Method and device for determining actual dimensional properties of a measured object

A device for determining actual dimensional properties of a measured object having a plurality of geometric elements, the device comprising:

• a workpiece receptacle for holding the measured object;
• a measuring head that is displaceable relative to the workpiece receptacle and configured to record measurement values that represent a position of at least one measurement point on the measured object;
• an evaluation and control unit that displaces the measuring head relative to the workpiece receptacle depending on a defined measurement sequence;
• and
• an interface for supplying demand data that represent demand properties for the plurality of geometric elements of the measured object,
• wherein:
• the demand properties comprise acceptable manufacturing tolerances for the geometric elements,
• the evaluation and control unit is configured to generate the defined measurement sequence,
• the defined measurement sequence defines movements of the measuring head relative to the measured object and defines measurement values to be recorded at defined measuring head positions relative to the measured object,
• the evaluation and control unit is configured to:
• select defined geometric elements from the plurality of geometric elements based on the demand data;
• determine test features relating to the defined geometric elements based on the demand data;
• determine control commands for controlling the measuring head relative to the defined geometric elements based on the test features;
• and
• control the measuring head depending on the control commands in order to record individual measurement values on the measured object and to determine first numerical values depending on the individual measurement values,
• the first numerical values represent actual dimensional properties of the measured object,
• the actual dimensional properties correspond to the test features,
• the evaluation and control unit is further configured to, prior to commencing the defined measurement sequence and recording the individual measurement values:
• generate a first measurement sequence that defines first control commands for controlling the measuring head relative to the measured object based on the test features;
• ascertain defined measurement uncertainty based on the first control commands;
• modify the first measurement sequence before recording the individual measurement values in order to obtain a second measurement sequence with second control commands, wherein the second control commands at least partly differ from the first control commands,
• the evaluation and control unit is configured to use the second control commands according to the second measurement sequence to control the measuring head for recording the individual measurement values, and
• the evaluation and control unit is configured to select the second control commands in such a way that:
• the numerical values each have a defined measurement uncertainty that is smaller by a defined absolute value than the acceptable manufacturing tolerances for the geometric elements and
• the defined measurement uncertainty for at least one of the test features is increased while the defined measurement uncertainty for at least one other test feature is one of maintained and reduced.

A method for determining actual dimensional properties of a measured object having a plurality of geometric elements, the method comprising the following steps:

• providing a coordinate measuring machine having a measuring head for recording measurement values representing a position of at least one measurement point on the measured object;
• providing demand data representing demand properties for the plurality of geometric elements of the measured object, wherein the demand properties comprise acceptable manufacturing tolerances for the geometric elements;
• generating, in a computer-assisted manner, a measurement sequence that defines movements of the measuring head relative to the measured object and that defines measurement values to be recorded at defined measuring head positions relative to the measured object;
• controlling the measuring head based on control commands and recording individual measurement values on the measured object;
• and
• determining numerical values based on the individual measurement values,
• wherein:
• the numerical values represent actual dimensional properties of the measured object that correspond to a plurality of test features,
• generating the measurement sequence includes, prior to performing the controlling:
• selecting defined geometric elements from the plurality of geometric elements;
• based on the demand data, determining the plurality of test features relating to the defined geometric elements;
• generating a first measurement sequence that defines first control commands;
• determining defined measurement uncertainty according to the first control commands;
• and
• modifying the first measurement sequence in order to obtain a second measurement sequence with second control commands, wherein the second control commands at least partially differ from the first control commands,
• the second control commands are used for controlling the measuring head for recording the individual measurement, and
• the modifying includes selecting the second control commands in such a way that:
• the numerical values each have a defined measurement uncertainty that is smaller by a defined absolute value than the acceptable manufacturing tolerances for the geometric elements and
• respective individual measurement uncertainties are obtained for the plurality of test features.

A non-transitory storage medium encoded with a computer program that, when executed by a computer processor, causes a computer to perform the following steps:

• obtaining demand data representing demand properties for a plurality of geometric elements of a measured object, wherein the demand properties comprise acceptable manufacturing tolerances for the geometric elements;
• generating, in a computer-assisted manner, a measurement sequence that defines movements of a measuring head of a coordinate measuring machine relative to the measured object and that defines measurement values to be recorded at defined measuring head positions relative to the measured object;
• recording individual measurement values on the measured object by controlling the measuring head depending on control commands of the measurement sequence;
• and
• determining numerical values depending on the individual measurement values,
• wherein:
• the numerical values represent actual dimensional properties of the measured object that correspond to test features,
• the generating includes, prior to the recording,
• selecting defined geometric elements from the plurality of geometric elements;
• determining the test features relating to the defined geometric elements based on the demand data;
• based on the test features, generating a first measurement sequence that defines first control commands;
• ascertaining defined measurement uncertainty is ascertained depending on the first control commands;
• and
• modifying the first measurement sequence based on the ascertained measurement uncertainty in order to obtain a second measurement sequence with second control commands, wherein the second control commands at least partially differ from the first control commands,
• the control commands for recording the individual measurement values are the second control commands, and
• the modifying includes selecting the second control commands in such a way that:
• the numerical values each have a defined measurement uncertainty that is smaller by a defined absolute value than the acceptable manufacturing tolerances for the geometric elements and
• the defined measurement uncertainty is increased for at least one of the test features while the defined measurement uncertainty for at least one other test feature is one of maintained and reduced.