• Proceedings of the Korean Society of Precision Engineering Conference
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• 1995.10a
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• pp.606-609
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• 1995

To stabilize a satellite, a spin stabilization method is used for attitude control. The spin stabilization uses the centrifugal force of a pendulum damper which is tilted long boom, to stabilize the unstable satellite. In this paper, an inverted pendulum system is implemented which is similar to the spin stabilization method. Study on the velocity of the rotation axis and the inverted pendulum's angle stability is shown. We designed a controller using a 32bit TMS320C31 DSP for the CPU and also performances by PLD control and Sliding Mode Control is compared.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.11 no.1
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• pp.26-31
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• 1975

Mordern Ocean-going ships utilize stabilization techniques in order to minimize the effects of oscillations due to the unwanted disturbances. In this paper, as an elementary design of automatic control system with linear-state vari;tble feedback and series compensator for ship stabilization, analysis and design is limited to the linear time-invariant single input and output system. In order for the Controlled system to meet the requirements of stability, accuracy and transient response, a model of the automatic control system is proposed. For the analysis and design of this model, the state-space method, that is, the mordern way, or an alternative to the transfer function method of describing a linear system that utilize the state variables and state equations, is applied.

• The Transactions of the Korean Institute of Electrical Engineers D
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• v.55 no.5
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• pp.226-228
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• 2006

This paper deals with a linear matrix inequality (LMI) approach to the design of a static output feedback controller that simultaneously stabilizes a finite collection of linear time-invariant plants. Simultaneous stabilization by static ouput feedback is represented in terms of LMIs with a rank condition. An iterative penalty method is proposed to solve the rank-constrained LMI problem. Numerical experiments show the effectiveness of the proposed algorithm.

• 제어로봇시스템학회:학술대회논문집
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• 2000.10a
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• pp.371-371
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• 2000

A strategy for the swing-up control according to states of the 2-link rotational pendulum is proposed. The proposed controller consists of two modes of control such as divergence mode and stabilization mode. When the controller is in divergence mode, control input is generated using sinusoidal and signum function to make the first and second links reach the bottom and top positions, respectively. After the controller finishes divergence mode, stabilization mode is initiated to keep the pendulum around the top position using pole-placement method. Dynamic models including actuator dynamics are obtained using coordinate changes at each control mode. Simulation results are given to show the effectiveness of the proposed method.

• 한국정보디스플레이학회:학술대회논문집
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• 2005.07a
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• pp.437-438
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• 2005

A polymer stabilization method is employed to reduce the transition time from field-induced homeotropic(H) state to reflecting planar(P) state in the cholesteric liquid crystal(ChLC) display. To stabilize ChLC by polymer, we mixed ChLC with diacrylate of 2 $wt%{\sim}6$ wt%. Two samples were made with different method of stabilization. For one sample the diacrylate of 2 wt% was polymerized with the ChLC in P state, while for the other sample diacrylate of 16 wt% was polymerized with ChLC in H state. In the former case, the transition time was 1000 times faster then those in the pure sample. In the latter sample, the transition time was 1700 times faster than those in pure ChLC sample.

• The Transactions of the Korean Institute of Electrical Engineers D
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• v.54 no.4
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• pp.215-219
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• 2005

This paper aims at asymptotic stabilization for uncertain dynamic systems with state and input delays. We propose a memoryless state feedback controller which maximizes the delay bound for guaranteeing stability of the system. Using Lyapunov method and linear matrix inequality (LMI) approach, a delay-dependent stabilization criterion is devised by taking the relationship between the terms in the Leibniz-Newton formula into account. The criterion is represented in terms of LMIs, which can be solved by various efficient convex optimization algorithms. Numerical examples are given to illustrate our main method.

• Journal of Institute of Control, Robotics and Systems
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• v.12 no.8
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• pp.810-817
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• 2006

This paper presents a rotational motion estimation and correction technique for digital image stabilization. An equivalent rotation model is derived so as to accommodate a combined rotational and the translational motion. Thanks to this simplification, the suggested estimation algorithm can directly find the rotational center using geometric characteristic of local motion vectors instead of using searching method. And we also present recursive version of frame to reference algorithm(FRA) for the real time implementation. The proposed DIS system does not require time consuming parameter searching process, while showing comparatively good performance compared with the previous ones. To show the effectiveness of the DIS scheme, the algorithm has been implemented on the DSP based hardware system and experimental results are also discussed.

• Proceedings of the Korean Geotechical Society Conference
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• 2002.10a
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• pp.529-536
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• 2002

The purpose of this paper os to present and discuss some of flow and drain observed in modelling results. Because dredged fill ground of Yul-Chon located in the south coast of Korea is very soft, this ground should be improved after operation of surface stabilization. There are surface stabilization method such as chemical stabilization, desiccation, horizontally vacuum drain, replacement, and geosynthetics. In Yul-Chon, PTM(Progressive Trenching Method) is adopted to provide the necessity condition of surface desiccation. In the case trench in the dredged soft ground is formed by PTM equipment, pore water in the ground is drained through trench. There, drain and desiccation of surface ground increase, and bearing capacity is improved. In this research, when trench in the dredged soft ground is formed by PTM equipment, permeable characteristics and drain efficiency of pore-water are analyzed using SEEP/W software package. Results show variation of total head, pressure head, flux, hydraulic gradient, and flow quantity.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.34 no.6
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• pp.213-219
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• 1985

Superconducting Magnetic Energy Storage (SMES) system can be used for power system stabilization by absorbing or discharging active and reactive power through thyristor-comtrolled converters. In this paper, we have proposed a control algorithm that the active and reactive powers of SMES are simultaneously controlled to increase power system dynamic stability. The proposed method was applied to one machine-infinite and three machines and three load model systems. And it has been shown that the proposed algorithm is more effective in power system stabilization than the conventional one that only the active power of SMES is controlled. Eigenvalue sensitivity analysis method is introduced to estimate the optimal location of SMES in the sense of the power system oscillation mode.

• The Journal of Korea Robotics Society
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• v.5 no.2
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• pp.85-92
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• 2010

In this paper, we propose a digital image stabilization technique using edge detection and Lucas-Kanade optical flow in order to minimize the motion of the shaken image. The accuracy of motion estimation based on block matching technique depends on the size of search window, which results in long calculation time. Therefore it is not applicable to real-time system. In addition, since the size of vector depends on that of block, it is difficult to estimate the motion which is bigger than the block size. The proposed method extracts the trust region using edge detection, to estimate the motion of some critical points in trust region based on Lucas-Kanade optical flow algorithm. The experimental results show that the proposed method stabilizes the shaking of motion image effectively in real time.