• The Transactions of the Korean Institute of Electrical Engineers
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• v.41 no.8
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• pp.902-913
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• 1992

There have been several control schemes for the single input systems with unmeasurable state variables using variable structure control(VSC) theory. In the previous VSC, the systems must be represented in phase canonical form and the complete measurements for each state variable must be assumed. In order to eliminate these restrictions several VSC methods were proposed. And especially for the systems in phase canonical form with unmeasurable state variables, the reduced order switching function algorithm was proposed. But this method has many drawbacks and can not be used in the case of general form (not phase canonical form) dynamic system. Therefore this paper propose new construction method of switching fuction for the systems in phase canonical form, which reduce the restriction of reduced order switching function algorithm. And this algorithm can be realized for any state representation and adopted in the systems where not all states are available for switching function synthesis or control.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.46 no.4
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• pp.332-337
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• 2018

This paper presents the design optimization of fuel sensor location used to measure remained fuel amount in aircraft conformal fuel tank. The conformal fuel tank is utilized to expand the mission range in airplane, and the sensor location is a critical design variable determining the measurement accuracy. In this work, the sensor location is optimized to minimize unmeasurable fuel amount due to non-contact between fuel and sensor. The simplified model is prepared from the conformal fuel tank CATIA model, and the unmeasurable fuel amount is calculated. Then, the optimization is performed using MATLAB optimization solver. The optimized sensor location is validated by comparing with the location obtained using parametric study.

• Transactions of the Korean Society of Automotive Engineers
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• v.22 no.4
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• pp.36-45
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• 2014

Model based control methods are widely used to improve the control performance of diesel engine air systems because the control results of the air system significantly affect the emission level and drivability. However, the model based control algorithm requires a lot of unmeasurable states which are hard to be measured in a mass production engine. In this study, an air system model of the diesel engine is proposed to estimate 11 unmeasurable states using only sensors equipped in a mass production engine. In order to improve the estimation performance in the transient condition, dynamic characteristics of the air system are analyzed and implemented as discrete filters. Turbine and compressor efficiency models are also proposed to overcome a limitation of the constant or look-up table based efficiency values. The proposed air system model was validated in steady state and transient conditions by real-time engine experiments. The maximum error of the estimation for 11 physical states was 11.7%.

• 제어로봇시스템학회:학술대회논문집
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• 1996.10b
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• pp.233-236
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• 1996

This paper describes a liner state-space model for a flexible stick balencer. The method employed to generate the model utilizes a separable formulation of assumed modes to represents the transverse displacement due to bending Lagrangian dynamics are applied to determine the kinetic and potential energies for the system. The resultant dynamic equations are then organized into a state space model and linearized using Taylor series expansion method. A minimum order observer is designed to estimate unmeasurable states.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.35 no.2
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• pp.77-84
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• 1986

The design of observers for the systems with unknown and unmeasurable disturbances is treated. A generalized observer design method is proposed and existence conditions are established by combining the existing two different approaches` disturbance modelling approach by O'Reilly and algebraic approach by Kudva et. al.. The proposed approach, therefore, takes the advantages and removes the shortcomings of the existing two approaches in view points of dimensionality and existence conditions of the observer. To show the usefulness of the approach, a numerical example is given.

• 제어로봇시스템학회:학술대회논문집
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• 1986.10a
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• pp.474-478
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• 1986

The phenomenon of a continuous Steel-making process was studied with a set of collected equilibrium data for the steel-oxidation reactions. Mass and Heat balances were also established. Mass transfer constants which are physically unmeasurable but escential for the simulation study in the steel-making process were calculated from the experimental data using an optimization technique. Based on these data various operating conditions and process characteristics were examined.

• 제어로봇시스템학회:학술대회논문집
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• 1986.10a
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• pp.673-677
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• 1986

This paper deals with the state observer-controller which observes unmeasurable state variables of the system and then uses the estimated values as feedback signals. The linearized model is deduced from the nonlinear electrohydraulic servo system. The 4th order analog linear observer-controller and the 2nd order digital one are modelled and implemented using OP amplifiers and IBM PC/XT, respectively. The two observer are experimentally used in the control of an electrohydraulic system. The results are satisfactory in estimation performance and in tracking performance to command signal.

• 제어로봇시스템학회:학술대회논문집
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• 1986.10a
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• pp.571-575
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• 1986

The squirrel-cage induction motor can be characterized as a nonlinear and multi-input, multi-output system, and has the unmeasurable states which are the rotor currents. In this paper, the time-delayed output feedback method is applied to the speed control of induction motor driven by the current-controlled PWM inverter and its performance is investigated by using the computer simulation.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.33 no.3
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• pp.100-105
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• 1984

The optimal Load-Frequency Control law is presented with the performance criterion which includes the changing rate of governor speed. The authors propose two controllers. One is a dynamic controller using the method of state augmentation and the other is a constant gain controller with use of the trace function lemma by Kleinman. For a more practical realization, a reduced-order Luenberger observer is applied in order to identify unmeasurable states and power demand. The control schemees presented here are tested through the model developed by Elgerd, and the usefulness is demonstrated.

• Proceedings of the KIEE Conference
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• 1997.07c
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• pp.1156-1158
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• 1997

This paper presents the proposed full-order observer-based sliding mode power system stabilizer(FOOSMPSS) for finding unmeasurable state variables(torque angle, quadratic-axis transient voltage, exciter output voltage, voltage regulator output voltage and output voltage) by measuring angular velocity. The simulation results is shown by the comparison of the FOOPSS with the proposed FOOSMPSS.