Research on Opening and Closing Synchronization of Flexible Hatch on Space Shuttle

2018 ◽  
Vol 12 (3) ◽  
pp. 55-68
Author(s):  
Yue Wang ◽  
Hong Liu ◽  
Bo Peng
Keyword(s):  
Space Shuttle ◽  
Basic Theory ◽  
Flexible Body ◽  
Position Accuracy ◽  
Space Industry ◽  
Key Points ◽  
Substitution Principle ◽  
Opening And Closing

The space industry is developing rapidly, specifically with the development of the space shuttle. The position accuracy of the shuttle hatch is always a key problem when the space shuttle is in orbit. When hatch position accuracy meets the requirement of the central lock acquisition domain, the central lock can capture and lock, otherwise it will cause the hatch to not close properly. Aiming at this problem, this article solves it by using the basic theory of flexible body ADAMS. First, composite hatches are converted into an equivalent shell by using the equal stiffness substitution principle, deriving the neutral file (MNF) of the hatch by a classical module in ANSYS, and testing synchronization and accuracy of it under the condition of ideal rigidity and flexibility. Eventually, we obtain the curve of motion displacement at key points, then we can estimate whether the synchronization and accuracy of the hatch meets the requirements.

Flexible Body Grasping Simulation in ADAMS

2014 ◽  
Vol 487 ◽  
pp. 509-512
Author(s):  
Yu Zhang ◽  
Zhong Jun Fu ◽  
Hui Fang Liu
Keyword(s):  
System Dynamics ◽  
Simulation Model ◽  
Elastic Deformation ◽  
System Simulation ◽  
Difficult Problem ◽  
Basic Theory ◽  
Flexible Body ◽  
Dynamics Analysis ◽  
Flexible Bodies ◽  
Data Basis

Analysis of Flexible Body is a difficult problem in system dynamics analysis. In the paper, the basic theory of ADAMS flexible body and some methods of adding flexible bodies to a model are introduced. And build a system simulation model. Through manipulator grasping tomatoes examples verify the effectiveness of ADAMS flexible body grasp simulation, provide stress and elastic deformation data basis for manipulator grasping flexible body.

A New Method of Line Feature Generalization Based on Shape Characteristic Analysis

2011 ◽  
Vol 18 (4) ◽  
pp. 597-606 ◽  
Author(s):  
Hongshan Nie ◽  
Zhijian Huang
Keyword(s):  
Adaptive Threshold ◽  
Experimental Results ◽  
New Method ◽  
Characteristic Analysis ◽  
Line Feature ◽  
Shape Characteristic ◽  
Position Accuracy ◽  
Threshold Algorithm ◽  
Key Points ◽  
Line Features

A New Method of Line Feature Generalization Based on Shape Characteristic Analysis This paper presents a piecewise line generalization algorithm (PG) based on shape characteristic analysis. An adaptive threshold algorithm is used to detect all corners, from which key points are selected. The line is divided into some segments by the key points and generalized piecewise with the Li-Openshaw algorithm. To analyze the performance, line features with different complexity are used. The experimental results compared with the DP algorithm and the Li-Openshaw algorithm show that the PG has better performance in keeping the shape characteristic with higher position accuracy.

scholarly journals Shuttle Diplomacy

1999 ◽  
Vol 121 (03) ◽  
pp. 52-55
Author(s):  
Gale Morrison
Keyword(s):  
Control Systems ◽  
Research Council ◽  
Space Shuttle ◽  
National Research Council ◽  
Liquid Oxygen ◽  
Hazardous Material ◽  
Design Review ◽  
Key Points

The article highlights key points of a special National Research Council (NRC) committee on Space Shuttle upgrades’ ‘Upgrading the Space Shuttle’ report. The NRC committee reviewed two $1 billion-plus proposals for changing what NASA uses to propel the orbiters to space, and found that these could be broached only if more flights were planned, much more design review was done, and the Shuttle would be in service after 2012. The committee used NASA's grouping of the proposed upgrades into phases, with one being the least expensive, time-consuming, and risky, and four being the most costly, long term, and risk-prone. The committee studied another upgrade that would eliminate a hazardous material. The upgrade would modify the Shuttle's orbital manoeuvring and reaction control systems to use liquid oxygen and ethanol propellants instead of current engines' toxic N2O4 and monomethyl hydrazine propellants.

The effect of back-melting on the continuity of crystallographic orientation and composition in HgZnTe

1992 ◽  
Vol 50 (2) ◽  
pp. 1696-1697
Author(s):  
H.J. Zuo ◽  
M.W. Price ◽  
R.D. Griffin ◽  
R.A. Andrews ◽  
G.M. Janowski
Keyword(s):  
Directional Solidification ◽  
Space Shuttle ◽  
Solidification Process ◽  
Space Experiment ◽  
Infrared Detection ◽  
Directionally Solidified ◽  
Crystallographic Defects ◽  
Semiconducting Alloys ◽  
Uniform Composition ◽  
Growth Experiments

The II-VI semiconducting alloys, such as mercury zinc telluride (MZT), have become the materials of choice for numerous infrared detection applications. However, compositional inhomogeneities and crystallographic imperfections adversly affect the performance of MZT infrared detectors. One source of imperfections in MZT is gravity-induced convection during directional solidification. Crystal growth experiments conducted in space should minimize gravity-induced convection and thereby the density of related crystallographic defects. The limited amount of time available during Space Shuttle experiments and the need for a sample of uniform composition requires the elimination of the initial composition transient which occurs in directionally solidified alloys. One method of eluding this initial transient involves directionally solidifying a portion of the sample and then quenching the remainder prior to the space experiment. During the space experiment, the MZT sample is back-melted to exactly the point at which directional solidification was stopped on earth. The directional solidification process then continues.

Autism and Neurodiversity: Addressing Concerns and Offering Implications for the School-Based Speech-Language Pathologist

2020 ◽  
pp. 1-7
Author(s):  
Laura S. DeThorne ◽  
Kelly Searsmith
Keyword(s):  
Service Provision ◽  
Individualized Education Program ◽  
Institutional Constraints ◽  
Individualized Education ◽  
Existing Structures ◽  
Eligibility Determination ◽  
Speech Language Pathologist ◽  
School Based ◽  
Key Points ◽  
C Center

Purpose The purpose of this article is to address some common concerns associated with the neurodiversity paradigm and to offer related implications for service provision to school-age autistic students. In particular, we highlight the need to (a) view first-person autistic perspectives as an integral component of evidence-based practice, (b) use the individualized education plan as a means to actively address environmental contributions to communicative competence, and (c) center intervention around respect for autistic sociality and self-expression. We support these points with cross-disciplinary scholarship and writings from autistic individuals. Conclusions We recognize that school-based speech-language pathologists are bound by institutional constraints, such as eligibility determination and Individualized Education Program processes that are not inherently consistent with the neurodiversity paradigm. Consequently, we offer examples for implementing the neurodiversity paradigm while working within these existing structures. In sum, this article addresses key points of tension related to the neurodiversity paradigm in a way that we hope will directly translate into improved service provision for autistic students. Supplemental Material https://doi.org/10.23641/asha.13345727

Sign in / Sign up

Export Citation Format

Share Document