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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
21

Navigation And Path Planning Of An Unmanned Underwater Vehicle

Gul, Ugur Dogan 01 September 2012 (has links) (PDF)
Due to the conditions peculiar to underwater, distinctive approaches are required to solve the navigation and path planning problem of an unmanned underwater vehicle (UUV). In this study, first of all, a detailed 6 degrees-of-freedom (DOF) mathematical model is formed, including the coupled non-linear forces and moments acting on an underwater vehicle. The hydrodynamic coefficients which correspond to the geometry of the vehicle which the model is based on are calculated using the strip theory. After the mathematical model is obtained, by applying appropriate linearization on the model, &ldquo / Linear Quadratic Regulator (LQR)&rdquo / control method is implemented to govern the surge, heave, pitch and yaw motions of the underwater vehicle. Path planning algorithm of the vehicle is based on tracking the waypoints. Permutation of the waypoints is obtained by solving the &ldquo / Travelling Salesman Problem (TSP)&rdquo / via genetic algorithm. Linked with that, &ldquo / Rapidly-Exploring Random Trees (RRT)&rdquo / algorithm is introduced into the path planning algorithm to avoid collisions in environments with obstacles. Underwater navigation solution is based on the &ldquo / Inertial Navigation System (INS)&rdquo / outputs, located on the vehicle. To correct the long-term drift of the inertial solution, &ldquo / Kalman Filter&rdquo / based integration algorithm is used and external aids such as &ldquo / Global Navigation Satellite System (GNSS)&rdquo / , &ldquo / Ultra-Short Baseline (USBL)&rdquo / acoustic navigation system and attitude sensors have been utilized. The control method, path planning and navigation algorithms used in this study are verified by simulation results.
22

Design And Control Of A Self-parking Model Car

Avgan, Utku 01 October 2003 (has links) (PDF)
A fuzzy logic control algorithm for self parking of a model car has been developed and an embedded controller hardware has been designed, manufactured and programmed to control parking maneuvers of a model car within the scope of this thesis study. The model car chassis consists of a DC motor actuated traction system and a servomotor actuated steering mechanism. Position data and parking place data is obtained by a sensory system. A stepper motor driven rotary table is designed and assembled to the model car chassis for positioning of the sensory system. The controller hardware includes all the required peripherals for interfacing to the motors and sensory system. A visual computer program running in PC environment is developed in order to simulate the control characteristics of the fuzzy logic algorithm. The program allows the user to generate fuzzy sets and fuzzy set members and allows the user to define membership functions and fuzzy rules. Once an appropriate control characteristic is obtained, all the parameters can be exported to a file in order to be downloaded to the controller.
23

Modeling And Simulation Of A Navigation System With An Imu And A Magnetometer

Kayasal, Ugur 01 September 2007 (has links) (PDF)
In this thesis, the integration of a MEMS based inertial measurement unit and a three axis solid state magnetometer are studied. It is a fact that unaided inertial navigation systems, especially low cost MEMS based navigation systems have a divergent behavior. Nowadays, many navigation systems use GPS aiding to improve the performance, but GPS may not be applicable in some cases. Also, GPS provides the position and velocity reference whereas the attitude information is extracted through estimation filters. An alternative reference source is a three axis magnetometer, which provides direct attitude measurements. In this study, error propagation equations of an inertial navigation system are derived / measurement equations of magnetometer for Kalman filtering are developed / the unique method to self align the MEMS navigation system is developed. In the motion estimation, the performance of the developed algorithms are compared using a GPS aided system and magnetometer aided system. Some experiments are conducted for self alignment algorithms.
24

Modeling And Motion Simulation Of An Underwater Vehicle

Kucuk, Koray 01 September 2007 (has links) (PDF)
This thesis involves modeling, controller design, and test case simulations for an underwater vehicle. Firstly, a complete dynamic model of the vehicle is developed with six degrees of freedom. The model includes the nonlinearities associated with the hydrodynamic forces and moments. The thrusters of the vehicle are also modeled. Then, using appropriate linearizations of the model, position and rate controllers are designed for the forward, downward, and turning motions of the vehicle. Finally, the designed controllers are tested for various maneuvers by means of simulations using the nonlinear dynamic model of the vehicle. The simulation results show that the designed controllers are quite satisfactory for the intended maneuvers.
25

Simultaneous Localization And Mapping For A Mobile Robot Operating In Outdoor Environments

Sezginalp, Emre 01 December 2007 (has links) (PDF)
In this thesis, a method to the solution of autonomous navigation problem of a robot working in an outdoor application is sought. The robot will operate in unknown terrain where there is no a priori map present, and the robot must localize itself while simultaneously mapping the environment. This is known as Simultaneous Localization and Mapping (SLAM) problem in the literature. The SLAM problem is attempted to be solved by using the correlation between range data acquired at different poses of the robot. A robot operating outdoors will traverse unstructured terrain, therefore for localization, pitch, yaw and roll angles must also be taken into account along with the (x,y,z) coordinates of the robot. The Iterative Closest Points (ICP) algorithm is used to find this transformation between different poses of the robot and find its location. In order to collect the range data, a system composing of a laser range finder and an angular positioning system is used. During localization and mapping, odometry data is fused with range data.
26

Modeling And Control Of Constrained Flexible Joint Parallel Manipulators

Ogan, Osman Can 01 February 2010 (has links) (PDF)
The purpose of the thesis is to achieve a hybrid force and motion control method of parallel manipulators working in a constrained environment, in the presence of joint flexibility that occurs at the actuated joints. A flexible joint is modeled and the equations of motion of the parallel manipulator are derived by using the Lagrange formulation. The structural damping of the active joints, viscous friction at the passive joints and the rotor damping are also considered in the model. It is shown that in a flexible joint manipulator, the acceleration level inverse dynamic equations are singular because the control torques do not have instantaneous effect on the manipulator end-effector contact forces and accelerations due to the flexibility. Implicit numerical integration methods are utilized for solving the singular equations. As a case study, a two legged constrained planar parallel manipulator with three degrees of freedom is simulated to illustrate the performance of the method.
27

Design, modelling and simulation of 2 novel 6 DOF hybrid machines.

Shaik, Ahmed Asif. January 2012 (has links)
Industrial robot arms are an essential part of automated manufacturing, and perform tasks such as component assembly, welding, light machining, spray painting, etc. They are highly repeatable, can be calibrated to be sufficiently accurate and they eliminate human error. The serial robot architecture is by far the most ubiquitous in modern day manufacturing, as the technology is highly refined in its current state; the machine architecture provides great dexterity and it has a large useful workspace. This architecture however does have some problems, one of which is a large machine moving mass. The primary reason for this lies in the location of its motors and gearboxes. Due to the robot's significant inertia it utilizes a large amount of energy. This thesis focused on the mechanical design, mathematical modelling and simulation of 2 robotic arm designs which had a hybrid nature. They were classified as hybrid due to the fact that their architectures departed from both the classic definitions of serial kinematics manipulators/machines (SKMs) and parallel kinematics manipulators/machines (PKMs). The primary design goal was to merge some of the advantages of both architectures, i.e. a large workspace to footprint ratio and high end-effector dexterity which was found in serial robots, combined with the low inertia of a parallel robot for improved dynamics. Serial and parallel robots were complementary, and these design goals could not co-exist in a single purist robot architecture. The designs had a full complement of 6 DOFs (degrees of freedom), 3 DOFs for spatial position of the wrist and 3 DOFs for orientation of that wrist. They also had a lower machine moving mass, a fact that was thought to improve speed and energy usage. A major contribution of this research PhD project was a comparative energy usage study, which was performed against the serial robot as a measure. This was done for both hybrid designs as well as another model which represented 2 existing patented designs. The purpose of that was to determine if lowering the machine moving mass would improve energy efficiency, and to determine which design was best. / Thesis (Ph.D.)-University of KwaZulu-Natal, Durban, 2012.
28

Knowledge transfer in robot manipulation tasks

Huckaby, Jacob O. 22 May 2014 (has links)
Technology today has progressed to the point that the true potential of robotics is beginning to be realized. However, programming robots to be robust across varied environments and objectives, in a way that is accessible and intuitive to most users, is still a difficult task. There remain a number of unmet needs. For example, many existing solutions today are proprietary, which makes widespread adoption of a single solution difficult to achieve. Also, most approaches are highly targeted to a specific implementation. But it is not clear that these approaches will generalize to a wider range of problems and applications. To address these issues, we define the Interaction Space, or the space created by the interaction between robots and humans. This space is used to classify relevant existing work, and to conceptualize these unmet needs. GTax, a knowledge transfer framework, is presented as a solution that is able to span the Interaction Space. The framework is based on SysML, a standard used in many different systems, which provides a formalized representation and verification. Through this work, we demonstrate that by generalizing across the Interaction Space, we can simplify robot programming and enable knowledge transfer between processes, systems and application domains.
29

Development Of A Mechatronics Education Desk

Erdener, Onur Alper 01 December 2003 (has links) (PDF)
In this thesis a mechatronics education desk is developed. The system developed is a low cost, versatile mechatronics education and teaching environment that aims to facilitate hands-on education of undergradutate level mechatronics students. The desk is formed of three main modules that address the needs of mechatronics education: The WorkDesk, Mechatronic Building Blocks and Experimental Setups. These parts are well designed and presented to form a complete and coordinated solution for mechatronics education. The WorkDesk is a platform devoted to the mechatronics engineering trainee, which provides mechanical, electrical and software prototyping that enables studying, testing and parts integration for mechatronic projects. The components building up the WorkDesk are selected or developed to facilitate mechatronics design and prototyping. Mechatronic building blocks necessary for mechatronics teaching are identified and selected to be a part of the system. In order to support these modules, low cost custom building blocks are also developed. These include, an autonomous mobile robot kit and a versatile interface board called ready2go. Demonstrative experiments with custom developed building blocks are also presented. Two experimental setups are developed and presented in the scope of the thesis. The setups, Intelligent Money Selector and Heater/Cooler, address and demonstrate many aspects of mechatronic systems as well as aid introducing systems approach in mechatronics education. As a consequence, a mechatronics education desk is developed and presented with many hands-on educational case studies. The system developed forms an extensible and flexible software and hardware architecture and platform that enables integration of additional mechatronics education modules.
30

Conceptual Design Of A Model Support System And Its Controller For Ankara Wind Tunnel

Ulusal, Nejat 01 December 2005 (has links) (PDF)
Ankara Wind Tunnel (AWT) operated by T&Uuml / BiTAK-SAGE is the only big sized wind tunnel in Turkey. The AWT was constructed in late 1940&rsquo / s but was not operated until 1993 when the tunnel was turned over T&Uuml / BiTAK-SAGE. Since 1993, a series of modernization work has been undergoing in order to match the demands of the 21st century. In wind tunnels, models are positioned by special mechanisms that are instrumented to get the test data specific to the test performed. Models are assembled from their rear sides on these mechanisms called model support systems in order not to influence the flow around them. In this thesis, a conceptual design of a 6 degrees-of-freedom model support system for AWT is accomplished. A detailed system model is developed for the controller design. A force controller to perform store separation tests in real time is designed, tuned, and validated with computer simulations.

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