• Journal of the Korean Society for Precision Engineering
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• v.26 no.5
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• pp.120-127
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• 2009

An electric furnace, inside which desired temperatures are kept constant by generating heat, is known to be a difficult system to control and model exactly because system parameters and response delay time vary as the temperature and position are changed. In this study the heating system of ceramic drying furnaces with time-varying parameters is mathematically modeled as a second order system and control parameters are estimated by using a RIV (Recursive Instrumental-Variable) method. A modified bang-bang control with magnitude tuning is proposed in the time optimal temperature control of ceramic drying electric furnaces and its performance is experimentally verified. It is proven that temperature tracking of adaptive time optimal control using a second order model is more stable than the GPCEW (Generalized Predictive Control with Exponential Weight) and rapidly settles down by pre-estimation of the system parameters.

• Smart Structures and Systems
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• v.10 no.1
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• pp.33-46
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• 2012

To reduce the vibration of cable-stayed bridges, conventional magnetorheological (MR) damper control system (CMRDS), with separate power supply, sensors and controllers, is widely investigated. In this paper, to improve the reliability and performance of the control system, one adaptive MR damper control system (AMRDS) consisting of MR damper and piezoelectric energy harvester (PEH) is proposed. According to piezoelectric effect, PEH can produce energy for powering MR damper. The energy is proportional to the product of the cable displacement and velocity. Due to the damping force changing with the energy, the new system can be adjustable to reduce the cable vibration. Compared with CMRDS, the new system is structurally simplified, replacing external sensor, power supply and controller with PEH. In the paper, taking the N26 cable of Shandong Binzhou Yellow River Bridge as example, the design method for the whole AMRDS is given, and simple formulas for PEH are derived. To verify the effectiveness of the proposed adaptive control system, the performance is compared with active control case and simple Bang-Bang semi-active control case. It is shown that AMRDS is better than simple Bang-Bang semi-active control case, and still needed to be improved in comparison with active control case.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2002.10a
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• pp.313-320
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• 2002

A new semi-active control strategy for seismic response reduction using a neuro-controller and a magnetorheological (MR) fluid damper is proposed. The proposed control system consists of the improved neuro-controller and the bang-bang-type controller. The improved neuro-controller, which was developed by employing the training algorithm based on a cost function and the sensitivity evaluation algorithm replacing an emulator neural network, produces the desired active control force, and then the bang-bang-type controller causes the MR fluid damper to generate the desired control force, so long as this force is dissipative. In numerical simulation, a three-story building structure is semi-actively controlled by the trained neural network under the historical earthquake records. The simulation results show that the proposed semi-active neuro-control algorithm is quite effective to reduce seismic responses. In addition, the semi-active control system using MR fluid dampers has many attractive features, such as the bounded-input, bounded-output stability and small energy requirements. The results of this investigation, therefore, indicate that the proposed semi-active neuro-control strategy using MR fluid dampers could be effectively used for control of seismically excited structures.

• The Proceedings of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.7 no.4
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• pp.51-58
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• 1993

This paper proposed a minmum time control method by a parabolic switching function to high speed position control, with high accuracy, of a Linear OC Motor A proposed method is organized simply and a bang-bang control's signal switched on a parabola type switching function in the phase for a minimum time control realization. However, a sliding mode occurs owing to system's modelling errors, so the minimum time control is realized a once switching bang-bang control by repeating trial experiments. Next time, in a neighborhood of the origin in the phase plane, a Linear OC Motor is stopped at the origin by the linear feedback control.

• Journal of the Korean Mathematical Society
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• v.35 no.1
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• pp.115-126
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• 1998

We study the optimal control problem of system governed by retarded functional differential $$ x'(t) = A_0 x(t) + A_1 x(t - h) + \\ulcorner\ulcorner\ulcorner_{-h}^{0} a(s)A_2 x(t + s)ds + B_0 u(t) $$ in Hilbert space H. After the fundamental facts of retarded system and the description of condition so called a weak backward uniqueness property are established, the technically important maximal principle and the bang-bang principle are given. its corresponding linear system.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.45 no.10
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• pp.872-880
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• 2017

Usually, on/off control method is a way to control the thruster. Bang-Bang Control, PWM(Pulse Width Modulator) and PWPF(Pulse Width Pulse Frequency) are widely used as a typical way. When we are designing PWPF, the incorrectly designed parameters($K_m$, ${\tau}$, $U_{on}$, $U_{off}$, $U_m$) make trouble, such as the phase lag, the wasted fuel, the reduced system life. Therefore, the effect of parameters on the system performance should be analyzed before the proper parameters are selected. In this paper, we suggest the PWPF parameters design method by performing a static analysis, and analyze the interactive effects on design parameters by performing a dynamic analysis and simulation.

• 제어로봇시스템학회:학술대회논문집
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• 1989.10a
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• pp.118-123
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• 1989

This work deals with fast-to-compute global control laws for time-optimal motion of strongly nonlinear dynamic systems like resolute robots. the theory of cell-to-cell mappings for dynamical systems offer the possibility of doing the vast majority of the control law computation offline in case of time optimization with constrained inputs. These cells result from a coarse discretization of likely swaths of state space into a set of nonuniform, contiguous volumes of relatively simple shapes. Once the cells have been designed, the bang-bang schedules for the inputs are determined for all likely starting cells and terminating cells. the resulting control law is an open-loop optimal control law with feedback monitoring and correction.

• Proceedings of the KIEE Conference
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• 1990.11a
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• pp.314-318
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• 1990

This paper deals with the transient analyses of both the one-phase ICB circuit and the three-phase ICB circuit. During the transient switching intervals, overvoltages or voltage unbalances may be produced on the capacitors. The three-step and four-step transient switching sequences were discussed and compared on the basis of phase shifting. Also, simple control method using bang-bang control was proposed and the digital simulations were carried out. As the results, it is verified that the proposed control technique is efficient.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 1996.04a
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• pp.203-208
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• 1996

This paper consider the control for the vehicle suspension system using electro-rheological damper. The study is performed by using of FLC(Fuzzy Logic Controller). The model used in the simulation is quarter car and the road disturbance is regarded as white noise random process with zero mean. Proposed control technique shows good agreement compared with the result from the conventional on-off/bang-bang type control technique.

• The Journal of Korean Medicine Ophthalmology and Otolaryngology and Dermatology
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• v.29 no.3
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• pp.74-94
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• 2016

Objectives : YangHyulEum Gami-Bang(YHEG) is a hair care extracts which is composed of fourteen plant extracts used in oriental medicine. The purpose of this study is to investigate the effect of YangHyulEum Gami-Bang(YHEG) on the alopecia and hair growth.Methods & Results : The herbal extracts from YangHyulEum Gami-Bang(YHEG) was tested using in vivo and in vitro test models. 1. The YHEG extracts showed effect on the DNA proliferation of the hair dermal papilla cells measured by [3H]thymidine incorporation. 2. YHEG showed promoting on the expression of growth factors such as IGF-1, KGF-1 and inhibiting on the expression of inhibitory hair growth factor such as TGF-β1, BMP-2 estimated by qPCR. 3. The YHEG extracts showed effect on the activation of β-catenin in the dermal papilla cells. 4. YHEG showed inhibitory effects of NO synthesis at 0.2% concentrations. 5. YHEG showed effects in the expression of IL-1β, TNF-α, IL-6, COX-2 and iNOS gene in the LPS stimulated RAW 264.7 cells. 6. The hair growth index of the YHEG extracts ranked at over 2 when compared to control group which was ranked at 0. 7. The hair follicle number, length and size of the experimental group were remarkably higher than the control group in the histological observation.Conclusions : These results suggest that YangHyulEum Gami-Bang(YHEG) has hair growth promoting activity and it can be used as a potent treatment agent for preventing hair loss and stimulating hair growth for treatment of alopecia.