• Transactions of the Korean Society of Mechanical Engineers
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• v.11 no.5
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• pp.781-788
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• 1987

The state variables estimated in an observer were useed in feedback control of a hydraulic servosystem to increase the system stability and to enhance the system performance. The nonlinear hydraulic servosystem with the inherent nonlinearities due to the square root function of flow equation, the Coulomb friction and so on, was modelled as a fourth order linear hydraulic servosystem. Also, a second order linear system was derived for the observer-controller design. For these models, a fourth order linear observer and a second order linear observer were constructed respectively to evaluate the performance of the observer-based hydraulic servosystem. The results obtained from series of simulation showed that the system which had shown oscillatory phenomenon under proportional control became stable with the same maximum acceleration and velocity that it had started under proportional control.

• Proceedings of the KIEE Conference
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• 2002.11b
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• pp.290-292
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• 2002

전기철도 급전계통은 차량 또한 이동 부하이고, 비정상적인 전기적 특성이 나타날 수 있으므로, 전기적으로 정확한 해석을 할 필요가 있다. 본 연구는 PSCAD/EMTDC 과도해석 프로그램을 이용하여 직류 전기 철도 시스템을 모델링 함으로써 전기철도 급전계통의 정확한 특성을 연구하는 것이다. 한전 계통으로부터 전력을 급전 받아 전기철도차량 부하에 공급되는 급전계통을 실제와 가깝게 모델링 함으로써 정상상태 해석과 사고 시 과도특성 분석 및 계통에의 영향 해석을 목적으로 한다. 프로그램 특성상 각각의 소자를 모델링 한 후 4단자망 이론에 근거, 각 소자를 결합하여 전체 계통을 구성한다. 각각의 소자는 전차선로, 정류기 및 제어기를 포함한 차량부 (전동기, 제어소자), 정류 변전소 등으로 구성된다. 이 논문에서는 급전계통의 정상상태 및 고장전류를 분석함으로서 제안된 모델을 검증한다.

• Journal of Institute of Control, Robotics and Systems
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• v.14 no.3
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• pp.232-235
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• 2008

This paper presents an LMI-based method to design reduced order observers by which we can substitute full order sliding mode observers for a class of uncertain time-delay systems. We show that a reduced order observer can be constructed as long as the uncertain system satisfies the previous LMI existence conditions of a full order sliding mode observer. And we give explicit formulas of the reduced order observer gain matrices. Finally, we give a simple LMI-based design algorithm, together with a numerical design example.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.10 no.3
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• pp.467-472
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• 2006

This study has been done to design a precise system and develop position control algorithm to control a Composite Smoke Bomb Azimuth driving apparatus of a BLDC servo motor. Having to Blind the sight of opposite tank. the Smoke Bomb Rotational driving system needs instant response that is able to detect opponent appearance and blast the bomb at a short time. So a design that shows fast current response capability or $300[Hz]\sim500[Hz]$ is proposed. in the MIN-MAX PWM technology is used to increase the operational speed. in order to control the blasting position, a precision position control algorithm that utilizes the integral value of speed trajectory is suggested. Also these characteristics are monitored and assessed by the PC based monitoring program which shows the graphs of current, voltage, position, and speed parameters. The main controller is based on a TMS320VC33 high performance floating-point DSP(Digital Signal Process) and the PWM generator utilizes EPM7128 CPLD.

• Journal of Korea Society of Industrial Information Systems
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• v.5 no.1
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• pp.31-36
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• 2000

This paper presents a design method of deadbeat controller for DC motor driving a rotational system with gear. The deadbeat-response design developed for control system of a sampled continuous-data process does not guarantee zero intersampling ripples, but the proposed deadbeat control system that consists of the integral controller and the full-order state observer, and zero-order hold using in continuous systems, has many advantages such as an output response without the ripples and reaching the steady state without error after a given sampling period and faster settling time than the optimal control system in the same sampling period. The results of a case study through matlab simulation are shown that the efficiency of the proposed controller for DC motor driving a rotational system with gear is verified by comparing with optimal controller etc.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.7 no.4
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• pp.575-579
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• 2006

In this paper, an instantaneous speed observer with a reduced order is proposed to implement an indirect control for a motor with excellent dynamic stability and performance in a very low speed region. The proposed observer can estimate the instantaneous speed in very low speed region and simplify the system configuration by adopting an least order load torque-inertia observer to estimate the load torque and the motor speed. Simulation are carried out to illustrate the performance of the proposed estimator at very low speed.

• Proceedings of the KIEE Conference
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• 2000.07d
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• pp.2452-2454
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• 2000

현재, 전차선의 트롤리선을 설치하는 것은 수작업에 의해 행해지고 있어 작업의 효율화와 함께 최적의 장력제어가 필요하다. 케이블을 새롭게 가설하는 장치는 케이블을 릴에 감아 올릴 필요성은 거의 없기 때문에 케이블을 풀어주는 속도와 로드셀에 의해 장력을 검출하고 장력을 발생하는 하드웨어 구성방법을 연구하는 것이다 본 연구는 현수형 케이블(Catenary Cable)의 동적 모델링을 작성한다. 이 시스템에 대하여 교류서보 전동기를 이용한 장력 발생장치를 모델링한다. 현수형 시스템의 장력계측 장치는 하중변환기(load cell)를 사용하고 수학적 모델링을 행한다. 장력계측 장치에 관해서 스프링 저울을 이용해 출력을 비교 검토한 결과, 인장력을 계측하는 장치로서의 유효성을 확인하였다.

• Journal of Institute of Control, Robotics and Systems
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• v.7 no.7
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• pp.614-621
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• 2001

The controllers for a full car 7-DOF model with 4 active or semi-active suspension units are designed and evaluated in this research. The control algorithms for suspension systems, such as full state feedback active, full state feedback semi-active, sky-hook active, sky-hook semi-actvie, and on-off suspension systems, are analyzed and evaluated with respect to ride comfort. The vehicle dynamic performances are expressed by response curves to a bump input, performance indices for asphalt road input, and frequency characteristic curves. Heaving, rolling, and pitching inputs are applied to the vehicle dynamic system to evaluate frequency characteristics. The simulation results show that the ride quality of the sky-hook controller approaches that the full state feedback controller more closely in semi-active suspension system than in active suspension system. For the implementation of a vehicle with sky-hook suspension control systems in this paper, 7 velocity sensors are required to measure the states.

• The Transactions of the Korean Institute of Power Electronics
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• v.18 no.6
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• pp.565-572
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• 2013

The sensorless speed control using the improved full-order flux observer for PMSM is proposed in this paper. A conventional full-order flux observer has a drawback that the estimated flux of this observer contains the ripple component at the low speed range due to the increased gains of the convectional full-order flux observer. The improved full-order flux observer with the modified gains guarantee the improved estimation performance without ripple component at the from zero to high speed range. To identify the performance of proposed observer, the simulation and experiment are conducted and this performance is compared with the conventional full-order observer.

• Proceedings of the KIPE Conference
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• 2010.11a
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• pp.286-287
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• 2010

계통연계 인버터 제어 시 계통 전압과 동상인 전류를 공급해 주기 위해 반드시 계통 전압의 위상 정보가 필요하다. 기존의 PLL 방법은 계통 전압에 고조파가 존재하지 않을 시에 검출된 위상 값은 정확하지만, 고조파 존재 시 정확한 위상 값을 얻을수 없다. 본 논문에서는 전차원 상태 관측기를 이용하여 기본파 성분과 고조파 성분을 분리하여 검출된 위상의 정상상태 오차를 감소시킬 수 있고, 저역통과필터를 고려한 PLL 시스템의 모델링을 이용하여 동특성을 개선하는 방법을 제안하였다. 이를 모의실험을 통하여 검증하였다.