scholarly journals Sinusoidal Phase-Modulated Angle Interferometer for Angular Vibration Measurement

Sensors ◽  
2021 ◽  
Vol 21 (18) ◽  
pp. 6295
Author(s):  
Xianfan Wang ◽  
Jianhua Yang ◽  
Meng Chen ◽  
Lijun Miao ◽  
Tengchao Huang

Primary angular vibration calibration devices based on laser interferometers play a crucial role in evaluating the dynamic performance of inertial sensing devices. Here, we propose a sinusoidal phase-modulated angle interferometer (SPMAI) to realize angular vibration measurements over a frequency range of 1–1000 Hz, in which the sinusoidal measurement retro-reflector (SMR) and the phase generation carrier (PGC) demodulation algorithm are adopted to track the dynamic angle variation. A comprehensive theoretical analysis is presented to reveal the relationship between demodulation performance of the SPMAI and several factors, such as phase modulation depth, carrier phase delay and sampling frequency. Both the simulated and experimental results demonstrate that the proposed SPMAI can achieve an angular vibration measurement with amplitude of sub-arcsecond under given parameters. Using the proposed SPMAI, the frequency bandwidth of an interferometric fiber-optic gyroscope (IFOG) is successfully determined to be 848 Hz.

2021 ◽  
Vol 64 (4) ◽  
pp. 1247-1258
Author(s):  
Yang Li ◽  
Lizhang Xu ◽  
Zhipeng Gao ◽  
En Lu ◽  
Yaoming Li

HighlightsThe relationship of vibration and header loss was studied by multi-point vibration measurement and loss collection test.There was an approximately linear positive correlation between total header vibration and total rapeseed header loss.The header frame was analyzed and optimized through modal simulation and testing.The total rapeseed header loss of the improved header was reduced by 33.2% to 46.9%.Abstract. In view of the current large rapeseed header losses of rape combine harvesters, the effects of the header on rapeseed header loss were studied from the perspective of vibration. First, the vibrations at various measuring points on the header during rape harvest were studied using a data acquisition and analysis system while performing collection tests of rapeseed header loss with the sample slot method. The relationships between total header vibration and total rapeseed header loss and between vertical cutter vibration and rapeseed vertical cutter loss were shown to have a positive correlation, and they all increased with the increase in engine speed. Vertical cutter loss accounted for 31.2% to 42.4% of the total rapeseed header loss. Modal analysis and optimization of the header frame were then performed by simulation and test. The natural frequencies of the first-order and second-order modes of the optimized header were increased, and the possibility of resonance with other working parts was eliminated. Finally, the improved header was tested during rape harvest. The results showed that the total vibration of the improved header was reduced by 19.9% to 43.9%, and the total rapeseed header loss was reduced by 33.2% to 46.9%. The vertical cutter vibration was reduced by 30.5% to 49.8%, and the rapeseed vertical cutter loss was reduced by 20.8% to 34.7%. In addition, the vibration and rapeseed loss of the improved header had relatively slow rates of increase with the increase in engine speed. The method of reducing rapeseed loss by reducing the header vibration achieved an obvious and positive effect. Keywords: Frame optimization, Modal analysis, Rape combine harvester, Rapeseed header loss, Vibration.


Author(s):  
Hailong Cui ◽  
Yang Wang ◽  
Xiaobin Yue ◽  
Yifei Li ◽  
Zhengyi Jiang

This study utilizes a dynamic mesh technology to investigate the dynamic performance of aerostatic thrust bearings with orifice restrictor, multiple restrictors, and porous restrictor. An experiment, which investigates the bearing static load capacity, was carried out to verify the calculation accuracy of dynamic mesh technology. Further, the impact of incentive amplitude, incentive frequency, axial eccentricity ratio, and non-flatness on the bearing dynamic performance was also studied. The results show incentive amplitude effect can be ignored at the condition of amplitude less than 5% film thickness, while the relationship between dynamic characteristics and incentive frequency presented a strong nonlinear relationship in the whole frequency range. The change law of dynamic stiffness and damping coefficient for porous restrictor was quite different from orifice restrictor and multiple restrictors. The bearing dynamic performance increased significantly with the growth of axial eccentricity ratio, and the surface non-flatness enhanced dynamic performance of aerostatic thrust bearings.


2011 ◽  
Vol 38 (12) ◽  
pp. 1208003
Author(s):  
夏巍 Xia Wei ◽  
郝辉 Hao Hui ◽  
王峰 Wang Feng ◽  
王鸣 Wang Ming ◽  
郭冬梅 Guo Dongmei ◽  
...  

2013 ◽  
Author(s):  
Spozmai Panezai ◽  
Dayong Wang ◽  
Jie Zhao ◽  
Yunxin Wang ◽  
Sijin Ma ◽  
...  

2012 ◽  
Vol 157-158 ◽  
pp. 245-249 ◽  
Author(s):  
Xu You Li ◽  
Na Zhang

The sway motion of ships follows sine law. Therefore, it needs high dynamic performance of fiber optic gyroscope (FOG) to meet the serious working environment. A new test method was introduced to make reasonable assessment on the dynamic performance of FOG. The principle of this new test method was that the sine wave provided by the IP core in FPGA was superimposed on the digital ladder to simulate the input signal of sway motion. It could be proved that the serial of sine signal, which was generated by this method, was equivalent to the external input signal. Moreover, the dynamic error model of FOG was established to provide the theory of dynamic test. The results of dynamic test of FOG indicated that the dynamic error did not have divergent trends, the system parameters set was reasonable and the FOG system was stable. It also can be seen that dynamic error of FOG was increased with the increasing of sine wave amplitude, which was accord with the actual situation. The new dynamic test method of FOG was verified.


Sports ◽  
2020 ◽  
Vol 8 (5) ◽  
pp. 63 ◽  
Author(s):  
Danny Lum ◽  
G. Gregory Haff ◽  
Tiago M. Barbosa

The purpose of this article was to review the data on the relationship between multi-joint isometric strength test (IsoTest) force-time characteristics (peak force, rate of force development and impulse) and dynamic performance that is available in the current literature. Four electronic databases were searched using search terms related to IsoTest. Studies were considered eligible if they were original research studies that investigated the relationships between multi-joint IsoTest and performance of dynamic movements; published in peer-reviewed journals; had participants who were athletes or active individuals who participate in recreational sports or resistance training, with no restriction on sex; and had full text available. A total of 47 studies were selected. These studies showed significant small to large correlations between isometric bench press (IBP) force-time variables and upper body dynamic performances (r2 = 0.221 to 0.608, p < 0.05) and significant small to very large correlation between isometric squat (ISqT) (r2 = 0.085 to 0.746, p < 0.05) and isometric mid-thigh pull (IMTP) (r2 = 0.120 to 0.941, p < 0.05) force-time variables with lower body dynamic performances. IsoTest force-time characteristics were shown to have small to very large correlations with dynamic performances of the upper and lower limbs as well as performance of sporting movements (r2 = 0.118 to 0.700, p < 0.05). These data suggest that IsoTest force-time characteristics provide insights into the force production capability of athletes which give insight into dynamic performance capabilities.


2010 ◽  
Vol 426-427 ◽  
pp. 106-108 ◽  
Author(s):  
De Gong Chang ◽  
Zhi Juan Xiao ◽  
Y.H. Liu ◽  
H. Li

Based on the analyses of the yarn tension and the mathematical model of the magnetic powder brake, the digital simulation of the yarn tension fuzzy control system was performed by using MATLAB Simulink. The relationship between the structure parameters and the system dynamic performance was then obtained, and the system scheme was justified.


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