• 한국정밀공학회지
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• 제33권10호
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• pp.789-796
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• 2016

The weight of an antenna system pointing satellite on the mobile platform is restricted by the weight limit of the mobile platform. The maximum power of the actuator driving the antenna system is thus limited because a high power actuator needs a heavier weight. Thus, a drive system is designed to have a low torque requirement by reducing the gravitational torque depending on gravity or acceleration of the mobile platform, including vibration, shock, and accelerated motion. To reduce the gravitational torque, the mathematical model of the gravitational torque is preferentially obtained. However, the method to directly estimate the mathematical model in an antenna system has not previously been reported. In this paper, a method is proposed to estimate the gravitational torque as a mathematical model in the antenna system. Additionally, a method is also proposed to calculate the optimal weight of the balancing weight to compensate for the gravitational torque.

• 한국게임학회 논문지
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• 제20권1호
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• pp.13-22
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• 2020

본 연구는 가상 물체의 무게감을 사용자에게 전달하여 몰입감 있는 가상현실 경험을 제공하는 컨트롤러에 관한 것이다. 무게감 전달의 수단으로 컨트롤러 내 무게 중심의 위치를 변화시키면 모멘트의 크기가 변화하는 개념을 활용하였다. 사용자가 무게차를 인지하는 무게 중심의 최소이동거리를 알아보기 위해 무게 중심의 위치를 변경할 수 있는 실험 장치를 제작하여 실험을 수행하였다. 그 결과, 시작 자극의 위치와 무관하게 약 5cm의 무게부 거리 차에서 두 물체 간의 무게 차이를 인지하는 것으로 나타났다. 향후 이러한 실험 결과를 반영하여 모멘트 변화에 따른 무게 인지의 최소이동거리 역치 값을 찾는 실험을 수행할 것이다.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2009년도 추계학술대회 논문집
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• pp.391-394
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• 2009

Asymmetrical and unbalanced features such as rotor blade of helicopter, actuator of hard-disk in personal computer are usually manufactured with composite materials. In this case, mass distributions and center of gravity of the parts are important because of their static balancing. Therefore in the manufacturing processes, it is needed to check out the exact data of weight and gravity center. In this study, it has been studied experimentally the balancing of laminated rotor blade by using multiple-point weighing method and lab-view system.

• 대한의용생체공학회:의공학회지
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• 제27권5호
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• pp.245-249
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• 2006

The aim of this study is to design and develop the gait rehabilitation equipment that judge patient's movement of his/her center of gravity using pressure sensors, and to aid hemiplegic patients to balance themselves using an automatic stepper that changes the patient's center of gravity. It is hard to bear the weight on the affected side for hemiplegic patients. The gait rehabilitation equipment detects the footing phase of hemiplegic patient during training and moves the unaffected footing side of the stepper up and moves the affected footing side down simultaneously so that the patient's center of gravity can shift from unaffected side to affected side. The gait rehabilitation system was developed and applied for hemiplegic patients during exercise. Eight hemiplegic patients and one normal adult were studied. The developed gait rehabilitation system could judge not only the normal adult's intention but also the patient's intention to move his/her center of gravity. Even though the most of hemiplegic patients exercised in automatic mode and a few hemiplegic patients exercised in manual mode, the developed gait rehabilitation system can aid the hemiplegic patients to train more easily.

• 전자공학회논문지
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• 제53권4호
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• pp.149-155
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• 2016

본 논문에서는 운전자의 체중 이동을 활용한 메카넘 휠 기반 전방향 전동 보드 제어 방법을 제안한다. 운전을 위한 별도의 운전 장치를 사용하지 않으며, 다수의 센서를 활용하여 측정한 체중 분포로부터 무게 중심의 위치를 구하여 전방향 전동 보드의 병진 운동과 회전 운동의 3 자유도 운전 명령을 생성한다. 체중 이동은 운전 명령으로 반영됨과 동시에 관성력을 극복하기 위한 운전자의 동작과 일치하여 직관적인 장점이 있다. 전체 제어 구조를 제시하며, 실험에 적용하여 제안된 방식의 타당성을 확인한다.

• 대한임베디드공학회논문지
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• 제12권5호
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• pp.311-318
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• 2017

A reduced order observer is developed for depth control of a hybrid underwater glider which combines the good aspects of a conventional autonomous underwater vehicle and a underwater glider. State variables include the center of gravity of the robot and the weight of the buoyancy bag, which can not be directly measured. By using the mathematical model and available information such as directional velocities, accelerations, and attitudes, we developed a Luenberger's reduced order observer to estimate the center of gravity and the buoyancy weight. By simulations using Matlab/Simulink, the efficiency of the proposed observer is shown, where a LQR controller using full state variables is adopted as a depth controller.

• 한국산업융합학회 논문집
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• 제27권1호
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• pp.229-237
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• 2024

The logistics industry is converging with digital technology and growing into various logistics automation systems. However, inspection and loading/unloading, which are mainly performed in logistics work, depend on human resources, and the workforce is shrinking due to the decline in the productive population due to the low birth rate and aging. Although much research is being conducted on the development of automated logistics systems to solve these problems, there is a lack of research and development on load stacking stability, which has the potential to cause significant accidents. In this study, loading boxes with various sizes and positions of the center of gravity were set up, and a method for stacking that with high stability is presented. The size of the loading box is measured using a depth camera. The loading box's weight and center of gravity are measured and estimated by a developed device with four loadcells. The measurement error is measured through various repeated experiments and is corrected using the least squares method. The robot arm performs load stacking by determining the target position so that the centers of gravity of the loading boxes with unbalanced masses with a random sequence are transported in alignment. All processes were automated, and the results were verified by experimentally confirming load stacking stability.

• 한국조경학회지
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• 제33권4호
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• pp.97-107
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• 2005

This study was carried out to construct accurate and scientific system of assessment indicators in selection of National Trust conservation areas, which was new concept of domestic environment movement and offer the raw data of new analytic method by introducing the fuzzy theory and weight for overcoming the uncertainty of ranking decision. To transform the Likert's scale granted to assessment indicators into the type of triangular fuzzy number(a, b, c), there was conversion to each minimum(a), median(b), and maximum(c) in applying membership function, and in using the center of gravity and eigenvalue, there was to decide the ranking. The rankings of converted values applied a mean importance and weight were confirmed that they were generally changed. Therefore, the ranking decision was better to accomplish objective and rational ranking decision by applying weight that was calculated in grouping of indicator than to judge the singular concept and to be useful in assessment of diverse National Trust site. In the future, because AHP, which was general method of calculating weight, was lacked, there was to understand the critical point to fix a pertinent weight, and to carry out the study applying engineering concept like fuzzy integral using $\lambda-measure$.

• 한국학교수학회논문집
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• 제17권4호
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• pp.771-804
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• 2014

'무게중심'의 개념은 현재 초등교과영역에서 처음 등장하여 대학의 수학과 물리학, 공학 분야 등 폭넓게 응용되고 있지만 실제 교육은 실생활과 유리된 이론수업의 형태가 대부분이었다. 2013년 '${\bigcirc}{\bigcirc}$대학교 과학영재교육원'에서 영재학생들을 대상으로 '무게중심 확인 융합 프로그램'을 개발하였고, 본 연구에서는 이 프로그램을 수준별 수업으로 재구성하여 비영재학생들에게 적용시켜 그 효과성을 분석하고자 한다. 물체의 빈 공간이나 물체 밖에 무게중심이 존재하는 경우를 확인하는 실험 등 새로운 과정을 포함하였으며, 무게중심을 구할 때 핵심이 되는 지렛대의 원리에서 지렛대의 무게를 고려한 계산 방식을 제시하여 보다 실제적으로 개념에 다가갈 수 있도록 하였다. 초 중 고등학교 학생 총 65명을 대상으로 기존 8차시 프로그램을 4차시로 재편성하여 적용하였고, 수업 후 설문과 토론, 인터뷰 등을 통하여 분석한 결과, 학생들은 정밀한 오차분석 등의 과정을 통하여 수준 높은 성공의 경험을 하였다.

• 패션비즈니스
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• 제28권1호
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• pp.83-97
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• 2024

A plantar pressure mat with visual notifications was developed to confirm whether individuals can effectively balance themselves and correct imbalances. The sensor-embedded mat was made with a commercial yoga mat, and was tested on seven working women in their 30s to determine plantar pressure distribution when standing and squatting, and if they could recognize and correct imbalances with visual feedback. The study found that visual notifications significantly changed the plantar pressure ratio of the forefoot and hindfoot, as well as the left and right foot plantar pressure ratio. Without notifications, the center of gravity was more concentrated in the rear foot than the forefoot in both standing and squatting positions. Visual notifications showed that the center of gravity, which was largely focused on the rear foot, was distributed to the forefoot, resulting in a more evenly distributed center of gravity throughout the sole. For the change in left and right plantar pressure, the weight that was largely loaded on the left side was distributed to the right foot through the visual notification mat, confirming a more balanced plantar pressure.