Study on Practical FBG Acceleration System

2011 ◽  
Vol 346 ◽  
pp. 546-550
Author(s):  
Wei Guang Zhang ◽  
Jian Zhang
Keyword(s):  
System Application ◽  
High Frequency ◽  
High Sensitivity ◽  
Acceleration Measurement ◽  
Cross Sensitivity ◽  
Loop Control ◽  
Sensitivity Problem ◽  
Micro Vibration ◽  
Low Sensitivity ◽  
Close Loop Control

A micro vibration, high sensitivity FBG demodulation system with close loop control is presented. By introducing a close loop control, the difficulty in matched FBG making process is overcame. Further more, the FBG strain-temperature cross sensitivity problem is settled. And low sensitivity in high frequency of cantilever FBG accelerator is overcame either. An example of the system application in acceleration measurement is introduced.

Fingertip Force/Torque Sensor With High Isotropy and Sensitivity for Underwater Manipulation

2010 ◽  
Author(s):  
Qiaokang Liang ◽  
Dan Zhang ◽  
Zhongzhe Chi ◽  
Yunjian Ge
Keyword(s):  
Robot Manipulators ◽  
Control Strategies ◽  
High Sensitivity ◽  
Force Sensor ◽  
Interaction Force ◽  
Underwater Robot ◽  
Loop Control ◽  
Fingertip Force ◽  
Underwater Manipulation ◽  
Close Loop Control

Control strategies for robotic manipulators in underwater applications are still immature compared with the strategies of the manipulators on land. Part of the reason is that there is no precise force/torque information, which is essential to the close-loop control. Unlike the sensor applied on the ground, the sensors for underwater applications have to endure the high-pressure, low-temperature and corrosive environment. Therefore, aimed at obtaining the accurate interaction force/torque between underwater robot manipulators and objects, a novel four-dimensional fingertip force sensor is presented based on e-type membrane for underwater robot manipulators. A seal technique is described. Experimental results demonstrate the design could detect force/torque with good linearity, high sensitivity and weak couplings.

scholarly journals System integration and control design of a maglev platform for space vibration isolation

2019 ◽  
Vol 25 (11) ◽  
pp. 1720-1736 ◽  
Author(s):  
Zhaopei Gong ◽  
Liang Ding ◽  
Honghao Yue ◽  
Haibo Gao ◽  
Rongqiang Liu ◽  
...  
Keyword(s):  
System Integration ◽  
Degrees Of Freedom ◽  
Vibration Isolation ◽  
Minimum Energy ◽  
Optimization Method ◽  
Dominant Factor ◽  
Loop Control ◽  
Scientific Experiments ◽  
Micro Vibration ◽  
Close Loop Control

Micro-vibration has been a dominant factor impairing the performance of scientific experiments which are expected to be deployed in a micro-gravity environment such as a space laboratory. The micro-vibration has serious impact on the scientific experiments requiring a quasi-static environment. Therefore, we proposed a maglev vibration isolation platform operating in six degrees of freedom (DOF) to fulfill the environmental requirements. In view of the noncontact and large stroke requirement for micro-vibration isolation, an optimization method was utilized to design the actuator. Mathematical models of the actuator's remarkable nonlinearity were established, so that its output can be compensated according to a floater's varying position and a system's performance may be satisfied. Furthermore, aiming to adapt to an energy-limited environment such as space laboratory, an optimum allocation scheme was put forward, considering that the actuator's nonlinearity, accuracy, and minimum energy-consumption can be obtained simultaneously. In view of operating in 6-DOF, methods for nonlinear compensation and system decoupling were discussed, and the necessary controller was also presented. Simulation and experiments validate the system's performance. With a movement range of 10 × 10 × 8 mm and rotations of 200 mrad, the decay ratio of −40 dB/Dec between 1 and 10 Hz was obtained under close-loop control.

scholarly journals In-flight calibration of the Hot Ion Analyser on board Cluster

2014 ◽  
Vol 3 (1) ◽  
pp. 49-58 ◽  
Author(s):  
A. Blagau ◽  
I. Dandouras ◽  
A. Barthe ◽  
S. Brunato ◽  
G. Facskó ◽  
...  
Keyword(s):  
High Frequency ◽  
Detection Efficiency ◽  
Radiation Detector ◽  
Three Dimensional ◽  
High Sensitivity ◽  
Relaxation Experiment ◽  
Cluster Ion ◽  
Low Sensitivity ◽  
Changes Over Time ◽  
Over Time

Abstract. The Hot Ion Analyser (HIA), part of the Cluster Ion Spectrometry experiment, has the objective to measure the three-dimensional velocity distributions of ions. Due to a variety of factors (exposure to radiation, detector fatigue and aging, changes in the operating parameters, etc.), the particles' detection efficiency changes over time, prompting for continuous in-flight calibration. This is achieved by comparing the HIA data with the data provided by the WHISPER (Waves of HIgh frequency and Sounder for Probing of Electron density by Relaxation) experiment on magnetosheath intervals, for the high-sensitivity section of the instrument, or solar wind intervals, for the low-sensitivity section. The paper presents in detail the in-flight calibration methodology, reports on the work carried out for calibrating HIA and discusses plans to extend this activity in order to ensure the instrument's highest data accuracy.

The Research of "Constant Current First, Constant Voltage After" Close-Loop Control Charging Tactics of High Frequency Charger

2014 ◽  
Vol 494-495 ◽  
pp. 1556-1560
Author(s):  
Xian Hui Zhang
Keyword(s):  
Electric Vehicle ◽  
High Frequency ◽  
Structure Design ◽  
Theoretical Research ◽  
Constant Current ◽  
Research Subject ◽  
Constant Voltage ◽  
Practical Application ◽  
Loop Control ◽  
Close Loop Control

This article takes non-on-board high frequency charger of pure electric vehicle for research subject, based on the overall structure design, aimed at the deficiency of constant current and constant voltage charging, put forward constant current first, constant voltage afterclose-loop control charging tactics, and analyses charging principle and process in deep, has a certain amount of theoretical research and practical application value.

An Efficient Approach for Modeling and Control of a Quadrotor

2016 ◽  
Vol 4 (2) ◽  
pp. 1-16
Author(s):  
Ahmed S. Khusheef
Keyword(s):  
Pid Control ◽  
Control Method ◽  
Mechanical Design ◽  
Loop Control ◽  
Modeling And Control ◽  
Loop Control System ◽  
And Control ◽  
Close Loop Control ◽  
Close Loop Control System ◽  
Made In

 A quadrotor is a four-rotor aircraft capable of vertical take-off and landing, hovering, forward flight, and having great maneuverability. Its platform can be made in a small size make it convenient for indoor applications as well as for outdoor uses. In model there are four input forces that are essentially the thrust provided by each propeller attached to each motor with a fixed angle. The quadrotor is basically considered an unstable system because of the aerodynamic effects; consequently, a close-loop control system is required to achieve stability and autonomy. Such system must enable the quadrotor to reach the desired attitude as fast as possible without any steady state error. In this paper, an optimal controller is designed based on a Proportional Integral Derivative (PID) control method to obtain stability in flying the quadrotor. The dynamic model of this vehicle will be also explained by using Euler-Newton method. The mechanical design was performed along with the design of the controlling algorithm. Matlab Simulink was used to test and analyze the performance of the proposed control strategy. The experimental results on the quadrotor demonstrated the effectiveness of the methodology used.

scholarly journals High-frequency rectifiers based on type-II Dirac fermions

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Libo Zhang ◽  
Zhiqingzi Chen ◽  
Kaixuan Zhang ◽  
Lin Wang ◽  
Huang Xu ◽  
...  
Keyword(s):  
High Frequency ◽  
Dynamic Range ◽  
High Sensitivity ◽  
High Dynamic Range ◽  
Anisotropy Ratio ◽  
Dirac Fermions ◽  
Topological States ◽  
Topological Semimetals ◽  
Polarized Surface ◽  
Symmetry Protected

AbstractThe advent of topological semimetals enables the exploitation of symmetry-protected topological phenomena and quantized transport. Here, we present homogeneous rectifiers, converting high-frequency electromagnetic energy into direct current, based on low-energy Dirac fermions of topological semimetal-NiTe2, with state-of-the-art efficiency already in the first implementation. Explicitly, these devices display room-temperature photosensitivity as high as 251 mA W−1 at 0.3 THz in an unbiased mode, with a photocurrent anisotropy ratio of 22, originating from the interplay between the spin-polarized surface and bulk states. Device performances in terms of broadband operation, high dynamic range, as well as their high sensitivity, validate the immense potential and unique advantages associated to the control of nonequilibrium gapless topological states via built-in electric field, electromagnetic polarization and symmetry breaking in topological semimetals. These findings pave the way for the exploitation of topological phase of matter for high-frequency operations in polarization-sensitive sensing, communications and imaging.

scholarly journals Second harmonic generation correlation spectroscopy for characterizing translationally diffusing protein nanocrystals

2016 ◽  
Vol 72 (7) ◽  
pp. 849-859
Author(s):  
Ximeng Y. Dow ◽  
Christopher M. Dettmar ◽  
Emma L. DeWalt ◽  
Justin A. Newman ◽  
Alexander R. Dow ◽  
...  
Keyword(s):  
Second Harmonic Generation ◽  
Harmonic Generation ◽  
Unit Volume ◽  
Second Harmonic ◽  
Incident Beam ◽  
High Sensitivity ◽  
Correlation Spectroscopy ◽  
Optical Process ◽  
Active Nanoparticles ◽  
Low Sensitivity

Second harmonic generation correlation spectroscopy (SHG-CS) is demonstrated as a new approach to protein nanocrystal characterization. A novel line-scanning approach was performed to enable autocorrelation analysis without sample damage from the intense incident beam. An analytical model for autocorrelation was developed, which includes a correction for the optical scattering forces arising when focusing intense, infrared beams. SHG-CS was applied to the analysis of BaTiO3nanoparticles ranging from 200 to ∼500 nm and of photosystem I nanocrystals. A size distribution was recovered for each sample and compared with the size histogram measured by scanning electron microscopy (SEM). Good agreement was observed between the two independent measurements. The intrinsic selectivity of the second-order nonlinear optical process provides SHG-CS with the ability to distinguish well ordered nanocrystals from conglomerates and amorphous aggregates. Combining the recovered distribution of particle diameters with the histogram of measured SHG intensities provides the inherent hyperpolarizability per unit volume of the SHG-active nanoparticles. Simulations suggest that the SHG activity per unit volume is likely to exhibit relatively low sensitivity to the subtle distortions within the lattice that contribute to resolution loss in X-ray diffraction, but high sensitivity to the presence of multi-domain crystals.

Acoustic radiation simulation and pre-stress effect on compact acoustic levitation platform

2019 ◽  
Vol 33 (07) ◽  
pp. 1950080 ◽  
Author(s):  
Bin Wei ◽  
Yongyong He ◽  
Wei Wang
Keyword(s):  
Pressure Distribution ◽  
Acoustic Radiation ◽  
Near Field ◽  
Parameters Optimization ◽  
Squeeze Film ◽  
Acoustic Levitation ◽  
Stress Effect ◽  
Biological Engineering ◽  
Loop Control ◽  
Close Loop Control

In order to satisfy the requirements of precise components with tidiness, low power and high stability in the field of biological engineering, medical equipment and semiconductors etc. a pre-stress acoustic transport prototype without horn was proposed in this paper. The mechanism of levitation and transport which is driven by orthogonal waves was revealed by the analysis of waveform and squeeze film characteristics in high-frequency exciting condition; also, the electric, solid and acoustic coupled finite element method (FEM) was established to investigate the effect of pre-stress and acoustic pressure distribution in the near field. The levitation and driving capacity of near field acoustic levitation (NFAL) transport platform without horns can be proved in this experiment and further to achieve the goal of parameters optimization. The theoretical and experimental results indicate that the pre-stress has a significant effect on resonant frequency and levitating stability, the pre-stress are determined by the DC voltage offset which is related to the system working point so that we cannot increase the offset and exciting voltage unlimitedly to improve the stability. At the same time, the calculated pressure distribution of acoustic radiation can generally reflect the regional bearing capacity in near and far field for levitation. These achievements can partly solve the problem of accuracy design of prototype and thickness of gas film, supporting for accuracy close loop control of levitating height.

The Design and Simulation of Three-Phase PWM Converter

2013 ◽  
Vol 321-324 ◽  
pp. 917-920
Author(s):  
Guang Ya Liu ◽  
Xiao Song Li
Keyword(s):  
High Frequency ◽  
Closed Loop ◽  
Voltage Source ◽  
Pwm Rectifier ◽  
Phase Voltage ◽  
Pwm Converter ◽  
Loop Control ◽  
Closed Loop Control System ◽  
Three Phase ◽  
Loop Control System

Three-phase voltage source PWM rectifier generally adopts double closed loop control system. According to the high frequency characteristic of three-phase voltage source PWM rectifier, this paper put forward the setting method of current inner ring regulator and voltage outer ring regulator PI parameter. Finally, it is verified by simulation.

Influence of Irrational Beliefs and Sensitivity to a Person on Future Psychology Students’ Propensity to Coercion or Nonviolence

2021 ◽  
pp. 143-165
Author(s):  
V.G. Maralov ◽  
◽  
V.A. Sitarov ◽  
Keyword(s):  
Irrational Beliefs ◽  
High Sensitivity ◽  
Daily Practice ◽  
Psychology Students ◽  
State Universities ◽  
Low Level ◽  
Level Of Understanding ◽  
Low Sensitivity ◽  
High Level ◽  
Dependent Type

The relevance of the problem is due to the importance of identifying factors that determine the propensity of students to coercion or nonviolence, creating psychological and pedagogical conditions for the formation of the socionomic sphere of nonviolent competencies for future specialists at universities. The theoretical basis of the study was the position of nonviolence as a daily practice of interaction, by which we understand the ability of a person to choose from a number of possible alternatives that carry the least charge of coercion. The aim of the work was to study the influence of irrational beliefs and sensitivity to a person (interest, empathy, understanding and assistance) on the students’ tendency to coercion, manipulation, non-violence and non-interference in the processes of interaction with people. The hypothesis was tested that the tendency of students to coercion, manipulation, and noninterference will be due to expressed irrational beliefs and low level of sensitivity to a person and the tendency to non-violence will be explained by the absence of irrational beliefs and a high level of sensitivity to a person. The study involved 125 students of pedagogical and psychological faculties of the Moscow Humanitarian and Cherepovets State universities. The authors used questionnaires to identify the positions of interaction among students and sensitivity to a person, as well as a list of irrational beliefs proposed by A. Beck and A. Freeman. It is established that the tendency to both coercion and manipulation are determined by the beliefs of anti-social type and low sensitivity to the person. The tendency to manipulate the narcissistic beliefs, high interest in people and understanding them, at the same time the tendency to non-violence and non-interference are determined by beliefs of avoidant and dependent types with a low level of understanding people. And a tendency to non-interference is determined by beliefs of dependent type with unexpressed orientation on helping. The tendency to nonviolence is determined by the high sensitivity to a person and the absence of irrational beliefs of antisocial, passive-aggressive and narcissistic types. As a result, the conclusion is made about the need to form purposefully the ability to nonviolent interaction among students, which should include the work on awareness and overcoming irrational beliefs and the development of sensitivity to a person. The obtained results can be used in practical work with students on the formation of their nonviolent competencies.

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