• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2003년도 ICCAS
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• pp.452-457
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• 2003

An add-on type output regulator is proposed in this paper. By an add-on controller we mean an additional controller which operates harmonically with a pre-designed one. The role of the add-on controller is to reject a sinusoidal disturbance of unknown magnitude and phase but with known frequency. Advantages of the proposed controller include that (1) it can be used only when the performance of disturbance rejection needs to be enhanced, (2) when it is turned on or off, unwanted transient can be avoided (i.e., bumpless transfer), (3) it is designed for perfect disturbance rejection not just for disturbance reduction, (4) ability for perfect rejection is preserved even with uncertain plant model. This design may be promising for optical disc drive (ODD) systems in which disc eccentricity results in a sinusoidal disturbance. For ODD systems, the sensitivity function obtained by the pre-designed controller, which may have been designed by the lead-lag, $H_{\infty}$, or DOB (disturbance observer) technique, does not change much with the add-on controller except at the frequency of the disturbance. Since the add-on controller does the job of rejecting major eccentricity disturbance, the gain of the pre-designed controller does not have to be too high.

• International Journal of Control, Automation, and Systems
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• 제5권3호
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• pp.343-348
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• 2007

This paper presents an adaptive controller for the compensation of state-dependent disturbance with unknown amplitude in a digital servo motor system. The state-dependent disturbance is caused by friction and eccentricity between the wheel axis and the motor driver of a mobile robot servo system. The proposed control scheme guarantees an asymptotical stability for both the velocity and position regulation. An experimental result shows the effectiveness of the adaptive disturbance compensator for wheeled-mobile robot in a low velocity diffusion tracking. A comparative experimental study with a simple PI controller is presented.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2006년도 춘계학술대회논문집
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• pp.1212-1217
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• 2006

This study is concerned with static and sinusoidal disturbance rejection for a single periodic input disturbance with known period. In the area of active elimination of a disturbance force, the control input should have two different kinds of gains: one is to deliver a stable control and the other is a force component to cancel the external disturbance force. In this paper we employ a simple state feedback control law to make the balance beam stable and employ a linear observer to estimate the states which represent the external disturbance force components. Simulation results verify our proposed control method to reject a static and sinusoidal disturbance force.

• 한국산업정보학회논문지
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• 제4권1호
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• pp.58-62
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• 1999

본 논문은 엔진마운트에서 주기적인 미지의 외란에서 나타나는 시스템의 입출력으로부터의 시스템 동특성을 인식할 수 있는 응용가능성을 보여 주고자 한다. 일반적으로 외란 진동과 파장형태는 확실히 알려져 있지 않고 임의적으로 발생되고 있다. 단지 제어량인 입력과 외란이 섞여 있는 출력측정량만이 시스템인식을 위하여 사용될 뿐이다. 보다 일반화되어 개발된 시스템인식기술 알고리즘은 승용차 능동엔진마운트의 진동제어를 위하여 능동제어에 앞선 미지의 주기적외란을 포함한 동특성시스템에서의 수학적 모의시험을 통하여 시스템인식기술의 완벽성을 나타내고 있다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2007년도 심포지엄 논문집 정보 및 제어부문
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• pp.107-109
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• 2007

The recently-developed off-line learning control approaches for the rejection of periodic disturbances utilize the specific property that the learning system tends to oscillate in steady state. Unfortunately, the prior works have not clarified how closely the learning system should approach the steady state to achieve the rejection of periodic disturbances to satisfactory level. In this paper, we address this issue extensively for the class of linear systems. We also attempt to remove the effect of other aperiodic disturbances on the rejection of the periodic disturbances effectively. In fact, the proposed learning control algorithm can provide very fast convergence performance in the presence of aperiodic disturbance. The effectiveness and practicality of our work is demonstrated through mathematical, performance analysis as well as various simulation results.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2017년도 추계학술대회
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• pp.195-196
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• 2017

This paper proposes a permanent magnet synchronous motor(PMSM) control using a repetitive controller. Repetitive controllers are often used to eliminate periodic disturbances. Based on this, it is possible to alleviate the torque disturbance occurring at a constant cycle to the load of the motor. This paper proposes a method of rejecting periodically generated disturbances by using a repetitive controller and verified by simulation.

• 한국항해항만학회:학술대회논문집
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• 한국항해항만학회 1998년도 추계학술대회논문집:21세기에 대비한 지능형 통합항만관리
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• pp.175-180
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• 1998

In container crane system, the variation of cargo weight have effect on the travelling and sway control of load. For precise travelling and/or anti-sway control of crane system, the cargo weight should be measured and considered with control algorithm. But, and added attachment for measuring the cargo weight put restraint upon the control freedom for travelling and anti-sway. In this paper, we propose an estimation method for cargo weight in container crane system by using observation technique. First of all, we model the container crane system as a bilinear system and transform this model into linear system with external disturbance model. Second, we propose a generalized type - disturbance estimation observer and set a disturbance model, where, the cargo weight is related with the sway of load, and the sway is represented as a periodic external disturbance. Lastly, by using simulation we verify that the proposed algorithm of disturbance estimation observer is effective to estimate the cargo weight, and it will be used with anti-sway control algorithm.

• 제어로봇시스템학회논문지
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• 제2권2호
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• pp.73-80
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• 1996

This paper proposes a stabilizing controller for the multirate sampled-data systems which have a periodic output measurement scheme. A sufficient condition for maintaining observability in the multirate sampled-data system is derived and a design strategy for disturbance rejection is proposed. The proposed controller has IMC structure, and can be decomposed into the disturbance estimator and the inverse of the fast uniform sampled plant. We assume that the plant is open-loop stable and the disturbance consists of a sum of finite number of sinusoids with different frequencies. An example is presented for illustrations.

• 한국생산제조학회지
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• 제9권1호
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• pp.60-67
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• 2000

An improved disturbance rejection control scheme is presented for minimizing the position error due to the repeatable runout disturbances in high density disk drive systems The proposed control algorithm is capable of attenuating repeatable disturbances which is one of the major detractors to hard disk drive quality and performance. This is achieved by a sys-tematic combination of an optimal feedback component and a feedforward preview component. The feedback component is designed where the emphasis is placed on robustness. The feedforward component is on the basis of a preview control comprised of a measured disturbance signals which leads to better disturbance rejection capabilites. The designed con-troller is applied as a plug-in module to a high density hard disk drive with a pre-existing conventional servo controller. Simulations have been carried out to demonstrate the effectiveness of this control scheme in the reduction of the periodic disturbances.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1998년도 하계학술대회 논문집 G
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• pp.2309-2311
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• 1998

The attitude control of a double inverted pendulum with a periodical disturbance at link top is dealt in this paper. The proposed system is consisted of the double inverted pendulum and a disturbance link. The lower link is hinged on the plate to free for rotation in the vertical plane. The upper link is connected to the lower link through a DC motor. The DC motor is used to control the posture of the pendulum by adjusting the position of the upper link. The periodical disturbance can be generated by the additional link attached at the end of link 2 through another DC motor, which is the modeling of a posture for a biped supporting with one leg. The motor for the joint simulates the knee joint(or hip joint) and the disturbance for the legs moving in air. The algorithm for controlling a proposed inverted pendulum is consisted of a state feedback control and a fuzzy logic controller. The fuzzy controller keeps the center of gravity of the biped within the specified range through the nonlinear feedback compensator. The state feedback control takes over the role to maintain a desired posture regardless the disturbance at the link top. In these case, the change of the angle and COG of an upper link is compensated with on-line. Simulations with a mathematical model are conducted to show the validity of the proposed controller.