• 대한전기학회:학술대회논문집
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• 대한전기학회 1998년도 하계학술대회 논문집 C
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• pp.982-984
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• 1998

In this paper, a stability proof of the closed-loop stability for the nonlinear feedback linearization-$H_\infty$/sliding mode controller (NFL-$H_\infty$/SMC) is done by a Lyapunov function candidate using an addition form of the sliding surface vector and the estimation error.

• Kyungpook Mathematical Journal
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• 제61권2호
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• pp.353-369
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• 2021

In this paper, we examine and analyze the concept of different non-integer chaotic systems with external disturbances, uncertainties, and input non-linearities. We consider both drive and response systems with external bounded disturbances and uncertainties. We also consider non-linear control inputs. For synchronization, we introduce the adaptive sliding mode technique, in which we establish the stability of the controlled system by a control which estimates uncertainties and disturbances, and then applies a suitable sliding surface to control them. We use computer simulations to established the efficacy and adeptness of the prospective scheme.

• 한국재료학회지
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• 제17권11호
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• pp.569-573
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• 2007

The static and dynamic hydrophobicities of the water droplets placed on a hydrophobic surface coated using a fluoroalkylsilanes monolayer with different molecular chain lengths were investigated through direct observation of the actual droplet motion during the sliding process. The surface roughness of both was found to be less than 1 nm. The static contact angles of the coated FAS-3 and FAS-17 were respectively $80^{\circ}$ and $108^{\circ}$ at $150^{\circ}C$, 1 h. The slope of sliding acceleration against the water droplet mass exhibited an inflection point, thus suggesting the switching of the dominant sliding mode from slipping to rolling. While their sliding angles were similar in value, notable differences were exhibited in terms of their sliding behavior. This can be understood as being due to the contribution of the shear stress difference at the interface between the solid surface and water during the sliding process. These results show that the sliding acceleration of the water droplets depends strongly on the balance between gravitational and retentive forces on the hydrophobic surface.

• Structural Engineering and Mechanics
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• 제23권3호
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• pp.293-308
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• 2006

This paper presents a complete and consistent formulation to study the seismic response of a free-standing ship supported by an arrangement of n keel blocks which are all located in a dry dock. It is considered that the foundation of the system is subjected to both horizontal and vertical in plane excitation. The motion of the system is classified in eight different modes which are Rest (relative), Sliding of keel blocks, Rocking of keel blocks, Sliding of the ship, Sliding of both keel blocks and the ship, Sliding and rocking of keel blocks, Rocking of keel blocks with sliding of the ship, and finally Sliding and rocking of keel blocks accompanied with sliding of the ship. For each mode of motion the governing equations are derived, and transition conditions between different modes are also defined. This formulation is based on a number of fundamental assumptions which are 2D idealization for motion of the system, considering keel blocks as the rigid ones and the ship as a massive rigid block too, allowing the similar motion for all keel blocks, and supposing frictional nature for transmitted forces between contacted parts. Also, the rocking of the ship is not likely to take place, and the complete ship separation from keel blocks or separation of keel blocks from the base is considered as one of the failure mode in the system. The formulation presented in this paper can be used in its entirety or in part, and they are suitable for investigation of generalized response using suitable analytical, or conducting a time-history sensitivity analysis.

• International Journal of Aeronautical and Space Sciences
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• 제7권1호
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• pp.65-72
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• 2006

A variable structure controller with an optimized sliding surface is proposed for slew maneuver of a rigid spacecraft. Rodrigues parameters are chosen to represent the spacecraft attitude. The quadratic type of performance index is used to design the sling surface. For optimization of the sliding surface, a Hamilton- Jacobi-Bellman equation is formulated and it is solved through the numerical algorithm using Galerkin approximation. The solution denotes a nonlinear sliding surface, on which the trajectory of the system satisfies the optimality condition approximately. Simulation result demonstrates that the proposed controller is effectively applied to the slew maneuver of a rigid spacecraft.

• 한국지능시스템학회논문지
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• 제11권4호
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• pp.347-353
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• 2001

본 논문은 기존의 시간 지연 제어 기법을 이용하여 TSK 모델 퍼지 제어 시스템의 안정화에 적용하는 방법을 제시한다. TSK 모델 퍼지 시스템이 기존의 PDC 방법에 의하여 안정화되어지는 경우 발생하게 되는 LMI 문제를 피하기 위하여 시간 지연 방법에 의한 새로운 안정화 조건이 다루어진다. 제시되어진 방법은 mass-spring-damper 시스템에 적용되어 적용가능성이 평가된다.

• 제어로봇시스템학회논문지
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• 제9권11호
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• pp.861-867
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• 2003

We propose a sliding surface design method for linear systems with mismatched uncertainties in the state space model. In terms of LMIs, we derive a necessary and sufficient condition for the existence of a linear sliding surface such that the reduced-order equivalent sliding mode dynamics restricted to the linear sliding surface is not only stable but completely invariant to mismatched uncertainties. We give an explicit formula of all such linear switching surfaces in terms of solution matrices to the LMI existence condition. We also give a switching feedback control law, together with a design algorithm. Additionally, we give some hints for designing linear switching surfaces guaranteeing pole clustering constraints or linear quadratic performance bound constraints. Finally, we give a design example in order to show the effectiveness of the proposed methodology.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2008년도 학술대회 논문집 정보 및 제어부문
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• pp.435-436
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• 2008

본 논문에서는 궤적이 슬라이딩 평면 밖에 있는 경우에 대해서도 LQ 성능을 보장하는 최적 슬라이딩 모드 제어기 설계 방법을 제안한다. 본 논문에서 제안한 방법에서는 슬라이딩 평면상에 있을 경우뿐만 아니라 슬라이딩 평면 밖에서도 LQ 성능을 보장하기 위해 최적 슬라이딩 평면을 이용하며 제어기에 슬라이딩 변수에 선형적으로 의존하는 항을 추가한다. 또한 제어기의 강인성을 위해 본 논문에서 제안된 새로운 외란 추정기법을 제어기와 결합한다. 마지막으로 컴퓨터 모의 실험을 통해 본 논문에서 제안한 제어기 설계 방법의 효율성을 검증하고자 한다.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2003년도 춘계학술대회 논문집
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• pp.373-377
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• 2003

Recently, advanced manufacturing systems with high speed and intelligence have been developed for the betterment of machining ability. In this case, reliability prediction work with motion characteristic evaluation of sliding cover(C-plate, Bellows, etc) has also important role from design procedure to manufacturing and assembly process. Accordingly in this study, H/W test-bed system for reliability evaluation of sliding cover has been developed to obtain proper reference data for design of new model, prevention trouble (failure mode), and improvement of quality and lift cycle extremely for advanced mother machinery.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2007년도 제38회 하계학술대회
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• pp.1587-1588
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• 2007

IPM(Interior Permanent Magnet) Machine의 전류 제어는 자기저항에 의존하는 토크특성 때문에 SPM(Surface Permanent Ma- gnet) Machine보다 복잡하다. 고성능 토크제어를 위해서는 d축 전류와 q축 전류의 동특성간의 상태 decoupling이 요구된다. 그러나 전류의 상태 동특성이 coupling된 인덕턴스의 변화(온도, 파라미터들의 부정확한 측정값)는 상태 decoupling을 어렵게 한다. 그래서 이러한 변화와 각각의 전류가 독립적으로 제어될 수 있게 여러 decoupling 방법들에 초점이 맞춰지고있다. 본 연구는 외란에 강하고, 특히 인덕턴스의 변화와 상관없는 이상적인 토크제어를 하기 위해 신경회로망을 이용하여 슬라이딩 평면(sliding surface)을 구성하고, SMC(Sliding Mode Control)를 이용하여 상태 cross-coupling의 decoupling을 위한 새로운 접근을 제안한다. 이 방법은 PI제어 성능과 SMC의 강인성을 알고리즘을 이용하여 결합한 것이라고 볼 수도 있다.