Search results for "Control theory"
showing 10 items of 1333 documents
Parameter Identification of a Winding Function Based Model for Fault Detection of Induction Machines
2018
Prediction of machines' faulty parts is important in industrial applications in order to reduce productivity losses. As far as electrical machines are considered, a model-based fault diagnosis approach is usually used for this purpose. The model is derived from the modified winding function theory and hence, it requires a considerable amount of parameters at various operating conditions in order to be successfully used. However, the complete set of parameters is difficult to be obtained, as manufacturers of electric machines normally provide only the parameters that describe simple motor models (e.g. T-equivalent circuit at rated conditions). Therefore, the current work presents a method th…
Input-output finite-time stability of positive switched linear systems with state delays
2013
This paper is concerned with the problem of input-output finite-time stability (IO-FTS) for a class of discrete-time positive switched systems with time-varying delays. Two sufficient conditions for the existence of IO-FTS of such systems with respect to two different input signals are presented, respectively. All the results obtained are formulated in a set of linear inequalities. Two numerical examples are given to illustrate the effectiveness of the proposed results.
Fast solution of radial distribution networks with automated compensation and reconfiguration
2000
Abstract Optimal operation of radial distribution networks with automated compensation and reconfiguration requires the solution of a combinatorial optimisation problem, since the variables are the on/off status of capacitor banks and the open/close status of tie-switches. The solution approaches recently proposed use iterative algorithms such as genetic algorithms, simulated annealing and tabu search, for which the network needs to be solved in different configurations and at different compensation levels. The aim of this evaluation is that of attributing a quality index to each solution so that all the solutions can be suitably ordered. In an automated network, any configuration can be ob…
Discrete-time static output-feedback semi-decentralized H<inf>&#x221E;</inf> controller design: An application to structural vibratio…
2012
In this work, we present a new and effective method to design discrete-time static output-feedback H ∞ controllers. This new method, based on a Linear Matrix Inequality (LMI) formulation, introduces a suitable transformation of the LMI variables that allows to obtain an explicit expression for the output-feedback gain matrix. Moreover, for problems involving a set of subsystems with information exchange constraints, a convenient structure on the LMI variables can be imposed in order to design semi-decentralized controllers, where the corresponding output-feedback gain matrix has a prescribed zero-nonzero structure. To illustrate the proposed methodology, discrete-time static velocity-feedba…
Induced &#x2113;<inf>2</inf> control of discrete-time Takagi-Sugeno fuzzy systems with time-varying delays via dynamic output feedback
2012
This paper is concerned with analyzing a novel model transformation of discrete-time Takagi-Sugeno (T-S) fuzzy systems with time-varying delays and applying it to dynamic output feedback (DOF) controller design. A new auxiliary model is proposed by employing a new approximation for time-varying delay state, and then delay partitioning method is used to analyze the scaled small gain of this auxiliary model. A sufficient condition on discrete-time T-S fuzzy systems with time-varying delays, which guarantees the corresponding closed-loop system to be asymptotically stable and has an induced l 2 disturbance attenuation performance, is derived by employing the scaled small gain theorem. Then the…
Setpoints compensation in industrial processes via multirate output feedback control
2013
This paper investigates the setpoints compensation for a class of complex industrial processes. Plants at the device layer are controlled by the local regulation controllers, and a multirate output feedback control approach for setpoint compensation is proposed such that the subsystems can reach the dynamically changed setpoints and the given economic objective can also be tracked via certain economic performance index (EPI). First, a sampled-data multivariable direct output feedback proportional integral (PI) controller is designed to regulate the performance of the subsystems. Second, the outputs and control inputs of the plants at the device layer are sampled at operation layer sampling …
Role of the colored noise in a FitzHugh-Nagumo system driven by a periodic signal
2007
During these last years the interest in neuronal dynamics increased. The study of this kind of system has been carried out by using the FitzHugh-Nagumo (FHN) model that is a simplified modification of the Hodgkin-Huxley model. Many interesting phenomena can be observed in the presence of fluctuations: modification of detection threshold by manipulation of noisy parameters (FHN model), noise-induced activation and coeherence resonance for suitable noise amplitude (absence of periodic signal), resonant activation for high periodic signals and noise reduction, intrinsic stochastic resonance (ISR) in Hodgkin-Huxley neuron and the enhancement of a weak signal by tuning the subthreshold intrinsic…
Optimization of a thermomagnetic motor
2015
In this paper, an approach towards the optimization of the Curie motor is presented. The approach is based on a thermal-magnetic coupled dynamic model of the motor, which is obtained by assuming the use of a ferromagnetic material working at temperatures near the Curie point. An analytical expression of the generated torque, which links this quantity to the magnetic, thermal, and geometrical parameters of the generated torque, is given. The expressions of speed and torque are derived and related to the thermal properties of the machine and are used as optimization indexes in an optimization procedure. The aim of the optimization process is to obtain a machine able to rotate constantly at th…
Adaptive type-2 fuzzy control of non-linear systems
2009
The paper describes the development of two different type-2 adaptive fuzzy logic controllers and their use for the control of a non linear system that is characterized by the presence of bifurcations and parameter uncertainty. Although a type-2 fuzzy logic controller is able to handle the non linearities and the uncertainties present in a system, its robustness and effectiveness can be increased by the use of an opportune adaptive algorithm. A simulation study was conducted to compare the behavior of adaptive controllers with that of simple type-1 and type-2 fuzzy logic controllers. The system to be controlled, used for the simulation, is a continuous bioreactor for the treatment of mixed w…
Adaptive type-2 fuzzy logic control of a bioreactor
2010
Two adaptive type-2 fuzzy logic controllers with minimum number of rules are developed and compared by simulation for control of a bioreactor in which aerobic alcoholic fermentation for the growth of Saccharomyces cerevisiae takes place. The bioreactor model is characterized by nonlinearity and parameter uncertainty. The first adaptive fuzzy controller is a type-2 fuzzy-neuro-predictive controller (T2FNPC) that combines the capability of type-2 fuzzy logic to handle uncertainties, with the ability of predictive control to predict future plant performance making use of a neural network model of the nonlinear system. The second adaptive fuzzy controller is instead a self-tuning type-2 PI cont…