• Proceedings of the KIEE Conference
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• 1991.07a
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• pp.615-618
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• 1991

In this paper deals with instantaneous torque control of induction motor by vector control. The induction motor is modelled from nonlinear to linearized in condition to its control by vector control method and we obtained simple model as like as a separately excited DC motor drive system. This paper presents the fully digital controlled induction motor drive system based on the proposed linearized method and the control circuit of system consists of 16bits micro computer and all the function are implemented with software.

• 제어로봇시스템학회:학술대회논문집
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• 2002.10a
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• pp.91.3-91
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• 2002

This paper describes a design of an induction motor control system for industrial sewing machines. On the basis of vector control principle, the control system is simulated by using the ACSL, implemented on a DSP(TMS320C31).A space vector modulation is used as the inverter switching strategy. For the application of industrial sewing machines, A fast acceleration (deceleration) and removal of velocity ripples are required, because a sewing quality and sewing machines life time depends on these characteristics. The designed control system has fast dynamic characteristics and small speed vibration. The result is applied to the industrial sewing machine and result are shown.

• Journal of Electrical Engineering and Technology
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• v.13 no.5
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• pp.2116-2124
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• 2018

Magnetic levitation system with the advantages of non-contact, no friction and no wear can satisfy the requirement of high precision and high speed positioning. In this paper, magnetic levitation positioning stage which mainly consists of planar coil and HALBACH permanent magnet array and its control and driving system are designed. Magnetic levitation system is a highly nonlinear and strongly coupled complex system and its control performance can be influenced by the uncertainty and external disturbance. So exact feedback linearization method is used to realize exact linearization and decoupling, and a strategy of sliding mode control based on disturbance observer is proposed to compensate the uncertainty and external disturbance. Detailed proofs of observer's convergence property and system stability are derived. Both the simulation and experiment results verify the effectiveness of sliding mode control algorithm based on disturbance observer.

• Journal of Power Electronics
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• v.15 no.1
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• pp.235-245
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• 2015

This paper proposes a reactive current assignment and control strategy for a doubly-fed induction generator (DFIG) based wind-turbine generation system under generic grid voltage sag or swell conditions. The system's active and reactive power constrains during grid faults are investigated with both the grid- and rotor-side convertors (GSC and RSC) maximum ampere limits considered. To meet the latest grid codes, especially the low- and high-voltage ride-through (LVRT and HVRT) requirements, an adaptive reactive current control scheme is investigated. In addition, a torque-oscillation suppression technique is designed to reduce the mechanism stress on turbine systems caused by intensive voltage variations. Simulation and experiment studies demonstrate the feasibility and effectiveness of the proposed control scheme to enhance the fault ride-through (FRT) capability of DFIG-based wind turbines during violent changes in grid voltage.

• Journal of Power Electronics
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• v.15 no.2
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• pp.443-454
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• 2015

This study proposes a novel one-cycle control scheme with a plug-in repetitive controller for load compensator. The novelty of this scheme lies in the combination of high dynamics and the simplicity of a one-cycle controller and good steady-state harmonic suppression ability of the repetitive controller. In addition, the proposed scheme can reduce the effect of the harmonics in phase voltage for the existence of the repetitive controller. Finally, experimental results on a three-phase, four-wire, three-level load compensator are reported to validate the effectiveness of the proposed control scheme.

• 제어로봇시스템학회:학술대회논문집
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• 1993.10b
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• pp.191-196
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• 1993

Since the welding process is complex and highly nonlinear, it is very difficult to accurately model the process for real-time control. In this paper, a discrete-time transfer function matrix model for gas metal arc welding process is proposed. Although this linearized model is valid only around the operating point of interest, the adaptation mechanism employed in the control system render this model useful over a wide operating range. A multivariable one-step-ahead adaptive control strategy combined with a recursive least-squares method for on-line parameter estimation is implemented in order to achieve the desired weld bead geometries. Command following and disturbance rejection properties of the adaptive control system for both SISO and MIMO cases are investigated by simulation and experiment.

• Smart Structures and Systems
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• v.21 no.3
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• pp.287-303
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• 2018

Applications of energy harvesting from mechanical vibrations is becoming popular but the full potential of such applications is yet to be explored. This paper addresses this issue by considering an application of energy harvesting for the dual objective of serving as an indicator of structural health monitoring (SHM) and extent of control. Variation of harvested energy from an undamaged baseline is employed for this purpose and the concept is illustrated by implementing it for active vibrations of a pipe structure. Theoretical and experimental analyses are carried out to determine the energy harvesting potential from undamaged and damaged conditions. The use of energy harvesting as indicator for control is subsequently investigated, considering the effect of the introduction of a tuned mass damper (TMD). It is found that energy harvesting can be used for the detection and monitoring of the location and magnitude of damage occurring within a pipe structure. Additionally, the harvested energy acts as an indicator of the extent of reduction of vibration of pipes when a TMD is attached. This paper extends the range of applications of energy harvesting devices for the monitoring of built infrastructure and illustrates the vast potential of energy harvesters as smart sensors.

• Korean Journal of Organic Agriculture
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• v.17 no.2
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• pp.211-226
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• 2009

This experiment was conducted to investigate the effect of plant extracts, Chrysanthimum cinerariefolium and Melia azedarach to natural enemies and management of two spotted spider mite, Tetranychus urticae in organic strawberry fields in Jeonnam area. Plant extracts were highly toxic against Phytoseiulus persimilis, but low against Orius laevigatus. In the residual effect against Phytoseiulus persimilis, C. cinerariefolium showed lower level than M. azedarach which safe at least 1 day after spray. Emergence rates of parasitoids were about 40% at seven days after spray. Eretmocerus eremicus has very low emergence rate in treatment of M. azedarach, so it should release after spray of M. azedarach. To control of T. urticae C. cinerariefolium (CC) sprayed first and then sprayed C. cinerariefolium or M. azedarach (MA) for two and three times at a week interval. In the treatment of CC+MA and CC+CC+MA, the density of T. urticae was inhibited by 15th day but increased afterward. In CC+MA+CC, that of T. urticae inhibit from 8 days but also increased after I5th day. In case of spray M. azedarach (MA) first, the treatment of MA+CC, MA+MA+CC, MA+CC+MA suppressed T. urticae from the first day so the densy of T. urticae maintained low level to 30 days after spray. It suggested that M. azedarach should spray first and then alternative spray. When C. cinerariefolium sprayed before and behind to release of P. persimilis, the density of P. persimilis maintained unchanged but could not suppress T. urticae after 8 days which T. urticae increase time. When M. azedarach sprayed, the density of T. urticae rapidly decreased. It was accompanied with P. persimilis so T. urticae did not occur at 8 days after treatment.

• Journal of Sasang Constitutional Medicine
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• v.13 no.2
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• pp.1-7
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• 2001

Background and Purpose Through ${\ulcorner}$Dongyi Soose Bowon${\lrcorner}$, Dongmu Lee Je-ma supposed the minds of management for Sasang Constitutional Symptoms, which had been accomplished through several steps from his early writings to ${\ulcorner}$Dongyi Soose Bowon${\lrcorner}$ published in 1901. His basic minds of treatment for disease had been supposed early in ${\ulcorner}$Gyojapyungseongjam${\lrcorner}$ and ${\ulcorner}$Gyukchigo${\lrcorner}$, and had been completed to the Sasang Constitutional Symptoms and the minds of management for it, from ${\ulcorner}$Dongyi Soose Bowon Sasang Chobongyun${\lrcorner}$, ${\ulcorner}$Dongyi Soose Bowon${\lrcorner}$ written in 1894 to ${\ulcorner}$Dongyi Soose Bowon${\lrcorner}$ published in 1901. In this paper, I tried to find the minds of treatment of ${\ulcorner}$Dongyi Soose Bowon${\lrcorner}$, through classifying and researching the early minds of treatment (presented in ${\ulcorner}$Gyojapyungseongjam${\lrcorner}$, ${\ulcorner}$Gyukchigo${\ulcorner}$, ${\ulcorner}$Dongyi Soose Bowon Sasang Chobongyun${\lrcorner}$), and the latter minds of treatment (presented in ${\ulcorner}$Dongyi Soose Bowon${\ulcorner}$ written in 1894, ${\ulcorner}$Dongyi Soose Bowon${\lrcorner}$ published in 1901) Methods It was researched as bibliologically with his writings such as ${\ulcorner}$Gyojapyungseongjam${\lrcorner}$, ${\ulcorner}$Gyukchigo${\lrcorner}$, ${\ulcorner}$Dongyi Soose Bowon Sasang Chobongyun${\lrcorner}$, ${\ulcorner}$Dongyi Soose Bowon${\lrcorner}$ written in 1894, ${\ulcorner}$Dongyi Soose Bowon${\lrcorner}$ published in 1901. Results and Conclusions The conclusions were as follows. 1. At early, Dongmu Lee Je-ma pursued the minds of treatment at the autonomous control through 'Acquaintance and Self-control' based on 'the Knowledge of Nature and Desire', so emphasized 'self-control' as important point in treatment. 2. From ${\ulcorner}$Dongyi Soose Bowon Sasang Chobongyun${\lcorner}$, Dongmu summarized Sasang constitutional symptoms structurally in view of Morpho-imaginary. In ${\ulcorner}$Dongyi Soose Bowon Sasang Chobongyun${\lcorner}$ and ${\ulcorner}$Dongyi Soose Bowon${\lcorner}$ written in 1894, It was described in view of small organ, but in ${\ulcorner}$Dongyi Soose Bowon${\lcorner}$ published in 1901, suggested more updated in view of both large and small organ and to which added the concept of Hot and Cold. 3. Through reinterpreting the concept of interior and exterior disease in ${\ulcorner}$Sanghanrhon${\lcorner}$, the concept of Sasang constitutional symptoms had started as the minds of treatment for individual disease, but in ${\ulcorner}$Dongyi Soose Bowon${\lcorner}$ published in 1901, it was accomplished as the minds of broad management for Sasang Constitutional Symptoms. 4. In ${\ulcorner}$Dongyi Soose Bowon${\lcorner}$ published in 1901, the broad therapeutic prescriptions for management of Sasang constitutional symptoms were proposed newly, according to the accomplishment of Sasang constitutional symptomatic patterns, so these have different aims and are more important than that proposed previously. 5. The control in view of 'Knowledge and Deed' and the minds of management for Sasang constitutional symptoms are the minds and spirits for treantment and prevention against disease, which can maximize the power of autonomous self-treatment and manage all disease broadly.

• Journal of Institute of Control, Robotics and Systems
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• v.9 no.5
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• pp.374-378
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• 2003

A new discrete-time fuzzy output feedback control method for nonlinear systems with unknown time-delay is proposed. Ma et al. proposed an analysis and design method of fuzzy controller and observer and Cao et al. extend this result to be applicable fir the nonlinear systems with known time-delay. For the case of unknown time-delay, we derive the sufficient condition f3r the asymptotic stability of the equilibrium Point by applying Lyapunov-Krasovskii theorem and convert this condition into the LMI problem.