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Dynamic Modeling of a Quadrotor UAV Transporting a Variable Mass Payload Suspended by Continuous Flexible Cable
, M.Sc. Thesis Sharif University of Technology ; Saghafi, Fariborz (Supervisor)
Abstract
Quadrotors are one of the most popular unmanned aerial vehicle (UAVs) that has been subject of extensive research in recent years. One of the most important applications of these aerial vehicles is transporting a cable-suspended payload from one point to another. The major challenge in modeling of this system is dynamic coupling which exist between all components of the system i.e. payload, cable and quadrotor. The purpose of this research is mathematical modeling and dynamic analysis of the system in presence of this dynamic coupling and considering the effects of cable's flexibility. In this regard, it is assumed that the payload has variable mass. In this thesis, in the first step, by...
Dynamic Analysis and Control of Transport Quadrotors in the Presence of Loads Generating Stochastic Forces
, Ph.D. Dissertation Sharif University of Technology ; Saghafi, Fariborz (Supervisor)
Abstract
In this research, inspired by the flight control of birds of prey in grasping living creatures, a precise dynamic analysis and tracking control of transport quadrotors in capturing and transporting force-generating objects in the presence of intense parametric and non-parametric uncertainties are discussed. In the first step, the origin of the forces and moments produced by the oscillatory objects is described through presenting a precise model. In the next step, an extended hybrid model of a hunting quadrotor, cable-transport quadrotor and a creative one as net-throwing aerial vehicle (NTAV) in different flight phases (Pursuit, Capturing/Joining and Transporting) is extracted and the...
Generalized Robust Control Approach for an Aerial Robot in Grasping Oscillatory Objects
, Article Iranian Conference on Electrical Engineering, ICEE ; Issue 2024 , 2024 ; 21647054 (ISSN) ; Saghafi, F ; Sharif University of Technology
2024
Abstract
Scrutinizing the problem of rapid grasping by an articulated aerial robot, it is inferred that the dynamics of the system is substantially affected at the moment of capturing. The problem intensifies when the object similar to trapped creatures in the claws of birds of prey generates stochastic forces and moments with unknown limits. This issue beside model simplification for controller design cause strong disturbances and uncertainties that can lead to system's instability and collapse. In this study, by presenting a detailed mathematical model of a hunting quadrotor after grasping an oscillatory object in planar motion, a robust controller is designed for the under-actuated flying vehicle...
Object Recognition in RGB-D Images
, M.Sc. Thesis Sharif University of Technology ; Moghadasi, Reza (Supervisor) ; Mirshams Shahshahan, Mehrdad (Co-Advisor)
Abstract
Today with the availability of cheap depth sensor, processing point clouds produced by these sensors and extracting geometric features is an active field of computer vision. Object recognition is a basic computer vision issues that even with considerable research has remained as a challenge. In these thesis we have studied methods of utilizing depth images and geometric information of point clouds in order to extract geometric features from point clouds and have introduces a set of new geometric features using Normal Orientation Histogram. Also a novel and efficient method for segmentation of point cloud of indoor scenes is proposed. Experimental results depict that our proposed methods have...
Learning of Shape Classes
, M.Sc. Thesis Sharif University of Technology ; Razvan, Mohammad Reza (Supervisor) ; Mirshams Shahshahani, Mehrdad (Co-Advisor)
Abstract
Learning of shape classes from a set of given data is of special practical importance in computer vision. Large variations in the surrounding objects makes the problem of shape learning a very di°cult one. These di°culties may vary according to diferences in pose and part articulations of shapes. Despite all of the problems, large applications of this problem in areas such as tracking, object recognition and text recognition inspires many groups to work on it. In this thesis we aim to investigate a solution for this problem