Three-dimensional touch probe using three fibre optic displacement sensors

AbstractThis study focuses on 3 Hz fatigue load testing of a reinforced concrete beam in laboratory conditions. Three-dimensional (3D) image time series of the beam’s top surface were captured with the Microsoft time-of-flight Kinect 2.0 sensor. To estimate the beam deflection, the imagery was first segmented to extract the top surface of the beam. The centre line was then modeled using third-order B-splines. The deflection of the beam as a function of time was estimated from the modeled centre line and, following past practice, also at several witness plates attached to the side of the beam. Subsequent correlation of the peak displacement with the applied loading cycles permitted estimation of fatigue in the beam. The accuracy of the deflections was evaluated by comparison with the measurements obtained using a Keyence LK-G407 laser displacement sensors. The results indicate that the deflections can be recovered with sub-millimetre accuracy using the centreline profile modelling method.

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Non-Contact R-Test for Error Calibration of Five-Axis Machine Tools

ASME/ISCIE 2012 International Symposium on Flexible Automation ◽

10.1115/isfa2012-7211 ◽

2012 ◽

Author(s):

Soichi Ibaraki ◽

Cefu Hong

Keyword(s):

Machine Tools ◽

Three Dimensional ◽

Target Surface ◽

Test Device ◽

Contact Type ◽

Sphere Center ◽

Displacement Sensors ◽

New Instrument ◽

Error Calibration ◽

Five Axis

The R-test is a new instrument to measure three-dimensional displacement of a precision sphere attached to a spindle relative to a work table by using three displacement sensors. Its application to error calibration for five-axis machine tools has been studied in both academia and industry. For the simplicity in calculating the sphere center displacement, all conventional R-test devices use contact-type displacement sensors with a flat-ended probe. Conventional contact-type R-test may be potentially subject to the influence of the friction or the dynamics of supporting spring in displacement sensors particularly in dynamic measurement. This paper proposes a non-contact R-test with laser displacement sensors. A new algorithm was proposed to estimate the three-dimensional displacement of sphere center by using laser displacement sensors, It compensates the measurement uncertainty caused by the inclination of the target surface. Experimental case studies are presented to evaluate its measurement performance by comparing with the conventional contact-type R-test device.

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Dynamic Displacement of an Aluminum Frame Using Close Range Photogrammetry

Buildings ◽

10.3390/buildings9080176 ◽

2019 ◽

Vol 9 (8) ◽

pp. 176 ◽

Cited By ~ 1

Author(s):

Setareh Ghaychi Afrouz ◽

Mohammad Reza Razavi ◽

Ashkan Pourkand ◽

Claudia Mara Dias Wilson

Keyword(s):

Numerical Models ◽

Three Dimensional ◽

Contact Method ◽

Dynamic Displacement ◽

Close Range Photogrammetry ◽

Displacement Sensors ◽

Laser Scanners ◽

Close Range ◽

Story Building ◽

Unconventional Methods

Dynamic displacement measurement of objects can be challenging due to the limitations of conventional methods and pricey instrumentation of unconventional methods, such as laser scanners. In this research, Close Range Photogrammetry (CRP) is used as an affordable non-contact method to measure 3D dynamic displacements. It is proposed as a reliable alternative to traditional dynamic deformation measurement methods such as displacement sensors or accelerometers. For this purpose, dynamic displacements of a three-dimensional one-story building frame model on a one-dimensional shake table are determined by using the traditional method of attached accelerometer and CRP. The results of the CRP method are compared with the results of the traditional methods as well as numerical models. The results show a good agreement which evidences the reliability of the CRP with regular cameras.

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R-Test Analysis Software for Error Calibration of Five-Axis Machine Tools – Application to a Five-Axis Machine Tool with Two Rotary Axes on the Tool Side –

International Journal of Automation Technology ◽

10.20965/ijat.2015.p0387 ◽

2015 ◽

Vol 9 (4) ◽

pp. 387-395 ◽

Cited By ~ 14

Author(s):

Soichi Ibaraki ◽

◽

Yu Nagai ◽

Hisashi Otsubo ◽

Yasutaka Sakai ◽

...

Keyword(s):

Machine Tool ◽

Machine Tools ◽

Three Dimensional ◽

Geometric Error ◽

Test Analysis ◽

Rotary Axes ◽

Rotary Axis ◽

Displacement Sensors ◽

Error Calibration ◽

Five Axis

The R-test measures the three-dimensional displacement of a precision sphere, attached to a machine spindle, by using three displacement sensors fixed to the machine’s table. Its application to error calibration for five-axis machine tools has long been studied. This paper presents software for analyzing the measured R-test trajectories for error diagnosis and numerical compensation for rotary axis location errors and error motions. The developed software first graphically presents the measured R-test trajectories to help a user intuitively understand error motions of the rotary axes. It also numerically parameterizes the rotary axis geometric error parameters, and then generates a compensation table that can be implemented in some latest-generation commercial CNC systems. An actual demonstration of its application to a five-axis machine tool with a universal head (two rotary axes on the spindle side) is presented.

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