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 Laser Ranging-Assisted Binocular Visual Sensor Tracking System

Sensors ◽  
2020 ◽  
Vol 20 (3) ◽  
pp. 688 ◽  
Author(s):  
Qilong Wang ◽  
Yu Zhang ◽  
Weichao Shi ◽  
Meng Nie
Keyword(s):  
Target Tracking ◽  
Binocular Vision ◽  
Measurement Accuracy ◽  
Mechanical Performance ◽  
Optical Axis ◽  
Tracking System ◽  
Laser Ranging ◽  
Visual Sensor ◽  
Vision Sensors ◽  
Federated Filtering

Aimed at improving the low measurement accuracy of the binocular vision sensor along the optical axis in the process of target tracking, we proposed a method for auxiliary correction using a laser-ranging sensor in this paper. In the process of system measurement, limited to the mechanical performance of the two-dimensional turntable, the measurement value of a laser-ranging sensor is lagged. In this paper, the lag information is updated directly to solve the time delay. Moreover, in order to give full play to the advantages of binocular vision sensors and laser-ranging sensors in target tracking, federated filtering is used to improve the information utilization and measurement accuracy and to solve the estimated correlation. The experimental results show that the real-time and measurement accuracy of the laser ranging-assisted binocular visual-tracking system is improved by the direct update algorithm and the federal filtering algorithm. The results of this paper are significant for binocular vision sensors and laser-ranging sensors in engineering applications involving target tracking systems.

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.

Research of Multi-Sensor Data Fusion Based on Binocular Vision Sensor and Laser Range Sensor

2016 ◽  
Vol 693 ◽  
pp. 1397-1404 ◽  
Author(s):  
Qi Long Wang ◽  
Jian Yong Li ◽  
Hai Kuo Shen ◽  
Teng Teng Song ◽  
Yan Xuan Ma
Keyword(s):  
Binocular Vision ◽  
Measurement Accuracy ◽  
Optical Axis ◽  
Vertical Direction ◽  
Utilization Efficiency ◽  
Sensor Data ◽  
Vision Sensor ◽  
Laser Range ◽  
Range Sensor ◽  
Sensor Information

The system of binocular vision sensor was used in the air-to-air close air target positioning in the paper. Due to the limitation of model itself, the measurement accuracy along the direction of optical axis is far lower than the accuracy of vertical direction. In order to improve the measurement accuracy of the optical axis, the paper put forward to using laser range sensor to cooperate with binocular vision sensor; Then the paper proposed adopts adaptive weighted fusion algorithm of multi-sensor information fusion to improve the utilization efficiency of multi-sensor information and to make the results accurately; Finally, the parameters of the system were calibration respectively and experiment is simulated, experimental results show that the position system is feasibility and effectiveness.

scholarly journals Effects of Loading and Boundary Conditions on the Performance of Ultrasound Compressional Viscoelastography: A Computational Simulation Study to Guide Experimental Design

Materials ◽  
2021 ◽  
Vol 14 (10) ◽  
pp. 2590
Author(s):  
Che-Yu Lin ◽  
Ke-Vin Chang
Keyword(s):  
Boundary Conditions ◽  
Simulation Study ◽  
Viscoelastic Properties ◽  
Measurement Accuracy ◽  
Computational Simulation ◽  
Vertical Direction ◽  
Fixation Method ◽  
Element Analysis ◽  
Sample Container

Most biomaterials and tissues are viscoelastic; thus, evaluating viscoelastic properties is important for numerous biomedical applications. Compressional viscoelastography is an ultrasound imaging technique used for measuring the viscoelastic properties of biomaterials and tissues. It analyzes the creep behavior of a material under an external mechanical compression. The aim of this study is to use finite element analysis to investigate how loading conditions (the distribution of the applied compressional pressure on the surface of the sample) and boundary conditions (the fixation method used to stabilize the sample) can affect the measurement accuracy of compressional viscoelastography. The results show that loading and boundary conditions in computational simulations of compressional viscoelastography can severely affect the measurement accuracy of the viscoelastic properties of materials. The measurement can only be accurate if the compressional pressure is exerted on the entire top surface of the sample, as well as if the bottom of the sample is fixed only along the vertical direction. These findings imply that, in an experimental validation study, the phantom design should take into account that the surface area of the pressure plate must be equal to or larger than that of the top surface of the sample, and the sample should be placed directly on the testing platform without any fixation (such as a sample container). The findings indicate that when applying compressional viscoelastography to real tissues in vivo, consideration should be given to the representative loading and boundary conditions. The findings of the present simulation study will provide a reference for experimental phantom designs regarding loading and boundary conditions, as well as guidance towards validating the experimental results of compressional viscoelastography.

Effects of shoulder translation on lumbar moment for two dimensional modeling strategies during lifting

1998 ◽  
Vol 1 (3) ◽  
pp. 173-187
Author(s):  
Wayne J. Albert ◽  
Joan M. Stevenson ◽  
Geneviève A. Dumas ◽  
Roger W. Wheeler
Keyword(s):  
Sagittal Plane ◽  
Tracking System ◽  
Vertical Direction ◽  
Two Dimensional ◽  
Model Type ◽  
Trunk Acceleration ◽  
Analysis System ◽  
Trunk Orientation ◽  
Shoulder Position ◽  
Dynamic Link

The objectives of this study were to: 1) develop a dynamic 2D link segment model for lifting using the constraints of four sensors from an electromagnetic motion analysis system; 2) evaluate the magnitude of shoulder movement in the sagittal plane during lifting; and 3) investigate the effect of shoulder translation on trunk acceleration and lumbar moments calculated by the developed model and comparing it with two separate 2D dynamic link segment models. Six women and six men lifted loads of 2 kg, 7 kg, 12 kg and 2 kg, 12 kg, 22 kg respectively, under stoop, squat and freestyle conditions. Trunk orientation and position, as well as shoulder position were monitored during all lifts using the Polhemus FASTRAK\trdmk. Results indicated that average range of motion was 0.05 ± 0.02 m in the horizontal direction and 0.03 ± 0.02 m in the vertical direction. Shoulder position relative to T1 was located 0.07 ± 0.02 m anteriorly, and 0.02 ± 0.04 m superiorly (0.06 and 0.00 m for males and 0.08 and 0.04 m for females, respectively). To estimate the effect of shoulder motion on trunk acceleration and L5/S1 moments, three two-dimensional dynamic link segment models were developed within the constraints of the electromagnetic tracking system and compared. Trunk segment endpoints were defined as L5/S1 and either T1 or shoulder depending on model type. For trunk accelerations, average differences between models were greater than 40 deg/s² in 70.4% trunk accelerations did not translate into significantly different moment calculations between models. Average peak dynamic L5/S1 moment differences between models were smaller than 4 Nm for all lifting conditions which failed to be statistically significant (p>0.05). The model type did not have a statistically significant effect on peak L5/S1 moments. Therefore, despite important shoulder joint translations, peak L5/S1 moments were not significantly affected.

scholarly journals In Vitro and In Vivo Assessment of a New Workflow for the Acquisition of Mandibular Kinematics Based on Portable Tracking System with Passive Optical Reflective Markers

2021 ◽  
Vol 11 (9) ◽  
pp. 3947
Author(s):  
Marco Farronato ◽  
Gianluca M. Tartaglia ◽  
Cinzia Maspero ◽  
Luigi M. Gallo ◽  
Vera Colombo
Keyword(s):  
Measurement Error ◽  
Tracking System ◽  
Intraclass Correlation ◽  
Optical Tracking ◽  
Optical Tracking System ◽  
Rater Reliability ◽  
Tracking Device ◽  
Mandibular Kinematics

Clinical use of portable optical tracking system in dentistry could improve the analysis of mandibular movements for diagnostic and therapeutic purposes. A new workflow for the acquisition of mandibular kinematics was developed. Reproducibility of measurements was tested in vitro and intra- and inter-rater repeatability were assessed in vivo in healthy volunteers. Prescribed repeated movements (n = 10) in three perpendicular directions of the tracking-device coordinate system were performed. Measurement error and coefficient of variation (CV) among repetitions were determined. Mandibular kinematics of maximum opening, left and right laterality, protrusion and retrusion of five healthy subjects were recorded in separate sessions by three different operators. Obtained records were blindly examined by three observers. Intraclass correlation coefficient (ICC) was calculated to estimate inter-rater and intra-rater reliability. Maximum in vitro measurement error was 0.54 mm and CV = 0.02. Overall, excellent intra-rater reliability (ICC > 0.90) for each variable, general excellent intra-rater reliability (ICC = 1.00) for all variables, and good reliability (ICC > 0.75) for inter-rater tests were obtained. A lower score was obtained for retrusion with “moderate reliability” (ICC = 0.557) in the inter-rater tests. Excellent repeatability and reliability in optical tracking of primary movements were observed using the tested portable tracking device and the developed workflow.

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