• Transactions of the Korean Society of Automotive Engineers
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• v.20 no.4
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• pp.133-141
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• 2012

This study investigates structural and fatigue analyses of bike brake. Maximum equivalent stress of the model of mountain bike is 4 times as much as the model of general bike at static analysis. In cases of mountain and general bikes, maximum damage frequency at load of 'SAE bracket history' with the severest change of load becomes as much as 16 times than the most stable load of 'Sample history' among the nonuniform fatigue loads. In case of mountain bike, the possibility of maximum damage becomes 3% at the load of 'Sample history' with the average stress of 0 to $-3{\times}10^4$MPa and the amplitude stress of 0 to $10^4$MPa. In case of general bike, the possibility of maximum damage becomes 3% at the load of 'Sample history' with the average stress of 0 to $-0.8{\times}10^4$MPa and the amplitude stress of 0 to $0.2{\times}10^4$MPa. This stress state can be shown as 5 to 6 times more than the damage possibility of 'SAE bracket history' or 'SAE transmission'. The analysis result of this study can be effectively utilized for the safe design of bike brake.

• Proceedings of the Korea Information Processing Society Conference
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• 2015.10a
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• pp.1760-1762
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• 2015

이 연구의 유아용 세발자전거는 내리막길을 접했을 때를 인지하면 바퀴에 마찰을 주어 운동 에너지를 감소시켜 탑승하고 있는 아이의 안전을 지켜주고 블루투스를 이용하여 보호자 핸드폰으로 알림메시지를 전송한다. 한번 작동한 브레이크는 유아의 안전을 위하여 보호자의 핸드폰에서 작동을 해지할 때까지 해제되지 않는다.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2013.05a
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• pp.919-922
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• 2013

Currently, society thinks human-health is very important. As a result, the number of individual bikes is increasing. And bicycle accident rate is increasing every year. We have developed the safety-equipment utilizing a smartphone. Because, in order to reduce the rate of bicycle accidents. The working principle is that the connection between the bicycle and safety equipment with built-in Bluetooth chip. Information of bike-driving Is measured using a smartphone with built-in gyro sensor. I made an algorithm for specifying a direction by using the values of the gyro sensor. With this algorithm, it is possible to reduce the accident rate of the bicycle.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2012.05a
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• pp.9-10
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• 2012

• Proceedings of the KIPE Conference
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• 2014.07a
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• pp.245-246
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• 2014

본 논문에서는 외전형 영구자석 동기 전동기의 전기적 브레이크 동작 시에 발생하는 회생 에너지를 분석한다. 그리고 전류 정보 없이 전동기 속도 및 배터리의 전압만으로 회생 전력을 제어하는 방법을 제안한다. 후륜 허브 전동기를 가지는 자전거 프로토 타입을 제작하고, 제안하는 회생 제동 제어 기법을 적용한 실험을 통해 제안 기법을 검증한다.

• Transactions of the Korean Society of Automotive Engineers
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• v.23 no.3
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• pp.287-291
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• 2015

This study investigates the result of thermal stress analysis on disk rotor by classes at bike brake. In the analysis result of thermal deformation at the steady state, maximum deformations at models 1, 2 and 3 are 0.14347mm, 0.15823mm and 0.16028mm respectively. The deformation becomes larger as the field goes on from the center to the outside at disk rotor. As there are models 1, 2 and 3 in the order of maximum deformation, model 1 has safest among three models. In the analysis result of thermal stress at steady and transient states, there are models 1, 2 and 3 in the order of maximum stress. Model 1 becomes most excellent on strength and safety among three models. By using the analysis result of disk rotor model at bike disk, it is possible to design the model applied practically at the safe driving of bike.

• Transactions of the Korean Society of Automotive Engineers
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• v.22 no.5
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• pp.44-49
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• 2014

As expansion and contraction of bike disk brake are happened continuously by temperature at repeated urgent braking. In this study, 3 kinds of model are designed according to configurations of holes and thermal durabilities on bike disk brake are investigated by comparing 3 models through temperature and thermal analyses. Maximum thermal stress happened at the disk contacted with pad and the connection part fixing disk rotor. Instead of initial state, the temperature is uniformly distributed at transient state. As the area of hole at disk rotor face becomes wider, thermal stress becomes lower at the initial state. On the other hand, in case the number of holes increases, thermal stress becomes lower at the elapsed time of 100 seconds. The thermal durability of bike disk brake can be improved by applying this study result with configurations of holes.

• Proceedings of the KIPE Conference
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• 2014.07a
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• pp.425-426
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• 2014

본 논문은 전기자전거용 충전 기능이 내장된 양방향 부스트 컨버터 기반의 DC 모터 구동 회로를 제안한다. 추가 전력 단 구현 없이 배터리 충전 기능을 내장한 양방향 부스트 컨버터 기반의 DC 모터 구동회로로써 회로 부피 및 원가 저감이 가능하고 회생충전모터의 작동을 통해 자가발전을 유도함과 동시에 안정적인 브레이크 기능 유도가 가능하다. 제안한 회로의 이론적 분석을 행하고, 모의실험을 통하여 타당성을 검증하였다.

• Journal of Biomedical Engineering Research
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• v.28 no.6
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• pp.832-839
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• 2007

In this study, a new bicycle system was developed to improve muscular strength using the Magneto-Rheological(MR) rotary brake. The friction load of the MR rotary brake is adjusted according to muscle strength of the subjects. The characteristic of muscular strength was studied with various friction loads of MR rotary brake. The friction load was occurred with the current, applied to the MR. rotary brake. Experiments was composed of several cycling trials for various friction loads. In training programs involving muscle improvement, it is necessary to confirm muscle activity and fatigue. To measure the muscle activity and fatigue, EMG signals of rectus femoris (RF), biceps femoris (BF), tensor fasciae latae (TFL), vastus lateralis (VL), vastus medialis (VAS), gastrocnemius (GAS), tibialis anterior (TA) and soleus (SOL) muscles were collected with surface electromyography and analyzed into time and frequency domain. The experimental results showed that the muscle activity according to the applied current to the MR rotary brake was significantly different. The more the current was applied, the higher value of the integrated EMG (IEMG) was obtained. Especially, the magnitude of IEMG of the RF, BF, TFL and VL varied in direct proportion to the current. However, there was not significant in the median frequency as the cycling time continue.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.57 no.9
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• pp.1669-1673
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• 2008

A new cycle ergometer using a Magneto-Rheological (MR) rotary brake system has been developed for rehabilitation of hemiplegia patients to reduce uneven pedaling characteristics. For this purpose, a control method to adjust the resistance of the MR rotary brake in real time based on the magnitude of the muscular force exerted by the subject has been devised so that the mechanical resistance to the pedaling can be minimized when the affected leg was engaged for pedaling. A series of experiments were carried out with and without the engagement of this real-time control mode of MR rotary brake at different pedaling rate to find out the effect of the real-time control mode. The characteristics of the pedaling for these specific conditions were analyzed based on the variations in angular velocities of the pedal unit. The results showed that the variations in the angular velocities were decreased by 42.9% with the control mode. The asymmetry of pedaling between dominant and non-dominant leg was 19.63% in non-control mode and 1.97% in the control mode. The characteristics of electromyography(EMG) in the lower limbs were also measured. The observation showed that Integrated EMG(IEMG) reduced with the control mode. Therefore, the new bicycle system using MR brake with the real time control of mechanical resistance was found to be effective in recovering the normal pedaling pattern by reducing unbalanced pedaling characteristics caused by disparity of muscular strength between affected and unaffected leg.