• Journal of the Korean Data and Information Science Society
• /
• v.20 no.3
• /
• pp.527-539
• /
• 2009

The purpose of this study was to evaluate the influence of ankle joint mobilization on equilibrium ability of supinated foot. Both Joint mobilization group(n=20) and control group(n=20) were measured an equilibrium ability by Balance performance monitor at pre-test, post-test in 2 weeks, post-test in 4 weeks and follow-up test in 2 weeks. The sway area, sway path length and sway maximum velocity of the joint mobilization group were significantly reduced among the experimental period (p<.05). The reduction of sway area, sway path length and sway maximum velocity were significantly different between the joint mobilization group and the control group at in 2 weeks, 4 weeks and follow-up test(p<.05). In conclusion, we were found that ankle joint mobilization could reduce sway area, sway path length and sway max velocity and improve a balance for the individuals with supinated foot.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2002.05a
• /
• pp.428-431
• /
• 2002

Yard cranes are very useful equipments for handling of heavy containers. But rope-driven yard cranes must have a little of sway and skew motion because ropes are passive mechanical device. So many researches have been concentrated on anti-sway algorithm controlling trolley speed. But control algorithm of trolley speed is not practical in windy weather. In this paper, we are going to propose a new structure for anti-sway. This structure uses aux. ropes. The control strategy with auxiliary rope is very useful to sway control of yard crane because rope length is shorter than quay-side container cranes. In this paper, we derive equations of motion of trolley system which have anti-sway controller to use auxiliary rope. And main schemes are introduced and explained briefly.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 1997.10a
• /
• pp.446-449
• /
• 1997

Yard cranes are very useful equipments for handling of heavy containers. But rope-driven yard cranes must have a little of sway and skew motion because ropes arc passive mechanical device. So many researches have been concentrated on anti-sway algorithm controlling trolley speed. But control algorithm of trolley speed is not practical in windy weather. In this paper, we are going to propose a new structure for anti-sway. This structure uses aux. :opes. The control strategy with auxiliary rope is very useful to sway control of yard crane because rope length is shorter than quay-sidc container cranes. In this paper, we derive cquatlons of motion of trolley system which have anti-sway controller to use auxiliary rope. And we propose the control strategy and analyse the behavior of the proposed system.

• Journal of The Korean Society of Integrative Medicine
• /
• v.6 no.2
• /
• pp.45-57
• /
• 2018

Purpose : This study was conducted to evaluate the effects of an task oriented training program combined with action-observation on balance and gait ability of patients with chronic stroke. Method : The subjects of this study were 30 patients with hemiplegia who agreed to participate and were picked up. Participants were randomly divided into equal groups; namely, an experimental group that underwent task oriented training combined with action-observation for at least 30 minutes/day for 6 weeks and a control group that underwent general task-oriented training. Patients' balance was assessed using the Sway Length, Sway Area and Limit of Stability test. In addition, gait ability was assessed using the 10 Meter Walking Test to measure the taken to walk 10 meters. Gait time and speed taken to walk 10 meters were used to examine gait ability. Results : There were significant improvements in the subscales of the balance and gait ability test of those who participated in the action-observational training program, while the control group showed only significant changes in the evaluation items of the sway length in eyes opened condition and gait time. Conclusion : Therefore, Action-observational training program effectively improved the balance and gait ability in patients with stroke.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
• /
• 2000.04a
• /
• pp.64-71
• /
• 2000

Yard cranes are very useful equipments for handling of heavy containers. But rope-driven yard cranes must have a little of sway and skew motion because ropes are passive mechanical device. So many researches have been concentrated on anti-sway algorithm controlling trolley speed. These approaches require sway angle. But it is very difficult to know sway angle and its derivative. Therefore control algorithm of trolley speed is not practical in general. On the contrary, control strategy using auxiliary rope is very useful to sway control of yard crane because rope length is shorter than quay-side container cranes. In this paper, we derive equations of motion of trolley system which have anti-sway controller to use auxiliary rope. And we propose the control strategy and analyse the behavior of the proposed system.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
• /
• 2000.11a
• /
• pp.143-151
• /
• 2000

Yard cranes are very useful equipments for handling of heavy containers. But rope-driven yard cranes must have a little of sway and skew motion because ropes are passive mechanical device. So many researches have been concentrated on anti-sway algorithm controlling trolley speed. These approaches require sway angle. But it is very difficult to know sway angle and its derivative. Therefore control algorithm of trolley speed is not practical in general. On the contrary, control strategy using auxiliary rope is very useful to sway control of yard crane because rope length is shorter than quay-side container cranes. In this paper, we derive equations of motion of trolley system which have anti-sway controller to use auxiliary rope. And we propose the control strategy and analyse the behavior of the proposed system.

• International Journal of Control, Automation, and Systems
• /
• v.5 no.4
• /
• pp.379-387
• /
• 2007

In this paper, a nonlinear anti-sway controller for container cranes with load hoisting is investigated. The considered container crane involves a planar motion in conjunction with a hoisting motion. The control inputs are two (trolley and hoisting forces), whereas the variables to be controlled are three (trolley position, hoisting rope length, and sway angle). A novel feedback linearization control law provides a simultaneous trolley-position regulation, sway suppression, and load hoisting control. The performance of the closed loop system is shown to be satisfactory in the presence of disturbances at the payload and rope length variations. The advantage of the proposed control law lies in the full incorporation of the nonlinear dynamics by partial feedback linearization. The uniform asymptotic stability of the closed-loop system is assured irrespective of variations of the rope length. Simulation and experimental results are compared and discussed.

• Journal of the Korean Society of Physical Medicine
• /
• v.12 no.3
• /
• pp.67-71
• /
• 2017

PURPOSE: Muscle fatigue is a cause to change proprioception. The purpose of this study was to investigate the effects of calf muscle fatigue and visual control on postural balance during single-legged standing in healthy adults. METHODS: Nineteen healthy adults (male) were participated in this study (mean age: 24.36 years; mean height: 171.32 cm; mean weight: 64.58 kg). The postural balance (sway length, sway area, sway velocity of COG displacement) was measured by Balance Trainer System (BT4) in before and after calf muscle fatigue feeling in single legged stance. In this study, repetitive single-legged heel rise test was used to induce fatigue of the calf muscle. Paired t- test was used to compare the postural balance between before and after calf muscle fatigue. Data of subjects were analyzed using SPSS 22.0 (SPSS Inc., Chicago, IL, USA). Level of significance was set to .05. RESULTS: The sway length, sway area, sway velocity of COG (center of gravity) displacement after calf muscle fatigue feeling was significantly increased compared to before calf muscle fatigue feeling during single leg standing both eye open and close conditions (p<.05). CONCLUSION: This study suggested that calf muscle fatigue feeling has affected on postural balance when standing one leg both eye open and close conditions and postural control was disturbed by muscle fatigue and visual feedback in single leg standing.

• Journal of Korean Physical Therapy Science
• /
• v.29 no.3
• /
• pp.56-62
• /
• 2022

Background: The purpose of this study was to investigate the effects of ankle joint immobilization on postural balance during quiet standing. Design: Cross-sectional study Methods: Twenty-seven healthy subject participated in this study. The subjects performed to stand quietly for 30s in eyes open on the platform with three different conditions. The sway length, sway area and sway velocity of center of gravity (COG) displacement and limit of stability (LOS) was measured using the balance platform. Repeated measured ANOVA was used to compare the postural balance parameters depending on three different ankle immobilized conditions. Results: Sway length, sway area and sway velocity of the COG displacement with bilateral ankle immobilized condition was significantly increased compared to those of the other two conditions(p<0.05). All directions of LOS with bilateral ankle immobilized condition were significantly decreased compared to those of the other two conditions. Conclusion: These findings suggest that ankle joint immobilization could be one of the factors that interfere the maintaining of the postural balance in quiet standing.

• Journal of Institute of Control, Robotics and Systems
• /
• v.21 no.2
• /
• pp.145-149
• /
• 2015

This paper introduces a sway suppression control for container cranes with unknown payloads and sway rates. With no priori knowledge concerning the magnitude of payload mass and sway rate, the proposed control maintains superior sway suppressing and trolley positioning against external disturbances. The proposed scheme combines a second order sliding mode control and an adaptive control to cope with unknown payloads. A second order sliding mode control without feedback of the sway rate is first designed, which is based on a class of feedback linearization methods for stabilization of the under-actuated sway dynamics of the container. Under applicable restrictions of the magnitude of payload inertia and sway rate, a linear regression model is obtained, and an adaptive control with a payload estimator is then designed, which is based on Lyapunov stability methods for the fast attenuation of trolley oscillations in the vicinity of the target position. The asymptotic stability of the overall closed-loop system is assured irrespective of variations of rope length. Simulation are shown in the existence of initial sway and external wind disturbances.