• International Journal of Control, Automation, and Systems
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• v.4 no.4
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• pp.448-455
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• 2006

This paper deals with the observer design problem for a class of state-delayed nonlinear systems with or without time-varying norm-bounded parameter uncertainty. The nonlinearities under consideration are assumed to satisfy the global Lipschitz conditions and appear in both the state and measured output equations. The problem we address is the design of a nonlinear observer such that the resulting error system is globally asymptotically stable. For the case when there is no parameter uncertainty, a sufficient condition for the solvability of this problem is derived in terms of linear matrix inequalities and the explicit formula of a desired observer is given. Based on this, the robust observer design problem for the case when parameter uncertainties appear is considered and the solvability condition is also given. Both of the solvability conditions obtained in this paper are delay-dependent. A numerical example is provided to demonstrate the applicability of the proposed approach.

• The Transactions of the Korean Institute of Power Electronics
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• v.12 no.4
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• pp.324-331
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• 2007

This paper studies new estimation method for state of charge (SOC) of the hybrid electric vehicle lithium battery using sliding mode observer. A simple R-C Lithium battery modeling technique is established and the errors caused by simple modeling was compensated by the sliding mode observer. The structure of the sliding mode observer is simple, but it shows robust control property against modeling errors and uncertainties. The performance of the system has been verified by the UUDS test. The test results of the proposed observer system shows robust tracking performance under real driving environments.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.18 no.1
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• pp.90-102
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• 2009

In this paper, a tracking control problem for a mechanical servo system with nonlinear dynamic friction is treated. The nonlinear friction model contains directly immeasurable friction state and the uncertainty caused by incomplete modeling and variations of its parameter. In order to provide the efficient solution to these control problems, we propose a hybrid control scheme, which consists of a robust friction state observer, a RFNN estimator and an approximation error estimator with sliding mode control. A sliding mode controller and a robust friction state observer is firstly designed to estimate the unknown infernal state of the LuGre friction model. Next, a RFNN estimator is introduced to approximate the unknown lumped friction uncertainty. Finally, an adaptive approximation error estimator is designed to compensate the approximation error of the RFNN estimator. Some simulations and experiments on the mechanical servo system composed of ball-screw and DC servo motor are presented. Results demonstrate the remarkable performance of the proposed control scheme.

• 제어로봇시스템학회:학술대회논문집
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• 1997.10a
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• pp.199-202
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• 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.

• Journal of the Korean Institute of Telematics and Electronics B
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• v.31B no.2
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• pp.35-44
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• 1994

In this paper, an observer for linear discrete systems with unknown inputs is presented. The suggested observer can estimate the system state vector and the unknown inputs simultaneously. As an extension of the observer, a new fault diagnosis observer for linear discrete systems with structured uncertainty is presented. The fault diagnosis observer can detect and identify the actuator and the sensor faults as well. The stability conditionsand the design methods of the each observers are presented and the usability of the observers is shown via numerical examples.

• 제어로봇시스템학회:학술대회논문집
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• 2000.10a
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• pp.24-24
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• 2000

This paper proposes a design method of sliding mode observer for SISO linear systems with a disturbance input. We first construct an observer with a constant gain matrix, a feedforward injection map and an external feedforward compensation signal input. Using the second Lyapunov method, we present a sufficient condition for the existence of sliding mode observer. The proposed observer guarantees that the state error trajectories enter a certain region in finite time and remain inside thereafter.

• Journal of Electrical Engineering and Technology
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• v.4 no.2
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• pp.240-248
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• 2009

An approach to control the position for an interior permanent magnet synchronous motor (IPMSM) based on an adaptive integral binary observer is described. The binary controller with a binary observer is composed of a main loop regulator and an auxiliary loop regulator. One of its key features is that it alleviates chatter in the constant boundary layer. However, steady state estimation accuracy and robustness are dependent upon the thickness of the constant boundary layer. In order to improve the steady state performance of the binary observer and eliminate the chattering problem of the constant boundary layer, a new binary observer is formed by adding extra integral dynamics to the existing switching hyperplane equation. Also, the proposed adaptive integral binary observer applies an adaptive scheme because the parameters of the dynamic equations such as the machine inertia and the viscosity friction coefficient are not well known. Furthermore, these values can typically be easily changed during normal operation. However, the proposed observer can overcome the problems caused by using the dynamic equations, and the rotor position estimation is constructed by integrating the rotor speed estimated with a Lyapunov function. Experimental results obtained using the proposed algorithm are presented to demonstrate the effectiveness of the approach.

• Proceedings of the KIEE Conference
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• 1990.11a
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• pp.366-370
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• 1990

Generally, when servo system is used, various sensors are required to have comparison and compensation to the reference value. However, the sensors are relatively expensive, and cannot be always implemented because of the limit of space or the environmental conditions. In this paper, state observer systems without sensors are investigated. State observer systems are required to estimate the states quickly and exactly without being affected by the disturbances. Thus, in this paper, the effects of systems poles and observer poles are studies. In addition, the parameter variations are also considered to evaluate the effect of them to the observer based systems. Also, in this paper a whole system which includes compensators, observers and loads are considered and analysed by using numerical simulations.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.42 no.10
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• pp.816-822
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• 2014

The estimation of the angular rate of a satellite has been discussed. A nonlinear observer has been proposed based on the state-dependent Riccati equation method. A sufficient stability condition for the convergence of estimation error has been presented. This condition is related to a state-dependent algebraic Riccati equation. It has been derived by transforming nonlinear error dynamics into a Lipschitz nonlinearity. An observer gain is obtained from this condition. Numerical simulations are presented to verify the proposed method.

• 제어로봇시스템학회:학술대회논문집
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• 2001.10a
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• pp.27.3-27
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• 2001

In this paper, a robust receding horizon controller for uncertain linear time-varying systems is presented in the dynamic output-feedback form. The existing output-feedback receding horizon controller in the literature is composed of a state observer and a static controller associated with the observer states (similar to LQC control), where the fundamental assumption is that the state observer will supply the exact states as time goes up. The performance of those controllers may be much degraded and even the closed-loop stability may not be guaranteed when the system suffers from disturbances and uncertainties or is time-varying. The proposed controller, which is not necessary to have the state-observer, overcomes such difficulties. Using matrix inequality conditions on the terminal weighting matrix, the closed-loop system stability is guaranteed. Numerical examples are ...