• The Journal of Korean Physical Therapy
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• 제15권3호
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• pp.295-345
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• 2003

This study investigated activation of cerebral cortex in patients with hemiplegia that was caused by neural damage. Key-point control movement therapy of Bobath was performed for 9 weeks in 3 subjects with hemiplegia and fMRI was used to compare and analyze activated degree of cerebral cortex in these subjects. fMRI was conducted using the blood oxygen level-dependent(BOLD) technique at 3.0T MR scanner with a standard head coil. The motor activation task consisted of finger flexion-extension exercise in six cycles(one half-cycles = 8 scans = $3\;sec{\times}\;8\;=\;24\;sec$). Subjects performed this task according to visual stimulus that sign of right hand or left hand twinkled(500ms on, 500ms off). After mapping activation of cerebral motor cortex on hand motor function, below results were obtained. 1. Activation decreased in primary motor area, whereas it increased in supplementary motor area and visual association area(p<.001). 2. Activation was observed in bilateral medial frontal gyrus, middle frontal gyrus of left cerebrum, inferior frontal gyrus, inter-hemispheric, fusiform gyrus of right cerebrum, superior parietal lobule of parietal lobe and precuneus in subjedt 1, parahippocampal gyrus of limbic lobe and cingulate gyrus in subject 2, and inferior frontal gyrus of right frontal lobe, middle frontal gyrus, and inferior parietal lobule of left cerebrum in subject 3 (p<.001). 3. Activation cluster extended in declive of right cellebellum posterior lobe in subject 1, culmen of anterior lobe and declive of posterior lobe in subject 2, and dentate gyrus of anterior lobe, culmen and tuber of posterior lobe in subject 3 (p<.001). In conclusion, these data showed that Key-point control movement therapy of Bobath after stroke affect cerebral cortex activation by increasing efficiency of cortical networks. Therefore mapping of brain neural network activation is useful for plasticity and reorganization of cerebral cortex and cortico-spinal tract of motor recovery mechanisms after stroke.

• Journal of Trauma and Injury
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• 제21권2호
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• pp.71-77
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• 2008

Purpose: The Glasgow Coma Scale (GCS), though it is widely used for triage, has been criticized as being unnecessarily complex. Recently, a 3-point Simplified Motor Score (SMS, defined as obeys commands=2; localizes pain=1; withdrawals to pain or worse=0) was developed from the motor component of the GCS and was found to have a similar test performance for triage after traumatic brain injury when compared with the GCS as the criterion standard. The purpose of this study was to validate the SMS. Methods: We analyzed the patients who visited Kyungpook National University Hospital emergency center after traumatic brain injury from 2006 January to 2006 June. The test performance of the GCS, its motor component, and SMS relative to three clinically relevant traumatic brain injury outcomes (abnormal brain CT scans, Abbreviated Injury Scale $(AIS){\geq}4$, and mortality) were evaluated with areas under the receiver operating characteristic curves (AUCs). Results: Of 504 patients included in the analysis, 25.6% had an abnormal brain CT scans, 13.1% had $AIS{\geq}4$, and 5.0% died. The AUCs for the GCS, its motor component, and SMS with respect to the abnormal CT scans were 0.776, 0.715, and 0.716, and respectively, those for $AIS{\geq}4$ and mortality, were 0.969, 0.973, and 0.968, and 0.931, 0.909, and 0.909, respectively. Conclusion: The 3-point SMS demonstrated similar test performance when compared with the 15-point GCS score and its motor component for triage after traumatic brain injury in our populations.

• 전력전자학회논문지
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• 제17권3호
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• pp.246-251
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• 2012

This paper proposes a new position compensation method for misaligned Hall-effect sensors of BLDCM(Brushless DC Motor). If the Hall-effect sensors are installed at wrong position, the exact rotor position cannot be obtained. Therefore, when the BLDCM is controlled with this wrong position, the torque ripple can be increased and the average torque also decreases. The back-EMF of BLDCM can be obtained by using the voltage equation and by multiplying the back-EMF constant and rotor speed. At a constant speed, the estimated back-EMF by using the multiplication of the back-EMF constant and rotor speed is constant, but the estimated back-EMF from the voltage equation decreases at the commutation point because the line-to-line back-EMF of two conducting phases is start to decrease at this point. Therefore, by using the difference between these two estimated back-EMFs, the commutation point of the phase current can be determined and position compensation can be carried out. The proposed position correction method doesn't require additional hardware circuit and can be easily implemented. The validity of the proposed position compensation method is verified through several experiments.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1989년도 추계학술대회 논문집 학회본부
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• pp.5-9
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• 1989

In this paper, while 2-or 3-phase induction motor is driven with balance and no noise driving at dynamic and steady state condition. Single-phase induction motor is driven with pulsating torque except specific driving point. So we analyze the reason of producing pulsating torque with the view of unsymmetring concept. These results are applied to the design of high efficincy, high quality single-phase induction motor.

• 제어로봇시스템학회논문지
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• 제21권10호
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• pp.910-916
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• 2015

A sensorless motor control scheme with conventional back-Electro Motive Force (EMF) sensing based on zero crossing point (ZCP) detection has been widely used in various applications. However, there are several problems with the conventional method for effectively driving sensorless brushless motors. For example, a phase mismatch of 30 degrees occurs between the ZCP and commutation time. Additionally, most of the motor speed/current controls are achieved based on a pulse width modulation (PWM) method, which generates significant noise that distracts the back-EMF sensing. Due to the PWM switching, the ZCP is not deterministic, and thus the efficiency of the motor is reduced because the phase transition points become uncertain. Moreover, the motor driving performance is degraded at a low speed range due to the effect of PWM noise. To solve these problems, an improved back-EMF detection method based on a differential line method is proposed in this paper. In addition, the proposed sensorless BLDC driver addresses the problems by using a variable voltage driver generated from a buck converter. The variable voltage driver does not generate the PWM switching noise. Consequently, the proposed sensorless motor driver improves 1) the signal-to-noise ratio of back-EMF, 2) the operation range of a BLDC motor, and 3) the torque characteristics. The proposed sensorless motor driver is verified through simulations and experiments.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2002년도 하계학술대회 논문집 C
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• pp.1518-1520
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• 2002

Purpose of this research compares best transfer speed about applied frequency and voltage using characteristic of $L_1-B_4$ mode and $L_1-B_8$ mode linear ultrasonic motor that use piezoelectric effect. By method of study, analyzed best transfer speed measuring and comparison load status that use actuality telephone card in $L_1-B_4$ mode linear ultrasonic motor and no-load status of $L_1-B_8$ mode linear ultrasonic motor. Experiment result is applied frequency(58.4Hz) in $L_1-B_4$ mode linear ultrasonic motor (load state) and the best transfer speed by 19.8[cm/s] at applied voltage(56V) point. Also, $L_1-B_8$ mode linear ultrasonic motor (no-load state) is best transfer speed by applied frequency(27.9kHz) and 32.96[cm/s] at applied voltage (50V) point.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2004년도 추계학술대회 논문집 Vol.17
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• pp.85-88
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• 2004

The piezoelectric ceramic is attached between 'L' type guide and 'L' type stator, This motor has rotary motion which is operated by longitudinal and bending mode. The basic structure of the two kinds of type motor that called one stator motor, two stator motor is same but we suggested a few parameters for considering their stator design and characteristics. As a result, the two stator type motor is much more useful than one stator type motor for hi-direction rotation.

• KIEE International Transaction on Electrical Machinery and Energy Conversion Systems
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• 제3B권4호
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• pp.159-164
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• 2003

In this paper, a three-dimensional finite element method and construction of equivalent-circuit for a linear ultrasonic motor are presented. The validity of three-dimensional finite element routine in this paper is experimentally confirmed by analyzing impedance of a piezoelectric transducer. Using this confirmed finite element routine, impedance and vibration mode of a linear ultrasonic motor are calculated. Elliptical motion of contact point between vibrator and rail of the linear ultrasonic motor is shown for determination of contact points. By using the finite element method and analytic equations, characteristics of the linear ultrasonic motor, such as thrust force, speed, losses, powers and efficiency, are calculated. The results are confirmed by experiment. Finally, equivalent circuit parameters of the linear ultrasonic motor are obtained using the three-dimensional finite element method and analytic equations.

• 전력전자학회논문지
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• 제6권6호
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• pp.498-505
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• 2001

본 논문은 PV어레이를 이용한 양수펌프 시스템의 전체적인 제어를 구상하는 제시하였으며, DC/DC 컨버터를 생략하기 위하여 BLDC 모터의 벡터제어를 이용하고 DC량과 AC량과 관계를 찾아내어 인버터만으로 PV 어레이의 최대출력점을 추적하였다. 기존의 최대출력점 제어기는 3상 인버터의 DC 링크단에 나타나는 전류리플로 인하여 제어기가 불안정하게 된다. 따라서 본 연구에서는 제어기의 불안정성을 보완하기 위해 BLDC 모터의 $i_qs$ 전류를 이용한 MPPT(Maximum Power Point Tacker) 제어 알고리즘을 구성하였다. 이러한 제어기의 우수함을 입증하기 위하여 J. A Domfnguez가 비동기모터에 적용한 제어방식을 BLDC 모터에 적용한 결과와 본 논문에서 제시한 제어방식을 시뮬레이션 및 실험을 통하여 비교 검토하고 하였다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2004년도 하계학술대회 논문집 C
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• pp.1649-1651
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• 2004

The piezoelectric ceramic is attached between 'L' type guide and 'L' type stator. This motor has rotary motion which is operated by the travelling wave. The basic structure of the two kinds of type motor that called one stator motor, two stator motor is same but we suggested a few parameters for considering their stator design and characteristics. As a result, the two stator type motor is much more useful than one stator type motor for bi-direction rotation.