Improvement and Realization of Miniature Flexible Gyro in the Photoelectric Platform

2013 ◽  
Vol 655-657 ◽  
pp. 697-700
Author(s):  
Ping Wang ◽  
Jing Yang ◽  
Jun Jun Yao
Keyword(s):  
Engineering Design ◽  
Angular Position ◽  
Nutation Frequency ◽  
Output Noise ◽  
Frequency Components ◽  
Two Measures ◽  
Output Characteristics ◽  
Stabilized Platform ◽  
Gyroscopic Motion

Generally ,it was precession of flexible gyroscopic not gyroscopic nutation which was just considered in engineering design. However, in photoelectric stabilized platform, this nutation characteristics of angular position flexible gyro has been restricting the stabilized accuracy of platform seriously. In this paper, firstly the output characteristics of a miniature flexible gyro was measured by characteristic of gyroscopic motion, four main kinds of frequency components in output characteristics was analysed. The methods were realized in the miniature flexible gyroscope in the laboratory by adopting the two measures of the secondary trap circuit and improvement of torque component.Test results showed that, the improvements made nutation frequency of gyro and envelope at 40Hz converged fastly , and the output noise of gyro angular position was decayed to more than15dB. In the end, the gyro was applied to chariot photoelectric stabilized platform ,the isolation of platform and carrier got improved from 1~2mil to 0.3mil.

scholarly journals Scalable Output Linear Actuators, a Novel Design Concept Using Shape Memory Alloy Wires Driven by Fluid Temperature

Machines ◽  
2021 ◽  
Vol 9 (1) ◽  
pp. 14
Author(s):  
Andres Osorio Salazar ◽  
Yusuke Sugahara ◽  
Daisuke Matsuura ◽  
Yukio Takeda
Keyword(s):  
Shape Memory Alloy ◽  
Shape Memory ◽  
Angular Position ◽  
Scale Factor ◽  
Design Concept ◽  
Fluid Temperature ◽  
Step Size ◽  
Simple Method ◽  
Output Characteristics ◽  
Novel Design

In this paper, the concept of scalability for actuators is introduced and explored, which is the capability to freely change the output characteristics on demand: displacement and force for a linear actuator, angular position and torque for a rotational actuator. This change can either be used to obtain power improvement (with a constant scale factor), or to improve the usability of a robotic system according to variable conditions (with a variable scale factor). Some advantages of a scalable design include the ability to adapt to changing environments, variable resolution of step size, ability to produce designs that are adequate for restricted spaces or that require strict energy efficiency, and intrinsically safe systems. Current approaches for scalability in actuators have shortcomings: the method to achieve scalability is complex, so obtaining a variable scaling factor is challenging, or they cannot scale both output characteristics simultaneously. Shape Memory Alloy (SMA) wire-based actuators can overcome these limitations, because its two output characteristics, displacement and force, are physically independent from each other. In this paper we present a novel design concept for linear scalable actuators that overcome SMA design and scalability limitations by using a variable number of SMA wires mechanically in parallel, immersed in a liquid that transmits heat from a separate heat source (wet activation). In this concept, more wires increase the maximum attainable force, and longer wires increase the maximum displacement. Prototypes with different number of SMA wires were constructed and tested in isometric experiments to determine force vs. temperature behavior and time response. The heat-transmitting liquid was either static or flowing using pumps. Scalability was achieved with a simple method in all tested prototypes with a linear correlation of maximum force to number of SMA wires. Flowing heat transmission achieved higher actuation bandwidth.

Development of a Parallel-Series Stabilized Platform System

2013 ◽  
Vol 319 ◽  
pp. 414-418
Author(s):  
Li Ling Wang ◽  
Jin Zhuang Xiao ◽  
Hong Rui Wang ◽  
Xiu Ling Liu ◽  
Zheng Gao
Keyword(s):  
Angular Position ◽  
Current Loop ◽  
Closed Loops ◽  
Data Acquisition Card ◽  
Spherical Parallel Mechanism ◽  
In Series ◽  
Software And Hardware ◽  
Stabilized Platform ◽  
Platform System ◽  
Wide Speed Range

This document designed a stabilized platform of 2-DOF spherical parallel mechanism with 1-DOF in series. DC servo motors are adopted as the driver of the mechanism. The system uses an inertial gyro sensor as the feedback of the angular position. Software and hardware of the platform were developed. The full closed-loops control structure based on Advantech IPC with NI multifunction data acquisition card(PCI-6230), including current loop, velocity loop and angular position loop, gets wide speed range and high precision for angular tracking. Control software was the Matlab with embedded real-time QuaRC. Experiment results meet the technical index and precision requirement, and illustrate the practicability and effectiveness of the scheme.

Applying Stochastic Method in Engineering Design Under Uncertainty

2010 ◽  
Author(s):  
Yosef Amir
Keyword(s):  
Stochastic Optimization ◽  
Engineering Design ◽  
Position Control ◽  
Single Point ◽  
Angular Position ◽  
Bolted Joints ◽  
Stochastic Method ◽  
Deterministic Approach ◽  
First Case ◽  
Design Case

Very often design engineer uses a single-point or deterministic approach. The design modeling involves using a single “best-guess” estimate of each variable within a model to determine the model’s outcome(s). The deterministic approach often leads the engineer to make unjustified assumptions and inherent design risk decisions. To improve this design process, this paper proposes applying a stochastic method in engineering design particularly, designs under uncertainty. This paper presents three design cases of applying a stochastic method by using a Monte Carlo simulation. The first case presents a Bolted Joints (BJ) design; prediction of a bolt preload to prevent a joint of slipping investigated for a confidence of 99.97% certainty. This BJ design case demonstrates how to overcome the obstacles that exist in a deterministic Bolted Joints analysis. The variables included in this investigation are the variations of coefficient of friction, preload scatter, Bolt and the Joint geometry. The second design case investigates the angular position control of Four Bars Mechanism (FBM). In this case, the paper shows how to quantify the design risk of the real FBM angular position for a given resolution spec. Sensitivity analysis uses after each simulation to identify the driver parameters influencing the angular position of the FBM. The dominant parameters influencing the design analysis include: bars tolerance variations and an actuator driver backlash. The third case of engineering design demonstrates a stochastic optimization of a flat spring design. The goal of this stochastic optimization is to achieve the maximum spring Specific_Resilience. The optimal solution of this optimization is to select the best material of six given materials and spring geometry that fit within a given restricted envelope.

Resolution and measurement in the scanning electron microscope

1987 ◽  
Vol 45 ◽  
pp. 534-537 ◽  
Author(s):  
Michael T. Postek
Keyword(s):  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Engineering Design ◽  
Resolving Power ◽  
Practical Applications ◽  
Instrument Resolution ◽  
Accurate Definition ◽  
Definition Of ◽  
Scanning Electron ◽  
Better Than

The term ultimate resolution or resolving power is the very best performance that can be obtained from a scanning electron microscope (SEM) given the optimum instrumental conditions and sample. However, as it relates to SEM users, the conventional definitions of this figure are ambiguous. The numbers quoted for the resolution of an instrument are not only theoretically derived, but are also verified through the direct measurement of images on micrographs. However, the samples commonly used for this purpose are specifically optimized for the measurement of instrument resolution and are most often not typical of the sample used in practical applications.SEM RESOLUTION. Some instruments resolve better than others either due to engineering design or other reasons. There is no definitively accurate definition of how to quantify instrument resolution and its measurement in the SEM.

Resolution assessment from spectral signal-to-noise ratios

1987 ◽  
Vol 45 ◽  
pp. 746-747
Author(s):  
M. Unser ◽  
B.L. Trus ◽  
A.C. Steven
Keyword(s):  
Electron Microscopy ◽  
Limiting Factor ◽  
Biological Macromolecules ◽  
Signal To Noise ◽  
Differential Phase ◽  
Traditional Measure ◽  
Spectral Signal ◽  
Two Measures ◽  
Diffraction Patterns ◽  
Averaging Techniques

Since the resolution-limiting factor in electron microscopy of biological macromolecules is not instrumental, but is rather the preservation of structure, operational definitions of resolution have to be based on the mutual consistency of a set of like images. The traditional measure of resolution for crystalline specimens in terms of the extent of periodic reflections in their diffraction patterns is such a criterion. With the advent of correlation averaging techniques for lattice rectification and the analysis of non-crystalline specimens, a more general - and desirably, closely compatible - resolution criterion is needed. Two measures of resolution for correlation-averaged images have been described, namely the differential phase residual (DPR) and the Fourier ring correlation (FRC). However, the values that they give for resolution often differ substantially. Furthermore, neither method relates in a straightforward way to the long-standing resolution criterion for crystalline specimens.

Simulations of high-resolution images of amorphous silicon films

1986 ◽  
Vol 44 ◽  
pp. 544-545
Author(s):  
G. Y. Fan ◽  
J. M. Cowley
Keyword(s):  
Electron Microscope ◽  
High Frequency ◽  
Fourier Transformation ◽  
Amorphous Materials ◽  
Low Frequency ◽  
Chromatic Aberration ◽  
Structure Information ◽  
Frequency Components ◽  
High Resolution Images ◽  
Spatial Frequency Spectrum

It is well known that the structure information on the specimen is not always faithfully transferred through the electron microscope. Firstly, the spatial frequency spectrum is modulated by the transfer function (TF) at the focal plane. Secondly, the spectrum suffers high frequency cut-off by the aperture (or effectively damping terms such as chromatic aberration). While these do not have essential effect on imaging crystal periodicity as long as the low order Bragg spots are inside the aperture, although the contrast may be reversed, they may change the appearance of images of amorphous materials completely. Because the spectrum of amorphous materials is continuous, modulation of it emphasizes some components while weakening others. Especially the cut-off of high frequency components, which contribute to amorphous image just as strongly as low frequency components can have a fundamental effect. This can be illustrated through computer simulation. Imaging of a whitenoise object with an electron microscope without TF limitation gives Fig. 1a, which is obtained by Fourier transformation of a constant amplitude combined with random phases generated by computer.

Visual Evoked-Response Correlates of Speechreading Performance in Normal-Hearing Adults

1983 ◽  
Vol 26 (1) ◽  
pp. 2-9 ◽  
Author(s):  
Vincent J. Samar ◽  
Donald G. Sims
Keyword(s):  
Multiple Correlation Coefficient ◽  
Evoked Response ◽  
Multiple Correlation ◽  
Potential Significance ◽  
Visual Evoked Response ◽  
Latency Measure ◽  
Two Measures ◽  
Components Analysis ◽  
The Relationship ◽  
Visual Evoked

The relationship between the latency of the negative peak occurring at approximately 130 msec in the visual evoked-response (VER) and speechreading scores was investigated. A significant product-moment correlation of -.58 was obtained between the two measures, which confirmed the fundamental effect but was significantly weaker than that previously reported in the literature (-.90). Principal components analysis of the visual evoked-response waveforms revealed a previously undiscovered early VER component, statistically independent of the latency measure, which in combination with two other components predicted speechreading with a multiple correlation coefficient of S4. The potential significance of this new component for the study of individual differences in speechreading ability is discussed.

Reaction Time and Brain Waves in Omitted Stimulus Tasks

2010 ◽  
Vol 24 (1) ◽  
pp. 1-6 ◽  
Author(s):  
Oscar H. Hernández ◽  
Muriel Vogel-Sprott
Keyword(s):  
Reaction Time ◽  
Cognitive Processes ◽  
Young Male ◽  
Event Related Potential ◽  
Auditory Stimuli ◽  
Motor Action ◽  
Cognitive Component ◽  
Sensory Modalities ◽  
Two Measures ◽  
Somatosensory Stimuli

A missing stimulus task requires an immediate response to the omission of a regular recurrent stimulus. The task evokes a subclass of event-related potential known as omitted stimulus potential (OSP), which reflects some cognitive processes such as expectancy. The behavioral response to a missing stimulus is referred to as omitted stimulus reaction time (RT). This total RT measure is known to include cognitive and motor components. The cognitive component (premotor RT) is measured by the time from the missing stimulus until the onset of motor action. The motor RT component is measured by the time from the onset of muscle action until the completion of the response. Previous research showed that RT is faster to auditory than to visual stimuli, and that the premotor of RT to a missing auditory stimulus is correlated with the duration of an OSP. Although this observation suggests that similar cognitive processes might underlie these two measures, no research has tested this possibility. If similar cognitive processes are involved in the premotor RT and OSP duration, these two measures should be correlated in visual and somatosensory modalities, and the premotor RT to missing auditory stimuli should be fastest. This hypothesis was tested in 17 young male volunteers who performed a missing stimulus task, who were presented with trains of auditory, visual, and somatosensory stimuli and the OSP and RT measures were recorded. The results showed that premotor RT and OSP duration were consistently related, and that both measures were shorter with respect to auditory stimuli than to visual or somatosensory stimuli. This provides the first evidence that the premotor RT is related to an attribute of the OSP in all three sensory modalities.

A Reassessment of Suicide Measurement

Crisis ◽  
2009 ◽  
Vol 30 (1) ◽  
pp. 6-12 ◽  
Author(s):  
D.P. Doessel ◽  
Ruth F.G. Williams ◽  
Harvey Whiteford
Keyword(s):  
Causes Of Death ◽  
Motor Vehicle ◽  
Years Of Life Lost ◽  
Health Prevention ◽  
Prevention Strategies ◽  
Vehicle Accidents ◽  
The Social ◽  
Evaluation Exercise ◽  
Two Measures ◽  
Circulatory Diseases

Background. Concern with suicide measurement is a positive, albeit relatively recent, development. A concern with “the social loss from suicide” requires careful attention to appropriately measuring the phenomenon. This paper applies two different methods of measuring suicide data: the conventional age-standardized suicide (count) rate; and the alternative rate, the potential years of life lost (PYLL) rate. Aims. The purpose of applying these two measures is to place suicide in Queensland in a historical and comparative (relative to other causes of death) perspective. Methods. Both measures are applied to suicide data for Queensland since 1920. These measures are applied also to two “largish” causes of death and two “smaller” causes of death, i.e., circulatory diseases, cancers, motor vehicle accidents, suicide. Results. The two measures generate quite different pictures of suicide in Queensland: Using the PYLL measure, suicide is a quantitatively larger issue than is indicated by the count measure. Conclusions. The PYLL measure is the more appropriate measure for evaluation exercise of public health prevention strategies. This is because the PYLL measure is weighted by years of life lost and, thus, it incorporates more information than the count measure which implicitly weights each death with a somewhat partial value, viz. unity.

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