• 제어로봇시스템학회:학술대회논문집
• /
• 제어로봇시스템학회 1997년도 한국자동제어학술회의논문집; 한국전력공사 서울연수원; 17-18 Oct. 1997
• /
• pp.199-202
• /
• 1997

In this paper, a novel disturbance observer is proposed in order to regulate the disturbance in motor systems. The proposed observer does not require the implementation of ideal derivative of the state since the inverse of the nominal model is not used in the design of the observer. The transfer gain from a disturbance to the output of the disturbance observer is one. So, there is no time-delay in the response due to the dynamics of the observer.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2004년도 학술대회 논문집 정보 및 제어부문
• /
• pp.705-707
• /
• 2004

In this paper, we propose a robust control technique against parameter uncertainties as well as external disturbances. It is robust control scheme using discrete-time state space disturbance observer. It does not require disturbance modeling, plant inverse modeling and/or Q filter. In frequency domain, its performance is evaluated in terms of sensitivity and complementary sensitivity as well as gain and phase margin. Finally we discuss design criterion of state space disturbance observer considering its performance in frequency domain.

• 제어로봇시스템학회:학술대회논문집
• /
• 제어로봇시스템학회 2003년도 ICCAS
• /
• pp.2143-2146
• /
• 2003

We propose, for the first time to our knowledge, a novel gain-clamping method for EDFA in WDM Add/Drop networks by introducing a disturbance observer technique. The proposed gain-clamping control input consists of the nominal gain-clamping control such as PI(Proportional and Integral) control and the additional control input for the compensation of the effects caused by channel add/drops. The additional control input is designed using the wellknown disturbance observer technique and can be implemented very easily with general electric elements. We proved the superiority of the new technique over the previous methods by showing simulation result of minimized dips and spikes that appear in power profile of EDFA output.

• 대한기계학회논문집A
• /
• 제26권12호
• /
• pp.2519-2526
• /
• 2002

A disturbance observer-based vehicle stability controller is proposed in this paper. The lumped disturbance to the vehicle yaw rate dynamics caused by the uncertain factors such as uncertain tire forces and parameters is estimated by the disturbance observer, which is utilized by the robust controller to stabilize the lateral dynamics of the vehicle. The dynamics of the hydraulic actuator is incorporated in the vehicle stability controller design using the model reduction technique. Modular control design methodology is adopted to effectively deal with the mismatched uncertainty. Simulation results indicate that the proposed disturbance observer-based vehicle stability controller can achieve the desired reference tracking performance as well as sufficient level of robustness.

• 제어로봇시스템학회:학술대회논문집
• /
• 제어로봇시스템학회 2003년도 ICCAS
• /
• pp.312-315
• /
• 2003

This paper deals with robust control problems of linear systems with matched nonlinear uncertainties. In order to handle the uncertainties, a Lyapunov min-max control approach can usually be adopted. By the way, the min-max control input is required to be switched and provokes chattering phenomena which limit the practical implementation. The magnitude of switching control input which cause chattering is dependent on the size of uncertainties. In this paper, it is shown that the magnitude of the min-max control input can be made small using a well-known disturbance observer technique and only considers the disturbance observing errors. The chattering phenomena can be reduced as small as possible by selecting a high diturbance observer gain. The simulations show that the min-max control with a disturbance observer can reduce chattering phenomena much smaller and guarantee much better robust performance rather than the one without a disturbance observer.

• 전기학회논문지
• /
• 제58권1호
• /
• pp.187-192
• /
• 2009

This paper presents a method for designing a robust controller that alleviates disturbance effects and compensates performance degradation owing to the time-delay. Disturbance observer(DOB) approach as a tool of robust control has been widely employed in industry. However, since the Pade approximation of time-delay makes the plant non-minimum phase, the classical DOB cannot be applied directly to the system with time-delay. By using a new DOB structure for non-minimum phase systems together with the Smith Predictor, we propose a new controller for reducing the both effects of disturbance and time-delay. Moreover, the closed-loop system can be made robust against uncertain time-delay with the help of a Pill controller tuning method that is based on a second-order plus dead time modeling technique.

• 한국통신학회논문지
• /
• 제29권4A호
• /
• pp.363-369
• /
• 2004

본 논문에서는 파장분할다증(WDM) 첨가(add)/절취(drop)망에서 채널의 add/drop에 따라 망 내에 있는 EDFA의 이득을 제어함에 있어 세계 최초로 외란 간측기법을 적용하는 새로운 이득-클램핑(gain-clamping) 방법을 제안한다. 이득-클램핑을 위한 제어신호는 공칭 제어신호와 채널의 add/drop에 따른 이득변동을 보정하기 위한 부가제어신호로 구성된다. 외란 관측기법에 근거하여, 부가 제어신호는 채별의 add/op에 의해 발생하는 추정 외란을 보정할 수 있도록 설계하였다. 이러한 부가 제어신호를 생성하는 회로는 간단한 전자소자를 이용하여 쉽게 구현할 수 있다. 모의실험을 통해 본 논문에서 제안하는 방법을 사용할 때 채널의 add/drop 과정에서 EDFA의 출력 파형에 나타나는 이득변화에 따른 요철이 최소로 됨을 보여줌으로써 본 방법이 기존의 여타 방법들에 비해 월등함을 입증하였다.

• 반도체디스플레이기술학회지
• /
• 제23권2호
• /
• pp.92-99
• /
• 2024

As semiconductor processes require several nanometers precision, the importance of motor control is increasing in semiconductor equipment. Due to unpredictable uncertainties such as friction and mechanical vibrations achieving precise position control in semiconductor processes is challenging. The internal model principle-based controller is a control technique that ensures robust steady-state performance by incorporating a model of the reference and disturbance. The disturbance observer-based controller is a prominent robust control technique implemented to cope with various nonlinearities and uncertainties. Provided that the two controllers can be designed to exhibit equivalent performance under certain conditions, this paper demonstrates through experiments that they yield identical results for the case of a BLDC position control problem. The experimental results also indicate that they can offer enhanced robustness compared with the conventional PID controller in the presence of a time-varying disturbance.

• Transactions on Control, Automation and Systems Engineering
• /
• 제4권4호
• /
• pp.319-323
• /
• 2002

In this paper, we consider the track-following control problem in the optical data storage systems in the presence of the eccentricity. The eccentricity results in the radial deviation of the objective lens so that it degrades the reliability of the data decoding system. To cope with the eccentricity, an adaptive disturbance compensation technique is newly proposed in the time domain based on a disturbance observer of reduced order, which effectively estimates the low frequency components of the disturbance. The proposed compensator is simply added to the conventional feedback control. The error dynamics of the observer and the sensitivity analysis are given to illustrate the effectiveness of the proposed approach. Finally, through experiments in an optical storage system, the feasibility of the proposed approach is verified.

• 전기학회논문지
• /
• 제66권4호
• /
• pp.666-671
• /
• 2017

A disturbance-observer-based adaptive neural tracker design problem is investigated for a class of perturbed uncertain non-affine nonlinear systems with unknown control direction. A nonlinear disturbance observer (NDO) design methodology using neural networks is presented to construct a tracking control scheme with the attenuation effect of an external disturbance. Compared with previous control results using NDO for nonlinear systems in non-affine form, the major contribution of this paper is to design a NDO-based adaptive tracker without the sign information of the control coefficient. The stability of the closed-loop system is analyzed in the sense of Lyapunov stability.