• 대한전기학회:학술대회논문집
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• 대한전기학회 2001년도 하계학술대회 논문집 D
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• pp.2408-2410
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• 2001

This paper presents the control of an underactuated two-link robot called the Pendubot. Combining linearized state feedback control with Takagi-Sugeno(T-S) fuzzy controller wide-range stabilization of Pendulum is achieved. The local stabilization controler is designed by linearinzing the dynamic equations about the several desired set point and using LQR(Linear Quadratic Regulator) techniques. Takagi-Sugeno methodology is used to control the nonlinear models near different operation points. Fuzzy controller is obtained by the fuzzy blending of the local controllers. The paper includes a description of the algorithm as well as real time experimental results for the Pendubot.

• 대한전기학회논문지
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• 제34권6호
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• pp.213-219
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• 1985

Superconducting Magnetic Energy Storage (SMES) system can be used for power system stabilization by absorbing or discharging active and reactive power through thyristor-comtrolled converters. In this paper, we have proposed a control algorithm that the active and reactive powers of SMES are simultaneously controlled to increase power system dynamic stability. The proposed method was applied to one machine-infinite and three machines and three load model systems. And it has been shown that the proposed algorithm is more effective in power system stabilization than the conventional one that only the active power of SMES is controlled. Eigenvalue sensitivity analysis method is introduced to estimate the optimal location of SMES in the sense of the power system oscillation mode.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2001년도 ICCAS
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• pp.71.4-71
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• 2001

This paper presents swing up and stabilization control of an underactuated two-link robot called the Pendubot. This device is a two-link planar robot with an actuator at the shoulder, but no actuator at the elbow. The controller swings up first link from its open loop stable equilibrium point to the unstable equilibrium point and then, catches the unactuated second link to balance it there. Two control algorithms are used for this task. Proportional Derivative Control technique is used to design the swing up control. The linear model of Pendubot is obtained by linearizing the nonlinear dynamic equations about the desired equilibrium point and LQR technique is used to design a stabilization controller.

• 국제물리치료학회지
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• 제12권2호
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• pp.2314-2322
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• 2021

Background: Back pain is associated with a high risk of recurrence. Various physical therapy techniques for back pain have been studied, including reprogramming the central nervous system by integrating sensation and motion with sensory exercise training. Objectives: To aimed verify the effectiveness of sensorimotor training in improving postural stability and pain levels. Design: A randomized controlled trial. Methods: The study population was randomized into a sensory exercise training group and trunk stabilization training group and treated three times a week for 4 weeks. Each group took part in sensorimotor training for 15 minutes or lumbar stabilization exercise for 15 minutes. Results: After the intervention both groups showed Improvements in the variables. There was a significant difference in the dynamic postural stability, limit of stability, and modified visual analog scale scores in the sensorimotor training group compared to the lumbar stabilization exercise group (P<.05). Conclusion: Sensorimotor training appears to be an effective physical therapy exercise program that can be applied in patients with low back pain to improve muscle control ability.

• 대한정형도수물리치료학회지
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• 제11권1호
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• pp.37-48
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• 2005

Objects: This study is designed to analysis improvement and maintaince of trunk stability targeting patients who need post operative rehabilitation exercise after undergoing opened microscopic laser discectomy(OMLD) due to HNP. Method: Between March 2004 and February 2005 a total sixty patients who underwent OMLD due to $L_4/L_5$, $L_5/S_1$ HNP and who agreed to the experiment were subject for this study. Experimental group consisted of 18 subjects, and they underwent 45 minutes dynamic lumbar stabilization exercise And control group consisted of 18 subjects who conducted conservative physical therapy based on the use of physical modality for 45 minutes except to exercise. Results: Experimental group that was lumbar extensor's isometric peak torque, weight distribution of both leg, trunk muscle balance and Oswestry LBP disability index increased during 12 weeks in a statistically significant manner compared to before exercise (p<.05). When re-test was tried, isometric peak torque (p>.05) and Oswestry LBP disability index(p<.05) maintained 12th week level or improved. Weight distribution rate of both leg and trunk muscle balance maintained the level of 8th week of exercise execution(p<.05). Control group that was lumbar extensor's isometric peak torque, weight distribution rate of both leg and trunk muscle balance aggravated during 12 weeks compared to pre-test(p>.05) But, Oswestry LBP disability index increased in a statistically significant level compared to pre-test(p<.05). When re-test was tried, isometric peak torque increased slightly compared to pre-test, but decreased when at least $60^{\circ}$ flexion angle(p>.05). Weight distribution rate of both leg and trunk muscle balance also aggravated compared to pre-test(p>.05), and Oswestry LBP disability index was similar to the 4th week of physical therapy execution(p>.05). Conclusion: Successive postoperative Especially, Application of dynamic lumbar stabilization exercise program is important than traditional lumbar strengthening exercise program in the maintaince of spinal stability.

• 한국항공우주학회지
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• 제37권4호
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• pp.399-405
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• 2009

위성 카메라를 위한 초점면부 영상 안정화 장치는 영상이 맺히는 초점면부의 운동외란을 제거함으로써 위성 카메라의 영상 품질을 향상 시킬 수 있는 효율적인 방법 중 하나이다. 본 연구의 목적은 초점면부 안정화 기법을 소개하고 초점면부 영상 안정화 장치 액츄에이터의 응답 및 추력에 대한 최적의 구동 조건을 결정하는 것이다. 이를 위해 다양한 구동 조건에 따른 영상화 안정화 장치의 마찰 구동형 압전 액츄에이터의 응답성과 추력을 실험적으로 조사하였다. 실험결과로부터 마그네슘 슬라이더에 대한 최적의 구동 주파수는 70 kHz, 듀티비는 27% 였다.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2003년도 제21회 추계학술대회 논문집
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• pp.73-77
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• 2003

액체 로켓엔진 개발과정에서 수행되는 여러 가지 시험 중 연소 안정성 평가 시험을 통해, KSR-III 로켓엔진의 연소 안정성을 평가하였다. 안정성 평가시험에서, 엔진이 외부 교란에 의한 압력 진통을 감쇠시켜 본래의 안정한 연소로 회복되는 경우, 그 엔진은 연소 안정화 능력을 가지고 있다고 판정할 수 있다. 로켓엔진은, 교란의 크기를 예측하기 어려운 외부 섭동에 노출될 수 있으므로, 엔진의 연소 안정화 가능 여부를 확인하는 것과 더불어 엔진이 갖고 있는 연소 안정화 능력을 정량화하여 파악하는 작업이 필요하다. 이를 위해 몇 가지 인자를 도입하였고, 이를 평가하는 방법을 검토하였다. 성공적으로 완료된 KSR-III 로켓개발과정에서 로켓엔진의 안정성 확보를 위해 5회의 안정성 평가 시험이 수행되었다. 이를 토대로, 앞서 언급한 안정화 능력의 정량화 방법을 KSR-III 엔진에 적용하여 그 엔진의 안정화 성능을 분석하였다.

• 한국소음진동공학회논문집
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• 제21권2호
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• pp.178-185
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• 2011

Optical image stabilization is a device to compensate the camera movement in the exposure time. The compensation is implemented by movable lens or image sensor that adjusts the optical path to the camera movement. Generally, the camera is moved by a handshake, thus the handshake is considered as an external disturbance. However, there are many other vibrations such as car and train vibration. In this paper, the optical image stabilization system in high frequency region is presented. Notch filter and lead compensator are designed and applied to improve the stability without changing the actuator. To verify the performance of the optical image stabilization system in high frequency region, the experiment equipment with moving object is established. It is confirmed that the opticalimage stabilization system does not diverge at the resonance frequency.

• 대한정형도수물리치료학회지
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• 제7권2호
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• pp.23-39
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• 2001

Dysfunction of the anterior and dorsal muscles of the trunk have been studied in relation to low back pain of many years. Many muscles of the trunk are capable of contributing to the stabilization and protection of the lumbar spine, recent evidence has suggested that transversus abdominis may be critically involved and has been the focus of rehabilitation. The delay in onset of contraction of trunk muscles associated with movement of the upper or lower limb in patients with low back pain indicates a significant deficit in the automatic motor command for control of disturbance to the spine. The function of transversus abdominis has been largely ignored in the evaluation of spinal stabilization and protection. The most essential stabilizing muscles for the lumbar column are the transversus abdominis and the multifidus. Sling exercise therapy(SET) concept consists of a system of diagnosis and treatment. The system of diagnosis involves testing the muscle's tolerance through progressive loading in open and close kinetic chains. The SET system contains elements such as relaxation, increasing the range of movement, traction, training the stabilizing musculature, sensorimotor exercises, training in open and close kinetic chains, dynamic training of the mobilizing musculature, cardiovasc+ular exercises, group exercise, personal exercise at home. Sensorimotor training is an essential element of the SET concept. The emphasis is on closed kinetic chain exercises on an unstable surface, thereby achieving optimum stimulation of the sensorimotor apparatus.

• 대한토목학회논문집
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• 제26권4D호
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• pp.671-678
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• 2006

본 연구에서는 2개의 질량을 갖는 1/4 차량모델을 이용하여 차량-궤도-교량간의 동적상호작용 현상을 표현하기 위해 비선형 헤르츠 접촉스프링(Nonlinear Hertzian Contact Spring)과 비선형 접촉감쇠장치(Nonlinear Contact Damper)를 도입하였다. 또한, 차량에 작용하는 하중은 차량의 중량외에 임의시간단계의 차륜재하위치인 레일답면(즉, 주행로상의 접촉면)에서의 변위가 제한조건식(Constraint Equation)으로 가해졌다. 이 변위제한조건식은 Penalty방법(Penalty Method)에 의해 구현되었으며, 해의 안정화(Stabilization)를 위한 기법과 제한조건오차보정반력(Reaction from Constraint Violation)을 도입하였다. 또한, 차량의 피칭운동을 표현하고, 다양한 차량/열차를 모형화하기 위해서 1/4 차량모델의 차체 및 대차프레임 간을 강체연결 및 핀이 있는 강체연결조건으로 모형화하였다. 시간적분방법으로는 Newmark계열의 시간적분법이 사용되었으며, 해의 정확성 확보를 위해 국지적 오차평가에 근거한 적응적시간간격기법(Adaptive Time-Stepping Scheme)을 도입하였다. 이러한 적응적시간간격기법을 도입하여 동적해석에서 시간간격의 크기를 자동적으로 결정함으로써 동적해석에서의 해의 정확성을 확보하고 시간적분에 소요되는 계산비용을 감소시킬 수 있을 것으로 기대된다.