• Korean Journal of Applied Biomechanics
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• v.14 no.3
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• pp.83-98
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• 2004

The purpose of this study was to investigate the test-retest of plantar pressures using the F-Scan system over speeds and plantar regions. 6 healthy female subjects in 20's were recruited for the study. Plantar pressure measurements during locomotor activities can provide information concerning foot function, particularly if the timing and magnitude of the loading profile can be related to the location of specific foot structures such as the metatarsal heads. The Tekscan F-Scan system consists of a flexible, 0.18mm thick sole-shape having 1260 pressure sensors, the sensor insole was trimmed to fit the subjects' right. left shoes - sneakers shoes & dress shoes. It was calibrated by the known weight of the test subject standing on one foot. The Tekscan measurements show the insole pressure distribution as a function of the time. This finding has important implications for the development of plantar pressure test protocols where the function of the forefoot is important. According to the result of analysis it is as follows 1) Center of force trajectory in women's dress shoes display direct movement, compare with center of force trajectory in Sneaker shoes displays a little bit curved slow pronation movement. Sneaker shoes in forefoot part display very quick supination movement, therefore, this shoes effects negative effectiveness for ankle's stability Considering center of force trajectory analyzing the more center of force close straight line, the more movement can be quick movement for locomotion. For foot pressure distribution, center of force trajectory in locomotion is better to curved trajectory with pronation movement. So sneaker shoes style is good shoes considering center of pressure distribution trajectory compare with women's dress shoes. 2) Women's dress shoes increased peak pressure in medial, this is effected by high hill's height. The more increased women's dress shoes's height, the more women's peak pressure will increase, pronation can increase compare with before. Supination movement increase, this focused pressure in lateral, also, supination increased more. If the supination movement increased, foot pressure focused in lateral, therefore, it is appeared force distribution in gait direction. This is bad movement in foot's stability. 3) Women's dress shoes in landing phase displayed a long time, this is when women's dress shoes wear, gait movement is unbalance, so, landing phase displayed a long time. For compensation in gait, swing phase quick movement. 4) Women's dress shoes displayed peak pressure distribution in lateral of rearfoot part, Sneakers shoes displayed peak pressure distribution in medial of forefoot part. Its results has good impact absorption compare with women's dress shoes. In forefoot part, sneakers shoes has good propulsive force compare with women's dress shoes.

• Journal of Biosystems Engineering
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• v.34 no.1
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• pp.57-62
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• 2009

Kinematic analysis of MTC (Muscle-Tendon Complex) units is a key indicator for diagnosis of patients with musculoskeletal disorders because the contracture or shortening of musculo-tendinous units is known to produce pathological gaits. Therefore, the principal objective of this study was to assess the length change in the triceps surae prior to and after wearing an AFO (Ankle-Foot Orthoses) in patients with musculoskeletal disorders during a gait. In this study, analyses were conducted using a Muscle Tendon Complex model coupled with the trajectory data from markers attached to anatomical landmarks. As a result, the maximum length change in the triceps surae during a gait was 4.87% when a barefoot walking group and a walking group with AFO were compared. In particular, the difference in length changes between both groups in Soleus MTC units was found to be statistically significant in all gait phases. Our results revealed that MTC length in the AFO walking group was clearly increased over that of the barefoot walking group. In the future, further studies will be required in order to more adequately assess musculoskeletal disorders using many cases studies with regard to agricultural working conditions because this study deals with the kinematic analysis of musculo-tendinous units in the case of clinical experiments.

• Journal of the Korean Society for Precision Engineering
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• v.31 no.10
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• pp.913-922
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• 2014

This paper describes design of a robotic above-knee prosthetic leg which is powered by electrical motors. As a special feature, the robotic prosthetic leg has enough D.O.F.s. For mimicking the human leg, the robotic prosthetic leg is composed of five joints. Three of them are called 'active joint' which is driven by electrical motors. They are placed at the knee-pitch-axis, the ankle-pitch-axis, and the an! kle-roll-axis. Every 'active joint' has enough torque capacity to overcome ground reaction forces for walking and is backlashless for accurate motion generation and high-performance balance control. Other two joints are called 'passive joint' which is activating by torsion spring. They are placed at the toe part and designed by Crank-rocker mechanism using kinematic design approach. In order to verify working performance of the robotic prosthetic leg, we designed a gait trajectory through motion capture technique and experimentally applied it to the robot.

• Proceedings of the KIEE Conference
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• 2001.11c
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• pp.87-90
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• 2001

This paper presents a design of new type biped robot and dynamic walking simulation for this system. The robot is distinguished from other one by which has a parallel mechanism type trunk and lead-screw type actuators to drive the joints of the trunk, knee and ankle. The basic consideration on the design is that it is able to accommodate itself to human's daily environments without any other modification of around and also to operate its upper limbs more smoothly with a spine functional trunk. It is designed according to a human with about 130 cm height and about 30 kg weight. And it also is able to dynamically walk on an even ground. It has constructed with total 14 DOFs which have two legs, a hip, and a trunk. The joints of each leg and trunk are adopted with a parallel structure which has good kinematic characteristics and take light weight. To test of the capacity of joint actuators and to analysis of the dynamic properties of the biped robot, optimized trunk trajectory is determined by means of an approximated FFT method based on ZMP criteria, and dynamic simulation is performed using DADS with a 1.1 time/step velocity on the even ground during four steps.

• Journal of the Korean Society for Precision Engineering
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• v.19 no.7
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• pp.43-50
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• 2002

This paper presents the new gait implementation of a biped robot with smooth walking using 3-dimensional continuous trunk motion and kick action of ankle joints. Trajectory generation ova trunk is performed not on a unit gait but on a whole walking interval. In applying kick action such as heel-touch or toe-off, varying coordinate system was employed for the simplification of the kinematic analysis. Desired ZMP (zero moment point) is also changed to implement the efficient kick action. As a result, balancing motion of the proposed gait was much more decreased than that of conventional one. Moreover, robot\\`s walking behavior is very smooth, natural and similar to the pace of a human. The walking experiment system is composed of eight AC servo motors and a DSP controller. The walking simulation and the experimental results are shown using the proposed new walking algorithm.

• Journal of the Korean Society for Precision Engineering
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• v.26 no.4
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• pp.72-81
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• 2009

The purpose of this paper is to accomplish the stable humanoid robot walking on the soft terrains. The goal of the humanoid robot development is to make the robotic system perform some tasks in human living environment. However, human dwelling environments are very different from those of laboratories, where varied experiments are performed by the robot. In many cases, the ground is soft or elastic unlike the floor of a laboratory. When a robot walks on the soft ground, the sole of robot contacts the uneven ground. This results in unstable walking or walking may be impossible according to the degree of softness. Therefore, the algorithm that facilitates stable walking on the soft ground surface is required. In this paper, we suggest an algorithm that controls the ankle to help the robot walk stably on the soft ground using the humanoid robot (ISHURO-II) as a real model. A humanoid robot walking on the soft ground was simulated to verify that the proposed algorithm results in stable walking.

• Journal of the Ergonomics Society of Korea
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• v.32 no.3
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• pp.245-252
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• 2013

Objective: This paper analyzes the changes on stride parameters, joint angles, and trajectories of the body parts due to high heels during walking and explains the causal relationship between the changes and high heels. Background: This study aims to indicate the comprehensive gait changes by high heels on the whole body for women wearing high heels and researchers interested in high-heeled walking. Method: The experiment was designed in which two different shoe heel heights were used for walking (1cm, 9.8cm), and twelve women participated in the test. In the experiment, 35 points on the body were tracked to extract the stride parameters, joint angles, and trajectories of the body parts. Results: Double support time increased, but stride length decreased in high-heeled walking. The knee inflexed more at stance phase and the spine rotation became more severe. The trajectories of the pelvis, the trunk and the head presented outstanding fluctuations in the vertical direction. Conclusion: The double support time and the spine rotation were changed to compensate instability by high heels. Reduced range of motion of the ankle joint influenced on the stride length, the knee flexion, and fluctuations of the body parts. Application: This study can provide an insight of the gait changes by high heels through the entire body.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.23 no.3
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• pp.247-253
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• 2019

In this paper, we present a new method for real-time tracking of human walking around a laser sensor system. The method converts range data with $r-{\theta}$ coordinates to a 2D image with x-y coordinates. Then human tracking is performed using human's features, i.e. appearances of human walking pattern, and the input range data. The laser sensor based human tracking method has the advantage of simplicity over conventional methods which extract human face in the vision data. In our method, the problem of estimating 2D positions and orientations of two walking human's ankle level is formulated based on a moving trajectory algorithm. In addition, the proposed tracking system employs a HMM to robustly track human in case of occlusions. Experimental results using a real system demonstrate usefulness of the proposed method.

• Journal of Biomedical Engineering Research
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• v.43 no.2
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• pp.81-93
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• 2022

Proprioception training has been considered a secondary method to facilitate postural control ability. This study investigated the effects of two different proprioception training methods - the proprioceptive neuromuscular facilitation (PNF) and visual feedback-based joint position and force reproduction (VF) - on postural control advancements. Sixteen healthy people volunteered for this study, and they randomly grouped two. Each group participated in the PNF and VF training for three weeks. We evaluated each subject's proprioception levels and balance ability before and after the training. We used a clinometer and electromyogram (EMG) for VF training. The joint position reproduction test was also used to evaluate the position and force aspects of the proprioception level. We analyzed the trajectory of the center of pressure (COP) while subjects were standing on the firm floor and balance board with one leg using a pressure mat. The improvement of the position aspect of the proprioception level of the VF group (4.93±4.74°) was larger than that of the PNF group (-0.43±2.08°) significantly (p=0.012). The improvement of the anterior-posterior COP velocity of the PNF group (0.01±0.01 cm/s) was larger than that of VF group(0.002±0.01 cm/s) significantly (p=0.046). Changes of position error in the PNF group (rho=0.762, p=0.028) and tibialis anterior force reproduction error in the VF group showed a significantly strong relationship with balance ability variables. These results showed that different PNF and VF have different effects on improving two aspects of proprioception and their relationship with the balance ability. Therefore, these results might be useful for selecting proprioception or balance rehabilitation considering the clinical and patients' situation.