• Journal of Biosystems Engineering
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• 제9권2호
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• pp.37-47
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• 1984

Using the soil bin systems, this study was carried out to analyze the effects of the angular and tilling speed of the rotary shaft with the edge curves which were $30^{\circ}$ and $40^{\circ}$, and the edged blade which were single and double, on the torque requirement of rotary tillage. In the analyses, we developed the mathematical models for the torque requirments of rotary tillage, and analyzed the optimum conditions of each variable for the minimum tillage torque requriements. The results of the study were summarized as follows. 1. The required tilling torque by one rotary blade has the minimum value when the tilling speed of the rotary blade was low, and the revolution of the rotary blade was fast, in general. 2. The torque requirements of single edged blade was decreased to about 81% in comparing with that of double edged blade of which the edge curved angle was $40^{\circ}$ and the tilling speed was 29.40 cm/sec. But, for the mean values, the maximum torque requirements were decreased to 45%, and the mean torque requirements were decreased to 35%. 3. For the edge curved angle, the torque requirements of ${\theta}=40^{\circ}$ were 48% more than that of ${\theta}=30^{\circ}$ in the maximum tilling torque in case that the rotary blade were double edged blade. but, there was not a difference when the rotary blades were single edged blade. The mean tilling torques of ${\theta}=40^{\circ}$ were 6% more when the rotary blade was double edged blade, and were 11% less at single edged blade, than that of ${\theta}=30^{\circ}$. 4. In order to reduce the torque requirements for tilling, the optimum revolutions of the rotary shaft were analyzed as that 204-240 rpm for the double edged blade and 280-320 rpm for the single edged blade.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1994년도 하계학술대회 논문집 A
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• pp.328-330
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• 1994

The Ultrasonic motor(USM) has many good characteristics such as high torque at low speed range, large holding torque based upon frictional force, high speed response, flexible free ferns, compactness in size, low magnetic noise and silentness in motion. Because of having low speed rotation, USM is good as an actuator of a small size direct drive (DD) manipulator. The acturators for the DD manipulators must have good controllability on the speed and torque from zero to maximum value continuously. New method was developed for speed and torque control by the phase difference control of the two-phase driving signals of the motor. Then rule adjustable compliant and dumped motion was realized on the output shaft of the motor by PD control of the output shaft angle.

• 대한치과보철학회지
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• 제44권4호
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• pp.432-442
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• 2006

Statement of problem: One of common problems associated with dental implant is the loosening of abutment screws that retain the implants. Purpose : This study was performed to investigate the influence of abutment screw length and repeated tightening on screw loosening in dental implant. Material and method: Forty nine Hexplants (13mm length, 4.3mm diameter, Ti grade IV, Warantec. Co. Ltd. Seongnam, Korea) and cementation type abutments(straight abutment) and abutment screws (0.4mm/pitch) were divided into 7 groups, depending on abutment screw length. Each implant and abutment was tightened to 30Ncm by torque controller(MGT50, MARK-10 Inc., USA) and the removal torque values were measured during 10 consecutive closure/opening trials. Results and Conclusion: The results of comparing the removal torque value are as follows : 1. There is no significant difference in the removal torque value between groups in 10 consecutive closure/opening trials (p = 0.97). 2. If the fractured abutment screw is engaged in longer than 2.425 thread length, there is no significant difference in the preload between the fractured abutment screw and the new abutment screw when both are equally tightened to 30 Ncm. 3. The removal torque value in the 1st trial(24.510 Ncm) was lower than that in the 2nd, 3rd, 4th, 5th, 6th, 7th trials and the removal torque value in the 2nd trials(25.551 Ncm) was maximum and was decreased in 1311owing trials. The removal torque value in the 1st trial was significantly lower than that in the 2nd, 3rd, 4th trials and was significantly higher than that in the 8th, 9th, l0th trials(p<0.05). 4. In the 2nd, 3rd, 4th, 5th, 6th, 7th trials, the abutment screw was mainly influenced by settling effect and the higher preload was obtained In the 8th, 9th, l0th trials, the abutment screw was mainly influenced by adhesive wear and the progressively lower preload was obtained.

• 한국정밀공학회지
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• 제20권8호
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• pp.185-193
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• 2003

The modular self-wiping co-rotating twin screw extruder (SWCOR) has become the most important of twin screw machines. Screw design is one of the most important factors in determining performance of screw extruder. The screw flight and screw channel geometry of SWCOR is determined by the screw diameter, centerline distance, helix angle, and flights number. The maximum allowable throughput rate on a twin screw extruder is determined by a combination of free volume and available specific torque. In this paper we designed geometrical parameters of extruder screw and presented optimal specific torque value in K=1.55, and then developed screw design program for the screw cutting by the use of JAVA API in the twin screw extruder.

• 한국조명전기설비학회:학술대회논문집
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• 한국조명전기설비학회 2007년도 추계학술대회 논문집
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• pp.313-318
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• 2007

Interior permanent magnet synchronous motor(IPMSM) has become a popular choice in electric vehicle applications, due to their excellent power to weight ratio. This paper proposes maximum torque control of IPMSM drive using adaptive fuzzy neural network controller and artificial neural network(ANN). This control method is applicable over the entire speed range which considered the limits of the inverter's current and voltage rated value. For each control mode, a condition that determines the optimal d-axis current $i_d$ for maximum torque operation is derived. This paper considers the design and implementation of novel technique of high performance speed control for IPMSM using Adaptive-FNN controller and ANN controller. The hybrid combination of neural network and fuzzy control will produce a powerful representation flexibility and numerical processing capability. Also, this paper reposes speed control of IPMSM using Adaptive-FNN and estimation of speed using ANN controller. The back propagation neural network technique is used to provide a real time adaptive estimation of the motor speed. The proposed control algorithm is a lied to IPMSM drive system controlled Adaptive-FNN and ANN controller, the operating characteristics controlled by maximum torque control are examined in detail. Also, this paper proposes the analysis results to verify the effectiveness of the Adaptive-FNN and ANN controller.

• 조명전기설비학회논문지
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• 제21권5호
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• pp.32-43
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• 2007

IPMSM은 하중에 비하여 고출력으로 인하여 전기자동차에 널리 보급되고 있다. 본 논문은 적응 학습 퍼지-신경회로망과 ANN을 이용한 IPMSM드라이브의 최대토크 제어를 제시한다. 이러한 제어 방법은 인버터의 정격전류 및 전압값의 범위를 고려한 전속도 영역에 적용 된다. 본 논문은 적응학습 퍼지-신경회로망을 이용하여 IPMSM의 속도제어와 ANN을 이용하여 속도를 추정을 제시한다. 신경회로망의 역전파 알고리즘은 전동기 속도의 실시간 추정을 제시하는데 사용된다. 제시된 제어 알고리즘은 적응학습 퍼지-신경회로망과 ANN 제어기를 IPMSM 드라이브에 적용된다. 최대토크에 의해 제어된 동작 특성은 세부적으로 실험한다. 또한 본 논문은 적응 학습 퍼지 신경회로망과 ANN의 효과를 결과 분석을 통해 제시한다.

• 대한치과보철학회지
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• 제33권2호
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• pp.335-353
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• 1995

The purpose of this study was to the determine the optimal torques values to tighten the retaining screw. 3-different implant system tested were as follows : Branemark implant system$(3.75mmD{\times}100mm)$, Steri-Oss implant system$(3.8mmD{\times}10mm)$. One fixtures of each implant system was mounted into the epoxy resin block and abutment/superstructure complex was constructed. Eighty dental college students(male : 40, female : 40) of Chosun University were selected and were asked to tighten the retaining screws. Abutment/superstructure complex of each implant system was tightened to the maximum torque by use of hand-held screw driver, and then torque value was measured with torque value was measured with torque driver(Tohnichi torque driver, model 20 FTD, Tohnichi MFG, Co., LTD., Tokyo, Japan). Abutment/superstructure complex of each implant system was titghtened to each torque of 10 N-cm, 20 N-cm and 30 N-cm, and then the dynamic load(vertical & diagonal load) was applied to the abutment / superstructure complex. The gap between abutment/superstrure in each implant system was measured with 3-dimensional measuring microscope(model No. 850, Germany). The results were as follow : 1. Torque values according to the individual subjects showed wide range. 2. Torque values according to sex showed statistical significant difference. Those are as follows : in case of male, $9.38{\pm}2.93$ N-cm ; incase of female, $7.80{\pm}2.25$ N-cm. 3. Torque values according t implant systems showed statistical significant difference. Those are as follows : in ase of Branemark implant system, $6.54{\pm}1.54$ N-cm : in ase of Steri-Oss implant system, $10.1{\pm}2.88$ N-cm ; in case of IMZ implant system, $9.18{\pm}2.17$ N-cm. 4. The more torque value of tightening screw was increased, the less the gap was after the vertical and diagonal loading. 5. The gap after the diagonal loading was greater than that after the vertical loading. 6. The magnitude of gap between abutment/superstructure in order of IMZ, Steri-Oss, Branemark implant system after the verical and diagonal loading. 7. The gap under the diagonal loading after applying 30 N-cm torque showed no statistical significant difference in cases of the Branemark system and the Steri-Oss implant system but it showed significant different in case of the IMZ implant system.

• Journal of Chest Surgery
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• 제54권3호
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• pp.186-190
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• 2021

Background: Pre-lifting of the sternum marked a major turning point in pectus excavatum repair. The author developed the crane technique in 2002 and successfully applied it to more than 2,000 cases using sternal wire stitching. However, blind sternal suturing limited the use of the wire-stitch crane. We propose a novel screw for sternal lifting as a new tool for the crane technique. Methods: We developed a screw system strong enough to withstand the pressure needed for sternum lifting. The screw was designed to have a broader thread to hold the bony tissue securely. The screw's sustaining power was tested using the torsion, driving torque, and axial pull-out tests in a polyurethane block and ex-vivo porcine sternum. Results: The screws were easily driven into the sternum, and the head of the screw was connectable to the table-mounted retractor. In the torsion test, the 2° offset torsional yield was 4.53 N·m (reference value, 1 N·m). In the polyurethane block driving torque test, the maximum torque was 0.98 N·m (reference value, 0.70 N·m). The axial pull-out test was 446 N (reference value, 100 N). The maximum pull-out resistance in the ex-vivo porcine sternum model was 1,516 N. Conclusion: The screw crane was strong enough to sustain the chest wall weight to be lifted. Thus, the screws could effectively replace the sternal wire stitching in crane pre-lifting of the sternum. We expect that application of the screw-crane will be easy and that it will improve the safety and success rate of pectus repair surgery.

• 대한치과교정학회지
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• 제38권1호
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• pp.5-12
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• 2008

교정용 미니스크류의 원추 형태가 식립 후 시기별 안정성에 미치는 영향을 알아보기 위해, 시기별 제거 토오크 및 동요도와 조직시편분석을 시행하였다. 성견 6마리의 하악 협측골에 원통형과 원추형 교정용 미니스크류 (Biomaterials Korea, Seoul, Korea) 48개를 식립하고, 식립 시 식립 토오크와 동요도를 측정하고 3주, 12주 동안 교정력을 부여한 후, 제거 시 제거 토오크와 동요도를 측정하였다. 식립 토오크는 원통형 미니스크류에서 13.6 Ncm, 원추형 미니스크류에서 22.3 Ncm 로 원추형 미니스크류에서 높은 식립 토오크가 측정되었다 (p < 0.001). 식립 3주째 제거 토오크는 원통형 미니스크류에서 5.7 Ncm, 원추형 미니스크류에서 9.1 Ncm 로 유의한 차이가 관찰되었다 (p < 0.05). 식립 12주째 원추형 미니스크류의 제거 토오크는 3.6 Ncm 로 유의하게 감소하여 (p < 0.05) 원통형 미니 스크류의 4.2 Ncm 와 유의한 차이를 보이지 않았다. 이상의 결과로 미니스크류의 원추 구조는 식립 토오크를 유의하게 증가시켜 식립 후 3주간 안정성에 도움이 되었으나, 12주 후 안정성에 있어서는 원통형 미니스크류와 유사하였음을 시사한다.

• 한국조명전기설비학회:학술대회논문집
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• 한국조명전기설비학회 2008년도 추계학술대회 논문집
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• pp.307-310
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• 2008

This paper is proposed the vector control of 3-phase induction motor drive system by photovoltaic generation. For performance of vector control using a current control voltage source inverter(CC-VSI). CC-VSI is controlled by torque and flux producing component of motor current, relating with current and voltage value of photovoltaic arrays at maximum power point that varies follow different level of insolation. The MPPT using a DC-DC converter controlled the duty cycle to track maximum power from PV under different insolation conditions. The simulation results are shown that the characteristics and performance of drive system, which varies as each conditions of light by expresses in voltage($V_{dq}$), current($I_{dq}$), speed of motor and torque.