Generation of Measurement Strategy for Measuring a Measurement Object

Abstract

A method for determining a measurement strategy for measuring a measurement object includes determining a test element of the measurement object. There is an automated test for the test element as to whether there is an applicable measurement rule in a measurement rule set of measurement rules defined in advance. An applicable measurement rule is added to a new measurement strategy or the test element-specific measurement rule of an existing measurement strategy is altered based on an applicable measurement rule. The measurement rules of the measurement rule set are determined by virtue of a measurement rule and at least one test criterion in respect of the applicability thereof being set for a test element by a user or in (partly) automated fashion. The measurement rule defines at least one parameter for measuring the test element.

Claims

1. A method for determining a measurement strategy for measuring a measurement object comprising: determining a test element of the measurement object, wherein there is an automated test for the test element as to whether there is an applicable measurement rule in a measurement rule set of measurement rules defined in advance, wherein an applicable measurement rule is added to a new measurement strategy or the test element-specific measurement rule of an existing measurement strategy is altered based on an applicable measurement rule, wherein the measurement rules of the measurement rule set are determined by virtue of a measurement rule and at least one test criterion in respect of the applicability thereof being set for a test element by a user or in (partly) automated fashion, and wherein the measurement rule defines at least one parameter for measuring the test element.

2. The method of claim 1 wherein a test criterion is defined in such a way that testing the test criterion evaluates at least one of: a geometric property of the test element; a variable dependent on a geometric property of the test element; an ambient condition; a predetermined tolerance; a measuring device type; a sensor type; a build state of the measurement object; and a measurement quality of a preceding measurement of the measurement object.

3. The method of claim 2 further comprising, in order to test applicable measurement rules, determining at least one of: a geometric property of the test element; a variable dependent on a geometric property of the test element; an ambient condition; a predetermined tolerance; a measuring device type; a sensor type; a build state of the measurement object; and a measurement quality of a preceding measurement.

4. The method of claim 1 wherein: test element-specific properties are respectively assigned to different test elements; and a test criterion is defined for a test element in such a way that only at least one test element-specific property of the test element or a variable dependent thereon is evaluated during a test of the test criterion.

5. The method of claim 1 wherein at least two test criteria, which should be tested in at least two successive test steps, are defined for testing the applicability of a measurement rule for a test element.

6. The method of claim 5 wherein the test criterion to be tested in a subsequent test step is defined based on at least one already tested test criterion.

7. The method of claim 5 wherein the test criterion to be tested in a subsequent test step is defined based on a result of the test of at least one already tested test criterion.

8. The method of claim 1 wherein the test element is at least one of: a cylinder shape; a circle shape; a cone shape; a sphere shape; a torus shape; a two-dimensional straight line; a slot; a plane; a plane of symmetry; and a rectangle shape.

9. The method of claim 1 wherein a property of the test element is at least one of: a diameter variable; a further diameter variable; a length variable; a width variable; a ratio of length to diameter; a ratio of length to width; a distance variable; an angle variable; an internal or external identifier; the membership of a test feature group; and the membership of a test feature type.

10. The method of claim 1 wherein the test as to whether there is an applicable measurement rule in the measurement rule set is carried out based on at least two different properties of the test element, with the different properties being tested sequentially.

11. The method of claim 10 wherein the property to be tested in a subsequent test step is determined based on at least one already tested property.

12. The method of claim 10 wherein the property to be tested in a subsequent test step is determined based on a result of the test of at least one already tested property.

13. The method of claim 1 wherein a test element is determined in model-based fashion.

14. The method of claim 1 wherein the measurement object is measured and the test element is determined by evaluating the measurement results.

15. The method of claim 1 wherein: the measurement object is measured in accordance with the new or altered measurement strategy and a measurement quality of the measurement is determined, at least one test element of the measurement object is determined, there is an automated test for the test element as to whether there is an applicable measurement rule in a measurement rule set of measurement rules defined in advance, the test is implemented based on the measurement quality, and the test element-specific measurement rule of the new measurement strategy is altered or the test element-specific measurement rule of the altered measurement strategy is altered again in response to this measurement rule being applicable to the test element.

16. An apparatus for determining a measurement strategy for measuring a measurement object, the apparatus comprising: a data processing device, wherein at least one test element of the measurement object is able to be determined, wherein there is an automated test for the test element by the data processing device as to whether there is an applicable measurement rule in a measurement rule set of measurement rules defined in advance, wherein an applicable measurement rule is added to a new measurement strategy or the test element-specific measurement rule of an existing measurement strategy is altered based on an applicable measurement rule, wherein the measurement rules of the measurement rule set are determined by virtue of a measurement rule and at least one test criterion in respect of the applicability thereof being set for a test element by a user or in (partly) automated fashion, and wherein the measurement rule defines at least one parameter for measuring the test element.

17. A non-transitory computer-readable medium storing instructions comprising: determining a test element of a measurement object, wherein there is an automated test for the test element as to whether there is an applicable measurement rule in a measurement rule set of measurement rules defined in advance, wherein an applicable measurement rule is added to a new measurement strategy or the test element-specific measurement rule of an existing measurement strategy is altered based on an applicable measurement rule, wherein the measurement rules of the measurement rule set are determined by virtue of a measurement rule and at least one test criterion in respect of the applicability thereof being set for a test element by a user or in (partly) automated fashion, and wherein the measurement rule defines at least one parameter for measuring the test element.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0141] The present disclosure will become more fully understood from the detailed description and the accompanying drawings.

[0142] FIG. 1 is a schematic flowchart of a method according to the principles of the present disclosure.

[0143] FIG. 2 is a schematic flowchart of a plurality of test criteria for evaluating the same property.

[0144] FIG. 3 is a schematic flowchart of testing different properties of a test element.

[0145] FIG. 4 is an example illustration of a user interface of a strategy editor module.

[0146] FIG. 5 is a schematic illustration of a measurement object.

[0147] FIG. 6 is an example illustration of a user interface of a strategy assignment module.

[0148] FIG. 7 is a schematic illustration of an apparatus according to the principles of the present disclosure.

[0149] In the drawings, reference numbers may be reused to identify similar and/or identical elements.

DETAILED DESCRIPTION

[0150] FIG. 1 shows a schematic flowchart of a method according to the invention for determining a measurement strategy for measuring a measurement object 1 (see FIG. 5).

[0151] In a test criterion definition step S0a of a definition step S0, the user or a data processing device 2 (see FIG. 7) defines, in (partly) automated fashion, a test criterion in respect of the applicability of a measurement rule for measuring a test element. Then, the measurement rule which is defined when the test criterion is satisfied is defined in a measurement rule definition step S0b, for example also by a user or in (partly) automated fashion. The sequence of test criterion definition step S0a and measurement rule definition step S0b can be repeated to define a plurality of measurement rules and test criteria assigned thereto. It is, however, also possible that the measurement rule is defined first and then the test criterion in respect of the applicability thereof is defined. As outlined before, the definition steps S0a, S0b can be carried out in a measurement object-independent build-up of the measurement rule set.

[0152] In particular, the test criterion can be defined by virtue of a property of the test element to be tested, preferably a geometric property, a type of the test and a target variable for the property to satisfy the test criterion being defined. The test criterion is satisfied when the property satisfies the criterion defined by the type of test and the target variable.

[0153] In this case, the definition step S0 can be carried out at an earlier time to implementing the method, which consists of the sequence of a first step S1, a second step S2 and a third step S3. The measurement rules defined in the definition step S0 and test criteria in respect of the applicability thereof assigned thereto are stored and form a measurement rule set of measurement rules defined in advance, with corresponding test criteria being assigned thereto. It is also possible that the measurement rule set is extended in the test step S2 as will be explained later.

[0154] In a first step S1 of the proposed method, which can also be referred to as determination step, at least one test element of a measurement object 1 (see FIG. 5) is determined.

[0155] In the determination step, the test element of the measurement object 1 can be determined in model-based fashion. This has already been explained above. In particular, a CAD model can be loaded, with test elements of the measurement object 1 being extracted from the CAD model. Corresponding methods are known to the person skilled in the art. It is also conceivable to measure the measurement object 1 and then determine test elements of the measurement object 1 on the basis of the measurement results. In this context, a resolution of this measurement can be coarser than the resolution of the measurement with the measurement strategy to be determined as proposed.

[0156] In a second step S2, which can also be referred to as test step, a test is carried out as to whether one of the measurement rules of the measurement rule set defined in the definition step S0 is applicable to the test element. To this end, at least one property of the test element, but preferably a plurality of properties thereof, can be determined, wherein a test is then carried out on the basis of the test criteria defined in the definition step S0 as to whether all test criteria assigned to a measurement rule are satisfied. By way of example, this is the case if one or more properties of the test element each correspond to a target property or lie in a predetermined target property range.

[0157] If an applicable measurement rule is identified, the latter is added to a new measurement strategy or an existing measurement strategy is altered accordingly in a third step S3, which can also be referred to as addition or change step S3.

[0158] If no applicable measurement rule is identified for a test element selected in the determination step in the measurement rule set, a measurement rule not included in the measurement rule set can be determined as the applicable measurement rule, in particular in an automated or partially automated manner. For example, a default measurement rule can be determined as an applicable measurement rule for the test element. Alternatively, an applicable measurement rule may be determined based on at least one similar measurement rule of the existing measurement rule set. Further alternatively, an applicable measurement rule may be determined based on at least one property of a measurement scenario. Further alternatively, an applicable property may be determined by evaluating existing measurement rules. This has been explained previously.

[0159] Further, the measurement rule thus determined may be added to the measurement rule set. In this case, as also explained previously, at least one criterion for its applicability can be determined, in particular also in an automated or semi-automated manner. In this case, the set of measurement rules is expanded in a (partially) automated manner.

[0160] In a fourth (optional) step S4, a coordinate measuring machine (not illustrated) can then be controlled in such a way that the measurement of the measurement object 1 is carried out in accordance with the accordingly defined measurement strategy, which may comprise one or more measurement rules.

[0161] FIG. 2 shows a schematic flowchart which represents the definition of a measurement rule.

[0162] In this case, the definition is presented for a cylindrical test element Cyl, i.e., a test element that has a cylinder shape.

[0163] What is defined in this context is that a test is carried out in a first test step PS1 as to whether the length L of the cylindrical test element is less than the diameter D of the cylindrical test element. This can be implemented in a test criterion definition step S0a of the definition step S0. Should this be the case, at least one parameter for measuring the test element is defined in accordance with the above-described measurement rule definition step S0b of the definition step S0, for example a speed of a relative movement between measurement object 1 and a sensor of the coordinate measuring machine, which can also be referred to as scanning speed, and the number of measurement points to be generated along a lateral face of the cylinder and an angle range to be measured.

[0164] What is further defined is that—if the test criterion in the first test step PS1 is not satisfied—a test is carried out in a second test step PS2 as to whether the length L is less than three times the diameter D of the cylindrical test element. This can be implemented in a test criterion definition step S0a of the corresponding definition step S0. If this test criterion is satisfied, a measurement rule is defined by defining corresponding parameters for the measurement, which may differ from the measurement rule when the test criterion in the first test step PS1 is satisfied. By way of example, a higher relative speed, a greater number of measurement points and a smaller angle range to be measured can be chosen.

[0165] What is further defined is that, if the test criterion in the second test step PS2 is not satisfied, a test is carried out in a third test step PS3 as to whether the length L is greater than or equal to three times the diameter D of the cylindrical test element. If this is the case, a corresponding measurement rule is defined by defining parameters for the measurement, wherein, for example, the scanning speed can be defined to be again higher, the number of measurement points can be defined to be yet again greater and the angle range can be defined to be yet again smaller than in the case where the criterion in the second test step PS2 is satisfied.

[0166] The definition of the test criteria for the illustrated subsequent steps PS1, PS2, PS3 and the definition of the parameters of the measurement rule in the corresponding measurement rules can be defined by a user in this case, in particular by repeatedly implementing the sequence of test criterion definition step and measurement rule definition step S0a, S0b of the definition step S0. It is also possible for both the criteria and the parameters to be defined in (partly) automated fashion.

[0167] The measurement rules defined thus are supplied to a rule generator 7, which generates a correspondingly implementable code for testing the applicability. The rule generator 7 can also generate code means for measuring the measurement object 1 using the parameters defined in the corresponding measurement rules, with these then facilitating the measurement of the measurement object 1 using the coordinate measuring machine which can be controlled in accordance with the code means generated thus.

[0168] FIG. 3 shows a further schematic flowchart of defining measurement rules and test criteria, wherein different properties of the measurement object 1 are evaluated in different test steps.

[0169] In this case, the definition is presented for a cylindrical test element Cyl, i.e., a test element that has a cylinder shape.

[0170] For a first test step PS11 for testing a first property, specifically the ratio of length L to diameter D, it is defined that a test is implemented as to whether the length L of the cylindrical test element is less than the diameter D of the cylindrical test element. If this feature is satisfied, it is defined in a first partial step S0b_1 of a measurement rule definition step S0b that there is a measurement of the cylindrical test element using two mutually different circular trajectories. Hereinafter, it is defined for a first test step PS12 for testing a further property that a test is carried out as to whether the diameter D is less than 8 mm. If this test criterion has been satisfied, further parameters for measuring the test element, for example the scanning speed, the number of measurement points and the angle range to be measured, are defined in a further partial step S0b_2 of the measurement rule definition step S0b.

[0171] There is further definition that, if the criterion tested in the first test step PS12 is not satisfied, a test is carried out in a second test step P22 of the further property as to whether the diameter D is less than 81 mm. If this criterion has been satisfied, the specified further parameters are defined in an alternative partial step S0b_2 of the measurement rule definition step S0b, wherein, however, different values are defined than when the criterion in the first test step P12 of the further property is satisfied.

[0172] There is further definition that, if this criterion tested in the second test step PS22 is not satisfied, a further test criterion is evaluated in a third test step P23 of the further property, specifically whether the diameter is greater than 250 mm. If this is satisfied, the specified further parameters are defined in an alternative partial step S0b_2 of the measurement rule definition step S0b, wherein, however, different values are defined than when the criterion in the first test step P12 of the further property is satisfied and when the criterion in the second test step P22 of the further property is satisfied.

[0173] If the test criterion in the first PS11 of the first property is not satisfied, corresponding further test steps with test criteria are defined, which, when satisfied, then lead to a measurement rule being defined at least in part and/or a definition of test steps with test criteria for testing the further properties being defined.

[0174] Consequently, this yields a tree structure, by means of which test criteria and corresponding measurement rules are defined.

[0175] FIG. 4 shows an example illustration of a user interface of a strategy editor module. Different test elements, which are characterized by geometric properties of the test element, are displayed in a test element column Sp. Thus, a circle, a cylinder Cyl, a cone, a slot and a rectangle are illustrated in this column Sp.

[0176] As a result of the graphical representation, these test elements are offered to the user for selection. The user can select a test element, for example from a suitable input device, for example a mouse.

[0177] In the example embodiment illustrated in FIG. 4, the assumption is made that a cylinder Cyl was selected as test element.

[0178] In the first selection menu AM1, the user can then select the first property to be tested in one or more test criteria, wherein, in the example embodiment illustrated in FIG. 4, a ratio of length L to diameter D of a cylindrical test element is selected in example fashion as property to be tested.

[0179] An arrow at the right edge of the selection menu AM1 symbolizes that further properties are offered for selection. In this context, however, only the properties that are test element-specific properties can be offered for selection.

[0180] In an indented input line EZ, the user can then quantify values for evaluating the test criterion, by way of which the ratio of length L to diameter D are evaluated. Thus, what is illustrated is that, by inputting corresponding values in the input line EZ, a test is carried out as to whether the ratio of length L to diameter D is greater than or equal to 0 and less than 1.0. Illustrated further is a further input line for quantifying a further test criterion for testing the first property, wherein input of corresponding values defines that a test is carried out as to whether the ratio of length L to diameter D is greater than or equal to 1.0 and less than 3.0.

[0181] Further, a further property to be tested can be defined by the user, in particular by means of a second selection menu AM2. In the example embodiment illustrated in FIG. 4, this further property is the diameter D of the cylindrical test element. In accordance with the explanations given above, inputting values into one or more input lines EZ can then define one or more test criteria which require the diameter D for evaluation purposes. In the example embodiment illustrated in FIG. 4, three such test criteria are defined in example fashion, which test criteria can be tested in successive test steps. For the purposes of evaluating a first test criterion, it is defined that there is an evaluation as to whether the diameter is greater than or equal to 0 and less than 8.0 mm. For a second test criterion, it is defined that there is an evaluation as to whether the diameter is greater than or equal to 8.0 mm and less than 81.0 mm. For a third test criterion, it is defined that there is a test as to whether the diameter D is greater than or equal to 81.0 mm and less than 250 mm.

[0182] Further illustrated are activation boxes AB in an input line EZ, which activation boxes can be activated by a user, for example by means of a suitable input device, in order to activate the use of the test criterion defined by the values of this input line EZ when testing for applicable measurement rules.

[0183] By way of a definition box FB in an input line EZ, the user can call a window for defining the parameters for measuring the test element which are defined when the corresponding test criterion is satisfied. If the user actuates such a definition box FB, for example by actuating a corresponding input device, a new window with the parameters to be defined can open. In this case, the parameters can be test element-specific parameters. It is also conceivable for the parameters to have a specified standard value in the case of a first call.

[0184] Further illustrated is a deletion box LB in an input line EZ, wherein the user can delete the test criterion defined by the parameters entered in this line when actuating this deletion box LB.

[0185] The user interface illustrated in FIG. 4 can be generated and displayed by a so-called strategy editor module, wherein this module is implemented, for example, by a data processing device 2 (see FIG. 7).

[0186] FIG. 5 shows an example illustration of a measurement object 1. The latter consists of a first cylinder Cyl1 and a second cylinder Cy12, which have different diameters and different lengths. These cylinders Cyl1, Cy12 form test elements of the measurement object 1.

[0187] FIG. 6 shows an example illustration of a user interface of a strategy assignment module. Using this module, the functionality of which can likewise be provided by means of a data processing device 2 (see FIG. 7), it is possible, for example, to determine the test elements Cyl1, Cy12, for example in model-based fashion. This has already been explained above. To this end, the strategy assignment module, for example, can analyse a CAD model of the measurement object 1 and identify the corresponding test elements Cyl1, Cy12.

[0188] FIG. 6 illustrates that the different identified test elements of a measurement object 1 (see FIG. 5) are illustrated in a column Sp. In the example embodiment illustrated in FIG. 6, the first cylinder Cy11 and the second cylinder Cy12 are illustrated in example fashion.

[0189] By way of the strategy assignment module, it is then possible to test whether an applicable measurement rule exists for each of the test elements Cyl1, Cy12 in a measurement rule set of measurement rules defined in advance.

[0190] In a further column, which can also be referred to as control column RSp, the applicable measurement rules of the measurement rule set of measurement rules defined in advance are represented in line form, which applicable measurement rules are applicable to the first test element, specifically the first cylinder Cyl1, and to the further cylinder Cy12. Thus, illustrated in a first line Z as a first test element is the first cylinder Cyl1 and the test criterion, which is assigned to the measurement rule identified as applicable. Illustrated in a further line Z as a further test element is the second cylinder Cy12 and the test criterion, which is assigned to the measurement rule identified as applicable.

[0191] It is evident that the measurement rule that arises if the test element has a cylinder shape Cyl and the ratio of length L to diameter D of the cylinder shape Cyl is greater than or equal to 0.0 and less than 1.0 is assigned to the first cylinder Cyl1. The corresponding measurement rule was defined, for example, by the user interface illustrated in FIG. 4, in particular by actuating the definition box FB and inputting the corresponding parameters.

[0192] Accordingly, the measurement rule that is applicable if the test element has a cylinder shape Cyl and the ratio of length L to diameter D is between 1.0 and 3.0 is assigned to the second cylinder Cy12.

[0193] Once again, activation boxes AB are illustrated, by the activation of which the user defines that the measurement rule classified as applicable is added to the measurement strategy.

[0194] Illustrated further is an overwrite function, which, if activated, for example by a user, leads to the measurement strategy selected in a selection menu AM for different existing measurement strategies being overwritten when an assignment button ZS is actuated. Illustrated further is a creation function, which, if activated, for example by a user, leads to the file name entered in an input field EF being used to store the newly created measurement strategy when the assignment button ZS is actuated.

[0195] FIG. 7 shows a schematic block diagram of an apparatus for determining a measurement strategy for measuring a measurement object 1 (see FIG. 5). The apparatus 1 comprises a data processing device 2 and an input device 4. The apparatus 1 likewise comprises a display device 5, in particular for displaying the interfaces illustrated in FIG. 4 and FIG. 6.

[0196] By means of the input device 4, a user can input test criteria or parameters required for the evaluation of test criteria and measurement rules or parameters of a measurement rule. By means of the input device 4, the user can also manage already created measurement rules and test criteria, e.g., alter these or add new measurement rules and test criteria or delete existing measurement rules and test criteria.

[0197] It is illustrated that the apparatus 1 comprises a storage device 6, in which the measurement rule set of measurement rules defined in advance and the test criteria assigned thereto are stored in order then to be able to retrieve these for the test of applicability.

[0198] The term non-transitory computer-readable medium does not encompass transitory electrical or electromagnetic signals propagating through a medium (such as on a carrier wave). Non-limiting examples of a non-transitory computer-readable medium are nonvolatile memory circuits (such as a flash memory circuit, an erasable programmable read-only memory circuit, or a mask read-only memory circuit), volatile memory circuits (such as a static random access memory circuit or a dynamic random access memory circuit), magnetic storage media (such as an analog or digital magnetic tape or a hard disk drive), and optical storage media (such as a CD, a DVD, or a Blu-ray Disc). The phrase at least one of A, B, and C should be construed to mean a logical (A OR B OR C), using a non-exclusive logical OR, and should not be construed to mean “at least one of A, at least one of B, and at least one of C.”

LIST OF REFERENCE SIGNS

[0199] 1 Measurement object [0200] 2 Data processing device [0201] 3 Apparatus [0202] 4 Input device [0203] 5 Display device [0204] 6 Storage device [0205] 7 Rule generator [0206] S0 Definition step [0207] S0a Test criterion definition step [0208] S0b Measurement rule definition step [0209] S0b_1 First partial step of the measurement rule definition step [0210] S0b_2 Further partial step of the measurement rule definition step [0211] S1 Determination step [0212] S2 Test step [0213] S3 Addition/change step [0214] S4 Measurement step [0215] Cyl Cylinder, cylinder shape [0216] P51, PS2, PS3 Test step [0217] PS11 Test step [0218] PS12, PS22, PS32 Test step [0219] L Length [0220] D Diameter [0221] Sp Column [0222] AM, AM1 Selection menu [0223] AB Activation box [0224] FB Definition box [0225] LB Deletion box [0226] AM2 Selection menu [0227] ZS Assignment button [0228] EF Input field [0229] RSp Control column [0230] Cyl1 First cylinder [0231] Cy12 Further cylinder [0232] EZ Input line [0233] Z Line