• Journal of the Korean Institute of Intelligent Systems
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• v.15 no.2
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• pp.127-134
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• 2005

This paper proposes a nonlinear fuzzy PID controller with variable parameters to improve slow rising time and divergence occurred by limited input spaces and a resultant limited control input during fuzzification in a fuzzy PID controller with fixed parameters, and describes the design principle and tracking performance of a proposed fuzzy PID controller. The parameters of a proposed controller are adjusted by the stability conditions derived from 'small gain theorem' and satisfy the BIBO stability of overall control system.

• Journal of the Korean Institute of Intelligent Systems
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• v.14 no.7
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• pp.807-815
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• 2004

This paper describes the design principle of a fuzzy PID controller with fixed parameters, proposes the simulified form of a fuzzy PID controller to increase the computational efficiency and analyzes stability of a proposed fuzzy PID controller. After a detailed stability analysis using ‘small gain theorem’, a simple and practical sufficient condition for the BIBO stability of the overall feedback control system is derived. The derived stability condition offers a calculation method to obtain parameters of a fuzzy PID controller from parameters of a stable PID controller. Finally several computer simulations are executed to confirm the effectiveness of the fuzzy PID controller with fixed parameters.

• Proceedings of the KIEE Conference
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• 2003.11b
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• pp.111-114
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• 2003

In this paper, we consider the stabilization and $H_\infty$ control of linear systems with static output feedback control. The static output feedback control represents the simplest closed-loop control that can be realized in practice, and, moreover, it is less expensive to be implemented and is more reliable. In spite of its advantages, it is one of the open problems which is not sloved analytically or numerically yet. After decompose the closed-loop system into feedback form, by adopting the small gain theorem, we obtain a sufficient condition for stabilization and a sufficient condition for It control expressed as linear matrix inequalites. Finally, we show the usefulness of our results by a numerical example.