Wyniki wyszukiwania - BazTech

1

An observer-based adaptive fuzzy control for prescribing drug dosage in cancer treatment

Bandpey Razieh Firouzpour, Kalat Ali Akbarzadeh

Biocybernetics and Biomedical Engineering

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2022

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Vol. 42, no. 4

1137--1148

EN

In this study, an observer-based adaptive fuzzy controller for prescribing drug dosage in cancer treatment is presented. In the controller design, it is supposed that only the tumor cells and the concentration of Interleukin-2 (IL-2) are measurable. After defining new state variables for the system, a state observer is employed to estimate the unmeasurable state when the unknown dynamic functions of the system are approximated by the fuzzy systems. The stability of the closed-loop system is demonstrated using the Lyapunov theory. Simulation results show the good performance of the observer-based controller taking into account the unknown system dynamics.

2

Comparative Study of Optimised Artificial Intelligence Based First Order Sliding Mode Controllers for Position Control of a DC Motor Actuator

Nyong-Bassey B. E., Akinloye B.

Journal of Automation Mobile Robotics and Intelligent Systems

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2016

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Vol. 10, No. 3

58--71

EN

This paper aims at critically reviewing various sliding mode control measures applied to Permanent Magnet DC Motor actuator for position control. At first, a hybrid sliding mode controller was examined with its advantages and disadvantages. Then, the smooth sliding mode controller in the same manner. The shortcomings of the two methods were overcome by proper switch design and also using tanh-sinh hyperbolic function. The sliding mode controller switches on when either disturbance or noise is detected. Genetic Algorithm Computational tuning technique is employed to optimize the gains of the controllers for optimal response.The performance of the proposed controller architecture, as well as the reviewed controllers, have been compared for performance evaluation with respect to several operating conditions. This includes load torque disturbance injection, noise injection in a feedback loop, motor nonlinearity exhibited by parameters variation, and a step change in reference input demand.

3

LMI-based adaptive fuzzy integral sliding mode control of mismatched uncertain systems

Mnasri C., Gasmi M.

International Journal of Applied Mathematics and Computer Science

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2011

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Vol. 21, no 4

605-615

EN

Integral sliding mode design is considered for a class of uncertain systems in the presence of mismatched uncertainties in both state and input matrices, as well as norm-bounded nonlinearities and external disturbances. A sufficient condition for the robust stability of the sliding manifold is derived by means of linear matrix inequalities. The initial existence of the sliding mode is guaranteed by the proposed control law. The improvement of the proposed control scheme performances, such as chattering elimination and estimation of norm bounds of uncertainties, is then considered with the application of an adaptive fuzzy integral sliding mode control law. The validity and efficiency of the proposed approaches are investigated through a sixth order uncertain mechanical system.

4

Robust adaptive fuzzy filters output feedback control of strict-feedback nonlinear systems

Tong S., Liu C., Li Y.

International Journal of Applied Mathematics and Computer Science

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2010

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Vol. 20, no 4

637-653

EN

In this paper, an adaptive fuzzy robust output feedback control approach is proposed for a class of single input single output (SISO) strict-feedback nonlinear systems without measurements of states. The nonlinear systems addressed in this paper are assumed to possess unstructured uncertainties, unmodeled dynamics and dynamic disturbances, where the unstructured uncertainties are not linearly parameterized, and no prior knowledge of their bounds is available. In recursive design, fuzzy logic systems are used to approximate unstructured uncertainties, and K-filters are designed to estimate unmeasured states. By combining backstepping design and a small-gain theorem, a stable adaptive fuzzy output feedback control scheme is developed. It is proven that the proposed adaptive fuzzy control approach can guarantee the all the signals in the closed-loop system are uniformly ultimately bounded, and the output of the controlled system converges to a small neighborhood of the origin. The effectiveness of the proposed approach is illustrated by a simulation example and some comparisons.

5

Vision-Based Mobile Robot Navigation

Berrabah S. A., Colon E.

Journal of Automation Mobile Robotics and Intelligent Systems

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2008

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Vol. 2, No. 4

7-13

EN

This paper presents a vision-based navigation system for mobile robots. It enables the robot to build a map of its environment, localize efficiently itself without use of any artificial markers or other modifications, and navigate without colliding with obstacles. The Simultaneous Localization And Mapping (SLAM) procedure builds a global representation of the environment based on several size limited local maps built using the approach introduced by Davison [1]. Two methods for global map are presented; the first method consists in transforming each local map into a global frame before to start building a new local map. While in the second method, the global map consists only in a set of robot positions where new local maps are started (i.e. the base references of the local maps). In both methods, the base frame for the global map is the robot position at instant . Based on the estimated map and its global position, the robot can find a path and navigate without colliding with obstacles to reach a goal defined the user. The moving objects in the scene are detected and their motion is estimated using a combination of Gaussian Mixture Model (GMM) background subtraction approach and a Maximum a Posteriori Probability Markov Random Field (MAP-MRF) framework [2]. Experimental results in real scenes are presented to illustrate the effectiveness of the proposed method.

6

Fuzzy logic control of PMSM fed by voltage source inverter associated to hybrid current controller

Kadjoudi M., Benbouzid M.E.

Archives of Electrical Engineering

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2007

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Vol. 56, nr 3-4

279-297

EN

For most applications, the load torque and parameters variations are important, requiring robust control methods to achieve a good regulation of the motor speed over all operating conditions. In this paper, a fuzzy algorithms for speed control of permanent magnet synchronous motor (PMSM) drive are proposed. An adaptive FLC is also described and its performances have been investigated for the case of vector controlled PMSM. A comparison between FLC and fixed gain PI controller is presented by simulation results, that verify effectiveness of the approach under various operating conditions and provide fast and robust control. The paper presents also a detailed analysis of hysteresis and hybrid current controllers for PMSM fed by conventional voltage source inverter. In addition, fixed switching frequency at different operating conditions becomes possible with the proposed hybrid current controller.

PL

Zmienność momentu i parametrów układu jest problemem w wielu napędach. Wymusza ona stosowanie odpowiedniej metody sterowania w celu zapewnienia odpornej regulacji prędkości w catym zakresie warunków pracy. W artykule przestawiono algorytmy logiki rozmytej dla regulacji prędkości silnika synchronicznego o magnesach trwałych (PMSM). Opisano adaptacyjne sterowanie rozmyte (FLC) i jego działanie w sterowaniu wektorowym PMSM. Porównano FLC z regulatorem PI o stałym wzmocnieniu. Badania symulacyjne przeprowadzone dla różnych warunków pracy wykazały, że proponowany układ sterowania jest szybki i odporny na zmiany parametrów. Przedstawiono szczegółowe porównanie histerezowego regulatora prądu dla PMSM zasilanego z dwu- i trójpoziomowego przekształtnika napięcia. Przebiegi harmoniczne dla opisywanych układów sterowania opracowano za pomocą szybkiej transformaty Fouriera. W efekcie uzyskano stałą częstotliwość łączeń w różnych warunkach pracy przekształtnika.