• Journal of the Korea Institute of Information and Communication Engineering
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• v.21 no.6
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• pp.1231-1236
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• 2017

In this study, we developed a system that can change position to improve obstructive sleep apnea. Blocking of the breathing airway caused by obstruction of the apnea, lateral position is provided by the airway to improve the apnea. We used a pressure sensor (FSR402) in the form of an array to determine the position of patient. The air cylinder was controlled to raise and lower the bed. As a result of calculating the pressure difference between the supine position and the lateral position, it was $0.41{\pm}0.30$ and $1.09{\pm}0.73$. In other words, when the patient is lateral position, the difference between the sensor values on the right and left side is large. Therefore, it is confirmed that the system can maintain airway to breath for improvement of obstructive sleep.

• Journal of the Korea Institute of Military Science and Technology
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• v.1 no.1
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• pp.166-188
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• 1998

본 논문에서는 쿼터니온 궤환 개념이 기존의 오일러각 궤환 개념에 비해 추력벡터제어(Thrust Vector Control) 방식을 사용하는 전술 유도탄 자세제어에 보다 효과적으로 적용될 수 있음을 보인다. 오일러각 궤환 방식을 택한 기존의 자세제어기에서 오일러각 궤환 부분을 쿼터니온 궤환으로 적절히 바꾸어 주게 되면 자세명령 크기 변화에 따른 시간응답 특성의 변화를 줄일 수 있으며, 쿼터니온 궤환 방식을 택할 경우, 우주비행체 자세제어 분야에서 활발히 연구되고 있는 고유축(Eigen Axis) 회전에 의한 자세변환을 수행할 수 있는 자세제어기 설계가 가능하다. 고유축 회전은 최단경로에 의한 자세변환 개념이므로, 이러한 능력을 갖춘 자세제어기는 신속한 자세변환이 필요한 전술 유도탄의 초기비행에 매우 효과적으로 이용될 수 있다. 더욱이, 제어법칙에 공력모멘트를 보상하는 항을 추가하게 되면 변화가 심한 공력 모멘트가 유도탄의 회전운동에 미치는 영향을 줄일 수 있어 고유축 회전성능을 보다 개선시킬 수 있다. 우선, 오일러각 궤환보다 쿼터니온 궤환이 유리한 점을 논하고, 쿼터니온 궤환에 근거한 자세제어기의 설계 개념과 제안된 제어기에 의해 구성되는 폐루우프에 대한 안정성 문제를 다룬 후, 시뮬레이션을 통해 그 타당성을 검증한다.

• Proceedings of the Korean Information Science Society Conference
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• 2001.10b
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• pp.520-522
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• 2001

본 논문에서는 동작 표본을 이용하여 내재하는 동작 특성을 추정하고, 이를 동작 변환에 적용하는 새로운 동작 변환 알고리즘을 제안한다. 기존의 역 운동학에 기반한 동작 변환 알고리즘은 우선 앤드 이펙터 (end effector)의 궤적 차이를 줄이도록 한 후, 자세 공간에서 동작간의 거리를 최소화하는 방향으로 자세를 변환시켰다. 그러나 동작간의 거리에 대한 정의가 명확하지 않고, 이렇게 생성된 동작이 동작 주체가 취할 수 있는 자세라는 보장이 없기 때문에 실존 가능성이 낮은 부자연스러운 동작이 생성될 수 있다. 본 논문에서 제안하는 방법은 역 운동학 기반의 실존 가능성이 높은 자연스러운 동작 생성을 위해 동작 주체의 동작 표본을 고려한 확률분포를 이용한다. 제시된 알고리즘을 통한 동작 변환은 실존 가능성이 높은 자연스러운 동작을 생성할 수 있다.

• Journal of the Institute of Convergence Signal Processing
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• v.22 no.3
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• pp.128-133
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• 2021

Recently Recently, the incidence of spinal diseases due to poor posture among students and office workers is increasing, and various studies have been conducted to help maintain correct posture. In previous studies, a membrane sensor or a pressure sensor was placed on the seat cushion to see the weight bias, or a sensor that restrained the user was attached to measure the position change. In our previous study, we developed a sensor device which can be easily attached to the body with an adhesive gel sheet and that measures and outputs the user's posture and body position in real time, but it has a limitation in the accuracy of the sensor value. In this study, a study was conducted to improve the performance of the position conversion sensor device and quantitatively evaluate the accuracy of the angle conversion measurement value, and a high accuracy with 2.53% of error rate was confirmed. In future research, it is considered that additional research targeting actual users is needed by diversifying posture correction training contents with multimedia elements added.

• 재활복지
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• v.18 no.4
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• pp.221-235
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• 2014

Recently, the frequency of stroke disease is increased due to the rapid aging population, and is contributed to the major occurrence factors of the posteriori acquired disability. This study is about an postural change device for the control of supine posture which is an assisted equipment using in daily rehabilitation process for overcoming the disability by the aftereffects of the stoke disease. In this paper, the existing domestic and Japan postural appliances is examined and its comparison and categorization is performed according to its functions and purposes. Here, in order to control the supine posture state, the design method for advanced multi functional system is proposed, which is devised to have an unified mattress control operations of combining the bedsore prevention tube with the supine posture tilting tube. And also, in addition of an smart function, it is designed to enable to perform an RF functions such as the monitoring of the present device state, the alteration of the basic position and the control of alternative floating and supine posture. This system control hardware consists of three main parts : the sensor detection part, the motor driving /control part, and the system control part for bluetooth communication. In results, we confirmed that the system designed by this research is possible to make it practical as an advanced smart postural change device combined by IoT technology in the application field of the recent IT technology.

• Journal of the Institute of Convergence Signal Processing
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• v.24 no.1
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• pp.15-20
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• 2023

In general, maintaining an incorrect sitting posture for a long time is widely known to adversely affect the spine. Recently, several researchers have been interested in the causal relationship between incorrect sitting posture and spinal diseases, and have been studying methods to precisely measure changes in sitting or standing posture to prevent spinal diseases. In previous studies, we have developed a sensor device capable of measuring real-time posture change, applied a momentum calculation algorithm to improve the accuracy of real-time posture change measurement, and verified the accuracy of the postural change measurement sensor. In this study, we developed a posture measurement and analysis device that considers changes in the center of body pressure through the developed sitting pressure measurement, and it confirmed the sensor as an auxiliary tool to increase the accuracy of posture correction training with improving the user's visual feedback.

• Journal of the Institute of Convergence Signal Processing
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• v.21 no.2
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• pp.80-85
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• 2020

Recently the incidence of musculoskeletal disorders in students and office workers is increasing, and the necessity of maintaining correct posture and corrective training is required, but related research is insufficient. In the previous study, a membrane sensor or a pressure sensor was placed on the seat cushion to see the deviation of the body weight, or a sensor that restrained the user was attached to measure the position change. In this study, a sensor device for detecting a position change in consideration of wearing comfort was developed, and the measured angle was verified through an analysis app. A sensor device consisting of an IMU sensor is attached to the cervical spine and vertebra spine to measure the position transformation in the sitting position. The change value of the position measured by the two sensors was converted into an angle, and the angle value is displayed in real time through the analysis app. In this study, the possibility of measuring the real-time change value according to the change in position, the convenience of wearing, and the tendency of angle measurement were proved. Future research should proceed with more precise angle calculation and correction of motion noise.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.37 no.1
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• pp.28-35
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• 2009

This paper derives the equation of coordinated attitude formulation taking into account the orbital dynamics of a target vehicle and the attitude of a tracking satellite in geostationary orbit. The coordinated attitude is always to communicate with the ground station during the target tracking. Because the tracking satellite could perform high angle maneuver, MRP parameters having no singular point are used. Also for the sequential tracking of several target vehicles, the equation automatically making a coordinated attitude is suggested. Coordinated attitude flying and sequential tracking are confirmed through simulations. In short, this paper shows that a satellite could track a target vehicle and communicate with ground station simultaneously using the derived equation of coordinated attitude even though without a accuracy sensor.

• Proceedings of the Korean Society of Disaster Information Conference
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• 2023.11a
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• pp.349-350
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• 2023

본 논문에서는 FMCW(Frequency Modulated Continuous Wave) 레이더를 사용하여 재난 상황에서 누워 있는 사람의 다양한 각도의 자세를 통해 사람의 상태를 파악하거나 위치를 추정하고자하였다. 사람의 세 가지 누운 자세 데이터를 전처리하고 이미지로 변환한 데이터를 CNN(Convolutional Neural Network) 1D 모델로 학습시켜 누운 자세를 다양한 각도에서 구별할 수 있는지 분석하여 확인하고자하였으며, 분석 결과 CNN 1D 모델은 99.27%의 정확도를 보였다.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2004.04a
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• pp.135-140
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• 2004

In this paper, we study the posture control of an underwater vehicle with nonholonomic constraint. Generally, systems with nonholnomic constraints cannot be stabilized to an equilibrium points by smooth state feedback control. Therefore, we proposed a control strategy for posture control of the underwater vehicle using backstepping control. The proposed control scheme is applied to the posture control of an underwater vehicle and verified the effectiveness of control strategy by numerical simulation.