• Title, Summary, Keyword: Stabilization

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Backstepping and Partial Asymptotic Stabilization: Applications to Partial Attitude Control

  • Jammazi, Chaker
    • International Journal of Control, Automation, and Systems
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    • v.6 no.6
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    • pp.859-872
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    • 2008
  • In this paper, the problem of partial asymptotic stabilization of nonlinear control cascaded systems with integrators is considered. Unfortunately, many controllable control systems present an anomaly, which is the non complete stabilization via continuous pure-state feedback. This is due to Brockett necessary condition. In order to cope with this difficulty we propose in this work the partial asymptotic stabilization. For a given motion of a dynamical system, say x(t,$x_0,t_0$)=(y(t,$y_0,t_0$),z(t,$z_0,t_0$)), the partial stabilization is the qualitative behavior of the y-component of the motion(i.e., the asymptotic stabilization of the motion with respect to y) and the z-component converges, relative to the initial vector x($t_0$)=$x_0$=($y_0,z_0$). In this work we present new results for the adding integrators for partial asymptotic stabilization. Two applications are given to illustrate our theoretical result. The first problem treated is the partial attitude control of the rigid spacecraft with two controls. The second problem treated is the partial orientation of the underactuated ship.

Digital Image Stabilization in the 2-axes Stabilization System using Zero-crossing of the Rotational Motion (2축 안정화 시스템에서 zero-crossing을 이용한 영상 안정화)

  • Kim, Dong-No;Kim, Gi-Hong;Jeong, Tae-Yeon;Gwon, Yeong-Do;Kim, Deok-Gyu
    • Proceedings of the KIEE Conference
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    • pp.396-399
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    • 2003
  • This paper proposes a simple digital image stabilization(DIS) algorithm for roll motion, which has not been compensated in the 2-axes mechanical stabilization system, using aero-crossing of the rotational motion vectors. The 2-axes stabilization system cannot stabilize rolled images, which causes the deteriorated performance of the object detection and recognition. In this paper, we propose the rotational motion stabilization algorithm which estimates and compensates global motion in terms of rotational center and rotational angle. Both the synthetic images with undesirable rotational disturbance and the real images from 2-axes stabilization system are used to evaluate the proposed algorithm. The results show that our proposed algorithm suppresses the undesirable rotational disturbance effectively.

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The Effects of the Meditation Music and Lumbar Stabilization Exercise on Concentration, Balance and Muscle Activity in Elderly

  • Lee, Sang-Bin
    • Journal of International Academy of Physical Therapy Research
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    • v.2 no.1
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    • pp.260-266
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    • 2011
  • The purpose of this study was to investigate the effects of meditation music with lumbar stabilization exercise on balance, concentration and muscle activation. Participants are divided into Group A and Group B. Group A listened to meditation music while doing 4 sets of lumbar stabilization exercise. Group B did not listen to meditation music while doing 4 sets of lumbar stabilization exercise. Surface EMG data was obtained rectus abdominis, external oblique, erector spinae, multifidus muscle during lumbar stabilization exercise. To examine the effect of before-after experiment for concentration and balance, paired t-test was adopted. Changes in EMG data of each muscles were analyzed by independence t-test. There were statistically significant increasing at concentration level and balance level in Group A. But significant difference was not shown in muscle activation. The clinical effect of the meditation music with lumbar stabilization exercise was investigated in this study with more excellent results in concentration and balance. In conclusion, these results suggest that meditation music and lumbar stabilization exercise may be useful in elderly people.

The Effect of Proprioceptive Neuromuscular Facilitation and Traditional Trunk Stabilization Training on the Rectus Abdominis Muscle Contraction (고유수용성신경근촉진 기법을 이용한 체간부 안정화 운동이 복직근 수축력에 미치는 효과)

  • Lee, Nam-Yong;Kim, Su-Hyon;Kim, Tae-Youl
    • Journal of the Korean Academy of Clinical Electrophysiology
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    • v.7 no.1
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    • pp.43-48
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    • 2009
  • Purpose : The purpose of this study was to study the effect of rectus abdominal muscle contraction by proprioceptive neuromuscular facilitation trunk stabilization training using extremity simultaneous pattern (PNF trunk stabilization training) and traditional trunk stabilization training methods. Methods : A group of 24 adults male and female, healthy, with no previous medical history nor disability in neuromuscular system and musculoskeletal system was chosen as subjects, and was divided into a control group, a PNF trunk stabilization training group and a traditional trunk stabilization training group. Experiments were performed on the last two groups, 3 times a week for 6 weeks, totaling 18 times. Using a dynamometer, muscle strength and endurance time on trunk flexion were measured before and after each experiment, and surface electromyography in left and right rectus abdominis were measured. Results : following results were obtained; 1. As for the change in the maximal voluntary isometric contraction (MVIC), all subjects in the trunk stabilization training group showed significant difference from those in the control group. 2. As for surface electromyography measurement and the changes in root mean square at the time of trunk flexion, in the left rectus abdominis, PNF trunk stabilization training group showed significant difference from the control group, while in the right rectus abdominis, traditional trunk stabilization training group showed significant difference. Conclusion : To sum up the results, both trunk stabilization training groups showed improvement in the MVIC of abdominal muscle, motor unit action potential activity, but the difference between two trunk stabilization training groups was not significant. Therefore, while trunk stabilization training significantly improved abdominal muscle contraction, but the difference attributable to training methods was found to be insignificant.

Kinematic and Image Stabilization of a Two-axis Surveillance System on Ship (선상 2축 감시장비의 기구 및 영상 안정화)

  • Lee, Kyung-Min;Cho, Jae-Hyun;Kim, Ho-Bum;Lyou, Joon
    • Journal of the Institute of Electronics Engineers of Korea SC
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    • v.49 no.4
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    • pp.55-60
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    • 2012
  • When operating a surveillance system in the maritime environment, its stabilization performance is degraded due to undesirable disturbance motions. For accurate target pointing of a 2-axes surveillance system on shipboard, the kinematic stabilization is first applied, which compensates a deviated motion via coordinate transformations of attitude information. Resultantly, the stabilization error is no longer reduced due to less accuracy of a MEMS sensor and kinematic constraint, leading to introduction of the image stabilization as a complementary function. And for real-time execution of the present dual stabilization scheme, a HILS (Hardware In the Loop Simulation) test bed including 6-dof motion simulator has been constructed, and through the obtained HILS data, it has been confirmed that the stabilization is successfully.

Physical Characteristics of Soft Clay Improved by PFA Stabilization Agent (제지회계 지반개량재로 처리된 연약점토의 물리적 특성)

  • 김광빈;이용안;김유성
    • Proceedings of the Korean Geotechical Society Conference
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    • pp.561-568
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    • 2002
  • PFA(Paper Fly Ash) are reclaimed mainly or used in cement industry field as mixture agent in terms of materials recycling. Recently, research for recycling PFA as embankment materials or soil stabilization agent are undergoing in geotechnical engineering field. In this study, physical characteristics of PFA stabilization agent-soil admixtures are examined in change of water content, void ratio, consistency, grain distribution, specific gravity and density. Futhermore, the physical characteristics are compared with unconfined strength as engineering characteristics. Test results showed that unconfined strength and density are increased with increasing of PFA stabilization agent mixed ratio. On the other hand, specific gravity, void ratio and water content are decreased with increasing of PFA stabilization agent mixed ratio. It would be concluded that natural high water content ratio weak soil could be highly improved engineering and physical characteristics with PFA stabilization agent

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Activation of Trunk Muscles during Stabilization Exercises in Four-point Kneeling (네발기기 자세에서 실시하는 안정화 운동에 따른 체간 근육의 활성도)

  • Lee, Hyun-Ok
    • The Journal of Korean Physical Therapy
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    • v.22 no.5
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    • pp.33-38
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    • 2010
  • Purpose: This study examined the activation of the rectus abdominis (RA), external abdominal oblique (EO), transversus abdominis, internal abdominal oblique (TrA/IO), and Multifidus (MF) muscles while stabilization exercise was performed in a four-point kneeling position. Methods: Experiments were conducted on 21 healthy male adults (mean age=25.29 years) who voluntarily agreed to participate in the study. Each subject was instructed regarding maximal voluntary contractions (MVC) and stabilization exercise in four-point kneeling. While MVC and stabilization exercise of individual muscles were being performed, activation of the muscles was measured using surface electromyography (EMG). Activation of the muscles while performing stabilization exercise in four-point kneeling was normalized to a percentages of the MVC. Results: Left RA, right TrA/IO, right and left MF muscles showed significant differences among the positions. Conclusion: Selecting an optimal position can aid subjects on physical conditions while performing stabilization exercises in the four-point kneeling position.

Stabilization of Mesophase Pitch for Carbon/Carbon Composites (탄소/탄소 복합재를 위한 메조페이스 핏치의 안정화)

  • 임연수
    • Journal of the Korean Ceramic Society
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    • v.34 no.8
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    • pp.817-824
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    • 1997
  • Stabilization is a key stage in the production of advanced carbon/carbon composites (ACC) from mesophase pitch, to render the mesophase infusible and the prevention of puffing during the subsequent carbonization. It is generally known that stabilization process as well as properties of mesophase pitch has a great deal of influence on the properties of the resultant ACC. Hence, it is possible to infer the properties of ACC by examing the stabilized mesophase pitch. In this study, extractions by solvents or acidified solvents extraction were carried out from the A-240 petroleum pitch. The extracted pitches were made into mesophase by heat treatments. Oxidative stabilization by air and non-oxidative stabilization by a chemical free radical initiator were performed. When a soluble polymer is fully stabilized, it should become insoluble in solvents. This phenomenon was used to estimated the degree of stabilization. The non-oxygen stabilized mesophase pitch powder was compared with the air stabilized mesophase pitch powder. FTIR provided additional information on the functional groups.

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Precision Stabilization Control of Servo-system by Using Friction Compensation (마찰보상을 통한 서어보제어계의 정밀 안정화 제어)

  • Kang, Min-Sig
    • Journal of the Korean Society for Precision Engineering
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    • v.16 no.3
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    • pp.109-115
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    • 1999
  • This paper presents a stabilization control designed to improve position stabilization performance of a position servo-system(turret) mounted on a manuvering platform(vehicle). In the consideration of the motion of the platform, a dynamic model of the stabilization system is derived and shows the viscous and stick-slip friction torques are the major source of stabilization errors. An extended generalized minimum variance control which consists of a feedforward disturbance compensation as well as a pole placement feedback control is suggested to reduce the stabilization errors caused from the friction disturbances. This modeling and control are applied to a small experimental set-up and the experimental results confirm the accuracy of the model and the effectiveness of the suggested control.

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Effects of Resistance and Resistance & Stabilization Exercises on the Strength of Lumbar and Lower Limbs of the Elderly

  • Choi, Seok Joo;Kim, Jong Woo;Hwang, Byeong Jun
    • Journal of International Academy of Physical Therapy Research
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    • v.4 no.2
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    • pp.611-617
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    • 2013
  • The purpose of this study is to identify the effective lumbar area exercise program to prevent falls of the elderly by dividing 14 female elders over 65 living in Daegu into two groups such as resistance exercise group and resistance & stabilization exercise group, and applying a 60 minute exercise program three times a week for 12 weeks. The followings are the results. First, both of resistance exercise and resistance & stabilization exercise brought improvement of lumbar strength and there was no significant difference between two groups. Second, there was no significant difference in lower limb strength in resistance exercise group but resistance & stabilization exercise group showed significant increase in lower limb flexor strength. To make a summary of the above results, it can be said that 12 weeks' resistance & stabilization exercise is effective to the lumbar strength and lower limb strength of the elderly. Accordingly, if combining resistance exercise and stabilization exercise appropriately, we can build a successful preventive program which even the elderly who cannot perform resistance exercise easily can follow.