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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

Data Acquisition And Processing Interface Development For 3d Laser Rangefinder

Cevikbas, Orcun 01 August 2006 (has links) (PDF)
In this study, it is aimed to improve the previously developed data acquisition program which was run under DOS and 2D surface reconstruction program under Windows. A new system is set up and both data acquisition and processing software are developed to collect and process data within just one application, running under Windows. The main goal of the thesis is to acquire and process the range data taken from the laser rangefinder in order to construct the 3D image map of simple objects in different positions for indoor environments. The data acquisition program collects data in helical way. To do this, appropriate parameters for the data acquisition interface are determined. In the data processing step, it is aimed to use basic triangulation algorithms and threshold conditions to calculate resolutions, detect noisy points and segment objects from the environment for line fitting. The developed and implemented data acquisition and processing interfaces in the thesis are capable of creating 3D image map and obtaining the view of scanned environment in a short time with high accuracy.
12

Ne Design Methods For Polyhedral Linkages

Kiper, Gokhan 01 September 2006 (has links) (PDF)
This thesis analyses the existing types of polyhedral linkages and presents new linkage types for resizing polyhedral shapes. First, the transformation characteristics, most specifically, magnification performances of existing polyhedral linkages are given. Then, methods for synthesizing single degree-of-freedom planar polygonal linkages are described. The polygonal linkages synthesized are used as faces of polyhedral linkages. Next, the derivation of some of the existing linkages using the method given is presented. Finally, some designs of cover panels for the linkages are given. The Cardan Motion is the key point in both analyses of existing linkages and synthesis of new linkages.
13

Inverse Dynamics Control Of Flexible Joint Parallel Manipulators

Korkmaz, Ozan 01 December 2006 (has links) (PDF)
The purpose of this thesis is to develop a position control method for parallel manipulators so that the end effector can follow a desired trajectory specified in the task space where joint flexibility that occurs at the actuated joints is also taken into consideration. At the beginning of the study, a flexible joint is modeled, and the equations of motion of the parallel manipulators are derived for both actuator variables and joint variables by using the Lagrange formulation under three assumptions regarding dynamic coupling between the links and the actuators. These equations of motion are transformed to an input/output relation between the actuator torques and the actuated joint variables to achieve the trajectory tracking control. Moreover, the singular configurations of the parallel manipulators are explained. As a case study, a three degree of freedom, two legged planar parallel manipulator is simulated considering joint flexibility. The structural damping of the active joints, viscous friction at the passive joints and the rotor damping are also considered throughout the study. Matlab&reg / and Simulink&reg / softwares are used for the simulations. The results of the simulations reveal that steady state errors are negligibly small and good tracking performances can be achieved.
14

Inverse Dynamics Control Of Parallel Manipulators Around Singular Configurations

Ozdemir, Mustafa 01 January 2008 (has links) (PDF)
In this thesis, a technique for the motion of parallel manipulators through drive singularities is investigated. To remedy the problem of unbounded inverse dynamics solution in the neighborhood of drive singularities, an inverse dynamics controller which uses a conventional inverse dynamics control law outside the neighborhood of singularities and switches to the mode based on the formerly derived modified equations inside the neighborhood of singularities is proposed. As a result, good tracking performance is obtained while the actuator forces remain within the saturation limits of the actuators around singular configurations.
15

Human-like Robot Head Design

Olcucuoglu, Orhan 01 September 2007 (has links) (PDF)
In the thesis study, it is intended to design and manufacture an anthropomorphic robot head that can resemble human head/neck and eye movements. The designed robot head consists of a 4-DOF neck and a 4-DOF head. The head is composed of 3-DOF eyes and 1-DOF jaw. This work focuses on the head/neck and eyes therefore / the other free to move parts such as eyebrows, eyelids, ears etc. are not implemented. The general kinematic human modeling technique can be applied to facilitate the humanoid robotics design process since human anatomy can be represented as a sequence of rigid bodies connected by joints. In this study, we refer to the anthropometric data in determining the dimensions of all parts in order to have a robot head as human-like as possible. In addition, motion types, motion ranges and their velocities are considered. These factors are of great importance in imitating the human head movements as close as possible. It is intended that the developed humanoid robot head will be used as a research platform in studying fields such as / social interaction between human and robots, artificial intelligence and virtual reality. It will also be an experimental setup to conduct experiments for studying active vision systems.
16

Modular Embedded System Design / Implementation For Mechatronic Education And Research

Nursal, Ali Ozgu 01 September 2007 (has links) (PDF)
In this thesis a modular embedded system for Mechatronics education and research is designed and implemented. Four types of control boards are manufactured and related software is developed at board and PC level. A star like topology is used for boards architecture. One bridge board is responsible for handling communication between the PC and all the other boards that are connected independently to that bridge board. For PC communication Universal Seial Bus (USB), for inter peripheral communication serial peripheral interface (SPI) is used. By the use of USB and SPI, the system becomes scalable and hot pluggable. All these four boards can be used in stand alone and/or together in different applications. The system covers / general analog digital input output, several types of motor control and simple graphical display applications. The firmware and software is developed in a modular, flexible and transparent way allowing users all level accessibility. This way, the application fields and the content of the courses that will be using this system become very versatile. A simulation of hard disk reading experiment is designed and implemented to show the integral capabilities of the system. In this experiment all the boards are utilized and used together. As a result, a system is designed for Mechatronics experiments and research. A modular approach is adopted which is compsed of units that can also work in a stand-alone manner. A software library developed for the PC platform facilitates high-level usage of these cards whereas it is possible to implement custom codes on these boards. To sum up, an affordable, versitale, scalable and transparent system is developed which is specifically tailored for Mechatronics applications.
17

Development Of Dental Educational Simulation With Haptic Device

Kocak, Umut 01 September 2007 (has links) (PDF)
Virtual Reality (VR) applications in medicine had significant improvements. 3D visualization of various anatomical parts using advanced medical scanner images, anatomy education, surgery operation simulation, virtual simulator for laparoscopic skills, virtual endoscopy, psychotherapy and rehabilitation techniques are some of the VR applications in medicine. Integration of the haptic devices into VR applications increased quality of the systems. By using haptic devices, the user can not only feed information to the computer but can receive information from the computer in the form of a felt sensation on some part of the body. In this thesis a dental education simulator is developed by using a computer, a monitor, a haptic device and stereoscopic devices. The entire jaw model, all teeth and decay is modeled in the virtual environment. It is possible to diagnose the decay and remove the decay region by using different dental instruments developed in the system. Different graphical rendering methods like Marching Cubes, Ray-casting on GPU are implemented and compared. The system is used by dentists from METU Health Center and Ankara University and performance tests are applied to the system. By this system it is expected to develop a more realistic and effective preclinical education. Several advantages offered by the simulator include: an effective learning environment without undue fear of mistakes, facilitation of repetition, provision of opportunities to quantitatively assess student skills, rapid training environment without an instructor and lower the cost of dentist training.
18

Guidelines For Building Experimental Mobile Robots With Off-the-shelf Components

Ozkil, Gurcan Ali 01 February 2008 (has links) (PDF)
Robotics is an emerging field, and it is also affecting several other fields. Design of robotic platforms gains more importance since the focus and aim of the robotics research broadens widely and the variety of the users is significant. This work aims to present the design of a modular mobile robotic platform, which should be simple, easy to build and easy to use. The concept of modularity, usage of off-the shelf components and utilizing a PC platform, are addressed in this work. As a result of this work, a conceptual design is presented, and a prototype is built to highlight some important aspects of the conceptual design.
19

Modeling And Control Of A Hyper Redundant Manipulator

Bayram, Atilla 01 February 2010 (has links) (PDF)
The hyper redundant manipulators (HRMs) have excessively large degrees of freedom. As a special but practicable subset, the binary HRMs use binary (on-off) actuators with only two stable states such as pneumatic cylinders and solenoids. Such actuators are simple, cheap, and easy to control. Therefore, a binary HRM has been studied in this thesis. The thesis work covers the conceptual design of a spatial binary HRM together with its controlled motion simulations. The manipulator consists of many modules, each of which has the same constructive characteristics and consists of three submodules which are two cascaded variable geometry truss structures working in mutually orthogonal planes and a discrete twister. The manipulator is assumed to be powered with pneumatic on-off actuators. Because of the discrete nature of the binary actuators, a small but continuously actuated manipulator with six degrees of freedom is installed as the last module of the HRM in order to compensate the discretization errors. To solve the inverse kinematics problem of the HRM, three methods have been presented. These are the spline fitting, the extended spline fitting, and the workspace filling methods. The spline fitting method is based on forcing the spine (i.e. the center line) of the manipulator to approximate a spatial reference spline which is specified as a desired curve. In the extended spline fitting method, the result found in the first method is improved by using a genetic algorithm. In the work space filling method, the workspace of the manipulator is filled randomly with a sufficiently large finite number of discrete configurational samples. If it is desired to have concentration on a particular region of the work space, then that region is filled by using a genetic algorithm. After the filling stage, the sample closest to the desired configuration is determined by a suitable search algorithm. Finally, in order to simulate the motion of the HRM between two successive configurational steps, the equations of motions of the HRM are obtained in terms of the pressure forces generated by the binary pneumatic actuators. Then, the necessary simulations are carried out to demonstrate the performance of the HRM in some typical applications.
20

Development Of A Two-fingered And A Four-fingered Robotic Gripper

Dogan, Burak 01 May 2010 (has links) (PDF)
In this thesis study, a two-fingered gripper and a four-fingered multipurpose gripper are developed and manufactured. In addition to development of robotic hands, computer control hardware and software are also developed for computer control of both hands. The two-fingered gripper is designed for a specially defined pick and place operation. Its task is to pick a cylindrical work piece and place it in the appropriate position in a flexible manufacturing cell. Pneumatic actuator is used for power generation and mechanical links are used for power transmission. Fourfingered gripper is designed as a multipurpose gripper. The task is not predefined for this gripper, so, human hand and previous dexterous hands are taken as model during design. It consists of 3 fingers and a thumb. It has 1 degree of freedom for every finger and thumb. Pneumatic actuators are also used for this gripper. Rope and pulley system is used for the power transmission mechanism. Structures of both hands are manufactured from 5083 series aluminum. Gripping force can be controlled by the pressure regulator of the pneumatic system for both hands. Computer software is developed for the control of open and close motion of the fingers. Also, a motion control card is designed and manufactured for control of the pneumatic valves.

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