METHOD FOR MEASURING A WORKPIECE TO BE MEASURED USING A COORDINATE MEASURING DEVICE

Description

[0001] The invention relates to a method for measuring a workpiece using a coordinate measuring machine. A workpiece is understood to include, in particular, an arrangement of interconnected parts. The invention specifically relates to the automatic creation of a measurement sequence for measuring a workpiece. Automatic creation does not preclude the possibility that parts of the measurement sequence may be optionally checked and / or modified by a person.

[0002] When measuring a workpiece, its coordinates are determined using at least one coordinate measuring machine. Specific embodiments of the method according to the invention therefore include the process of measuring the workpiece and determining the coordinates of the workpiece to be measured, or of a workpiece of the same type, from measurement data.

[0003] The term coordinate measuring machine (CMM) encompasses all types of devices used to determine the coordinates of workpieces. One class of CMMs determines surface coordinates, meaning they measure the coordinates of points on the workpiece's surface. Another class, either alternatively or additionally, can determine internal coordinates within workpieces. These include CMMs that utilize invasive radiation penetrating the workpiece material, specifically measuring the intensity of the radiation passing through the workpiece. Typically, the workpiece is irradiated from various directions, and the results are used to perform a computer-aided reconstruction of the scanned workpiece. Such methods are also known as computed tomography (CT).The term coordinate measuring machine (CMM) encompasses both classic CMMs, such as portal-type or gantry-type machines, and in particular CMMs with a movable bridge on which a quill with a sensor movable relative to the bridge is mounted, as well as articulated arm machines and machines with a hexapod mechanism. It also includes machines in which at least one sensor is fixed with respect to at least one degree of freedom of the relative movement between the sensor and the workpiece, and in which the workpiece to be measured is movable relative to the at least one sensor, as in a machine with a movable measuring table. Furthermore, the term CMM covers machines that, while not primarily designed as CMMs, are configured to operate like a CMM.In particular, these machines have at least one measuring sensor used to determine the coordinates. Examples include robots, such as articulated-arm robots, on which a sensor for detecting the workpiece surface (e.g., a fringe projection sensor) is attached instead of or in addition to a tool, or machine tools on which a measuring sensor (e.g., a tactile sensor) is attached instead of or in addition to a machining tool. Hexapod mechanisms are also known, on which a sensor for detecting the workpiece surface (e.g., a tactile sensor) is attached instead of a machining tool.

[0004] Person-operated (e.g., handheld) sensors for detecting a workpiece are also known, where at least one sensor is optionally mounted on a movable mechanism. In this case, there is no motor drive to generate the sensor's movement. Instead, the movement is effected by a person. Both scanning and scanning of the object are possible, with the sensor being positioned at a fixed angle. The triangulation principle is frequently used in person-operated sensors: for example, a known pattern is projected onto the object, and at least one image of the object's surface is captured from a different angle. Laser radiation can also be used instead of a pattern projection when applying the triangulation principle.In particular, the location where the reflected laser radiation is received contains information about the surface coordinates of the object being measured. However, devices with a person-operated sensor are also known, which have at least one motor to assist in the movement and / or positioning of the sensor.

[0005] The invention is not limited with regard to the types of sensors used by a coordinate measuring machine to determine the coordinates. Tactile sensors have already been mentioned as an example; these can be, for instance, of the switching or measuring type. In particular, the tactile sensors can be passive or active. Active sensors can be configured to generate a probing force with which a tactile probe contacts the surface of a workpiece to be measured. Optical sensors are frequently used alternatively or additionally, e.g., a projection sensor, in particular a fringe projection sensor, a laser triangulation sensor, a line scan camera, a camera for capturing two-dimensional images, a camera for capturing three-dimensional images, an arrangement with at least two cameras, or a confocal chromatic sensor.Furthermore, there are, for example, capacitive sensors and inductive sensors.

[0006] The term coordinate measuring machine therefore also includes 3D scanners. As mentioned above, but not limited to handheld sensors, triangulation-based systems such as laser scanners and projection sensors are particularly advantageous because they can generate many measurement points with their 3D coordinates in a short time. Projection sensors project an area pattern, e.g., a striped pattern, onto the object being measured and capture images of the object along with the projected pattern using at least one image capture unit (camera). By analyzing the images, the 3D coordinates of surface points on the object can be determined. To completely capture an object or its surface, a single measurement position is often insufficient, so the relative position of the 3D scanner to the object is usually changed multiple times.This positioning can be done manually (handheld), or semi-automatically or automatically, for example by guiding the 3D scanner with a robot. The change in position can also be achieved by moving the object relative to the 3D scanner, for example using a rotary table.

[0007] Identical workpieces can be measured and inspected according to the same inspection plan. To prepare for the measurement and evaluate the measurement data obtained from the workpiece measurement, it is known to create an inspection plan. This plan defines the workpiece's inspection characteristics to be determined from the measurement data and includes them as part of the inspection plan. A measurement procedure can then be generated from these inspection characteristics. This measurement procedure specifies which measuring points of a workpiece are to be measured by a coordinate measuring machine in order to determine a single inspection characteristic, multiple inspection characteristics, or all inspection characteristics to be determined. The method therefore also includes configurations in which a measurement procedure is generated for at least one inspection characteristic of a workpiece, specifying the measuring points of the workpiece to be measured.As in the case of a measurement plan, the measurement instruction may already contain all the information necessary for controlling a measuring sensor of a specific coordinate measuring machine type, or it may specify measuring points that can be measured using at least one of different types of coordinate measuring machines and / or different types of measuring sensors.

[0008] A test plan defines, in particular, a test process by which the quality of a workpiece to be measured can be determined. Such a test plan can be established, for example, based on certain general standards or manufacturer or customer specifications.

[0009] The inspection plan or a measurement plan derived therefrom may contain program instructions and / or an algorithm that causes a coordinate measuring machine and at least one measuring computer to carry out the inspection process in accordance with the inspection plan and, in particular, to determine the inspection characteristics with respect to the measured workpiece, i.e., usually to determine at least one value of the inspection characteristic.

[0010] In general, the inspection plan and / or measurement plan can be a file or a computer program that is readable and / or executable by a control unit, where the control unit is, in particular, the control unit of a coordinate measuring machine and / or at least a measuring computer that evaluates the measurement data generated by the coordinate measuring machine in order to determine the inspection characteristics. However, the inspection plan can also simply be a list of inspection characteristics or an extended list of inspection characteristics. In the simplest case, the list may contain a single inspection characteristic. In any case, however, an inspection plan is a set of instructions relating to the measurement of a workpiece to be measured and relating to the evaluation of the measurement data obtained during the measurement, at least by determining one inspection characteristic based on the measurement data.

[0011] In general usage, inspection characteristics are quality characteristics of a process or product. In coordinate measuring technology, inspection characteristics are based on the direct and indirect measurement results from the measurement of workpieces. Typically, the coordinates of the respective workpiece are first determined by measuring it using one or more coordinate measuring machines, and then at least one value for a predefined inspection characteristic is determined. As a rule, the coordinates of more than one measuring point or at least one area of ​​the workpiece are required to determine the inspection characteristic. Examples of inspection characteristics include straightness, flatness, roundness, cylindricity, line profile, surface profile, position, perpendicularity, inclination, parallelism, symmetry, coaxiality, concentricity, radial runout, axial runout, total radial runout, and total axial runout.Numerous other inspection characteristics are known to those skilled in the art, such as gap and transition dimensions. To later verify whether a workpiece meets expectations according to the respective inspection characteristic, a permissible tolerance is generally defined. Even when inspection plans are used repeatedly, the permissible tolerance can vary in individual cases. Furthermore, the procedures for determining an inspection characteristic by evaluating coordinate measurement data of a workpiece can vary. Therefore, specifications regarding the procedure can optionally be included as additional information for the respective inspection characteristic. The foregoing applies in particular to embodiments of the invention described below.

[0012] Selecting and / or defining the test characteristics for a test plan involves considerable effort, especially when a complete or nearly complete list of test characteristics is to be compiled for a specific workpiece type and the verification of its technical specifications. Generally, and also with regard to the present invention, the technical specification may, for example, be in the form of a CAD (Computer-Aided Design) model with PMI (Product Manufacturing Information). However, in many cases, a complete list of test characteristics cannot be derived from such a technical specification. Rather, additional experience and knowledge are required to complete the list.

[0013] WO 2016 / 150517 A1 already proposed supporting the operator in this process. A database is provided containing a large number of predefined measuring elements and a large number of typical inspection characteristics for these predefined measuring elements. Each typical inspection characteristic represents a defined dimensional property of at least one predefined measuring element. Furthermore, a graphic representation of the object being measured is provided, showing at least one initial geometric element. The operator can select the initial geometric element based on this graphic representation. Subsequently, suitable inspection characteristics for the selected initial geometric element are displayed. The appropriate inspection characteristics are determined from the large number of typical inspection characteristics in the database by assigning the selected initial geometric element to a predefined measuring element of the same type.The operator can select a suitable displayed test feature. Depending on the selected test feature, a defined measurement sequence is created. In a specific embodiment, the operator is offered suitable linking elements for the automatic creation of a defined measurement sequence as soon as at least two geometric elements have been selected in the graphical representation of the object being measured. Preferably, the display of suitable test features and the display of suitable linking elements occur simultaneously, so that the operator can create a complex measurement sequence by selecting test features and linking elements in a single display.

[0014] EP 3 794 310 B1 describes the generation of a test plan for the inspection of a measured object, wherein a data set representing the measured object is provided, wherein a reference structure is defined based on data, wherein at least one reference structure-specific test characteristic is assigned to the reference structure, wherein the data set representing the measured object is checked based on data to see if structures similar or identical to the reference structure exist, wherein the reference structure-specific test characteristic is assigned to each similar or identical structure as a structure-specific test characteristic, and wherein the test plan includes the structure-specific test characteristics determined in this way.

[0015] EP 3 835 900 A1 discloses a method for measuring workpieces, wherein each of the workpieces has several structural features that are present in the same way in the other workpieces, and which are test features to be measured. A test plan can specify optimized traverse movements of a measuring sensor between individual measuring points so that the measurement time can be kept to a minimum.

[0016] EP 3 882 568 A1 proposes a computer-implemented method for automatically creating at least one test plan for measuring at least one object.

[0017] It is an object of the present invention to facilitate the determination of at least one test characteristic for inclusion in a test plan.

[0018] The attached patent claims define the scope of protection.

[0019] It is proposed that data records be stored in advance in a database, containing data about at least two geometric elements of a workpiece and about at least one geometric relationship between the at least two geometric elements.

[0020] According to the invention, the geometric relationship is a dimensional relationship, i.e., a relationship defined with respect to one or more dimensions of a system of quantities. Examples of dimensions are lengths (e.g., distances, dimensions, diameters), areas (e.g., of surface regions), volumes (e.g., partial volumes of workpieces), angles (e.g., angles enclosed by two edges or two planes, or angles as a measure of the size of circular segments), and radii of curvature (e.g., of edges). It is generally possible to specify a value for the dimension or for each individual dimension. Therefore, if a real workpiece is available, or if sufficient planning data (e.g., CAD data used as a basis for manufacturing) of a workpiece is available, the geometric relationship can be defined.For a given workpiece type, a value for the respective dimension must be determined, particularly using at least one coordinate measuring machine that determines the coordinates of measuring points on the workpiece, or by evaluating the planning data. An example of this is the distance between two geometric elements, for instance, two parallel edges or the lines that represent these parallel edges. The dimensional relationship of these parallel lines can define that the distance must have a specific value. However, the dimensional relationship need not always refer to the values ​​of dimensions that must be determined to ascertain the presence of the geometric elements in the data set. Rather, in other cases, the dimensional relationship can define, for example, the ratio (e.g., as a quotient or otherwise) of a dimension of one geometric element to a dimension of the other geometric element.A simple example is the ratio of the lengths of one geometric element to the length of another. Referring to the example of parallel lines, the ratio of the distance between the two lines to the length of at least one of the lines can also be defined as a dimensional relationship. However, it should be emphasized that a dataset can also contain data on more than two geometric elements (i.e., the geometric elements are defined at least in such a way that they can be determined from measurement data of the workpiece to be measured or from the workpiece design data). Therefore, the dataset can also contain one or more dimensional relationships relating to more than two geometric elements.

[0021] Furthermore, the data set contains at least one inspection characteristic assigned to at least two geometric elements, which can be verified for the workpiece with respect to these at least two geometric elements. In many cases, even when only two geometric elements are present for which the data set contains data, the data set contains more than one assigned inspection characteristic.

[0022] Such a data set makes it possible to determine whether the workpiece to be measured possesses at least two geometric elements and at least one geometric relationship specified in the data set. If this is determined, then the assigned inspection characteristic, or at least one of the assigned inspection characteristics, can be automatically included in an inspection plan for testing the workpiece.

[0023] The invention thus makes it possible to objectively and automatically determine, based on geometrically dimensional criteria, whether predefined test characteristics relating to the geometry of any workpiece should be included in the test plan of a workpiece to be measured. If the geometry of the workpiece to be measured corresponds to the geometry defined in the respective data set, then the test characteristic, or at least one of the assigned test characteristics (and preferably all test characteristics assigned by the data set), is included in the test plan. Thus, the results of the previous creation of test characteristic lists for similar workpieces can be automatically used for the test plan of the workpiece to be measured. This also applies in particular to the combination of several test characteristics.If such a combination has already been defined for a similar workpiece and at least a corresponding data set has been created, then, if there is sufficient agreement or similarity between the workpiece to be measured, such a combination of test characteristics can also be included in the test plan.

[0024] Identifying a test characteristic or combination of test characteristics from data records stored in a database also allows for the identification of additional information relevant to the workpiece measurement process, provided this additional information is also stored in the database or a reference to it is stored there. In particular, the data record can therefore contain such additional information and / or a reference to it. The reference is designed to allow access to the additional information. Specifically, this additional information can therefore be included in the test plan and / or a corresponding measurement plan for measuring the workpiece to be measured or for measuring a workpiece of the same type. This inclusion can occur depending on the determination result described below.

[0025] This additional information may include, in particular, information relating to the determination of the test characteristic, for example, the specification of the evaluation method (e.g., evaluation via Gaussian element or with modifier, e.g., with projected tolerance zone), and / or information relating to auxiliary constructs indirectly required for the test characteristic (e.g., line of symmetry, intersection point, ...).

[0026] In particular, the following is proposed: A method according to claim 1 for measuring a workpiece to be measured using a coordinate measuring machine, wherein, among other things, a database is accessed in which a plurality of data records are stored, each containing data about: a) at least two geometric elements that a workpiece can have, b) at least one geometric relationship between the at least two geometric elements, wherein the geometric relationship is a dimensional relationship that thus allows it to be determined, for a workpiece to be measured, by determining and evaluating the coordinates of the at least two geometric elements, whether the geometric relationship exists, c) at least one test characteristic assigned to the at least two geometric elements, which is verifiable with respect to the at least two geometric elements for a workpiece to be tested, workpiece coordinates are determined for a workpiece to be measured by evaluating measurement data of the workpiece to be measured and / or planning data of the workpiece to be measured, and the workpiece coordinates are used to determine the workpiece coordinates.whether the workpiece to be measured exhibits at least two geometric elements and at least one geometric relationship of at least one of the plurality of data sets, and a corresponding determination result is generated, and depending on the determination result with regard to the respective data set, at least one assigned test characteristic or at least one assigned test characteristic is included in a test plan for measuring the workpiece to be measured or for measuring a workpiece of the same type, or is confirmed as part of the test plan.

[0027] The nature of the geometric relationship has already been discussed above. It is a dimensional geometric relationship, which means that, for a workpiece to be measured, it is possible to determine whether the geometric relationship exists by determining and evaluating the coordinates of at least two geometric elements. However, the ability to determine whether the geometric relationship exists is not a sufficient condition for it to be a dimensional relationship. For example, a non-dimensional geometric relationship between two parallel lines, each representing an edge of a workpiece, can consist of their parallelism. Many types of workpieces fulfill this condition; there simply need to be two parallel edges. However, if the geometric relationship additionally defines that the distance between the parallel lines has a defined value (i.e., a value of the dimension length or distance), then it is a non-dimensional geometric relationship.If a geometric element must have a certain distance (distance), and / or if it is additionally defined that the length of the distance is in a defined ratio to another dimension of at least one of the geometric elements, then this is a dimensional geometric relationship and allows for the more targeted identification of groups of geometric elements. The test characteristics corresponding to these specifically identified groups, which were already useful in the inspection of workpieces, can therefore be determined more precisely with respect to the workpiece to be measured than without considering the dimensionality of the relationship.

[0028] As stated above, the data set refers to a workpiece to be measured. Particularly when, as in series production, multiple workpieces of the same type are manufactured, the data set can also refer to a single workpiece of the same type. In this case, it can also be said that the data set refers to the workpiece to be measured. Furthermore, the workpiece coordinates for determining whether the workpiece to be measured exhibits at least two geometric elements and at least one geometric relationship from at least one of the multiple data sets can be obtained from a workpiece of the same type, and it can still be correctly stated that the workpiece coordinates are also valid for the workpiece to be measured. In other words, the workpiece to be measured can be a specific instance or any instance of a type.Within the scope of this determination, it is irrelevant in most cases whether there are minor deviations between identical workpieces and / or between one of the identical workpieces and the planning data. For this reason, it is preferred that a tolerance be allowed when determining whether the workpiece to be measured possesses the at least two geometric elements and the at least one geometric relationship of at least one of the multiple data sets. This means that, in particular, it is also determined that the workpiece to be measured possesses the at least two geometric elements and the at least one geometric relationship of the data set if the specified maximum tolerance is not exceeded. The tolerance can relate to all dimensional and positional data as well as to information used to determine the geometric elements and the geometric relationship.

[0029] Conversely, the tolerance in a given case need not apply to all of these specifications and pieces of information. Rather, a tolerance may be permitted only for one of the specifications and / or for one of the pieces of information used to determine the geometric elements and their geometric relationships. A tolerance takes various circumstances into account, such as the fact that workpiece coordinates cannot be measured exactly and that values ​​(measured values ​​and planning data) cannot be processed by computers without errors (e.g., rounding errors). Furthermore, a tolerance regarding the geometric relationship of the geometric elements can enable the determination of similar data sets. A corresponding example will be described later using the attached figures.

[0030] The aforementioned finding can be considered positive, in particular, if it means that the workpiece to be measured exhibits at least two geometric elements and at least one geometric relationship (also referred to as the workpiece to be measured corresponding to the data set) or is likely to do so according to a predefined assessment method. In the case of a positive finding, at least one assigned test characteristic, or at least one of the assigned test characteristics, can be included in the test plan for the workpiece to be measured or confirmed as part of the test plan. The procedure of conducting an assessment during the finding process and determining the probability of the workpiece to be measured corresponding to the data set represents a variation of the tolerance for deviations mentioned above.In particular, the probability can be determined by calculating, using statistical methods, the deviation from the at least two geometric elements defined in the dataset for a number of measurement points or points of the workpiece to be measured derived from the planning data, especially for a defined number of such points, taking into account the at least one geometric relationship. For example, the square root of the sum of the squared deviations of the points can be used as a measure of probability. Preferably, the measure of probability is normalized. A threshold probability can be specified for the normalized measure. If the probability obtained for a specific workpiece to be measured is above the threshold probability, the result is positive.

[0031] According to the invention, each data set defines at least two geometric elements that are dimensionally related to each other. To determine whether the geometric elements defined in a specific data set are present in a workpiece to be measured, the geometric elements defined in the data set can be individually examined to see if they are present in the workpiece. If it is found that only one of the geometric elements is present in the workpiece, or if, in the case of more than two geometric elements defined in the data set, not all of these geometric elements are present in the workpiece, the data set cannot be used to generate or verify a test plan.If, on the other hand, all geometric elements defined in the data set are present in the workpiece to be measured, it can be determined whether the dimensional geometric relationship defined in the data set also exists for the existing geometric elements or not.

[0032] More generally, in a design of the procedure, when determining whether the workpiece to be measured has at least two geometric elements and at least one geometric relationship of at least one of the plurality of data sets, it can first be determined with respect to one of the data sets whether the workpiece to be measured has all geometric elements for which the geometric relationship of the geometric elements in relation to each other is defined in the data set, and, if this is the case, it is then determined whether the geometric relationship exists for the geometric elements of the workpiece to be measured.

[0033] In particular, with regard to the same geometric elements of the workpiece to be measured, a plurality of data records stored in the database can be identified. Each of these records defines data set geometry elements that correspond to the same plurality of geometric elements of the workpiece to be measured and also defines a geometric relationship between these data set geometry elements. However, it frequently occurs that the correspondence between the geometric elements of the data set and those of the workpiece to be measured is not exact, and / or that the geometric relationship defined in the respective data set does not correspond exactly to the geometric elements of the workpiece to be measured. It is therefore proposed to determine a measure of the correspondence between the geometric elements and the geometric relationship for each of the identified data sets.

[0034] This makes it possible to mark identified data sets as non-matching or less consistent than at least one other identified data set and optionally to exclude them from the set of identified data sets. In particular, the data set with the highest degree of consistency can be selected, and at least one associated inspection characteristic or at least one of the associated inspection characteristics from this selected data set can be included in the inspection plan for measuring the workpiece to be measured or for measuring a workpiece of the same type, or confirmed as part of the inspection plan.

[0035] According to the attached claims, a plurality of data records stored in the database are identified, each defining data record geometry elements that correspond to the same plurality of geometric elements of the workpiece to be measured, and furthermore defining the geometric relationship for each of these data record geometry elements, wherein for each of the plurality of identified data records a measure of correspondence between the geometric elements and the geometric relationship is determined, and wherein, based on the measure of correspondence, at least one of the plurality of identified data records is determined to be non-corresponding or less corresponding than at least one other of the plurality of identified data records. The measure can, for example, be a measure of the aforementioned probability of correspondence between the workpiece to be measured and the data record.

[0036] The respective assigned inspection characteristic can be verified with respect to the at least two geometric elements of a workpiece to be inspected, as described above. Determining the inspection characteristic yields at least one inspection characteristic value if the data basis is sufficient. Preferably, the data set contains at least one inspection characteristic that depends on the at least two geometric elements and / or their relationship to each other. Such an inspection characteristic is therefore not one that can be determined by evaluating the coordinates of only one of the geometric elements. However, it is not excluded, and in many cases is advantageous, that the data set also contains at least one inspection characteristic that can be determined by evaluating the coordinates of only one of the geometric elements. For example, in the case of two parallel edges as the two geometric elements, the inspection characteristic "straightness" can be assigned to each of the geometric elements.Furthermore, the data set also includes, for example, the test characteristic "parallelism of the parallel edges" as a test characteristic, the determinability of which depends on the relationship of the geometric elements to each other, i.e., on the availability of the coordinates of both geometric elements.

[0037] As mentioned above, the procedure can be used not only to transfer at least one inspection characteristic from the data set into an inspection plan if the workpiece to be measured matches the data set, but also to confirm an inspection characteristic already present in an inspection plan or to confirm that an inspection characteristic under consideration for inclusion in the inspection plan is indeed being included. For example, the inspection characteristics of an existing inspection plan for a similar workpiece can be checked and, if necessary, confirmed in this way. If an inspection characteristic is not confirmed, it can be removed from the inspection plan.

[0038] The invention relates in particular to the automatic determination of workpiece coordinates, the automatic execution of the determination whether the workpiece to be measured possesses the at least two geometric elements and the at least one geometric relationship of at least one of the plurality of data sets, and the automatic recording and / or confirmation of at least one test feature of the at least one of the plurality of data sets in / for the test plan. If, in the case of determining the workpiece coordinates, measurement data of the workpiece to be measured are evaluated, the measurement of the workpiece can also be a step of the method. The evaluation of the measurement data with regard to the determination of the workpiece coordinates consists in any case at least in determining the workpiece coordinates required for the determination to be carried out.This can be limited to a selection of measurement points and / or include further evaluation steps, such as determining the coordinates for a selection of measurement points or for all measurement points from the raw measurement data of a coordinate measuring machine.

[0039] More generally, the workpiece to be measured can therefore be measured using at least one coordinate measuring machine and the measurement data can be generated to determine the workpiece coordinates.

[0040] Furthermore, alternatively or additionally, as part of the procedure, the workpiece to be measured or a workpiece of the same type can be measured according to the test plan using at least one coordinate measuring machine and / or a value of the test characteristic included in the test plan or confirmed as part of the test plan can be determined.

[0041] As mentioned, the workpiece coordinates are used to determine whether the workpiece to be measured has at least two geometric elements and at least one geometric relationship of at least one of the majority of data sets.Depending on the type of geometric element and / or the procedure, the presence (or absence) of the geometric element can be determined by evaluating the workpiece coordinates, in particular based on its geometric position (for example, position in a coordinate system of the workpiece), orientation (for example, orientation in a coordinate system of the workpiece), type (for example, plane, edge, hole), shape (for example, straight, curved, angled, circular, elliptical), size (characterized by at least one dimension) and / or relationship to other geometric elements of the workpiece (for example, edge parallel to another edge, hole as part of an arrangement with several holes, flat surface area angled relative to another flat surface area).

[0042] When evaluating planning data for the workpiece to be measured, the workpiece coordinates are used to determine whether the workpiece possesses the respective geometric element. As with the actual measurement of a workpiece, the workpiece coordinates can be the coordinates of points, i.e., they correspond to measurement points. However, depending on the data format, planning data may also evaluate geometric information other than at least some coordinates. For example, planning data is known in formats that use vectors, and thus directions and / or lengths of geometric elements, to describe the geometry of the workpiece to be measured.Depending on the type of geometric element to be determined, lengths and / or directions can be evaluated, for example, compared with corresponding lengths and / or directions of the geometric element being determined, optionally taking into account its position in the coordinate system of the workpiece or another coordinate system. Furthermore, formats are known that describe workpiece surfaces using meshes. The Triangulated Irregular Network (TIN), for example, is widely used. Information about the TIN can be stored as the triangular faces and / or as the nodes at the vertices of the triangular faces.

[0043] The database can be created once. Alternatively, it can be repeatedly supplemented with additional data records, for example, those derived from existing inspection plans. This increases the likelihood that at least one suitable data record will be available when creating an inspection plan for a workpiece.

[0044] The data records in the database can be stored in the same data format as the information about the workpiece to be measured, which is based on the workpiece coordinates, or they can be stored in a different format. Therefore, when determining whether the workpiece to be measured has a geometric element defined by the respective data record, it may be necessary to convert one data format, at least partially, into the other, or to convert both data formats to obtain comparable data. However, it is not essential to achieve exactly identical data formats, nor is it necessary to completely convert the data in the different formats into a common one. Rather, whether and to what extent at least one of the data formats needs to be modified depends on the type of geometric element and the procedure used to determine its nature.For example, a straight line of known length and position in the workpiece coordinate system, corresponding to an edge of the workpiece, can be easily compared with a multitude of points defined by the workpiece coordinates to be evaluated. For instance, a straight line can be constructed through a plurality of these points using least squares, and it can then be checked whether, or to what extent, this straight line matches the line defined in the dataset in terms of length and position. The dataset, or any other method, may define the permissible deviation of the two lines for the finding to still be considered positive, meaning the geometric element is present in the measured workpiece. With respect to the straight line, for example, a maximum deviation in the direction and a maximum deviation in the length of the lines may be defined.To avoid misunderstandings, it should be noted that the workpiece coordinates do not necessarily have to be specified in the workpiece coordinate system, although this is possible.

[0045] According to the invention, a plurality of data records are stored in the database, and the system determines from the workpiece coordinates which geometric elements from different data records correspond to geometric elements of the workpiece to be measured. For example, this can be determined for each type of geometric element, such as an edge or line, a surface area or flat surface, or a circular bore or circle, etc. For each geometric element of the workpiece to be measured that could be relevant for inspection, the stored data records can be searched for matching geometric elements, or conversely, it can be determined whether the workpiece to be measured possesses a geometric element from the data records.

[0046] The procedure may, in particular, be at least partially computer-implemented. Specifically, the computer-implemented steps mentioned above—determining the workpiece coordinates, performing the verification and recording and / or confirmation of at least one inspection characteristic of at least one of the multiple data records in / for the inspection plan—are the automatically implemented steps. Furthermore, the steps described here for measuring the workpiece to be measured or a workpiece of the same type can be controlled by computer. However, the respective measurement is always performed using at least one coordinate measuring machine. This includes automatically operated coordinate measuring machines as well as coordinate measuring machines with handheld sensors.

[0047] The scope of the invention therefore also includes a computer program comprising instructions that, when executed by a computer or an arrangement of computers, cause it(s) to execute the method in a manner or configuration described in this description. Furthermore, the invention includes a computer-readable medium comprising instructions that, when executed by a computer or an arrangement of computers, cause it(s) to execute the method in a manner or configuration described in this description.

[0048] Therefore, in particular, the apparatus for carrying out the method described below can include a computer program which performs the associated method steps if the computer program is executed on a computer or an arrangement of computers.

[0049] Those parts of the device that, as mentioned above, execute computer-implemented process steps can, for example, consist of a single computer or a computer network, or incorporate the computer or computer network. The computer, or at least one of the computers, can, in terms of its operating principle, be an analog computer, a digital computer, and / or a hybrid computer. In terms of its size and design, it can be a smartphone, a personal digital assistant (PDA), a tablet computer, an embedded system (e.g., a smartphone), or a smartphone.The computer in question can be a single- or multi-board computer (e.g., embedded in the control computer of a coordinate measuring machine), a personal computer (PC), a desktop computer, a workstation, a network-connected host computer or server, a thin client computer, a netbook, a notebook, a laptop, a mainframe computer, or a supercomputer. Some of these types can also be implemented by a single computer, such as a multi-board PC. Furthermore, the computer, or at least one of the computers, can have one or more central processing units (CPUs) and / or one or more processing cores per CPU. Graphics cards or other dedicated cards with processing units that are part of a computer can also be the means of carrying out the procedure, either alone or in combination with other computers or processing units.

[0050] Furthermore, the scope of the invention includes a computer program comprising instructions which, when the program is executed by a computer or an arrangement of computers, cause it / them to execute the computer-implemented parts of the method, in particular in one of the described embodiments.

[0051] Furthermore, it should be noted that although the computer or computers are preferably prompted to execute the method by a computer program, the means for executing the method may at least also include a hardware-implemented, preferably programmable arrangement (for example, an arrangement of logic gates), such as an ASIC (Application-Specific Integrated Circuit), a PLD (Programmable Logic Device), or an FPGA (Field Programmable Gate Array).

[0052] Furthermore, the invention includes an arrangement with the device, wherein the arrangement further comprises at least one coordinate measuring machine configured to perform the measurement of the workpiece(s) and to generate corresponding measurement data. For example, the measurement data may be raw measurement data or data concerning the coordinates of measuring points. It is also possible for the coordinate measuring machine to generate and output the workpiece coordinates required for the determination described above. Furthermore, the generated measurement data can be produced by measuring the workpiece to be measured or a workpiece of the same type according to the inspection plan in order to determine a value of the inspection characteristic included in the inspection plan or confirmed as part of the inspection plan from the generated measurement data.

[0053] Alternatively or additionally, the database containing the majority of the data records can be part of the arrangement.

[0054] As mentioned above, the invention relates to a device according to claim 9 for carrying out the method in one of the ways and embodiments described in this description, wherein the device includes, among other things: An access device configured to access a database containing a plurality of data records, each containing data about: a) at least two geometric elements that a workpiece may have, b) at least one geometric relationship between the at least two geometric elements, wherein the geometric relationship is a dimensional relationship that thus allows, for a workpiece to be measured, the determination of whether the geometric relationship exists by determining and evaluating the coordinates of the at least two geometric elements, c) at least one test characteristic assigned to the at least two geometric elements, which is verifiable with respect to the at least two geometric elements for a workpiece to be tested, an evaluation device configuredTo determine workpiece coordinates for a workpiece to be measured by evaluating measurement data of the workpiece to be measured and / or planning data of the workpiece to be measured; to use a detection device configured to determine, based on the workpiece coordinates, whether the workpiece to be measured has at least two geometric elements and at least one geometric relationship of at least one of the plurality of data sets, and to generate a corresponding detection result; and to use a test plan device configured, depending on the detection result with regard to the respective data set, to include at least one assigned test characteristic or at least one of the assigned test characteristics in a test plan for measuring the workpiece to be measured or for measuring a workpiece of the same type, or to confirm it as part of the test plan.

[0055] Further developments and refinements of the device and an arrangement with the device result from further developments and refinements of the method, and vice versa. For example, as mentioned, the device can be part of an arrangement that includes at least one coordinate measuring machine, and the coordinate measuring machine, or at least one of the coordinate measuring machines, can be designed or used to measure the workpiece to be measured and to generate the measurement data so that the evaluation unit, which evaluates the measurement data, can determine the workpiece coordinates.

[0056] As previously mentioned, tolerances must be considered in the measurement and manufacturing of workpieces. When defining the respective tolerance, a compromise must be found between striving for a workpiece manufactured with as few tolerances as possible, on the one hand, and feasibility and effort, on the other. Therefore, in many cases, the planning data for the manufacturing of workpieces defines permissible tolerances. The existing data records stored in the database may thus already contain a permissible tolerance in relation to the associated inspection characteristic. However, it is also possible to define the permissible tolerance later or to determine it from the planning data for the manufacturing of the workpiece.

[0057] An embodiment of the invention will now be described with reference to the accompanying drawing. The individual figures in the drawing show: Fig. 1 a coordinate measuring machine, which in the present embodiment is only a classic coordinate measuring machine in portal design, Fig. 2 schematically a computer which has various devices for carrying out the method according to the invention, Fig. 3 a wrench with an open end and a ring end, each for contacting the head of a hexagon screw or a corresponding nut, Fig. 4 geometric elements which the in Fig. 3 The wrench shown in Fig. 5 is characterized as a wrench with a jaw at each opposite end of the handle area, and it is determined for this wrench which of the geometric elements from Fig. 4 it corresponds to and which of the geometric relationships defined for these geometric elements it corresponds to, Fig. 6 a flowchart which schematically shows a procedure for identifying an existing data set based on geometric elements and a geometric relationship of the geometric elements, Fig. 7 an arrangement of geometric elements defined in an existing data set, and Fig. 8 an arrangement of geometric elements of a workpiece to be measured.

[0058] Fig.1 Figure 1 schematically shows a coordinate measuring machine 1 in a portal design. A first carriage 3, in the form of a portal, is movably guided along two parallel guides in the area of ​​a measuring table 2 (e.g., a granite slab). A first scale 4 is provided for measuring the position of the portal according to a first linear axis of movement y. The position is read with a corresponding reading sensor (not shown), as is the case with further scales, which are described below. A first drive (not shown) is also provided, which can drive the movement of the first carriage 3 in the y-direction.

[0059] A second carriage 5 is movably guided along the horizontal traverse of the portal-shaped first carriage 3, which spans the measuring table 2. To measure its position relative to the portal along a second linear axis of movement x, a second scale 6 and a corresponding second reading sensor (not shown) are provided. Movement of the second carriage 5 in the x-direction can be driven by a second drive (not shown).

[0060] A third slide, namely a quill 7, is movably guided on the second slide 5. To measure the position of the quill relative to the second slide 5 along a third linear axis of movement z, a third scale 8 and a corresponding third reading sensor (not shown) are provided. Movement of the quill 7 in the z-direction can be driven by a third actuator. A measuring sensor 10 is arranged below the lower end of the quill 7. In this case, it is designed as a stylus with a probe ball (i.e., as a tactile sensor), which is attached, for example, via a measuring head and an interchangeable interface at the lower end of the quill 7.

[0061] A workpiece 12 is arranged on the measuring table 2. The measuring sensor 10 can scan the workpiece by moving the three slides 3, 5, 7. Measured values ​​on the surface of the workpiece 12 are determined from the signals of the measuring sensor 10 and / or the measuring head, as well as from the scale positions of the scales 4, 6, 8. A control system, implemented by a computer program running on a control computer 14, controls and / or regulates the drives of the slides 3, 5, 7. A measuring computer 17 can be connected to the control system. The measuring computer receives and processes the scale values ​​read from the scales 4, 6, 8, as well as the signals from the measuring sensor 10 and / or the measuring head, to generate the coordinates of the measuring points on the surface of the workpiece 12 measured by the measuring sensor 10.

[0062] Especially the one in Fig. 1 The measuring computer 17 shown, or another measuring computer or an arrangement of measuring computers, can include the access device for accessing the database, the evaluation device for determining the workpiece coordinates, the verification device for determining whether the workpiece to be measured corresponds to at least one of the multiple data records, and the inspection plan device for recording at least one inspection characteristic from the data record in the inspection plan or for confirming at least one inspection characteristic as part of the inspection plan. Alternatively, the measuring computer or the arrangement of measuring computers can include at least some of these devices, in particular the evaluation device for determining the workpiece coordinates. In contrast, the access device, the verification device, and the inspection plan device can be implemented together on at least one other computer or on at least one other arrangement of computers.

[0063] Fig. 2 schematically shows a computer, in which an exemplary embodiment is shown in Fig. 1 The computer shown is 17. The computer has the access device designated by reference numeral 15, the locking device designated by reference numeral 16, and the test plan device designated by reference numeral 18. The device implemented outside the computer is shown above. Fig. 2 The evaluation unit 13 is shown. As indicated by an arrow pointing downwards towards the access unit 15, the access unit 15 receives the workpiece coordinates from the evaluation unit 13 during its operation. Furthermore, the access unit 15 receives the data from the database 19 or accesses these data records. Alternatively, the detection unit 16 can receive the workpiece coordinates directly from the evaluation unit 13 and also receive the data from the access unit 15, which is connected to the detection unit 16 in any case. The detection result(s) are transmitted by the detection unit 16 to the inspection plan unit 18 connected to it.This incorporates at least one assigned test characteristic, or at least one of the assigned test characteristics, into a test plan for measuring the workpiece to be measured or for measuring a workpiece of the same type, depending on the finding result with regard to the respective data set, or confirms it as part of the test plan. Starting from the test plan device 18 below in . Fig. 2 The arrow pointing to the right indicates that corresponding information or data can be output by the inspection plan device 18. This could, for example, be the inspection plan itself. If several data records from database 19 are identified as corresponding to the workpiece to be measured, several inspection characteristics will also be included in the inspection plan and / or confirmed as part of the inspection plan.

[0064] The following describes examples of implementation for data sets and corresponding workpieces. Fig. 3 Figure 21 shows a wrench 21 having an open end 22 at its left end and a ring 23 at its right end. Both the open end 22 and the ring 23 are suitable for contacting the head of a hexagonal screw of a size corresponding to the inner dimensions of the open end 22 and the ring 23, respectively, so that the screw can be turned in the desired direction. The long edges of the handle area of ​​the wrench 21 run parallel to each other, as is usual.

[0065] Fig. 4 Figure 1 shows geometric elements corresponding to the long edges of the handle area, the mouth 22, and the ring 23. Corresponding straight lines 24 and 25 of equal length and parallel to each other correspond to the long edges of the handle area; two short straight lines 26 and 27 of equal length and parallel to each other correspond to the inner edges of the mouth 22; and two concentric circles 28 and 29 correspond to the ring 23. The dashed line of symmetry is shown for the straight lines 24 and 25. The dashed line of symmetry is also shown for the short straight lines 26 and 27 of the inner edges of the mouth 22. The inner circle 28 of the mutually concentric circles 28, 29 represents a reconciling circle for the inner surface of the ring 23. For example, the inner circle 28 touches each of the segments that form the inner surface of the ring 23 at the point of the segment that is closest to the common center of the circles 28, 29.The outer circle 29 of the mutually concentric circle lines 28, 29 corresponds to the outer edge of the ring 23.

[0066] From these geometric elements (the long straight lines 24, 25, the short straight lines 26, 27, and the concentric circles 28, 29), the following datasets can be generated, in particular, whereby several of the datasets described below can optionally be combined into a single dataset: The first dataset concerns the mouth 22 and contains the data of the geometric elements that each define one of the short straight lines 26, 27. Furthermore, the dataset defines that the two straight lines run parallel to each other. However, this leaves open the question of the distance between the short straight lines 26, 27 and, in particular, the ratio of their length to their distance. Defining the length of the distance or the aforementioned ratio is necessary to geometrically characterize the mouth 22.Therefore, in the embodiment described here, the following geometric relationships are defined as part of the first data set: The length of the short straight lines 26, 27 is x, where x is a value of a defined dimension. This value of the defined dimension can either be specified in the data set or left blank, for example, if the data set is intended to define congruent jaws of different sizes for wrenches after multiplication by a scaling factor. Furthermore, it is defined as a geometric relationship that the distance is equal to the length of the short straight lines 26, 27 multiplied by a factor, which in this embodiment is 1.3, such that the distance A is equal to the length x multiplied by 1.3, or A = 1.3 * x.This geometric relationship is a dimensional geometric relationship between the two geometric elements (the short, parallel straight lines 26, 27).

[0067] The second data set concerns the orientation of the jaw 22, which is angled relative to the longitudinal direction of the wrench (for example, defined by the direction of the long straight lines 24, 25). Fig. 5 This angled design of the mouse 22 is achieved by an inclination relative to the horizontal. Fig. 5 Recognizable with an inclination angle α of 15 degrees. Shown in Fig. 5 The dashed lines on the left of the figure are extensions of the upper long straight line 24 and the upper short straight line 26. These extensions enclose the angle of inclination α. ​​The second data set therefore contains, as geometric element data, the data of at least one of the long straight lines 24, 25 and one of the short straight lines 26, 27. Furthermore, the second data set contains the geometric relationship between at least these lines 24 or 25 on the one hand and 26 or 27 on the other, such that they enclose an angle of 15 degrees. In this case, the dimension of the dimensional relationship is the angle for which the value 15 degrees is defined.

[0068] The third data set concerns ring 23. As geometric elements, the third data set defines circles 28 and 29. As geometric relationship(s), the third data set defines that circles 28 and 29 are concentric to each other and that, furthermore, the diameter (or alternatively, the radius) of the outer circle 28 is 1.4 times the diameter (or radius) of the inner circle 29. The dimension is thus that of the diameter and therefore of a length, whereby only the ratio of the lengths is defined in the third data set. Alternatively, values ​​could be defined for both the outer circle 28 and the inner circle 29.

[0069] In the exemplary embodiment, for example, the first data set is assigned the test characteristic "parallelism of the short straight lines 26, 27" and "straightness of the short straight lines 26, 27". The second data set is also assigned these test characteristics of parallelism and straightness, both with respect to the long straight lines 24, 25 and with respect to the short straight lines 26, 27, and is additionally assigned the test characteristic of the "inclination" or development of the jaw relative to the grip area. The third data set is assigned the characteristic of the concentricity of the circles 28, 29 as well as the so-called two-point dimension, each with respect to the individual circles 28, 29. The two-point dimension is the deviation of two points that are opposite each other in the direction of a line passing through the center of the circle, on the respective circle 28, 29 from the diameter.

[0070] In particular, the three data sets mentioned above can be stored in a database, although in practice a large number of other data sets are stored in the database. If a workpiece, as in Fig. 5 The data set to be measured, namely a wrench 31, can be determined based on planning data of the wrench 31 to be measured or based on the result of the measurement of the wrench 31, which data sets the wrench 31 to be measured corresponds to.

[0071] The in Fig. 5 The wrench shown, 31, unlike the one in Fig. 3 The illustrated wrench 21 has a jaw 32, 34 at each end. Thus, the wrench 31 lacks the ring 23 at the right end of the wrench 21. Fig. 3 When checking which of the data records stored in the database corresponds to the wrench from Fig. 5 Since the third data set does not correspond, no positive finding result is obtained with regard to the third data set, and the third data set is excluded as a source for the test characteristics assigned to it. In contrast, with regard to the mouths 32, 34, both the first and the second data set can be identified as corresponding. More specifically, in the embodiment described here, it is therefore determined that for each of the mouths 32, 34, the short straight lines 26, 27 from Fig. 4 as geometric elements, and that the distance between the short straight lines 26, 27 is equal to their length multiplied by 1.3. Therefore, each of the two mouths 30, 34 corresponds to the first data set. Furthermore, with respect to each of the mouths 32, 34, both the long straight lines 24, 25 and the short straight lines 26, 27 are present as geometric elements, and for each of the mouths 32, 34, one of the short straight lines 26, 27 forms an angle of 15 degrees with one of the long straight lines 24, 25. Therefore, with respect to the grip area, each of the two mouths 30, 34 also corresponds to the second data set.

[0072] Thus, in the embodiment, the above-mentioned test characteristics "parallelism of the short straight lines 26, 27" and "straightness of the short straight lines 26, 27" (with respect to each of the two jaws 32, 34) of the first data set, as well as the test characteristics "parallelism of the long straight lines 24, 25", "straightness of the long straight lines 24, 25" and "incline of the jaw relative to the handle area" of the second data set can be selected, in particular to include them in a test plan of the wrench 31 to be measured or to confirm them as test characteristics of the test plan.

[0073] The previously described embodiments can be extended as follows: For example, a data set defined with respect to wrenches can define additional geometries (or at least one of these geometries can be defined in a further data set), e.g., a circular arc adjacent to the two straight lines, corresponding to the path of the closed end of the wrench. A geometric relationship of the data set can be defined such that the points of intersection of the straight lines with the circular arc occupy a predefined position in the direction of the jaw opening.

[0074] Finally, the advantages and other aspects of the invention should be highlighted. Previously, the creation of a test plan for a workpiece to be measured was sometimes a manual process. The designer / metrologist could draw on their experience. The specification of test characteristics depended significantly on their knowledge. It cannot be expected that a single person possesses all the knowledge of previous workpiece tests. With the present invention, this expert knowledge can be systematically recorded, stored centrally, and used automatically for the identification of test characteristics.

[0075] Fig. 6 This schematically represents a procedure for identifying an existing data set based on geometric elements and a geometric relationship between those elements. The procedure can be executed automatically, for example, by a computer program running on a single computer or a network of computers. After the procedure is started in step S1, one of several stored data sets is selected in step S2. Optionally, the selection can be made based on additional information. Alternatively, the subsequent steps of the procedure can be executed for each of the stored data sets. That is, step S2 can be executed repeatedly, each time followed by steps S3 and S4.

[0076] In the following step S3, the geometric elements defined in the dataset are searched for in the information available about the workpiece. The search space consists of a set of geometric elements that are part of the aforementioned available information about the workpiece or are derived from this information. For example, the geometric elements "cylinder" and "planar surface" are available if a workpiece has at least one cylindrical bore in a cuboid block. The geometric element "cylinder" corresponds to the cylindrical bore, while the geometric element "planar surface" corresponds to the outer surfaces of the cuboid block. Therefore, it is present multiple times in this example.

[0077] In the following step S4, the search space is restricted, i.e., elements of the specified set that do not correspond to the dataset are eliminated. This can include eliminating geometric elements that are not contained in the dataset, as well as geometric elements for which the geometric relationship between at least two geometric elements defined in the dataset is not satisfied. Alternatively, or in addition to eliminating elements, elements (i.e., geometric elements) that correspond to the dataset can be identified, and in particular, those elements for which the at least one geometric relationship between at least two geometric elements defined in the dataset is satisfied.

[0078] In particular, by repeatedly executing step S4, either so many geometric elements are eliminated from the set that there can no longer be a match between the workpiece and the data set, or geometric elements remain and / or are identified for which at least one geometric relationship between at least two geometric elements defined in the data set also applies. Specifically, the set of geometric elements may also contain several groups of at least two geometric elements each, for which at least one geometric relationship applies. If, after reducing the search space by at least one execution of step S4 or by repeatedly executing step S4, at least one such group remains, then the data set from the workpiece has been identified accordingly, and the at least one associated inspection characteristic can be transferred to an inspection plan.be confirmed as belonging to the test plan.

[0079] Based on the Fig. 7 und 8 A concrete example of steps S3 and S4 will now be described for an existing data set and a workpiece to be measured. According to the existing data set (as Fig. 7 (shows) five cylinders are present as geometric elements. Each of the cylinders 40 to 44 can be defined by the radius of the depicted circular cross-section and by its length (in a direction perpendicular to the plane of the figure). Fig. 7 , for example, defined by the length of the longitudinal axis). According to the available data set, cylinders 40 to 44 have the same orientation in space, have the same position in space with respect to a distinguished point (for example, the starting point of the longitudinal axis) in their longitudinal direction, have the same diameters or radii, and have the same length in their longitudinal direction. Furthermore, the peripheral cylinders 41 to 44 are the same distance from the centrally located cylinder 40 and are each the same distance from their nearest adjacent cylinder on the periphery of the centrally located cylinder 40. For example, the distances between cylinders 41 and 42, and between cylinders 43 and 44, are therefore equal. The data set also includes a test characteristic related to the positions of cylinders 40 to 44, which concerns the distance between the cylinders.It further stipulates that the positions of the cylinders 41 to 44 located in the periphery should not deviate from their target position by more than a specified maximum value (whose value may be specified in the data set) of the position tolerance.

[0080] The workpiece to be measured, on the other hand, has nine cylinders 50 to 58 aligned parallel to each other, as Fig. 8 This shows that these nine cylinders 50 to 58 also have the same orientation in space, the same position along their longitudinal axes, the same diameter, and the same length. Furthermore, the cylinders 51 to 58 located at the periphery are each the same distance from the cylinder 50 located in the central area and also the same distance from their nearest peripheral cylinder. Additionally, there are two further cylinders 59 and 60 whose longitudinal axes are perpendicular to the longitudinal axes of the nine cylinders 50 to 58.

[0081] Therefore, during step S3, eleven geometric elements ("cylinders") are determined for the workpiece to be measured. During step S4, the nine cylinders 50 to 58 are identified as corresponding to the existing data set. The tenth cylinder, 59, and the eleventh cylinder, 60, are excluded from the search space of geometric elements because too few of the geometric relationships defined in the given data set apply to these cylinders 59 and 60. In particular, a central cylinder is missing. In practice, the workpiece to be measured may contain further geometric elements, which are either identified as corresponding to another given data set or removed from the search space of geometric elements for each given data set.

[0082] In particular, during the execution of step S4, it is possible that two parts of the entire search space exist, either temporarily or until the completion of step S4. In one part, the nine cylinders 50 to 58 are located in the exemplary embodiment. In the other part, the tenth cylinder 59 and the eleventh cylinder 60 are temporarily located in the exemplary embodiment. However, cylinders 59 and 60 are eliminated from this other part of the search space as soon as it is determined that essential geometric relationships defined in the given data set do not apply to them. The other part of the search space then becomes empty.

[0083] There can now be a modified definition of the existing data set, in which the above applies and, in addition, a value for the distance between the peripherally located cylinders 41 to 44 is defined, or alternatively, a ratio of the distances between the nearest adjacent peripherally located cylinders 41 to 44 to each other to the distance of these peripherally located cylinders 41 to 44 to the centrally located cylinder 40. In this case, the nine cylinders 50 to 58 of the workpiece to be measured would not satisfy all the geometric relationships between the geometric elements defined in the data set, namely not the aforementioned additionally defined feature. However, a selection of the nine cylinders 50 to 58 would also correspond to this existing data set, i.e., satisfy all defined geometric relationships. This selection consists of cylinders 50, 51, 53, 55, and 57. With appropriate design of the search algorithm, or...The identification algorithm for implementing step S4 could therefore also identify this selection of cylinders 50, 51, 53, 55, and 57 as corresponding to the existing data set. For this purpose, the algorithm could, for example, include a step in which, for a first cylinder located at the periphery, e.g., cylinder 53, another cylinder is sought that is located at the periphery of the central cylinder 50 and that lies at the distance specified by the data set from the first cylinder located at the periphery. This applies to cylinders 51 and 55 with respect to cylinder 53. A similar procedure would have to be followed for further cylinders at the periphery. It should be noted that not only the aforementioned selection of five cylinders fulfills the modified definition of the existing data set, but also the selection of the five cylinders 50, 52, 54, 56, and 58. In step S4, these two selections are therefore...Groups of five cylinders each were identified.

[0084] Optionally, in step S4 or in another configuration of the procedure, a partial match with the existing data set can also be determined if the geometric elements of the workpiece to be measured do not fulfill all the geometric relationships to each other that are defined in the data set. Referring to the previous example with the modified definition of the existing data set, the test result can also be issued for the nine cylinders 50 to 58, indicating that there is a high degree of match with the geometric relationships defined in the data set, but that the distance between the cylinders 41 to 44 located at the periphery does not correspond to the data set. The aforementioned associated test characteristic of the distance with a specific positional tolerance can also be meaningfully applied in this case.

[0085] This is an example of how, even if a workpiece deviates from the definition in the existing data set, at least one assigned inspection characteristic can be included in the inspection plan, or this inspection characteristic can be confirmed in the inspection plan. Optionally, geometric relationships in the existing data set can be marked, for example, as dispensable if all other geometric relationships are satisfied, or alternatively, marked as essential. If an essential geometric relationship is not satisfied, no match with the existing data set will be found.

Claims

1. Method of using a coordinate measuring machine (1) to measure a workpiece (31) to be measured, wherein - a database (19) is accessed in which a plurality of data records are stored, each containing data on: a) at least two geometric elements (24 to 29) which a workpiece might contain, b) at least one geometric relationship of the at least two geometric elements (24 to 29) in relation to one another, the geometric relationship being a dimensional relationship thus allowing determination as to whether the geometric relationship exists in a workpiece to be measured, by way of ascertaining and evaluating coordinates of the at least two geometric elements (24 to 29), c) at least one test feature assigned to the at least two geometric elements (24 to 29), said at least one test feature being testable with respect to the at least two geometric elements (24 to 29) for a workpiece (31) to be tested, - workpiece coordinates are ascertained for a workpiece (31) to be measured, by evaluating measurement data of the workpiece (31) to be measured and / or planning data of the workpiece (31) to be measured, - the workpiece coordinates are used to determine whether the workpiece to be measured contains the at least two geometric elements (24 to 29) and the at least one geometric relationship of at least one of the plurality of data records, and a corresponding determination result is created, - depending on the determination result in relation to the respective data record, the at least one assigned test feature or at least one of the assigned test features is incorporated in a test plan for measuring the workpiece (31) to be measured or for measuring a workpiece of the same type or is confirmed as part of the test plan, characterized in that - there is an ascertainment of a plurality of the data records stored in the database (19), which each define data record geometric elements (24 to 29) corresponding to the same plurality of geometric elements (24 to 29) of the workpiece (31) to be measured and which also each define the geometric relationship for these data record geometric elements (24 to 29), wherein a measure for a correspondence of the geometric elements (24 to 29) and the geometric relationship is ascertained for each of the plurality of ascertained data records and wherein the measure of correspondence is used to ascertain at least one of the plurality of ascertained data records as non-corresponding or having a lower correspondence than at least one other data record of the plurality of ascertained data records.

2. Method according to Claim 1, wherein at least one of the data records in the database (19) contains, besides the data on the at least one assigned test feature, additional information concerning the implementation of the measurement of the workpiece or a reference regarding the additional information and wherein, depending on the determination result, the additional information is incorporated in the test plan and / or a measurement plan, corresponding to the test plan, for measuring the workpiece (31) to be measured or for measuring a workpiece of the same type and / or is confirmed as part of the test plan.

3. Method according to Claim 1 or 2, wherein, when determining whether the workpiece to be measured contains the at least two geometric elements (24 to 29) and the at least one geometric relationship of at least one of the plurality of data records, there is an initial determination with respect to one of the data records as to whether the workpiece to be measured contains all the geometric elements (24 to 29) for which the geometric relationship of the geometric elements (24 to 29) is defined in relation to one another in the data record and, if so, there is a subsequent determination as to whether the geometric relationship exists for the geometric elements (24 to 29) of the workpiece (31) to be measured.

4. Method according to any of the preceding claims, wherein the data record with the highest measure of correspondence is selected from the plurality of ascertained data records and the at least one assigned test feature or at least one of the assigned test features of this selected data record is incorporated in the test plan for measuring the workpiece to be measured or for measuring a workpiece of the same type or is confirmed as part of the test plan.

5. Method according to any of the preceding claims, wherein the workpiece (31) to be measured is measured by means of at least one coordinate measuring machine (1), and the measurement data are created to ascertain the workpiece coordinates.

6. Method according to any of the preceding claims, wherein the workpiece (31) to be measured or a workpiece of the same type is measured by means of at least one coordinate measuring machine (1) according to the test plan, and / or a value of the test feature incorporated in the test plan or confirmed as part of the test plan is ascertained.

7. Computer program comprising commands that, upon execution of the program by a computer or by an arrangement of computers, prompt the said computer or arrangement of computers to carry out the method according to any of Claims 1 to 4.

8. Computer-readable storage medium comprising commands that, upon execution by a computer or by an arrangement of computers, prompt the said computer or arrangement of computers to carry out the method according to any of Claims 1 to 4.

9. Apparatus for carrying out the method according to any of the preceding claims, wherein the apparatus comprises: - an access device (15) configured to access a database (19) in which a plurality of data records are stored, each containing data on: a) at least two geometric elements (24 to 29) which a workpiece might contain, b) at least one geometric relationship of the at least two geometric elements (24 to 29) in relation to one another, the geometric relationship being a dimensional relationship thus allowing determination as to whether the geometric relationship exists in a workpiece to be measured, by way of ascertaining and evaluating coordinates of the at least two geometric elements (24 to 29), c) at least one test feature assigned to the at least two geometric elements (24 to 29), said at least one test feature being testable with respect to the at least two geometric elements (24 to 29) for the workpiece, - an evaluation device (13) configured to ascertain workpiece coordinates for a workpiece to be measured, by evaluating measurement data of the workpiece (31) to be measured and / or planning data of the workpiece (31) to be measured, - a determination device (16) configured to use the workpiece coordinates to determine whether the workpiece to be measured contains the at least two geometric elements (24 to 29) and the at least one geometric relationship of at least one of the plurality of data records, and to create a corresponding determination result, and - a test plan device (18) configured, depending on the determination result in relation to the respective data record, to incorporate the at least one assigned test feature or at least one of the assigned test features in a test plan for measuring the workpiece (31) to be measured or for measuring a workpiece of the same type or to confirm this as part of the test plan, characterized in that the apparatus is configured to ascertain a plurality of the data records stored in the database (19), which each define data record geometric elements (24 to 29) corresponding to the same plurality of geometric elements (24 to 29) of the workpiece (31) to be measured and which also each define the geometric relationship for these data record geometric elements (24 to 29), wherein the apparatus is further configured to ascertain a measure for a correspondence of the geometric elements (24 to 29) and the geometric relationship for each of the plurality of ascertained data records and to use the measure of correspondence to ascertain at least one of the plurality of ascertained data records as non-corresponding or having a lower correspondence than at least one other data record of the plurality of ascertained data records.

10. Apparatus according to Claim 9, wherein the apparatus is configured to select the data record with the highest measure of correspondence from the plurality of ascertained data records and to incorporate the at least one assigned test feature or at least one of the assigned test features of this selected data record in the test plan for measuring the workpiece to be measured or for measuring a workpiece of the same type or to confirm this as part of the test plan.

11. Arrangement having an apparatus according to Claim 9 or 10, wherein the arrangement further comprises: - at least one coordinate measuring machine (1) configured to carry out the measurement of the workpiece(s) and to create corresponding measurement data, and / or - the database (19) with the plurality of the data records.