• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.25 no.10
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• pp.707-713
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• 2015

This paper proposes experimental results for control performance deterioration of a piezoelectric actuator under high temperature conditions due to external heat environment. In this work, a heat environment from 30 ℃ to 190 ℃ is established by a heat chamber which is capable of high temperature of heat environment. Inside the heat chamber, an experimental apparatus consisting of the stack type of piezoelectric actuator, laser sensor, gap sensor and temperature sensor is established. After evaluating temperature dependent blocking force, displacement and time response of a piezoelectric actuator inside the heat chamber, tracking control performances are evaluated under various temperature conditions via proportional-integral-derivative(PID) feedback controller. The desired position trajectory has a sinusoidal wave form with a fixed frequency. Control performances are experimentally evaluated at both room temperature and high temperature and presented in time domain.

• 제어로봇시스템학회:학술대회논문집
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• 2001.10a
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• pp.50.3-50
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• 2001

Nonlinear feedback control scheme for reactive distillation column has been proposed. The proposed control scheme is derived in the framework of Nonlinear Internal Model Control. The product compositions and liquid and vapor flow rates in sections of the reactive distillation column are estimated from selected tray temperature measurements by an observer. The control scheme is applied to example reactive distillation column in which two products are produced in a single column and the reversible reaction A + B = C + D occurs. The relative volatilities are favorable for reactive distillation so that the reactants are intermediated boilers between the light product C and the heavy product D. Ideal physical properties, kinetics and ...

• 제어로봇시스템학회:학술대회논문집
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• 1991.10a
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• pp.81-86
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• 1991

The iterative learning operation has been utilized in the temperature Control of a batch reactor. A generic form of feedback-assisted first-order learning control scheme was constructed and then various design and operation modes were derived through convergence and robustness analysis in the frequency domain. The proposed learning control scheme was then implemented on a bench scale batch reactor with the heat of reaction simulated by an electric heater. The results show a great improvement in the performance of control as the number of batch operations progressed.

• Proceedings of the KIEE Conference
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• 2003.07c
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• pp.1831-1833
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• 2003

Nowadays, CO2 lasers are used widely in many applications such as materials fabrication, communications, remote sensing and military purpose etc. Especially, CO2 lasers are in the spotlight at surface handling and heat processing. It is important to control the laser output power and beam quality in those fields. To increase beam qualify, We used the feedback system by various sensors. Although, CO2 lasers' output beam became feedback, its beam affected the irradiated material target already. Since, ideal real time control have still the problem to solve. Hence, we need the new proposal for more precise laser processing. So we expect the new effect how to change the irradiated material target as the kind of, processing time and output density caused by the CO2 laser beam. In this study, We have investigated the characteristics of the temperature and HAZ(Heat Affected Zone) by CO2 laser output with IR temperature sensor and RTD.

• Transactions of the Korean hydrogen and new energy society
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• v.18 no.3
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• pp.292-300
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• 2007

A dynamic system model of a proton exchange membrane fuel cell(PEMFC) has been developed. The PEMFC of this study has large active area with water cooling in order to simulate the performance of the commercially viable PEMFC system for the transportation. A PEMFC stack model is a transient thermal model which is respond to the dynamic change of the coolant temperature and the flow rate. The dynamic cooling system model has been developed to determine the coolant flow rate and the coolant temperature. Prior to the system level study, thermal management criteria have been set up and brought to the control command of the cooling system. Since the system model is designed to evaluate the effect of thermal management on the system performance, it is attempted to determine the proper control algorithm of the cooling system so that the PEMFC system is working on the thermal management criteria. As a result of simulation, feedback controlled cooling system consumes less power and produce more power comparing with that of conventionally controlled cooling system.

• 제어로봇시스템학회:학술대회논문집
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• 2003.10a
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• pp.1455-1459
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• 2003

This paper presents an n-steps on-off controller to maintain the desired temperature of the thermal process. The proposed technique is simple and convenient to implement based on the programmable commercial controller. The thermal plant model is experimented to observe the performances of the proposed controller. The experimental results included demonstrate the good performance of the proposed controller.

• Nuclear Engineering and Technology
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• v.53 no.11
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• pp.3685-3693
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• 2021

This paper presents a disturbance observer-based robust backstepping load-following control (DO-RBLFC) scheme for modular high-temperature gas-cooled reactors (MHTGRs) in the presence of actuator saturation and disturbances. Based on reactor kinetics and temperature reactivity feedback, the mathematical model of the MHTGR is first established. After that, a DO is constructed to estimate the unknown compound disturbances including model uncertainties, external disturbances, and unmeasured states. Besides, the actuator saturation is compensated by employing an auxiliary function in this paper. With the help of the DO, a robust load-following controller is developed via the backstepping technique to improve the load-following performance of the MHTGR subject to disturbances. At last, simulation and comparison results verify that the proposed DO-RBLFC scheme offers higher load-following accuracy, better disturbances rejection capability, and lower control rod speed than a PID controller, a conventional backstepping controller, and a disturbance observer-based adaptive sliding mode controller.

• Proceedings of the KIEE Conference
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• 2004.11c
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• pp.114-116
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• 2004

The temperature profile control issue in the resistive welder for the electronic parts is discussed. The average current of the welder tip depends on the phase(on-time) of the AC power and the tip temperature maintains or increases/decreases depending on the integral of the current square and heat loss, The basic PID control algorithm with thermo-couple feedback is difficult to track the temperature profile for various parts and optimal gain changes much. So constant gain PID algorithm is not enough to cover various electronic parts welding and a Fuzzy-PID automatic gain tuning algorithm is devised and added to conventional PID algorithm and this hybrid control architecture is implemented and the experimental results are shown.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.34 no.9
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• pp.45-52
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• 2006

In this study, a nonlinear control by feedback linearization method, one of nonlinear control schemes based on the nonlinear model, is proposed to suppress the flutter of a supersonic composite panel using piezoelectric materials. Most of the previous panel flutter controllers are the LQR(Linear Quadratic Regulator) which is based on the linear model. A nonlinear feedback linearizing controller proposed in this study considers the nonlinear characteristics of the system model. We use the actuator implemented by piezoceramic PZT. Using the principle of virtual displacements and a finite element discretization with the conforming four-node rectangular element, we first derive the discretized dynamic equations of motion, which are transformed into a nonlinear coupled-modal equations of motion of state space form. The effectiveness of the proposed method is also compared with the LQR based on the linear model through numerical simulations in the time domain using the Newmark method.

• KSBB Journal
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• v.4 no.3
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• pp.203-207
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• 1989

Software for the on-line feedback control of such variables as DO and temperature was developed and tested successfully for a real fermentation system. Several aspects like Pl, PID, DSC, and DDC were incorporated into the algorithm. Any kind of on-line computer control system can be successfully implemented without much difficulty.