Renishaw Plc

David Sven Wallace

Geoffrey McFarland

Martin Simon Rees

David R McMurtry

David Jones

Peter Hajdukiewicz

Andrew Geoffrey Butter

Peter G Lloyd

Jean-Louis Grzesiak

James L Chase

Stephen Paul Hunter

Ian William McLean

Richard Neil Danbury

David Roberts Mcmurtry

Geoffrey Mcfarland

James Lancelot Chase

Peter George Lloyd

A surface sensing device is mounted on an articulating probe head of a coordinate measuring machine. The device includes an elongate probe holder which is rotatable about an axis. An elongate sensing module includes a surface finish or surface roughness probe with a stylus tip. This is connected to the probe holder via an adjustable knuckle joint. To determine the geometry of the surface sensing device, including the tip normal and drag vector of the stylus tip, the orientations of the probe holder and the sensing module are determined by probing points which are spaced along their lengths, using a separate probe.

Method of calibrating a surface sensing device, corresponding calibrating program for a control computer and corresponding calibration kit

A method of determining sub-divisional error of an encoder apparatus, which is configured to measure relative position of relatively moveable parts of an apparatus on which an inspection device for inspecting an artefact is mounted, includes causing the inspection device to inspect a feature so as to obtain measurements of a surface of the feature by relatively moving the relatively moveable parts of the apparatus. The method also includes using the measurements of the surface of the feature obtained by the inspection device during the inspection of the feature to determine the sub-divisional error of the encoder apparatus.

Method of determining sub-divisional error of an encoder apparatus configured to measure relative position of relatively moveable parts

A method of calibrating a contact probe having a contact element includes measuring with the contact probe a first geometric property of a calibrated artifact and a second geometric property of the or a further calibrated artifact. The first and second geometric properties are such that a deviation between a measured value and the expected value, resulting from a difference between an effective diameter of the contact element and an assumed diameter used for determining the measured value, has the opposite sign for each of the first and second geometric properties. The method further includes identifying a difference in the effective diameter of the contact element from the assumed diameter including comparing deviations of the measured value to the expected value for each of the first and second geometric properties to determine whether there is a difference in the deviations.

Calibration of a contact probe

A method of locating a feature of an object in which the method includes bringing a stylus of a contact probe mounted on a positioning apparatus into contact with the object to obtain at least first and second measurements of the object. Each which the measurements gives rise to a range of possible points of contact between the object and a part of the stylus along its length and therefore inherently containing uncertainty in the location of the object along said length. The at least first and second measurements are used to reduce the extent of said uncertainty which includes using stylus orientation related information associated with the at least first and second measurements.

Measurement method

A method of operating a coordinate positioning apparatus having a surface sensor that is rotatable about at least a first axis. The method comprises obtaining a first measurement with the surface sensor at a first angular orientation and obtaining a at least a second measurement with the surface sensor at a second angular orientation. The first and second angular orientations are different to each other such that any offset of the surface sensor from an expected position will have at least a partially opposing affect on the first and second measurements. The method then compensates and/or establishes for the offset using the first and second measurements.

Surface sensor offset

A method and apparatus for controlling or programming a measurement path for a probe mounted on a coordinate positioning apparatus (e.g. an articulating probe head mounted on a CMM) which enables both the position of the probe tip and the orientation of the probe to be varied. In a first mode, the position of the probe tip is adjusted. In a second mode the orientation of the probe is adjusted, while keeping the location of the probe tip unchanged. This may be achieved either online on the coordinate positioning apparatus or offline in software.

Apparatus and method for controlling or programming a measurement routine

A method for orienting a surface sensing device (SSD) uses an apparatus having a support attachable to a moveable arm of a machine, such as a coordinate measuring apparatus. The support includes a first member rotatable about a first axis of rotation and a SSD for sensing the surface of a workpiece; the SSD is releasably connectable to the first member for rotation therewith. The method includes the steps of disconnecting a SSD from a support, the SSD being connected to the support in a first orientation; rotating one of the SSD and the support relative to the other of the SSD and the support and reconnecting the SSD and the support into a second orientation. An apparatus for orienting a surface sensing device is further described.

Surface sensing device

Disclosed is a method of moving an articulating mechanism () for a measuring device, comprising the steps of: releasing two bodies (a,b) which form the articulating mechanism allowing relative movement thereof; moving one of the bodies with respect to the other until a desired position is reached; and re-constraining the two bodies so they are relatively fixed, perhaps as part of a locking process, characterised in that relative movement prior to re-constraining at the desired position occurs under particular conditions. The particular conditions including moving from the same direction; and stopping, slowing down or maintaining the condition at a position adjacent to the desired position. Also disclosed is a method of positioning an articulating mechanism () for a measuring device which is controlled by a potentiometer and a controller () for a measuring device.

Articulating device

An apparatus for measuring a surface of a workpiece is described. The apparatus comprises a support, attachable to the moveable arm of a machine, such as a coordinate positioning machine, and rotatable about first and second axes of rotation, the axes driven by first and second motors respectively. The apparatus additionally comprises a surface sensing device for sensing the surface of a workpiece, rotatable about a third axis of rotation. This third axis of rotation is alignable with the first axis of rotation, and when aligned, rotation of the support relative to the surface sensing device is actuatable by the first motor. A method for using an apparatus for measuring a surface of a workpiece is also described.

A method for planning the trajectory of an apparatus, such as an articulating probe head, mounted on a coordinate positioning apparatus, such as a CMM. It is determined whether for a given trajectory, the angular velocity or acceleration of the apparatus about a rotational axis of the apparatus will exceed a predetermined threshold. If so, parameters are adjusted so that the angular velocity or acceleration do not exceed the threshold.

Method of path planning

Disclosed is a method of moving an articulating mechanism () for a measuring device, comprising the steps of: releasing two bodies () which form the articulating mechanism allowing relative movement thereof; moving one of the bodies with respect to the other until a desired position is reached; and re-constraining the two bodies so they are relatively fixed, perhaps as part of a locking process, characterised in that relative movement prior to re-constraining at the desired position occurs under particular conditions. The particular conditions including moving from the same direction; and stopping, slowing down or maintaining the condition at a position adjacent to the desired position. Also disclosed is a method of positioning an articulating mechanism () for a measuring device which is controlled by a potentiometer and a controller () for a measuring device.

A method of calibrating an analogue probe () having a stylus () with a workpiece-contacting tip () or a non-contact probe (). A calibration artefact such as a calibration sphere () is mounted on a coordinate measuring machine (CMM) (). The probe () is mounted on an arm () of the CMM and the probe is moved along a path whilst continually scanning the surface of the calibration artefact such that the probe is exercised throughout its working range. For an analogue probe () having a workpiece-contacting stylus (), the path is such that the deflection of the stylus varies along the path. For a non-contact probe () the path is such that there is variation of the radial distance between the path and the calibration artefact. The probe path may comprise a path parallel to a chord of the calibration sphere or a curved, e.g. a sinusoidal, path.

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Nympsfield, United Kingdom

David Sven Wallace