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Full-Text Articles in Electrical and Computer Engineering

A Classification Of Techniques For The Compensation Of Time Delayed Processes. Part 1: Parameter Optimised Controllers, Aidan O'Dwyer, John Ringwood Jan 1999

A Classification Of Techniques For The Compensation Of Time Delayed Processes. Part 1: Parameter Optimised Controllers, Aidan O'Dwyer, John Ringwood

Conference papers

An extensive literature exists on the compensation of time delayed processes. It is possible to identify themes that are common to many of the available techniques. The intention of the two parts of this paper is to provide a framework against which the literature may be viewed; Part 1 of the paper considers the use of parameter optimised controllers for the compensation problem, with Part 2 of the paper considering the use of structurally optimised compensators. Conclusions are drawn at the end of Part 2.

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Estimation Of The Parameters Of A Delayed Process Using Open Loop Time Domain Techniques, Morena Stolfa, Aidan O'Dwyer Jan 1999

Estimation Of The Parameters Of A Delayed Process Using Open Loop Time Domain Techniques, Morena Stolfa, Aidan O'Dwyer

Conference papers

In this paper, we present three different approaches to fit the experimental data of a process with time delay in the time domain. Two of the proposed methods are based on the step response, and the third is based on the pulse response. The effectiveness of these techniques is verified by simulation results and by real-time experimental data. Only first order lag plus time delay models are considered in this paper.

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Robust Controller Design For Time Delay Systems Using H-Infinity Techniques, Susan Carr, Aidan O'Dwyer Jan 1999

Robust Controller Design For Time Delay Systems Using H-Infinity Techniques, Susan Carr, Aidan O'Dwyer

Conference papers

Using H-infinity control, the design problem is formulated in terms of user defined weighting polynomials on the process closed-loop sensitivity functions to achieve desired closed-loop performance and robust stability in the presence of process modelling error. In this paper stability conditions , in terms of the process sensitivity functions, are derived for processes containing a pure time delay for the following three design scenarios i) the time delay is neglected in the control design and is considered as part of the unmodelled process dynamics ii) A Pade approximation of the delay is included in the controller design and the effect …

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Pi And Pid Controller Tuning Rules For Time Delay Processes: A Summary. Part 2: Pid Controller Tuning Rules, Aidan O'Dwyer Jan 1999

Pi And Pid Controller Tuning Rules For Time Delay Processes: A Summary. Part 2: Pid Controller Tuning Rules, Aidan O'Dwyer

Conference papers

A summary of tuning rules for the PID control of single input, single output (SISO) processes with time delay, modeled in stable first order lag plus time delay (FOLPD) form, is provided in this part of the paper.

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A Classification Of Techniques For The Compensation Of Time Delayed Processes. Part 2: Structurally Optimised Controllers, Aidan O'Dwyer, John Ringwood Jan 1999

A Classification Of Techniques For The Compensation Of Time Delayed Processes. Part 2: Structurally Optimised Controllers, Aidan O'Dwyer, John Ringwood

Conference papers

Following on from Part 1, Part 2 of the paper considers the use of structurally optimised controllers to compensate time delayed processes.

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Compensation Of Processes With Time Delays, Thomas Heeg, Aidan O'Dwyer Jan 1998

Compensation Of Processes With Time Delays, Thomas Heeg, Aidan O'Dwyer

Conference papers

Methods which allow comparisons in the use of PI and PID controller strategies for the control of first order lag plus time delay processes (FOLPD) are worthy of investigation because of the relative lack of work done in this area. In this paper, strategies for comparing performance and robustness for a PI or PID controlled FOLPD process are analysed and designed. The use of different PID controller structures for processes with time delay is also worth considering in detail. Various PID controller structures are compared by means of servo and regulator time responses, Bode plots and Nyquist plots.

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The Identification And Control Of Processes With Time Delay, Susan Carr, Aidan O'Dwyer Jan 1998

The Identification And Control Of Processes With Time Delay, Susan Carr, Aidan O'Dwyer

Conference papers

The identification of the frequency response and process model parameters of systems with time delay using frequency domain techniques is evaluated in this paper. The performance of both Fourier Transform and Power Spectral Density techniques is considered. The benefits of employing modern model based design and delay compensation techniques, based on the identified process data, are assessed.

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Performance And Robustness Issues In The Compensation Of Folpd Processes With Pi And Pid Controllers, Aidan O'Dwyer Jan 1998

Performance And Robustness Issues In The Compensation Of Folpd Processes With Pi And Pid Controllers, Aidan O'Dwyer

Conference papers

This paper will discuss the compensation of first order lag plus time delay (FOLPD) processes using PI and PID controllers whose parameters are specified using appropriate tuning rules. The gain margin, phase margin and maximum sensitivity of the compensated system as the ratio of time delay to time constant of the process varies, are used as ways of judging the performance and robustness of the system.

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The Gain Scheduled Piece-Wise Adaptive Digital Control Of A Ph Process, Eugene O'Shaughnessy, Aidan O'Dwyer Jan 1998

The Gain Scheduled Piece-Wise Adaptive Digital Control Of A Ph Process, Eugene O'Shaughnessy, Aidan O'Dwyer

Conference papers

The compensation of a pH process is complicated by the non-linear nature of the process titration curve and the significant time delays that typically exist in such processes. This paper will propose the use of a gain scheduled piecewise adaptive PI controller to compensate the process. A pilot plant is controlled, with the control algorithm implemented on a programmable controller. SCADA software displays and trends the plant and controller signals.

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A Comparison Of Some Low Cost Laminates For Antennas Operating In The 2.45 Ghz Ism Band, Max Ammann Jan 1998

A Comparison Of Some Low Cost Laminates For Antennas Operating In The 2.45 Ghz Ism Band, Max Ammann

Conference papers

An evaluation of some low-cost laminates suitable for microstrip patch antennas is presented. Criteria for the selection of substrates for antenna fabrication are given careful consideration. A coaxial-probe fed linearly-polarized rectangular microstrip patch operating at a frequency of 2.45 GHz was fabricated on four different low cost laminates. The substrates used were polyester, epoxy glass (FR-4), a ceramic filled PTFE composite and a woven glass-reinforced hydrocarbon and ceramic thermoset material. Material properties are discussed and the antenna performances are evaluated and compared to one fabricated on a thick glass-loaded microfiber PTFE substrate. An evaluation of some inexpensive microstrip antenna CAD …

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Closed Loop Time Domain Gradient Methods For Parameter And Time Delay Estimation, M, Behan, M Cahill, M. Carry, G Clausen, V. Dooley, N. English, W. Grainger, D. O'Connor, Aidan O'Dwyer, John Ringwood Jan 1997

Closed Loop Time Domain Gradient Methods For Parameter And Time Delay Estimation, M, Behan, M Cahill, M. Carry, G Clausen, V. Dooley, N. English, W. Grainger, D. O'Connor, Aidan O'Dwyer, John Ringwood

Conference papers

This paper discusses the estimation of process parameters and time delay, in a Smith predictor structure, using gradient algorithms in the time domain. A number of estimation algorithms are outlined and applied in simulation to the estimation of the parameters of an appropriate process model. An analytical exploration of the technique is also provided.

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The Control Of A Process With Time Delay By Using A Modified Smith Predictor Compensator, Aidan O'Dwyer, John Ringwood Jan 1996

The Control Of A Process With Time Delay By Using A Modified Smith Predictor Compensator, Aidan O'Dwyer, John Ringwood

Conference papers

A modification is proposed to the Smith predictor compensator structure for the control of a process with time delay. The modification facilitates the achievement of an improved closed loop system regulator response, with little degradation in the corresponding servo response. The compensator design procedure is discussed, and simulation results are provided to demonstrate the applicability of the method.

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Model Parameter And Time Delay Estimation In The Frequency Domain, Aidan O'Dwyer, John Ringwood Jan 1995

Model Parameter And Time Delay Estimation In The Frequency Domain, Aidan O'Dwyer, John Ringwood

Conference papers

This paper discusses the estimation of the parameters (including the time delay) of single input, single output (SISO) process models from an appropriate number of arbitrarily specified points on the process frequency response. The method involves combining an analytical approach with a least squares approach using a gradient algorithm, to provide accurate and robust estimates of the parameters.

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A Frequency Domain Based Self-Tuning Pid Controller, John Ringwood, Aidan O'Dwyer Jan 1994

A Frequency Domain Based Self-Tuning Pid Controller, John Ringwood, Aidan O'Dwyer

Conference papers

Traditionally, both explicit and implicit self-tuning controllers have employed time domain techniques for the identification and tracking of plant and controller parameters. The use of the frequency domain provides concise information on the dynamics of the process which has led to its wide acceptance as a domain for controller design. This paper demonstrates a method employing recursive, on-line measurement of the process frequency response, with a straightforward calculation of PID controller parameters. The computational effort involved is comparable with that of a time domain technique.

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Model Parameter And Time Delay Estimation Using Gradient Methods, Aidan O'Dwyer, John Ringwood Jan 1994

Model Parameter And Time Delay Estimation Using Gradient Methods, Aidan O'Dwyer, John Ringwood

Conference papers

A number of approaches have been proposed for parameter and time delay estimation of process models in single input, single output (SISO) control systems using gradient descent algorithms; some of these approaches involve the selection of a rational polynomial that is used to approximate time delay variations. This paper takes a generalised approach to the investigation of the most appropriate choice of the rational polynomial, and the gradient descent algorithm, to be used.

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A Comparison Of Techniques For Time Delay Estimation, Aidan O'Dwyer Jan 1993

A Comparison Of Techniques For Time Delay Estimation, Aidan O'Dwyer

Conference papers

This paper reviews some of the techniques used for the identification of unknown lumped time delays in single input, single output (SISO) control systems and evaluates a number of these techniques in simulation and in implementation. Both off line and on line identification techniques are considered.

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Standardised Control Techniques For Induction Generators In Both Grid-Connected And Isolated Applications, John Brazil, Aidan O'Dwyer, M. Murphy Jan 1991

Standardised Control Techniques For Induction Generators In Both Grid-Connected And Isolated Applications, John Brazil, Aidan O'Dwyer, M. Murphy

Conference papers

Induction generators are particularly suitable for small hydro applications and are widely used at present. However, with conventional grid-connected techniques, it is not always possible to use them in regions with weak grids because of excessive connection transients. Consequently, their many advantages cannot be fully exploited in these regions. Standardised control systems have been developed by ECS for isolated applications of induction generators and these will now be further developed to permit reduced-transient grid connections.

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Fast Discharges In Thin Liquid Layers, Charles J. Frei, Aidan O'Dwyer Jan 1986

Fast Discharges In Thin Liquid Layers, Charles J. Frei, Aidan O'Dwyer

Conference papers

Several mechanisms can be at work when electrical discharges occur across a thin layer of an insulating liquid. The evidence is derived from the time-lag distributions of series of consecutive discharges when the measurements are performed with a sequence of constant voltage pulses.

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