• Journal of IKEEE
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• v.9 no.1 s.16
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• pp.47-56
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• 2005

A new improved robust variable structure tracking controller is presented to provide an accurately prescribed tracking performance for brushless direct drive(BLDD) servo motors(SM) under uncertainties and load variations. A special integral sliding surface suggested for removing the reaching phase problems can define its ideal sliding mode and virtual ideal sliding trajectory from an initial position of SM. The tracking error caused by the nonzero value of the sliding surface is derived. A corresponding continuous control input with the disturbance observer is suggested to track a predetermined virtual ideal sliding trajectory within a prescribed value under all the uncertainties and load variations. The usefulness of the proposed algorithm is demonstrated through the comparative simulations for a BLDD SM under load variations.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.26 no.2
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• pp.243-253
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• 2002

This paper presents the system modeling, analysis, and controller design and implementation for a rotational inverted pendulum system(RIPS), which is an under-actuated system and has the problem of unattainable angular velocity state. A sliding mode controller using the parameterization of both the hyperplane and the compensator fur output feedback is applied to the RIPS. Also, to improve the performance of the control system, a disturbance observer which estimates the disturbance, parameter variation, and some modeling errors of RIPS with less computational effort is used together. The results of simulation and experiment show that the proposed control system has superior performance for disturbance rejection and regulation at certain initial conditions.

• Proceedings of the KIEE Conference
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• 2011.07a
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• pp.1145-1146
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• 2011

최근에 영구자석 동기전동기의 구동방식에서 회전자의 위치 및 속도 검출기가 없는 센서리스 방식이 많이 연구되고 있다. 대부분의 센서리스제어 방식에서 위치 및 속도추정은 전동기 전압방정식으로부터 계산된다. 따라서 파라미터 오차는 센서리스 제어성능에 큰 영향을 미치게 된다. 본 연구는 파라미터 보정에 의한 영구자석 동기전동기의 센서리스 제어 성능 개선에 관한 연구로서 파라미터 보상을 가지는 슬라이딩 모도 관측기를 제안하고 종래의 방식과 비교하여 본 연구에서 제안한 방식을 검증한다.

• Journal of the Korea Institute of Military Science and Technology
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• v.8 no.3 s.22
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• pp.92-100
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• 2005

The objective of this paper is to design a sliding mode controller of an electro-mechanical fin actuation system using extended reducer-observer(ERO) which is used in order to estimate the velocity. The employed observer enables proper estimation of the plant state variables, even in the case of the constant or slow varying load torque disturbances. The effectiveness of this control scheme is verified by comparison with a PID control through a series of simulation studies. The simulation results show that the sliding mode control designed with the ERO gives good control performances.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.41 no.7
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• pp.591-597
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• 2017

This study is to develop a vehicle Integrated Dynamics Control System(IDCB) that can stabilize the lateral dynamics and maintain steerability. To accomplish this task, an eight degree of freedom vehicle model and a nonlinear observer are designed. The IDCB independently controls the brake systems of four wheels with a fuzzy logic control and a sliding model control. The result shows that the nonlinear observer produced satisfactory results. IDCB tracked the reference yaw rate and reduced the body slip angle under all tested conditions. It indicates that the IDCB enhanced lateral stability and preserved steerability.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.54 no.1
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• pp.40-46
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• 2005

This paper has investigated the speed sensorless indirect vectorcontrol of a two-phase induction motor to implement adjustable-speed drive for low-power applications. The sliding mode observer estimates rotor speed. The convergence of the nonlinear time-varying observer along with the asymptotic stability of the controller has been analyzed. To define the control action which maintains the motion on the sliding manifold, an "equivalent control" concept is used. It has been simulated and implemented on a sensorless indirect vector drive for 150W two-phase induction motor. The simulation and experimental results demonstrate effectiveness of the estimation method.

• Journal of the Korean Society for Precision Engineering
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• v.23 no.4 s.181
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• pp.44-51
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• 2006

This paper addresses sliding mode control of the anti-lock braking system (ABS) with a disturbance observer for model uncertainties such as vehicle parameter variation, un-modeled dynamics, and external disturbances. By using a nominal vehicle model, a sliding mode controller is designed to achieve a desired wheel slip ratio for ABS control. To compensate the model uncertainties, a disturbance observer is introduced with the help of a transfer function of a hydraulic brake dynamics. A proposed sliding mode controller with a disturbance observer is evaluated through simulations for model uncertainties. The simulation results show that the disturbance observer can enhance performances of sliding mode control for ABS.

• Proceedings of the KIPE Conference
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• 2010.07a
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• pp.526-527
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• 2010

본 논문에서는 슬라이딩 모드 관측기를 이용하여 IPMSM(Interior Permanent Magnet Synchronous Motor)의 센서리스 제어의 기동특성에 관한 연구를 수행하였다. IPMSM의 센서리스 제어는 초기 구동시 회전자의 위치를 알 수가 없으므로 Open-Loop알고리즘을 이용하여 강제로 모터를 구동시킨다. 그러므로 Open-Loop에서 Closed-Loop로 제어되는 시점에서 부하의 상태에 따라 기동 특성에 문제점을 야기 시킬 수 있다. 본 논문에서는 부하에 따라 기동 특성에서 야기되는 문제점과 해결책을 제시한다. 제시된 방법을 시뮬레이션을 통해 검증한다.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2004.05a
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• pp.304-304
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• 2004

오피스용 3차원 실물 복제기는 개발자에게 좀 더 라르고 효율적인 작업 환경을 구현해 줌으로 해서 산업 전반에 많은 영향을 주게 될 것이다. 기존의 오피스용 3차원 실물 복제기는 가격이 고가여서 실제적으로 일반 사무용으로 사용되기는 어려웠다. 하지만 저 가격의 고속 고 정밀 오피스용 3차원 실물 복제기가 국내 기술에 의해 개발된다면 시장변화에 민감한 제품의 개발이나 최근 빨라진 제품의 생산 주기에 효율적으로 대처 할 수 있을 것이다. 이러한 오피스용 3차원 실물 복제기는 무엇보다도 기존의 국외 오피스용 3차원 실물 복제기 보다 저 띠용이어야 하며 고속의 성능을 가지고 있어야 한다.(중략)

• Journal of Ocean Engineering and Technology
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• v.20 no.6 s.73
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• pp.24-34
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• 2006

Hydrodynamic coefficients strongly affect the dynamic performance of an AUV. Thus, it is important to know the true values of these coefficients, in order to accurately simulate the AUV's dynamic performance. Although these coefficients are generally obtained experimentally, such as through the PMM test, the measured values are not completely reliable because of experimental difficulties and errors. Another approach, by which these coefficients can be obtained, is the observer method, in which a model-based estimation algorithm estimates the coefficients. In this paper, the hydrodynamic coefficients are estimated using two nonlinear observers: a sliding mode observer and an extended Kalman filter. Their performances are evaluated in Matlab simulations, by comparing the estimated coefficients obtained from the two observer methods, with the experimental values as determined from the PMM test. A sliding mode controller is constructed for the diving and steering maneuver by using the estimated coefficients. It is demonstrated that the controller, applied with the estimated values, maintains the desired depth and path with sufficient accuracy.