• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 1998.10a
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• pp.191-196
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• 1998

A new Fuzzy Logic Controller(FLC) called a Gradient-Descent Based Self-Organizing Controller is presented. The Self-Organizing Controller(SOC) has two inputs such as error and change of error, and updates control rules with monitoring a performance measure. There are many works in the SOC which concentrate on the self-organizing ability in control rule base, but have a few research on the performance measure which is akin to sliding mode control. With this procedure, we can get a robust performance measure on the SOC. To verify the perfomance of proposed controller, we have performed for the cart-pole system which is one of the well-known benchmark problem in the control literature.

• The Transactions of the Korean Institute of Electrical Engineers D
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• v.49 no.9
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• pp.526-537
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• 2000

This paper deals with a sliding mode controller with integral compensation in a magnetic suspension system The control scheme comprises an integral controller which is designed for achieving zero steady-steate error under step disturbance input and a sliding mode controller which is designed for enhancing robustness under plant parametric variations. A procedure is developed for determining the coefficients of the switching plane and integral control gain such that the overall closed-loop system has stable eigenvalues. A proper continuous design signal is introduced to overcome the chattering problem. The performance of a magnetically suspended balance beam using the proposed integral sliding mode controller is illustrated. Simulation and experimental results also show that the proposed method is effective under the external step disturbance and input channel parametric variations.

• Journal of Institute of Convergence Technology
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• v.5 no.2
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• pp.13-19
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• 2015

Recently, quadcopters have been popular as aerial drones. The structure of quadcopters is simpler than traditional helicopters and they are easy to construct and maneuver. Various hardware platforms for quadcopters have been developed. However, the controller design is not easy due to the requirement of 6-DOF flights using 4 rotors(control inputs)(under-actuated systems). In order to overcome the underactuation problem, various control methods - PID, LQR, $H_{\infty}$, SMC, backstepping control, and etc. - have been suggested for the control of quadcopters. In this paper, dynamic features and control methods of quadcopters are reviewed and evaluated. Future works are proposed for designing the advanced controllers of quadcopters.

• International Journal of Aeronautical and Space Sciences
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• v.7 no.2
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• pp.121-127
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• 2006

An analysis procedure for the combined problem of control algorithm and aeroelastic system which is based on the computational fluid dynamics(CFD) technique has been developed. The aerodynamic forces in the transonic region are calculated from the transonic small disturbance(TSD) theory. An linear quadratic regulator(LQR) controller is designed to suppress the transonic flutter. The optimal control gain is estimated by solving the discrete-time Riccati equation. The system identification technique rebuilds the CFD-based aeroelstic system in order to form an adequate system matrix which involved in the discrete-time Riccati equation. Finally the controller, that is constructed on the basis of system identification technique, is used to suppress the flutter phenomenon of the airfoil with attached store. This approach, that is, the CFD-based aeroservoelasticity design, can be utilized for the development of effective flutter controller design in the transonic region.

• Proceedings of the KIEE Conference
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• 2006.10c
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• pp.266-268
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• 2006

In this paper, we design a Linear Quadratic Gaussian(LQG) controller for active suspensions. We can improve the inherent suspension problem, trade-off between the ride quality and the suspension travel by selecting appropriate weights in the LQ-objective function. Using an optimization-algorithm, Evolution Strategy(ES), we find the proper control gains for selected frequencies, which have major effects on the vibrations of the vehicle's state variables. The frequencies and proper control gains are used for the neural network data. During a vehicle running, the trained on-line neural network is activated and provides the proper gains for non-trained frequencies.

• 제어로봇시스템학회:학술대회논문집
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• 2005.06a
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• pp.1530-1533
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• 2005

In this paper, we design a Linear Quadratic Gaussian controller for the active suspension. We can improve the inherent suspension problem, trade-off between the ride quality and the suspension travel by selecting appropriate weights in the LQ-objective function. Because any definite rules for selecting weights do not exist, we use an optimization-algorithm, Evolution Strategy (ES) to find the proper control gains for selected frequencies, which have major effects on the vibrations of the vehicle's state variables. The frequencies and proper control gains are used for the neural network data. During a vehicle running, the trained on-line neural network is activated and provides the proper gains for non-trained frequencies. For the full-state feedback control, Kalman filter observes the full states and Fourier transform is used to detect the frequency of the road.

• Journal of Electrical Engineering and information Science
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• v.3 no.1
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• pp.58-66
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• 1998

A continuous, accurate, and robust variable structure tracking controller(CVSTC) is designed for brushless direct drive servo motors(BLDDSM). Although conventional variable structure controls can give the desired tracking performances, there exists an inevitable chattering problems in control input which is undesirable for direct drive systems. With the presented algorithm, not only the chattering problems are removed by using the efficient compensation of the disturbance observer, but also the prescribed tracking trajectory can be obtained using the sliding dynamics when an initial of the desired trajcetory is different from that of a BLDDSM. The design of the sliding mode tracking controller for the prescribed, accurate, and robust tracking performance without the chattering problem is given based on the results of the detailed stability analysis. The usefulness of the suggested algorithm is demonstrated through the computer simulation for a BLDDSM under load variations.

• Proceedings of the Korea Contents Association Conference
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• 2005.05a
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• pp.416-421
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• 2005

In order to use component for various domain, it need to add tangling code. Component reuse suffers from it. AOP was resolved this problem. We present in this paper a component model, called fractal, that added aspect interface using mixin class named joinController interface. Mixin class are used to combine controller object and interceptor object. we design the dynamic weaver that use the decorator pattern, for increase the reuse of aspect.

• 제어로봇시스템학회:학술대회논문집
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• 2000.10a
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• pp.190-190
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• 2000

This paper presents a multirate state feedback control (MRSFC) method for systems sensitive to disturbance and noise based on the multirate estimator design using the current estimator. MRSFC updates the controller output slower than the measurement sampling frequency of system output by a lifting factor R=T$\sub$c//T$\sub$s/. The closed-loop MRSFC system is less sensitive to disturbance and noise due to filtering effect than the conventional single-rate control system. The multirate estimator gain is obtained from solving a conventional pole placement problem such that MRSFC has the same spectrum of eigenvalues in the s-plane as the single-rate control. We applied the proposed multirate state feedback controller to a galvanometer servo system. Simulation and experimental results show that settling and tracking performances are improved compared with a conventional single-rate pole placement control (PPC).

• Proceedings of the KIEE Conference
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• 1997.07c
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• pp.841-843
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• 1997

In this paper we present a Genetic approach to select weighting matrices of LQ(Linear Quadratic) controller for optimal TCSC(Thyristor Controlled Series Capacitor) control. A design of LQ controller depends on choosing weighting matrices. The selection of weighting matrices is usually carried out by trial and error, which is not a trivial problem. We proposed a efficient method using GA of finding weighting matrices for optimal control law. The proposed GA method was applied to design LQ controller of TCSC in one machine infinite bus system and showed good results.