Thesis (Ph. D.)--University of Wisconsin, 1966. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliography.

Thesis (M.S.)--University of Wisconsin--Madison, 1966. / eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.

Thesis (Ph. D.)--University of Wisconsin--Madison, 1958. / Typescript. Abstracted in Dissertation abstracts, v. 19 (1959) no. 7, p. 1695-1696. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 102-103).

Thesis (D.Eng.)--Cleveland State University, 2009. / Abstract. Title from PDF t.p. (viewed on Oct. 26, 2009). Includes bibliographical references (p. 78-89). Available online via the OhioLINK ETD Center and also available in print.

Systems with delays frequently appear in engineering. The presence of delays makes system analysis and control design much more complicated. Networked control systems where the delays are often random are typical cases of such systems. For one particular category of time-delays systems, integral processes with dead time (IPDTs), the control limits that a PI controller can achieve are discussed in this thesis. These limits include the region of the control parameters to guarantee the system stability, the control parameters to achieve the given gain and/or phase margins (GPMs), the constraint on achievable gain and phase margins, the performance of set point tracking and disturbance rejection. Three types of PI controllers, namely typical PI controller, single tuning-parameter PI controller and PI controller under two-degree-of-freedom (2-DOF) structure, are studied. In control schemes of the modified Smith predictor (MSP) where the controller usually includes a distributed delay, the system implementation is not trivial because of the inherent hidden unstable poles. This thesis provides an estimation of the minimal number of implementation steps for the distributed delay in linear control laws. This is obtained by solving an inequality with respect to the number of implementation steps. A coarse estimation is given as the initial value to solve the inequality using bisection algorithms. A minimization process as well as some other techniques are also introduced to further improve the estimation. In networked control systems, the network-transmission delay and data dropout are combinedly represented by a network-induced delay. By designing a data pre­ processing mechanism, the network-induced delay can be assigned. Such delay as­ signment is applied to networked predictive control schemes, which alleviates systemstability limits on the network-induced delay. Two stability criteria are given for the closed-loop system with random network-induced delay, and a resulting implementation algorithm is also provided. The control and implementation of a magnetic levitation system over the network is studied in this thesis. Firstly, a test-rig which is suitable to implement control over a network is set up. Feedback linearization and direct local linearization methods for the nonlinear MagLev system are presented. In order to improve the control performance, a networked predictive method is employed, where the system model is identified in real-time. Local control and networked control are implemented on this test-rig, including networked predictive control. Model predictive control demonstrates a clear performance advantage over the networked control strategies which does not incorporate compensation for the network-induced delay. In order to quickly implement networked control systems (NCSs) by simulation or practical application, a MATLAB/Simulink based NCS toolbox is developed. This toolbox incorporates basic parts of a general NCS, that is, network simula­tion, network interface, plant interface and typical control schemes. With the NCS toolbox, users can focus on the study of new control schemes.

This thesis mainly focuses on two Internet based control applications. One is a networked control system (NCS) where the control loop is closed through the network. The other is the Networked Control System Laboratory (NCSLab) which is a global web based remote experimentation platform. The contribution in the first part of the thesis relates to the networked predictive control (NPC) which was first introduced by Liu et al. (2004). In this method, the controller uses the model predictive approach to predict a future control sequence and send it to the plant in a network packet. The plant side receives this packet and then determine the appropriate control signal to apply to the actuator according to the time delay measurement. This method is innovative and works well in theory, but it has two deficiencies in practical applications. The first deficiency is that it needs synchronization between the controller and plant side to measure the individual forward and feedback channel time delays and this is very hard to achieve on the Internet. In this thesis, a round-trip NPC is proposed in which the predictive calculations and signal selections are based on the round-trip delay. The measurement of the round-tip delay is achieved using the plant side clock only, so that the need for synchronization is avoided. The second deficiency is that the mathematical model has to be accurately known. Otherwise the accuracy of the predictive calculation is affected, which may result in a degraded control performance. An event-driven NPC scheme is introduced to solve this problem. In this scheme, the selection of the appropriate control signal is not based on the time delay measurement but on the previous system output. This method can compensate for the effect of model uncertainty, which has been verified by both simulations and real-time experiments. Some experiments carried out on other NPC schemes are also reported on in this thesis. They are the NPC in state-space form and nonlinear NPC. These methods expand the use of NPC methodology. The second part of the thesis describes the design and implementation of the Networked Control System Laboratory. The NCSLab is based in the University of Glamorgan but its test rigs are diversely located in four Institutions from both the UK and China. In order to manage these test rigs from different places, a four layer structure (Central Server/Regional Server/Sub-Server/Test Rig) is adopted. The four layers are integrated into one system via the Internet. In order to deliver the remote experimentation to the users, a web-based user interface is designed. It provides great flexibility to the users such as remote monitoring, remote tuning and remote control algorithms. The implementation of the user interface (UI) heavily adopts the AJAX technology, so the remote experiments can be conducted inside the web browsers without installing special plug-ins. In order to show how the NCSLab works, two examples are given in the thesis.

Intelligent gripping may be achieved through gripper design, automated part recognition, intelligent algorithm for control of the gripper, and on-line decision-making based on sensory data. A generic framework which integrates sensory data, part recognition, decision-making and gripper control to achieve intelligent gripping based on ABB industrial robot is constructed. The three-fingered gripper actuated by a linear servo actuator designed and developed in this project for precise speed and position control is capable of handling a large variety of objects. Generic algorithms for intelligent part recognition are developed. Edge vector representation is discussed. Object geometric features are extracted. Fuzzy logic is successfully utilized to enhance the intelligence of the system. The generic fuzzy logic algorithm, which may also find application in other fields, is presented. Model-based gripping planning algorithm which is capable of extracting object grasp features from its geometric features and reasoning out grasp model for objects with different geometry is proposed. Manipulator trajectory planning solves the problem of generating robot programs automatically. Object-oriented programming technique based on Visual C++ MFC is used to constitute the system software so as to ensure the compatibility, expandability and modular programming design. Hierarchical architecture for intelligent gripping is discussed, which partitions the robot’s functionalities into high-level (modeling, recognizing, planning and perception) layers, and low-level (sensing, interfacing and execute) layers. Individual system modules are integrated seamlessly to constitute the intelligent gripping system.

Made available in DSpace on 2014-12-02T11:16:56Z (GMT). No. of bitstreams: 0 Previous issue date: 2014-04-04Bitstream added on 2014-12-02T11:20:51Z : No. of bitstreams: 1 000796071.pdf: 3231946 bytes, checksum: cd5022e624fc51b6b608afccd527ebed (MD5) / Neste trabalho é proposto um modelo de injeção de potência para o controlador Generalized Unified Power Flow Controller (GUPFC) que permite representá-lo em programas de fluxo de potência e fluxo de potência ótimo. Também é proposto um modelo para a estrutura do sistema de controle do GUPFC que permite representar sua dinâmica em sistemas elétricos de potência. Todas as análises dinâmicas realizadas neste trabalho visam a estabilidade a pequenas perturbações, porém, o modelo de injeção de potência do GUPFC e o modelo de sua estrutura de controle permitem representálo também em um ambiente não linear. A partir das equações algébricas fornecidas pelo modelo de injeção de potência do GUPFC e das equações dinâmicas obtidas a partir da sua estrutura do sistema de controle, é possível analisar a influência que o controlador GUPFC causa no sistema, realizando-se inicialmente uma abordagem estática (em regime permanente), que foi realizada utilizando-se a ferramenta de fluxo de potência expandido. A ferramenta de fluxo de potência expandido trata as variáveis diferenciais como algébricas, para um dado ponto de equilíbrio, ficando o problema restrito a encontrar os zeros de um conjunto de funções não-lineares, cuja solução pode ser obtida através do método de Newton-Raphson, como em um fluxo de potência convencional. Com a solução desse fluxo de potência, pode-se incluir diretamente as correspondentes submatrizes do GUPFC no Modelo de Sensibilidade de Potência (MSP), já que este foi o modelo escolhido para representação de todos os componentes dinâmicos do sistema. Com todos os componentes modelados no MSP, foi realizada uma análise dinâmica do sistema, visando a estabilidade a pequenas perturbações. Para melhorar o desempenho dinâmico do sistema, foi essencial que controladores ESPs e POD fossem inclusos às malhas de controle dos Reguladores Automáticos ... / This thesis proposes a power injection model for the GUPFC (Generalized Power Flow Controller) which is suited for the GUPFC representation in both power flows and optimal power flows analyses. It is also proposed a model for the control system GUPFC that represents its dynamics in electric power systems. This work main aim is the small signal stability analysis. However, the power injection model of the GUPFC and the structure control model could be used in nonlinear environment. The algebraic equations provided by the power injection model of the GUPFC and the dynamical equations obtained from the control model, are used to analyze the influence of the GUPFC on the system, initially executing a static approach (in steady state) using the expanded power flow tools. The expanded power flow considers the differential variables as algebraic, at a given equilibrium point, and the problem is to find the zeros of a nonlinear function set, whose solution can be obtained by a Newton Raphson method as in a conventional power flow. From the solution of the power flow, it is possible to include directly the corresponding sub matrices of the GUPFC in to the Power Sensitive Model (PSM), which is the chosen model to represent all the dynamic components of the system. Once, every component is modeled in the PSM, a small signal stability is performed. The ESP and POD controllers are included in to the control loop of the Automatic Voltage Regulators (AVR) and the GUPFC respectively, to improve the dynamical performance of the system. To provide additional damping to the unstable or little damped modes and increase the stability limits, a Particle Swarm Optimization (PSO) technique is used to provide the parameters of the supplementary damping controller. Two objective functions are proposed to lead the problem solution to good results and then compared to well known classical techniques

Thesis (MTech (Electrical Engineering))--Peninsula Technikon, Cape Town,1996 / The Southern Nylon Spinning plant, at South African Nylon Spinners in Bellville - Cape Town - South Africa, is one of the oldest on the site and a need arose to upgrade the existing method used in speed monitoring in this particular plant. This system was unable to produce alarms on speed limits being exceeded (i.e. on under-speed or over-speed). There was no alarm logging or historical trending. Manual records on speed were either incomplete or non-existent. Thus the purpose of this study was to investigate the existing speed monitoring system and implement a suitable computerised method of speed monitoring.

An investigation is made into the approximate synthesis of optimal feedback controllers from the maximum principle necessary conditions. The overall synthesis can be separated into two phases: the computation of optimal open-loop controls (control programs) and trajectories from the necessary conditions, and the processing of this data to obtain an approximate representation of the optimal control as a state function. A particular technique for approximating the optimal feedback control from the optimal open-loop controls and trajectories is proposed and examined in Part I of the thesis. Parameters in a prechosen suboptimal controller structure are computed such that a sum of integral square deviations between the suboptimal and optimal feedback controls is minimized. The deviations are computed and summed over a certain set of trajectories which "cover" the system operating region. Experimentation with various controller structures is quite feasible since the controller parameters are computed by solving linear algebraic equations. Examples are given to illustrate the application of the technique and ways in which suitable controller structures may be found. If general purpose functions are to be used for this purpose, piecewise polynomial functions are recommended and techniques for their use are discussed. The synthesis method advocated is evaluated with respect to control sensitivity and instrumentation and compared to alternative procedures. Part II is concerned with the computation of optimal control programs, the most time consuming numerical task in the synthesis procedure. A new numerical optimization technique is presented which extends the function space Newton-Raphson method (quasilinearization) to a more general terminal condition. More significantly, a generalized Ricatti transformation is employed, and as a consequence, the integration of the unstable coupled canonical system is eliminated. Examples are given as evidence of the improved numerical qualities of the new algorithm. This method is one example of a class of algorithms, defined and developed in the thesis, called second variation methods. Some methods in this class have previously appeared in the literature but they are developed in the thesis from a unified point of view. The recognition of this class allows the relationships between the various methods to be seen more clearly as well as allowing techniques developed for use in one algorithm to be used in others. / Applied Science, Faculty of / Electrical and Computer Engineering, Department of / Graduate