• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 2007.04a
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• pp.193-196
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• 2007

본 논문은 관측기 기반 시스템에 대한 강인 디지털 재설계 방안을 제안한다. 디지털 재설계란, 기존의 안정화된 연속시간 플랜트와 이산 시간에서 설계된 디지털 제어기와의 상태 접합 및 안정도 분석을 통해 전체 시스템을 재구성 하는 것을 말한다. 그리고 전 역적 접근을 위한 방안으로서 문제를 볼록 최적화 관점으로 변환 후, 에러가 가질 수 있는 놈의 영역을 최소화 하여 상태 접합을 이루고자 하였다. 본 논문에서는 관측기 기반 시스템에 대한 디지털 재설계를 목표로 하되, 추가적인 파라미터 불확실성을 고려한 강인 디지털 재설계를 구성하게 된다. 파라미터 불확실성은 이산화 과정에서 구조적 형태가 변화하기 때문에, 이를 고려하여 주어진 식을 선형 행렬 부등식 형태로 나타내게 된다. 이 조건들을 통해 디지털 재설계의 상태 접합 및 안정도가 유도 가능하다는 것을 본 논문에서 증명하게 된다.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.59 no.1
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• pp.70-75
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• 2010

The objective of this paper is to propose a new velocity measurement method for an electro-mechanical fin actuator. The model of the electro-mechanical fin actuator includes uncertainties such as unknown disturbances and parameter variations in flight condition. So, an electro-mechanical fin actuator system needs robust control algorithm which requires not only position information but also velocity information. Usually, analog tachometers have been used for velocity feedback in an electro-mechanical fin actuator. However, using these types of sensors have problems such as the cost, space, and malfunction. These problems lead to propose a new velocity measurement method using linear type Hall-effect sensor. In order to verify the proposed method, several experiments are performed using Model Following Sliding Mode Controller(MFSMC). It is shown that the MFSMC with a new velocity measurement method using linear type Hall-effect sensor can satisfy the requirements without using of velocity sensor.

• Journal of Institute of Control, Robotics and Systems
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• v.12 no.3
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• pp.233-240
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• 2006

This paper presents the robust control method using a self recurrent wavelet neural network (SRWNN) via adaptive backstepping design technique for stable walking of biped robots with unknown model uncertainties. The SRWNN, which has the properties such as fast convergence and simple structure, is used as the uncertainty observer of the biped robots. The adaptation laws for weights of the SRWNN and reconstruction error compensator are induced from the Lyapunov stability theorem, which are used for on-line controlling biped robots. Computer simulations of a five-link biped robot with unknown model uncertainties verify the validity of the proposed control system.

• Proceedings of the KIEE Conference
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• 2008.10b
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• pp.81-82
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• 2008

제어대상 시스템에 시간지연과 외란이 동시에 존재하는 경우, 스미스 예측기와 외란 관측기를 함께 사용하면 시간지연과 외란으로 인한 시스템의 성능저하를 완화할 수 있다. 또한 유동적인 시간지연에 대비하여 시간지연을 갖는 2차 시스템 모델링 기법으로 설계된 PID 제어기를 이용하면 시간지연에 대해 강인한 제어 시스템을 얻을 수 있다. 한편, 이전에 사용된 2차 시스템 모델링 기법의 적용범위가 한정되어 있어 이 방법은 적분 공정을 포함하는 시스템의 제어 문제에는 적용되지 못하였다. 본 논문에서는 적분공정을 포함하는 시스템에 적용될 수 있는 새로운 2차 시스템 모델링 기법의 PID 제어기를 통해 외란과 시간지연에 강인한 제어기 설계 기법을 제안한다. 모의실험을 통해 이전의 방법과 그 성능을 비교한다.

• Proceedings of the KIPE Conference
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• 2000.07a
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• pp.439-442
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• 2000

An adaptive nonlinear control of a brushless direct drive motor(BLDDM) is proposed. Comparing to the traditional PMSM the direct drive motor has smaller number of per pole and per phase slots to provide higher torque in low speed. This generic construction generates flux harmonics and finally results in unwanted torque harmonics. To control the speed a feedback linearization method is applied by choosing the $i_{ds}$ and $\omega_{m}$ as the output variables. The control of the flux harmonics is provided by using a flux observer with MRAC technique. As shown in the simula-tion results the proposed nonlinear speed controller has a good speed response in the steady state and robust to the flux variation

• Journal of Power Electronics
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• v.9 no.5
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• pp.791-799
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• 2009

This paper presents a time-varying sinusoidal disturbance compensation method (based on an adaptive estimation scheme) for induction motor drives fed by a matrix converter. In previous disturbance accommodation methods, sinusoidal disturbances with unknown time-invariant frequencies have been considered. However, in the new method proposed here, disturbances with unknown time-varying frequencies are considered. The disturbances can be estimated by using a disturbance accommodating observer, and an additional control input is added to the induction machine drive. The stability analysis is carried out considering the disturbance estimation error and simulation results are shown to illustrate the performance of the proposed solution.

• Journal of the Korean Society for Precision Engineering
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• v.16 no.2 s.95
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• pp.95-103
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• 1999

수중운동체가 수중에서 진행할 때 외부 파도에 의한 불확실한 부하 저항을 받으므로 이에 대응하는 핀(조타) 구동부의 제어 문제를 고려한다. 본 논문에서 제시하는 제어기는 본체로부터의 지정 각도를 부여 받으면 이에 부응하여 핀의 각도와 각속도를 이용하여 제어기의 알고리즘을 구축하여 지정된 경로를 추적하게 한다. 또한 핀의 각속도 정보의 이용이 부득이 어려운 상황에 대처하기 위하여 핀의 각도만을 이용한 출력제어기나 추정기를 설계하여 주위 환경의 불확실성을 극복할 수 있는 제어기를 제안한다. DC서보 모터로 구성괸 핀 구동부에 대해 실제 데이터를 사용하여 제안된 제어기의 성능을 시뮬레이션을 통하여 검증한다.

• The Journal of Korea Robotics Society
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• v.15 no.1
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• pp.77-89
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• 2020

This paper proposes a simple and intuitive model-free torque-tracking control for rotary electro-hydraulic actuators. The undesirable natural-velocity-feedback effect is discussed by introducing mechanical impedance into the electro-hydraulic actuation system. The proposed model-free torque control comprises inner- and outer-loop control to achieve two control objectives. Inner-loop control reduces the mechanical impedance passively and optimally. To improve the tracking accuracy, a certain form of proportional-integral-derivative control is applied to the outer loop. The robustness of the proposed closed-loop system against external disturbances is demonstrated by transforming the two-loop control structure into a disturbance observer form. The proposed method is validated on a single joint electro-hydraulic actuator.

• Proceedings of the KIPE Conference
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• 2004.07b
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• pp.738-741
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• 2004

The overall performance of AC servo system is greatly affected by the uncertainties of unpredictable mechanical parameter variations and external load disturbances. Therefore, to compensate this problem, it is necessary to know different parameters and load disturbances subjected to position/speed control. This paper proposes an online identification method of mechanical parameters/load disturbances for AC servo system using Support Vector Regression (SVR). The proposed methodology advocates analytic parameter regression directly from the training data, rather than adaptive controller and observer approaches commonly used in motion control applications. The experimental results demonstrate that the proposed SVR algorithm is appropriate for control of unknown servo systems even with large measurement noise.

• Proceedings of the KIEE Conference
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• 2005.07d
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• pp.2711-2713
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• 2005

This paper presents the tracking control method of robotic systems with uncertainties using self recurrent wavelet neural network (SRWNN) via the backstepping design technique. The SRWNN is used as the uncertainty observer of the robotic systems. The adaptation laws for weights of the robotic systems are induced from the Lyapunov stability theorem, which are used for on-line controlling robotic systems. Computer simulations of a three-link robot manipulator with uncertainties verify the validity of the proposed SRWNN controller.