• Proceedings of the KIEE Conference
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• 2008.07a
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• pp.1781-1782
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• 2008

본 논문은 시간 지연을 가지는 이산 시간 비선형 상호 결합 시스템의 분산 퍼지 출력 궤환 제어기의 설계에 대해 연구한다. T-S(Takagi-Sugeno) 퍼지 모델 기법을 이용하여 퍼지 상호 결합 시스템을 구한다. 이를 바탕으로 분산 퍼지 출력 궤환 제어기를 설계하고, 폐루프 시스템의 안정도 충분 조건을 선형 행렬 부등식 (LMI)의 형태로 나타낸다. 설계된 이득값을 통하여 상호 결합 시스템이 안정화됨을 모의실험을 통하여 보인다.

• The Proceedings of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.9 no.3
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• pp.80-87
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• 1995

In this paper, we design the microcontroller-based optimal lead angle control system on the basis of the presented maximum average torque formula of the permanent-type stepping motor with respect to the inductance. We confirm that optimal lead angle enlarges the operating range twice as much and increases the torque over all of the operating range in the case of presented formula as well as experimental results.

• Journal of Institute of Control, Robotics and Systems
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• v.3 no.3
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• pp.280-288
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• 1997

In this paper, we will show that the torque ripple in closed-loop drives of permanent magnet stepping motors is reduced as properly selected lead angle control method. We propose an instantaneous torque equation, which is the function of lead angle, to estimate the influence on torque ripple. We design a closed-loop lead angle control system based on the proposed instantaneous torque equation and measure the instantaneous torque in various excitation modes. It is shown that torque ripple is greatly reduced, as seen from the experimental results as well as from the computer simulation results. For example, torque ripple reduced from 78.25% to 46.82% in the case of 50 PPS single-phase excitation mode operation.

• Journal of the Korean Institute of Intelligent Systems
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• v.19 no.2
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• pp.174-179
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• 2009

We consider the stabilization problem for a class of networked control systems with neutral type of time delays. The neutral type of time-delays occur in controller-to-actuator and sensor-to-controller. The Takagi-Sugeno (T-S) fuzzy model is employed to represent a nonlinear system with neutral type of time-delays. The stabilization via state-feedback is first addressed, and delay-range-dependent stabilization conditions are proposed in terms of linear matrix inequalities (LMIs). Finally, an application example will be given to show the merits and design a procedure of the proposed approach.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.38 no.12
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• pp.1170-1176
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• 2010

This study addresses adaptive control of UAVs(Unmanned Aerial Vehicles) pitch-axis maneuver. The MRAC(Model Referenced Adaptive Control) approach is employed to accommodate uncertainties which are introduced by feedback linearization of pitch attitude control by elevator input. The model uncertainty is handled by adaptation laws which update model parameters while the UAV is under control by the feedback control law. Steady-state pitch attitude achieved by the stabilizing control law is derived to provide insight on the closed-loop behavior of the controlled system. The proposed idea is free of linearization, gain-scheduling procedures, so that one can design high maneuverability of UAVs for pitching motion in the presence of significant model uncertainty.

• Proceedings of the Korea Institute of Convergence Signal Processing
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• 2000.12a
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• pp.205-208
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• 2000

In this paper, we'll show that an improved PDFF controller is obtained by substituting a feedforward compensator in the existing PDFF system with a dual-input describing function, and the controller has the ability of adjusting the bandwidth of a system as well as the phase margin simultaneously. The effectiveness of the proposed controller is confirmed by applying to the DC-motor position control system. As the results of simulation, we know that it is possible to design a controller by which the bandwidth of the closed system and its phase margin are easily adjusted.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.41 no.5
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• pp.19-27
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• 2004

A delay dependent fuzzy $H_2/H_{\infty}$ controller design method for delayed fuzzy dynamic systems is considered. Using delay-dependent Lyapunov function, the asymptotical stability and $H_2/H_{\infty}$ performance problem are discussed. A sufficient condition for the existence of fuzzy controller is presented in terms of linear matrix inequalities(LMIs). A simulation example is given to illustrate the design procedures and performances of the proposed methods.

• Journal of the Korean Society of Propulsion Engineers
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• v.20 no.1
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• pp.28-36
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• 2016

Theoretical model of a variable thrust solid rocket motor with a pintle nozzle was derived. For the chamber pressure control, classical model linearization and proportional-intergral controller was used. And then two types of gain scheduling controller were suggested to imporve controller performance for the non-linear propulsion model. Considering characteristics of systems, control gains were scheduled by chamber pressure or free volume. Step responses of each controllers were compared. As a result, the proper control algorithm about characteristics of variable thrust rocket motor was suggested.

• Journal of the Institute of Convergence Signal Processing
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• v.11 no.1
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• pp.74-79
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• 2010

Many control techniques have been purposed in order to improve the control performances of the control system. The freedom on control in the control system is decided by the number of the closed-loop transfer function which can adjust independently. The design method of the controller with two degrees of freedom(TDOF) is used extensively for following the desired value and rejecting the disturbance. In this paper, the control system with the disturbance observer(DOB) for rejecting the disturbance is transformed by the control system with TDOF and the rejection of a transient response is easy at the starting time and load variation. The design method of the DOB is proposed in the frequency-domain and the control system with TDOF is constructed by using the DOB which is designed with this method. Through the simulation results, the usefulness of the proposed algorithm is proved.

• Journal of the Korean Society of Propulsion Engineers
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• v.16 no.3
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• pp.34-40
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• 2012

A pressure control law to regulate pressure of gas generator is suggested. To design a model based control law, the governing equation which consists of Robert and conservation equation is built and verified through the ground burning test. PID and nonlinear adaptive control laws are designed to analyze the loop response characteristics under the system which has varying eigen properties arisen from combustion volume change. It is suggested that new approach, gain scheduling design, is required to overcome the defects identified from numerical simulation results of the two control laws. The newly suggested scheme shows good control performance even under disturbances and measurement noise.