Process for coordinate measurement on workpieces
First Claim
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1. A process for coordinate measurement on workpieces,using a coordinate measuring device with a probe head that produces a probe signal on making contact with a workpiece to be measured, said process comprising the steps of:
- contacting said workpiece with said probe head and producing said probe signal on making said contact;
differentiating said probe signal (TS) with respect to time to evaluate at least one time derivative (VS, AS, RS) of said probe signal to determine an exact moment of contact (tk) of said probe head with said workpiece and,setting a trigger threshold for said time derivative and assigning said exact moment of contact (tk) as a moment (t1, t2, t3) at which said time derivative (VS, AS, RS) of said probe signal (TS) reaches said trigger threshold.
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Abstract
A sensor in the probe head of a coordinate measuring device supplies probe signals. The first, and if necessary, higher time derivatives of the probe signals are formed and evaluated for the exact determination of the moment of contact of the probe head with a workpiece to be measured. During the evaluation, the time course of the differentiated signals is examined by means of automatically generated trigger thresholds.
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Citations
12 Claims
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1. A process for coordinate measurement on workpieces,
using a coordinate measuring device with a probe head that produces a probe signal on making contact with a workpiece to be measured, said process comprising the steps of: -
contacting said workpiece with said probe head and producing said probe signal on making said contact; differentiating said probe signal (TS) with respect to time to evaluate at least one time derivative (VS, AS, RS) of said probe signal to determine an exact moment of contact (tk) of said probe head with said workpiece and, setting a trigger threshold for said time derivative and assigning said exact moment of contact (tk) as a moment (t1, t2, t3) at which said time derivative (VS, AS, RS) of said probe signal (TS) reaches said trigger threshold. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. A coordinate measuring device with a probe head that produces a probe signal (TS) on contact with a workpiece to be measured, comprising:
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a first memory unit capable of storing a time course of said probe signal (TS) that is fed to said first memory unit, a second memory unit capable of storing length measurement values (x,y,z) for a position of said probe head at least for a time interval that includes an exact moment of contact (tk) of said probe head with said workpiece, and an evaluation unit to which said first memory unit and said second memory unit are connected, which is capable of determining said exact moment of contact (tk) by differentiating said probe signal (TS) and establishing whether an amplitude of said differentiated probe signal (VS, AS, RS) has reached an adjustable threshold and assigning said exact moment of contact as a moment at which said amplitude reaches said adjustable threshold.
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Specification