Numerical Simulation Method for Velocity Sensors Calibration in High Speed Flows

The paper presents RANS numerical simulations carried out to calibrate the Pitot tube velocity measurements in order to extend the accurate measurement range to high velocities, up to 250 m/s. Three calibration methods are proposed, able to reduce the rms error of the velocity measurement from an initial value of 6.5 m/s, to 3.11 m/s, 2.33 m/s, and 0.08 m/s, respectively. As the accuracy of the calibration method increases, the complexity and the portability of the method for other flows and other Pitot tube dimensions is found to decrease.

Download Full-text

A Novel, High-Frequency, Reciprocal Calibration Method for Dynamic Pressure Sensors Used in High-Speed Flows

AIAA Scitech 2020 Forum ◽

10.2514/6.2020-2213 ◽

2020 ◽

Author(s):

David A. Mills ◽

Tai-An Chen ◽

Stephen Horowitz ◽

William Patterson ◽

Mark Sheplak

Keyword(s):

High Frequency ◽

High Speed ◽

Dynamic Pressure ◽

Pressure Sensors ◽

Calibration Method ◽

High Speed Flows

Download Full-text

Density and velocity measurements in high speed flows

10.2514/6.1968-392 ◽

1968 ◽

Cited By ~ 1

Author(s):

W. MCCROSKEY

Keyword(s):

High Speed ◽

Velocity Measurements ◽

High Speed Flows

Download Full-text

The Calibration Method of a stereo-Vision-Based Coordinates Measurement System via a Two-Axis Turntable--The Combination of Stereo Vision and Turntable

Recent Patents on Mechanical Engineering ◽

10.2174/2212797614666210223170442 ◽

2021 ◽

Vol 14 ◽

Author(s):

Zimiao Zhang ◽

Zhiwu Wang ◽

Shihai Zhang ◽

Anqi Fu

Keyword(s):

Stereo Vision ◽

Measurement System ◽

Vision System ◽

Three Dimensional ◽

Calibration Method ◽

Measurement Range ◽

Measurement Technology ◽

Rotation Axes ◽

Internal Parameters ◽

Calibration Methods

Background: Stereo-vision-based three-dimensional coordinates measurement technology has been widely applied in the military or civil fields. There are two problems that need to be solved. The first problem is that each camera internal parameters and the two cameras external parameters need to be calibrated. To increase the measurement range, usually the turntable is used with the stereo vision system together. The second problem is the calibration of the turntable. Objective: The aim of the study is to construct and calibrate a stereo-vision-based coordinates measurement system via a two-axis turntable. Methods: Considering that the internal parameters of each camera do not change during the measurement process and the complicated optimization process of one-step self-calibration, a two-step stereo vision calibration method is proposed. In the first step, we calibrate the internal parameters of each camera through a specially designed planar target with circular points. In the second step, on the basis of the calibrated results of the internal parameters, the two cameras external parameters are calibrated through a simple target which could be distributed in the measurement volume. For the calibration of the two-axis turntable, we calibrated the rotation axes of the turntable and the coordinates of points in the 3D space could be measured considering the non-orthogonality of the axes. Results: Some experiments are provided to examine the calibration methods we proposed. They are the plane target measurement experiments, the standard ball center coordinates measurement experiments and target pose measurement experiments. Experiment results demonstrate the superiority of the calibration method we proposed. Conclusion: We studied the calibration methods of the stereo-vision-based coordinates measurement system via a two-axis turntable. The experimental results show the measurement accuracy of our system is less than 0.1mm.

Download Full-text

Density and velocity measurements in high-speed flows.

AIAA Journal ◽

10.2514/3.4879 ◽

1968 ◽

Vol 6 (9) ◽

pp. 1805-1808 ◽

Cited By ~ 3

Author(s):

W. J. McCROSKEY

Keyword(s):

High Speed ◽

Velocity Measurements ◽

High Speed Flows

Download Full-text

Quasi Single Point Calibration Method for High-Speed Measurements of Resistive Sensors

Micromachines ◽

10.3390/mi10100664 ◽

2019 ◽

Vol 10 (10) ◽

pp. 664 ◽

Cited By ~ 3

Author(s):

Botín-Córdoba ◽

Oballe-Peinado ◽

Sánchez-Durán ◽

Hidalgo-López

Keyword(s):

High Speed ◽

Single Point ◽

Calibration Method ◽

Digital Conversion ◽

Interface Circuits ◽

Sensor Reading ◽

Mean Estimation ◽

Calibration Methods ◽

Proposal A ◽

The Mean

Direct interface circuits are a simple, inexpensive alternative for the digital conversion of a sensor reading, and in some of these circuits only passive calibration elements are required in order to carry out this conversion. In the case of resistive sensors, the most accurate methods of calibration, namely two-point calibration method (TPCM) and fast calibration methods I and II (FCMs I and II), require two calibration resistors to estimate the value of a sensor. However, although FCMs I and II considerably reduce the time necessary to estimate the value of the sensor, this may still be excessive in certain applications, such as when making repetitive readings of a sensor or readings of a large series of sensors. For these situations, this paper proposes a series of calibration methods that decrease the mean estimation time. Some of the proposed methods are based on the TPCM and quasi single-point calibration methods, while others make the most of the advantages of FCM II and fast quasi single-point calibration methods. In general, the proposed methods significantly reduce estimation times in exchange for a small increase in errors. To validate the proposal, a circuit with a Xilinx XC3S50AN-4TQG144C FPGA has been designed and resistors in the range (267.56 Ω, 7464.5 Ω) have been measured. For 20 repetitive measurements, the proposed methods achieve time reductions of up to 61% with a relative error increase of only 0.1%.

Download Full-text