• 제어로봇시스템학회논문지
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• 제22권12호
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• pp.995-1001
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• 2016

The vehicle suspension system plays a very important part related with vehicle ride and handling. To improve the vehicle ride and handling many researches have been progressed from various damping parameter tuning techniques to the development of the electronic controlled suspension systems. In this paper, as one of the ride performance improvement a disturbance observer(DOB) based control system is applied to the quarter car vehicle model in order to show that the DOB can obtain good vibration isolation characteristics. First, the robust stability criterion for the DOB is introduced in detail, and then how DOB is applied to the 1/4 car vehicle model is represented, and finally to confirm the effectiveness of the DOB in vehicle ride performance improvement a computer simulation is carried out for various driving conditions.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2005년도 춘계학술대회 논문집
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• pp.523-530
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• 2005

This paper addresses sliding mode control (SMC) of the anti-lock braking system (ABS) with a compensator of model uncertainties such as vehicle parameter variation, unmodeled dynamics, and external disturbances. A sliding mode controller (SMC) is designed with a nominal vehicle model to achieve a desired wheel slip ratio. A disturbance observer (DOB) is introduced to compensate the model uncertainties and is designed with a transfer function of a hydraulic brake dynamics. Through simulations on the model uncertainties, it is verified that the sliding mode control with the DOB can give the simulation results better than the sliding mode control without the DOB.

• 전기학회논문지
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• 제58권7호
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• pp.1405-1410
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• 2009

Output voltage of a DC/DC power converter system is likely to be distorted if variable loads exist in the output terminal. This paper presents a new disturbance observer(DOB) approach to maintain a robust regulation of the output voltage of a boost type DC/DC converter. Unlike the buck-type converter case, the regulation problem of the boost converter is very complicated by the fact that, with respect to the output voltage to be regulated, the system is non-minimum phase. Owing to the non-minimum phase property the classical DOB approach has not been applied to the boost converter. Motivated by a recent result on the application of DOB to non-mimimum phase system, an output feedback control law is proposed by using a parallel feedforward compensator. Simulation results using the Simulink SimPowerSystems prove the performance of the proposed controller against load variation.

• 전기학회논문지
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• 제57권9호
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• pp.1612-1617
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• 2008

Since most disturbance observer (DOB) approaches have been limited to minimum-phase systems (or systems having no zero dynamics), we propose a new DOB structure that can be applied to non-minimum phase systems. The new structure features an additional system, which is called as V-filter, whose role is to yield a minimum phase system when connected with the plant in parallel. In order to design the V-filter systematically we first consider a class of linear systems that can be stabilized via PID controller. By inverting the controller's transfer function, we can simply construct the filter. A convenient way of designing V-filter is presented by using an iterative linear matrix inequality (LMI) algorithm. With an illustrative example the simulation result shows that substantial improvement in the performance has been achieved compared with the control system without the DOB.

• 제어로봇시스템학회논문지
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• 제22권6호
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• pp.397-402
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• 2016

This paper proposes a robust tracking control for constrained uncertain linear systems by combining a disturbance observer (DOB) and linear matrix inequality (LMI) based state feedback control. To this end, the state feedback control is designed for the nominal system and then a DOB based feed-forward control is added to reject uncertainties. In doing so, the DOB and state feedback controller are joined in a way that the combined control satisfies the input constraints and closed loop stability is guaranteed. Simulation results are provided to show that the proposed control scheme successfully stabilizes uncertain systems.

• 한국산학기술학회논문지
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• 제6권1호
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• pp.37-47
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• 2005

본 논문은 외란 제거 제어기의 실제적인 설계와 구현방법을 제안한다. 2 DOF 구조에서는 외란 제거의 성능은 순 방향 루프 제어기의 고 이득 없이 개선될 수 있다. 그러나, 2 DOF의 설계 방법이 2 DOF 수학적인 이론에 근거하기 때문에 다양한 응용 분야의 사용이 쉽지 않았다. 외란 관측기(Disturbance Observer, DOB)는 간단하지만, 매우 효과적인 2 DOF 제어기이다. 이 논문에서 기본적인 DOB 특성부터 설계와 구현의 기술적인 방법까지 실제적인 문제를 다룬다. 또한 실질적인 방법에 의하여 모델링하는 방법과 그 예를 설명하였다. 제안한 방법은 두 가지의 선형 모터 시스템으로 유용함을 증명하였다.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2002년도 ICCAS
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• pp.83.6-83
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• 2002

$\textbullet$ Disturbance observer $\textbullet$ Performance enhancement $\textbullet$ LFT formulation $\textbullet$ Structured singular value $\textbullet$ Maximum bandwidth of DOB $\textbullet$ DVD experiments $\textbullet$ Robust stable disturbance observer

• Journal of Electrical Engineering and Technology
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• 제7권2호
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• pp.273-280
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• 2012

Most variable speed wind turbines have pitch control mechanisms and one of their objectives is to protect turbines when the wind speed is too high. By adjusting pitch angles of wind turbine, the inlet power and the torque developed by the turbine are regulated. In this paper, the difference between the real wind speed and its rated value is regarded as a disturbance, and a component called disturbance observer (DOB) is added to the pre-designed control loop. The additional DOB based controller estimates the disturbance and generates a compensating signal to suppress the effect of disturbance on the system. As a result, the stability and the performance of the closed loop system guaranteed by an outer-loop controller (designed for a nominal system without taking into account of disturbances) are approximately recovered in the steady state. Simulation results are presented to verify the performance of the proposed control scheme.

• 제어로봇시스템학회논문지
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• 제22권5호
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• pp.339-345
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• 2016

This paper presents a robust speed control of an autonomous vehicle using a disturbance observer. For the purpose, the transfer function of speed dynamics of an autonomous vehicle is identified using step response data. Based on the identified transfer function, model based PID (Proportional-Integral-Derivative) control is designed. In order to design a robust control against load variations on the vehicle, a disturbance observer (DOB) based control is devised. The performance of the designed DOB based control is demonstrated by real experiments.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2008년도 심포지엄 논문집 정보 및 제어부문
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• pp.213-214
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• 2008

This paper considers design of a robust controller that alleviates disturbance effects and compensates performance degradation of plants with time-delay. Disturbance observer(DOB) approach as a tool of robust control has been widely employed in industry. However, since the time-delay makes the plant non-minimum phase, classical DOB cannot be applied directly to the time-delay system. By using a new DOB structure for non-minimum phase systems together with the Smith Predictor, we propose a new control algorithm for reducing the effects of disturbance and time-delay of the system.