• 산업융합연구
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• 제17권4호
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• pp.125-129
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• 2019

자전거를 이용하는 사람들의 수가 증가함에 따라 자전거 사고의 수도 증가하고 있습니다. LED 조명을 사용하면 자전거를 탈 때 자전거 사고를 최대 11 % ~ 44 %까지 줄일 수 있습니다. 자전거의 헤드라이트는 자전거 라이더의 반대쪽에 노출 효과를, 미등은 후면 자전거 라이더에 노출 효과를 제공하여 안전성을 향상시킵니다. 본 연구에서는 제어 버튼 신호에 응답하여 LED에 의한 방향 전환을 표시 할 수 있는 자전거 안전장치를 구현 하였다. 이 신호는 고정 된 시간 동안 자전거의 페달과 휠에 장착 된 LED 조명을 모듈 유형의 발광 또는 깜박임으로 만듭니다. 야간에 자전거를 타는 사람이 자전거를 타는 경우 LED를 사용하여 안전을 향상시킬 수 있는 페달의 자전거 보조 장치가 본 연구에서 개발되었습니다. 무선 통신 기술을 적용한 자전거 안전장치는 미래에 에너지, 환경 및 안전과 같은 사회적 문제를 해결하기 위한 대체 기술이 될 것으로 예상됩니다.

• 대한기계학회논문집A
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• 제38권4호
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• pp.393-400
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• 2014

본 논문에서는 실제 자전거 주행에 적용 가능한 자동변속장치를 개발하기 위하여 자전거용 변속장치 중 내장기어허브를 이용하여 자전거 자동변속장치를 개발하였다. 개발된 자동변속장치는 주행 중 페달rpm과 주행속도를 측정하여 자동변속을 수행하며, 최대심박수의 ~80% 부근에서 ~150W정도의 주행출력을 낼 수 있는 일반적인 이용자가 사용가능하도록 개발되었다. 서울시 한강변 자전거 주행로의 경사를 구현한 실내주행 실험결과 자동변속장치는 자전거 주행시 이용자의 페달rpm을 적정한 수준에서 유지하도록 변속을 수행하였으며, 자전거 이용이 서투른 이용자도 적정한 페달rpm을 유지하며 주행할 수 있었다.

• 한국운동역학회지
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• 제14권1호
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• pp.173-182
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• 2004

본 연구의 목적은 사이클 운동 시, 3가지 다른 길이의 페달 샤프트 (표준형, 5.08 cm, 10.16 cm)가 근육활동에 미치는 영향을 근전도 측정을 통해 비교 분석하는데 있다. 사이클링을 활동적으로 하는 여학생 5명을 피험자로 선택하여 대퇴지근(RF), 외측광근(VL), 내측광근(VM) 대퇴이두근(BF)을 표면전극을 사용하여 관찰하였다. 자료 분석을 위해 두 대의 S-VHS 카메라 (Panasonic Digital 5000)를 사용하여 사이클링 동작을 촬영하였다. 연구의 목적을 위해 각 조건에 대한 표준화된 평균 및 최대 근전도치가 계산되어졌다. 각각의 변인에 대해 페달 샤프트의 길이에 따른 근전도치의 차이점을 분석하기 위해 반복측정에 의한 일원변량분석을 사용하였으며, 통계적 유의성이 있을 경우 Newman-Keuls 사후검증을 실시하였다. 일반적으로 5.08 cm 길이의 페달 샤프트를 사용했을 경우 표준형의 페달 샤프트와는 다르게 모든 하지근의 적분 근전도치가 줄어드는 것으로 나타났다. 페달 샤프트의 길이가 길어짐에 따라 외측광근의 적분 근전도치가 통계적으로 유의하게 낮게 나타났고, 5.08 cm 길이에서 대퇴이두근의 적분 근전도치가 통계적으로 유의하게 낮게 나타났다. 페달 샤프트 길이에 따른 최대 근전도치의 통계적 유의성을 찾을 수 없었지만, 일반적으로 5.08 cm 길이의 페달 샤프트를 사용할 때 최대 근전도치가 가장 낮게 나타났다. 본 연구의 결과, 페달 샤프트의 길이가 하지근의 활동정도와 형태를 변화시킨다는 것을 알 수 있었으며, 하지관절의 부하에 영향을 미치는 것으로 사료되어진다. 이에 따라, 개인의 해부 구조학적인 면을 고려한 페달 샤프트의 길이 조절은 효율적이며 안정적인 사이클링 동작을 수행하는데 많은 도움이 될 수 있을 것이다.

• International Journal of Advanced Culture Technology
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• 제7권1호
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• pp.231-236
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• 2019

Background/Objectives: This paper proposes a dual mode feedback-controlled cycling system for children with spastic cerebral palsy to rehabilitate upper extremities. Repetitive upper limb exercise in this therapy aims to both reduce and analyze the abnormal torque patterns of arm movements in three- dimensional space. Methods/Statistical analysis: We designed an exercycle robot which consists of a BLDC motor, a torque sensor, a bevel gear and bearings. Mechanical structures are customized for children of age between 7~13 years old and induces reaching and pulling task in a symmetric circulation. The shafts and external frames were designed and printed using 3D printer. While the child performs active/passive exercise, angular position, angular velocity, and relative torque of the pedal shaft are measured and displayed in real time. Findings: Experiment was designed to observe the features of a cerebral palsy child's exercise. Two children with bilateral spastic cerebral palsy participated in the experiment and conducted an active exercise at normal speed for 3 sets, 15 seconds for each. As the pedal reached 90 degrees and 270 degrees, the subject showed minimum torque, in which the child showed difficulty in the pulling task of the cycle. The passive exercise assisted the child to maintain a relatively constant torque while visually observing the movement patterns. Using two types of exercise enabled the child to overcome the abnormal torque measured in the active data by performing the passive exercise. Thus, this system has advantage not only in allowing the child to perform the difficult task, which may contribute in improving the muscle strength and endurance and reducing the spasticity but also provide customizable system according to the child's motion characteristic. Improvements/Applications: Further study is needed to observe how passive exercise influences the movement characteristics of an active motion and how customized experiment settings can optimize the effect of pediatric rehabilitation for spastic cerebral palsy.

• Journal of Veterinary Science
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• 제23권6호
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• pp.68.1-68.8
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• 2022

Background: Studies on anesthetized dogs regarding pulse pressure variation (PPV) are increasing. The influence of respiratory rate (RR) on PPV, in mechanically ventilated dogs, has not been clearly identified. Objectives: This study evaluated the influence of RR on PPV in mechanically ventilated healthy dogs after hemorrhage. Methods: Five healthy adult Beagle dogs were premedicated with intravenous (IV) acepromazine (0.01 mg/kg). Anesthesia was induced with alfaxalone (3 mg/kg IV) and maintained with isoflurane in 100% oxygen. The right dorsal pedal artery was cannulated with a 22-gauge catheter for blood removal, and the left dorsal pedal artery was cannulated and connected to a transducer system for arterial blood pressure monitoring. The PPV was automatically calculated using a multi-parameter monitor and recorded. Hemorrhage was induced by withdrawing 30% of blood (24 mL/kg) over 30 min. Mechanical ventilation was provided with a tidal volume of 10 mL/kg and a 1:2 inspiration-to-expiration ratio at an initial RR of 15 breaths/min (baseline). Thereafter, RR was changed to 20, 30, and 40 breaths/min according to the casting lots, and the PPV was recorded at each RR. After data collection, the blood was transfused at a rate of 10 mL/kg/h, and the PPV was recorded at the baseline ventilator setting. Results: The data of PPV were analyzed using the Friedman test followed by the Wilcoxon signed-rank test (p < 0.05). Hemorrhage significantly increased PPV from 11% to 25% at 15 breaths/min. An increase in RR significantly decreased PPV from 25 (baseline) to 17%, 10%, and 10% at 20, 30, and 40 breaths/min, respectively (all p < 0.05). Conclusions: The PPV is a dynamic parameter that can predict a dog's hemorrhagic condition, but PPV can be decreased in dogs under high RR. Therefore, careful interpretation may be required when using the PPV parameter particularly in the dogs with hyperventilation.

• 한국전기전자재료학회논문지
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• 제37권1호
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• pp.106-111
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• 2024

A triboelectric nanogenerator is a promising energy harvester operated by the combined mechanism of electrostatic induction and contact electrification. It has attracting attention as eco-friendly and sustainable energy generators by harvesting wasting mechanical energies. However, the power generated in the natural environment is accompanied by low frequencies, so that the output power under such input conditions is normally insufficient amount for a variety of industrial applications. In this study, we introduce a non-contact rotational triboelectric nanogenerator using pedaling and gear systems (called by P-TENG), which has a mechanism that produces high power by using rack gear and pinion gear when a large force by a pedal is given. We design the system can rotate the shaft to which the rotor is connected through the conversion of vertical motion to rotational motion between the rack gear and the pinion gear. Furthermore, the system controls the one directional rotation due to the engagement rotation of the two pinion gears and the one-way needle roller bearing. The TENG with a 2 mm gap between the rotor and the stator produces about the power of 200 ㎼ and turns on 82 LEDs under the condition of 800 rpm. We expect that P-TENG can be used in a variety of applications such as operating portable electronics or sterilizing contaminated water.

• 한국자동차공학회논문집
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• 제17권2호
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• pp.1-9
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• 2009

A parking-assist system is defined that a driver adjusts vehicle velocity through brake pedal operation and parking-assist system controls the motion of the vehicle to follow a collision-free path. In this study, a motion control algorithm using Fuzzy inference is proposed to track a maneuvering clothoid parallel path. Simulations are performed under SIMULINK environments using MATLAB and CarSim for a vehicle model. As the vehicle model in MATLAB a bicycle model is used including lateral dynamics. The simulation results show that the path tracking performance is satisfactory under various driving and initial conditions.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2009년도 추계학술대회 논문집
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• pp.584-590
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• 2009

Since driving include compilcated actions that require a variety of abillity and cause extrme concentration or strain, divers tend to feel tired easiy. However, divers can't recognize fatigue degree by himself and accordingly the methods to measure quantitative fatigue degree exactly is quite difficult to be secured. In this study, the most efficient driving posture was suggested based on the analysis of quantitative muscular strength and fatigue degree according to posture. The driver whom we experimented included 9 commercial bus drivers. We also analyzed quantitative legs' muscular strength according te operating each pedal, left and right then we analyzed muscular strength and muscular fatigue degree according to driving pattern while driving commercial buses. And then we suggested the most efficient driving posture.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 1998년도 추계종합학술대회 논문집
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• pp.405-408
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• 1998

Generally, the principle function of simulator control loading system is to provide the pilot or student with the "feel" of the actual aircraft flight control systems during flight, taxing, and in malfunction. Flight control "feel" is the resistance felt by the pilot when moving a control stick or pedal, coupled with the amount of control surface deflection, and hence aircraft response, resulting from the input. Therefore, the control loading servo must be capable of performing to some general list of requirements derived from real aircraft control forces. In this paper, we deal with a $\mu-controller$ design for a control loading system of the flight simulator. For this, we derive a frequency response of the hydraulic system from the identification data and then design a controller using a $\mu-synthesis$ method. Under the same condition of simulation, $\mu-controller$ provides the superior performance than PID controller.than PID controller.

• 한국자동차공학회논문집
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• 제5권5호
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• pp.27-36
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• 1997

For the strength design of the brake system of a forklift truck, a procedure to calculate the internal forces acting on the system is presented in this paper. Vehicle dynamics, brake system kinematics, and internal force equilibrium analysis are integrated into the procedure. Design parameters such as stopping distance, maximum decceleration, and maximum torque generated by pedal force are considered in the vehicle dynamics, and geometric parameters of the brake system are considered in the brake system kinematics. With the two analysis results obtained, the internal forces acting in the brake system are finally calculated in the procedure.