A New Method for Measuring Straightness and Yawing Motion Errors of a Linear Slide

2005 ◽  
Vol 128 (2) ◽  
pp. 503-512 ◽  
Author(s):  
Eric H. K. Fung
Keyword(s):  
Uncertainty Analysis ◽  
Frequency Domain ◽  
Measurement Method ◽  
Spatial Domain ◽  
Separation Technique ◽  
Profile Measurement ◽  
Motion Error ◽  
Sensor Reading ◽  
Error Separation ◽  
Linear Slide

In this paper, an on-machine Fourier five-sensor (F5S) measurement method is developed using Fourier series and sensor integration techniques to determine the straightness and yawing motion errors of a linear slide. The profile of the slide is also determined in this error separation technique. The method is an extension of the previous Fourier three-sensor (F3S) method (Fung, E. H. K., and Yang, S. M., 2000, “An Error Separation Technique for Measuring Straightness Motion Error of a Linear Slide,” Meas. Sci. Technol., 11, pp. 1515–1521; Yang, S. M., Fung, E. H. K., and Chiu, W. M., 2002, “Uncertainty Analysis of On-Machine Motion and Profile Measurement With Sensor Reading Errors,” Meas. Sci. Technol., 13, pp. 1937–1945) by including the effects of yawing error in the straightness motion error and profile measurements. The principles and operation of the F5S measurement method are described. The uncertainty analysis of the method in the presence of a sensor reading error is studied both in the frequency domain and the spatial domain. The spatial domain parameter is first optimized to yield the 12 possible sensor configurations and the final configuration is chosen based on the frequency domain parameter values. The method is evaluated by computer simulation where the simulated sensor outputs are derived from the predefined profile, straightness, and yawing motion errors. By comparing the calculated results with the input data, the F5S method is found to be superior to the F3S method as far as accuracy is concerned. The results reported in this simulation study not only confirm the feasibility of the F5S method but also encourage the author to perform an experimental study in the near future.

A New and High Precision Measurement Method of Spindle Rotation Induced Error and its Performance Research

2007 ◽  
Vol 10-12 ◽  
pp. 727-731 ◽  
Author(s):  
Z.C. Du ◽  
P. Zhang ◽  
Jian Guo Yang ◽  
M.S. Hong
Keyword(s):  
Frequency Domain ◽  
Measurement Method ◽  
Cnc Machine ◽  
Motion Error ◽  
Machining Center ◽  
Double Ball Bar ◽  
Spindle Rotation ◽  
Ball Bar ◽  
Measuring Experiment ◽  
The Cross

The accuracy of spindle rotation is one of the most important precision indexes of CNC machine tools. And the spindle rotation induced error is one of the main influence factors of cutting accuracy. It will greatly affect the shape precision and surface roughness of workpiece. A new measurement method of the spindle radial rotation induced error is proposed using the cross grid encoder. The Spindle rotation induced error of machining center is analyzed in frequency domain and time-frequency domain separately to comparably study the measurement results by KGM 182 grid encoder and Double ball bar. The results indicate that the performance of the cross grid encoder test for measuring the CNC machine tool motion error is better than that of the Double ball bar, especially in the details of motion errors because of its unique characteristics. A wavelet packet algorithm is developed to analyze the singularity of signal. On machine measuring experiment has been carried out on a new Cincinnati 750 Arrow II vertical machining center. The measuring experiment result shows that the spindle radial rotation induced error of the machining center is about 0.6 μm and the cycle time is every rotation time.

scholarly journals An Optical Frequency Domain Angle Measurement Method Based on Second Harmonic Generation

Sensors ◽  
2021 ◽  
Vol 21 (2) ◽  
pp. 670
Author(s):  
Wijayanti Dwi Astuti ◽  
Hiraku Matsukuma ◽  
Masaru Nakao ◽  
Kuangyi Li ◽  
Yuki Shimizu ◽  
...  
Keyword(s):  
Femtosecond Laser ◽  
Second Harmonic Generation ◽  
Frequency Domain ◽  
Harmonic Generation ◽  
Measurement Method ◽  
Second Harmonic ◽  
Angle Measurement ◽  
Laser Source ◽  
Optical Frequency ◽  
Measurable Range

This paper proposes a new optical angle measurement method in the optical frequency domain based on second harmonic generation with a mode-locked femtosecond laser source by making use of the unique characteristic of the high peak power and wide spectral range of the femtosecond laser pulses. To get a wide measurable range of angle measurement, a theoretical calculation for several nonlinear optical crystals is performed. As a result, LiNbO3 crystal is employed in the proposed method. In the experiment, the validity of the use of a parabolic mirror is also demonstrated, where the chromatic aberration of the focusing beam caused the localization of second harmonic generation in our previous research. Moreover, an experimental demonstration is also carried out for the proposed angle measurement method. The measurable range of 10,000 arc-seconds is achieved.

scholarly journals AUTOMATED MOSAICKING OF GEOSTATIONARY OCEAN COLOR IMAGER BY COMBINATION OF SPATIAL AND FREQUENCY MATCHING

2018 ◽  
Vol XLII-2 ◽  
pp. 495-499
Author(s):  
H. G. Kim ◽  
J. H. Son ◽  
T. Kim
Keyword(s):  
Frequency Domain ◽  
Spatial Domain ◽  
Geometric Distortion ◽  
Future Research ◽  
Geometric Correction ◽  
Frequency Matching ◽  
Image Mosaicking ◽  
Important Processing ◽  
Sensor Modelling

In general, image mosaicking is a useful and important processing for handling images with narrow field of view. It is being used widely for images from commercial cameras as well as from aerial and satellite cameras. For mosaicking images with geometric distortion, geometric correction of each image should be performed before combining images. However, automated mosaicking images with geometric distortion is not a trivial task. The goal of this paper is the development of automated mosaicking techniques applicable to handle GOCI images. In this paper, we try to extract tie-points by using spatial domain and frequency domain matching and perform the mosaicking of GOCI. The method includes five steps. First, we classify GOCI image slots according to the existence of shorelines by spatial domain matching. Second, we perform precise geometric correction on the slots with shorelines. Third, we perform initial sensor modelling for the slots without shorelines and apply geometric correction based on the initial model. Fourth, the relative relationship between the slots without shorelines and the slots with shorelines is estimated through frequency domain matching. Lastly, mosaicking of geometrically corrected all 16 image slots is performed. The proposed method was verified by applying to real GOCI images. The proposed method was able to perform automated mosaicking even for images without shorelines, and its accuracy and processing time were satisfactory. For future research, we will improve frequency matching to generate multiple tie-points and to analyse the applicability of precise sensor modelling directly from frequency matching. It is expected that the proposed method can be applied to the follow-up sensor of the GOCI, GOCI-II, and other ocean satellite images.

scholarly journals STUDI DAN IMPLEMENTASI STEGANOGRAFI METODE ALGORITMA DAN TRANSFORMASI PADA CITRA JPEG

Teknika ◽  
2013 ◽  
Vol 2 (1) ◽  
pp. 46-58
Author(s):  
Timothy John Pattiasina
Keyword(s):  
Frequency Domain ◽  
Wavelet Transformation ◽  
Spatial Domain ◽  
Discrete Cosine Transformation ◽  
Cosine Transformation

Steganografi adalah seni dan ilmu menulis atau menyemhunyikan pesan tersembunyi dengan suatu cara sehingga selain si pengirim dan si penerima, tidak ada seorangpun yang mengetahui atau menyadari bahwa ada suatu pesan rahasia. lstilah steganografi termasuk penyemhunyian data digital dalam komputer Ada beberapa metode steganografi, salah satunya adalah metode Algorithms and Transformation. Metode menyembunyikan data dalam fungsi matematika yang disebut algoritma compression. Dua fungsi tersebut adalah Discrete Cosine Transformation (DCT) dan Wavelet Transformation. Fungsi DCT dan Wavelet yaitu untuk mentransformasikan data dari satu tempat (domain) ke tempat (domain) yang lain. Fungsi DCT yaitu mentransformasi data dari tempat spatial (spatial domain) ke tempat fiekuensi (frequency domain).

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