Method for Determining Dimensional Properties Of a Measurement Object Using a Coordinate Measuring Machine

Abstract

A method includes receiving a command designating a desired measurement path, including desired start and end positions. The method includes searching a data memory to find a first measurement path corresponding to the command. The first measurement path includes first start and end positions. The method includes, in response to the search being successful (the first measurement path corresponds to the command), reading the first measurement path and controlling a measuring head of a coordinate measuring machine to move along the first measurement path to capture a measurement point on the measurement object. The method includes, in response to the search being unsuccessful, calculating a second measurement path, storing the second measurement path in the data memory, and moving the measuring head along the second measurement path to capture the measurement point. The method includes determining dimensional properties of the measurement object based on the measurement point.

Claims

1. A method for determining dimensional properties of a measurement object using a coordinate measuring machine, the coordinate measuring machine including a measuring head movable with respect to the measurement object, the method comprising: receiving an input command including an information item representing a desired measurement path from a desired start position to a desired end position; searching a data memory to find a first predefined measurement path corresponding to the information item, wherein the data memory stores a plurality of predefined measurement paths each including a respective predefined start position and a respective predefined end position, and wherein the first predefined measurement path includes a first start position and a first end position; in response to the search being successful such that the first predefined measurement path corresponds to the information item: reading the first predefined measurement path from the data memory, and moving the measuring head along the first predefined measurement path from the first start position to the first end position and capturing at least one measurement point on the measurement object; in response to the search being unsuccessful such that no predefined measurement path corresponding to the information item is found: calculating a second measurement path with a second start position and a second end position based on the input command, storing the second measurement path in the data memory, and moving the measuring head along the second measurement path from the second start position to the second end position and capturing the at least one measurement point; and determining the dimensional properties of the measurement object based on the captured at least one measurement point.

2. The method of claim 1 wherein: the information item includes at least one predefined tolerance, and the search is determined to be successful in response to both of: the desired start position and the first start position corresponding within the at least one predefined tolerance, and the desired end position and the first end position corresponding within the at least one predefined tolerance.

3. The method of claim 2 further comprising: in response to the search being unsuccessful, searching the data memory for a third predefined measurement path having a fourth start position and a fourth end position, such that the desired start position and the fourth end position correspond within the at least one predefined tolerance and the desired end position and the fourth start position correspond to one another within the at least one predefined tolerance; and in response to the third predefined measurement path being found: reading the third predefined measurement path from the data memory, inverting the third predefined measurement path to obtain an inverted third measurement path starting from the fourth end position and leading to the fourth start position, and moving the measuring head along the inverted third measurement path from the fourth end position to the fourth start position and capturing the at least one measurement point.

4. The method of claim 2 further comprising adapting at least one of the first start position and the first end position to compensate for the at least one predefined tolerance.

5. The method of claim 1 further comprising, in response to the search being successful: calculating the second measurement path based on the input command; comparing the first predefined measurement path and the second measurement path; storing the second measurement path in the data memory; in response to the second start position having a smaller deviation from the desired start position than the first start position has from the desired start position, moving the measuring head along the second measurement path; and in response to the second end position having a smaller deviation from the desired end position than the first end position has from the desired end position, moving the measuring head along the second measurement path.

6. The method of claim 1 further comprising, in response to the search being successful: optimizing the first predefined measurement path to determine a first optimized measurement path; and moving the measuring head along the first optimized measurement path from the first start position to the first end position.

7. The method of claim 1 wherein: the data memory has a predefined storage capacity; and the predefined storage capacity is determined by a predefined number of storable, predefined measurement paths.

8. The method of claim 7 further comprising, in response to the predefined number of storable, predefined measurement paths having been reached: identifying at least one stored, predefined measurement path that has not been selected within a predefined number of searches of the data memory; and deleting the at least one stored, predefined measurement path.

9. The method of claim 7 further comprising, in response to the predefined number of storable, predefined measurement paths having been reached: determining a shortest measurement path of the stored, predefined measurement paths; and deleting the shortest measurement path.

10. The method of claim 1 wherein at least some of the plurality of predefined measurement paths include at least one of: a displacement speed of the measuring head for one or more path sections between the respective start and end positions; a travel between the respective start and end positions; a tolerance value for the respective start positions; a tolerance value for the respective end positions; a collision object arranged between the respective start and end positions; a rotary angle along a kinematic chain of the coordinate measuring machine; and a movement preference for a movement sequence of movement axes of the coordinate measuring machine.

11. The method of claim 1 further comprising: determining a respective key value based on the respective predefined start position and end position and the plurality of predefined measurement paths, wherein each measurement path in the data memory is identified by the respective key value.

12. The method of claim 11 wherein the respective key value is further determined based on a predefined tolerance.

13. The method of claim 11 wherein: the data memory is formed as a hash table in which the plurality of predefined measurement paths are stored, a respective index value is assigned to each of the predefined measurement paths, the method comprises, for each of the plurality of predefined measurement paths, calculating an associated hash value based on the respective key value using a hash function, the respective hash value defines the respective index value, and the respective measurement path is accessed via the respective hash value in the hash table.

14. The method of claim 1 wherein the data memory is implemented as a database.

15. The method of claim 14 further comprising maintaining the database.

16. An apparatus for determining dimensional properties of a measurement object, the apparatus comprising: a workpiece receptacle configured to hold the measurement object; a measuring head configured to capture at least one measurement point on the measurement object, wherein the measuring head is displaceable relative to the workpiece receptacle; a plurality of drives configured to displace the measuring head along a plurality of movement axes; an evaluation and control unit configured to control the plurality of drives and to receive a measurement signal that the measuring head generates when capturing the at least one measurement point; and a data memory including a database configured to store a plurality of predefined measurement paths each including a respective predefined start position and a respective predefined end position, wherein the evaluation and control unit is configured to: receive an input command including an information item representing a desired measurement path from a desired start position to a desired end position; search the database to find a first predefined measurement path corresponding to the information item, wherein the first predefined measurement path includes a first start position and a first end position; in response to the search being successful such that the first predefined measurement path corresponds to the information item: read the first predefined measurement path from the database, and move the measuring head along the first predefined measurement path from the first start position to the first end position and capture the at least one measurement point; in response to the search being unsuccessful such that no predefined measurement path corresponding to the information item is found: calculate a second measurement path with a second start position and a second end position based on the input command, store the second measurement path in the database, and move the measuring head along the second measurement path from the second start position to the second end position and capture the at least one measurement point; and determine the dimensional properties of the measurement object based on the captured at least one measurement point.

17. A non-transitory computer-readable medium comprising instructions including: receiving an input command including an information item representing a desired measurement path from a desired start position to a desired end position; searching a data memory to find a first predefined measurement path corresponding to the information item, wherein the data memory stores a plurality of predefined measurement paths each including a respective predefined start position and a respective predefined end position, and wherein the first predefined measurement path includes a first start position and a first end position; in response to the search being successful such that the first predefined measurement path corresponds to the information item: reading the first predefined measurement path from the data memory, and moving a measuring head of a coordinate measuring machine along the first predefined measurement path from the first start position to the first end position and capturing at least one measurement point on a measurement object; in response to the search being unsuccessful such that no predefined measurement path corresponding to the information item is found: calculating a second measurement path with a second start position and a second end position based on the input command, storing the second measurement path in the data memory, and moving the measuring head along the second measurement path from the second start position to the second end position and capturing the at least one measurement point; and determining dimensional properties of the measurement object based on the captured at least one measurement point.

18. The computer-readable medium of claim 17 further comprising the data memory.

19. The computer-readable medium of claim 18 wherein the data memory is structured as a database.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0081] Example embodiments are illustrated in the drawing and will be explained in greater detail in the following description.

[0082] FIG. 1 shows one example embodiment of the novel apparatus, which can be used to perform the novel method;

[0083] FIG. 2 shows a schematic illustration of an ideal and a real measurement path on a measurement object;

[0084] FIG. 3 shows a schematic illustration of a random number-based measurement path calculation;

[0085] FIG. 4 shows a flowchart of a first example embodiment of the novel method;

[0086] FIG. 5 shows a flowchart of a second example embodiment of the novel method;

[0087] FIG. 6 shows a schematic illustration of a measurement path adaptation;

[0088] FIG. 7 shows a schematic illustration of an inverted measurement path;

[0089] FIG. 8 shows a schematic illustration of a measurement path modification on account of a collision object; and

[0090] FIG. 9 shows a tabular representation of a measurement path calculation by means of the novel method.

DETAILED DESCRIPTION

[0091] FIG. 1 shows a coordinate measuring machine or an apparatus on which the novel method for determining dimensional properties of a measurement object can be performed. The coordinate measuring machine is designated as a whole by the reference sign 100.

[0092] The coordinate measuring machine 100 comprises a base 10. The base 10 is preferably a stable plate, which is for example produced from granite. A workpiece receptacle 12 embodied to hold or receive a measurement object 14 is arranged on the base 10. To this end, one or more fastening elements 16 (e.g., clamps or screw clamps), for example, are provided on the workpiece receptacle, by means of which the measurement object 14 can be fastened, preferably in reversibly detachable fashion, to the workpiece receptacle 12. In the present case, the measurement object 14 is a ring gauge, as is used for calibrating coordinate measuring machines, for example.

[0093] A portal 18 is arranged on the base 10 such that it is displaceable in the longitudinal direction. The portal 18 serves as a movable support structure. The portal 18 has two columns projecting upward from the base 10, which are connected by a crossbeam and have an inverted U-shape overall.

[0094] The direction of movement of the portal 18 in relation to the base 10 is usually referred to as the Y-direction and is implemented by way of a first motor drive 20 (e.g., a stepper motor). In the present case, the first drive 20 is arranged in an end region, pointing to the base 10, of one of the downwardly directed columns and is configured to displace the portal 18 along the Y-direction. A carriage 22, which is displaceable in the transverse direction by way of a second motor drive 24, is arranged on the upper crossbeam of the portal 18. This transverse direction is usually referred to as the X-direction. In the present case, the second drive 24 is installed on the carriage 22. The carriage 22 carries a quill 26, which is movable in the Z-direction, i.e., perpendicularly to the base 10, by way of a third motor drive 28. The third drive 28 is integrated in the carriage 22. It should be mentioned that the drives 20, 24, 28 need not be arranged at the specified positions. By way of example, the third drive 28 can be installed in the quill 26.

[0095] Measurement devices on the basis of which the X-, Y- and Z-positions of the portal 18, the carriage 22 and the quill 26 can be determined are denoted by the reference signs 30, 32, 34. The measurement devices 30, 32, 34 are typically glass rulers, which serve as measuring scales. These measuring scales are formed in conjunction with corresponding reading heads (not shown here) to determine the respectively current position of the portal 18 in relation to the base 10, the position of the carriage 22 in relation to the upper crossbeam of the portal 18 and the position of the quill 26 in relation to the carriage 22.

[0096] A measuring head 36 is arranged at a lower, free end of the quill 26. The measuring head 36 is configured to capture measurement points on the measurement object 14. The measuring head 36 is part of a measurement sensor, the measurement sensor system of which can be arranged separately from the measuring head 36 or can be integrated in the latter and can be connected thereto by way of one or more cables or in wireless fashion. The measuring head 36 has a tactile stylus 38, which is directed downward in the Z-direction in the direction of the base 10. In other example embodiments, which are not shown, the measuring head 36 can also have a plurality of tactile and/or optical measurement heads, which can project in different spatial directions, for example. The stylus 38 is configured to probe a surface of the measurement object 14 by means of a probe head 40. By way of example, the probe head 40 is a ruby sphere.

[0097] It should be noted that by way of example a coordinate measuring machine 100 of a portal design is explained in FIG. 1. In principle, use can also be made of coordinate measuring machines 100 of a cantilever-arm, bridge or stand design. Depending on the type of construction of the coordinate measuring machine 100, the relative movement of the base 10 and the measuring head 36 along one, two or all three spatial directions can be implemented by a movability of the base 10 or the workpiece receptacle 12.

[0098] Alternatively, the coordinate measuring machine 100 can also be designed as an articulated arm system (for example of a robot) with a plurality of degrees of freedom. For example, the coordinate measuring machine 100 can be configured as a component of a robot, for example as a robot arm, on the end effector (not shown) of which the measuring head 36 is arranged. The term “coordinate measuring machine” is accordingly to be interpreted broadly as any type of system that is suitable for capturing coordinates of a measurement object.

[0099] When sensing the surface of the measurement object 14, the probe head 40 generates an electrical measurement signal, on the basis of which it is possible to ascertain the dimensional properties of the measurement object 14 to be measured. In other example embodiments, the geometry of the measurement object 14 to be measured can be ascertained optically by way of one or more cameras which, for example, are arranged on the free end of the quill 26. In order to approach the measurement points on the measurement object 14, the measuring head 36 is displaced relative to the workpiece receptacle 12 or to the measurement object 14 by means of the drives 20, 24, 28. To this end, the drives 20, 24, 28 receive control commands from an evaluation and control unit 42, 44, on the basis of which the drives 20, 24, 28 are driven in each case on their own or together (for example, by way of CNC driving).

[0100] In FIG. 1, the evaluation and control unit 42, 44 is connected to the coordinate measuring machine 100 by way of cables. A wireless connection is likewise conceivable. Moreover, it is possible for the evaluation and control unit 42, 44 to be integrated in the coordinate measuring machine 100 (e.g., in the base 10).

[0101] Here, the evaluation and control unit 42, 44 is represented in two parts and can contain a numerical machine controller 42 (computerized numerical controller) and a commercially available computer 44, which is provided with a commercially available operating system, such as Windows, OS X or Linux. The control commands for driving the drives 20, 24, 28 are preferably generated by a software application, which is executed on the computer 44. In principle, the computer 44 can also be integrated in the machine controller 42, or vice versa.

[0102] The CALYPSO software, marketed by the applicant, is an example software application. CALYPSO is software for planning measurement paths and for evaluating measurement points. A user creates a test plan by means of which the measurement object 14 should be measured, for example on the basis of CAD data of the measurement object. By means of the orientation to test features, CALYPSO makes it easier for the user to create/enter the measuring procedure because the test features generally correspond to specifications which the user can gather from a technical CAD drawing of the measurement object 14. With the selection of the test features, CALYPSO then creates the control commands which preferably express a measurement path with an associated start position and end position. The control commands are preferably transferred to the machine controller 42 by way of one or more cables or in wireless fashion.

[0103] The evaluation and control unit 42, 44 is configured to receive an input command, which represents a first start position 46, from which the measuring head 36 should be displaced, and a first end position 48, at which the measurement point on the measurement object 14 is captured (see FIG. 2). The input command can be generated with the aid of the test plan or can arise automatically from the test plan. The evaluation and control unit 42 then accesses a data memory 50, which is represented here within the machine controller 42 for reasons of simplicity. Alternatively, it could be contained in the computer 44 or could be implemented as external data memory, for instance as network storage. The data memory 50 can contain a volatile RAM memory and/or a non-volatile memory, for instance an SSD memory. A database with a plurality of predefined measurement paths is stored in the data memory 50.

[0104] The evaluation and control unit 42, 44 is further configured to search for a first predefined measurement path 52 (see FIG. 2) with a second start position 54 and a second end position 56 in the database. In the process, a check is carried out whether the first and the second start position 46, 54 and the first and the second end position 48, 56 correspond within a predefined tolerance 58 or whether a comparison information item corresponds with a predetermined information item from a test plan. As indicated in FIG. 2, the tolerance 58 has an X-component and a Y-component 58′, 58″ in the two-dimensional case (and accordingly a Z-component in the three-dimensional case as well) and, for example, describes a deviation between the second start position 54 and the first start position 46 and/or a deviation between the second end position 56 and the first end position 48, which can be measured, for example, in millimeters (mm) or degrees (°).

[0105] If the first and the second start position 46, 54 and the first and the second end position 48, 56 correspond within the predefined tolerance 58 and/or if the comparison information item corresponds with the predetermined information item, the evaluation and control unit 42, 44 reads the first measurement path 52 from the database and drives the drives 20, 24, 28 in order to move the measuring head 36 along the first measurement path 52 from the second start position 54 to the second end position 56.

[0106] By contrast, if the first and the second start position 46, 56 and/or the first and the second end position 48, 56 do not correspond within the predefined tolerance 58 and/or if the comparison information item does not correspond with the predetermined information item, a second measurement path 60 with a third start position 62 and a third end position 64 is calculated by the evaluation and control unit 42, 44 on the basis of the first start position 46 and the first end position 48. Advantageously, the second measurement path 60 is stored in the database. In this case, the machine controller 42 drives the drives 20, 24, 28 in such a way that the measuring head 36 is moved along the second measurement path 60 from the third start position 62 to the third end position 64.

[0107] The measurement point on the measurement object 14 is recorded in the form of the measurement signal after the second or third end position 56, 64 has been reached (depending on the case). Then, measurement software on the computer 44 determines the dimensional properties of the measurement object 14 on the basis of the measurement signal. It is understood that determining the dimensional properties can contain a plurality of measurement signals from a plurality of measurement points.

[0108] It should be mentioned that the recalculated third start position and third end position 62, 64 correspond in example fashion to the first start position and first end position 46, 48 in FIG. 2; however this corresponds to the rule, with certain exceptions. Since the calculation is implemented, as a rule, by means of a random number-based algorithm, however, this may be different in other example embodiments. This is because the random number-based calculation can lead to different measurement paths with different lengths or travels being calculated for one and the same start position and end position 46, 48. This is illustrated schematically in FIG. 3, wherein four measurement paths of different length are shown in example fashion for the entered first start position and first end position 46, 48. The movement of the measuring head 36 around the measurement object 14 (or around the safety square 14 in the case of FIG. 3) is in the clockwise direction for two measurement paths and in the anticlockwise direction for two measurement paths.

[0109] FIG. 4 shows a flowchart which illustrates an example embodiment of the novel method which can be performed on the novel apparatus 100. The input command representing the first start position 46 and the first end position 48 is received in a first step 1000. The database in which the plurality of predefined measurement paths are stored, each of the latter having a predefined start position and end position, is accessed in step 1100. The plurality of measurement paths emerge, for example, from preceding coordinate measurements. The database is searched for a first predefined measurement path 52 with the second start position 54 and the second end position 56 in step 1200. The search 1200 is implemented on the basis of whether the first and the second start position 46, 54 and the first and the second end position 48, 56 correspond within the predefined tolerance 58 and/or whether the comparison information item corresponds with the predetermined information item from the test plan, for example.

[0110] If the first and the second start position 46, 54 and the first and the second end position 48, 56 correspond within the predefined tolerance 58 and/or if the comparison information item corresponds with the predetermined information item from the test plan (“y” after step 1200), the first measurement path 52 has been found and the first measurement path 52 is read from the database in step 1300. In an optional step 1400, the second start position 54 and/or the second end position 56 can preferably be adapted for compensating the predefined tolerance 58, from which an adapted second start position and/or second end position 66, 68 emerge (see FIG. 6). As a rule, a plurality of intermediate positions between the respective start position and end position are also adapted, as illustrated in FIG. 9 in example fashion. Here, the second start position 54 corresponds to an original start position whereas the adapted second start position corresponds to an actual start position. An equivalent statement applies to the second and the adapted second end position 56, 68. Following the optional step 1400, the respectively adapted start position 66 can be compared to the first start position 46 and the respectively adapted end position 68 can be compared to the first end position 48 in a further optional step 1500. If the first and the adapted second start position 46, 66 and the first and the respectively adapted second end position 48, 68 correspond within the predefined second tolerance (“y” after step 1500), the adapted and/or compared measurement path 52′ can be optimized by an optimization algorithm in a further optional step 1600, wherein such an optimization yields, for example, a shortening of the adapted measurement path 52′, i.e., an optimized measurement path 52″ (see FIG. 6). Then, the measuring head 36 is moved along an adapted, compared and/or optimized measurement path 50, 52′ or 52″, depending on the optional embodiment, in step 1700. Subsequently, the measurement point on the measurement object 14 is recorded with the aid of the measuring head 36 in step 1800. The dimensional properties of the measurement object 14 are determined in step 1900 on the basis of the recorded measurement point. Preferably, it is not only one measurement point but a plurality of measurement points that are captured on the measurement object 14 and the overall geometry of the measurement object 14 is ascertained on the basis of the captured measurement points. Explicit reference is once again made to the fact that steps 1400, 1500, and 1600 are optional in each case and merely represent advantageous embodiments of the novel method. Consequently, none, or only one, of the steps 1400, 1500, and 1600 might be performed.

[0111] By contrast, if the first and the second start position 46, 54 and the first and the second end position 48, 56 do not correspond within the predefined tolerance 58 and/or if the comparison information item does not correspond with the predetermined information item from the test plan when searching through the database in step 1200 (“n” after step 1200), the first measurement path 52 has not been found in the database. In an advantageous yet optional step 2000, the database can however then be searched for a third predefined measurement path 70 with a fourth start position 72 and a fourth end position 74 in supplementary fashion, in which the first start position 46 and the fourth end position 74 and the first end position 48 and the fourth start position 72 correspond to one another within the predefined tolerance 58 (see FIG. 7). If the third predefined measurement path 70 is found in optional step 2000 (“y” after step 2000), the third measurement path 70 is read from the database and inverted in a subsequent, optional step 2100.

[0112] The fourth start position and fourth end position 72, 74 are interchanged such that a movement direction in which the measuring head 36 moves is likewise reversed. This is indicated schematically in FIG. 7 by a double-headed arrow. Following optional step 2100, at least one of steps 1400, 1500 or 1600 can optionally be carried out, or the method alternatively jumps directly to step 1700.

[0113] If no third measurement path 70 is found (“n” after step 2000), by contrast, the second measurement path 60 with a third start position 62 and a third end position 64 is calculated in step 2200 on the basis of the input command (see FIG. 7). In step 2300, the second measurement path 60 is stored in the database of the data memory 50. In step 2400, the measuring head is moved along the second measurement path 60 from the third start position 62 to the third end position 64. In this case (“n” after step 1200), steps 1800 and 1900 follow step 2400. It should be mentioned that step 1200 and optional step 2000 can be implemented at the same time or successively in time. Moreover, it should be mentioned that steps 2200, 2300, 2400, 1800, and 1900 are carried out in sequence after the aforementioned optional step 1500 in the case of a negative test result (“n” after step 1500). In the case where optional step 2000 is not implemented, the method jumps to step 2200 following an “n” after step 1200.

[0114] If no corresponding third measurement path was found after step 2000, it is advantageous to search for alternative measurement paths (fallback options) if the database access fails, i.e., no appropriate measurement path was found, and to adapt the alternative measurement paths to the boundary conditions which are determined by the first start position and first end position. Here it is conceivable for the search for such fallback options to be recursive and multi-stage, i.e., be accompanied by a plurality of iteration or search steps.

[0115] Additionally, a check can still be carried out after step 2100 as to whether the measuring path in step 1400 should be adapted, for example if a predetermined boundary condition is satisfied. Should this boundary condition not be satisfied, a second measurement path can then alternatively also be recalculated in step 2200 in place of the adaptation, and so the method would jump from step 2100 to step 2200 in this case (not illustrated).

[0116] FIG. 5 illustrates a flowchart of a second example embodiment of the novel method. Only differences to the first example embodiment shown in FIG. 4 are discussed in this case. According to the second example embodiment, the calculation of the second measurement path 60 as per step 2200 follows the check of the adapted measurement path in optional step 1500, independently of the outcome of this optional test. Optionally, there can be a comparison of the first measurement path 52 or the adapted measurement path 52′ with the calculated second measurement path 60 in an optional step 2500 that follows step 2200. Should the second measurement path 60 be better (“y” after step 2500), steps 2300, 2400, 1800, and 1900 are carried out in sequence. By contrast, if the second measurement path 60 is not better (“n” after step 2500), the optimization step 1600 can optionally be carried out or the method proceeds directly with steps 1700, 1800, and 1900. In the case where one or more optional steps can be skipped, this path is labeled by a solid arrow in the flowcharts, whereas optional step sequences are connected by dashed arrows.

[0117] FIG. 8 shows a first measurement path 52, retrieved from the memory, between the second start position and second end position 54, 56; however, it is interrupted by a collision object 76. If the measuring head 36 were now to be displaced along this measurement path 52, this would result in a collision and possibly a destruction of the measuring head 36. By way of example, the collision object 76 can be one of the aforementioned fastening elements 16. To avoid the collision, a new, collision-free measurement path 78 is preferably calculated by the novel method.

[0118] To adapt the measurement path from the data memory 50 to the actual start position and end position, it is advantageous to analyze the measurement path and, where possible, adapt all degrees of freedom of the coordinate measuring machine 100 (like in step 1400). This is illustrated in example fashion in FIG. 9. Table T1 shows an example measurement path, wherein the values of the degrees of freedom in each position traveled on a measurement path from a start position to an end position is depicted over time. Now, according to one example embodiment of the novel method, an analysis is carried out as to what degree of freedom changes at what point. By way of example, this corresponds to the optimization step 1600 and is illustrated in table T2, wherein the change in the degrees of freedom is determined starting from the start position. The changes are illustrated starting from the end position in table T3. Subsequently, the positions are altered starting from the start position in such a way that the values of the start position are used for as long as no change of the respective degree of freedom is specified. This is illustrated in tables T4-T6. The same is carried out starting from the end position; this is illustrated in tables T7 and T8. The procedure consequently describes an iterative process. Overall, an optimized measurement path is obtained (for example, after step 1600), by means of which unnecessary movements of the movement axes are avoided (see table T9).

[0119] A precondition for this method is that the “character” of the stored measurement path, which, as it were, represents the “template” for the modification, fits to the currently desired measurement path. By way of example, if the measurement path from the buffer contains no information items about a rotary movement (i.e., for example, a change between the degrees of freedom 4 to 6 in the respective header of the tables of FIG. 9), but the current start position and end position require such a rotary movement (for example, because the degree of freedom 4 changes between the start configuration and end configuration), the adaptation illustrated in FIG. 9 is insufficient; instead, it must be supplemented, for example manually, with a rotary movement. However, in such a case it is more advantageous as a matter of principle for a second measurement path to be recalculated.

[0120] 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