A Fiber Optic Sensor for Surface Roughness Measurement

1998 ◽  
Vol 120 (2) ◽  
pp. 359-367 ◽  
Author(s):  
C. Bradley ◽  
J. Bohlmann ◽  
S. Kurada

A fiber optical interferometer system is described for non-contact measurement of surface topography. The system employs a fiber optic guide and lens arrangement that forms an interferometric cavity between the lens front face and the test surface. Changes in the surface topography are manifested as phase changes between the light reflected from the surface and the front face of the lens. An electronic control and data acquisition system converts the phase change into a voltage signal proportional to surface height. The system is calibrated and compared with stylus surface profile measurements performed on a standard set of machined surface samples. Comparison of the amplitude parameter, Ra, shows differences of between 17 percent and 34 percent across the set of samples, whereas, two spatial parameters, frequency and peak count, consistently compare within 1 percent to 12 percent throughout the Ra range: 0.42 μm ≤ Ra ≤ 2.89 μm.

Metrologiya ◽  
2020 ◽  
pp. 38-51
Author(s):  
V. N. Astapov ◽  
I. N. Kozlova

This article presents the rationale and methodology for developing an intrinsically safe device, namely, a hydrostatic fiber optic sensor with a position-sensitive detector for monitoring the level of oil products in large-capacity tanks at oil depots and during pumping in a raw material warehouses. This device suitable for continuous monitoring of the liquid level, based on the measurement of a hydrostatic column of liquid with automatic offset of changes in the density of the liquid. Offset is carried out by means of a displacer (a fully submerged float), inside which a housing with a position-sensitive detector (PSD) is integrated. Theoretical validation of the bellows suspension usage for a displacer is given. During filling a container with a liquid whose level is measured, liquid bellows, the movement of which is recorded by an optical triangulation sensor using the reflected infrared ray incident on the bottom of the bellows. The principle of the triangulation sensor operation is based on the geometric properties of the triangles. The pulses of infrared radiation come through a fiber optic cable. In order to measure the movement of the surface (the bottom of the bellows) by measuring the movement of the reflected beam, a position-sensitive detector is used, which is located in a remote controller. In this device for the intrinsic safety problem solution, optical inputs of a fiber optic flat cable are located in the active zone of the sensor, which is connected to the optical inputs of a position-sensitive detector, operated on the principles of photoelectric effect. The light spot moving along the sensitive zone and converted by the detector into a one-dimensional signal proportional to the distance to the object. hydrostatically applies pressure over the entire effective area of the measuring


2011 ◽  
Vol 14 (4) ◽  
pp. 66-72 ◽  
Author(s):  
S.M. Al-Hilly ◽  
◽  
Z. E. Khaleel ◽  
A.F. Alrubaye ◽  
◽  
...  

Actuators ◽  
2021 ◽  
Vol 10 (6) ◽  
pp. 107
Author(s):  
Nakash Nazeer ◽  
Xuerui Wang ◽  
Roger M. Groves

This paper presents a study on trailing edge deflection estimation for the SmartX camber morphing wing demonstrator. This demonstrator integrates the technologies of smart sensing, smart actuation and smart controls using a six module distributed morphing concept. The morphing sequence is brought about by two actuators present at both ends of each of the morphing modules. The deflection estimation is carried out by interrogating optical fibers that are bonded on to the wing’s inner surface. A novel application is demonstrated using this method that utilizes the least amount of sensors for load monitoring purposes. The fiber optic sensor data is used to measure the deflections of the modules in the wind tunnel using a multi-modal fiber optic sensing approach and is compared to the deflections estimated by the actuators. Each module is probed by single-mode optical fibers that contain just four grating sensors and consider both bending and torsional deformations. The fiber optic method in this work combines the principles of hybrid interferometry and FBG spectral sensing. The analysis involves an initial calibration procedure outside the wind tunnel followed by experimental testing in the wind tunnel. This method is shown to experimentally achieve an accuracy of 2.8 mm deflection with an error of 9%. The error sources, including actuator dynamics, random errors, and nonlinear mechanical backlash, are identified and discussed.


Author(s):  
Yadira A. Fuentes-Rubio ◽  
Rene F. Dominguez-Cruz ◽  
Oscar Baldovino-Pantaleon ◽  
Carlos Ruiz-Zamarreno ◽  
Francisco J. Arregui

2021 ◽  
Vol 53 (5) ◽  
Author(s):  
D. Jauregui-Vazquez ◽  
M. E. Gutierrez-Rivera ◽  
D. F. Garcia-Mina ◽  
J. M. Sierra-Hernandez ◽  
E. Gallegos-Arellano ◽  
...  

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