• 제어로봇시스템학회:학술대회논문집
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• 2005.06a
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• pp.93-97
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• 2005

This paper proposes a design of stepper motor control in microstep driven mode using FPGA (Field Programmable Gate Array) for hardware implementation. The methods to drive stepper motor in microstep excitation mode are to control of the controlling currents in each phase windings of stepper motor with reference signals. These reference signals are used for controlling the current levels, the required variation of current levels with rotor position can be obtained from the ideal linear or sinusoidal approximations to the static torque-displacement ($T-{\theta}$) characteristic curve. In addition, the hardware implementation of stepper motor controller can be designed uses VHDL (Very high speed integrated circuits Hardware Description Language) and synthesis using an Altera FPGA, FLEX10K family, EPF10K20RC240-4 device as target technology and use MAX+PlusII program for overall development. A multi-stack variable-reluctance stepper motor of Sanyo Denki is used in the experiments.

• PNF and Movement
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• v.8 no.3
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• pp.27-37
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• 2010

Purpose : The aim of this study was to investigate the effects of stepper exercise using lower extremity patterns of PNF(Proprioceptive neuromuscular facilitation) on ankle muscle strength and balance ability of females in their twenties. Method : Twenty subjects participated in this experiment were carried out the exercise program dose of 5 days per week for 2 weeks. They were divided into two groups; using twist stepper group(lower extremity patterns of PNF group, n=10) and using straight stepper group(n=10). The effects of twist stepper and straight stepper were evaluated by measurements of normal standing(NSEO, NSEC), and dynamic type 1 and dynamic type 2, respectively. For each case, the experimental data were obtained about static balance in 3 items : mean X speed, mean Y speed and velocity moment, that of dynamic balance in 4 items : mean X speed, mean Y speed, time, distance. Results : The results of this study were as follows; 1) In straight stepper group, the statistically significants were significants were shown on right/left ankle muscle strength in case of dorsi-flexion. 2) In twist stepper group, the statistically significants were significants were shown on right/left ankle muscle strength in case of dorsi-flexion. 3) In straight stepper group, the statistically significants were significants were shown on right ankle muscle strength in case of plantar-flexion. 4) In twist stepper group, the statistically significants were significants were shown on right/left ankle muscle strength in case of plantar-flexion. Conclusion : The above results revealed that twist stepper exercise using lower extremity patterns of PNF was more effective than straight stepper exercise for improving the ankle muscle strength.

• PNF and Movement
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• v.7 no.3
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• pp.7-16
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• 2009

The purpose of this study was to investigate the effects of plantar flexion exercise and stepper on the balance ability in normal peoples. Twenty subjects participated in this experiment were carried out the program on 6 weeks plantar flexion exercise and stepper. They were divided into two groups; plantar flexion group(plantar flexion exercise group, n=10) and stepper group(using stepper group, n=10). The effects of plantar flexion exercise and using stepper were evaluated by measurements of normal standing(NSEO, NSEC), and semitandom standing and dynamic type 1 and dynamic type 2, respectively. For each case, the experimental data were obtained about static balance in 3 items: mean X speed, mean Y speed and velocity moment, that of dynamic balance in 2 items: mean X speed, mean Y speed. The results of this study were as follows; 1. In plantar flexion exercise group, the statistically significants were shown on X, Y speed and velocity moment in the case of NSEO, NSEC, semitandom standing, and on X, Y speed in the case of dynamic type 1, dynamic type 2. 2. In using stepper group, the statistically significants were shown on X, Y speed and velocity moment in the case of NSEO, NSEC, semitandom and on only X, Y speed in the case of dynimic type 1, dynaimic type 2. 3. There was a statistically significant similar on all about case. however, the statistically difference were not shown with intergroup. The above results revealed that plantar flexion exercise and using stepper was effective for improving the balance ability.

• The Journal of Korean Physical Therapy
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• v.25 no.6
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• pp.393-398
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• 2013

Purpose: The purpose of this study was to compare muscle activation patterns of lower extremities in stroke patients during stepper climbing, stair-up, and level-ground gait conditions by surface electromyography (EMG). Methods: Subjects included 19 hemiplegic patients comprehensive rehabilitation center for inpatients with stroke. Surface EMG was used to measure the subjects' medial gastrocnemius (GCM), tibialis anterior (TA), biceps femoris (BF), and rectus femoris (RF) activity as they took six steps during stepper climbing, stair-up, and level-ground gait conditions. Results: There was no significant difference in the BF or RF muscle activity for the stepper climbing, stair-up, and level-ground gait conditions. However, there were significant differences in the medial GCM and TA muscle activity between each condition on the patients' hemiplegic side(p<0.05). There was significant difference in the medial GCM, TA, RF, and BF muscle activity between each condition on the patients' non-hemiplegic side (p<0.05). Conclusion: As a result, the overall muscle activity during the level-ground gait was higher than the stair-up condition, and the muscle activity during the stair-up condition was higher than the muscle activity during the stepper climbing condition. As one of the many methods used for gait training, we suggest that the stepper exercise could be applied at an earlier stage in the gait training process.

• IE interfaces
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• v.10 no.1
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• pp.1-13
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• 1997

반도체 Wafer Fabrication 공정은 무수한 공정과 복잡한 Lot의 흐름 등으로 다른 제조 형태에 비해 효율적인 관리가 대단히 어려운 부문이다. 본 연구는 반도체 Fab을 대상으로 주어진 생산 소요량과 목표 공기를 효율적으로 달성하기 위한 Shift 단위의 생산 일정계획을 대상으로 하였다. 특히, 전 공정 및 장비를 고려하기보다는 Bottleneck인 Photo 공정의 Stepper를 중심으로, 공정을 Layer단위로 묶어, 한 Shift에서 어떻게 Stepper를 할당하고 생산계획을 할 것인가를 결정하기 위한 2단계 방법론을 제시하고, Stepper 할당 및 계획에 필요한 3가지 알고리즘들을 제시하였다. 이 기법들을 소규모의 예제들에 대해 적용한 결과와 최적해와의 비교를 통하여 그 성능을 평가하였다.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.31A no.7
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• pp.69-75
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• 1994

A very fine pattern formation process using double exposure is investigated, which can overcome the resolution limit of optical wafer stepper. The very fine pattern can be obtained by moving the edge profile of large pattern by means of moving the stepper stage. The simulation results show that the light transmittance decrease bellow 9%, and the contrast increase to 16.6% for the 0.3$\mu$m photoresist pattern exposeed by the double exposure using i-line wafer stepper. And the experimental results show that fine photoresist pattern as short as 0.2$\mu$m can be obtained without a loss of photoresist thickness. Also, it proves that the depth of focus for 0.3$\mu$m pattern is longer than $1.5\mu$m. And, the very fine negative photoresist pattern was formmed by using the double exposure technique and the image reversal process.

• Journal of Institute of Control, Robotics and Systems
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• v.20 no.3
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• pp.323-332
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• 2014

Stepper motor is widely used in positioning applications due to its durability and high torque to inertia ratio as well as low cost and ability to be easily controlled with open-loop. Due to increased resolution of position control and improved stability of motion control, microstepping has drawn attention in industry since it was introduced in 1970s. With the increase in computational power and decrease in cost of embedded processors in recent years, drives and control systems for stepper motors have become more sophisticate than ever. Thus, closed-loop control methods have been developed to improve the performance of the stepper motors. In this paper, we review not only basic principles of conventional control methods used for stepper motors but also that of microstepping control. In addition, we surveyed recent development in nonlinear control methods applied to stepper motors. The nonlinear control methods are presented in the view of Lyapunov stability. Nonlinear torque disturbance observer, sliding mode control, and nonlinear phase compensation are also presented.

• The Korean Journal of Food & Health Convergence
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• v.7 no.6
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• pp.17-24
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• 2021

This study investigates the exercise-physiological changes in stages through the movement of the automatic stepper and to analyze the usefulness of the automatic stepper. For 18 male university students, out of 10 levels, 5 level and 10 level of automatic stepper exercise were performed. At each 10, 20, 30 minutes during exercise, 5 and 10 minutes after exercise stop the subjects were examined to analyze the changes in energy consumption after minutes, respiratory exchange rate, heart rate, oxygen consumption per body weight, METs, cumulative energy consumption, and lactic acid to verify the usefulness of the automatic stepper. The mean and standard deviation were calculated using the SPSS, and one-way ANOVA with repeated measure was performed to verify the difference in the mean between time periods. The LSD method was used for the post-hoc test, and the significance level was set to α = .05. There were no significant changes in both 5 and 10 level, but the cumulative energy consumption over time increased significantly. In addition, as a low-intensity exercise intensity is shown, a low increase in lactic acid indicated a safe exercise level. In future studies, in-depth studies of various variables through regular exercise programs are needed for those who need safe exercise.

• Proceedings of the Optical Society of Korea Conference
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• 1996.09a
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• pp.24-24
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• 1996

• ETRI Journal
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• v.11 no.4
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• pp.139-149
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• 1989

Excimer laser를 이용한 투영노광기술은 '80년대 초 $0.5\mum$ 이하의 패턴 형성에 시도된 이래 점진적인 발전을 이루어 왔으며 기존 광노광기술의 연장선상에서 64M bit DRAM 제조를위한 핵심 노광기술이 될 것이다. 본 논문에서는 차세대 노광장비로서의 excimer stepper가 갖는 중요성을 고찰하고 대량생산을 위한 노광장비의 개발방향을 제시하였다. 먼저단파장화에 의한 투과도 저하로 인하여 발생하는 투영광학계의 문제점을 살펴보고 이에 따른 광원의 요구조건을 도출하였다. 그리고excimer stepper를 광원, 조명계, 투영계, 정렬계, stage계 및 제어계등 기능별로 분류한 후 각각의 문제점 및 설계조건을 제시하였다.