Method and machine for determining a space coordinate of a measurement point on a measurement object
First Claim
1. A method for determining at least one space coordinate of a measurement point on a measurement object using a coordinate measuring machine (“
- CMM”
) having a probe head arranged on a displacement mechanism comprising first and second movable supports for controling movement of the probe head along at least a first axis, comprising the steps of;
conducting a calibration run of the CMM and obtaining measurement values of the displacement position of each of said first and second movable supports at a plurality of defined positions of said probe head,storing in a memory a plurality of static difference values determined in accordance with the difference in the respective measurement values for said first and second movable supports at each of said plurality of defined positions,subsequently conducting a measurement run of the CMM by approaching the measuring point with the probe head,determining a first displacement position of the first movable support and determining a second displacement position of the second movable support,determining an actual difference value between the first and the second displacement positions,determining from the static difference values stored in said memory a static difference value which represents a static difference between the first and the second displacement positions,subtracting the static difference value from the actual difference in order to obtain a dynamic difference value,correcting the first displacement position using the dynamic difference value in order to obtain a pre-corrected displacement position, andsubsequently correcting the pre-corrected displacement position by using the static difference value,thereby determining the space coordinate of the measurement point.
1 Assignment
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Accused Products
Abstract
A measurement point is approached with a probe head arranged on a displacement mechanism having at least two supports. An actual difference value between the displacement positions of a first and a second support is determined. A static difference value representing is provided and subtracted from the actual difference, in order to obtain a dynamic difference value representing a static difference between the first and the second displacement positions is subtracted from the actual difference value in order to obtain a dynamic difference value. The space coordinate of the measurement point is determined as a function of the dynamic difference value.
16 Citations
15 Claims
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1. A method for determining at least one space coordinate of a measurement point on a measurement object using a coordinate measuring machine (“
- CMM”
) having a probe head arranged on a displacement mechanism comprising first and second movable supports for controling movement of the probe head along at least a first axis, comprising the steps of;conducting a calibration run of the CMM and obtaining measurement values of the displacement position of each of said first and second movable supports at a plurality of defined positions of said probe head, storing in a memory a plurality of static difference values determined in accordance with the difference in the respective measurement values for said first and second movable supports at each of said plurality of defined positions, subsequently conducting a measurement run of the CMM by approaching the measuring point with the probe head, determining a first displacement position of the first movable support and determining a second displacement position of the second movable support, determining an actual difference value between the first and the second displacement positions, determining from the static difference values stored in said memory a static difference value which represents a static difference between the first and the second displacement positions, subtracting the static difference value from the actual difference in order to obtain a dynamic difference value, correcting the first displacement position using the dynamic difference value in order to obtain a pre-corrected displacement position, and subsequently correcting the pre-corrected displacement position by using the static difference value, thereby determining the space coordinate of the measurement point. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
- CMM”
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13. A coordinate measuring machine for determining during a measurement run at least one space coordinate of a measurement point on a measurement object, comprising
a displacement mechanism having a first and a second movable support, a probe head arranged on the displacement mechanism for approaching the measuring point, a first and a second measuring instrument for determining a first displacement position of the first movable support and a second displacement position of the second movable support, respectively, an actual difference formation unit for determining an actual difference value between the first and second displacement positions, a memory for permanently storing and providing a static difference value representing a static difference between the first and second displacement positions, said static difference value being determined by means of a previously conducted calibration run and then stored in the memory, and a calculation unit for determining the space coordinate of the measurement point, the calculation unit comprising a subtractor for subtracting the static difference value from the actual difference value in order to obtain a dynamic difference value, and further configured to correct the first displacement position using the dynamic difference value in order to obtain a pre-corrected displacement position, and subsequently correct the pre-corrected displacement position by using the static difference value, thereby determining the space coordinate of the measurement point.
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14. A computer program product comprising program code configured for carrying out a method, when executed on a processor of a coordinate measuring machine, comprising the following steps:
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approaching the measuring point with a probe head arranged on a displacement mechanism which comprises a first and a second movable support, determining a first displacement position of the first support and determining a second displacement position of the second support, determining an actual difference value between the first and the second displacement positions, receiving a static difference value which represents a static difference between the first and the second displacement positions, said static difference value being determined by means of a previously conducted calibration run and then stored in a memory, subtracting the static difference value from the actual difference value in order to obtain a dynamic difference value, correcting the first displacement position using the dynamic difference value in order to obtain a pre-corrected displacement position, and subsequently correcting the pre-corrected displacement position by using the static difference value, thereby determining the space coordinate of the measurement point.
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15. A method for determining at least one space coordinate of a measurement point on a measurement object, comprising the steps of:
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approaching the measuring point with a probe head arranged on a displacement mechanism which comprises a first and a second movable support, determining a first displacement position of the first support and determining a second displacement position of the second support, determining an actual difference value between the first and the second displacement positions, providing a static difference value which represents a static difference between the first and the second displacement positions, subtracting the static difference value from the actual difference value in order to obtain a dynamic difference value, and determining the space coordinate of the measurement point as a function of the dynamic difference value and the static difference value, wherein the measurement point is approached by means of at least two drives, a first drive moving the first support, and a second drive mechanically independent of said first drive for moving the second support, and further wherein the first and second drives are actuated by a common electronic regulator which receives the dynamic difference value as an input quantity.
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Specification