• Journal of Astronomy and Space Sciences
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• v.11 no.2
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• pp.281-295
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• 1994

In this paper, the Variable Structure System(VSS) theory with new continuous switching dynamic equation is used to design an automatic controller for the active nutation damping in momentum bias stabilized spacecraft. In the application of VSS theory to a linearized multivariable system with the nutation damping systems, there exist some disadvantages such as how to determine the switching gains and how to reduce the chattering phenomina and reaching phase in input and state trajectories. To solve these drawbacks, this paper presents the continuous switching dynamic equation instead of the discontinuous switching logics to obtain the sliding mode. The new design approach is much simpler than the VSS theory. And there do not exist chattering phenomina in this method because the obtained control inputs are continuous. Simultaneously the reaching phase is reduced by a suitable choice of design factor.

• Journal of the Korean Institute of Intelligent Systems
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• v.14 no.4
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• pp.481-486
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• 2004

The biped robot has the better mobility than the conventional wheeled robot. Since a biped robot tends to tip over easily, it is necessary to take stability into account when determining a walking pattern. To ensure the dynamic stability of the biped robot, we have to adapt the ground conditions with a foot motion and maintain motion, and ensure its stability through the kinematics and dynamics analysis. But its mathematic model is not too easy. In this paper, in order to ensure the dynamic stability of a biped robot, we design the fuzzy model and confirm the realization possibility of the proposed method through some simulations.

• Journal of the Korean Institute of Intelligent Systems
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• v.8 no.2
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• pp.106-116
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• 1998

A position control algorithm of a flexible manipulator is studied. The proposed algorithm is based on an ACFAC(Automatic Constructed Fuzzy Adaptive Controller) system based on the neural network learning algorithms. The proposed system learns membership functions for input variables using unsupervised competitive learning algorithm and output information using supervised outstar learning algorithm. ACFAC does not need a dynamic modeling of the flexible manipulator. An ACFAC is designed that the end point of the flexible manipulator tracks the desired trajectory. The control input to the process is determined by error, velocity and variation of error. Simulation and experiment results show a robustness of ACFAC compared with the PID control and neural network algorithms.

• Journal of the Korean Institute of Telematics and Electronics
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• v.27 no.10
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• pp.53-59
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• 1990

In the control of robot manipulators, this paper presents a design of a new variable structure model following controller(VSMFC) using computed torque method (CTM). A sufficient condition for the existence of a sliding mode is derived by Lyapunov function. The reference model is a double integrators and the acceleration input consists of a proportional-derivative controller for the purpose of the stabilization of system and the desired performance. The proposed control scheme which consists of upper bounded and estimated value of each term of the manipulator of matrix inversion. Therefore the simulation results show that this controller is improved to the convergence of desired trajectories.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.40 no.7
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• pp.629-635
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• 2016

This paper presents a method for predicting and tracking the irregular motion of bio-systems, - such as petals of flowers, butterflies or seeds of dandelion - based on the particle filtering theory. In bio-inspired system design, the ability to predict the dynamic motion of particles through adequate, experimentally verified models is important. The modeling of petal particle systems falling in air was carried out using the Bayesian probability rule. The experimental results show that the suggested method has good predictive power in the case of random disturbances induced by the turbulence of air.

• The Bulletin of The Korean Astronomical Society
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• v.37 no.2
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• pp.214.1-214.1
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• 2012

한국천문연구원은 우주물체 전자광학 감시체계 기술개발 사업을 통해 자국위성의 추적감시를 위해 0.5m 광시야 감시관측소 국제 네트워크(OWL : Optical Wide-Field patroL)를 구축할 예정이다. OWL 시스템의 설계 검증을 위해 시험모델을 개발하였고, 연구소 내에 테스트베드에 설치하여 종합적인 테스트를 수행하고 있다. OWL 시험모델은 해외 설치모델과 동일하게 제작하였으며 돔을 제외한 모든 서브시스템을 국산화하였다. 유효구경 0.5m의 Richey-Cretian 형식의 광학계로 1.75도의 광시야를 구현하였고 영상보정을 위해 5개의 보정 렌즈를 사용하였다. 인공위성 추적을 위해 초당 10도 이상 기동이 가능한 alt-az 방식의 마운트를 개발하였다. 단일 노출에서 다수의 인공위성 궤적을 얻기 위해 chopper 제어 시스템을 도입하였고, chopper, 필터휠, de-rotator, CCD 카메라 등 4개의 부분품을 하나로 묶어 간결한 back-end를 구성하였다. 시스템의 안정성 향상과 유지보수의 용이성을 위해 망원경 및 관측소 제어 전용보드를 개발하였고, 전자동 무인관측을 위한 스케줄러 및 운영소프트웨어를 개발하였다. 시험모델을 이용하여 수 개월간 테스트을 수행하고, 관측결과 분석을 통하여 문제점을 수정보완한 후 OWL 시스템의 최종 설계안을 확정할 예정이다.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• v.9 no.1
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• pp.947-950
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• 2005

For revolving and elevating a turret of a tank, we substitute an existing oil pressure system with an electric system using a motor and applied the vector control method to this system. A switching method of an inverter for providing desired sinusoidal current to each phase of a motor, we adopted min-max pulse width modulation method which takes less computation time, rather than space vector pulse width modulation method. We designed a digital filter and applied it to the control system. Developed current controller is verified it's performance through a current control test, speed control test, frequency response and tracking a profile of speed test.

• Journal of the Korea Institute of Military Science and Technology
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• v.11 no.2
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• pp.23-31
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• 2008

The configuration model of a ballute type RAID(Ram Air Inflated Decelerator) for reducing the high speed and high revolution of smart submuntion is designed and tested. Three dimensional incompressible turbulent flow computational fluid dynamic analysis for the assembly of ballute and submunition is performed and pressure distribution, velocity, and drag around the assembly is calculated. Aerodynamic characteristics of the ballute assembly such as air flow inside and outside of the ballute and pressure distribution is clearly shown and it's drag coefficient is computed. Trajectory analysis of the submunition is performed and is in good agreement with the descending trajectory data of experimental model tested.

• Journal of Power System Engineering
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• v.7 no.4
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• pp.67-73
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• 2003

The entry guidance design involves trajectory optimization and generation of a drag acceleration profile as the satisfaction of trajectory conditions during the entry flight. The reference trajectory is parameterized and optimized as piecewise linear functions of the velocity. A regularization technique is employed to achieve desired properties of the optimal drag profile. The regularized problem has smoothness properties and the minimization of performance index then prevents the drag acceleration from varying too fast, thus eliminating discontinuities. This paper shows the trajectory control using the simple control law as well as the information of reference drag acceleration.

• Proceedings of the Korea Information Processing Society Conference
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• 2006.05a
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• pp.71-74
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• 2006

유비쿼터스 시대가 도래함에 따라 실내 환경에서의 위치 기반 서비스의 요구가 높아지고 중요해지고 있다. 따라서 본 논문은 실내 환경에서 이동객체의 위치를 추적하고, 이로 인해 생성된 위치데이터를 활용한 색인 알고리즘을 통해 이동 객체의 궤적을 트리에 저장, 색인하는 시스템을 제안한다. 제안하는 시스템은 기존에 사용되던 삼각측량 기법을 통해 실내 환경에서의 위치 데이터를 생성한 후, Kalman Filter를 사용하여 오차를 보정한다. 보정된 최종 위치 데이터를 기존에 연구된 HR 트리의 성능을 개선한 EHR-트리에 저장하여 이동객체의 위치를 색인 한다. 이를 통해 실내 환경에서 이동 객체의 이동 경로를 수집함으로 대형 쇼핑몰에서 미아를 찾거나 유통과 물류 등에서 사용자 또는 물품의 이동경로 분석을 통해 새로운 비즈니스 모델을 도입하는 등 다양한 서비스를 제공할 수 있다.