• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1995년도 Proceedings of the Korea Automation Control Conference, 10th (KACC); Seoul, Korea; 23-25 Oct. 1995
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• pp.47-50
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• 1995

This paper concerns an adaptive control scheme which is an extension of the simplified adaptive control. Originally, the SAC approach was developed based on the command generator tracker (CGT) theory for perfect model tracking. An attractive point of the SAC is that a control input can be synthesized without any prior knowledge about plant structure. However, a feedforward dynamic compensator of the CGT is removed from the basic structure of the SAC. This deletion of the compensator makes perfect model tracking difficult against even a step input. In this paper, an adaptive control system is redesigned to achieve perfect model tracking for as long as possible by reviving the dynamic compensator of the CGT. The proposed method is applied to slewing control of a flexible space structure and compared to the SAC responses.

• 제어로봇시스템학회논문지
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• 제20권3호
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• pp.261-269
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• 2014

This paper provides an overview of the basics and recent studies of Lyapunov-based nonlinear adaptive control, the aim of which is to improve or maintain the performance and stability of the closed-loop system by cancelling out the presumable uncertainties in the nonlinear system dynamics. The design principles are essentially based on Lyapunov's direct method. In this survey, we provide a comprehensive overview of Lyapunov-based nonlinear adaptive control techniques with simplified effective design examples, which are to be elaborated as related recent results are gradually shown. The scope of the survey contains research on singularity problems in adaptive control, the techniques to deal with linearly and nonlinearly parameterized uncertainties, robust neuro-adaptive control, and adaptive control methodologies combined with various nonlinear control techniques such as sliding-mode control, back-stepping, dynamic surface control, and optimal/$H_{\infty}$ control.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2001년도 ICCAS
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• pp.162.1-162
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• 2001

In this paper, the adaptive fuzzy system is used as an adaptive approximator for robot nonlinear dynamic. A theoretical justification for the adaptive approximator is proving that if the representive point(RP or switching function) and its derivative in sliding mode control are used as the inputs of the adaptive fuzzy system, the adaptive fuzzy system can approximate robot nonlinear dynamics in the neighborhood of the switching surface. Thus the fuzzy controller design is greatly simplified and at the same time, the fuzzy control rule can be obtained easily by the reaching condition. Based on this, a new method for designing an adaptive fuzzy control system based on sliding mode is proposed for the trajectory tracking control of a robot with unknown nonlinear dynamics.

• 대한환경공학회지
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• 제29권5호
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• pp.548-555
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• 2007

하폐수 처리에 대한 제어는 2가지의 장점을 가지고 있다. 유출수의 수질을 제어할 수 있다는 것과 하폐수 처리 비용의 절감이 그것이다. 본 연구의 목적은 부영양화의 원인물질로 잘 알려져 있는 암모니아성 질소를 제어함을 목적으로 한다. 제어는 간략화된 활성슬러지 모델 1(ASM No. 1)에 기초하고 있으며, 제어 방법은 다음과 같다. 우선, 유입수중 암모늄 농도를 측정하고, 간략화된 활성슬러지 모델 1(ASM No. 1)에 의하여 유출수 암모늄 농도가 1.0 mg/L가 아닐 경우 유출수의 암모늄 농도가 1.0 mg/L가 되도록 최적의 포기 시간을 산정하고 결정한다. 다음단계에서 유입수의 암모늄 농도를 교정한다. 이 과정은 계속적으로 반복되었다. 이와같은 방법에 의해 호기-무산소 조건을 반복하는 SBR 반응조가 한달간 제어되었다. 다음과 같은 결과를 얻을 수 있었다. 유출수의 암모늄 농도는 $0.22\sim3.1$ mg/L 범위를 순회하였으며, 유출수 암모늄 농도의 평균값은 1.1 mg/L이었다. 본 연구에서 사용된 Adaptive control 방법은 암모늄의 유출수 농도를 제어하고 예측하는데 매우 효과적이었다.

• Transactions on Control, Automation and Systems Engineering
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• 제3권4호
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• pp.262-267
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• 2001

Jeha Ryu Department of Mechatronics, Kwangju Institute of Science and Technology This paper presents an application of a robust adaptive control strategy to HexaSlide type six degrees-of-freedom parallel manipulators. The HexaSlide type parallel manipulators are characterized as an architecture with constant link lengths that are attached to moving sliders on the ground and to a mobile platform. The proposed control law is developed based on a simplified second order system dynamic equation in joint space with uncertain mass, damper, spring, and Coulomb friction terms. These uncertain parameters are updated by an adaptation law that is derived by Lyapunov stability theorem. A robust adaptive control law by using the boundary layer is designed for the purpose of compensating for the neglected dynamic effects of the mobile platform and the six moving links that are modeled as a disturbance term. Experimental results show good and fast tracking performance.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1992년도 하계학술대회 논문집 B
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• pp.1172-1175
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• 1992

The conventional adaptive hysteresis band current control technique has disadvantages such that on-line calculation of the hysteresis band is very complex, therefore, the adaptive hysteresis band must be stored in the look-up table. In this paper, a new simplified adaptive hysteresis band current control technique with phase decoupling is presented. The adaptive band is independent of the back EMFs. Using this adaptive band and the phase decoupled current error, the modulation frequency is fixed at nearly constant and the PWM inverter has optimal switching pattern.

• 대한환경공학회지
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• 제30권2호
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• pp.181-189
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• 2008

인은 자연계에서 부영양화 현상을 일으키는 주요한 인자로서 하수중의 인은 주로 인축적 미생물의 과잉섭취에 의해 제거된다. 이 연구의 목적은 인을 처리하는 하수처리공정을 제어하는 것이다. 이를 위해서 본 연구에서는 두가지의 제어방법을 응용하였으며 이 방법은 최적제어(Optimal control)와 적응제어(Adaptive control)이다. 우선 최적제어는 유입수중의 인농도를 측정한 이후에 간략화된 ASM No. 2 모델을 이용하여 유출수중의 인농도가 1.0 mg/L가 되는 포기시간을 산정하고 이 산정된 포기시간에 따라 반응조를 제어함으로써 이루어진다. 그런데 실제 반응조를 최적제어로 한 경우에도 실제 유출수중의 인농도는 1.0 mg/L가 되지 않는 경우가 발생한다. 이 때에는 적응제어로서 목표로 한 1.0 mg/L를 벗어난 만큼 목표농도를 변화시켜 주며 제어를 실시하였다. 약 한달간의 제어결과 유출수중의 인농도는 0.2$\sim$3.2 mg/L이었으며 평균은 1.0 mg/L로서 만족스러웠다. 연구수행중 하수처리공정에서 두 번에 걸쳐 인섭취가 제한되는 현상이 발생하였다. 이에 대한 원인을 규명한 결과 원인은 암모니아의 부족과 과다한 포기가 원인인 것으로 나타났다.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2001년도 ICCAS
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• pp.56.3-56
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• 2001

This study describes the jump error smoothing scheme with fuzzy logic based on the scalar adaptive filter. The scalar adaptive filter is an useful algorithm for smoothing abrupt jump errors. However, the performances of scalar adaptive algorithm depend on the variance of real signal. So to design an effective algorithm, many informations of real and jump signal are required. In this paper, the fuzzy rules are designed by the analysis of scalar adaptive filter, and then the improved and simplified scheme is developed for smoothing the jump error. Simulations to INS/GPS integrated system show that the proposed method is effective.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1993년도 한국자동제어학술회의논문집(국내학술편); Seoul National University, Seoul; 20-22 Oct. 1993
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• pp.8-13
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• 1993

This paper presents deterministic and adaptive control laws for two-link flexible arm. The flexible arm has considerable structural flexibility. Because of its flexbility, dynamic equations are very complex and difficult to get, dynamic equations for two-link flexible arm are derived from Bernoulli-Euler beam theory and Lagrangian equation. Using the fact that matrix is skew symmetric, controllers which have a simplified structure with less computational burden are proposed by using Lyapunov stability theory.

• International Journal of Fuzzy Logic and Intelligent Systems
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• 제12권1호
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• pp.47-52
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• 2012

This paper focuses on discrete-time sliding mode control with SIIM fuzzy adaptive switching gain. The adaptive switching gain is calculated using the simplified indirect inference fuzzy logic. Two fuzzy inputs are the normal distance from the present state trajectory to the switching function and the distance from the present state trajectory to the equilibrium state. The fuzzy output $f_{out}$(k) out f k is used to adjust the speed the adaptation law depending on the location of the state trajectory. The simulation results showed that the proposed method had no chattering in case of uncertain parameter without disturbance. Moreover the convergent rate of the switching gain was faster and more stable even in case of disturbance.