Dissertations / Theses: 'Digital control systems'

1

Behzadi, M. A. "True digital control of greenhouse systems." Thesis, Lancaster University, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.236319.

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Toriumi, Fabio Yukio. "Controle digital de uma planta giroscópio." Universidade de São Paulo, 2016. http://www.teses.usp.br/teses/disponiveis/3/3139/tde-21122016-090720/.

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Esta dissertação apresenta a modelagem matemática de um giroscópio de controle de momento (CMG) e aplica técnicas de controle digital para o controle de atitude dessa planta. CMGs são atuadores importantes para o controle de atitude de corpos no espaço, tais como satélites e veículos espaciais. Desenvolve-se a modelagem da planta por meio da mecânica Lagrangiana e estudam-se técnicas específicas de controle PID (proporcional-integral-derivativo) e LQR (linear-quadratic regulator ) digitais para aplicação em sistemas com a planta nas configurações desacoplada e acopladas de fase mínima e não-mínima. Realizam-se ensaios via simulação, com o modelo não-linear da planta, bem como via experimentos práticos, com o sistema real, para validar os controladores projetados. Com isso, obtêm-se resultados positivos com ambas as técnicas estudadas, com exceção ao caso acoplado de fase não-mínima, para o qual uma das técnicas não foi capaz de controlar a atitude da planta.
This dissertation presents the mathematical modeling of a control moment gyroscope (CMG) and applies digital control techniques for its attitude control. CMGs are important actuators for bodies attitude control in the space, such as satellites and space vehicles. The system modeling is developed with the Lagrangian mechanics and a digital proportionalintegral- derivative (PID) and a digital linear-quadratic regulator (LQR) control techniques are studied and applied to a decoupled system and coupled systems with minimum and non-minimum phases. Simulation tests with the non-linear plant model and experimental tests with the real plant are done in order to validate the control techniques. Then, positive results are reached with both studied techniques, excepting in the coupled system with non-minimum phase, in which one technique was not able to control it.

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Bolton, Alan Graham. "Digital filters and cascade control compensators /." Title page, contents and abstract only, 1990. http://web4.library.adelaide.edu.au/theses/09PH/09phb694.pdf.

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Whiting, Ian Martin. "Closed loop digital control of electrohydraulic systems." Thesis, University of Bath, 1987. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.375516.

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鄧國瀚 and Kwok-hon Tang. "Digital control enhancement of triac cycloconverter systems." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 1987. http://hub.hku.hk/bib/B31231354.

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Tang, Kwok-hon. "Digital control enhancement of triac cycloconverter systems /." [Hong Kong : University of Hong Kong], 1987. http://sunzi.lib.hku.hk/hkuto/record.jsp?B12227808.

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Luo, F. L. "Digital control of power semiconductor converters." Thesis, University of Cambridge, 1986. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.383314.

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Nocetti, Demetrio Fabian Garcia. "Parallel processing in digital flight control." Thesis, Bangor University, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.278518.

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Plummer, Andrew Robert. "Digital control techniques for electro-hydraulic servosystems." Thesis, University of Bath, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.280263.

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McConnell, George. "Digital bank-to-turn control and guidance." Thesis, Queen's University Belfast, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.303013.

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Craig, Robert George Alexander. "Implementation, control and programming of digital optical systems." Thesis, Heriot-Watt University, 1991. http://hdl.handle.net/10399/879.

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Elphick, Jonathan Richard. "Fault tolerance in rotorcraft digital flight control systems." Thesis, University of York, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.296389.

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Schipman, Kurt. "Control systems and algorithms for active filters." Thesis, Staffordshire University, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.360218.

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Petropoulakis, L. "Design of digital trajectory tracking systems for robotic manipulators." Thesis, University of Salford, 1986. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.384976.

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Stroph, Ralf. "Acceptance test design for fault tolerant, digital control systems." Thesis, University of York, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.298586.

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Al-Sadigi, G. M. "Self-tuning digital controllers for servo systems." Thesis, Loughborough University, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.377008.

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Barton, Andrew Dennis. "Control of high speed chain conveyor systems." Thesis, University of Southampton, 1999. https://eprints.soton.ac.uk/421466/.

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18

Van, Papendorp J. F. "Digital control of line-interactive UPS." Thesis, Stellenbosch : University of Stellenbosch, 2011. http://hdl.handle.net/10019.1/6537.

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Thesis (MScEng (Electrical and Electronic Engineering))--University of Stellenbosch, 2011.
ENGLISH ABSTRACT: The digital control of UPS systems has been difficult in the past due to a lack of DSP technology. It was for this reason not possible to establishing the necessary control to regulate the voltages and currents of the UPS systems. Recent advances in DSP technology have however provided the means of establishing central control of the UPS system as well as incorporating more complex closed-loop control algorithms by utilising a single floating-point DSP. Closed-loop control strategies are investigated and the central control of a line-interactive UPS is established in this study. Both the status of the physical system as well as various system parameters are controlled. The system both regulates and charges the storage batteries when the main utility supply is maintained. In the event that the utility fails, the converter instantaneously changes power flow towards the load with the aim of maintaining an uninterrupted voltage supply. Several closed-loop deadbeat based control strategies are investigated for the regulation of the inductor current. A solution for the regulation of the DC-link is also developed and implemented. Furthermore, an intensive study is done on the regulation of the voltage supplied to the load in the event that the utility supply fails. The investigation is initially approached by considering classical control theory. Although these control strategies provided sufficient results, a predictive strategy that is based on the physical conditions of the switching converter is finally investigated to establish closed loop control of the output voltage. This resulted in a high-bandwidth voltage controller capable of maintaining control under a wide-array of load conditions.
AFRIKAANSE OPSOMMING: Die digitale beheer van UPS stelsels was moeilik in the verlede as gevolg van 'n gebrek aan DSP tegnologie. Dit was vir hierdie rede nie moontlik om beheer te kon bewerkstelling ten einde die spannings and strome in the UPS stelsels te kon reguleer nie. Onlangse vordering in DSP tegnologie het egter dit moontlik gemaak om sentrale beheer van die UPS stelsel te bewerkstellig sowel as om meer komplekse geslote lus beheer algoritmes te inkorporeer met behulp van 'n enkele DSP. Geslote lus beheer strategiëe word ondersoek en die sentrale beheer van die line-interaktiewe UPS word bewerkstellig in hierdie studie. Beide die huidige toestand van die fisiese stelsel sowel as die verskeie parameters word beheer. Die stelsel beide laai en reguleer die batterye terwyl die hooftoevoer onderhou word. In die geval dat die hooftoevoer faal, word die omsetter se rigting van drywingsvloei verander om die las te voorsien van 'n ononderbroke spannings toevoer. Verskeie geslote-lus “deadbeat” beheer strategiëe word ondersoek vir die regulasie van die induktor stroom. 'n Oplossing vir die regulasie van die GS-koppervlak word ook ontwikkel en geïmplementeer. Verder word 'n intensiewe studie gedoen op regulasie van die spanning wat aan die las gevoer word in die geval dat die hooftoevoer faal. Hierdie ondersoek word aanvanklik benader deur klassieke beheer teorie te bestudeer. Alhoewel hierdie beheer strategiëe voldoene resultate gebied het, was 'n voorspel beheerstrategie gebaseer op die fisiese toestand van die omsetter finaal ondersoek. Die resultaat is 'n hoë-bandwydte spannings beheerder wat daartoe instaat is om beheer te handhaaf onder 'n verskeidenheid van lastoestande.

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Wang, Xuan. "Verification of digital controller implementations /." Diss., CLICK HERE for online access, 2005. http://contentdm.lib.byu.edu/ETD/image/etd1073.pdf.

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Gawlik, Aaron John. "Applied high resolution digital control for universal precision systems." Thesis, Massachusetts Institute of Technology, 2008. http://hdl.handle.net/1721.1/44886.

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Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2008.
Includes bibliographical references (p. 223-225).
This thesis describes the design and characterization of a high-resolution analog interface for dSPACE digital control systems and a high-resolution, high-speed data acquisition and control system. These designs are intended to enable higher precision digital control than currently available. The dSPACE system was previously designed within the PMC Lab and includes higher resolution A/D and D/A interfaces than natively available. Characterization on the custom A/D channel demonstrates 20.1 effective bits, or a 121 dB dynamic range, and the custom D/A channel demonstrates 15.1 effective bits, or a 91 dB dynamic range. This compares to a 15.7 effective bits on the A/D dSPACE channel and 12.3 effective bits on the D/A dSPACE channel. The increased resolution is attained by higher performance hardware and oversampling and averaging the A/D channel. The sampling rate is limited to 8 kHz. The high-resolution, high-speed data acquisition and control system can sample two A/D channels at 2.5 MHz and display/save an acquired one second burst. The A/D channel is characterized at 109 dB dynamic range with a grounded input and 96 dB dynamic range, or 0.74 nm RMS over a 50 [mu]m range, with a fixtured capacitive probe. Acquisition at 2.5 MHz and closed-loop control at 625 kHz sampling rate is implemented on a National Instruments FPGA. The A/D circuit was designed and built on a custom printed circuit board around the commercially available AD7760 sigma-delta converter from Analog Devices and includes fully differential ±10 V inputs, a dedicated microcontroller to provide an initialization sequence, and digital galvanic isolation. LabVIEW FPGA code demonstrates arbitrary transfer function control implementation.
(cont.) The digital platform is applied to a 1-DOF positioner to demonstrate 0.10 nm RMS control over a 10 [mu]m mechanical range when filtered to the 1.5 kHz closed-loop bandwidth, which is limited by the A/D converter architecture propagation delay.
by Aaron John Gawlik.
S.M.

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21

Celanovic, Ivan. "A Distributed Digital Control Architecture for Power Electronics Systems." Thesis, Virginia Tech, 2000. http://hdl.handle.net/10919/34998.

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This thesis proposes a novel approach to power electronics system design that is based on the open-architecture distributed digital controller and modular power electronics building blocks (PEBBs). The proposed distributed digital controller partitions the controller in three levels of control authority. The power stage controller, designated as hardware manager, is responsible for low-level hardware oriented tasks; the high level controller, designated as applications manager, performs higher-level application-oriented tasks; and the system level controller handles system control and monitoring functions. Communications between the hardware-oriented controller and the higher-level controller are implemented with the previously proposed 125 Mbits/sec daisy-chained fiber optic communication protocol. Real-time control and status data are communicated by means of communication protocol. The distributed controller on the power converter level makes the system open, flexible and simple to use. Furthermore, this work gives an overview and comparison of current state-of-the-art communication protocols for real-time control applications with emphasis on industrial automation and motion control. All of the studied protocols have been considered as local area networks (LAN) for system-level control in power converter systems. The most promising solution has been chosen for the system level communication protocol. This thesis also provides the details of design and implementation of the distributed controller. The design of both the hardware and software components are explained. A 100 kVA three-phase voltage source inverter (VSI) prototype was built and tested using the distributed controller approach to demonstrate the feasibility of the proposed concept.
Master of Science

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22

Hicks, Dawn L. "Optimal design of digital model-following systems." Thesis, University of Salford, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.284423.

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McArdle, M. G. "A digital controller for the small salient-pole alternator." Thesis, Queen's University Belfast, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.269154.

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Merzougui, T. "Design of digital controllers for irregular linear multivariable plants." Thesis, University of Salford, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.308206.

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Iyer, Gopal Balakrishnan. "Digital communication and control circuits for 60ghz fully integrated CMOS digital radio." Thesis, Georgia Institute of Technology, 2010. http://hdl.handle.net/1853/39589.

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Emerging "bandwidth hungry" applications such as high definition video distribution and ultra fast multimedia side-loading have extended the need for multi-gigabit wireless solutions beyond the reach of conventional WLAN technology or even more recently emerging UWB and MIMO systems. The availability of 7GHz of unlicensed bandwidth in the 60GHz spectrum, represents a unique opportunity to address such data-throughput requirements. The 60GHz Integrated CMOS digital radio chipset comprises of PHY and MAC layers, RF transceiver, High-Speed Digital Interface and an underlying Serial Communication Fabric. To have a complete communication solution compliant with the latest ECMA-369, ISO/DIS 13156 and IEEE 802.15.3c standards, we build a million gate digital implementation of MAC and PHY. The Serial Peripheral Interface (SPI) serves as the bridge between the higher layers in the communication stack (PAL-MAC) and the lower layers like PHY-RF Front End. The MAC module can setup the communication link on the fly by tuning parameters such as operating channel, channel bonding and bandwidth, data rates, error correction mechanisms, handshaking mechanisms, etc, by using the SPI to communicate with internal components. The SPI interface plays a crucial rule in not only this, but also during the testing and debug phase. Operation of each of the RF modules is monitored through the serial interface using local SPI slaves which are hooked up to the 4-wire serial bus running all through the chip. The SPI host controller emulates an embedded protocol analyzer. For calibration and fine tuning purposes, digital settings can also be loaded onto these modules through the SPI interface. R-2R DACs are used to convert these commands into analog voltages which then provide a tunable bias to the RF and mixed-signal modules. Other key functions of this serial communication and control interface are: Initialization of all of the RF and mixed signal modules, DC calibration of data converter, PLL and other mixed-signal modules, data acquisition, parametric tuning for digital modules such as linear equalizer, Gain Control loops (AGC, VGA), etc. Ultra high speed digital Input-Output buffers are used to provide an external data interface to the radio chipset. These high speed I/Os are also used in the gbps (gigabit-per-second) link for data transfer between the RF transceiver chip and the PHY-MAC baseband chip. The IOs are expected to comply with different signaling standards such as LVDS, SLVS200, SLVS400, etc. A robust system involves a meticulous pad ring design with proper power domains and power cuts. Full-chip integration of the digital PHY, MAC, peripheral logic and IO ring is done in a semi-custom fashion.

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Clark, Kenneth A. "Modeling single-event transients in complex digital systems." Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 2002. http://library.nps.navy.mil/uhtbin/hyperion-image/02Jun%5FClark%5FKenneth%5Fphd.pdf.

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Bainbridge, Christopher James. "Digital control networks for virtual creatures." Thesis, University of Edinburgh, 2010. http://hdl.handle.net/1842/4812.

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Robot control systems evolved with genetic algorithms traditionally take the form of floating-point neural network models. This thesis proposes that digital control systems, such as quantised neural networks and logical networks, may also be used for the task of robot control. The inspiration for this is the observation that the dynamics of discrete networks may contain cyclic attractors which generate rhythmic behaviour, and that rhythmic behaviour underlies the central pattern generators which drive lowlevel motor activity in the biological world. To investigate this a series of experiments were carried out in a simulated physically realistic 3D world. The performance of evolved controllers was evaluated on two well known control tasks—pole balancing, and locomotion of evolved morphologies. The performance of evolved digital controllers was compared to evolved floating-point neural networks. The results show that the digital implementations are competitive with floating-point designs on both of the benchmark problems. In addition, the first reported evolution from scratch of a biped walker is presented, demonstrating that when all parameters are left open to evolutionary optimisation complex behaviour can result from simple components.

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Grimes, Todd S. "Adaptive Power Analog-to-Digital Interface for Digital Systems." Wright State University / OhioLINK, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=wright1483366560887816.

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Wong, Timothy M. H. "Digital implementation of a feedback controller for scanning probe microscopy." Thesis, University of Cambridge, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.240094.

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Al-Fakhri, Loui Ali Hussain. "ADPCM distortion of digital data transmitted at 9.6 kbit/s." Thesis, Loughborough University, 1989. https://dspace.lboro.ac.uk/2134/10337.

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This work is concerned with the effects of Adaptive Differential Pulse Code Modulation (ADPCM) on digital data transmitted at 9.6 kbit/s. To facilitate the study, a system model was developed. The model simulates the complete communication system, including true bandpass simulation of the modulation and demodulation processes. The model was used to observe the behaviour of the ADPCM link and the distortion it produces when digital data are transmitted at 9.6 kbit/s. The observations were employed to devise two ADPCM distortion cancellation schemes. Scheme-1 employs a look-up-table. The cancellation is here determined by the last two detected symbols and the sampling phase. Scheme-2 operates without a memory. The cancellation is achieved by signal level compensation. The performances of these schemes, operating with different detectors, are compared with the performance of the system when a non-linear equaliser is applied to the digital data in the absence of ADPCM distortion. Tests were conducted using two channels: CH-1 which introduces mild distortion into the transmitted digital signal, and CH-2 which introduces significant distortion. The detectors used in the tests are a linear equaliser, a non-linear equaliser and a near-maximum-likelihood detector. Scheme-2, which is the simpler of the two schemes, when used with the near-maximum-likelihood detector has a significantly better performance than the other systems tested.

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Huynh, Nguyen. "Digital control and monitoring methods for nonlinear processes." Link to electronic thesis, 2006. http://www.wpi.edu/Pubs/ETD/Available/etd-100906-083012/.

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Dissertation (Ph.D.)--Worcester Polytechnic Institute.
Keywords: Parametric optimization; nonlinear dynamics; functional equations; chemical reaction system dynamics; time scale multiplicity; robust control; nonlinear observers; invariant manifold; process monitoring; Lyapunov stability. Includes bibliographical references (leaves 92-98).

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Broos, Elizabeth. "Information, communication and technological competencies in a digital working environment a case study in the Netherlands Defence Organization /." Pretoria : [s.n.], 2007. http://upetd.up.ac.za/thesis/available/etd-06182008-115804/.

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Quibell, Jason. "Digital control of a Class-D Audio Amplifier." Thesis, Cape Peninsula University of Technology, 2011. http://hdl.handle.net/20.500.11838/1116.

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Thesis (MTech (Electrical Engineering))--Cape Peninsula University of Technology, 2011
Modern technologies have led to extensive digital music reproduction and distribution. It is fitting then that digital audio be amplified directly from its source rather than being converted to an analogue waveform before amplification. The benefits of using a digital controller for audio processing include being able to easily reconfigure the system and to add additional functions at a later stage.Digital audio is primarily stored as Pulse Code Modulation (PCM) while Pulse Width Modulation (PWM) is the most popular scheme used to drive a class-D amplifier. The class-D amplifier is selected in many applications due to its very high energy efficiency. Conventional PCM to PWM conversion is inherently nonlinear. Various interpolation schemes are presented in this research project which help to address the nonlinearity.Digitally generated PWM has a limited resolution which is constrained by the system clock. This thesis presents noise shaping techniques which increase the effective resolution of the PWM process without having to use an excessively high system clock. Noise shaping allows a low resolution modulator to be used to reproduce high resolution audio.

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Vargas, Henik Vladimir. "Robust damping of a directional microphone using digital feedback." Diss., Online access via UMI:, 2008.

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Thesis (M.S.)--State University of New York at Binghamton, Thomas J. Watson School of Engineering and Applied Science, Department of Electrical and Computer Engineering, 2008.
Includes bibliographical references.

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Kozak, Kristopher Charles. "Dynamic analysis of parallel manipulators and digital inut shaper computation using linear optimization." Thesis, Georgia Institute of Technology, 2001. http://hdl.handle.net/1853/16378.

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Ward, Ronald P. "Software Considerations in the Control of Digital Communications Switching Systems." International Foundation for Telemetering, 1992. http://hdl.handle.net/10150/611926.

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International Telemetering Conference Proceedings / October 26-29, 1992 / Town and Country Hotel and Convention Center, San Diego, California
Today's complex implementations of integrated packet and circuit switched digital communications networks demand that the software used for controlling these systems be robust, fault tolerant, and capable of runtime recovery from all but the most severe of operational errors. The typical modern switched communications system includes the use of multiple circuit switches, each with potentially thousands of end-user interfaces. Further, these switches are often inter-connected to each other via high-capacity trunks. A single connection between two end-user interfaces often traverses a number of intermediate circuit switches in order to effect the end-to-end communications desired. In this complex, distributed environment, the establishment and dissolution of end-to-end user connections involve far more than simple binary connection states indicating the existence, or non-existence, of a link. More commonly, a single end-to-end connection requires multiple node links across multiple, heterogeneous interfaces. The command and control software used to establish, monitor, and dissolve these connections must be capable of dealing with errors which arise at any node along the way in a consistent and reliable manner. Most critically, the system software must be capable of maintaining an accurate, multi-level mapping of distributed resources' availability, allocation, and status. Further, the software must have the capability of "healing itself" during operational run-time when it can, and of accurately reporting the nature of inconsistencies caused by anomalous events that cannot be fixed on the fly. The Edwards Digital Switch (EDS), developed by CSTI, provides a case study of possible solutions, and potential pitfalls, that can arise in the design, development, and implementation of the controlling software in today's dynamic, distributed communications' system architectures.

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Abbassi, Hadj Ahmed. "Control of an electromagnetic suspension system using TMS 32020 digital signal processor." Thesis, University of Reading, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.303466.

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Liao, Hao Hsiang. "Digital Timing Generator for Control of Plasma Discharges." Thesis, Linköpings universitet, Elektroniska Kretsar och System, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-161090.

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This thesis report presents a new design of a synchronization unit for high power impulse magnetron sputtering (HiPIMS) applications used for depositing thin films. The proposed system is composed of two major hardware parts: a microcontroller unit (MCU) and a field-programmable gate array (FPGA). The control range of the new system is increased by at least ten times compared to existing synchronization unit designed by Ionautics AB.In order to verify the system and benchmark its innovations, several batches of the thin film have been deposited using the new technology. It is shown that HiPIMS with synchronized pulsed substrate bias can effectively improve coating performance. Pulsed substrate bias with user-defined pulse width and delay time is possible to use in the new control mode proposed by this master thesis work; Bias mode. As a result, this master thesis work enables users to flexibly control the HiPIMS processes.

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Abidin, Zainal. "Design of digital high-accuracy trajectory tracking systems for multivariable plants." Thesis, University of Salford, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.304589.

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Borairi, M. "Genetic design of tunable digital set-point tracking controllers for linear multivariable plants." Thesis, University of Salford, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.262674.

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Carter, Clinton E. "Susceptibility of a digital turbine control system to IEEE 802.11 compliant emissions." Thesis, University of North Texas, 2003. https://digital.library.unt.edu/ark:/67531/metadc4433/.

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Within the nuclear industry, there have been numerous instances of radio transmissions interfering with sensitive plant equipment. Instances documented vary from minor instrument fluctuations to major plant transients including reactor trips. With the nuclear power industry moving toward digital technologies for control and reactor protection systems, concern exists regarding their potential susceptibility to contemporary wireless telecommunications technologies. This study evaluates the susceptibility of Comanche Peak's planned turbine controls upgrade to IEEE 802.11 compliant wireless radio emissions. The study includes a review of previous research, industry emissions standards, and technical overview of the various IEEE 802.11 protocols and details the testing methodology utilized to evaluate the digital control system. The results of this study concluded that the subject digital control system was unaffected by IEEE 802.11 compliant emissions even when the transmitter was in direct contact with sensitive components.

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Chrysanthou, A. "Digital control of linear multivariable plants with input and output time delays." Thesis, University of Salford, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.353969.

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Maggard, William P. "Adaptive control of flexible systems using self-tuning digital notch filters." Ohio : Ohio University, 1987. http://www.ohiolink.edu/etd/view.cgi?ohiou1183056097.

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Hossain, Mohammed Alamgir. "Digital signal processing and parallel processing for real-time adaptive noise and vibration control." Thesis, University of Sheffield, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.484164.

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Oliver, Michael Andrew. "Theory and application of error analysis for improving the performance of practical digital controllers." Thesis, Loughborough University, 1997. https://dspace.lboro.ac.uk/2134/13882.

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The thesis begins with an overview of the four types of error that are generated in digital filters which arise from two sources. The first source is the quantisation of time through the sampling process which gives rise to the first error type - algorithmic error. The second source of error is the quantisation of amplitude due to finite wordlength effects. Coefficient representation error (coefficient error), ADC quantisation error (ADC error) and multiple-word truncation error (truncation error) are all effects of amplitude quantisation. The shift operator commonly used in digital filters is prone to sensitivity problems especially at high sampling rates. Alternative filter operators are reviewed and advantages and disadvantages of their use are identified in enhancing the performance of digital filters. The measurement of algorithmic error and coefficient error can be carried out deterrninistically whilst ADC error and truncation error need to be treated stochastically. The thesis presents a technique to separate the deterministic error and the stochastic error in a composite output signal from a digital filter that is implemented using a high-Ievellangnage with floating-point arithmetic. This technique represents a method for validating the error analysis techniques. The error analyses presented in the thesis are used as tools to improve the performance of emulated digital filters. Each different error form varies in an individual manner with respect to changes in the sampling period. By careful selection of a sampling rate the filter performance can be improved by ensuring that the magnitudes of all the error forms are consistent with each other. Similar techniques can be used to improve the performance of digital compensators in c1osedloop control systems. Careful consideration of the duration of the sampling interval needs to be observed to ensure that the stability of the closed-loop system is adequate. This method of determining the controller parameters is used to exploit the digital control hardware to its fullest potential, and is automated in software; details are described in the thesis.

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Wang, Zhongli. "New methods for the direct digital control of discrete-time systems." Thesis, Lancaster University, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.383582.

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Dworak, Joseph A. (Joseph Alan). "Digital control of the hydraulic actuators of an adaptive suspension vehicle /." The Ohio State University, 1985. http://rave.ohiolink.edu/etdc/view?acc_num=osu1487259125220105.

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Gee, Alan David. "Digital automatic flight control systems for advanced rotorcraft : an analysis framework." Thesis, University of York, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.341474.

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Pitsillides, Andreas, and Andreas Pitsillides@ucy ac cy. "Control structures and techniques for broadband-ISDN communication systems." Swinburne University of Technology, 1993. http://adt.lib.swin.edu.au./public/adt-VSWT20060321.132650.

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A structured organisation of tasks, possibly hierarchical, is necessary in a BISDN network due to the complexity of the system, its large dimension and its physical distribution in space. Feedback (possibly supplemented by feedforward) control has an essential role in the effective and efficient control of BISDN. Additionally, due to the nonstationarity of the network and its complexity, a number of different (dynamic) modelling techniques are required at each level of the hierarchy. Also, to increase the efficiency of the network and allow flexibility in the control actions (by extending the control horizon) the (dynamic) tradeoff between service-rate, buffer-space, cell-delay and cell-loss must be exploited. In this thesis we take account of the above and solve three essential control problems, required for the effective control of BISDN. These solutions are suitable for both stationary and nonstationary conditions. Also, they are suitable for implementation in a decentralised coordinated form, that can form a part of a hierarchical organisation of control tasks. Thus, the control schemes aim for global solutions, yet they are not limited by the propagation delay, which can be high in comparison to the dynamics of the controlled events. Specifically, novel control approaches to the problems of Connection Admission Control (CAC), flow control and service-rate control are developed. We make use of adaptive feedback and adaptive feedforward control methodologies to solve the combined CAC and flow control problem. Using a novel control concept, based on only two groups of traffic (the controllable and uncontrollable group) we formulate a problem aimed at high (unity) utilisation of resources while maintaining quality of service at prescribed levels. Using certain assumptions we have proven that in the long term the regulator is stable and that it converges to zero regulation error. Bounds on operating conditions are also derived, and using simulation we show that high utilisation can be achieved as suggested by the theory, together with robustness for unforeseen traffic connections and disconnections. Even with such a high efficiency and strong properties on the quality of service provided, the only traffic descriptor required from the user is that of the peak rate of the uncontrollable traffic. A novel scheme for the dynamic control of service-rate is formulated, using feedback from the network queues. We use a unified dynamic fluid flow equation to describe the virtual path (VP) and hence formulate two illustrative examples for the control of service-rate (at the VP level). One is a nonlinear optimal multilevel implementation, that features a coordinated decentralised solution. The other is a single level implementation that turns out to be computationally complex. Therefore, for the single level implementation the costate equilibrium solution is also derived. For the optimal policies derived, we discuss their implementation complexity and provide implementable solutions. Their performance is evaluated using simulation. Additionally, using an ad hoc approach we have extended previous published works on the decentralised coordinated control of large scale nonlinear systems to also deal with time-delayed systems.

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Gurrie, Thomas M. "The application of system modelling to digital electronic systems for active control of acoustic noise." Thesis, Royal Holloway, University of London, 1988. http://repository.royalholloway.ac.uk/items/57091fab-773a-4d31-b806-77ba916cb6f9/1/.

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Active noise control (ANC) is concerned with achieving some degree of cancellation between unwanted acoustic noise and the output from one or more actively controlled secondary sources. The minimum configuration for an A.N.C. system is a detecting microphone to detect the unwanted acoustic noise and a single loudspeaker to act as a secondary source. The basic problem is to specify the electronic system needed between the detecting microphone and the loudspeaker to achieve cancellation. The system has an inherent feedback pathbetween the loudspeaker and the detecting microphone that may cause instability. The system described in this thesis uses the principle of parallel feedback to ensure system stability. The basic idea of this is to use a second electronic system in a feedback path parallel to the electroacoustic feedback path to, in effect, remove this feedback. Incorporating both this feedback modelling and the appropriate forward transfer function between thedetecting microphone and the loudspeaker should produce a practical stable working system. This thesis considers implementation of these two electronic systems as sampled data systems employing finite impulse response (FIR) filters. Measurements on an experimental duct are used as input data for the study of system performance, this data being analysed using aleast squares approach to find best fit. FIR filters. The system is assessed in terms of the lengths of FIR filters required in the feedforward and feedback paths to achieve satisfactory operation, i.e. that the system produce a significant level of attenuation and be stable. The predicted level of performance of the ANC system indicates that the use of two independent FIR filters to model the feedforward and feedback paths produces a stable working system, capable of producing a significant level of attenuation over a broad frequency range. However, the length of FIR filter needed in each path has to be long in order to achieve a satisfactory level of performance.

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Dissertations / Theses on the topic 'Digital control systems'

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