 8(a) aT as k aT =(A (T2) ―A (T1) ) / (T2 - T1) (Equation 10) A (0) is the variable value A when T = 0 (T) and the calculation unit 402 A (0) = A (T1) ―(A (T2) ―A (T1) ) / (T2 - T1)·T1 (Equation 11) to calculate A (0) . The calculation unit 402 can calculate the variable value A with respect to the measurement condition value T representing the temperature variation in any usage environment from (Equation 8) to (Equation 11). (T)

[0060] The horizontal axis of Fig. 8(b) is the measurement condition value T, and the vertical axis of Fig. 8(b) is the variable value 1 / K (T) . As shown in Fig. 8(a), the variable value 1 / K (T) is expressed by the following equation.

Equation

[0061] The calculation unit 402 calculates the slope k of the straight line at T < T1 shown in Fig. 8(b) KT as k KT =(1 / K (T2) ―1 / K (T1) ) / (T2 - T1) (Equation 14) 1 / K (0) ​is the variable value 1 / K(T) when T=0, and the calculation unit 402 calculates 1 / K (0) =1 / K (T1) -(1 / K (T2) -1 / K (T1) ) / (T2-T1)·T1 (Equation 15) By K (0) The calculation unit 402 calculates the variable value 1 / K for the measurement condition value T, which represents the temperature variation in an arbitrary use environment, using (Equation 12) to (Equation 15). (T) can be calculated.

[0062] [Effects of the coordinate measuring machine according to the second embodiment] According to the second embodiment, the calculation unit 402 calculates a plurality of variable values ​​when the measurement condition value indicating the range of temperature variation is a third value, using the plurality of first variable values ​​and the plurality of second variable values ​​acquired by the acquisition unit 401, thereby obtaining the maximum allowable length measurement error E corresponding to the third value. (T)、MPE The estimation unit 403 calculates the maximum allowable length measurement error E (T)、MPE is used to estimate the uncertainty of measurement by the coordinate measuring machine 100. In this way, the estimation unit 403 can improve the accuracy of estimating the uncertainty of measurement by the coordinate measuring machine 100 when the measurement condition value indicating the range of temperature variation differs from the value stored in the storage unit 3 as the product specification.

[0063] Furthermore, the method for estimating the measurement uncertainty of the coordinate measuring machine 100 according to the first embodiment may be combined with the method for estimating the measurement uncertainty of the coordinate measuring machine 100 according to the second embodiment. In this way, the estimation unit 403 can improve the accuracy of estimating the measurement uncertainty of the coordinate measuring machine 100 when the measurement condition value indicating the range of temperature variation differs from the value stored in the storage unit 3 as the product specifications and when the ram axis stylus offset L differs from the value stored in the storage unit 3 as the product specifications due to a change in the probe orientation.

[0064] The present invention has been described above using embodiments, but the technical scope of the present invention is not limited to the scope described in the above embodiments, and various modifications and changes are possible within the scope of the gist of the present invention. For example, all or part of the device can be configured by functionally or physically distributing or integrating any unit. Furthermore, new embodiments resulting from any combination of multiple embodiments are also included in the embodiments of the present invention. The effects of the new embodiments resulting from the combination also have the effects of the original embodiments. [Explanation of symbols]

[0065] 1 Angle indicator 2 Display section 3 Storage section 4. Control Unit 41 Stylus 42 Reference points 100 3D measuring machine 401 Acquisition Department 402 Calculation Unit 403 Estimation section 404 Output Section

Claims

1. an acquisition step of acquiring a plurality of first variable values ​​which are a plurality of variable values ​​included in a function indicating the relationship between a measurement dimension and a maximum allowable length measurement error when a predetermined measurement condition value of the coordinate measuring machine or the usage environment of the coordinate measuring machine is a first value stored in a storage unit as a product specification of the coordinate measuring machine, and a plurality of second variable values ​​which are the plurality of variable values ​​when the measurement condition value is a second value stored in the storage unit as a product specification of the coordinate measuring machine; a calculation step of calculating a maximum allowable length measurement error corresponding to a third value by calculating the plurality of variable values ​​when the measurement condition value is a third value that is not stored in the storage unit as a product specification of the coordinate measuring machine, based on the plurality of first variable values ​​when the measurement condition value is the first value and the plurality of second variable values ​​when the measurement condition value is the second value; an estimation step of estimating the measurement uncertainty of the coordinate measuring machine based on the calculated maximum allowable length measurement error; An uncertainty estimation method comprising:

2. In the acquisition step, the plurality of first variable values ​​are acquired as the plurality of variable values ​​included in the function indicating the relationship between the measurement dimension and the maximum allowable length measurement error when the ram shaft stylus offset as the measurement condition value is the first value, and the plurality of second variable values ​​are acquired as the plurality of variable values ​​when the ram shaft stylus offset is the second value, in the calculating step, the plurality of variable values ​​when the ram shaft stylus offset is at the third value are calculated based on the plurality of first variable values ​​when the ram shaft stylus offset is at the first value and the plurality of second variable values ​​when the ram shaft stylus offset is at the second value, thereby calculating the maximum allowable length measurement error corresponding to the third value. The uncertainty estimation method according to claim 1 .

3. In the obtaining step, the plurality of first variable values ​​included in the function indicating the relationship between the measurement dimension and the maximum allowable length measurement error when the measurement condition value indicating the range of temperature variation in the usage environment of the coordinate measuring machine is a first value, and the plurality of second variable values ​​included in the function when the measurement condition value indicating the range is a second value are obtained, In the calculation step, the maximum allowable length measurement error corresponding to the third value is calculated by calculating the plurality of variable values ​​when the measurement condition value indicating the range is the third value based on the plurality of first variable values ​​when the measurement condition value indicating the range is the first value and the plurality of second variable values ​​when the measurement condition value indicating the range is the second value. The uncertainty estimation method according to claim 1 .

4. In the calculation step, the plurality of variable values ​​when the measurement condition value is the third value are calculated by extrapolation based on the plurality of first variable values ​​when the measurement condition value is the first value and the plurality of second variable values ​​when the measurement condition value is the second value. The uncertainty estimation method according to any one of claims 1 to 3.

5. On the computer, an acquisition step of acquiring a plurality of first variable values ​​which are a plurality of variable values ​​included in a function indicating the relationship between a measurement dimension and a maximum allowable length measurement error when a predetermined measurement condition value of the coordinate measuring machine or the usage environment of the coordinate measuring machine is a first value stored in a storage unit as a product specification of the coordinate measuring machine, and a plurality of second variable values ​​which are the plurality of variable values ​​when the measurement condition value is a second value stored in the storage unit as a product specification of the coordinate measuring machine; a calculation step of calculating a maximum allowable length measurement error corresponding to a third value by calculating the plurality of variable values ​​when the measurement condition value is a third value that is not stored in the storage unit as a product specification of the coordinate measuring machine, based on the plurality of first variable values ​​when the measurement condition value is the first value and the plurality of second variable values ​​when the measurement condition value is the second value; an estimation step of estimating the measurement uncertainty of the coordinate measuring machine based on the calculated maximum allowable length measurement error; program.

Images