• PNF and Movement
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• 제20권3호
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• pp.431-441
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• 2022

Purpose: The purpose of this study was to compare the changes in the contact area, maximum pressure, maximum mean pressure, and maximum force of functional insoles and general insoles when walking. Methods: Foot pressure was measured by the ignition of functional insoles and general insoles on Company N shoes. The foot pressure was measured using a precision pressure distribution meter (Pedar - X mobile system, Novel, Germany). Each insole sensor contained 99 independent cells and was inserted between the foot and the shoe. A wireless Bluetooth-type program was used to measure the pressure detected by the measuring insoles. In order to eliminate adaptation and fatigue caused by wearing the guide during the experiment, sufficient rest was taken between each experiment, and the wearing order was randomly selected. Results: Functional insole significantly increased the forefoot and midfoot (medial, lateral) (p<0.05), while total foot, forefoot, and rearfoot peak pressure significantly decreased (p < 0.05) compared to the general insole. Conclusion: In the functional insole, a high contact area was measured inside, even in the middle of the foot, leading to a proper change in foot pressure. It was confirmed that the contact area was reduced and dispersion occurred well. In addition, it was found that the maximum pressure in the front and back of the entire foot was reduced, so the weight pressure dispersion in the functional insole was evenly distributed, and the maximum average pressure change was similar.

• 제어로봇시스템학회논문지
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• 제11권1호
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• pp.67-76
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• 2005

In this paper, An analysis on the intelligence system for a biped walking robot(BWR) was made and its results were applied to the BWR. Various sensors were applied to the developed BWR for autonomous and intelligent walk in unknown environments. To measure the distance between the object and BWR, ultrasonic sensor and infrared-rays sensor were used. To identity surrounding environments, vision system was used. Gyro sensor was used to control the posture of BWR. Also, piezoelectricity sensor was used to identity the pressure of foot landing on the surface. Sensors applied to the robot have measurement errors according to noises or walking environments. To improve the function of these sensors, influences of noise or sensing errors were minimized using a sensor fusion scheme. A gait test using the sensor fusion system was performed, and its results are presented.

• 한국정밀공학회지
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• 제22권3호
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• pp.170-178
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• 2005

The purpose of this study is to develop a gait-event detection system, which is necessary for the cycle-to-cycle FES control of locomotion. Proposed gait event detection system consists of a signal measurement part and gait event detection part. The signal measurement was composed of the sensors and the LabVIEW program for the data acquisition and synchronization of the sensor signals. We also used a video camera and a motion capture system to get the reference gait events. Machine learning technique with ANN (artificial neural network) was adopted for automatic detection of gait events. 2 cycles of reference gait events were used as the teacher signals for ANN training and the remnants ($2\sim5$ cycles) were used fur the evaluation of the performance in gait-event detection. 14 combinations of sensor signals were used in the training and evaluation of ANN to examine the relationship between the number of sensors and the gait-event detection performance. The best combinations with minimum errors of event-detection time were 1) goniometer, foot-switch and 2) goniometer, foot-switch, accelerometer x(anterior-posterior) component. It is expected that the result of this study will be useful in the design of cycle-to-cycle FES controller.

• 대한물리의학회지
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• 제7권2호
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• pp.223-230
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• 2012

Purpose : The purpose of this study was to analyze weight bearing of cane and affected foot at different speeds during walking. Methods : Thirteen subjects (6 males, 7 females) with stroke enrolled in the study. A foot sensor and an instrumented cane were integrated to analyze the vertical peak force on the affected foot and the cane. Results : The applied vertical peak force on the cane were $12.02{\pm}4.80%$ (slow speed), $7.97{\pm}3.95%$ (comfortable speed), and $6.86{\pm}3.30%$ (fast speed) body weight, respectively. The results indicated significantly lower vertical peak force on the affected foot in the low speed walking condition when compared to the fast walking (p<.05) and the comfortable walking (p<.05) conditions. The correlations between TUG and vertical peak force on the cane and affected foot were .71, and -.70 (p<.01). There was a higher correlation between the vertical peak force on the cane and affected foot were -.87(p<.01). Conclusion : In conclusion, slower walking speed applied greater vertical peak force on the cane. On the contray, slower walking speed applied less vertical peak force on the affected foot. Further studies, duration of force should be measured at different speeds during walking in lower and higher functioning hemiparetic subjects, as its use may mask underlying gait impairment.

• 한국운동역학회지
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• 제26권3호
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• pp.285-292
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• 2016

Objective: This study collected data on muscle fatigue and ground reaction force during walking to provide a basis for development of custom-fitted outdoor walking shoes. The study analyzed an upright body exercise program using spine stabilization technique to determine the effect on foot plantar pressure in archers, demonstrate the effectiveness of upright body exercise, and develop a new, effective, and efficient training program. Method: A 12-week upright body exercise program was evaluated for the effect on plantar pressure in archers. Ten prize-winning archers (3 men, 7 women) in B metropolitan city, each with ${\geq}10years$ of experience, were given an explanation of the content and purpose of the program, and provided informed consent. Upright body exercise was performed 3 times a week for 12 weeks. A resistive pressure sensor was used to measure foot plantar pressure distribution and analyze quantitative information on variation in postural stability and weight shifting in dynamic balance during shooting, as well as plantar pressure in static balance with the eyes open and closed. Results: There were no significant differences in foot plantar pressure before and after participation in the exercise program. There was no statistically significant difference in foot plantar pressure in static balance with the eyes open or closed, or in foot plantar pressure in dynamic balance during shooting. Conclusion: An upright body exercise program had positive effects on foot plantar pressure in static and dynamic balance in archers by reducing body sway and physical imbalance during shooting and with eyes closed. This program is expected to help archers improve their posture and psychological state, and thereby improve performance.

• 한국운동역학회지
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• 제28권1호
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• pp.9-18
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• 2018

Objective: This study aimed to analyze how the upright body type exercise program affected body balance and record of archers. This study aimed to prove the effectiveness of upright body type exercise, on this basis, in enhancing the performance of archery players. Method: A total of 14 archers (7 men and 7 women) in B Metropolitan City who had ${\geq}4years$ of career in archery and were given explanation of its contents and purpose before giving spontaneous consent to the experiment were enrolled in the study. The upright body type exercise program was implemented thrice a week for 12 weeks, with higher exercise intensity with time. A resistive pressure sensor, Gaitview AFA-50, was used to measure the foot plantar pressure distribution and analyze quantitative information concerning variation in posture stability and weight shift in dynamic balance of foot plantar pressure in shooting and static balance of plantar pressure with the eyes open and closed and the change in archery record accompanying the change in body balance. Results: As for the differences in foot plantar pressure between before and after participation in the upright body type exercise program, there was no significant difference in static balance of foot plantar pressure with the eyes open, and there was statistically significant difference at the ${\alpha}=.05$ significance level in static balance of foot plantar pressure with the eyes closed or in dynamic balance of foot plantar pressure in shooting. There was statistically significant difference at the ${\alpha}=.05$ significance level in archery record. Conclusion: The upright body type exercise program had positive effects on static and dynamic balance of foot plantar pressure by allowing archers to experience less body sway and physical imbalance in shooting with closed eyes and positive effects on archery record. Thus, the program is expected to help archers correct their posture and perform better.

• 센서학회지
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• 제26권5호
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• pp.353-359
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• 2017

This paper describes the design and manufacture of a ankle two-axis force sensor of a walking assist robot for hemiplegic leg patient. The walking assist robot for the hemiplegic leg patient can safely control the robot by detecting whether the foot wearing the walking assist robot is in contact with the obstacle or not. To do so, a two-axis force sensor should be attached to the robot's ankle. The sensor is used to measure the force of a patient's ankle lower part. The two-axis force sensor is composed of a Fx force sensor, a Fy force sensor and a pulley, and they detect the x and y direction forces, respectively. The two-axis force sensor was designed using by FEM(Finite Element Method), and manufactured using by strain-gages. The characteristics experiment of the two-axis force sensor was carried out respectively. The test results indicated that the interference error of the two-axis force sensor was less than 1.2%, the repeatability error and the non-linearity of the two-axis force sensor was less than 0.04% respectively. Therefore, the fabricated two-axis force sensor can be used to measure the force of ankle lower part in the walking assist robot.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2004년도 학술대회 논문집 정보 및 제어부문
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• pp.586-588
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• 2004

Although stable control algorithm has been implemented to the biped robot, the stability is not guaranteed because of encoder errors and/or rigid body elastics. Hence precise body pose estimation is required for more natural and long term walk. Specially pelvis sloping by gravity or uneven ground on landing place are most critical reason for undulated motion. In order to overcome these difficulties an estimation system for foot position and orientation using PSD sensors and Gyro sensors is proposed along with calibration algorithm and experimental verification.

• Journal of Positioning, Navigation, and Timing
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• 제11권1호
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• pp.35-44
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• 2022

In this paper, a dual foot (DF)-PDR system is proposed for the fusion of integration (IA)-based PDR systems independently applied on both shoes. The horizontal positions of the two shoes estimated from each PDR system are fused based on a particle filter. The proposed method bounds the position error even if the walking time increases without an additional sensor. The distribution of particles is a non-Gaussian distribution to express the lateral error due to systematic drift. Assuming that the shoe position is the pedestrian position, the multi-modal position distribution can be fused into one using the Gaussian sum. The fused pedestrian position is used as a measurement of each particle filter so that the position error is corrected. As a result, experimental results show that position of pedestrians can be effectively estimated by using only the inertial sensors attached to both shoes.

• 로봇학회논문지
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• 제5권1호
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• pp.48-54
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• 2010

Ankle-foot orthosis with a pneumatic rubber actuator, which is intended for the assistance and the enhancement of ankle muscular activities was developed. In this study, the effectiveness of the system was investigated during plantarflexion motion of ankle joint. To find a effectiveness of the system, the subjects performed maximal voluntary isokinetic plantarflexion contraction on a Biodex-dynamometer. Plantarfexion torque of the ankle joint is assisted by subject's soleus muscle that is generated when ankle joint do plantarflexion motion. We used the muscular stiffness signal of a soleus muscle for feedback control of ankle-foot orthosis as physiological signal. For measurement of this signal, we made the muscular stiffness force sensor. We compared a muscular stiffness force of a soleus muscle between with feedback control and without it and a maximal plantarflexion torque between not wearing a ankle-foot orthosis, without feedback control wearing it and with feedback control wearing it in each ten elderly adults. The experimental result showed that a muscular stiffness force of a soleus muscle with feedback control was reduced and plantarflexion torque of an ankle joint only wearing ankle-foot orthosis was reduced but a plantarflexion torque with feedback control was increased. The amount of a increasing with feedback control is more higher than the amount of a decreasing only wearing it. Therefore, we confirmed the effectiveness of the developed ankle-foot orthosis with feedback control.