Design Optimization for the Stability of Concentric Tube Robots

2021 ◽  
pp. 1-1
Author(s):  
Kevin Ai Xin Jue Luo ◽  
Jongwoo Kim ◽  
Thomas Looi ◽  
James Drake
Keyword(s):  
Design Optimization ◽  
Concentric Tube Robots ◽  
The Stability

scholarly journals Design optimization of multi-objective proportional–integral–derivative controllers for enhanced handling quality of a twin-engine, propeller-driven airplane

2020 ◽  
Vol 12 (6) ◽  
pp. 168781402092317
Author(s):  
Mohsen Rostami ◽  
Joon Chung ◽  
Hyeong Uk Park
Keyword(s):  
Genetic Algorithm ◽  
Design Optimization ◽  
Proportional Integral Derivative ◽  
Optimum Result ◽  
Proportional Integral ◽  
Multi Objective ◽  
Directional Motion ◽  
The Stability ◽  
Handling Quality

Herein, the design optimization of multi-objective controllers for the lateral–directional motion using proportional–integral–derivative controllers for a twin-engine, propeller-driven airplane is presented. The design optimization has been accomplished using the genetic algorithm and the main goal was to enhance the handling quality of the aircraft. The proportional–integral–derivative controllers have been designed such that not only the stability of the lateral–directional motion was satisfied but also the optimum result in longitudinal trim condition was achieved through genetic algorithm. Using genetic algorithm optimization, the handling quality was improved and placed in level 1 from level 2 for the proposed aircraft. A comprehensive sensitivity analysis to different velocities, altitudes and centre of mass positions is presented. Also, the performance of the genetic algorithm has been compared to the case where the particle swarm optimization tool is implemented. In this work, the aerodynamic coefficients as well as the stability and control derivatives were predicted using analytical and semi-empirical methods validated for this type of aircraft.

scholarly journals The Stability and Design Optimization of Qiyun Pit Slope Based on Reliability Theory

2018 ◽  
Vol 2 (2) ◽  
pp. 11-17
Author(s):  
Ding Jihui ◽  
◽  
Xiang Mengjia ◽  
Shen Yu ◽  
Wei Yaxing ◽  
...  
Keyword(s):  
Design Optimization ◽  
Reliability Theory ◽  
The Stability

Design of Concentric Tube Robots Using Tube Patterning for Follow-The-Leader Deployment

2020 ◽  
Vol 13 (1) ◽  
Author(s):  
Cédric Girerd ◽  
Thomas Schlinquer ◽  
Nicolas Andreff ◽  
Pierre Renaud ◽  
Kanty Rabenorosoa
Keyword(s):  
Design Process ◽  
Constant Curvature ◽  
Stability Criterion ◽  
Medical Applications ◽  
Application Field ◽  
Concentric Tube Robots ◽  
Constrained Environments ◽  
The Stability

Abstract Concentric tube robots (CTRs) have a great potential for use in medical applications. Coupled with a follow-the-leader (FTL) deployment, they allow navigation in constrained environments. However, they are subject to instabilities if one makes use of high curvatures for the tubes, long overlapping lengths of their curved sections, or long transmission lengths. One approach to improve their stability is to pattern the tubes of which they are composed by local removals of material along their lengths. Applying patterns on tubes was proved to be of interest for given deployed lengths of a CTR. In this article, we present a method to enlarge the application field of CTRs that deploy in a follow-the-leader manner, by integrating tube patterning in the design process, with a stability criterion. Our method allows the designer to determine a custom pattern geometry to theoretically ensure the stability of CTRs made of any number of constant curvature tubes, for a complete FTL deployment sequence, and while respecting a desired shape during deployment.

Numerical Simulation and Design Optimization of Anchor Bolt-Sash Girder Support for Expansive Soil Cutting Slope

2015 ◽  
Vol 744-746 ◽  
pp. 547-550
Author(s):  
Hong Zhang ◽  
Guo Jun Sheng ◽  
Wen Qing Wu
Keyword(s):  
Numerical Simulation ◽  
Design Optimization ◽  
Expansive Soil ◽  
Original Design ◽  
Cutting Slope ◽  
Calculation Results ◽  
Soil Cutting ◽  
Anchor Bolts ◽  
The Stability ◽  
Vertical Spacing

The reinforcement of expansive soil cutting slope has been a difficulty for the construction industry. This study selected Wanyi Expressway as the construction background and used finite difference method for the numerical simulation and design optimization of expansive soil cutting slope reinforced by sash girder anchor bolts. Calculation results show that the cutting slope ratio is closely related to the stability of the expansive soil cutting slope and that the length, set angle, and vertical spacing of the anchor bolts significantly influence the deformation of the cutting slope. The original design plan was optimized according to the calculation results, and a positive effect in plan execution was achieved. This study may serve as a reference for other similar construction designs.

Open discussion

1982 ◽  
Vol 99 ◽  
pp. 605-613
Author(s):  
P. S. Conti
Keyword(s):  
Buenos Aires ◽  
Large Mass ◽  
List Type ◽  
Common Phenomenon ◽  
Open Discussion ◽  
The Stability ◽  
Ring Nebulae

Conti: One of the main conclusions of the Wolf-Rayet symposium in Buenos Aires was that Wolf-Rayet stars are evolutionary products of massive objects. Some questions:–Do hot helium-rich stars, that are not Wolf-Rayet stars, exist?–What about the stability of helium rich stars of large mass? We know a helium rich star of ∼40 MO. Has the stability something to do with the wind?–Ring nebulae and bubbles : this seems to be a much more common phenomenon than we thought of some years age.–What is the origin of the subtypes? This is important to find a possible matching of scenarios to subtypes.

Symmetric Multistep Methods Revisited: II. Numerical Experiments

1999 ◽  
Vol 173 ◽  
pp. 309-314 ◽  
Author(s):  
T. Fukushima
Keyword(s):  
Multistep Methods ◽  
Computational Time ◽  
Integration Time ◽  
Implicit Methods ◽  
Symmetric Methods ◽  
Celestial Bodies ◽  
The Stability ◽  
Predictor Corrector ◽  
Symmetric Multistep Methods ◽  
Integration Errors

AbstractBy using the stability condition and general formulas developed by Fukushima (1998 = Paper I) we discovered that, just as in the case of the explicit symmetric multistep methods (Quinlan and Tremaine, 1990), when integrating orbital motions of celestial bodies, the implicit symmetric multistep methods used in the predictor-corrector manner lead to integration errors in position which grow linearly with the integration time if the stepsizes adopted are sufficiently small and if the number of corrections is sufficiently large, say two or three. We confirmed also that the symmetric methods (explicit or implicit) would produce the stepsize-dependent instabilities/resonances, which was discovered by A. Toomre in 1991 and confirmed by G.D. Quinlan for some high order explicit methods. Although the implicit methods require twice or more computational time for the same stepsize than the explicit symmetric ones do, they seem to be preferable since they reduce these undesirable features significantly.

Uniformity of Magnification from Different Electron Microscopes

1967 ◽  
Vol 25 ◽  
pp. 32-33
Author(s):  
Godfrey C. Hoskins ◽  
V. Williams ◽  
V. Allison
Keyword(s):  
Diffraction Grating ◽  
The Other ◽  
Carbon Replica ◽  
Electron Microscopes ◽  
The Stability

The method demonstrated is an adaptation of a proven procedure for accurately determining the magnification of light photomicrographs. Because of the stability of modern electrical lenses, the method is shown to be directly applicable for providing precise reproducibility of magnification in various models of electron microscopes.A readily recognizable area of a carbon replica of a crossed-line diffraction grating is used as a standard. The same area of the standard was photographed in Phillips EM 200, Hitachi HU-11B2, and RCA EMU 3F electron microscopes at taps representative of the range of magnification of each. Negatives from one microscope were selected as guides and printed at convenient magnifications; then negatives from each of the other microscopes were projected to register with these prints. By deferring measurement to the print rather than comparing negatives, correspondence of magnification of the specimen in the three microscopes could be brought to within 2%.

Effect of Improved ThO2 Particle Dispersion in Nickel on High-Temperature Strength

1970 ◽  
Vol 28 ◽  
pp. 444-445
Author(s):  
E. R. Kimmel ◽  
H. L. Anthony ◽  
W. Scheithauer
Keyword(s):  
High Temperature ◽  
Metal Matrix ◽  
Oxide Particle ◽  
Oxide Phase ◽  
Dislocation Motion ◽  
Particle Dispersion ◽  
High Temperature Strength ◽  
Strengthening Effect ◽  
Oxide Particles ◽  
The Stability

The strengthening effect at high temperature produced by a dispersed oxide phase in a metal matrix is seemingly dependent on at least two major contributors: oxide particle size and spatial distribution, and stability of the worked microstructure. These two are strongly interrelated. The stability of the microstructure is produced by polygonization of the worked structure forming low angle cell boundaries which become anchored by the dispersed oxide particles. The effect of the particles on strength is therefore twofold, in that they stabilize the worked microstructure and also hinder dislocation motion during loading.

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