A procedure is presented for optimizing weight functions, when determining /spl Hscr//sub /spl infin// controllers by loop shaping for SISO plants with model uncertainty. The optimization is combined with an evaluatio...
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A procedure is presented for optimizing weight functions, when determining /spl Hscr//sub /spl infin// controllers by loop shaping for SISO plants with model uncertainty. The optimization is combined with an evaluation method to give a final tuning of the controller. The basic idea of both the optimization and the parameter tuning is to formulate separate criteria for low, mid and high frequency closed loop properties. By doing so, the trade off between stability margins, high frequency robustness and low frequency performance is elucidated and, hence, the final choice of parameters is facilitated. The resulting controller has the inherent optimality features of /spl Hscr//sub /spl infin// controllers as well as a robustness to explicit plant uncertainties, guaranteed by the use of Horowitz bounds. In the procedure, low frequency performance is optimized subject to these bounds and a restricted high frequency loop gain. The method is applied to two different uncertain plants, and the results are evaluated in terms of robust performance and evaluated against optimized PID controllers. The comparison shows that with identical tuning parameters and for a given control activity the /spl Hscr//sub /spl infin// controllers achieve better low frequency performance at the same time as the maximum sensitivity is superior.
This paper addresses networking and traffic control problems in network systems along with the potential for introducing soft-computing applications at supervisory control level. The incentive Stackelberg strategy con...
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This paper addresses networking and traffic control problems in network systems along with the potential for introducing soft-computing applications at supervisory control level. The incentive Stackelberg strategy control concept was introduced to the networking model that comprises subsidiary systems of users and of network. A linear strategy is proposed for the elastic traffic problem, and results are demonstrated and illustrated via Kelly's (1997) example. The presented method is extended to the non-elastic traffic problem and results are also illustrated via a slightly modified Kelly example. Ways of employing combined analytical and soft-computing approaches and techniques in a hybrid framework have been investigated. A fuzzy-Petri-net supervisor is proposed to implement the strategic decision and control layer. Insofar obtained results are rather encouraging, and this research continues further towards possible implementation as well as some open theoretical issues.
Computation of an ARMA covariance function is a common ingredient in analysis and synthesis of various problems in stochastic control, estimation and signal processing. In this paper, we present an algorithm based on ...
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In this paper the output-tracking problem of a class of composite nonlinear systems is studied. Composite system can be represented solely by models on the grounds of its inputs and measurable outputs. It is assumed t...
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In this paper the output-tracking problem of a class of composite nonlinear systems is studied. Composite system can be represented solely by models on the grounds of its inputs and measurable outputs. It is assumed that (i) the plant system belongs to aclass of composite non linear systems, and that the fuzzy logic control system applied can efficiently use adjustable parameters to approximate its non linear system function. The new theorem guarantees the synthesized indirect fuzzy adaptive control does ensure stable output tracking and possesses the ability to reduce the number of fuzzy rules.
The problem of the pricing equilibrium in multi-service priority-based networks isstudied by using Stackelberg game theory. Some concepts of the game theory were revisited first. Then, the existing results on two-user...
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The problem of the pricing equilibrium in multi-service priority-based networks isstudied by using Stackelberg game theory. Some concepts of the game theory were revisited first. Then, the existing results on two-user, twolevel Nash problem was reviewed briefly. Following this background, a new one-leader, two-level, two-user incentive Stackelberg strategy was derived and proved by employing the time delay involved.
A characteristic feature of the neural network models is the large number of parameters. A model offering many parameters usually gives rise to problems, and the variance contribution to the modeling error might be ve...
A characteristic feature of the neural network models is the large number of parameters. A model offering many parameters usually gives rise to problems, and the variance contribution to the modeling error might be very high. Therefore, it is crucial to find the model with the optimal number of parameters. In this paper two techniques of selection of the optimal number of model parameters are described and compared: explicit and implicit regularization techniques. Model validation forms the final stage of an identification procedure with the aim of assessing objectively whether the identified model agrees sufficiently well with the observed data. In this paper the reliability of the correlation-based validation tests and the χ2-test is analyzed.
A neuro controller for high precision manoeuvring of underwater vehicles require special attention to a number of factors including thruster and vehicle’s nonlinearities, couplings which exist between various degrees...
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A neuro controller for high precision manoeuvring of underwater vehicles require special attention to a number of factors including thruster and vehicle’s nonlinearities, couplings which exist between various degrees of freedom as well as effects of the sea currents. The neuro control system for underwater vehicle maneouvring described here is based on the conventional controller supported with the so called adaptive neural network.
An explicit self-tuning controller based on the Takagi-Sugeno fuzzy model of the process is proposed. The fuzzy model is represented as a linear regression model whose parameters are functions of some of the process v...
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An explicit self-tuning controller based on the Takagi-Sugeno fuzzy model of the process is proposed. The fuzzy model is represented as a linear regression model whose parameters are functions of some of the process variables. Such a model can be considered as a linear time-varying model whose parameter values are known at every moment. The pole placement design procedure modified for time-varying systems is applied to obtain the polynomial controller parameters that provide the desired closed-loop poles. The proposed algorithm is very simple, and thus suitable for on-line controller design in adaptive control systems.
In this paper, a model based fed-batch strategy for the cultivation of the bacterium Photorhabdus luminescens is proposed. The development of an appropriate trajectory for bacterial growth and substrate feed rate can ...
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In this paper, a model based fed-batch strategy for the cultivation of the bacterium Photorhabdus luminescens is proposed. The development of an appropriate trajectory for bacterial growth and substrate feed rate can be obtained using the theory of flat systems introduced by Fliess et al. (1992). To avoid deviations from a desired trajectory caused by model uncertainties or disturbances, a nonlinear controller is presented allowing closed loop control of the fermentation process.
This paper presents a modification to the Kandadai and Tien’s learning algorithm for tuning a fuzzy-neural controller that is able to automatically generate a knowledge base. Tuning is based on reinforcements from a ...
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This paper presents a modification to the Kandadai and Tien’s learning algorithm for tuning a fuzzy-neural controller that is able to automatically generate a knowledge base. Tuning is based on reinforcements from a dynamical system, thus giving a pseudosupervised learning scheme using error backpropagation. Originally, a weak reinforcement in the form of a binary failure signal was assumed which proved to be insufficient in terms of steady-state error. Therefore, a continuous reinforcement signal is applied enabling the system to correct the error as well as decreasing the overall control effort in the learning phase.
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