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Articles 1 - 9 of 9
Full-Text Articles in Controls and Control Theory
Comparison Between Theoretical And Practical Phase Computation, Pauline Sourdille, Aidan O'Dwyer
Comparison Between Theoretical And Practical Phase Computation, Pauline Sourdille, Aidan O'Dwyer
Conference papers
Transfer functions which are a composite of delay terms cause problems for computer packages, such as MATLAB, in calculating the frequency response open loop transfer function, as the form of the open loop transfer function is irrational. So, the delay terms have to be approximated. There are several ways to evaluate a delay term. A calculator such as MATHEMATICA uses the exact representation of the delay called the Euler form. A computer package such as MATLAB uses a rational approximation for the delay. Using the MATLAB built-in function pade(n,tau), the open loop transfer function of a system with delay can …
State Feedback Integral Control By Velocity-Based Multiple Model Networks, Ruiyao Gao, Aidan O'Dwyer
State Feedback Integral Control By Velocity-Based Multiple Model Networks, Ruiyao Gao, Aidan O'Dwyer
Conference papers
Velocity-based (VB) multiple model networks have the advantage of allowing the capture of the dynamics of non-linear systems when compared to conventional multiple model networks, for they build a direct relationship between the non-linear system and the VB linearisation. To have the best use of modelled dynamic information for the controller design, this paper proposes a novel controller design approach, which associates an integral action with state feedback in local controller design. It overcomes the difficulty in the implementation of the velocity-based approach, which normally involves deducing the differential signal. It holds continuity with linear control theory in the analysis …
Tuning Rules For Pi And Pid Control Of Time Delayed Processes: Some Recent Developments, Aidan O'Dwyer
Tuning Rules For Pi And Pid Control Of Time Delayed Processes: Some Recent Developments, Aidan O'Dwyer
Conference papers
The ability of PI and PID controllers to compensate many practical processes has led to their wide acceptance in industrial applications. The requirement to choose two or three controller parameters is most easily done using tuning rules. Starting with a general discussion of industrial practice, the paper will discuss, in particular, recent work in tuning rule development for processes with time delay.
Enhancing Process Performance Through Automatic Control, Aidan O'Dwyer
Enhancing Process Performance Through Automatic Control, Aidan O'Dwyer
Conference papers
The proportional integral derivative (PID) controller is the most dominant form of automatic controller in industrial use today. With this technique, it is necessary to adjust the controller parameters according to the nature of the process. Thus, for effective control of a pasteurisation process, for example, specific values need to be chosen for the P, I and D parameters, which will be different for the values required to control, for example, a distillation column. This tailoring of controller to process is known as controller tuning.
Control Loop Performance Assessment: A Classification Of Methods, Niall O'Connor, Aidan O'Dwyer
Control Loop Performance Assessment: A Classification Of Methods, Niall O'Connor, Aidan O'Dwyer
Conference papers
This paper presents an overview of a number of controller performance assessment techniques. The techniques discussed are divided into five categories, namely, time domain assessment, frequency domain assessment, minimum variance control (MVC) as a benchmark, statistical analysis, and other more ‘problem specific’ assessment techniques. Recent work, by various authors, in each of the five categories is outlined.
System Identification Using The Delta Operator, Aidan O'Dwyer
System Identification Using The Delta Operator, Aidan O'Dwyer
Conference papers
The aim of this contribution is to communicate, to a wide audience in signal processing and telecommunications, work that has been carried out, primarily in control engineering, on the use of alternative discrete time operators to the z-domain operator. The advantages of the delta domain operator will be communicated using examples, primarily with the aid of plotted results, to give a creative and easily understood impact. Some original work carried out by the author on identification issues will also be communicated.
Determination Of The Phase Of A Transfer Function: Theory Versus Practice, Pauline Sourdille, Aidan O'Dwyer
Determination Of The Phase Of A Transfer Function: Theory Versus Practice, Pauline Sourdille, Aidan O'Dwyer
Conference papers
In control systems, a way to evaluate the stability of a system is to determine the magnitude and phase of the open loop system transfer function in the frequency domain. But due to the nature of the phase expression, practice and theory are not aligned. Some problems arise when the phase is determined, caused by the properties of the arctan function. This paper analyses these phase problems for a third order lag system and a third order lag with time delay system. It also presents modifications to obtain the analytically correct phase values from the computed values.
Implementation Of New Modified Smith Predictor Designs, Pauline Sourdille, Aidan O'Dwyer
Implementation Of New Modified Smith Predictor Designs, Pauline Sourdille, Aidan O'Dwyer
Conference papers
This paper outlines two modified Smith predictors developed previously by the authors and then presents the implementation results of these structures for the control of a pilot scale heating and ventilation system, the PT 326 process trainer from Feedback Instruments Ltd. These results are compared to the results obtained with a Smith predictor structure.
Using Information Technology To Enhance Control Engineering Education: Some Experiences, Aidan O'Dwyer
Using Information Technology To Enhance Control Engineering Education: Some Experiences, Aidan O'Dwyer
Conference papers
In the past decade, the use of computer based design and analysis tools, such as MATLAB/SIMULINK, has revolutionised practice in Control Engineering. Concepts that were previously only understandable after sustained mathematical analysis or experimental work may now be readily simulated on the computer. Over the past four years, the author has experimented with the use of MATLAB/SIMULINK, in the lecture and laboratory environment, with degree and taught masters students in control engineering at Dublin Institute of Technology (DIT). It has been found that the tool helps to increase student understanding of challenging topics, to act as motivation to further exploration …