scholarly journals A New Method of Angle Measurement Error Analysis of Rotary Encoders

2019 ◽  
Vol 9 (16) ◽  
pp. 3415 ◽  
Author(s):  
Hua-Kun Jia ◽  
Lian-Dong Yu ◽  
Hui-Ning Zhao ◽  
Yi-Zhou Jiang
Keyword(s):  
Measurement Error ◽  
Measurement Accuracy ◽  
Angle Measurement ◽  
Error Model ◽  
Source Analysis ◽  
Measuring Instruments ◽  
Rotating Shaft ◽  
Radial Error ◽  
Precision Measuring ◽  
Error Motion

In this article, a method of error source analysis and detection to improve the angle measurement accuracy of rotary encoders in precision measuring instruments is proposed. The angle measurement error caused by the installation eccentricity of the grating disk and the radial error motion of the rotating shaft is analyzed, and the error model is built. The method of measuring the radial error motion is introduced, and the visual system and image processing technology is proposed to detect the eccentricity. The verification experiment by the use of an autocollimator and a polygon is carried out. The residual error after comparison within ±6″ accounts for 9% of the angle measurement error. The proposed error model is verified, and the angle measurement error can be predicted if the installation eccentricity and radial error motion are known.

scholarly journals Research on Measurement Accuracy of Laser Tracking System Based on Spherical Mirror with Rotation Errors of Gimbal Mount Axes

2018 ◽  
Vol 18 (1) ◽  
pp. 13-19 ◽  
Author(s):  
Zhaoyao Shi ◽  
Huixu Song ◽  
Hongfang Chen ◽  
Yanqiang Sun
Keyword(s):  
Measurement Error ◽  
Measurement Accuracy ◽  
Optical Axis ◽  
Tracking System ◽  
Vertical Direction ◽  
Laser Ranging ◽  
Spherical Mirror ◽  
Laser Tracking ◽  
Radial Error ◽  
Error Motion

Abstract This paper presents a novel experimental approach for confirming that spherical mirror of a laser tracking system can reduce the influences of rotation errors of gimbal mount axes on the measurement accuracy. By simplifying the optical system model of laser tracking system based on spherical mirror, we can easily extract the laser ranging measurement error caused by rotation errors of gimbal mount axes with the positions of spherical mirror, biconvex lens, cat’s eye reflector, and measuring beam. The motions of polarization beam splitter and biconvex lens along the optical axis and vertical direction of optical axis are driven by error motions of gimbal mount axes. In order to simplify the experimental process, the motion of biconvex lens is substituted by the motion of spherical mirror according to the principle of relative motion. The laser ranging measurement error caused by the rotation errors of gimbal mount axes could be recorded in the readings of laser interferometer. The experimental results showed that the laser ranging measurement error caused by rotation errors was less than 0.1 μm if radial error motion and axial error motion were within ±10 μm. The experimental method simplified the experimental procedure and the spherical mirror could reduce the influences of rotation errors of gimbal mount axes on the measurement accuracy of the laser tracking system.

scholarly journals Research on Ground Calibration Technology for Geomagnetism Sensors

2018 ◽  
Vol 153 ◽  
pp. 07002 ◽  
Author(s):  
Zhang Hui ◽  
Li Chuanjun ◽  
Liu Yukuan
Keyword(s):  
Measurement Error ◽  
Measurement Accuracy ◽  
Least Square Method ◽  
Error Model ◽  
Least Square ◽  
Paper Analyse ◽  
Environment Factors ◽  
Sensor Error ◽  
Calibration Algorithm ◽  
Ground Calibration

The measurements of geomagnetism sensors are often affected by self-factors, install-factors and environment factors, therefore they often exist error and cause measurement accuracy reduction. Focus on these problems, this paper analyse existing ground calibration algorithms and their merits and demerits respectively. Besides, a comprehensive geomagnetism sensor error model is presented. Based on this model, a least square method based ellipsoid fitting calibration and compensation algorithm is presented. The experiment results show that this novel calibration algorithm can effectively restrain and compensate geomagnetism signal measurement error.

scholarly journals 2D Rotation-Angle Measurement Utilizing Least Iterative Region Segmentation

Sensors ◽  
2019 ◽  
Vol 19 (7) ◽  
pp. 1634 ◽  
Author(s):  
Chenguang Cao ◽  
Qi Ouyang
Keyword(s):  
Measurement Error ◽  
Measurement Accuracy ◽  
Rotation Angle ◽  
Correction Method ◽  
Angle Measurement ◽  
Geometric Moments ◽  
Automatic Sorting ◽  
Camera Pose ◽  
Sorting System ◽  
Accuracy Speed

When geometric moments are used to measure the rotation-angle of plane workpieces, the same rotation angle would be obtained with dissimilar poses. Such a case would be shown as an error in an automatic sorting system. Here, we present an improved rotation-angle measurement method based on geometric moments, which is suitable for automatic sorting systems. The method can overcome this limitation to obtain accurate results. The accuracy, speed, and generality of this method are analyzed in detail. In addition, a rotation-angle measurement error model is established to study the effect of camera pose on the rotation-angle measurement accuracy. We find that a rotation-angle measurement error will occur with a non-ideal camera pose. Thus, a correction method is proposed to increase accuracy and reduce the measurement error caused by camera pose. Finally, an automatic sorting system is developed, and experiments are conducted to verify the effectiveness of our methods. The experimental results show that the rotation angles are accurately obtained and workpieces could be correctly placed by this system.

scholarly journals Strategy to Decrease the Angle Measurement Error Introduced by the Use of Circular Grating in Dynamic Torque Calibration

Sensors ◽  
2021 ◽  
Vol 21 (22) ◽  
pp. 7599
Author(s):  
Yongbin Du ◽  
Feng Yuan ◽  
Zongze Jiang ◽  
Kai Li ◽  
Shuiwang Yang ◽  
...  
Keyword(s):  
Measurement Error ◽  
Second Harmonic ◽  
Total Error ◽  
Angle Measurement ◽  
Error Model ◽  
High Precision Measurement ◽  
Single Reading ◽  
Compensation Methods ◽  
Circular Grating ◽  
Eccentricity Error

A circular grating angle encoder is a key component in the dynamic torque calibration system. To improve the accuracy of an angle measurement, in this paper, the source of the angle measurement error of the circular grating is analyzed; an eccentricity error model and an inclination error model are proposed, respectively; further, these two models are combined to establish a total error model. Through the simulation study with the models, the conditions, in which the eccentricity error or inclination error can be ignored, are discussed. The calibration and compensation methods of the angle measurement error are given, and a progressive error compensation function which integrates the first harmonic fitting and the second harmonic fitting is obtained. An experiment is performed to verify the proposed calibration and compensation methods. The peak-to-peak value of the compensated angle measurement error of the single reading head can be reduced by about 93.76%, which approximates to the error of the mean value of the double reading heads. The experimental results show that the error calibration and compensation method based on the proposed error model can effectively compensate the angle measurement error of the circular grating with a single reading head, and obtain a high-precision measurement angle.

A Novel Compensation Method for Time-Grating Sensor’s Dynamic Measurement Error

2014 ◽  
Vol 644-650 ◽  
pp. 1278-1281
Author(s):  
Shi Zheng Sun ◽  
Dong Lin Peng ◽  
Fang Yan Zheng
Keyword(s):  
Measurement Error ◽  
Measurement Accuracy ◽  
Least Square Method ◽  
Dynamic Measurement ◽  
Compensation Method ◽  
Least Square ◽  
Mechanical Processing ◽  
Accuracy Analysis ◽  
Optimal Parameters ◽  
Precision Measuring

In order to improve time-grating sensor’s measurement accuracy, which is influenced by stability of the components, temperature and mechanical processing in precision measuring procedure. A novel compensation method based on Fourier series approach and least square is presented. With this method, the measurement error is separate into a lot of harmonics, and the optimal parameters of compensation are evaluated by least square method. The accuracy analysis certificates that time-grating sensor’s measurement error is reduced from ±14.8′′ to ±2.5′′ by applying the error compensation method, which is compensated about 80% compared with no compensation. Sensor’s accuracy is effectively improved.

scholarly journals Rotating Shaft Tilt Angle Measurement Using an Inclinometer

2015 ◽  
Vol 15 (5) ◽  
pp. 236-243 ◽  
Author(s):  
Jun Luo ◽  
Zhiqian Wang ◽  
Chengwu Shen ◽  
Zhuoman Wen ◽  
Shaojin Liu ◽  
...  
Keyword(s):  
Standard Deviation ◽  
Tilt Angle ◽  
Measurement Method ◽  
Measurement Accuracy ◽  
Angle Measurement ◽  
Uncertainty Estimation ◽  
Rotating Shaft ◽  
Rotating Machine ◽  
High Measurement ◽  
High Measurement Accuracy

AbstractThis paper describes a novel measurement method to accurately measure the rotating shaft tilt angle of rotating machine for alignment or compensation using a dual-axis inclinometer. A model of the rotating shaft tilt angle measurement is established using a dual-axis inclinometer based on the designed mechanical structure, and the calculation equation between the rotating shaft tilt angle and the inclinometer axes outputs is derived under the condition that the inclinometer axes are perpendicular to the rotating shaft. The reversal measurement method is applied to decrease the effect of inclinometer drifts caused by temperature, to eliminate inclinometer and rotating shaft mechanical error and inclinometer systematic error to attain high measurement accuracy. The uncertainty estimation shows that the accuracy of rotating shaft tilt angle measurement depends mainly on the inclinometer uncertainty and its uncertainty is almost the same as the inclinometer uncertainty in the simulation. The experimental results indicate that measurement time is 4 seconds; the range of rotating shaft tilt angle is 0.002° and its standard deviation is 0.0006° using NS-5/P2 inclinometer, whose precision and resolution are ±0.01° and 0.0005°, respectively.

Internal Vibration Source Analysis of AMB-Rotor System in HTR-PM Primary Helium Circulator

2018 ◽  
Author(s):  
Jinpeng Yu ◽  
Lei Zhao
Keyword(s):  
Measurement Error ◽  
Magnetic Anisotropy ◽  
Measurement Accuracy ◽  
Magnetic Bearing ◽  
Rotor System ◽  
Displacement Measurement ◽  
Active Magnetic Bearing ◽  
Field Analysis ◽  
Source Analysis ◽  
Vibration Source

The active magnetic bearing (AMB) in HTR-PM primary helium circulator (PHC) applies the inductive displacement transducer (IDT) to achieve the closed-loop feedback control. The magnetic anisotropy of the rotor material can be equivalent to structure defect of the rotor and affect the IDT measurement accuracy, leading to internal exciting vibration of the rotor. In this paper, the magnetic field analysis shows that the rotor magnetic anisotropy has effect on the sensor measurement and brings about the displacement measurement error. In the rotor-sensor experiment, the effect of rotor magnetic anisotropy on the IDT is obtained as a curve of magnetic error, which further explains that the rotor magnetic anisotropy will affect the dynamic measurement accuracy of the IDT. With the simulation result, it is observed that the displacement measurement error will lead to the internal exciting force of AMB-rotor system. The force will increase as the rotor speed increases, and bring about high-frequency vibration of the rotor.

Mathematical simulation of error functions of decision-making at tolerance control of measuring techniques availability

Metrologiya ◽  
2020 ◽  
pp. 3-15
Author(s):  
Rustam Z. Khayrullin ◽  
Alexey S. Kornev ◽  
Andrew A. Kostoglotov ◽  
Sergey V. Lazarenko
Keyword(s):  
Measurement Error ◽  
Geometric Interpretation ◽  
Measuring Instruments ◽  
Measured Quantity ◽  
Metrological Examination ◽  
Technical Documentation ◽  
Error Functions ◽  
Measuring Techniques ◽  
Tolerance Control ◽  
Laws Of Distribution

Analytical and computer models of false failure and undetected failure (error functions) were developed with tolerance control of the parameters of the components of the measuring technique. A geometric interpretation of the error functions as two-dimensional surfaces is given, which depend on the tolerance on the controlled parameter and the measurement error. The developed models are applicable both to theoretical laws of distribution, and to arbitrary laws of distribution of the measured quantity and measurement error. The results can be used in the development of metrological support of measuring equipment, the verification of measuring instruments, the metrological examination of technical documentation and the certification of measurement methods.

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