scholarly journals RESEARCH ON THE ACCURACY OF ANGLE MEASUREMENT / KAMPŲ MATAVIMO TIKSLUMO TYRIMAS

2012 ◽  
Vol 3 (6) ◽  
pp. 15-18 ◽  
Author(s):  
Artūras Prielaidas ◽  
Rimas Lazdinas
Keyword(s):  
Main Part ◽  
Measurement Accuracy ◽  
Angle Measurement ◽  
Rotary Disk

Rotary encoders are the main devices in industrial angle measurement. Accuracy is very important and is assured by the technology of manufacture. The main part (rotary disk) is under examination, and therefore a number of its characteristics are established and a comparison with the assembled encoder is presented. In conclusion, an error in the angle of the rotary disk makes a possibility of forecasting an error in the assembled encoder angle. Santrauka Nagrinėjamas limbų paklaidų matavimas, jų vertinimas, fotoelektrinių matavimų keitiklių paklaidų matavimas, bandoma nustatyti keitiklio paklaidų priklausomybę nuo limbo paklaidų. Pateikta limbų, keitiklių apžvalga, analizė, pagrindinės schemos. Atlikta limbų ir keitiklių paklaidų aproksimacija parametrinėmis funkcijomis. Apibendrinti visų matavimų rezultatai – kas būdinga paklaidų kreivėms, kokie dydžiai, jų aproksimacijos parametrinėmis funkcijomis rezultatai, formulės, analizė. Atlikti koreliacijos tarp limbo ir matavimo keitiklio paklaidų tyrimai.

scholarly journals Modifying Kinect placement to improve upper limb joint angle measurement accuracy

2016 ◽  
Vol 29 (4) ◽  
pp. 465-473 ◽  
Author(s):  
Na Jin Seo ◽  
Mojtaba F. Fathi ◽  
Pilwon Hur ◽  
Vincent Crocher
Keyword(s):  
Upper Limb ◽  
Measurement Accuracy ◽  
Joint Angle ◽  
Angle Measurement

scholarly journals Effectiveness of Variable-Gain Kalman Filter Based on Angle Error Calculated from Acceleration Signals in Lower Limb Angle Measurement with Inertial Sensors

2013 ◽  
Vol 2013 ◽  
pp. 1-12 ◽  
Author(s):  
Yuta Teruyama ◽  
Takashi Watanabe
Keyword(s):  
Kalman Filter ◽  
Lower Limb ◽  
Measurement Accuracy ◽  
Inertial Sensors ◽  
Angle Measurement ◽  
Angle Error ◽  
Variable Gain ◽  
Improve Measurement ◽  
Kalman Gain ◽  
Acceleration Signals

The wearable sensor system developed by our group, which measured lower limb angles using Kalman-filtering-based method, was suggested to be useful in evaluation of gait function for rehabilitation support. However, it was expected to reduce variations of measurement errors. In this paper, a variable-Kalman-gain method based on angle error that was calculated from acceleration signals was proposed to improve measurement accuracy. The proposed method was tested comparing to fixed-gain Kalman filter and a variable-Kalman-gain method that was based on acceleration magnitude used in previous studies. First, in angle measurement in treadmill walking, the proposed method measured lower limb angles with the highest measurement accuracy and improved significantly foot inclination angle measurement, while it improved slightly shank and thigh inclination angles. The variable-gain method based on acceleration magnitude was not effective for our Kalman filter system. Then, in angle measurement of a rigid body model, it was shown that the proposed method had measurement accuracy similar to or higher than results seen in other studies that used markers of camera-based motion measurement system fixing on a rigid plate together with a sensor or on the sensor directly. The proposed method was found to be effective in angle measurement with inertial sensors.

scholarly journals A Novel Vision-Based Pose Measurement Method Considering the Refraction of Light

Sensors ◽  
2018 ◽  
Vol 18 (12) ◽  
pp. 4348 ◽  
Author(s):  
Wei Liu ◽  
Xin Ma ◽  
Xiao Li ◽  
Yi Pan ◽  
Fuji Wang ◽  
...  
Keyword(s):  
Wind Tunnel ◽  
High Speed ◽  
Measurement Accuracy ◽  
Performance Testing ◽  
Angle Measurement ◽  
Normal Vector ◽  
Calibration Model ◽  
Linear Calibration ◽  
Observation Window ◽  
Vision Measurement

Nowadays, due to the advantages of non-contact and high-speed, vision-based pose measurements have been widely used for aircraft performance testing in a wind tunnel. However, usually glass ports are used to protect cameras against the high-speed airflow influence, which will lead to a big measurement error. In this paper, to further improve the vision-based pose measurement accuracy, an imaging model which considers the refraction light of the observation window was proposed. In this method, a nonlinear camera calibration model considering the refraction brought by the wind tunnel observation window, was established first. What’s more, a new method for the linear calibration of the normal vector of the glass observation window was presented. Then, combining with the proposed matching method based on coplanarity constraint, the six pose parameters of the falling target could be calculated. Finally, the experimental setup was established to conduct the pose measurement study in the laboratory, and the results satisfied the application requirements. Besides, experiments for verifying the vision measurement accuracy were also performed, and the results indicated that the displacement and angle measurement accuracy approximately increased by 57% and 33.6%, respectively, which showed the high accuracy of the proposed method.

scholarly journals Improvement of the Angle of Arrival Measurement Accuracy for Indoor UWB Localization

2020 ◽  
Vol 2020 ◽  
pp. 1-8
Author(s):  
N. Awarkeh ◽  
J.-C. Cousin ◽  
M. Muller ◽  
N. Samama
Keyword(s):  
Measurement Accuracy ◽  
Continuous Wave ◽  
Energy Detection ◽  
Angle Measurement ◽  
Phase Correlation ◽  
Ultra Wideband ◽  
Line Of Sight ◽  
Angle Of Arrival ◽  
Localization System ◽  
Classical Energy

This paper shows that the accuracy of azimuth angle measurement for an interferometric localization system used to locate tags in its Line-of-Sight (LoS) can be improved by exploiting Impulse Radio-Ultra WideBand (IR-UWB) signals and without increasing the frequency bandwidth. This solution uses a Phase Correlation (PC) method, initially applied for Continuous Wave (CW) signals, adapted for Ultra WideBand (UWB) pulse signals. The obtained results are compared to those computed by a classical Energy Detection (ED) method where it becomes impossible to estimate azimuth angles for tag positions close to the orthogonal centered axis of the localization system baseline.

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 Radiographic total disc replacement angle measurement accuracy using the Oxford Cobbometer: precision and bias

2008 ◽  
Vol 17 (8) ◽  
pp. 1066-1072 ◽  
Author(s):  
Victor Kosmopoulos ◽  
Kosmas Stafylas ◽  
John McManus ◽  
Constantin Schizas
Keyword(s):  
Measurement Accuracy ◽  
Total Disc Replacement ◽  
Angle Measurement ◽  
Disc Replacement

scholarly journals Compensation of Rotary Encoders Using Fourier Expansion-Back Propagation Neural Network Optimized by Genetic Algorithm

Sensors ◽  
2020 ◽  
Vol 20 (9) ◽  
pp. 2603 ◽  
Author(s):  
Hua-Kun Jia ◽  
Lian-Dong Yu ◽  
Yi-Zhou Jiang ◽  
Hui-Ning Zhao ◽  
Jia-Ming Cao
Keyword(s):  
Neural Network ◽  
Genetic Algorithm ◽  
Ambient Temperature ◽  
Bp Neural Network ◽  
Fourier Expansion ◽  
Measurement Accuracy ◽  
Back Propagation ◽  
Angle Measurement ◽  
Rotary Encoder ◽  
Measuring Machine

The measurement accuracy of the precision instruments that contain rotation joints is influenced significantly by the rotary encoders that are installed in the rotation joints. Apart from the imperfect manufacturing and installation of the rotary encoder, the variations of ambient temperature could cause the angle measurement error of the rotary encoder. According to the characteristics of the 2 π periodicity of the angle measurement at the stationary temperature and the complexity of the effects of ambient temperature changes, the method based on the Fourier expansion-back propagation (BP) neural network optimized by genetic algorithm (FE-GABPNN) is proposed to improve the angle measurement accuracy of the rotary encoder. The proposed method, which innovatively integrates the characteristics of Fourier expansion, the BP neural network and genetic algorithm, has good fitting performance. The rotary encoder that is installed in the rotation joint of the articulated coordinate measuring machine (ACMM) is calibrated by using an autocollimator and a regular optical polygon at ambient temperature ranging from 10 to 40 °C. The contrastive analysis is carried out. The experimental results show that the angle measurement errors decrease remarkably, from 110.2″ to 2.7″ after compensation. The mean root mean square error (RMSE) of the residual errors is 0.85″.

Absolute Calibration of the Rotary Encoder Considering the Influence on-Machine for Development of High-Speed Nanoprofiler

2012 ◽  
Vol 523-524 ◽  
pp. 842-846 ◽  
Author(s):  
Takuya Kojima ◽  
Koji Usuki ◽  
Takao Kitayama ◽  
Daisuke Tonaru ◽  
Hiroki Matsumura ◽  
...  
Keyword(s):  
High Speed ◽  
Measurement Accuracy ◽  
Angle Measurement ◽  
National Standard ◽  
Absolute Calibration ◽  
Normal Vector ◽  
Mirror Surface ◽  
Rotary Encoder ◽  
Aspheric Mirror ◽  
Method Of Measurement

The development of a high-speed nanoprofiler is essential for developing the next generation of ultraprecision aspheric mirrors. The purpose of this study is to develop a new high-speed nanoprofiler that traces the normal vector of an aspheric mirror surface. The method of measurement adopted here is based upon the accuracy of a rotation goniometer. In order to attain a form measurement accuracy of PV1nm, it is necessary to improve the angle measurement accuracy. In this study, we equip a nanoprofiler with a rotary encoder that is calibrated in order to accomplish this objective, using a national standard machine. Consequently, this rotary encoder can be calibrated with an accuracy of ±0.12 μrad when considering the influence of installing the encoder on the nanoprofiler.

Study on the Angle Measurement of Laser Shaft Alignment Instrument

2014 ◽  
Vol 898 ◽  
pp. 644-647
Author(s):  
Yao Lang ◽  
Dan Zheng ◽  
Xiu Yan Lv
Keyword(s):  
Measurement Accuracy ◽  
Measurement Data ◽  
Vertical Plane ◽  
Measurement Range ◽  
Angle Measurement ◽  
Measurement Point ◽  
Shaft Alignment ◽  
Conversion Formula

Laser shaft alignment instrument needs to know the angle which is rotated by the axis of measurement point at each time. It adopted the accelerometer ADXL203 to measure angle and put its two sensing axis in the vertical plane, and then calculated its outputs. It makes the conversion formula of inclination and acceleration better to improve the measurement accuracy, and the measurement range achieves 360 °. Finally, the measurement data dealt with mathematics are displayed by LabVIEW, and it friendly achieves the man-machine interactive function.

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