• Phonetics and Speech Sciences
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• v.3 no.3
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• pp.27-33
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• 2011

This paper explores two articulatory characteristics of inter-consonantal coordination observed in lingual-lingual (/kt/, /ks/) and labial-lingual (/pt/) sequences. Using electromagnetic articulometry (EMMA), temporal aspects of the lip movement and lingual movement (of the tongue tip and the tongue dorsum) were examined. Three sequences (/ks/, /kt/, /pt/) were investigated in two respects: gestural overlap in C1C2 and formation duration of coronals in C2 (/t/ or /s/). Results are summarized as follows. First, in a sequence of two stop consonants gestural overlap did not vary with order contrast or a low-level motor constraint on lingual articulators. Gestural overlap between two stop consonants was similar in both /kt/ (lingual-lingual; back-to-front) and /pt/ (labial-lingual; front-to-back). Second, gestural overlap was not simply constrained by place of articulation. Two coronals (/s/ and /t/) shared the same articulator, the tongue tip, but they showed a distinctive gestural overlap pattern with respect to /k/ in C1 (/ks/ (less overlap) < /kt/ (more overlap)). Third, temporal duration of the tongue tip gesture varied as a function of manner of articulation of the target segment in C2 (/ks/ (shorter) < /kt/ (longer)) as well as a function of place of articulation of the segmental context in C1 (/pt/ (shorter) < /kt/ (longer)). There are several implications associated with the results from Korean non-assimilating contexts. First, Korean can be better explained in the way of its language-specific gestural pattern; gestural overlap in Korean is not simply attributed to order contrast (front-to-back vs. back-to-front) or a physiological motor constraint on lingual articulators (lingual-lingual vs. nonlingual-lingual). Taking all factors into consideration, inter-gestural coordination is influenced not only by C1 (place of articulation) but also C2 (manner of articulation). Second, the jaw articulator could have been a factor behind a distinctive gestural overlap pattern in different C1C2 sequences (/ks/ (less overlap) vs. /kt/ and /pt/ (more overlap)). A language-specific gestural pattern occurred with reference to a physiological motor constraint on the jaw articulator.

• Proceedings of the KIEE Conference
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• 1992.07b
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• pp.620-622
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• 1992

Magnetic characteristics of a brushless disk type motor has been analyzed taking into account the magnetization distribution in the rotor magnet. This paper describes a method for calculating the 3D flux density in the air gap and calculates the induced voltage of the windings and the torque betweens the permanent magnet and the amateur current.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.38 no.12
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• pp.1041-1047
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• 1989

In recent years, a.c servomotors have been gradually replacing d.c servomotors in various high-performance applications such as machine tools and industrial robots. Inparticular, the high performance slip-frequency control of an induction motor, which is often called the vector control, is considered ane of th ebest a.c drives. In this paper, the transient state equations and vector control algorithms of an induction type servomotor are described mathematically by using the two- axis theory (d-q coordinates). According to the result of these algorithms, we scheme the speed control system for the motor in which the vector control is adopted to give high performance. Motor drive through a PWM inverter with power MOSFET is controlled so that the actual input current to the motor may track the current reference obtained from a micro-computer (8086 CPU). Driving experiments are performed in the range of 0 to 3000 rpm, and it is verified that high speed response is obtained for this system.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.50 no.3
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• pp.105-109
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• 2001

In this paper, the windmill type ultrasonic motors with 11.35 mm diameter, 2.87 mm thickness of metal endcap and 1.47 g weight were fabricated. Effects of slots and thickness on torque characteristic in the windmill type ultrasonic motor were investigated, when stator's slots were changed from 4, 6, 8 and thickness 0.15 mm, respectively. Specially designed metal endcaps with windmill shaped cutting can provide longitudinal and torsional displacements simultaneously as the ceramic disk vibrates radically. The windmill type ultrasonic motor has only three components: a stator element with windmill shape slotted metal endcap, a rotor and bearing. Ultrasonic motor stimulated to ultrasonic oscillations by piezoelectrics to drive a rotor via friction contact. The ultrasonic motor fabricated here was the windmill type ultrasonic motor operated by single-phase AC source. Bidirectional revolution using single-phase high frequency for driving the ultrasonic motor was presented.

• The Proceedings of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.9 no.6
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• pp.78-82
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• 1995

It is needed to robust control for D.C. servo motor according to industrial automation. However, when a motor has an effect of disturbance and variable load, it is very difficult to guarantee the robustness of the system. as a compensation way of solving this problem, in this paper, a expert supervisory control method for motor control system is presented. Expert supervisory controller is designed by error and error change, and nth control input is decided by the addition of (n-1)th control input and inference amount of increase or decrease. Control input of expert supervisory control is transmitted to input, and the disturbance effect decrease remarkable by control input. The robustness of D.C. servo motor using expert supervisory control is demonstrated by the computer simulation.

• KIEE International Transaction on Electrical Machinery and Energy Conversion Systems
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• v.2B no.4
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• pp.207-213
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• 2002

The paper introduces a switched reluctance motor drive system based on an 80C31 and an Intel 80C 196KB single-chip microprocessor control. Advance schemes are used in turn-on and turn-off angles with the power converter's main switches during traction and regenerative braking. The principles of traction speed control and braking torque control are given. The hardware and software patterns in the 80c31 and the Intel 80C196KB single-chip microprocessor control system are also presented.

• Proceedings of the KIEE Conference
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• 1988.07a
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• pp.83-86
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• 1988

In all sorts of primary factor which produce torque ripple of d.c brushless motor cogging torque which is generated from relation between permanent magnet rotor and salient pole cannot controled by external control system. So in this paper cogging torque is analysed by simple method in which slot fuctuion is introduced. And for reducing counterplan of cogging torque d.c brushless motor which plot auxiliary slot by inequality interval is proposed. Thus the quantitative torque characteristics of new motor which designed by this method is analysed by F.E.M and validity of this new design is proved.

• The Journal of the Korea institute of electronic communication sciences
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• v.8 no.11
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• pp.1707-1712
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• 2013

In this paper, we implement a hardware for motor control based on FPGA + embedded processor using Zynq EPP which is All Programmable SoC in order to improve a structural problem of motion control based on such as DSP, MCU and FPGA previously. The implemented motor controller that is fused controller with advantage of FPGA and embedded processor. The signal processing part of high velocity motor control is performed by motor controller based on FPGA. A motion profile and kinematic calculation that are required algorithm process such as operation of a complicate decimal point has processed in an embedded processor based on dual core. As a result of a hardware implementation, it has an advantage that has can be realized an effect of distribution process in one chip. It has also an advantage that is able to organize as a multi-axis motor controller through adding the IP core of motor control implemented on FPGA.

• Proceedings of the SAREK Conference
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• 2008.06a
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• pp.425-429
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• 2008

The present study has been conducted to improve temperature distribution in the motor housing of vacuum cleaner and reduce the development period by CFD analysis. CFD analysis is performed to investigate the thermal flow pattern in the motor housing and validated by experiments. The validation of CFD analysis is conducted by comparing the temperature distribution on motor housing cover. Through the present study the CFD analysis procedure in the motor housing of vacuum cleaner is established and various experimental materials are obtained. These analysis results can be used effectively as design factors of vacuum cleaner.

• 제어로봇시스템학회:학술대회논문집
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• 1986.10a
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• pp.580-585
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• 1986

This paper deals with "chattering" problem in variable structure control system. For digital computer control, chattering reduction algorithm in Analog-VSC is extended to Discrete-VSC. The proposed algorithm is applied to position control of D.C Servo Motor by using 6502 .mu.-processor. The improved transient response, as well as a considerable reduction of chattering, is illustrated experimentally.imentally.