scholarly journals Research on Target Deviation Measurement of Projectile Based on Shadow Imaging Method in Laser Screen Velocity Measuring System

Sensors ◽  
2020 ◽  
Vol 20 (2) ◽  
pp. 554 ◽  
Author(s):  
Wenbo Chu ◽  
Donge Zhao ◽  
Baowei Liu ◽  
Bin Zhang ◽  
Zhiguo Gui
Keyword(s):  
High Speed ◽  
Target Position ◽  
Measuring System ◽  
Laser Source ◽  
Imaging Method ◽  
Aspherical Lens ◽  
Timing Pulse ◽  
Shadow Imaging ◽  
Deviation Measurement ◽  
Velocity Measuring

In the laser screen velocity measuring (LSVM) system, there is a deviation in the consistency of the optoelectronic response between the start light screen and the stop light screen. When the projectile passes through the light screen, the projectile’s over-target position, at which the timing pulse of the LSVM system is triggered, deviates from the actual position of the light screen (i.e., the target deviation). Therefore, it brings errors to the measurement of the projectile’s velocity, which has become a bottleneck, affecting the construction of a higher precision optoelectronic velocity measuring system. To solve this problem, this paper proposes a method based on high-speed shadow imaging to measure the projectile’s target deviation, ΔS, when the LSVM system triggers the timing pulse. The infrared pulse laser is collimated by the combination of the aspherical lens to form a parallel laser source that is used as the light source of the system. When the projectile passes through the light screen, the projectile’s over-target signal is processed by the specially designed trigger circuit. It uses the rising and falling edges of this signal to trigger the camera and pulsed laser source, respectively, to ensure that the projectile’s over-target image is adequately exposed. By capturing the images of the light screen of the LSVM system and the over-target projectile separately, this method of image edge detection was used to calculate the target deviation, and this value was used to correct the target distance of the LSVM to improve the accuracy of the measurement of the projectile’s velocity.

scholarly journals An Application of the Visualization Methods for Investigation Small Scale Processes in the Atmosphere-hydrosphere Boundary Layer within Laboratory Experiments on the Wind-wave Facilities

2021 ◽  
Author(s):  
Daniil Sergeev ◽  
Anatoly Suvorov ◽  
Alexander Kandaurov
Keyword(s):  
Boundary Layer ◽  
High Speed ◽  
Wind Wave ◽  
Weather Conditions ◽  
Optical Methods ◽  
Small Scale ◽  
Imaging Method ◽  
Shadow Imaging ◽  
Laboratory Modelling ◽  
The Waves

Hydro/aerodynamic laboratory experiment aimed at the laboratory modelling of the physical processes marine atmospheric boundary layer is one of the most complicated. Especial features as spray of droplets, the bubbles in the water and foam generated during the breaking of the waves should be taken into account when modelling extreme weather conditions caused by severe winds. Thus, in the experiment we are dealing with a multiphase turbulent flow with a free boundary. This investigation describes developing approaches to the use of optical methods based on visualization for performing these investigations. Presented results were obtained in experiments carried out on wind-wave facilities. To study the processes of fragmentation of the water surface leading to the formation of droplets and foam, high-speed multi-angle video taking is used in combination with the shadow imaging method.

A Study on Velocity Decay of φ6mm Tungsten Ball Fragment

2014 ◽  
Vol 1042 ◽  
pp. 154-158
Author(s):  
Chun Lin Yi ◽  
De Ren Kong ◽  
Yi Zhao Li ◽  
Li Ping Li ◽  
Jin Qiu Zhang ◽  
...  
Keyword(s):  
High Speed ◽  
Least Square Method ◽  
Least Square ◽  
Experimental Results ◽  
Measuring System ◽  
Low Speed ◽  
Velocity Decay ◽  
Velocity Attenuation ◽  
Attenuation Models ◽  
Velocity Measuring

In order to explore the velocity attenuation law and model of φ6mm tungsten ball fragment, theory analysis combined with tests is employed to study its velocity experimental results. First of all, a fragment velocity measuring system including 12 groups of cutting device is established. Then the attenuation experiments of φ6mm tungsten ball fragment in high speed and low speed velocity are performed by the measuring system. Based on the least-square method, MATLAB software is adopted to analysis the experimental data and obtained the high speed and low speed velocity attenuation models. The results show that φ6mm tungsten ball fragment speed attenuation coefficient is consistent in high speed and low. Thus, the analysis on velocity experimental results verifies that the established model is reasonable.

scholarly journals Investigation of the bag-breakup phenomena of the spray generation processes during wind-wave interaction in the laboratory experiments with optical methods

2021 ◽  
Vol 2127 (1) ◽  
pp. 012015
Author(s):  
A A Kandaurov ◽  
D A Sergeev ◽  
Yu I Troitskaya
Keyword(s):  
High Speed ◽  
Laboratory Experiments ◽  
Wind Wave ◽  
Wave Interaction ◽  
Optical Methods ◽  
Imaging Method ◽  
Thin Membrane ◽  
Spray Formation ◽  
High Speed Video ◽  
Shadow Imaging

Abstract Present paper devoted to the investigations with optical methods processes of artificially induced bag-breakup type of spray formation phenomenon within wind-wave interaction. Experiments were carried out on the Thermostratified Wind-Wave Tank of the IAP RAS. High-speed video filming with the shadow imaging method demonstrated that it was possible to artificially reproduce all the main stages of this phenomenon, which are also observed for the sporadically occurred ones: inflation of a thin membrane surrounded by a thicker rim, rupture of the membrane leading to the formation of small droplets, fragmentation of the rim with the formation of large droplets. Special processing of the images allowed us to estimate typical lifetimes and sizes of membrane for artificial bag-breakup events which turned out to be close to the same parameters for sporadically occurred ones.

Study of Velocity Measurement Error Analysis and Improving Velocity Measurement Accuracy on High-Speed Train

2014 ◽  
Vol 596 ◽  
pp. 468-471
Author(s):  
Tao Hou ◽  
Duo Wang Fan ◽  
Hong Xia Niu
Keyword(s):  
Measurement Error ◽  
Error Analysis ◽  
Velocity Measurement ◽  
High Speed ◽  
Measurement Method ◽  
Measurement Accuracy ◽  
Measuring System ◽  
High Speed Train ◽  
Speed Measurement ◽  
Velocity Measuring

For the problem of a big velocity measurement error,analyzed the velocity measurement error and studied the method of improving velocity measurement accuracy for the velocity measuring system of high-speed train.In this analysis and method, the speed error analysis was carried out based on understand the characteristics of the high-speed train speed sensor, and found that there is a bigger error. Then discussed the influence of large errors of the control system, and then put forward the improved M/T speed measurement method to solve the error problem. Finally, calculated velocity-measuring error for the improved M/T speed measurement method. The results show that the accuracy of speed has improved greatly. The research method can improve the accuracy to meet the requiring of train safety and smooth run.

scholarly journals High-speed volumetric two-photon fluorescence imaging of neurovascular dynamics

2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Jiang Lan Fan ◽  
Jose A. Rivera ◽  
Wei Sun ◽  
John Peterson ◽  
Henry Haeberle ◽  
...  
Keyword(s):  
Blood Flow ◽  
High Speed ◽  
Laser Scanning ◽  
Three Dimensional ◽  
Laser Scanning Microscopy ◽  
Fluorescence Signal ◽  
Imaging Method ◽  
Spatiotemporal Resolution ◽  
Two Photon

AbstractUnderstanding the structure and function of vasculature in the brain requires us to monitor distributed hemodynamics at high spatial and temporal resolution in three-dimensional (3D) volumes in vivo. Currently, a volumetric vasculature imaging method with sub-capillary spatial resolution and blood flow-resolving speed is lacking. Here, using two-photon laser scanning microscopy (TPLSM) with an axially extended Bessel focus, we capture volumetric hemodynamics in the awake mouse brain at a spatiotemporal resolution sufficient for measuring capillary size and blood flow. With Bessel TPLSM, the fluorescence signal of a vessel becomes proportional to its size, which enables convenient intensity-based analysis of vessel dilation and constriction dynamics in large volumes. We observe entrainment of vasodilation and vasoconstriction with pupil diameter and measure 3D blood flow at 99 volumes/second. Demonstrating high-throughput monitoring of hemodynamics in the awake brain, we expect Bessel TPLSM to make broad impacts on neurovasculature research.

A High Speed and Ultra Long-Haul Radio-Over-Fiber System Employing Dual Photoelectric Arms Coherent Modulation and Optical Duo-Binary Coding

2014 ◽  
Vol 988 ◽  
pp. 544-547
Author(s):  
Guang Li
Keyword(s):  
High Speed ◽  
Continuous Wave ◽  
Single Mode ◽  
Fiber Amplifier ◽  
Radio Over Fiber ◽  
Laser Source ◽  
Signal Spectrum ◽  
Fiber System ◽  
Binary Coding ◽  
Coherent Modulation

A novel high speed and ultra long-haul radio-over-fiber (ROF) system based on Dual Photoelectric Arms Coherent Modulation (DPACM) and Optical Duo-Binary Coding (ODBC) is proposed, and demonstrated. The signal spectrum bandwidth, generated by ODBC based on the first order DPACM, is half of non-return-to-zero (NRZ ) signal spectrum bandwidth. The secondary order DPACM generates a 40-GHz Millimeter-wave (mm-wave) that is transmitted over fiber (ROF). The simulation results show that, the bit rate can be up to 40 Gbps and the transmission distance is over 1500 Km, based on the ROF system with a 0 dBm continuous-wave laser source, multiple stages Er-Doped Fiber Amplifier (EDFA), a standard single mode fiber (SSMF) with a dispersion of 17 ps/nm/Km and a attenuation of 0.2 dB/Km.

Investigations on the positioning accuracy of the Nano Fabrication Machine (NFM-100)

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Jaqueline Stauffenberg ◽  
Ingo Ortlepp ◽  
Ulrike Blumröder ◽  
Denis Dontsov ◽  
Christoph Schäffel ◽  
...  
Keyword(s):  
Target Position ◽  
Repeated Measurements ◽  
Scanning Probe ◽  
Measuring System ◽  
Direct Drive ◽  
Positioning Accuracy ◽  
Scanning Probe Lithography ◽  
Nano Fabrication ◽  
Atomic Force ◽  
Acceleration And Deceleration

Abstract This contribution deals with the analysis of the positioning accuracy of a new Nano Fabrication Machine. This machine uses a planar direct drive system and has a positioning range up to 100 mm in diameter. The positioning accuracy was investigated in different movement scenarios, including phases of acceleration and deceleration. Also, the target position error of certain movements at different positions of the machine slider is considered. Currently, the NFM-100 is equipped with a tip-based measuring system. This Atomic Force Microscope (AFM) uses self-actuating and self-sensing microcantilevers, which can be used also for Field-Emission-Scanning-Probe-Lithography (FESPL). This process is capable of fabricating structures in the range of nanometres. In combination with the NFM-100 and its positioning range, nanostructures can be analysed and written in a macroscopic range without any tool change. However, the focus in this article is on the measurement and positioning accuracy of the tip-based measuring system in combination with the NFM-100 and is verified by repeated measurements. Finally, a linescan, realised using both systems, is shown over a long range of motion of 30 mm.

scholarly journals Redesigned Sensor Holder for an Atomic Force Microscope with an Adjustable Probe Direction

2021 ◽  
Author(s):  
Janik Schaude ◽  
Maxim Fimushkin ◽  
Tino Hausotte
Keyword(s):  
Atomic Force Microscope ◽  
Piezoelectric Actuator ◽  
High Speed ◽  
Closed Loop ◽  
Coefficient Of Thermal Expansion ◽  
Measuring System ◽  
Contact Mode ◽  
Loop Control ◽  
Atomic Force ◽  
Measuring Machine

AbstractThe article presents a redesigned sensor holder for an atomic force microscope (AFM) with an adjustable probe direction, which is integrated into a nano measuring machine (NMM-1). The AFM, consisting of a commercial piezoresistive cantilever operated in closed-loop intermitted contact-mode, is based on two rotational axes, which enable the adjustment of the probe direction to cover a complete hemisphere. The axes greatly enlarge the metrology frame of the measuring system by materials with a comparatively high coefficient of thermal expansion. The AFM is therefore operated within a thermostating housing with a long-term temperature stability of 17 mK. The sensor holder, connecting the rotational axes and the cantilever, inserted one adhesive bond, a soldered connection and a geometrically undefined clamping into the metrology circle, which might also be a source of measurement error. It has therefore been redesigned to a clamped senor holder, which is presented, evaluated and compared to the previous glued sensor holder within this paper. As will be shown, there are no significant differences between the two sensor holders. This leads to the conclusion, that the three aforementioned connections do not deteriorate the measurement precision, significantly. As only a minor portion of the positioning range of the piezoelectric actuator is needed to stimulate the cantilever near its resonance frequency, a high-speed closed-loop control that keeps the cantilever within its operating range using this piezoelectric actuator further on as actuator was implemented and is presented within this article.

Measurement and Analysis on Transient Thermal Characteristics of High Speed Motorized Spindle

2011 ◽  
Vol 52-54 ◽  
pp. 2021-2026
Author(s):  
Gui Ling Deng ◽  
Can Zhou
Keyword(s):  
High Speed ◽  
Thermal Deformation ◽  
Thermal Characteristics ◽  
Measuring System ◽  
Test Results ◽  
Motorized Spindle ◽  
Measurement And Analysis ◽  
Turning Center ◽  
Transient Thermal ◽  
Deformation Compensation

Thermal deformation is an important factor to affect the accuracy of the motorized spindle, the core component of high-speed machine tool. To understand the spindle system transient thermal characteristics of the high-speed turning center CH7516GS, some high-precision sensors and high-frequency data acquisition system is used to establish the temperature and displacement measuring system. The thermal deformation compensation model is established on the basis of the experimental test results.

Multiple CMOS Intersection Measuring System Modeling and Analysis

2012 ◽  
Vol 614-615 ◽  
pp. 1299-1302
Author(s):  
Ming Jing Li ◽  
Yu Bing Dong ◽  
Guang Liang Cheng
Keyword(s):  
High Speed ◽  
High Performance ◽  
High Reliability ◽  
System Modeling ◽  
Position Effect ◽  
Field Of View ◽  
Measuring System ◽  
Price Ratio ◽  
Matlab Simulation ◽  
Modeling And Analysis

Multiple high speed CMOS cameras composing intersection system to splice large effect field of view(EFV). The key problem of system is how to locate multiple CMOS cameras in suitable position. Effect field of view was determined according to size, quantity and dispersion area of objects, so to determine camera position located on below, both sides and ahead to moving targets. This paper analyzes effect splicing field of view, operating range etc through establishing mathematical model and MATLAB simulation. Location method of system has advantage of flexibility splicing, convenient adjustment, high reliability and high performance-price ratio.

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