The use of knowledge-based systems to aid in the diagnosis of faults in physical devices has grown considerably since their introduction during the 1970s. The majority of the early knowledge-based systems incorporated shallow knowledge, which sought to define simple cause and effect relationships between a symptom and a fault, that could be encoded as a set of rules. Though such systems enjoyed much success, it was recognised that they suffered from a number of inherent limitations such as inflexibility, inadequate explanation, and difficulties of knowledge elicitation. Many of these limitations can be overcome by developing knowledge-based systems which contain deeper knowledge about the device being diagnosed. Such systems, now generally referred to as model-based systems, have shown much promise, but there has been little evidence to suggest that they have successfully made the transition from the research centre to the workplace. This thesis argues that knowledge-based systems are an appropriate tool for the diagnosis of faults in complex devices, and that both deep and shallow knowledge have their part to play in this process. More specifically this thesis demonstrates how a wide-ranging knowledge-based system for quality assurance, based upon shallow knowledge, can be developed, and implemented. The resultant system, named DIPLOMA, not only diagnoses faults, but additionally provides advice and guidance on the assembly, disassembly, testing, inspection and repair of a highly complex hydro-mechanical device. Additionally it is shown that a highly innovative modelbased system, named MIDAS, can be used to contribute to the provision of diagnostic, explanatory and training facilities for the same hydro-mechanical device. The methods of designing, coding, implementing and evaluating both systems are explored in detail. The successful implementation and evaluation of the DIPLOMA and MIDAS systems has shown that knowledge-based systems are an appropriate tool for the diagnosis of faults in complex hydro-mechanical devices, and that they make a beneficial contribution to the business performance of the host organisation. Furthermore, it has been demonstrated that the most effective and comprehensive knowledge-based approach to fault diagnosis is one which incorporates both deep and shallow knowledge, so that the distinctive advantages of each can be realised in a single application. Finally, the research has provided evidence that the model-based approach to diagnosis is highly flexible, and may, therefore, be an appropriate technique for a wide range of industrial applications.

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.

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.

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.

The use of knowledge-based systems to aid in the diagnosis of faults in physical devices has grown considerably since their introduction during the 1970s. The majority of the early knowledge-based systems incorporated shallow knowledge, which sought to define simple cause and effect relationships between a symptom and a fault, that could be encoded as a set of rules. Though such systems enjoyed much success, it was recognised that they suffered from a number of inherent limitations such as inflexibility, inadequate explanation, and difficulties of knowledge elicitation. Many of these limitations can be overcome by developing knowledge-based systems which contain deeper knowledge about the device being diagnosed. Such systems, now generally referred to as model-based systems, have shown much promise, but there has been little evidence to suggest that they have successfully made the transition from the research centre to the workplace. This thesis argues that knowledge-based systems are an appropriate tool for the diagnosis of faults in complex devices, and that both deep and shallow knowledge have their part to play in this process. More specifically this thesis demonstrates how a wide-ranging knowledge-based system for quality assurance, based upon shallow knowledge, can be developed, and implemented. The resultant system, named DIPLOMA, not only diagnoses faults, but additionally provides advice and guidance on the assembly, disassembly, testing, inspection and repair of a highly complex hydro-mechanical device. Additionally it is shown that a highly innovative modelbased system, named MIDAS, can be used to contribute to the provision of diagnostic, explanatory and training facilities for the same hydro-mechanical device. The methods of designing, coding, implementing and evaluating both systems are explored in detail. The successful implementation and evaluation of the DIPLOMA and MIDAS systems has shown that knowledge-based systems are an appropriate tool for the diagnosis of faults in complex hydro-mechanical devices, and that they make a beneficial contribution to the business performance of the host organisation. Furthermore, it has been demonstrated that the most effective and comprehensive knowledge-based approach to fault diagnosis is one which incorporates both deep and shallow knowledge, so that the distinctive advantages of each can be realised in a single application. Finally, the research has provided evidence that the model-based approach to diagnosis is highly flexible, and may, therefore, be an appropriate technique for a wide range of industrial applications. / Science and Engineering Research Council, and Alvey Directorate

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.

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.

The continuously increasing demand for clean renewable energy has rekindled interest in multi-terminal high voltage direct current (HVDC) grids. Although such grids have several advantages and a great potential, their materialization has been thwarted due to the absence of HVDC breakers. In comparison with traditional alternating current (AC) breakers, they should operate and interrupt fault currents in a time frame of a few milliseconds. The aim of this thesis is focused on the design of ultra-fast electro-mechanical actuator systems suitable for such HVDC breakers.Initially, holistic multi-physics and hybrid models with different levels of complexity and computation time were developed to simulate the entire switch. These models were validated by laboratory experiments. Following a generalized analysis, in depth investigations involving simulations complemented with experiments were carried out on two of the sub-components of the switch: the ultra-fast actuator and the damper. The actuator efficiency, final speed, peak current, and maximum force were explored for different design data.The results show that models with different levels of complexity should be used to model the entire switch based on the magnitude of the impulsive forces. Deformations in the form of bending or elongation may deteriorate the efficiency of the actuator losing as much as 35%. If that cannot be avoided, then the developed first order hybrid model should be used since it can simulate the behavior of the mechanical switch with a very good accuracy. Otherwise, a model comprising of an electric circuit coupled to an electromagnetic FEM model with a simple mechanics model, is sufficient.It has been shown that using a housing made of magnetic material such as Permedyn, can boost the efficiency of an actuator by as much as 80%. In light of further optimizing the ultra-fast actuator, a robust optimization algorithm was developed and parallelized. In total, 20520 FEM models were computed successfully for a total simulation time of 7 weeks. One output from this optimization was that a capacitance of 2 mF, a charging voltage of 1100 V and 40 turns yields the highest efficiency (15%) if the desired velocity is between 10 m/s and 12 m/s.The performed studies on the passive magnetic damper showed that the Halbach arrangement gives a damping force that is two and a half times larger than oppositely oriented axially magnetized magnets. Furthermore, the 2D optimization model showed that a copper thickness of 1.5 mm and an iron tube that is 2 mm thick is the optimum damper configuration. / <p>QC 20150422</p>