Mitutoyo Corporation

Mituoyo Corporation

Nobuhiro Ishikawa

Hideyuki Nakagawa

Satoshi Koga

Akinori Saito

Yutaka Kuriyama

Shingo Kiyotani

Nobuhisa Nishioki

Hiroyuki Kanamori

Motonori Ogihara

Kazuhiko Hidaka

Takashi Noda

Kiyokazu Okamoto

Hirohisa Handa

Kunitoshi Nishimura

As a former correction step, a coordinate correction method includes: a step of setting a measuring probe in a drive mechanism; a step of restraining a measurement tip; a step of acquiring a moving amount and a probe output; and a step of generating a former correction matrix including linear correction elements and non-linear correction elements. As a latter correction step, the coordinate correction method includes: a step of setting a measuring probe in a drive mechanism; a step of restraining a measurement tip; a step of acquiring a moving amount and a probe output; a step of generating an intermediate correction matrix including linear correction elements for correcting the probe output; and a step of correcting the probe output with a latter correction matrix. Consequently, correction can be simplified while allowing for correction of a non-linear error of the probe output supplied from the measuring probe.

Coordinate correction method and coordinate measuring machine

A processing device includes: a coordinate acquisition unit that acquires a moving amount of a measuring probe and a probe output; a matrix generation unit that generates a correction matrix including linear correction elements and non-linear correction elements; and a probe output correction unit that corrects the probe output with the correction matrix. The coordinate acquisition unit acquires the moving amount and the probe output of the measuring probe in each of measurement points in a quantity larger than or equal to the sum of the number of the linear correction elements and the number of the non-linear correction elements. Consequently, a non-linear error of the probe output supplied from the measuring probe can be corrected, and thus shape coordinates of an object to be measured can be obtained with high accuracy.

Coordinate measuring machine and coordinate correction method

A processing device includes: a pushing drive mechanism control unit that brings a measurement tip into contact with a surface of a calibration artifact at a single point in each of five directions are all normal directions to the surface of the calibration artifact; a scanning drive mechanism control unit that reciprocates the measurement tip on the surface of the calibration artifact on each of three planes perpendicular to one another; a coordinate acquisition unit that acquires a moving amount and a probe output of a measuring probe; a matrix generation unit that generates a correction matrix; and a probe output correction unit that corrects the probe output with the correction matrix. This enables an improvement in asymmetric probe characteristics of the probe output, which is outputted from the measuring probe, in a particular plane. Thus, shape coordinates of an object to be measured can be obtained with high accuracy.

A measuring probe includes two supporting members, each having a rotationally symmetric shape and allowing for an attitude change of a stylus, in an axial direction of a probe housing. Four detection elements are disposed at fourfold symmetric positions in one of the two supporting members that includes four deformable arm parts. A signal processing circuit includes a first processing part that processes outputs of the detection elements to output three displacement signals representing displacement components of a contact part in mutually perpendicular three directions, respectively. The measuring probe capable of reducing measurement directional dependency of sensitivity with a simple configuration while maintaining high sensitivity is thus provided.

Measuring probe

A measuring probe includes: a stylus having a contact part to be brought into contact with an object to be measured; a probe housing capable of supporting the stylus on an axial center; and a detection element capable of detecting a movement of the contact part. The measuring probe further includes: two supporting members disposed in an axial direction of the probe housing, the supporting member allowing for an attitude change of the stylus; and a coupling shaft for coupling the two supporting members together. The detection element is disposed in one of the two supporting members that is farthest away from a rotational center position of rotation generated in the stylus when a measuring force is applied to the contact part from a direction perpendicular to the axial direction, to detect a strain amount of the one of the two supporting members.

A contact detector circuit that detects a change in a DC sensor signal based on a change in a physical amount to be detected includes: a reference signal generation circuit that generates a reference signal based on the DC sensor signal; a trigger signal output circuit that compares the DC sensor signal with the reference signal and outputs a trigger signal based on a result of the comparison; and a sampling-and-holding circuit that holds the reference signal when the trigger signal is started to be outputted and outputs the held reference signal to the trigger signal output circuit while the trigger signal is outputted. The trigger signal output circuit uses the reference signal outputted by the sampling-and-holding circuit for the comparison with the DC sensor signal while the trigger signal is outputted.

Sensor signal contact detector circuit

A first correction component calculation processing unit calculates diagonal components of a correction matrix based on first and second detection values. The first and second detection values are obtained by measurement in which a calibration reference body and the probe are moved relatively to each other in a normal direction on a surface of the calibration reference body so as to bring a measurement tip into contact with the surface of the calibration reference body at one point. A second correction component calculation processing unit calculates non-diagonal components of the correction matrix based on third and fourth detection values. The third and fourth detection values are obtained by scanning measurement using the measurement tip on the surface of the calibration reference body while maintaining a constant relative distance between the center of the measurement tip and a reference point or a reference line of the calibration reference body.

Coordinate measuring machine and method for calculating correction matrix by coordinate measuring machine

A form measuring machine includes: a scanning probe including a stylus with a tip ball and a probe body attached with the stylus; a movable slider supporting the scanning probe; a scale detecting a slider displacement of the slider; a tip ball displacement detector detecting a tip ball displacement of the tip ball; and an arithmetic unit calculating a measurement value based on the slider displacement, the tip ball displacement and a correction filter and comprising a correction filter setting section that: calculates a correction matrix diagonal component from the slider displacement and the tip ball displacement detected by calibration of the scanning probe; and calculates a correction factor of the correction filter from the correction matrix diagonal component to set the correction filter.

Form measuring machine and form measuring method

In a shape measuring apparatus having a scanning probe to perform scanning measurement using a tip ball provided at an end of a stylus with the tip ball being in contact with an object to be measured, a tip ball displacement detector detects a displacement of the tip ball of the scanning probe, a displacement of a moving mechanism that relatively moves the object to be measured and the scanning probe is detected, and an angle formed by a contact direction of the tip ball with the object to be measured and an axial direction of the stylus is calculated. The displacement of the tip ball that is detected by the tip ball displacement detector is corrected on the basis of the angle, and a corrected value of the displacement is outputted. The corrected value is added to the displacement of the moving mechanism to calculate a measurement value.

Method of correcting measurement error of shape measuring apparatus, and shape measuring apparatus

A calculator includes a first filter, a second filter, and an adding device. The first filter outputs, as a first corrected value, a value in which displacement of a displacement table detected by a scale has been corrected based on first frequency transfer characteristics from a scale to a measured object station. The second filter outputs, as a second corrected value, a value in which the first corrected value is corrected based on second frequency transfer characteristics from a ball tip to a ball tip displacement detector. The adding device adds the second corrected value and displacement of the ball tip detected by the ball tip displacement detector to calculate a measured value.

Shape measuring apparatus and shape measurement error correction method

A shape measuring machine includes a slider that supports a scanning probe including a tip sphere. A scale unit detects a displacement of the slider. A tip sphere displacement detection unit detects a displacement of the tip sphere. A calculation unit includes a correction filter and an adder, and calculates a measurement value from the displacements of the slider and the tip sphere. The correction filter outputs a correction value that is obtained by correcting the displacement of the tip sphere detected by the tip sphere displacement detection unit based on an inverse characteristic of a frequency transfer characteristic from the scale unit to the tip sphere. The adder calculates the measurement value by adding the displacement of the slider detected by the scale unit and the correction value.

Shape measuring machine and method of correcting shape measurement error

A shape measuring machine includes a slider that supports a scanning probe. A scale unit detects a displacement of the slider. A tip sphere displacement detection unit detects a displacement of the tip sphere. A calculation unit includes a correction filter including a first and second filters and an adder, and calculates a measurement value from the displacements of the slider and the tip sphere. The first filter corrects the displacement of the slider based on a frequency transfer characteristic from the scale unit to the tip of the slider. The second filter outputs a value that is obtained by correcting a value corrected by the first filter based on a frequency transfer characteristic from the tip of the slider to the tip sphere as the correction value. The adder outputs a measurement value obtained by adding the correction value and the displacement of the tip sphere.

A line image sensor including a light receiving plane on which two or more straight rows of pixels are disposed, the straight rows of pixels capturing images of regular fringes generated from light reflected from an irradiated body in accordance with the amount of light received by each pixel; at least two rows of pixels acquiring images of linear fringes crossing at right angles in two directions among the fringe projected onto the light receiving plane.

Image sensor, attitude detector, contact probe, and multi-sensing probe

A coordinate measuring machine includes: a probe provided with a measurement piece; a moving mechanism that effects a scanning movement of the probe; and a host computer for controlling the moving mechanism. The host computer includes a displacement acquiring unit for acquiring a displacement of the moving mechanism and a measurement value calculating unit for calculating a measurement value. The measurement value calculating unit includes a correction-amount calculating unit for calculating a correction amount for correcting a position error of the measurement piece and a correcting unit for correcting the position error of the measurement piece based on the displacement of the moving mechanism and the correction amount. The correction-amount calculating unit calculates a translation-correction amount for correcting a translation error of the probe at a reference point on the probe and a rotation-correction amount for correcting a rotation error of the probe according to a rotation angle of the probe around the reference point and a length of the probe from the reference point to the measurement piece.

Coordinate measuring machine

A coordinate measuring machine includes: a probe that has a contact point capable of movement within a predetermined range; a movement mechanism for moving the probe; and a controller for controlling the movement mechanism. The controller has a measurement value calculating unit for calculating a position of the contact point based on a displacement of the movement mechanism and a displacement of the probe. The measurement value calculating unit includes: a correction parameter calculator for calculating a correction parameter for correcting the displacement of the probe based on a measurement condition in measuring an object; a corrector for correcting the displacement of the probe based on the correction parameter; and a displacement synthesizing unit that synthesizes the displacement of the movement mechanism and the displacement of the probe corrected by the corrector to calculate the position of the contact point.

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Ibaraki, Japan

Nobuhiro Ishikawa