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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.
41

Development Of A Miniaturized Automated Production Control System

Korkmaz, Ozgur 01 January 2012 (has links) (PDF)
In this thesis a custom embedded system and control software developed for an Automated Storage and Retrieval System (AS/RS) which is based on the Computer Integrated Manufacturing Laboratory (CIMLAB) located in the Department of Mechanical Engineering, Middle East Technical University. Primary objective of this study is AS/RSs related control rules can be applicable to the current physical system. The secondary objective is determined as developing the control system in a flexible way that allows adding new equipments to the system and configuring parts of the system. Two types of control board are manufactured and also boards&rsquo / firmware and computer software are developed. These two boards communicate with computer one at a time. Some AS/RS related control rules are implemented at the control software. According to these rules the control software assigns tasks to the related board. Also the control software records necessary information in order to measure the performance of the AS/RS. Several control rules as storage assignment, dwell point and sequencing of storage and retrieval order rules are applicable to the AS/RS without need for low level programming. Because of the physical limitation, batching rules cannot be applied to the current system. Also a graphical user interface is developed for using the system easily and observing the real time status of the system equipments. Two experiments are designed and run in order to show flexibility of the control system. Different control rules applied to each of the experiment. Experiment results put forth the control system was quite successful in meeting the objectives.
42

Dynamic Stability Analysis Of Modular, Self-reconfigurable Robotic Systems

Boke, Tevfik Ali 01 May 2005 (has links) (PDF)
In this study, an efficient algorithm has been developed for the dynamic stability analysis of self-reconfigurable, modular robots. Such an algorithm is essential for the motion planning of self-reconfigurable robotic systems. The building block of the algorithm is the determination of the stability of a rigid body in contact with the ground when there exists Coulomb friction between the two bodies. This problem is linearized by approximating the friction cone with a pyramid and then solved, efficiently, using linear programming. The effects of changing the number of faces of the pyramid and the number of contact points are investigated. A novel definition of stability, called percentage stability, is introduced to counteract the adverse effects of the static indeterminacy problem between two contacting bodies. The algorithm developed for the dynamic stability analysis, is illustrated via various case studies using the recently introduced self-reconfigurable robotic system, called I-Cubes.
43

Performance Improvement Of A 3d Reconstruction Algorithm Using Single Camera Images

Kilic, Varlik 01 July 2005 (has links) (PDF)
In this study, it is aimed to improve a set of image processing techniques used in a previously developed method for reconstructing 3D parameters of a secondary passive target using single camera images. This 3D reconstruction method was developed and implemented on a setup consisting of a digital camera, a computer, and a positioning unit. Some automatic target recognition techniques were also included in the method. The passive secondary target used is a circle with two internal spots. In order to achieve a real time target detection, the existing binarization, edge detection, and ellipse detection algorithms are debugged, modified, or replaced to increase the speed, to eliminate the run time errors, and to become compatible for target tracking. The overall speed of 20 Hz is achieved for 640x480 pixel resolution 8 bit grayscale images on a 2.8 GHz computer A novel target tracking method with various tracking strategies is introduced to reduce the search area for target detection and to achieve a detection and reconstruction speed at the maximum frame rate of the hardware. Based on the previously suggested lens distortion model, distortion measurement, distortion parameters determination, and distortion correction methods for both radial and tangential distortions are developed. By the implementation of this distortion correction method, the accuracy of the 3D reconstruction method is enhanced. The overall 3D reconstruction method is implemented in an integrated software and hardware environment as a combination of the methods with the best performance among their alternatives. This autonomous and real time system is able to detect the secondary passive target and reconstruct its 3D configuration parameters at a rate of 25 Hz. Even for extreme conditions, in which it is difficult or impossible to detect the target, no runtime failures are observed.
44

Improving Performance Of A Remote Robotic Teleoperation Over The Internet

Arslan, Mehmet Selcuk 01 August 2005 (has links) (PDF)
In this thesis study, it is aimed to improve the performance of an Internet-based teleoperation system enabling the remote operation of a 6 DOF industrial robot. In order to improve the safety and efficiency of the teleoperation, stability and synchronization (hand-eye coordination) are considered. The selected communication medium between the human operator and remote robot is the Internet. The variable time delays and nondeterministic characteristics of the Internet may lead to instability of the teleoperation system. Considering the disturbing effects of the Internet onto the transmission, an event-based control approach is used in order to improve the stability of the teleoperation system. Besides, a visual feedback system is developed and a force-feedback mouse is designed in order to improve synchronization between the human operator and robot during the command generation according to the feedback obtained from the control system. A client-server software application is developed to interface the human operator with remote environment. It is observed that, using the event-based control approach in the operation makes the teleoperation stable and improves the synchronization ability. Implementation of visual feedback and force-feedback mouse to the teleoperation system improves the human operator&rsquo / s ability to perform remote operation.
45

Electronic Packaging And Environmental Test And Analysis Of An Emi Shielded Electronic Unit For Naval Platform

Devellioglu, Yucel 01 April 2008 (has links) (PDF)
The scope of this thesis is the design and verification of an electronic packaging of a device which is a subunit of a network system that is designed for combat communication in sheltering ship. According to the project requirements this device is subjected to some environmental and electromagnetic interference tests. This thesis includes design and manufacturing steps as well as vibration, shock and thermal analyses. Electromagnetic interference is examined through the design procedure and total shielding effectiveness of the device is calculated after the applications of some electromagnetic interference precautions which are given in details.
46

Design And Analysis Of A Linear Shape Memory Alloy Actuator

Soylemez, Burcu 01 January 2009 (has links) (PDF)
Shape memory alloys are new, functional materials used in actuator applications with their high power to weight ratio. The high strength or displacement usage of shape memory alloys makes them suitable for direct drive applications, which eliminate use of power transmission elements. The aim of this research is to develop the methodology and the necessary tools to design and produce linear shape memory alloy actuators to be used in missile systems, space applications, and test equipments. In this study, the test apparatus designed and built to characterize shape memory alloy thin wires is described, and then the characterization tests, modeling and control studies performed on a wire are explained. In the control studies, displacement control through strain, resistance and power feedback is investigated and different control strategies (proportional-integral, proportional-integral with feedforward loop, and neural network) are employed. The results of the characterization tests, simulations and experiments are all presented in graphical and tabular form. From the results it is concluded that through careful characterization, the behavior of SMA wire can be closely approximated through models which can be used effectively to test various control strategies in simulations. Also, satisfactory position control of SMA wires can be achieved through both classical and NN control strategies by using appropriate feedback variables and power is found to be a viable feedback variable. Lastly, a linear SMA wire actuator is designed as a case study. The actuator prototype is produced, suitable control strategies are applied and actuator is experimented to validate the theoretical assumptions. The actuator developed through this work is a technology demonstration and shows that shape memory alloy elements can be utilized in several defense and space applications contracted to T&Uuml / BiTAK-SAGE as well as certification test equipments. The development of shape memory alloy actuators that can be used in defense and later in aeronautical/space applications is a critical research and development project for national defense industry.

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