scholarly journals An Improved Step-Type Liquid Level Sensing System for Bridge Structural Dynamic Deflection Monitoring

Sensors ◽  
2019 ◽  
Vol 19 (9) ◽  
pp. 2155 ◽  
Author(s):  
Xijun Ye ◽  
Zhuo Sun ◽  
Xu Cai ◽  
Liu Mei
Keyword(s):  
Measurement Error ◽  
Turbulent Flow ◽  
Measurement Accuracy ◽  
Fluid Velocity ◽  
Step Height ◽  
Liquid Level ◽  
Measurement Point ◽  
Structural Dynamic ◽  
Sensing System ◽  
Step Type

Real-time and accurate monitoring of dynamic deflection is of great significance for health monitoring and condition assessment of bridge structures. This paper proposes an improved step-type liquid level sensing system (LLSS) for dynamic deflection monitoring. Layout of straight-line-type pipeline is replaced by step-type pipeline in this improved deflection monitoring system, which can remove the interference of the inclination angle on the measurement accuracy and is applicable for dynamic deflection monitoring. Fluid dynamics are first analyzed to demonstrate that measurement accuracy is interfered with by the fluid velocity induced by structural vibration, and ANSYS-FLOTRAN is applied for analyzing the influence range caused by the turbulent flow. Finally, a step-type LLSS model is designed and experimented with to verify the influence of the three key parameters (initial displacement excitation, step height, and distance from the measurement point to the elbow) on the measurement accuracy, and the reasonable placement scheme for the measurement point is determined. The results show that the measurement accuracy mainly depends on the turbulent flow caused by step height. The measurement error gets smaller after about 1.0 m distance from the elbow. To ensure that the measurement error is less than 6%, the distance between the measurement point and the elbow should be larger than 1.0 m.

Design of a Sensor System Using Fiber Bragg Grating for Liquid Level and Liquid Density Measurement

2020 ◽  
Vol 18 (12) ◽  
pp. 889-893
Author(s):  
Kalyan Biswas
Keyword(s):  
Fiber Bragg Grating ◽  
Density Measurement ◽  
Sensor System ◽  
Liquid Level ◽  
Bragg Grating ◽  
Liquid Density ◽  
Bragg Wavelength ◽  
Sensing System ◽  
System A ◽  
Level Monitoring

In this work, a simple but versatile sensing system for very accurate sensing of liquid level and liquid density is presented. The sensor works based on basic strain sensitivity of Fiber Bragg Grating (FBG) and principle of liquid obeying Archimedes’ law of buoyancy. In this system, a cylindrical shaped mass suspended from a Fiber Bragg Grating and partially immersed in the liquid to be sensed. If the liquid level in the container or liquid density varies, that change the up thrust on the suspended mass and load on the Fiber will be changed accordingly. The change in the load on Fiber changes strain on the FBG and the reflected Bragg wavelength also changes. The proposed device with proper calibration should be able to carry out real time and nonstop liquid level and liquid density measurements. A mathematical analysis of the system considering liquid properties and geometrical structure of the suspended mass is presented here. Sensitivity of the system for liquid level monitoring is also reported. Achieved results shows the path for the utilization of the proposed sensor system for precise liquid density measurement and liquid level sensing in very large storage tanks used for commercial/residential applications.

scholarly journals A Portable Support Attitude Sensing System for Accurate Attitude Estimation of Hydraulic Support Based on Unscented Kalman Filter

Sensors ◽  
2020 ◽  
Vol 20 (19) ◽  
pp. 5459 ◽  
Author(s):  
Xuliang Lu ◽  
Zhongbin Wang ◽  
Chao Tan ◽  
Haifeng Yan ◽  
Lei Si ◽  
...  
Keyword(s):  
Kalman Filter ◽  
Measurement Error ◽  
Unscented Kalman Filter ◽  
Attitude Estimation ◽  
Measurement Unit ◽  
Hydraulic Support ◽  
Sensing System ◽  
Rock Structure ◽  
Gradient Descent Algorithm ◽  
Yaw Angle

To measure the support attitude of hydraulic support, a support attitude sensing system composed of an inertial measurement unit with microelectromechanical system (MEMS) was designed in this study. Yaw angle estimation with magnetometers is disturbed by the perturbed magnetic field generated by coal rock structure and high-power equipment of shearer in automatic coal mining working face. Roll and pitch angles are estimated using the MEMS gyroscope and accelerometer, and the accuracy is not reliable with time. In order to eliminate the measurement error of the sensors and obtain the high-accuracy attitude estimation of the system, an unscented Kalman filter based on quaternion according to the characteristics of complementation of the magnetometer, accelerometer and gyroscope is applied to optimize the solution of sensor data. Then the gradient descent algorithm is used to optimize the key parameter of unscented Kalman filter, namely process noise covariance, to improve the accuracy of attitude calculation. Finally, an experiment and industrial application show that the average measurement error of yaw angle is less than 2° and that of pitch angle and roll angle is less than 1°, which proves the efficiency and feasibility of the proposed system and method.

The Measurement of Liquid Level Based on Peak Image Recognition Technique

2012 ◽  
Vol 566 ◽  
pp. 505-510
Author(s):  
Hui Dan Cao ◽  
Yu Ming Shen
Keyword(s):  
Measurement Error ◽  
Liquid Level ◽  
Level Gauge ◽  
Measurement Technology ◽  
Gamma Correction ◽  
Image Measurement ◽  
Transparent Glass ◽  
Calibration Facility ◽  
Recognition Technique ◽  
Illuminating System

A new kind of device measuring liquid level automatically is developed which is composed of camera, illuminating system and industrial computer. It’s based on image measurement technology. The image of the transparent glass liquid level gauge which is installed on the volumetric tank of a flow calibration facility is captured by a camera. After a series of image pre-processing, such as interception, gamma correction, edge detection and so on, the value of liquid level which is the liquid level of the tank can be got by so called peak method. The measurement error is 0.1mm.

Badge-Type Noise Dosimeters Used in the Mining Industry

2009 ◽  
Author(s):  
John P. Homer
Keyword(s):  
Measurement Error ◽  
Measurement Accuracy ◽  
Mining Industry ◽  
Mine Safety ◽  
Type Versus ◽  
Health Administration ◽  
Laboratory Measurements ◽  
Type Design ◽  
Safety And Health ◽  
Influence Measurement

Currently, a number of manufacturers have developed and made commercially available badge-type (cordless) noise dosimeters. Previous studies conducted by the Mine Safety and Health Administration (MSHA) revealed that microphone size and placement/orientation significantly influence measurement error. The badge-type design houses the microphone within a significantly larger casing than does the traditional corded-type dosimeter. This presents concern that badge-type designs may significantly inhibit measurement accuracy. The purpose of this study is to evaluate the casing of various badge-type dosimeters in order to discern conditions and assess the extent to which the badge-type design contributes toward measurement error in comparison with the traditionally used corded dosimeter. For this, a series of laboratory measurements were conducted employing various commercially available badge-type casings and corded counterparts. Corresponding results are summarized and extended to conclusions regarding the effect of microphone casing design, badge-type versus corded, on measurement accuracy for personal noise dosimetry.

Experiments on Backward-Facing Step Flows Preceding a Filter

2007 ◽  
Author(s):  
S. Yao ◽  
C. Krishnamoorthy ◽  
F. W. Chambers
Keyword(s):  
Reynolds Number ◽  
Turbulent Flow ◽  
Separated Flow ◽  
Reynolds Numbers ◽  
Velocity Profiles ◽  
Step Height ◽  
Reattachment Point ◽  
Backward Facing Step ◽  
Air Filters ◽  
Air Filter

The resistance of automotive air filters alters upstream pressure gradients and thereby affects flow separation, the velocity distributions over the filter, and the performance of the filter. Air filters provide a resistance sufficient to alter flows, but not enough to make face velocities uniform. The backward-facing step flow is an archetype with a separation that resembles those found in automotive air filter housings. To gain insight to the problem of separation and filters, experiments were conducted measuring velocity fields for air flows in a 10:1 aspect ratio rectangular duct with a backward-facing step with and without the resistance of an air filter mounted downstream. The expansion ratio for the step was 1:2. The filter was mounted 4.25 and 6.75 step heights downstream of the step; locations both upstream and downstream of the nominal 6 step-height no-filter reattachment point. Experiments were performed at four Reynolds numbers between 2000 and 10,000. The Reynolds numbers were based on step height and inlet maximum velocity. The inlet velocity profiles at the step were developed. A Laser Doppler Anemometer (LDA) was used to measure velocity profiles and map separated regions between the step and the filter. The results indicate that the filter tends to decrease the streamwise velocity on the non-separated side of the channel and increase it on the separated, step, side compared to the no-filter flow. Non-separated flow tends to separate due to the deceleration and separated flow reattaches before the filter, whether the filter is placed at 4.25 or 6.75 step heights. The literature shows that without a filter the reattachment location depends on the Reynolds number in the laminar and transitional regimes, but is constant for turbulent flow. However, the area of the reversed flow may vary with Reynolds number for turbulent flow. With the filter at 4.25 step heights, the area of reversing flow is reduced significantly, and the Reynolds number has little effect on the main properties of the flow. With the filter at 6.75 step heights, the reversing flow area decreases as the Reynolds number increases though the reattachment point is fixed just upstream of the filter.

Analysis of Underground Space Azimuth Measuring and Data Processing in a Tunnel

2014 ◽  
Vol 580-583 ◽  
pp. 2828-2832
Author(s):  
Tao Wang ◽  
Hu Rong Duan ◽  
Liu Tao Jiang ◽  
Shun Liu
Keyword(s):  
Measurement Error ◽  
Data Processing ◽  
Measurement Accuracy ◽  
High Accuracy ◽  
Measurement Precision ◽  
Underground Space ◽  
Processing Theory ◽  
Constant Measurement ◽  
Survey Results ◽  
Final Orientation

In this paper, we studied high accuracy azimuth measuring on improving the precision of traverse azimuth from the perspective of transfixion measurement error in a tunnel project. On the basis of a feasible scheme using Gyro Total Station measurement is given. Data processing theory and method are also introduced with a successful tunnel transfixion case. The transfixion results show that the instrument constant measurement precision is 3.7", baseline coordinates azimuth measurement accuracy is 4.8" into tunnel, the final orientation coordinate azimuth value and traverse measurement values differ is 11", to guide the construction of the gyro orientation with survey results achieved tunnel through smoothly.

Vision-Based Measurement of Part Deformation and Misalignment for Deformable Cylindrical Peg-in-Hole Tasks

2005 ◽  
Vol 219 (6) ◽  
pp. 589-606 ◽  
Author(s):  
J. Y. Kim
Keyword(s):  
Success Rate ◽  
Measurement Accuracy ◽  
Arbitrary Point ◽  
Image Plane ◽  
Experimental Results ◽  
Sensing System ◽  
Visual Sensing ◽  
Standard Resolution ◽  
Series Of Experiments ◽  
Assembly Operations

For successful assembly of deformable parts, information about their deformation and possible misalignments between the holes and their respective mating parts is essential. Such information can be mainly acquired from visual sensors. In this paper, part deformation and misalignment in cylindrical peg-in-hole tasks are measured by using a visual sensing system. First, the configuration and the specifications of the system, such as resolution, are described. Next, a series of experiments to measure the position of an arbitrary point are performed and its measurement accuracy is investigated. Then, an algorithm to estimate the centre-line and deformation of a cylindrical peg and an algorithm to divide and recognize a peg and a hole separately in an image are presented. On the basis of these algorithms, a series of experiments to measure part shape as part deformation are performed. Finally, an algorithm to select two views from the four on the image plane and an algorithm to estimate the centre of an occluded hole are presented. On the basis of these algorithms, a series of experiments to measure misalignment are performed. Experimental results show that the errors in measuring part deformation are approximately less than five or seven times the standard resolution of the system, and the errors in measuring misalignment are less than three or four times the standard resolution. Thereby, the system and the proposed algorithms are effective in measuring part deformation and misalignment and will dramatically increase the success rate in deformable assembly operations.

scholarly journals Development of the initial concepts of metrological support of measuring and calculated operations in automating measurements

2019 ◽  
pp. 87-89
Author(s):  
Sergey Mikhaylovich Morozov ◽  
Konstantin Anatolyevich Kuzmin ◽  
Lyudmila Ivanovna Kochetkova ◽  
Elena Vitalyevna Balmashnova
Keyword(s):  
Control System ◽  
Measurement Error ◽  
Statistical Methods ◽  
Metrological Support ◽  
Measurement Accuracy ◽  
Automated Control ◽  
Reliability Indicators ◽  
Automated Control System

The article discusses the metrological support of the automated control system and the task of increasing the reliability of the measured parameters by increasing the measurement accuracy in the need to determine the conditions under which the correctness of the applicability of probabilistic-statistical methods to the estimates of measurement error is observed and the reliability of the control reliability indicators is met.

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