• Proceedings of the KIEE Conference
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• 2005.10b
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• pp.340-342
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• 2005

This paper describes the speed-sensorless vector control system of a three-phase induction motor using sliding mode flux/speed observer. The sliding mode observer estimates the rotor speed. The error between the actual and observed currents converges to zero which guarantees the accuracy of the flux observer. The convergence of nonlinear time-varying observer along with the asymptotic stability of the controller was analyzed. To define the control action which maintains the motion on the sliding manifold, an "equivalent control" concept was used. It was simulated and implemented on a sensorless indirect vector drive for 750[W] three-phase induction motor. The simulation and experimental results demonstrated the effectiveness of the proposed estimation method.

• Proceedings of the KIEE Conference
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• 2004.07d
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• pp.2236-2238
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• 2004

This paper proposes the self-recurrent wavelet neural network (SRWNN) observer based sliding mode control (SMC) method for nonlinear systems. Unlike the classical SMC, we assume that all states of nonlinear systems are not measured and design the SRWNN observer to measure the states of nonlinear systems. The SRWNN in the observer is used for approximating the observer system's gain. To generate the control input for controlling the nonlinear system, the measured states are used. The sliding surface with a boundary layer is defined to remove the chattering of the control input. Simulation result to show the effectiveness of the SRWNN observer is presented.

• Proceedings of the KIEE Conference
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• 2009.04a
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• pp.74-76
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• 2009

In this paper, search method and sliding mode observer are developed for efficiency optimization of induction motor. The proposed control scheme consists of efficiency controller and adaptive backstepping controller. A search controller for which information of input of fuzzy controller is included in efficiency controller that uses a direct vector controlled induction motor. The search controller is based on the "Rosenbrock" method and finds the flux level at the minimum input power of induction motor. Once this optimal flux level has been determined, this information is utilized to update the rule base of a fuzzy controller A sliding mode observer is designed to estimate rotor flux and an adaptive backstepping controller is also used to compensate for mechanical uncertainties in the speed control of induction motor. Simulation results are presented to validate the proposed controller.

• Journal of Institute of Control, Robotics and Systems
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• v.5 no.2
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• pp.151-157
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• 1999

In this paper, an integrated nonlinear sliding mode observer and controller has been designed in order to control of an automotive engine idle speed. The primary objective of the engine idle speed control is to maintain the desired engine idle speed despite of various torque disturbances via estimating air mass flow at the location of the injector in intake manifold by using a sliding mode observer. Simulation results show that the case where both throttle angle and ignition time are used as control inputs outperforms the case where just only throttle angle is used as a control input.

• The Bulletin of The Korean Astronomical Society
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• v.37 no.1
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• pp.102-102
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• 2012

타이탄의 근적외선 영역 스펙트럼에서 나타나는 특유의 넓은 흡수밴드를 고체 탄화수소화합물과 질소화합물의 조합으로 설명하고자 한다. 이 흡수 밴드는 대기권의 하층부에 존재하는 연무(haze)에 의한 것으로, 3.3 - 3.4 micron 부근과 2.30 - 2.35 micron 부근에서 유사한 형태가 발견됐다. 두 파장대 모두 C-H 스트레칭 모드가 존재하는 영역이라는 공통점이 있으며, 그 형태가 넓은 흡수밴드로 나타나므로 대기 중에 고체상태의 탄화수소화합물이 존재하는 것으로 유추할 수 있으며, 관련 분자들의 실험값과 복사전달모델을 이용하여 이를 설명하고자 한다. 또한, 이 흡수밴드는 고도에 따라 그 형태와 세기가 달라지므로, 연무 입자들의 고도에 따른 수직분포 및 크기 등을 파악할 수 있다. 이 연구에서는 기존에 타이탄에서 발견된 $CH_4$, $C_2H_6$, $CH_3CN$의 고체 분광선과, 해당 영역에서 흡수선을 보이는 $C_5H_{12}$, $C_6H_{12}$, $C_6H_{14}$ 등의 고체 분광선을 이용한 모델을 Cassini 탐사선의 VIMS 관측자료로부터 유도한 파장 및 고도에 따른 광학적 깊이 변화량과 비교하여 보여주고자 한다.

• Proceedings of the KSME Conference
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• 2001.11a
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• pp.562-567
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• 2001

The number of required modes to provide accurate force information in a truncated model of a flexible structure is investigated. In the case of modal truncation of a distributed parameter system, the difference in convergence rates between displacements and forces is discussed. The residual flexibility, a term from past literature, is used to recapture some of the lost force information in a truncated model. This paper presents numerical and experimental results of a study where the residual flexibility is used in conjunction with a Kalman filter so that accurate force information may be obtained from a small set of displacement measurements with a reduced-order model. The motivation for this paper is to be able to obtain accurate information about unmeasurable dynamic reaction forces in a rotating machine for diagnostic and control purposes.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2001.04a
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• pp.186-189
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• 2001

In a precise control system, the Lu-Gre friction model has often been used to describe the nonlinear friction. For the XY table system with this friction model, we identified the friction parameters and designed nonlinear observer. The nonlinear friction effects could be removed within appropriate position tracking errors and control inputs through experiments. Also, we designed the nonmodel-based SMC system to compensate the nonlinear friction. Through experiments, it is shown that this method has the similar performance compared with the nonlinear observer system and is useful when friction parameters are hard to identify except the problem of input chattering.

• Proceedings of the Korean Society of Marine Engineers Conference
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• 2006.06a
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• pp.277-278
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• 2006

This paper presents circuit models and control algorithms of distributed generation system(DGS) which consists of Z-type converter and PWM inverter Z-type converter which employs both the L and C passive components and shoot-through zero vectors instead of the conventional DC/DC converter in order to step up DC-link voltage. Discrete time sliding mode control with the asymptotic observer is used for current control.

• Journal of Institute of Control, Robotics and Systems
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• v.3 no.1
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• pp.40-45
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• 1997

A robust disturbance rejection controller for the hovering motion of underwater vehicles in near the surface of sea is presented. The suggested controller consists of two control parts, the one is disturbance observer for taking into account the effects of sea wave and missile-launching forces, and the other is sliding mode controller for the robust stability of underwater vehicles with model uncertainties and nonlinearities. It is shown that the sliding mode control system with disturbance observer is more effective compared with the sliding mode control system, especially in case that large sea wave force is affected.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2004.05a
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• pp.233-236
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• 2004

In this paper, a new sensorless vibration control scheme is proposed for a flexible manipulator system. A robust sliding mode controller incorporating with a ‘reaction moment observer’ used for the estimation of the reaction moment reciprocally acting on flexible arm and hub inertia is introduced to achieve desired control target. The rigid body dynamics of the single-link flexible manipulator is simply considered in the design of the sliding mode controller. Then, the reaction moment is estimated by the proposed reaction moment observer to suppress the residual vibration of the flexible arm. The performance of the proposed control scheme is verified by computer simulation and experiment.