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

• 한국자동차공학회논문집
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• 제20권3호
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• pp.58-66
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• 2012

This paper describes a design and a verification of linear state observers for a motorized seat belt system to estimate state information such as angular velocity and load torque. The motorized seat belt system provides functions to protect passengers and improve passenger's convenience. To realize these functions, sensors which can measure an angular velocity and load torque are needed. By use of the linear state observer, state information can be estimated without sensors. The motorized seat belt system is analysed and represented as a state space model which contains load torque as an augmented state. By the developed state space model, a full and reduced order observer are designed and verified by experiments. The full and reduced order observer are also compared from points of view of execution time and noise robustness.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2002년도 추계학술대회논문초록집
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• pp.320.1-320
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• 2002

In a hard disk drive (HDD) control system, a state-space controller/observer design is popularly adopted fur its advantages such as effective filtering of position and velocity, use of estimation error to handle servo defects, etc. In this report, a systematic method is proposed to accommodate the transport delay in the plant dynamics into the state estimator. (omitted)

• 대한전기학회논문지:시스템및제어부문D
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• 제53권11호
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• pp.760-767
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• 2004

In this paper, we propose sufficient conditions under which nonlinear systems can be transformed into nonlinear observer canonical form in the extended state space by virtue of dynamic system extension. The proposed scheme weakens two major restrictions of observer error linearization technique. Once a nonlinear system is transformed into nonlinear observer canonical form using dynamic system extension, a state observer can be easily designed. Two illustrative examples are included in order to compare the proposed scheme and observer error linearization method.

• 대한기계학회논문집A
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• 제36권12호
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• pp.1543-1549
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• 2012

이 논문은 냉간 압연공정의 다단 압연기에서 각 롤 간의 슬립 현상에 대한 상태공간 모델을 도출하고, 이를 이용하여 롤 간 슬립 상태 관측기 설계에 관한 연구를 수행한다. 먼저 뉴튼의 운동법칙을 이용하여 각 롤들의 회전 운동 방정식을 1계 비선형 미분 방정식으로 기술한 후, 테일러 급수를 이용하여 임의의 동작점에서 상태공간 방정식으로 선형화한다. 다음에는 선형화된 상태공간 방정식에 기초하여 Gopinath 구성법으로 측정 가능한 구동 롤을 제외한 종동 롤의 회전 각속도를 추정하는 최소차원 상태 관측기를 설계한다. 마지막으로 컴퓨터 시뮬레이션을 통하여 상태 관측기로부터 추정된 각 롤 회전각속도와 슬립률의 유용성을 고찰한다.

• 제어로봇시스템학회논문지
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• 제18권7호
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• pp.688-698
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• 2012

This paper deals with ROLSO (Reduced Order Luenberger State Observer) design to prevent jackknifing phenomenon of articulated vehicles consisting of the tractor and semi-trailer by using GPS. In addition, by applying the regulator system using ROLSO feedback system, simulation's result presents that articulated vehicle's states are stabilized than the human's PR time (Preception Response time) rapidly. This simulation verifies that the automatic control of articulated vehicle's can be applied for the accident prevention for the time that the driver is unable to manage with the sudden accident. For this simulation, by using the equation of planar motion, the modeling of the articulated vehicle was performed. This modeling was expressed in the state space model. And FOLSO (Full Order Luenberger State Observer), ROLSO were designed by using the state space model of an articulated vehicle's dynamics.

• Journal of Power Electronics
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• 제14권5호
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• pp.1038-1046
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• 2014

Lithium-ion batteries are widely used in hybrid and pure electric vehicles. State-of-charge (SOC) estimation is a fundamental issue in vehicle power train control and battery management systems. This study proposes a novel model-based SOC estimation method that applies closed-loop state observer theory and a comprehensive battery model. The state-space model of lithium-ion battery is developed based on a three-order resistor-capacitor equivalent circuit model. The least square algorithm is used to identify model parameters. A multi-state closed-loop state observer is designed to predict the open-circuit voltage (OCV) of a battery based on the battery state-space model. Battery SOC can then be estimated based on the corresponding relationship between battery OCV and SOC. Finally, practical driving tests that use two types of typical driving cycle are performed to verify the proposed SOC estimation method. Test results prove that the proposed estimation method is reasonably accurate and exhibits accuracy in estimating SOC within 2% under different driving cycles.

• 한국항공우주학회지
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• 제42권10호
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• pp.816-822
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• 2014

위성의 각속도를 추정하는 비선형 관측기의 설계방법을 제안한다. SDRE 기법을 이용하여 관측기를 설계하는데, 오차 수렴에 대한 충분조건을 제시하였다. 대수 Riccati 형태의 이 조건은, 비선형 항을 Lipschitz 형태로 변환하고 이에 대한 수렴 조건을 유도하여 구해진다. 이 조건으로부터 관측기의 게인을 구할 수 있으며, 시뮬레이션을 이용하여 제안한 방법을 검증하였다.

• 설비공학논문집
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• 제13권10호
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• pp.947-959
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• 2001

We propose a control scheme to control the indoor zone temperature via variable air volume (VAV) unit. To control the room temperature, state space model of the conditioned zone which is partitioned into nine artificial sectional regions is derived. The nonlinearity of the damper motion and actuator are considered for the practical use in the state space system description. The temperature control of the room temperature is performed by manipulating the degree of openness of the damper in relation to the local room temperature and the supplied air flow rate. In general, since a local temperature in the conditioned zone is measured, it is required to estimate the temperature values in each regions for the precise temperature control. We thus design a state observer to estimate the regional temperature, and use these values in the controller. The overall control system consists of the state observer based state feedback with the integral control. We compared the control results of the proposed scheme with those of cascade proportional and integral (PI) control, and showed that the scheme achieved precise control of the conditioned system.

• International Journal of Aeronautical and Space Sciences
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• 제15권2호
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• pp.163-172
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• 2014

This paper proposes a novel guidance law based on the block backstepping sliding mode control and extended state observer (ESO), which also takes into account the autopilot dynamic characteristics of the near space interceptor (NSI), and the impact angle constraint of attacking the maneuvering target. Based on the backstepping control approach, the target maneuvers and the parameter uncertainties of the autopilot are regarded as disturbances of the outer loop and inner loop, respectively. Then, the ESO is constructed to estimate the target acceleration and the inner loop disturbance, and the block backstepping sliding model guidance law is employed, based on the estimated disturbance value. Furthermore, in order to avoid the "explosion of complexity" problem, first-order low-pass filters are also introduced, to obtain differentiations of the virtual control variables. The stability of the closed-loop guidance system is also proven, based on the Lyapunov theory. Finally, simulation results demonstrate that the proposed guidance law can not only overcome the influence of the autopilot dynamic delay and target maneuvers, but also obtain a small miss distance.