scholarly journals Бифуркация Пуанкаре-Андронова-Хопфа в колебаниях прощелкивания составных несущих и управляющих поверхностей летательных аппаратов

2019 ◽  
Vol 45 (15) ◽  
pp. 47
Author(s):  
М.К. Тлеулинов
Keyword(s):  
Angle Of Attack ◽  
Control Surface ◽  
Phase Portraits ◽  
Shape Oscillations ◽  
Catastrophic Change ◽  
Twisting Angle ◽  
And Control ◽  
Control Surfaces

Oscillations of a catastrophic change in shape (oscillations of clicking) compound lifting and control surfaces interconnected in a statically indefinable manner are considered. The influence of the angle of attack on the nature of oscillations is investigated. The phase portraits of the twisting angle of the control surface at different angles of attack are given.

Novel Silicon Based Anodic Spark Deposition Treatment for Dental Implant

2008 ◽  
Vol 47-50 ◽  
pp. 1434-1437
Author(s):  
Lertrit Sarinnaphakorn ◽  
Patrick Mesquida ◽  
Roberto Chiesa ◽  
C. Giordano ◽  
Michael Fenlon ◽  
...  
Keyword(s):  
Pure Titanium ◽  
Biological Response ◽  
Titanium Implants ◽  
Control Surface ◽  
Commercially Pure Titanium ◽  
Titanium Surfaces ◽  
Silicon Based ◽  
And Control ◽  
Control Surfaces

Surface treated titanium implants are increasingly being used in dental and orthopaedic applications. This study examined the biological response of primary human alveolar osteoblast (aHOB) cells to a novel silicon based anodic spark deposition treated titanium surfaces. Three different titanium surfaces were investigated: anodic spark deposition (ASD) with silicon based (ASDSi), BioSpark™ (BS), and chemically etched (BioRough™, BR). Commercially pure titanium (cpTi) was the non-treated control surface. Physiological and biological evaluations were conducted on all test and control surfaces. Surface scanning (SEM, EDS, and AFM) confirmed a nano-topography, which was textured for all surfaces; and similar surface chemical composition (Ca and P), of significant was the Si peak on the ASDSi surface. Cell morphological study (SEM) showed good adhere and spreading over the surface, with metabolically active cells having extended filopodia. Biological response was observed with cell proliferation on all test surfaces for the period studied. Proliferation rate was seen to increase with time. This initial favourable cell response will be of benefit in the long term osseointegration of the implant surfaces.

scholarly journals Reconfiguration of Unmanned Aircraft Control System

2017 ◽  
Vol 2017 (2) ◽  
pp. 80-96
Author(s):  
Marcin Żugaj
Keyword(s):  
Control System ◽  
Unmanned Aircraft ◽  
Control Surface ◽  
Control Input ◽  
Aircraft Control ◽  
System Failures ◽  
System Reconfiguration ◽  
And Control ◽  
Control Surfaces ◽  
Aircraft Control System

Abstract Reliability of unmanned aircraft is a decisive factor for conducting air tasks in controlled airspace. One of the means used to improve unmanned aircraft reliability is reconfiguration of the control system, which will allow to maintain control over the aircraft despite occurring failures. The control system is reconfigured by using operational control surfaces, to compensate for failure consequences and to control the damaged aircraft. Development of effective reconfiguration algorithms involves utilization of a non-linear model of unmanned aircraft dynamics, in which deflection of each control surface can be controlled independently. The paper presents a method for an unmanned aircraft control system reconfiguration utilizing a linear and nonlinear model of aerodynamic loads due to control. It presents reconfiguration algorithms, which differ with used models and with optimization criteria for deflections of failure-free control surfaces. Additionally it presents results of a benchmark of the developed algorithms, for various types of control system failures and control input.

scholarly journals Fuzzy x- and s Control Charts: A Data-Adaptability and Human-Acceptance Approach

Complexity ◽  
2017 ◽  
Vol 2017 ◽  
pp. 1-17 ◽  
Author(s):  
Ming-Hung Shu ◽  
Dinh-Chien Dang ◽  
Thanh-Lam Nguyen ◽  
Bi-Min Hsu ◽  
Ngoc-Son Phan
Keyword(s):  
Surface Roughness ◽  
Control Charts ◽  
Fuzzy Numbers ◽  
Control Surface ◽  
Process Conditions ◽  
Fuzzy Data ◽  
Size Condition ◽  
Resolution Identity ◽  
And Control ◽  
Control Limits

For sequentially monitoring and controlling average and variability of an online manufacturing process, x¯ and s control charts are widely utilized tools, whose constructions require the data to be real (precise) numbers. However, many quality characteristics in practice, such as surface roughness of optical lenses, have been long recorded as fuzzy data, in which the traditional x¯ and s charts have manifested some inaccessibility. Therefore, for well accommodating this fuzzy-data domain, this paper integrates fuzzy set theories to establish the fuzzy charts under a general variable-sample-size condition. First, the resolution-identity principle is exerted to erect the sample-statistics’ and control-limits’ fuzzy numbers (SSFNs and CLFNs), where the sample fuzzy data are unified and aggregated through statistical and nonlinear-programming manipulations. Then, the fuzzy-number ranking approach based on left and right integral index is brought to differentiate magnitude of fuzzy numbers and compare SSFNs and CLFNs pairwise. Thirdly, the fuzzy-logic alike reasoning is enacted to categorize process conditions with intermittent classifications between in control and out of control. Finally, a realistic example to control surface roughness on the turning process in producing optical lenses is illustrated to demonstrate their data-adaptability and human-acceptance of those integrated methodologies under fuzzy-data environments.

scholarly journals Body Flexibility Enhances Maneuverability in the World’s Largest Predator

2018 ◽  
Vol 59 (1) ◽  
pp. 48-60 ◽  
Author(s):  
P S Segre ◽  
D E Cade ◽  
J Calambokidis ◽  
F E Fish ◽  
A S Friedlaender ◽  
...  
Keyword(s):  
Open Ocean ◽  
The Body ◽  
Long Distance ◽  
Active Surfaces ◽  
Aquatic Locomotion ◽  
And Performance ◽  
And Control ◽  
Blue Whales ◽  
Control Surfaces ◽  
Complex Trajectories

Abstract Blue whales are often characterized as highly stable, open-ocean swimmers who sacrifice maneuverability for long-distance cruising performance. However, recent studies have revealed that blue whales actually exhibit surprisingly complex underwater behaviors, yet little is known about the performance and control of these maneuvers. Here, we use multi-sensor biologgers equipped with cameras to quantify the locomotor dynamics and the movement of the control surfaces used by foraging blue whales. Our results revealed that simple maneuvers (rolls, turns, and pitch changes) are performed using distinct combinations of control and power provided by the flippers, the flukes, and bending of the body, while complex trajectories are structured by combining sequences of simple maneuvers. Furthermore, blue whales improve their turning performance by using complex banked turns to take advantage of their substantial dorso-ventral flexibility. These results illustrate the important role body flexibility plays in enhancing control and performance of maneuvers, even in the largest of animals. The use of the body to supplement the performance of the hydrodynamically active surfaces may represent a new mechanism in the control of aquatic locomotion.

scholarly journals Chaos and Control in Coronary Artery System

2012 ◽  
Vol 2012 ◽  
pp. 1-15 ◽  
Author(s):  
Yanxiang Shi
Keyword(s):  
Coronary Artery ◽  
Feedback Control ◽  
Numerical Simulations ◽  
Melnikov Method ◽  
Phase Portraits ◽  
Bifurcation Diagrams ◽  
Nonlinear Dynamical ◽  
The Road ◽  
Two Systems ◽  
And Control

Two types of coronary artery system N-type and S-type, are investigated. The threshold conditions for the occurrence of Smale horseshoe chaos are obtained by using Melnikov method. Numerical simulations including phase portraits, potential diagram, homoclinic bifurcation curve diagrams, bifurcation diagrams, and Poincaré maps not only prove the correctness of theoretical analysis but also show the interesting bifurcation diagrams and the more new complex dynamical behaviors. Numerical simulations are used to investigate the nonlinear dynamical characteristics and complexity of the two systems, revealing bifurcation forms and the road leading to chaotic motion. Finally the chaotic states of the two systems are effectively controlled by two control methods: variable feedback control and coupled feedback control.

Model reduction of aerothermodynamic for hypersonic aerothermoelasticity based on POD and Chebyshev method

2018 ◽  
Vol 233 (10) ◽  
pp. 3734-3748
Author(s):  
Yan Xiaoxuan ◽  
Han Jinglong ◽  
Zhang Bing ◽  
Yuan Haiwei
Keyword(s):  
Computational Cost ◽  
Maximum Error ◽  
Control Surface ◽  
Alternative Approach ◽  
Average Maximum ◽  
Optimization And Control ◽  
Efficient Alternative ◽  
Computational Fluid Dynamics Cfd ◽  
And Control ◽  
Proper Orthogonal

Accurate modeling of aerothermodynamics with low computational cost takes on a crucial role for the optimization and control of hypersonic vehicles. This study examines three reduced-order models (ROMs) to provide a reliable and efficient alternative approach for obtaining the aerothermodynamics of a hypersonic control surface. Coupled computational fluid dynamics (CFD) and computational thermostructural dynamics (CTSD) approaches are used to generate the snapshots for ROMs considering the interactions between aerothermodynamics, structural dynamics and heat transfer. One ROM adopts a surrogate approach named Kriging. The second ROM is constructed by the combination of Proper Orthogonal Decomposition (POD) and Kriging, namely, POD-Kriging. The accuracy of Kriging-based ROM is higher than that of POD-Kriging-based ROM, but the efficiency is lower. Therefore, to address the shortcomings of the above two approaches, a new ROM is developed that is composed of POD and modified Chebyshev polynomials, namely, POD-Chebyshev. The ROM based on POD-Chebyshev has the best precision and efficiency among the three ROMs and generally has less than 2% average maximum error for the studied problem.

Thrust Enhancement From Radial Velocity in Squid Inspired Thrusters

2012 ◽  
Author(s):  
Michael Krieg ◽  
Kamran Mohseni
Keyword(s):  
Radial Velocity ◽  
Driving Mechanism ◽  
Low Thrust ◽  
Vortex Ring Formation ◽  
Total Impulse ◽  
Fluid Jets ◽  
Force Range ◽  
And Control ◽  
Thrust Production ◽  
Control Surfaces

Squid and jellyfish generate propulsive forces by successively taking in and expelling high momentum jets of water. This method of propulsion offers several advantages to underwater vehicles/robots. The driving mechanism can be placed internal to the vehicle, reducing the drag associated with an abundance of external thrusters and control surfaces. The thrusters can generate accurate predictable forcing in the low thrust range, while still generating thrust nearly instantaneously over the entire force range. Vortex ring formation dynamics play an important role in creating thrust. It is observed that squid and jellyfish eject fluid jets which are not exactly parallel, and have a contracting velocity in the radial direction. A prototype thruster was developed which generates both parallel and converging propulsive jets. The total impulse of the jet is determined from DPIV techniques to determine the effect a non-zero radial velocity had on thrust production. The radial velocity was observed to increase the total impulse of the jet by 70% for low stroke ratio jets, and 75% for large stroke ratio jets.

Effects of Hull and Control Surface Roughness on Ship Maneuvering

2020 ◽  
pp. 1-10
Author(s):  
John C. Daidola
Keyword(s):  
Surface Roughness ◽  
Equations Of Motion ◽  
Control Surface ◽  
Ship Maneuvering ◽  
Single Screw ◽  
Operation And Maintenance ◽  
Hydrodynamic Derivatives ◽  
Turning Maneuver ◽  
And Control ◽  
Surface Vessel

The effects of hull roughness on ship maneuvering characteristics are investigated. The hydrodynamic derivatives in the equations of motion for surface vessel maneuvering are modified to incorporate roughness of the hull and rudder. Vessel lifetime roughness profiles are postulated based on construction, coatings, operation, and maintenance for a vessel life of 25 years. These are then applied to the turning maneuver for single screw cargo ships with block coefficients from .60 to .80. The implications for naval missions are discussed.

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