• Journal of the Korean Mathematical Society
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• v.51 no.1
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• pp.99-111
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• 2014

In this paper, we deal with the problem of practical observer design and the practical stabilization for a class of perturbed impulsive systems. We show that, under the classical conditions of uniform complete controllability and uniform complete observability of the nominal system without impulsive effects, it is possible to design an observer controller for a class of perturbed linear impulsive system when the origin is not an equilibrium point.

• Journal of the Korea Convergence Society
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• v.4 no.4
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• pp.41-48
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• 2013

Observer design for system with unknown input was carried out. First, Kalman filter was considered to estimate system state with White noise. With the results of Kalman filter design, state observer, controller properties, including controllability and observability, and the Kalman filter structure and algorithm were also studied. Kalman filter algorithm was applied to Position and velocity measurement based on Kalman filter with white noise, and it was constructed and achieved by programming based on Matlab programming. Finally, observer for system with unknown input was constructed with the help of Gershgorin's disc theorem. With the designed observer, system states was constructed and applied to system with unknown input. By simulation results, estimation performance was verified. In this project, state feedback control theory, observer theory and relevant design procedure, as well as Kalman filter design were understood and used in practical application.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.65 no.4
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• pp.652-658
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• 2016

In practical control systems differences between nominal and real systems arise from internal uncertainties and/or external disturbances. This paper presents a model-based low-order disturbance observer for a sinusoidal disturbance with unknown constant offset. By using the disturbance model of a biased harmonic signal, the proposed method can successfully estimate the biased sinusoidal disturbance with unknown amplitude and phase but known frequency. At the first stage of the observer design, a model-based disturbance observer is designed when all the system states are measurable. Next, a sufficient condition is presented for the proposed observer to estimate the sinusoidal disturbance with a minimal-order additional dynamics using only output measurement. Comparative computer simulations are performed to test the performance of the proposed method. The simulation results show the enhanced performance of the proposed disturbance observer.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.6 no.1
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• pp.37-47
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• 2005

This Paper proposes a practical design and implementation methodology for a disturbance rejection controller. In a 2 Degree-Of-Freedom (DOF) structure, disturbance rejection performance can be improved without a high gain in forward-loop controller which might cause unwanted side-effects in conventional controller. But, since design methodology of 2 DOF controller is originally derived from the 2 DOF theory, it is not easy to utilize fer various industrial applications. Disturbance observer is a simple, but very effective 2 DOF controller. In this paper, practical issues are discussed from basic idea of DOB to technical procedure for design and implementation. Additionally, a methods and their examples of experimental modeling are explained. The proposed method is demonstrated by two examples of linear-type motor systems.

• Proceedings of the KIPE Conference
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• 2002.11a
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• pp.53-56
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• 2002

This paper presents neural observer that used to deadbeat load torque observer. Most practical systems are nonlinear, and it is general practice to use linear models to simplify their analysis and design. However, the locally linearized model is invalid for a large signal change. The neural observer is suggested to increase the performance of the load torque observer and main controller The output error and estimeted state is trianed by neural network of neural observer. As a result, the state estimation error is minimised and deadbeat load torque observer make use of corrected esimation state. To reduce of the noise effect of deadbeat load torque observer, the post-filter which is implemented by MA process, is adopted. As a result, the proposed control system becomes a robust and precise system against the load torque. A stability and usefulness, through the verified computer simulation, are shown in this paper.

• Journal of Institute of Control, Robotics and Systems
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• v.9 no.11
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• pp.883-890
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• 2003

Two GOS (Generalized Observer Scheme) type Fault Detection Isolation Schemes (FDIS), employing the bank of unknown input functional observers (UIFO) as a residual generator, are proposed to make the practical use of the multiple observer based FDIS. The one is IFD (Instrument Fault Detection) scheme and the other is PFD (Process Fault Detection) scheme. A design method of UIFO is suggested for robust residual generation and reducing the size of the observer bank. Several design objectives that can be achieved by the FDI schemes and the design methods to meet the objectives are described. An IFD system is constructed for the Boeing 929 Jetfoil boat system to show the effectiveness of the propositions. Major contributions of this paper are two folds. Firstly, the proposed UIFO approaches considerably reduce the size of residual generator in the GOS type FDI systems. Secondly, the FDI schemes, in addition to the basic functions of the conventional observer-based FDI schemes, can reconstruct the failed signal or give the estimates of fault magnitude that can be used for compensating fault effects. The schemes are directly applicable to the design of a fault tolerant control systems.

• Journal of the Korean Institute of Telematics and Electronics B
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• v.33B no.2
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• pp.28-36
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• 1996

By utilizing the interinsic structure of the underlying continous-time nonlinear system, one can design an approximate sampled-data observer improved with respect ot the sampling-time for the systems. In this paper, we characterize the conditions for the solvability of the improved approximate sampled-data nonlinear observer design problem. In particular, it is shown that when the dimension of the state space is two, the nonlinear systems for which it is possible ot desing 3rd or higher order approximate sampled-data nonlinear observer are locally state-equivalent to an observable bilinear system. The practical implication is that seeking higher order approximate sampled-data nonlinear observer for nonlinear systems is very restricted.

• Proceedings of the KIEE Conference
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• 2006.10c
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• pp.187-189
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• 2006

In mechanical system, gear trains have backlash innately. With the presence of inherent backlash, the overall system performance is limited in many practical control systems. It has been reported that a disturbance observer has the property of effective removing disturbance and cutting measurement noise off. The plant is remodeled with modified disturbance observer to observe and compensate backlash characteristics. And this paper describes a method to design Q filter and to analyze the effects of disturbance and measurement noise to the output. It is shown that the vibration and tracking error caused by backlash were decreased and the time constant and relative degree are important factor to design Q filter.

• 전기의세계
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• v.30 no.12
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• pp.822-831
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• 1981

Many different schemes of the adaptive observer and controller have been developed for both continuous and discrete systems. In this paper we have presented a new scheme of the reduced order adaptive observer for the single input discrete linear time invariant plant. The output equation of the plant, is transformed into the bilinear form in terms of system parameters and the states of the state variable filters. Using the plant output equation the discrete implicit adaptive observer based on the similar philosophy to Nuyan and Carroll is derived and the parameter adaptation algorithm is derived based on the exponentially weighted least square method. The adaptive model following control system is also constructed according to the proposed observer scheme. The proposed observer and controller are rather than simple structure and have a fast adaptive algorithm, so it may be expected that the scheme is suitable to the practical application of control system design. The effectiveness of the algorithm and structure is illustrated by the computer simulation of a third order system. The simulation results show that the convergence speed is proportinal to the increasing of weighting factor alpha, and that the full order and reduced order observer have similar convergence characteristics.

• Journal of the Korean Institute of Telematics and Electronics B
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• v.31B no.3
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• pp.47-52
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• 1994

In industrial multivariable plants, it is often the case that all of plant outputs are measured not simultaneously, but seriallu. While Reference 1 proposed a special type of observer (referred to as "serial-sampling" type obserrversL. which was provento be very effective in this situation, it alsopointed out that the observer may have some minor problems in case of practical applications. In this paper, it isshown that these kind of problems can be resolved by proving the existence of the solution of the simultaneous equations (35) of Reference 1.