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Articles 1 - 13 of 13
Full-Text Articles in Controls and Control Theory
Nonlinear Regression Methods For Estimation, Eric B. Nelson
Nonlinear Regression Methods For Estimation, Eric B. Nelson
Theses and Dissertations
Regression techniques are developed for batch estimation and applied to three specific areas, namely, ballistic trajectory launch point estimation, adaptive flight control, and radio-frequency target triangulation. Specifically, linear regression with an intercept is considered in detail. An augmentation formulation is developed. Extensions of theory are applied to nonlinear regression as well. The intercept parameter estimate within the linear regression is used to identify the effects of trim change that are associated with the occurrence of a control surface failure. These estimates are used to adjust the inner loop control gains via a feed-forward command, hence providing an automatic reconfigurable retrim …
Variable Structure Control Of Unsteady Nonlinear Aeroelastic System, With Partial State Information, Sushma Gujjula, Sahjendra N. Singh
Variable Structure Control Of Unsteady Nonlinear Aeroelastic System, With Partial State Information, Sushma Gujjula, Sahjendra N. Singh
Electrical & Computer Engineering Faculty Research
This paper treats the question of control of a two-degree-of-freedom unsteady aeroelastic system with partial state information in the presence of uncertainties. The chosen model describes the plunge and pitch motion of a wing and a single trailing-edge control surface is utilized for the purpose of control. Based on the Lyapunov approach, a variable structure control law is derived. For the control law derivation, the system is treated as the interconnection of two subsystems in which the subsystem associated with the unsteady aerodynamics is input-to-state stable. The stability property of this subsystem is exploited to generate a dominating signal for …
A Wavelet-Based Multiresolution Pid Controller, Shahid Parvez, Zhiqiang Gao
A Wavelet-Based Multiresolution Pid Controller, Shahid Parvez, Zhiqiang Gao
Electrical and Computer Engineering Faculty Publications
A novel controller based on multiresolution decomposition using wavelets is presented. The controller is similar to a proportional-integral-derivative (PID) controller in principle and application. The output from a motion control system represents the cumulative effect of uncertainties such as measurement noise, frictional variation, and external torque disturbances, which manifest at different scales. The wavelet is used to decompose the error signal into signals at different scales. These signals are then used to compensate for the uncertainties in the plant. This approach provides greater expanse over the degree of control applied to the system. Through hardware and simulation results on motion …
A Reference Guide To Smith Predictor Based Methods For The Compensation Of Dead-Time Processes, Aidan O'Dwyer
A Reference Guide To Smith Predictor Based Methods For The Compensation Of Dead-Time Processes, Aidan O'Dwyer
Conference papers
An extensive literature exists on the compensation of time delayed processes. These compensation methods may be broadly divided into parameter optimised controllers, in which the controller parameters are adapted to the controller structure (the most common such controller is the proportional integral derivative, or PID, controller), and structurally optimised controllers, in which the controller structure and parameters are adapted optimally to the structure and parameters of the process model. Important structurally optimised compensator strategies are the Smith predictor and its variations. The purpose of this paper is to extract the essence of the developments in design, tuning and implementation of …
Pid Controller Tuning Of Networked Computer Based Control Systems, Aidan O'Dwyer
Pid Controller Tuning Of Networked Computer Based Control Systems, Aidan O'Dwyer
Conference papers
This contribution discusses the use of PID controller tuning rules to assist in the implementation of network computer based control systems. Such systems typically have a variable time delay associated with the transfer of information. PID controller tuning rules can be directly implemented with minimal capital investment.
Comparative Study Of Two Techniques For Determining Critical Frequency Response Characteristics, Niall O'Connor, Aidan O'Dwyer
Comparative Study Of Two Techniques For Determining Critical Frequency Response Characteristics, Niall O'Connor, Aidan O'Dwyer
Conference papers
The paper presents a review of a comparative study of two separate techniques for obtaining important frequency and time domain characteristics of a system consisting of a process in series with a PI/PID controller in closed loop. The first technique involves the use of a Pseudo Random Binary Sequence (PRBS) to obtain the closed loop frequency response of the system. This closed loop frequency information may then be manipulated to obtain both open loop frequency response information and process model parameters. A further mathematical simulation using Matlab may then be performed independent of the actual process in order to obtain …
Smith Predictor Structure Stability Analysis Using Mikhailov Stability Criterion, Pauline Sourdille, Aidan O'Dwyer, Eugene Coyle
Smith Predictor Structure Stability Analysis Using Mikhailov Stability Criterion, Pauline Sourdille, Aidan O'Dwyer, Eugene Coyle
Conference papers
As is well known, stability is an important requirement for control systems. Due to the nature of time-delay processes, common methods to evaluate stability may be difficult to use. In 1938, Mikhailov proved a frequency response criterion, which is sufficient and necessary for the stability of processes described by known n-th order constant coefficient linear differential equations. This paper presents the Mikhailov method and the application of this method to a Smith predictor structure controlled by a PI controller.
Estimation Of The Parameters Of A Delayed Process Using Open Loop Time Domain Techniques, Yue Zhang, Aidan O'Dwyer
Estimation Of The Parameters Of A Delayed Process Using Open Loop Time Domain Techniques, Yue Zhang, Aidan O'Dwyer
Conference papers
All process investigations should start by a determination of the process model. The modeling strategy used will influence the value of the model parameters, which will in turn affect the controller values determined from tuning rules. This paper will describe an analytical method to identify a model of the dynamic characteristics of a process with a delay by using a tangent and point method, as originally suggested by Murrill, 1967. The methodology has been applied to eight benchmark transfer functions suitable for testing PID controllers, as suggested by Åström and Hägglund, 2000. The main advantages of the modeling approach are …
Modelling And Control Of A Suspension System For Vehicle Applications, Padraig Dowds, Aidan O'Dwyer
Modelling And Control Of A Suspension System For Vehicle Applications, Padraig Dowds, Aidan O'Dwyer
Conference papers
This paper discusses the modelling of passive and active suspension systems in a car, and the subsequent design of appropriate feedback controllers for the active suspension system. The models will be investigated using a quarter car model and a full car model approach.
An Evaluation Of Model-Based Predictive Control, Daniel Czarkowski
An Evaluation Of Model-Based Predictive Control, Daniel Czarkowski
Theses
This thesis attempts to determine whether advanced control algorithms offer any real benefits to the process industry in terms of optimising single-input single output process units. To establish this, an ideal PID controller, Two Degree of Freedom (2 DOF) PID Controller and the Generalised Predictive Controller (GPC) are compared. A common design philosophy is applied based on optimising performance subject to constraints on robustness. Specifically, three different designs are examined; minimum subject to constraints on the gain and phase margin, minimum lAE subject to constraints on the modulus margin and minimum lAE subject to constraints on the input sensitivity function. …
Performance Analysis And Validation Of A Recoverable Flight Control System In A Simulated Neutron Environment, Hong Zhang, W. Steven Gray, Oscar R. Gonzalez
Performance Analysis And Validation Of A Recoverable Flight Control System In A Simulated Neutron Environment, Hong Zhang, W. Steven Gray, Oscar R. Gonzalez
Electrical & Computer Engineering Faculty Publications
This paper introduces a class of stochastic hybrid models for the analysis of closed-loop control systems implemented with NASA's Recoverable Computer System. Such Recoverable Computer Systems have been proposed to insure reliable control performance in harsh environments. The stochastic hybrid models consist of either a stochastic finite-state automaton or a finite-state machine driven by a Markov input, which in turn drives a switched linear discrete-time dynamical system. Their stability and output tracking performance are analyzed using an extension of the existing theory for Markov jump-linear systems. For illustration, a stochastic hybrid model is used to calculate the tracking error performance …
Maintaining A Balance At Undergraduate Degree Level In The Teaching Of Automation And Classical Control Systems, Eugene Coyle, Aidan O'Dwyer
Maintaining A Balance At Undergraduate Degree Level In The Teaching Of Automation And Classical Control Systems, Eugene Coyle, Aidan O'Dwyer
Conference papers
Advances in the past decade in the development and application of Programmable Logic Controllers (PLCs) and Automation Systems in both high technology industrial plants and in the more mainstream manufacturing sectors, has heightened the importance of ensuring that undergraduate degree programme syllabi are designed to adequately cater for the teaching and training of students in automation. Prior to this growth in automation, delivered syllabi in Control Systems on most Electrical Engineering programmes had a theoretical rigour, reflecting the mathematical nature of the topic. A major challenge currently facing departmental lecturing staff and programme coordinators is that of the design of …
Pid Control: The Early Years, Aidan O'Dwyer
Pid Control: The Early Years, Aidan O'Dwyer
Conference papers
This contribution outlines controller developments 1788 – c.1900; 1900-1950: The role of instrument companies; early theoretical description of the PID controller; early tuning of the PID controller; some further developments since 1950; some conclusions.