scholarly journals A Laser-Based On-Machine Measuring System for Profile Accuracy of Double-Headed Screw Rotor

Sensors ◽  
2019 ◽  
Vol 19 (23) ◽  
pp. 5059 ◽  
Author(s):  
Dong ◽  
Xu ◽  
Sun ◽  
Liu
Keyword(s):  
Measurement Accuracy ◽  
Measuring System ◽  
Threshold Function ◽  
Great Length ◽  
Adaptive Wavelet ◽  
Accuracy Measurement ◽  
Fitting Method ◽  
Screw Rotor ◽  
Profile Accuracy ◽  
Screw Pitch

Great length, large weight and other factors may cause difficulty in measuring the profile accuracy of the double-headed screw rotor. To solve this problem, an on-machine measuring system based on a laser-displacement sensor (LDS) was designed and implemented in this paper by taking an LXK100 four-axis whirlwind milling machine as the carrier. To improve the measurement accuracy of the system, the generalized variable-structural-element morphological method, polynomial interpolation algorithm and ellipse fitting method were first combined to realize the rapid subpixel centroid extraction from a noise-containing spot image, thus improving the data acquisition accuracy of the LDS, and then the hybrid method was experimentally verified. Next, a wavelet threshold function with high-order differentiability and adaptive wavelet coefficient contractility was constructed based on the hyperbolic tangent function, so as to inhibit the disturbance from random errors and preserve real profile information, and this method was simulated and verified. Subsequently, a smoothing algorithm for point cloud data was proposed based on the Lagrange multiplier method to avoid the defect of the piecewise curve-fitting method, that is, function continuity and differentiability could not be satisfied at piecewise points. Finally, the profile accuracy was calculated in real time according to the data reconstruction result and the machining quality was judged. The measurement experiment of the double-headed screw rotor indicates that the proposed on-machine measuring system can complete the profile accuracy measurement for a screw pitch within 39.7 s with measurement accuracy reaching ±8 μm, and the measurement uncertainties of the major axis, minor axis and screw pitch are 0.72 μm, 0.69 μm and 1.24 μm, respectively. Therefore, the measurement accuracy and efficiency are both remarkably improved.

Rotating Accuracy Measurement System of Spindle Based on Three Point Method

2013 ◽  
Vol 333-335 ◽  
pp. 167-171
Author(s):  
Peng Qing Wang ◽  
Hong Jun Wang ◽  
He Peng Gao
Keyword(s):  
Personal Computer ◽  
Rotating Machinery ◽  
Point Method ◽  
Measuring System ◽  
Harmonic Suppression ◽  
Construction Site ◽  
Software Module ◽  
Accuracy Measurement ◽  
Sensor Arrangement ◽  
On Line

In order to measure the rotating machinery fault quickly and conveniently at a construction site, a new measuring system of rotating accuracy of spindle was developed according to three point method. With summarizing the principle of error separation technique based on three point method, the function, hardware construction and software module of this module were introduced. The problem of harmonic suppression is relieved by changing the sensor arrangement. The measuring system mainly consists of three eddy current sensors ,a acquisition card and a personal computer. After a few parameters were inputted, the rotation accuracy of calculation and display could be carried out automatically on line at a construction site.

scholarly journals Analysis of metrological characteristics of elbow flowmeter under rotating state

2021 ◽  
Vol 12 ◽  
pp. 24
Author(s):  
Yu Wang ◽  
Ruiwei Li ◽  
Lin Luo ◽  
Lin Ruan
Keyword(s):  
Flow Rate ◽  
Measurement Accuracy ◽  
Discharge Coefficient ◽  
Water Flow Rate ◽  
Internal Flow ◽  
Metrological Characteristics ◽  
Centrifugal Acceleration ◽  
Flow Rate Measurement ◽  
Fitting Method ◽  
Cfd Method

The application of elbow flowmeter in rotary equipments is beneficial to reduce the pipeline complexity. However, the intervention of centrifugal acceleration will lead to the change of metrological characteristics of elbow flowmeter. Based on the analysis of the differential pressure formation mechanism of the environmental acceleration on the elbow flowmeter, the calculation formula of the flow rate measurement with the elbow flowmeter in the rotating state is derived, and the fitting method of the discharge coefficient is put forward. The CFD method was used to analyze the internal flow field of the elbow flowmeter under rotating state, summarize the pressure distribution characteristics of the pipe wall, and verify the feasibility of the discharge coefficient fitting strategy by simulation. The results show that for the elbow flowmeters with diameters of 10 mm and 15 mm and the radius to diameter ratio of 1.5, as long as the water flow rate is between 1.5 m/s and 5 m/s, the measurement accuracy can be guaranteed to be above 4%.

Dynamic Inverse Model for Multi-Sensor Measurement System Based on Wavelet Neural Network

2012 ◽  
Vol 499 ◽  
pp. 335-339
Author(s):  
Dong Zhi Zhang ◽  
Bo Kai Xia ◽  
Kai Wang ◽  
Jun Tong ◽  
Nian Zhen Yang
Keyword(s):  
Neural Network ◽  
Measuring Method ◽  
Wavelet Neural Network ◽  
Inverse Model ◽  
Measuring System ◽  
Water Mixture ◽  
Accuracy Measurement ◽  
Sensing Technology ◽  
Dynamic Inverse ◽  
Digital Oilfield

As traditional measuring method based on dielectric coefficients shows cross-sensitivity for multi-factor in the measurement of oil/water mixture, it can not meet the requirements of digital oilfield construction. Therefore, this paper presents an inverse model of wavelet neural network (WNN) combining with multi-sensing technology for achieving high-accuracy measurement of water content in crude oil. The simulation and experimental results demonstrate that the proposed method is available to eliminate the cross-coupling effects of multi-factors. The method has higher measurement accuracy and stronger generalization than the model built by BP-NN, and opens a versatile approach in nonlinear error calibration for multi-factors measuring system.

Study on Measuring System of Automatic Image Alignment Refractive Index Based on New Mathematical Model

2014 ◽  
Vol 609-610 ◽  
pp. 1319-1323
Author(s):  
Qing Hua Yao ◽  
Miao Cao ◽  
Chang Liu
Keyword(s):  
Refractive Index ◽  
Optical Transmission ◽  
Optical Glass ◽  
Measuring System ◽  
Practical Significance ◽  
High Demand ◽  
Accuracy Measurement ◽  
General Instrument ◽  
Measurement Repeatability ◽  
High Accuracy Measurement

With the development of measuring technology,the measuring accuracy of optical glass refractive index of the increasingly high demand,V prism refractometers is major general instrument for measuring the refractive index of optical glass,not only the simple device,convenient measurement,and this method has high precision performance,however,the accuracy is only attained ,which in the regulation of national metrology verification and the introduction of V prism refractometers in the literature,the classic formula calculation principle formula error caused by refractive index has more than .Based on the mechanical structure and optical transmission to improve the original V prism refractometers the refractive index of air,by considering the influence on measurement precision of V prism refractometer,to mathematical modeling of V prism refractometer the principle formula,V can be measured refractive prism refractometer rate accuracy increased to ,measurement repeatability less than ,has important practical significance for realizing high accuracy measurement of the refractive index of optical glass.

Multi-Frequency Heterodyne Phase Shift Technology in 3-D Measurement

2013 ◽  
Vol 774-776 ◽  
pp. 1582-1585 ◽  
Author(s):  
Le Wang ◽  
Lei Song ◽  
Li Jun Zhong ◽  
Peng Xin ◽  
Shuai Li ◽  
...  
Keyword(s):  
Phase Shift ◽  
Small Area ◽  
Fringe Pattern ◽  
Measurement Accuracy ◽  
High Efficiency ◽  
Median Filter ◽  
Distinct Advantage ◽  
Accuracy Measurement ◽  
Fringe Patterns ◽  
Spin Filtering

According to the characteristics of the fringe patterns noise, came up with a small area spin filtering noise cancellation algorithm based on parallel marker technology. It means that preprocess the fringe pattern before spin filtering, then did a median filter and calculated the stripe direction, finally used the extract the fringe direction to spin filtering of the original image. The algorithm can marked several targets in scanning process at the same time. So it has a high efficiency. The algorithm can be used in the multi-frequency heterodyne phase shift technology .And we can use the technology to complete the measurement of complex surfaces. Experimental results show that the method has a distinct advantage in measurement accuracy, measurement speed, and noise immunity.

Applications of High-Precise Three-Dimensional Measurement System

2011 ◽  
Vol 222 ◽  
pp. 62-65 ◽  
Author(s):  
Takeshi Hashimoto ◽  
Mitsuo Kaneko ◽  
András Rövid ◽  
Hiroaki Ohta ◽  
Akira Fukuda ◽  
...  
Keyword(s):  
Global Warming ◽  
Measurement System ◽  
Measurement Accuracy ◽  
Three Dimensional ◽  
Long Distance ◽  
Accuracy Measurement ◽  
Close Relationship ◽  
Three Dimensional Measurement ◽  
High Accuracy Measurement ◽  
Moving Speed

To reveal the influence of global warming on glaciers, highly accurate observations of glacier movement must continue every year. It is thought that there is a close relationship between glacier moving speed and global warming. Thus, there have been precise, detailed observations of the movement of the Perito Moreno glacier in Patagonia of the Argentine Republic over the past five years. The measurement method of using GPS and an optical measuring instrument is generally used to monitor glacier movement, but the measurement accuracy attained is not optimal because of the huge size of the glacier. The measurement system used for the Perito Moreno observations, however, could realize high accuracy measurement over long distance. The measurement system is based on the principle of stereo measurement using cameras. This paper describes the results of the Perito Moreno glacier observations of this year and considers the effectiveness of glacier observation using cameras.

Assumptions of Centering – Leveling Device Application in Mechatronic Angle Measuring System

2015 ◽  
Vol 220-221 ◽  
pp. 391-395
Author(s):  
Lauryna Šiaudinytė ◽  
Deividas Sabaitis ◽  
Mindaugas Rybokas ◽  
Domantas Bručas
Keyword(s):  
Measurement Accuracy ◽  
Angle Measurement ◽  
Measuring System ◽  
Measuring Systems ◽  
Measured Object ◽  
Preliminary Results ◽  
Device Application ◽  
Angle Measuring ◽  
Slight Movement ◽  
Further Development

This paper deals with the presentation of the new centering – leveling device developed in Vilnius Gediminas Technical University. Precision angle measuring systems are always combined of many mechanisms and devices which influence angle measurement accuracy. Therefore, every one of them has to be investigated separately. This device can be used as a separate device to perform a slight movement of measured object or it can be used as a part of mechatronic angle measuring system. This paper presents preliminary results of centering – leveling device minimum pitch determination and analysis of further development of this device as a part of mechatronic angle measuring system.

scholarly journals Portable Light Pen 3D Vision Coordinate Measuring System- Probe Tip Center Calibration

2013 ◽  
Vol 13 (4) ◽  
pp. 194-199 ◽  
Author(s):  
Shugui Liu ◽  
Hongling Zhang ◽  
Yinghua Dong ◽  
Shaliang Tang ◽  
Zhenzhu Jiang
Keyword(s):  
Accurate Determination ◽  
Least Square ◽  
Measuring System ◽  
Translation Vector ◽  
3D Vision ◽  
Fitting Method ◽  
Center Position ◽  
Tip Position ◽  
Light Pen

For different tasks, probe tip should be changed in the 3D vision coordinate measuring system and the accurate determination of probe tip center position is critical. A novel and simple approach for calibrating the probe tip center position of the light pen is presented in this paper. Hundreds of images of the light pen with different postures are collected while the probe tip is kept in firm contact with a reference conical hole. The probe tip position is determined by computing the rotation matrix and translation vector from the obtained images by using the least square fitting method. The experimental results demonstrate the effectiveness of the proposed approach. Its repeatability reaches 0.033 mm, 0.030 mm, and 0.043 mm in x, y, and z axes, respectively, and its convergence speed is satisfactory.

Research on Computational Method of Characteristic Parameters for Measuring System Based on Quasi-Static Absolute Calibration

2017 ◽  
Vol 865 ◽  
pp. 599-604
Author(s):  
Jing Chen ◽  
De Ren Kong ◽  
Ting Wei Gu ◽  
Fei Shang
Keyword(s):  
Measurement Accuracy ◽  
Computational Method ◽  
Measuring System ◽  
Effective Bandwidth ◽  
Absolute Calibration ◽  
Characteristic Parameters ◽  
Static Calibration ◽  
Force Transfer ◽  
Working Characteristic ◽  
Flat Section

Quasi-static absolute calibration is using force with semi-sinusoidal pulse to calibrate pressure measuring system. The pulse width must be wide enough in order to guarantee the effective bandwidth of frequency spectrum be in the flat section of amplitude-frequency characteristics of the tested system. In this way, the result is similar to that from static calibration. The working characteristic parameters for measuring system which is gained from quasi-static calibration is different form static calibration in species, physical meanings and attainment methods. Therefore, the research is of great significance in forming quasi-static calibration system and improving measurement accuracy. The pilot scheme will be introduced in this essay. What is more, the calculation of working characteristic parameters for measuring system will be discussed by taking the force with specific pulse as example, including sensitivity when force transfer to pressure, linearity and repeatability which are used to evaluate the uncertainty of measurement.

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