• 제어로봇시스템학회:학술대회논문집
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• 1989.10a
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• pp.473-476
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• 1989

Quadratic weighting matrices have an effect on the transition and steady state responses in a LQ tracking problem. They are usually decided on trial and error in order to get a good response. In this paper a method is presented which calculates a steady - state deviation without solving Riccati equation. By using this method, a new procedure for selecting the weighting matrices is proposed when a tolerance on the steady - state deviation is given.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.27 no.8
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• pp.1158-1164
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• 2003

Steady-state structure and acoustic-pressure responses of $H_2$/Air counterflow diffusion flames are studied numerically with a detailed chemistry in view of acoustic instability. The Rayleigh criterion is adopted to judge acoustic amplification or attenuation from flame responses. Steady-state flame structures are first investigated and flame responses to various acoustic-pressure oscillations are numerically calculated in near-equilibrium and near-extinction regimes. The acoustic responses of $H_2$/Air flame show that the responses in near-extinction regime always contribute to acoustic amplification regardless of acoustic-oscillation frequency Flames near extinction condition are sensitive to pressure perturbation and thereby peculiar nonlinear responses occur, which could be a possible mechanism in generating the threshold phenomena observed in combustion chamber of propulsion systems.

• Proceedings of the KIEE Conference
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• 1987.11a
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• pp.530-533
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• 1987

In high-frequency switched mode converters, Series Resonant Converter (SRC) is investigated using state-plane method. Phase plane trajectories of the SRC permit a direct closed form solution of the steady state operation and can make problems easy to solve. This paper describes steady state responses and characteristics of the SRC with respect to various circuit factors. The magnitute of steady state response and the average current through load are clearly related to how such the switching frequency differs from the resonant frequency. The results of the steady state analysis can be used to estimate the device and component stress on the power circuit.

• Journal of Institute of Control, Robotics and Systems
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• v.3 no.2
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• pp.162-168
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• 1997

Digital variable structure controller(DVSC) is implemented to control the temperature for the hot water heating circulating pump control system. For the DVSC, a control algorithm is suggested, which using a nonlinear sliding surface and a PID sliding surface outside and inside of steady state error boundary layer, respectively. Smith predictor algorithm is used for the compensation of long dead time. The DVSC of the suggested algorithm yields improved control performance compared with the one of existing algorithm. The system responses with the suggested DVSC shows good responses without overshoot and steady state error inspite of heating load change. By decreasing sampling time, dead time and rise time are increasing, and system output noise by flow dynamics is amplified.

• Proceedings of the KSME Conference
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• 2007.05b
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• pp.3407-3412
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• 2007

The performance characteristics of the polymer electrolyte fuel cells (PEFCs) were investigated under various humidification conditions at steady-state and transient conditions. The PEFC studied in this study was characterized by I-V curves in potentiostatic mode. The I-V curves representing steady-state performance were obtained from OCV to 0.25V, and the dynamic performance responses were obtained at some points of voltages. The anodic external humidification was applied and the humidity was controlled from 20% to 100%. The effects of relative humidity of hydrogen were measured with the dry air at the cathode. At high voltage region, the performance at high temperature was higher, but at low voltage region, low temperature condition showed the higher performance. The dynamic responses were observed at the instant when the voltage of the PEFC was changed. It was observed that the performance reached steady-state earlier with the increase of temperature.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.27 no.4
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• pp.440-446
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• 2003

Steady-state structure and acoustic pressure responses of GH$_2$-LOx diffusion flames in stagnation-point flow configuration have been studied numerically with a detailed chemistry to investigate the acoustic instabilities. The Rayleigh criterion is adopted to judge the instability of the GH$_2$-LOx flames from amplification and attenuation responses at various acoustic pressure oscillation conditions for near-equilibrium to near-extinction regimes. Steady state flame structure showed that the chain branching zone is embedded in surrounding two recombination zones. The acoustic responses of GH$_2$-LOx flame showed that the responses in near-extinction regime always have amplification effect regardless of realistic acoustic frequency. That is, GH$_2$-LOx flame near-extinction is much sensitive to pressure perturbation because of the strong effect of a finite-chemistry.

• Journal of Drive and Control
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• v.13 no.3
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• pp.24-31
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• 2016

The performance characteristics of a dynamic control system are evaluated according to the transient and steady-state responses. The transient performance is the controllability of the output for the tracking of the reference or the ability to reduce or reject the effects of unwanted disturbances; alternatively, the steady-state performance is represented by the magnitude of the control error at the steady state. As the effects of the two performances on each other are reciprocal, a controller design that shows a zero steady-state error for the ramp input is uncommon because of the challenge regarding the achievement of an acceptable transient response. This paper proposes a PI+double-integral controller for the elimination of the steady-state error for the ramp input while a sound transient performance is maintained. The control-gain design procedure is described by the second-order response for the step input and the response of the error dynamics for the ramp input. The PI+double-integral controller is designed for the first-order transfer function that is derived from a system identification with the open-loop experiment data of the dc-motor. The simple structure of the proposed controller enables the adoption of a low-end microcontroller for the implementation of a real-time control. The experiment results show that the control performance is as effective as that of the simulation analysis for the operating point of linear system; furthermore, the PI+double-integral controller can be conveniently applied to the control system, which is desirable for the improvement of the steady-state error.

• 제어로봇시스템학회:학술대회논문집
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• 1993.10a
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• pp.1188-1193
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• 1993

For the HST(Hydrostatic Transmission) consisted of a variable displacement axial piston pump and motor, a speed controller with efficiencies considered is proposed. To consider a efficiency in speed control, the displacements of pump and motor which maximize a steady state efficiencies with a various load torque are calculated through computer simulation and these results are reflected to speed controller which has PI control structure with cross over control scheme. It is shown through computer simulation that the proposed controller gives better steady state efficiencies compared with the conventional controller and good transient responses.

• 전기의세계
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• v.30 no.5
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• pp.291-296
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• 1981

In the paper, in order to get the characteristics of the saccadic and the smooth pursuit movements of the oculomotor systems, a revised stochastic sampled data model suggested by Young et. al. was simulated and analyzed by using the MIMIC language. The results are summerized as follows; (1) The predictability to the sinusoidal inputs increased as the input frequency increased, but at the frequency of 1.0[Hz] the prediction started to decrease. (2) The responses of the system drifted when the system was open-looped. (3) The responses showed the transient state during the first period of the input waves, and then moved into the steady state.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.36 no.3
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• pp.188-196
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• 1987

This paper describes a design method for the buck type switching regulator to improve transient and steady state performances. Necessary design considerations on the power stage are given before designing the controller to obtain better trandient responses with less control effort and a feedforward compensation is also given to effectively improve the steady state performance. In the design of the controller, a PIM (proportional-integral-measurable) control method with optimized constant feedback gains is presented to get better tansient and steady state performances without complicating the implementation of controller. Computer simulations and experimental results are given to show the usefulness of the presented technique.