Mitutoyo Corporation

Andrew Patzwald

Benjamin K Jones

David William Sesko

Scott Allen Harsila

Scott Ellis Hemmings

Kim W Atherton

Casey Edward Emtman

Christopher Richard Hamner

Bjorn Erik Bertil Jansson

Jason Stuart Hartman

Stephen Gareth Alexander Smele

A scanning probe for a coordinate measuring machine with inductive position sensor signal gain control is provided. The scanning probe includes a stylus position detection portion with field generating and sensing coils, and for which corresponding output signals are indicative of a position of the probe tip of the stylus. Signal processing and control circuitry is configured to implement different operating regions, such as a central high gain operating region which corresponds to a central probe tip position range, as well as other lower gain operating regions, and for which transition operations may be performed for adjusting the gain. In various implementations, transition operations for adjusting a gain may include operations such as: adjusting power to a field generating coil configuration; adjusting a gain of a front end amplifier; altering characteristics of sensing coils; adjusting an input range of an analog to digital converter, etc.

Inductive position sensor signal gain control for coordinate measuring machine probe

A method is disclosed for operating a coordinate measuring machine (CMM) including a workpiece scanning probe. The method provides two different measurement sampling period durations in the scanning probe: a first shorter sampling duration provides a faster measurement having a first accuracy, a second longer sampling duration provides a slower measurement having a second (better) accuracy. The shorter sampling duration may be repeatedly interleaved or alternated with the longer sampling duration to provide sufficient accuracy and response time for motion control purposes during ongoing operation of the CMM. The longer sampling duration may provide high accuracy probe measurements to combine with position coordinate values from encoders located on motion axes of the CMM (outside the scanning probe) to provide high accuracy workpiece measurements at a desired frequency, or upon demand. A probe measurement timing subsystem may determine initiation times of the first and second sampling durations.

Method for operating a coordinate measuring machine

A method is disclosed for operating a coordinate measuring machine (CMM) including a CMM control system, a surface scanning probe that measures a workpiece surface by outputting probe workpiece measurements, and a probe measurement timing subsystem. The method comprises: operating the CMM control system to output a measurement synchronization trigger signal at predictable times; operating the probe measurement timing subsystem to determine a pre-trigger lead time that is a fraction of a current duration of a probe workpiece measurement sample period, to initiate a current instance of the probe measurement sample period at the pre-trigger lead time before a next predictable time of the measurement synchronization trigger signal; operating the CMM control system to latch a current set of CMM position coordinate values; and operating the surface scanning probe to output the current instance of the probe workpiece measurement in association with the current set of CMM position coordinate values.

A chromatic point sensor (CPS) system is provided, which compensates for potential errors due to input spectral profile intensity inconsistencies that arise when driving a CPS illumination source using different power levels. The CPS system includes an optical pen comprising a confocal optical path including a chromatically dispersive element and configured to focus different wavelengths at different distances proximate to a workpiece surface to be measured, an illumination source, and CPS electronics. The CPS electronics include: an illumination source control portion configured to drive the illumination source using different power levels; a CPS wavelength detector comprising a plurality of pixels distributed along a measurement axis of the CPS wavelength detector to provide output spectral profile data; and a power level spectral compensation portion configured to compensate the output spectral profile data to remove or reduce potential errors due to input spectral profile intensity inconsistencies that arise when driving the CPS illumination source using the different power levels.

Chromatic range sensor including dynamic intensity compensation function

A position encoder system (e.g., including a linear encoder) is configured to rapidly provide encoder position data in response to position trigger signals that are received from a host motion control system at predictable times (e.g., according to a preset frequency, etc.) A pre-trigger lead time is determined that is a fraction of a duration of a defined encoder position sample period. A current instance of the encoder position sample period is then initiated at the pre-trigger lead time before a next predictable time of the position trigger signal. A current position trigger signal is then received (e.g., near the middle of the current instance of the encoder position sample period) from the host motion control system. The average effective sample time of the current instance of the encoder position sample period coincides with the actual timing of the current position trigger signal within an allowed tolerance window.

Position encoder sample timing system

A method is provided for operating a chromatic range sensor (CRS) system, which may comprise a chromatic point sensor (CPS) system including an optical pen, to measure a low reflectivity surface. The CRS system may include a high sensitivity measurement mode in which it uses an unconventional low sampling rate or 'long' self-saturating exposure time, to measure the low reflectivity surface. The 'long' self-saturating exposure time may cause one or more detector pixels to self-saturate to at least a saturation threshold level, which prevents them from indicating a valid wavelength peak. Such pixels may define an invalid peak portion of a nominal total measurement range. The CRS may still detect a valid wavelength peak or height measurement, when the surface is located in a valid subset of the nominal total measurement range of the CRS system determined such that it excludes the invalid peak portion.

Chromatic range sensor including high sensitivity measurement mode

An interchangeable chromatic range sensor (CRS) probe for a coordinate measuring machine (CMM). The CRS probe is capable of being automatically connected to a CMM under program control. In one embodiment, in order to make the CRS probe compatible with a standard CMM auto exchange joint, all CRS measurement light transmitting and receiving elements (e.g., the light source, wavelength detector, optical pen, etc.) are included in the CRS probe assembly. The CRS probe assembly also includes an auto exchange joint element that is attachable through a standard auto exchange joint connection to a CMM. In one embodiment, in order to provide the required signals through the limited number of connections of the standard CMM auto exchange joint (e.g., 13 pins), a low voltage differential signaling (LVDS) serializer may be utilized for providing additional control and data signals on two signal lines.

Interchangeable chromatic range sensor probe for a coordinate measuring machine

A method for operating a chromatic range sensor (CRS) system to identify abnormal spectral profiles arising from light reflected from more than one portion of a workpiece surface is provided. The method comprises: providing a CRS system comprising: an optical element, a light source, and CRS electronics comprising a CRS wavelength detector; operating the CRS system to receive an output spectral profile from a measurement point on a workpiece surface and provide corresponding output spectral profile data; analyzing the output spectral profile data to provide a peak region asymmetry characterization; and providing a corresponding abnormality indicator if the peak region asymmetry characterization indicates that the peak region is abnormally asymmetric.

Method for identifying abnormal spectral profiles measured by a chromatic confocal range sensor

A method of categorizing the reliability of measurement data in a chromatic range sensor (e.g., an optical pen) which uses chromatically dispersed light to measure the distance to a surface. In one embodiment, the system performs a number of predetermined reliability checks which determine the reliability categories for the sets of measurement data. The reliability categories may be stored as metadata with the respective workpiece height measurements that are determined from the associated measurement data. The reliability categories may be reported to the user (e.g., as graphical reliability category indicators that accompany a graphical display of the measurement data). With these reliability categories, the user may make informed decisions regarding the measurement data (e.g., deciding to filter out data that is associated with certain reliability categories, making adjustments to the setup to achieve improved measurements, etc.).

Chromatic range sensor including measurement reliability characterization

An optical pen for use in a chromatic range sensor (CRS) may be used in a probe system for a coordinate measuring machine (CMM). The optical pen includes a confocal optical path, an interchangeable optics element, an optical pen base member, and a repeatable fast exchange mount. The confocal optical path includes a confocal aperture and a chromatically dispersive optics portion. The interchangeable optics element includes the chromatically dispersive optics portion. The optical pen base member includes an external mounting surface for mounting to an external reference frame. The repeatable fast exchange mount includes a first mating half located on the base member and a second mating half located on the interchangeable optics element. The repeatable fast exchange mount is configured to allow the base member to receive and hold the interchangeable optics element in a fixed relationship relative to the base member and the external reference frame.

Interchangeable optics configuration for a chromatic range sensor optical pen

A displacement measurement device has a detector area which is larger than the area of the beam spot reflected from the measurement surface. The detector area is made larger than the size of the beam spot on the detector area, in order to accommodate shifts in the location of the beam spot due to changes in the precise locations of the components of the displacement measurement device. The subset of pixels in the detector area having advantageous correlation characteristics, is then selected to perform the correlation calculation, thereby reducing data processing time requirements.

Displacement transducer with selectable detector area

An operator interface apparatus and associated methods may allow an operator to select and verify various operating parameters for an image correlation type of displacement transducer. A subset of pixels from a detector array or camera may be defined to participate in an image correlation displacement measurement operations.

Operator interface apparatus and method for displacement transducer with selectable detector area

An absolute position-sensing device is usable to measure the relative position of two elements. An absolute scale includes an integrated track extending along a measuring axis of the scale. The integrated track includes a plurality of code portions interleaved with, or embedded in, a plurality of periodic portions. Each periodic portion includes a plurality of periodically-placed incremental scale elements. Each code portion includes a plurality of code elements indicative of an absolute measurement value. The code elements are arranged in code element zones along the direction perpendicular to the motion axis, and are detectable by associated variations along the direction perpendicular to the motion axis. The offset of the periodically placed elements relative to a readhead of the device is combined with the absolute measurement value to determine an absolute position.

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Kirkland, WA, United States of America

Andrew Patzwald