scholarly journals Damping Asymmetry Trimming Based on the Resistance Heat Dissipation for Coriolis Vibratory Gyroscope in Whole-Angle Mode

Micromachines ◽  
2020 ◽  
Vol 11 (10) ◽  
pp. 945
Author(s):  
Kechen Guo ◽  
Yulie Wu ◽  
Yongmeng Zhang ◽  
Jiangkun Sun ◽  
Dingbang Xiao ◽  
...  
Keyword(s):  
Parallel Plate ◽  
Heat Dissipation ◽  
Scale Factor ◽  
Control Force ◽  
Rate Measurement ◽  
Symmetrical Structure ◽  
Tuning Method ◽  
Vibratory Gyroscope ◽  
Hemispherical Resonator ◽  
The One

Damping asymmetry is one of the most important factors that determines the performance of Coriolis Vibratory Gyroscope. In this paper, a novel damping tuning method for the resonator with parallel plate capacitors is presented. This damping tuning method is based on resistance heat dissipation and the tuning effect is characterized by the control force in Whole-Angle mode. As the damping tuning and stiffness tuning in the resonator with parallel plate capacitors are coupled with each other, a corresponding tuning system is designed. To verify the tuning effects, experiments are conducted on a hemispherical resonator gyroscope with Whole-Angle mode. The damping tuning theories is demonstrated by the testing results and 87% of the damping asymmetry is reduced by this tuning method with a cost of 3% decaying time. Furthermore, the angle-dependent drift in rate measurement after tuning is only 15.6% of the one without tuning and the scale factor nonlinearity decreases from 5.49 ppm to 2.66 ppm. The method can be further applied on the damping tuning in other resonators with symmetrical structure.

scholarly journals Effect of Uneven Electrostatic Forces on the Dynamic Characteristics of Capacitive Hemispherical Resonator Gyroscopes

Sensors ◽  
2019 ◽  
Vol 19 (6) ◽  
pp. 1291 ◽  
Author(s):  
Zeyuan Xu ◽  
Guoxing Yi ◽  
Meng Er ◽  
Chao Huang
Keyword(s):  
Scale Factor ◽  
Harmonic Amplitude ◽  
Electrostatic Forces ◽  
Zero Bias ◽  
Output Error ◽  
Vibratory Gyroscope ◽  
Influence Mechanism ◽  
Hemispherical Resonator ◽  
Order Of Magnitude ◽  
Modification Rate

The hemispherical resonator gyroscope (HRG) is a typical capacitive Coriolis vibratory gyroscope whose performance is inevitably influenced by the uneven electrostatic forces caused by the uneven excitation capacitance gap between the resonator and outer base. First, the mechanism of uneven electrostatic forces due to the significantly uneven capacitance gap in that the non-uniformity of the electrostatic forces can cause irregular deformation of the resonator and further affect the performance and precision of the HRG, was analyzed. According to the analyzed influence mechanism, the dynamic output error model of the HRG was established. In this work, the effect of the first four harmonics of the uneven capacitance gap on the HRG was investigated. It turns out that the zero bias and output error, caused by the first harmonic that dominates mainly the amplitude of the uneven capacitance gap, increase approximately linearly with the increase of the amplitude, and periodically vary with the increase of the phase. The effect of the other three harmonics follows the same law, but their amplitudes are one order of magnitude smaller than that of the first one, thus their effects on the HRG can be neglected. The effect of uneven electrostatic forces caused by the first harmonic on the scale factor is that its nonlinearity increases approximately linearly with the increase of the harmonic amplitude, which was analyzed in depth. Considering comprehensively the zero bias, the modification rate of output error, and scale factor nonlinearity, the tolerance towards the uneven excitation capacitance gap was obtained.

scholarly journals On the optimal control force applied to tuned mass dampers for multi-degree-of-freedom systems

2004 ◽  
Vol 26 (1) ◽  
pp. 1-10
Author(s):  
Nguyen Dong Anh ◽  
Nguyen Chi Sang
Keyword(s):  
Optimal Control ◽  
Numerical Study ◽  
Degree Of Freedom ◽  
Control Force ◽  
Linear Quadratic ◽  
Tuned Mass Dampers ◽  
Coloured Noise ◽  
Optimal Theory ◽  
The One ◽  
Better Than

The design of active TMD for multi-degree-of-freedom systems subjected to second order coloured noise excitation is considered using the linear quadratic optimal theory. A detailed numerical study is carried out for a 2-DOF system. It is shown that the effectiveness of active TMD is better than the one of passive TMD.

scholarly journals Heuristic derivation of Casimir effect in minimal length theories

2020 ◽  
Vol 29 (02) ◽  
pp. 2050011 ◽  
Author(s):  
Massimo Blasone ◽  
Gaetano Lambiase ◽  
Giuseppe Gaetano Luciano ◽  
Luciano Petruzziello ◽  
Fabio Scardigli
Keyword(s):  
Field Theory ◽  
Parallel Plate ◽  
Casimir Effect ◽  
Generalized Uncertainty Principle ◽  
Casimir Energy ◽  
Minimal Length ◽  
Quadratic Term ◽  
Quantum Field ◽  
The One ◽  
Plate Geometry

We propose a heuristic derivation of Casimir effect in the context of minimal length theories based on a Generalized Uncertainty Principle (GUP). By considering a GUP with only a quadratic term in the momentum, we compute corrections to the standard formula of Casimir energy for the parallel-plate geometry, the sphere and the cylindrical shell. For the first configuration, we show that our result is consistent with the one obtained via more rigorous calculations in Quantum Field Theory (QFT). Experimental developments are finally discussed.

Fundamental Concepts and an Innovating Approach for Extended Surface Heat Transfer

2005 ◽  
Author(s):  
Panagiotis Razelos
Keyword(s):  
Heat Transfer ◽  
Heat Dissipation ◽  
Vital Role ◽  
Surface Heat ◽  
Surface Heat Transfer ◽  
Novel Approach ◽  
Mathematical Expressions ◽  
Extended Surface ◽  
Simplifying Assumptions ◽  
The One

In this work we re-examine the main fin equation qf = ηfAfΔT, proposed by Gardner [1] that has been used for the last sixty years to determine the performance of fins. The fundamental concepts of extended surface heat transfer are introduced, and their mathematical expressions are derived. The vital role of fin effectiveness, a term also introduced by Gardner [1] is established. It is shown that the effectiveness is inextricably linked in proving the validity of the simplifying assumptions that most of the fins’ endeavors are based on. It is also shown that the common practice of using the efficiency to predict the fin’s performance leads to serious errors. A novel approach to fin analysis, based on a proposed transformation of coordinates, is presented, which can be employed to considerably simplify the pertinent differential equations and obtain more friendly expressions describing the fin’s performance. The heat dissipation is expressed in a non-dimensional form and for several practical cases polynomial expressions have developed, that will help students to engage in rudimentary fin designs. It is also shown that, the one-dimensional approach can be used to obtain solutions involving extended surfaces made from anisotropic material. Three examples serve to illustrate the usefulness of our method.

Analysis of compensation for a g-sensitivity scale-factor error for a MEMS vibratory gyroscope

2015 ◽  
Vol 25 (11) ◽  
pp. 115006 ◽  
Author(s):  
Byung Su Park ◽  
KyungJun Han ◽  
SangWoo Lee ◽  
MyeongJong Yu
Keyword(s):  
Scale Factor ◽  
Vibratory Gyroscope

scholarly journals Benevolence Toward Schizophrenia Scale: Construction and evidence of validation

2019 ◽  
Vol 36 ◽  
Author(s):  
Juliana Rízia Félix de MELO ◽  
Silvana Carneiro MACIEL ◽  
Marcelo Xavier de OLIVEIRA ◽  
Leoncio Francisco CAMINO ◽  
Thayro Andrade CARVALHO
Keyword(s):  
Factor Analysis ◽  
University Students ◽  
Exploratory Factor Analysis ◽  
Factor Structure ◽  
Goodness Of Fit ◽  
Scale Factor ◽  
Scale Construction ◽  
Cronbach's Alpha ◽  
The One ◽  
Composite Reliability

Abstract The aim of this study was to construct and seek evidence for the validity of the Escala de Benevolência frente à Esquizofrenia (Benevolence Toward Schizophrenia Scale). Two studies were conducted in Joao Pessoa, Paraíba, Brazil. Study 1 describes the development and evidence of the factor validity of the Benevolence Toward Schizophrenia Scale with a sample composed of 200 university students aged 16 to 51 years old (M = 25.31; SD = 7.21). The data were subjected to exploratory factor analysis, which revealed one single seven-item factor that explained 37.74% of the variance and a satisfactory Cronbach’s alpha (0.77). The aim of Study 2 was to test the goodness-of-fit of the Benevolence Toward Schizophrenia Scale factor structure with a sample composed of 200 university students aged 16 to 52 years old (M = 24.82; SD = 6.97). The one-factor structure exhibited adequate goodness-of-fit; the composite reliability value was 0.83, which indicates scale stability and satisfactory psychometric parameters for assessing benevolent prejudice toward schizophrenia.

scholarly journals Plug-and-Play Few-shot Object Detection with Meta Strategy and Explicit Localization Inference

2021 ◽  
Author(s):  
Junying Huang ◽  
Fan Chen ◽  
Liang Lin ◽  
dongyu zhang
Keyword(s):  
Object Detection ◽  
Fine Tuning ◽  
The Novel ◽  
Plug And Play ◽  
Tuning Method ◽  
One Step ◽  
Tuning Process ◽  
General Object ◽  
The One ◽  
Parallel Techniques

Aiming at recognizing and localizing the object of novel categories by a few reference samples, few-shot object detection is a quite challenging task. Previous works often depend on the fine-tuning process to transfer their model to the novel category and rarely consider the defect of fine-tuning, resulting in many drawbacks. For example, these methods are far from satisfying in the low-shot or episode-based scenarios since the fine-tuning process in object detection requires much time and high-shot support data. To this end, this paper proposes a plug-and-play few-shot object detection (PnP-FSOD) framework that can accurately and directly detect the objects of novel categories without the fine-tuning process. To accomplish the objective, the PnP-FSOD framework contains two parallel techniques to address the core challenges in the few-shot learning, i.e., across-category task and few-annotation support. Concretely, we first propose two simple but effective meta strategies for the box classifier and RPN module to enable the across-category object detection without fine-tuning. Then, we introduce two explicit inferences into the localization process to reduce its dependence on the annotated data, including explicit localization score and semi-explicit box regression. In addition to the PnP-FSOD framework, we propose a novel one-step tuning method that can avoid the defects in fine-tuning. It is noteworthy that the proposed techniques and tuning method are based on the general object detector without other prior methods, so they are easily compatible with the existing FSOD methods. Extensive experiments show that the PnP-FSOD framework has achieved the state-of-the-art few-shot object detection performance without any tuning method. After applying the one-step tuning method, it further shows a significant lead in both efficiency, precision, and recall, under varied few-shot evaluation protocols.

scholarly journals The Most Probable Cosmic Scale Factor Consistent with the Cosmological Principle, General Relativity and the SMPP

2021 ◽  
Author(s):  
Arthur N. James
Keyword(s):  
General Relativity ◽  
Particle Physics ◽  
Probability Distributions ◽  
Scale Factor ◽  
Dark Sector ◽  
New Model ◽  
Cosmological Principle ◽  
Cosmic Scale ◽  
Einstein's Equation ◽  
The One

Current literature on the evolution of the cosmic scale factor is dominated by models using a dark sector, these all involve making many conjectures beyond the basic assumption that the Cosmological Principle selects a space–time metric of the Friedmann–Lemaître–Robertson–Walker type through which ordinary Standard Model of Particle Physics matter moves according to General Relativity. In this chapter a different model is made using the same basic assumptions but without making extra conjectures, it depends on following the idea introduced by Boltzmann that when physically meaningful concepts fluctuate the value which will be observed is the one which has the highest probability. This change removes the mathematically incorrect procedure of averaging the matter density before solving Einstein’s Equation, the procedure which causes the introduction of many of the conjectures. In the non-uniform era the changes are that the evolution of the scale factor is influenced by the formation of structure and removes the conjecture of having to use two inconsistent probability distributions for matter through space, one to calculate the scale factor and one to represent structure. The new model is consistent from the earliest times through to the present epoch. This new model is open and matches SNe 1a redshift data, an observation which makes it a viable candidate and implies that it should be fully investigated.

Framed Harvesters for Collecting Energy From Vibrations in Industrial Plants

2019 ◽  
Author(s):  
Alberto Doria
Keyword(s):  
Sensitivity Analysis ◽  
Experimental Tests ◽  
Industrial Plants ◽  
Tuning Method ◽  
The One ◽  
Piezoelectric Harvester

Abstract The idea of increasing the number of resonance conditions of a cantilever piezoelectric harvester by coupling the harvester with a frame that surrounds the harvester’s body is presented and discussed. Experimental tests on prototypes show that it is possible to design framed harvesters able to generate significant powers at two frequencies. Since the framed harvesters will be used for harvesting energy from periodic vibrations characterized by multiple harmonics, a tuning method is needed. For this reason a numerical sensitivity analysis is performed to analyze the effect on harvester tuning of small masses mounted on the frame. A prototype tuned to 40 and 80 Hz is developed and tested, its performance is compared with the one of a system of two simple harvesters tuned to the same frequencies.

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