• Title/Summary/Keyword: Motor Point

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The Effect on Activity of Cerebral Cortex by Key-point Control of The Adult Hemiplegia with fMRI (fMRI를 이용한 성인 편마비의 항조절점 운동이 대뇌피질의 활성화에 미치는 효과)

  • Lee Won-Kil
    • The Journal of Korean Physical Therapy
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    • v.15 no.3
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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.

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Validation of the Simplified Motor Score for the Triage after Traumatic Brain Injury (두부 외상 환자의 중증도 평가 시 단순운동점수의 유용성)

  • Lee, Sang Kyong;Ryoo, Hyun Wook;Park, Jung Bae;Seo, Kang Suk;Chung, Jae Myung
    • Journal of Trauma and Injury
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    • v.21 no.2
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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.

Position Correction Method for Misaligned Hall-Effect Sensor of BLDC Motor using BACK-EMF Estimation (역기전력 추정법을 이용한 브러시리스 직류 전동기의 홀센서 상전류 전환시점 보상 방법)

  • Park, Je-Wook;Kim, Jong-Hoon;Kim, Jang-Mok
    • The Transactions of the Korean Institute of Power Electronics
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    • v.17 no.3
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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.

A Study on the Performance Analysis of Single-Phase Induction Motor Considering Asymmetrical Concept (비대칭성개념(非對稱性槪念)을 고려한 단상전원용유도전동기(單相電源用誘導電動機)의 특성해석(特性解析)에 관한 연구(硏究))

  • Lee, Il-Chun;Kim, Chul-Woo;Hwang, Young-Moon
    • Proceedings of the KIEE Conference
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    • 1989.11a
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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.

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Design of Sensorless BLDC Motor Driver Using Variable Voltage and Back-EMF Differential Line (가변 전압기와 역기전력 차동방식을 이용한 센서리스 BLDC 전동기 드라이버 설계)

  • Lee, Myoungseok;Kong, Kyoungchul
    • Journal of Institute of Control, Robotics and Systems
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    • v.21 no.10
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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.

Comparison of Characteristics between $L_1-B_4$ mode and $L_1-B_8$ mode Ultrasonic Motors ($L_1-B_4$모드와 $L_1-B_8$모드 초음파 선형 전동기의 특성 비교)

  • U, Sang-Ho;Kim, Dong-Yeon;Kim, Jin-Soo
    • Proceedings of the KIEE Conference
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    • 2002.07c
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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.

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Design and Analysis of a L shape two touch point ultrasonic rotary motor (L형 2타점 회전모터의 설계와 해석)

  • Kim, Sung-Hyun;Park, Tae-Gone
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2004.11a
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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.

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Analysis of Ultrasonic Linear Motor Using the Finite Element Method and Equivalent Circuit

  • Park, Jong-Seok;Joo, Hyun-Woo;Lee, Chang-Hwan;Jung, Hyun-Kyo
    • KIEE International Transaction on Electrical Machinery and Energy Conversion Systems
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    • v.3B no.4
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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.

MPPT Control of PV Water Pumping Using BLDC Motor-Inverter (BLDC 모터용 인버터를 이용한 PV 양수펌프의 MPPT 제어)

  • 김성남;백승길;조정민;이승환;오봉환;이훈구;한경희
    • The Transactions of the Korean Institute of Power Electronics
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    • v.6 no.6
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    • pp.498-505
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    • 2001
  • This paper shows how to design a global control of water pumping system using PV array, and tracked maximum power point of PV array only the inverter using the vector control of BLDC motor, and finding the relationships among the DC magnitudes and AC ones in order to omit the DC/DC converter. Conventional MPPT controller was unstable of reason of the ripple-current of DC link in three-phase invertor. Thus, in this paper the control algorithm of BLDC motor using $i_qs$ current is composed to improve the insecurity of conventional MPPT controller To prove the excellence of the proposed method, the contents of this paper is analyzed by means of simulation and testing for the results applying the method that J. A Domfnguez had applied to asynchronous motor to BLDC motor and that of the proposed method in this paper.

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Design and Analysis of a L shape two touch point ultrasonic rotary motor (L형 2타점 회전모터의 설계와 해석)

  • Kim, Sung-Hyun;Kim, Hang-Sik;Park, Tae-Gone
    • Proceedings of the KIEE Conference
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    • 2004.07c
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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.

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