Carl-zeiss-stiftung

Carl-zeiss-stiftung, Heidenheim/brenz

Gunter Grupp

Ralf Bernhardt

Otto Ruck

Wolfgang Wiedmann

Karl-Hermann Breyer

Anton Fuchs

Berndt Kammleiter

Eugen Aubele

Peter Ebersbach

Eugen Trapet

Uwe Wiegand

The invention is directed to a method which is provided for controlling coordinate measuring apparatus wherein a probe head (2) is moved and has a movably attached probe unit (24) attached thereto. The probe unit (24) is charged with a measurement force Fmeas relative to the probe head (2). The measurement force Fmeas operates against the mass inertial forces Fzp which occur because of acceleration of the probe. The measurement force Fmeas is comprised of a desired measurement force Fdes and a corrective measurement force Fcorr. The desired measurement force Fdes is constant in magnitude and is directed perpendicularly to the surface of the workpiece (15) to be measured. The corrective measurement force Fcorr at least partially compensates for the mass inertial forces (Ftr, Fzp) which occur because of the acceleration of the probe unit (24).

Coordinate measuring apparatus and method for controlling the same

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.

Process for coordinate measurement on workpieces

A coordinate measuring apparatus for measuring a workpiece with a probe head having a probe element for contacting the workpiece. The coordinate measuring apparatus includes: a plurality of sensors with each sensor supplying a signal indicative of a coordinate measurement position and a processing unit. An interface device between the plurality of sensors and the processing unit receives the signals and supplies a plurality of output signals to the processing unit representing respective position measurement values at any given instant of time. The processing unit includes at least one smoothing function block for continuously receiving a portion of the position measurement values. The smoothing function block is adapted to determine a final position measurement value (X.sub.E, Y.sub.E, Z.sub.E or R.sub.E) of the contact point of the probe element on the workpiece in a defined standstill of the apparatus by averaging a defined number of the received position measurement values to form a mean value. The processing unit further includes a function block for triggering the averaging before the apparatus reaches standstill and continuing the averaging until standstill is determined.

Coordinate measuring apparatus wherein the measuring time is optimized

The method is used to determine the elastic bending behavior of coordinate measuring machines as a result of the measuring force and the position of measuring slides in the measuring range of the machine. Correction values are determined, which are used to compensate for measuring errors caused by machine bending. The correction values are a function of the position of the measuring slides and on the measuring force between the probe of the coordinate measuring machine and workpieces within the measuring range, and are established and stored for several positions. The method can be combined very advantageously with known methods for the correction of guideway errors, which were developed on the basis of a rigid model, and with methods for the dynamic correction of machine deviations caused by vibration of machine components.

Method for coordinate measurement on workpieces adjusted for bending of

Measured position data (Px, Py, Pz) are combined with stored correction values (DB) describing the elastic bending behavior of a coordinate measuring machine in that parameters characterizing the bending behavior are determined for several positions of the probe of the machine within the measuring range (30) of the machine, the acceleration-dependent components of these parameters are determined and stored in the form of correction values (c11, c22) which describe the bending behavior of the coordinate measuring machine as a function of the position (Px, Py, Pz) of measuring slides (22, 23, 24), and at least of the acceleration (ax, ay, az) of the measuring slides introduced via the drives, the correction values being combined with measured position data (Px, Py, Pz) of the coordinate measuring machine in subsequent coordinate measurements on workpieces.

Method for correcting coordinate measurement on workpieces based on

A computer-operated coordinate-measurement machine has two length-measurement systems arranged in parallel for measuring the longitudinal displacement of a probe carried by the portal (3-5) of the machine, and these two length-measurement systems (13, 14) may belong to different precision classes. A computer-associated device (16) forms an absolute position-measurement value (Ym) from length-measurement signals of the more precise measurement system (13) and said device forms a dynamic measurement or instantaneous deviation value (Ys-Ym) from the difference between length-measurement signals of the respective systems (13, 14). The computer of the machine calculates the effective instantaneous position (Ym+.DELTA.y) of the probe (9a, b, c) borne by the portal (3-5), using the instantaneous value of the transverse position of the probe on the portal, in conjunction with the absolute measurement value (Ym) and the dynamic measurement value (Ys-Ym).

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Bohmenkirch, Germany

Gunter Grupp