Development of a Gas Flow Sensor Based on FS5 Hot-Film Probe

2014 ◽  
Vol 568-570 ◽  
pp. 537-541
Author(s):  
Lei Yang ◽  
Jia Qiang Yang
Keyword(s):  
High Precision ◽  
Output Voltage ◽  
Gas Flow ◽  
Characteristic Curve ◽  
Measurement Data ◽  
Least Square Method ◽  
Industrial Applications ◽  
Least Square ◽  
Flow Sensor ◽  
Hot Film

On the basis of thermal measuring method, a hot-film gas flow sensor is proposed. Its sensitive element is a FS5 probe, which is integrated with measuring resistance and temperature compensating resistance inside. In order to achieve temperature compensation, the main measuring circuit is designed. Considering minimizing errors in this circuit, the temperature correcting circuit is added to further modify output voltage. By fitting measurement data of gas flow and the final output voltage with least square method, an operating characteristic curve is obtained as well as its 4th order polynomial. Under equivalent conditions, the proposed sensor, a high-precision standard sensor and an industrial sensor are experimented upon and the contrast analysis of their measurement results is given. The experimental results prove that the proposed sensor has high precision with measurement error less than 3%. Therefore the proposed sensor is feasible for industrial applications.

scholarly journals A New Algorithm for Reconstructing Two-Dimensional Temperature Distribution by Ultrasonic Thermometry

2015 ◽  
Vol 2015 ◽  
pp. 1-10 ◽  
Author(s):  
Xuehua Shen ◽  
Qingyu Xiong ◽  
Weiren Shi ◽  
Shan Liang ◽  
Xin Shi ◽  
...  
Keyword(s):  
Temperature Distribution ◽  
Ultrasound Velocity ◽  
Least Square Method ◽  
Reconstruction Algorithm ◽  
Industrial Applications ◽  
Least Square ◽  
Distribution Models ◽  
Practical Applications ◽  
Reconstruction Performance ◽  
Reconstructed Temperature

Temperature, especially temperature distribution, is one of the most fundamental and vital parameters for theoretical study and control of various industrial applications. In this paper, ultrasonic thermometry to reconstruct temperature distribution is investigated, referring to the dependence of ultrasound velocity on temperature. In practical applications of this ultrasonic technique, reconstruction algorithm based on least square method is commonly used. However, it has a limitation that the amount of divided blocks of measure area cannot exceed the amount of effective travel paths, which eventually leads to its inability to offer sufficient temperature information. To make up for this defect, an improved reconstruction algorithm based on least square method and multiquadric interpolation is presented. And then, its reconstruction performance is validated via numerical studies using four temperature distribution models with different complexity and is compared with that of algorithm based on least square method. Comparison and analysis indicate that the algorithm presented in this paper has more excellent reconstruction performance, as the reconstructed temperature distributions will not lose information near the edge of area while with small errors, and its mean reconstruction time is short enough that can meet the real-time demand.

Automatic Reverse Engineering Based on Reconstructing Measurement Data in 3D-Lattice

2012 ◽  
Vol 523-524 ◽  
pp. 414-419
Author(s):  
Kiyomoto Tsushima ◽  
Hideki Aoyama
Keyword(s):  
Reverse Engineering ◽  
Mathematical Models ◽  
Measurement Data ◽  
Least Square Method ◽  
Lattice Points ◽  
Least Square ◽  
Physical Models ◽  
Engineering System ◽  
Surface Data ◽  
Data Density

Reverse engineering systems are used to construct mathematical models of physical models such as clay model based on measurement data. In this study, we proposed a reverse engineering method which can construct high quality surface data automatically. This method consists of the following steps; The first globally and regionally smooths measured data based on the target shape by fitting quadric surface to measurement data. The second defines quadric surfaces and converts measurement points into 3D lattice points to obtain uniform measurement data density. As the positions of measurement data are converted from coordinate values into 3D lattice points, it is easier to find neighboring points and clarify neighboring relations between surfaces. The third acquires segment measurement data based on maximum curvatures and normals at each point. The last defines NURBS surfaces for each segment using the least square method to average positional errors. In order to validate the effectiveness of the proposed method, we developed a reverse engineering system and constructed mathematical models through basic experiments using clay car model measurement data.

scholarly journals Fabrication and Evaluation of a Flexible MEMS-Based Microthermal Flow Sensor

Sensors ◽  
2021 ◽  
Vol 21 (23) ◽  
pp. 8153
Author(s):  
Myoung-Ock Cho ◽  
Woojin Jang ◽  
Si-Hyung Lim
Keyword(s):  
Flow Velocity ◽  
Output Voltage ◽  
Gas Flow ◽  
Fluid Velocity ◽  
Wheatstone Bridge ◽  
Polyimide Film ◽  
Flow Sensor ◽  
Healthcare Applications ◽  
Labview Software ◽  
Liquid Flows

Based on the results of computational fluid dynamics simulations, this study designed and fabricated a flexible thermal-type micro flow sensor comprising one microheater and two thermistors using a micro-electromechanical system (MEMS) process on a flexible polyimide film. The thermistors were connected to a Wheatstone bridge circuit, and the resistance difference between the thermistors resulting from the generation of a flow was converted into an output voltage signal using LabVIEW software. A mini tube flow test was conducted to demonstrate the sensor’s detection of fluid velocity in gas and liquid flows. A good correlation was found between the experimental results and the simulation data. However, the results for the gas and liquid flows differed in that for gas, the output voltage increased with the fluid’s velocity and decreased against the liquid’s flow velocity. This study’s MEMS-based flexible microthermal flow sensor achieved a resolution of 1.1 cm/s in a liquid flow and 0.64 cm/s in a gas flow, respectively, within a fluid flow velocity range of 0–40 cm/s. The sensor is suitable for many applications; however, with some adaptations to its electrical packaging, it will be particularly suitable for detecting biosignals in healthcare applications, including measuring respiration and body fluids.

An improved kinematic calibration method for serial manipulators based on POE formula

Robotica ◽  
2018 ◽  
Vol 36 (8) ◽  
pp. 1244-1262 ◽  
Author(s):  
Chenguang Chang ◽  
Jinguo Liu ◽  
Zhiyu Ni ◽  
Ruolong Qi
Keyword(s):  
High Precision ◽  
Least Square Method ◽  
Calibration Method ◽  
Error Model ◽  
Least Square ◽  
Identification Accuracy ◽  
Kinematic Calibration ◽  
Serial Manipulators ◽  
Serial Robots ◽  
Generic Modeling

SUMMARYExisting measurement equipments easily determine position with high precision. However, they evaluate orientation with low precision. It is necessary to minimize the effect of measurement error on identification accuracy. In this study, a method for kinematic calibration based on the product of exponentials (POE) is presented to improve the absolute positioning accuracy of a sliding manipulator. An error model with uniform and generic modeling rules is established in which the tool frame is selected as the reference frame. Furthermore, the redundant parameters of the error model are removed. Subsequently, the actual kinematic parameters are identified by using the least square method. Finally, the process of the improved method is discussed. Kinematic calibration simulations of a sliding manipulator are implemented. The results indicate that the proposed method significantly improves the precision of the sliding manipulator. The improved POE kinematic calibration method offers convenience, efficiency, and high precision. The proposed method can be applied to all types of serial robots with n-DOF

Inspection of Large Guide Rail Precision Based on Bistatic Measurement Method

2013 ◽  
Vol 791-793 ◽  
pp. 945-948 ◽  
Author(s):  
Yue Liu ◽  
Zhi Wei Hao ◽  
Tian Tian Ren
Keyword(s):  
Coordinate System ◽  
High Precision ◽  
Measurement Method ◽  
Least Square Method ◽  
Least Square ◽  
Guide Rail ◽  
Total Station ◽  
Measuring Tool

Use two total stations cooperating with each other to measure the straightness of the guide rail. The straightness can test the accuracy of a large rail. Put the coordinates measuring with the two total station instruments to the same user coordinate system, take a key point between some distance with the auxiliary measuring tool of high precision, measure and record the key point s coordinate values. According to them, it can calculate the straightness of guide rail by using the least square method. The straightness accuracy of bistatic measurement can reach below 0.05mm, so it can meet the accuracy requirements.

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