• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.17 no.6
• /
• pp.1399-1408
• /
• 2013

This paper proposes a new $H_{\infty}$ T-S fuzzy controller with a novel integral control for induction motors which have nonlinear dynamics. The $H_{\infty}$ T-S fuzzy controller is used for the nonlinearity and robustness and weighted integral is used for tracking problem and control performance. A T-S Fuzzy controller is the fuzzy combination of local linear controllers considering the overall stability, and LMI(Linear Matrix Inequlity) is used for determining the gains of linear controllers. The tracking problem of an induction motor is changed into regulator problem by introducing the integral control technique with weighting factor, diminishing the conservatism of $H_{\infty}$ T-S fuzzy controller.

• Journal of Korean Association for Spatial Structures
• /
• v.8 no.4
• /
• pp.73-80
• /
• 2008

The objective of current study is to develop an optimization technique for the seismic actively controlled building structures using active tendon devices by an efficient solution of LQR control gain. In order to solve the active control system, the Ricatti closed-loop algorithm has been applied, and the state vector has been formulated by the transfer matrix and solved by a numerical technique of the trapezoidal rule. The time-delay problem has been also considered by phase compensation. To optimize the performance index, the ratio of the weighted matrix is the design variable, allowable story drift limits of IBC 2000 and tendon forces have been applied as restraint conditions, and the optimum control program has been developed with the algorithm of the SUMT technique. In examples of the optimization problem of eight stories shear buildings, it is evaluated that the optimum controlled building is more suitable in the control of earthquake response than the uncontrolled system and can reduce the performance index to compare with the controlled system with a constant ratio of the weighted matrix.

• Magazine of the Korea Concrete Institute
• /
• v.1 no.2
• /
• pp.121-132
• /
• 1989

유한요소법을 바탕으로 한 프리스트레스트 콘크리트 평면 보-기둥 구조의 후좌굴 거동에 대한 수직해석법을 제시하였다. 콘크리트의 균열, 변형연화 및 PS강재의 항복과 같은 재료 비선형성을 고려하였다. 좌굴 거동 연구에 필수적 요소인 기하학적 비선형성을 Updated Lagraugian Formulation에 의하여고려하였다. 현재의 재료성질 및 변형상태에 부합하는 단분형 평형방정식을 수립하고 이것을 불평형 가중보정에 의한 Newton-Raphson 반복법으로 푼다. 좌굴후 발생하는 하중변형 곡선의 하련부는 비선형 평형 방정식의 해법중 일반적으로 많이 사용되는 가중 단분법이 아니라 변위단분법을 사용함으로써 올바르게 추적한다. 요소내의 재료성질변화는 층적분법에 의하여 고려한다. 본 논문에서는 콘크리트 균열에 의한 중립축이동의 영향을 정확히 고려하기 위하여 추가적으로 축방향변위에 대한 내부자유도를 설정하였다. 본 논문에서 제안하는 방법의 정당성과 응용성을 나타내 보일 수 있는 수직해석 예제를 제시하였다.

• Journal of the Korean Society for Precision Engineering
• /
• v.31 no.2
• /
• pp.105-112
• /
• 2014

This paper proposes a novel $H{\infty}$ T-S Fuzzy controller with a weighted integral action for Interior Permanent Magnet Synchronous Motor(IPMSM) which have nonlinear dynamics. The $H{\infty}$ T-S Fuzzy controller is used for the robustness of nonlinear systems and the weighted integral action is used for the tracking problem and the improvement of control performance. A T-S Fuzzy controller is designed by combining the local controllers with the overall stability, and LMI(Linear Matrix Inequality)is used to determine the gains of linear controllers. The tracking problem of IPMSM is changed into regulator problem by introducing the integral action and the weighting factor gives flexibility to a $H{\infty}$ fuzzy controller.

• Nuclear Engineering and Technology
• /
• v.27 no.3
• /
• pp.336-343
• /
• 1995

The Self Tuning Regulator(STR) method which is an approach of adaptive control theory, is ap-plied to design the fully automatic power controller of the nonlinear reactor model. The adaptive control represent a proper approach to design the suboptimal controller for nonlinear, time-varying stochastic systems. The control system is based on a third­order linear model with unknown, time-varying parameters. The updating of the parameter estimates is achieved by the recursive extended least square method with a variable forgetting factor. Based on the estimated parameters, the output (average coolant temperature) is predicted one-step ahead. And then, a weighted one-step ahead controller is designed so that the difference between the output and the desired output is minimized and the variation of the control rod position is small. Also, an integral action is added in order to remove the steady­state error. A nonlinear M plant model was used to simulate the proposed controller of reactor power which covers a wide operating range. From the simulation result, the performances of this controller for ramp input (increase or decrease) are proved to be successful. However, for step input this controller leaves something to be desired.