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Equations of motion of a ring-like robot with a flexible body and creeping-rolling motion
, Article ASME International Mechanical Engineering Congress and Exposition, Proceedings ; 2010 , pp. 191-197 ; ISBN: 9780791843833 ; Alasty, A ; Sharif University of Technology
Abstract
The robots that can move on rough terrains are very important especially in Rescue operation, exploration, etc. In this research, a mechanism is introduced for a ring-like robot with a flexible body. This robot is moved by arms which are placed radially and have Reciprocating motion in this direction. By controlling the contraction and the extension of the arms which contact lhe ground, the robot will be forced to move which is called rolling-creeping motion. The robot is stable in stationary state.; also the maximum angle which it can be stable is determined. Considering the speed of contracted arm is the input parameter, the speed of the extended arm for locomotion of the robot has been...
Unsteady Hydrodynamic Simulation of Flexible Bodies using Boundary Element Method
, Ph.D. Dissertation Sharif University of Technology ; Abbaspour Tehrani, Majid (Supervisor)
Abstract
For more than a million years, aquatic animals and specially fishes make undulatory motions in their flexible body to propel themselves. In the recent decays, scientists prove that these mechanisms are more efficient than man-made propulsion systems. A wide variety of artificial vehicles including robotfishes, ROV and etc has been manufactured with inspiring by natural creatures. The Biomimetic science which deals with the study of mechanics and hydrodynamics of living creatures is very important in developing these vehicles. In the present study, numerical software (PANEL3D®), bases on boundary integral equations of potential flow have been developed to simulate hydrodynamic performance of...
Modeling, Design and Manufacturing of Deformable Ring-Like Robot with Parametric Control of Rolling-Creeping Motion
, M.Sc. Thesis Sharif University of Technology ; Alasty, Aria (Supervisor)
Abstract
The robots that can move on rough terrains are very important especially in rescue operation, exploration of mine and etc. Since contact surfaces between the robot and the ground are unpredictable, the structure of the robot is usually unintelligible and its motion analysis is difficult. In this research, a ring-like shape robot with flexible body is proposed for motion in rough terrain, gradient paths and passing bars. The ring shape has more usages than other shapes for example as a wheel in a larger robot. Also its flexibility helps the motion particularly on rough terrains. This robot consists of a central section for setting equipments and arms around that. Being radially and...
Numerical Simulation and Hydrodynamic Investigation of Oscillating Wing Inspired by Manta Ray
, Ph.D. Dissertation Sharif University of Technology ; Abbaspour Tehrani Fard, Majid (Supervisor) ; Darbandi, Masoud (Co-Supervisor)
Abstract
It has always been a human challenge to inspire natural configurations and phenomena and benefit from their merits in improving the performances of man-made proposed aero/hydro vehicles. For example, the manta rays are known for their great swimming performances. To design and fabricate an underwater robot based on the manta ray geometry and its kinematic characteristics, it is important to initially study its hydrodynamic behavior and possibly arrive at some key design parameters, which can remarkably help to figure out an optimum geometry with high swimming performances. The main objective of this study is to focus on the merits of gliding motion inspired by the manta ray fish considering...
Adaptive 2D-path optimization of steerable bevel-tip needles in uncertain model of brain tissue
, Article 2009 WRI World Congress on Computer Science and Information Engineering, CSIE 2009, Los Angeles, CA, 31 March 2009 through 2 April 2009 ; Volume 5 , 2009 , Pages 254-260 ; 9780769535074 (ISBN) ; Torabi, M ; Sharif University of Technology
2009
Abstract
Although there are many works in which path planning of robots is studied, but path planning of the bevel-tip needles with highly flexible body is different and difficult due to unique properties of soft tissues. Real soft tissues are nonhomogeneously elastic and uncertainly deformable and hence, during needle motions the planned path changes unknowingly. In this paper, a novel adaptive path planning of bevel-tip needles inside the uncertain brain tissue is presented. The proposed approach is based on minimization of a Lyapanov energy function used as the cost function which consists of 6 partial costs: path length, number of changes in bevel direction, tissue deformation, horizontal and...
Effects of motion and structural vibration–induced loadings on the coupled dynamic response of a mono-column tension-leg-platform floating wind turbine
, Article Proceedings of the Institution of Mechanical Engineers Part M: Journal of Engineering for the Maritime Environment ; Volume 234, Issue 2 , 2020 , Pages 426-445 ; Abbaspour, M ; Tabeshpour, M. R ; Karimirad, M ; Sharif University of Technology
SAGE Publications Ltd
2020
Abstract
Floating wind turbines are subjected to highly dynamic and complicated environmental conditions leading to significant platform motions and structural vibrations during operation and survival conditions. These motions and vibrations alter the induced loading characteristics; and consequently, affect the dynamic behavior of the system. In order to better understand the influence of such motions and structural vibrations, herein elastic structural disturbance of tower, on the system behavior, the spectral and statistical characteristics of a floating wind turbine dynamic responses under operational and survival conditions are fully explored using a fully coupled...
The effective mechanical properties and the interfacial characterization of CNT reinforced nanocomposites
, Article Proceedings of SPIE - The International Society for Optical Engineering, 9 March 2009 through 11 March 2009, San Diego, CA ; Volume 7294 , 2009 ; 0277786X (ISSN); 9780819475541 (ISBN) ; Naghdabadi, R ; The International Society for Optical Engineering (SPIE) ; Sharif University of Technology
2009
Abstract
A small volume fraction of Carbon Nanotubes (CNTs) added in a polymeric matrix increases significantly the mechanical properties of the polymers. It is experimentally determined from the TEM images of CNT-based nanocomposites that nanotubes don't stand straight in their embedded matrix and they have some curvature in their shape. The load transfer mechanism between CNT and polymer matrix is also one of the most important issues which is not understood explicitly, yet. In this paper a wavy Single Walled Carbon Nanotube (SWCNT) is modeled as inclusion in a polymer matrix and its effective mechanical properties is studied. This model is based on using 3-D Representive Volume Element (RVE) with...