6-DOF Single-Inertial Mass, Isotropic Accelerometer With Optical Displacement Sensors

2006 ◽  
Author(s):  
Vladimir Chapsky ◽  
Vladimir Portman ◽  
Ben-Zion Sandler
Keyword(s):  
Light Source ◽  
Optical Sensors ◽  
Optical Measurement ◽  
Data Gathering ◽  
Inertial Mass ◽  
Symmetrical Structure ◽  
Mathematical Algorithm ◽  
Displacement Sensors ◽  
Optical Displacement ◽  
Experimental Apparatus

A novel design of high isotropy single mass six-degree-of-freedom (6-DOF) accelerometer has been developed and investigated. In the accelerometer, six spatial coordinates (three linear and three angular) of the inertial mass and their derivatives are observed by simple measurement of linear displacements of six optimally chosen points of the inertial mass. Calculation of the six acceleration components is then possible according to a specially developed mathematical algorithm. To provide the isotropy of the device’s sensitivity and to achieve the accuracy in the measurement of the linear and angular accelerations, three subsystems of the device — inertial, suspension, and measurement subsystems — have a spatially symmetrical structure. To provide the symmetrical structure of the inertial subsystem, the proof mass is manufactured from uniform material and has a cubic shape. All structural cavities in this cube (light guides and a light source cavity) are symmetrical relative to three coordinate axes. To provide the symmetry of suspension subsystem 24 elastic supports (springs) are mounted by three in all vertexes of the cube in the directions of X-, Y- and Z-axes. The springs have the same dimensions and stiffness. The damping elements (the rubber insets) are inserted into the springs. They are made of the same material and have the identical dimension. The measurement subsystem consists of six differential optical displacement sensors and the light source which is mounted in the center of the cube. Each optical sensor is based on three-component position-sensitive detectors (PSD) of a segmented type. This design ensures output signals that are independent of fluctuations in light source brightness and of optical and electromagnetic interferences. Optical sensors are mounted on the frame of the accelerometer and situated symmetrically opposite to the centers of the square faces of the cube. Six orts of measurement directions form three orthogonal pairs. The experimental model of isotropic 6-DOF accelerometer with differential optical measurement subsystem is manufactured, adjusted and tested. For this purpose the experimental apparatus consisting of the stand with standard accelerometers and computer-controlled data gathering and analysis system (multi-channel amplifier, analog-digital converter and LabView software system) is developed. The preliminary experiment results show that proposed device has high level of signal isotropy and it is hoped to have a good perspective for industrial application were it can replace the complex gyroscopic and combined multi-axis devices.

scholarly journals Upconversion Spectral Rulers for Transcutaneous Displacement Measurements

Sensors ◽  
2021 ◽  
Vol 21 (10) ◽  
pp. 3554
Author(s):  
Melissa M. Suckey ◽  
Donald W. Benza ◽  
John D. DesJardins ◽  
Jeffrey N. Anker
Keyword(s):  
Optical Measurement ◽  
Optical Measurements ◽  
Small Displacement ◽  
Simple Method ◽  
Low Background ◽  
X Ray ◽  
Optical Displacement ◽  
Spectral Peaks ◽  
Displacement Measurements ◽  
Minimal Intensity

We describe a method to measure micron to millimeter displacement through tissue using an upconversion spectral ruler. Measuring stiffness (displacement under load) in muscles, bones, ligaments, and tendons is important for studying and monitoring healing of injuries. Optical displacement measurements are useful because they are sensitive and noninvasive. Optical measurements through tissue must use spectral rather than imaging approaches because optical scattering in the tissue blurs the image with a point spread function typically around the depth of the tissue. Additionally, the optical measurement should have low background and minimal intensity dependence. Previously, we demonstrated a spectral encoder using either X-ray luminescence or fluorescence, but the X-ray luminescence required an expensive X-ray source and used ionizing radiation, while the fluorescence sensor suffered from interference from autofluorescence. Here, we used upconversion, which can be provided with a simple fiber-coupled spectrometer with essentially autofluorescence-free signals. The upconversion phosphors provide a low background signal, and the use of closely spaced spectral peaks minimizes spectral distortion from the tissue. The small displacement noise level (precision) through tissue was 2 µm when using a microscope-coupled spectrometer to collect light. We also showed proof of principle for measuring strain on a tendon mimic. The approach provides a simple method to study biomechanics using implantable sensors.

Stabilized transverse Zeeman laser as a new light source for optical measurement

1980 ◽  
Vol 19 (3) ◽  
pp. 435 ◽  
Author(s):  
H. Takasaki ◽  
N. Umeda ◽  
M. Tsukiji
Keyword(s):  
Light Source ◽  
Optical Measurement ◽  
Zeeman Laser

scholarly journals Depth Data Denoising in Optical Laser Based Sensors for Metal Sheet Flatness Measurement: A Deep Learning Approach

Sensors ◽  
2021 ◽  
Vol 21 (21) ◽  
pp. 7024
Author(s):  
Marcos Alonso ◽  
Daniel Maestro ◽  
Alberto Izaguirre ◽  
Imanol Andonegui ◽  
Manuel Graña
Keyword(s):  
Deep Learning ◽  
Optical Sensors ◽  
Optical Measurement ◽  
Image Data ◽  
Real Data ◽  
Noise Removal ◽  
Metal Sheet ◽  
Superior Performance ◽  
Range Image ◽  
Range Images

Surface flatness assessment is necessary for quality control of metal sheets manufactured from steel coils by roll leveling and cutting. Mechanical-contact-based flatness sensors are being replaced by modern laser-based optical sensors that deliver accurate and dense reconstruction of metal sheet surfaces for flatness index computation. However, the surface range images captured by these optical sensors are corrupted by very specific kinds of noise due to vibrations caused by mechanical processes like degreasing, cleaning, polishing, shearing, and transporting roll systems. Therefore, high-quality flatness optical measurement systems strongly depend on the quality of image denoising methods applied to extract the true surface height image. This paper presents a deep learning architecture for removing these specific kinds of noise from the range images obtained by a laser based range sensor installed in a rolling and shearing line, in order to allow accurate flatness measurements from the clean range images. The proposed convolutional blind residual denoising network (CBRDNet) is composed of a noise estimation module and a noise removal module implemented by specific adaptation of semantic convolutional neural networks. The CBRDNet is validated on both synthetic and real noisy range image data that exhibit the most critical kinds of noise that arise throughout the metal sheet production process. Real data were obtained from a single laser line triangulation flatness sensor installed in a roll leveling and cut to length line. Computational experiments over both synthetic and real datasets clearly demonstrate that CBRDNet achieves superior performance in comparison to traditional 1D and 2D filtering methods, and state-of-the-art CNN-based denoising techniques. The experimental validation results show a reduction in error than can be up to 15% relative to solutions based on traditional 1D and 2D filtering methods and between 10% and 3% relative to the other deep learning denoising architectures recently reported in the literature.

Methodology for the design, production, and test of plastic optical displacement sensors

2016 ◽  
Vol 5 (4) ◽  
Author(s):  
Maik Rahlves ◽  
Christian Kelb ◽  
Eduard Reithmeier ◽  
Bernhard Roth
Keyword(s):  
Large Scale ◽  
Mechanical Performance ◽  
Mechanical Test ◽  
Numerical Models ◽  
Testing Machine ◽  
Displacement Sensor ◽  
Optical Simulation ◽  
Displacement Sensors ◽  
Optical Displacement ◽  
Design Production

AbstractOptical displacement sensors made entirely from plastic materials offer various advantages such as biocompatibility and high flexibility compared to their commonly used electrical and glass-based counterparts. In addition, various low-cost and large-scale fabrication techniques can potentially be utilized for their fabrication. In this work we present a toolkit for the design, production, and test of such sensors. Using the introduced methods, we demonstrate the development of a simple all-optical displacement sensor based on multimode plastic waveguides. The system consists of polymethylmethacrylate and cyclic olefin polymer which serve as cladding and core materials, respectively. We discuss several numerical models which are useful for the design and simulation of the displacement sensors as well as two manufacturing methods capable of mass-producing such devices. Prior to fabrication, the sensor layout and performance are evaluated by means of a self-implemented ray-optical simulation which can be extended to various other types of sensor concepts. Furthermore, we discuss optical and mechanical test procedures as well as a high-precision tensile testing machine especially suited for the characterization of the opto-mechanical performance of such plastic optical displacement sensors.

Design of an Optical Mechanical System for High-Resolution Encoders

2013 ◽  
Vol 284-287 ◽  
pp. 2711-2716
Author(s):  
Yi Hua Fan ◽  
Ching En Chen ◽  
Liao Yong Lou ◽  
Chun Yu Chen
Keyword(s):  
High Resolution ◽  
Light Source ◽  
Experimental System ◽  
Movable Part ◽  
Concave Lens ◽  
Optical Displacement ◽  
Optical Grating ◽  
Fixed Part ◽  
Simulation Results ◽  
The Relationship

An optical mechanism composed of a movable part and a fixed part for the increment high-resolution optical displacement encoders is proposed in this paper. The parallel light emitted from the movable part passes through a double-concave lens and a specially designed optical grating; it is then projected onto a phototransistor array receiver to indicate the displacement of the movable part. The relationship equation of the lens is developed to design an optical mechanism which can enlarge the displacement so that it becomes observable. Based upon the simulation results, a specially designed optical grating is designed to compensate for the deviations on the detecting surface and to derive the increment movement of the light source. The simulation results indicated that the optical mechanism with 50 times magnification could make the 10 nm movement intervals of a light source be about 500 nm movement intervals in the detecting surface. Furthermore, an experimental system with a 200 nm resolution is established to verify the possibility of the proposed structure.

Skew Ray Tracing and Sensitivity Analysis of Geometrical Optics

1999 ◽  
Vol 122 (2) ◽  
pp. 338-349 ◽  
Author(s):  
Psang Dain Lin ◽  
Te-tan Liao
Keyword(s):  
Sensitivity Analysis ◽  
Ray Tracing ◽  
Light Source ◽  
Optical Measurement ◽  
Optical Systems ◽  
System Sensitivity ◽  
Measuring Surface ◽  
Theoretical Predictions ◽  
Medium Boundary ◽  
Boundary Surfaces

In order to improve upon the inconvenient and complicated contemporary analytic techniques employed for optical systems, this paper investigates two important optical topics: (1) the determination of light ray paths and (2) sensitivity analysis of light path parameters with respect to the light source location for occasions when light rays cross medium boundary surfaces. To this end, the traditional laws of reflection and refraction are reformulated in terms of revolution geometry. This results in a set of laws much simpler than the original, suitable for use in mathematical modeling to determine light paths and system sensitivity from location of the light source, optical component location, the equation of the optical component’s surface curve, and the refractive index. Ray tracing and sensitivity analysis of the two most popular boundary surfaces, flat and spherical, are presented as examples. In order to illustrate experimentally the integration of these boundary surfaces into optical systems, an optical measurement system for measuring surface height and orientation, containing a beam splitter and a bi-convex lens, was built. Agreement between the experimental optical system’s performance and the theoretical predictions yielded by the proposed method are excellent. [S1087-1357(00)01501-X]

A Novel High-Resolution Optical Displacement Encoder Design Based on Double-Concave Lens

2010 ◽  
Vol 447-448 ◽  
pp. 579-583
Author(s):  
Yi Hua Fan ◽  
Ying Tsun Lee ◽  
Chun Yu Chen ◽  
Yi Lin Liao ◽  
Ching En Chen
Keyword(s):  
High Resolution ◽  
Light Source ◽  
Measurement Accuracy ◽  
Position Change ◽  
Exit Surface ◽  
Concave Lens ◽  
Optical Detector ◽  
Optical Displacement ◽  
Simulation Results ◽  
Thick Lens

A novel optical displacement encoder was proposed in this paper. An optical mechanism was designed by the equations of thick lens to change and modify the paths of light, and then to get a more visible position change in the optical detector to improve the measurement accuracy. The simulation results indicated that the optical mechanism with 5 mm stroke, which the lens radii of curvature of the incident and the exit surface on the lens were -0.625 cm and 1.25 cm, respectively, and the magnification was 50 times in imaging distance of 38 cm, could make the 1 nm movement intervals of light source to be about 50 nm movement intervals in the detecting surface. Thus we can combine the optical mechanism and a photo-detector array with 50 nm resolution and 25 cm total detecting length to form the optical displacement encoder with 1 nm measuring accuracy.

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