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In the last two years, we have developed some new ideas and techniques for the control of chaotic nonlinear systems using conventional feedback controllers design methods, for both discrete-time and continuous-time systems [1-4], where the target position is either an (unstable) equilibrium point or an (unstable) limit cycle of the chaotic system. In this paper, we further provide a rigorous mathematical...
A novel technique for identifying reduced-order models in the closed-loop is presented. The method arrives at a process model and its corresponding compensator in an iterative fashion by introducing a series of step chan at the manipulated variable. The bias introduced into the identification data set by the closed-loop system, coupled with a control-relevant prefilter, yields a model whose corresponding...
An anticipatory neuro-fuzzy controller has been developed which combines traditional fuzzy logic with feedback concepts and a neural network to predict system behavior. Fuzzy rules in the system are 'nested' so that it is not necessary to evaluate all rules at each time step if some smaller subset of rules will produce acceptable system behavior. Anticipatory neuro-fuzzy control does not require that...
A new precompensation technique is demonstrated that improves the performance of both optimal regulators and fixed-final-time control systems. This paper applies the technique to improve the response of an unstable Multi-Input-Multi-Output aircraft model with a lightly damped, highly oscillatory wing bending mode.
This paper describes a laboratory project for teaching the fundamental concepts of electrohydraulic servomechanism to undergraduate/graduate control engineering students. Although electrohydraulic servomechanisms have dominated the industrial control scene for quite some time, typical control courses do not have these as an integral part of the overall laboratory experience. Thus, the main objective...
It is commonly believed that fuzzy logic control (FLC) has excellent robust characteristics. In this paper, fuzzy logic-based roll controllers are designed to control wing-rock motion of a free-to-roll stinged delta wing. The dynamics of an aircraft is a complex function of the flight conditions. The free-to-roll stinged delta wing provides investigations of these variations as well as the exhibited...
In recent years, the study in fuzzy control has been received extensive attention. However, most of available fuzzy control rules currently used are based on trial and error as it is difficult to predict fuzzy parameters systematically. In this study, we proposed a fuzzy model for a pneumatic chamber and applied an "inverse plant" technique, incorporating above fuzzy model, to develop suitable...
The paper focuses on the problem of explicitly generating open loop strategies for steering control systems with left-invariant vector fields on the Lie group of rigid rotations SO(3). Both systems with and without drift are considered as well as systems with three, two or one input(s). For each of these cases, if possible, we present a constructive solution to the steering problem. The most interesting...
We investigate robust decentralized adaptive controller design for interconnected systems. Motivated by real mechanical systems, we consider a general representation of interconnections when the strength of the interconnections is bounded by a pth-order polynomial in states. This is in contrast to other works which have made simpler assumptions about the strength of the interconnections. The possible...
In this paper, the state feedback decoupling control for bilinear systems is discussed. The sufficient condition for the existence of decoupling controller and the design procedure are given. A real world example, the headbox control of a paper machine, demonstrates the efficiency of the proposed method.
The static output feedback control problem for discrete linear quasi-weakly coupled stochastic systems is studied A parallel reduced-order algorithm is developed which is very efficient, since the algorithm decomposes a high order system into a low order system. The low order system is represented by six Lyapunov equations which may be solved in parallel to reduce computational time. The required...
Sliding mode control is a standard approach to tackle the parametric and modeling uncertainities of a non-linear system. However, the robust control obtained by using sliding mode has a price, which is the high frequency chattering encountered during the digital implementation of the control. The idea of introducing a boundary layer around the switching surface and approximating a continuous control...
This paper addresses the design of fixed order dynamic compensators for variable structure control applied to a linear multivariable plant. The variable structure control law considered in this paper is a function of the outputs and the compensator states. A methodology is developed to design the sliding surface and the parameter matrices of the compensator simultaneously so that a specific performance...
This paper deals with the design of robust digital controllers for gun-turret systems which exhibit large parameter and high frequency unmodeled uncertainties. A method based on quadratic stability criteria is developed to search control laws which achieve possible maximum tolerance for system uncertainties while remaining high degree of tracking and reulating precision. Simulated results are shown...
Equations for the loop transmission bound for the multivariable Quantitative Feedback Theory are presented nere. These equations are useful in the computer - aided design of multivariable control systems.
Much of the current body of control achieves a generic coverage of application areas by having a generic representation of the systems to be controlled. Instead of having a generic representation of systems, we propose a generic method for automatically deriving system-specific representations. We call this approach metamodelling and we use the Bond-Graph representation as a basis for this. This allows...
In this paper we investigate under what conditions the stabilizability of a given plant G(??o,s) implies the stabilizability of every plant G(??,s) {G(??,s) | ?? ??}. These new general conditions for robust diagonal stabilization of a plant set are based on topological connectedness. When the conditions of our main theorem are satisfied, we say that the set {G(??,s)} is topologically path connected...
In this work, Banach contraction mapping principle is used to assess the degree of stability robustness of linear, time varying systems when controlled by dynamic feedback controllers. The results are given for both continuous and discrete systems directly in terms of perturbation bounds, system and design parameters and are valid for various unstructured nonlinear perturbations and additive disturbances.
In the first part of this paper, some of the better ways of representing discrete-time systems, than the conventional discrete equations and the z transfer functions, are studied from the controller design and real-time computation points of view. Among those considered, the ?? operator and the Euler operator forms are recommended. In the second part of the paper, a definition of discrete-time models...
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