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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.
11

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.
12

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.
13

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.
14

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.
15

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.
16

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.
17

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.
18

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.
19

Development Of Electrical And Control System Of An Unmanned Ground Vehicle For Force Feedback Teleoperation

Hacinecipoglu, Akif 01 September 2012 (has links) (PDF)
Teleoperation of an unmanned vehicle is a challenging task for human operators especially when the vehicle is out of line of sight. Improperly designed and applied display interfaces directly affect the operation performance negatively and even can result in catastrophic failures. If these teleoperation missions are human-critical then it becomes more important to improve the operator performance by decreasing workload, managing stress and improving situational awareness. This research aims to develop electrical and control system of an unmanned ground vehicle (UGV) using an All-Terrain Vehicle (ATV) and validate the development with investigation of the effects of force feedback devices on the teleoperation performance. After development, teleoperation tests are performed to verify that force feedback generated from the dynamic obstacle information of the environment improves teleoperation performance. Results confirm this statement and the developed UGV is verified for future research studies. Development of UGV, algorithms and real system tests are included in this thesis.
20

Novel Position Measurement And Estimation Methods For Cnc Machine Systems

Kilic, Ergin 01 August 2007 (has links) (PDF)
Precision control of translational motion is vital for many CNC machine tools as the motion of the machinery affects the dimensional tolerance of the manufactured goods. However, the direct measurement along with the accurate motion control of machine usually requires relatively expensive sensors i.e. potentiometers, linear scales, laser interferometers. Hence, this study attempts to develop reference models utilizing low-cost sensors (i.e. rotary encoders) for accurate position estimation. First, an indirect measurement performance is investigated on a Timing Belt driven carriage by a DC Motor with a backlash included Gearbox head. An advanced interpolated technique is proposed to compensate the position errors while using indirect measurement to reduce the total cost. Then, a similar study was realized with a ball screw driven system. Next, a cable drum driven measurement technique is proposed to the machines which have long travel distance like plasma cutters. A test setup is proposed and manufactured to investigate the capstan drive systems. Finally, characteristics of Optical Mouse Sensors are investigated from different point of views and a test setup is proposed and manufactured to evaluate their performances in long terms. Beside all of these parts, motion control algorithms and motion control integrated circuits are designed and manufactured to realize experimental studies in a detailed manner.

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