• Proceedings of the KIEE Conference
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• 2005.10b
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• pp.255-257
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• 2005

This paper deals with the design and the realization of a small humanoid robot, which is called SERO_VI. The design concept and the mechanical structure including kinematics for the robot are presented. The humanoid robot consisted of 25 DOF with legs 12 DOF, arms 8 DOF, waists 3 DOF and heads 2 DOF for the purpose of vision system. The controller structure was also suggested such as modular joint actuators, DSP interface and their communication method. Simple experiment was done and its validness was investigated in order to verify the kinematic result.

• Proceedings of the IEEK Conference
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• 1999.11a
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• pp.548-551
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• 1999

We design a keyframe editor of arms and hands for 3D sign-language animation using inverse kinematics. In the previous study, we acquired only the joint angles of two arms after selecting arbitrarily the shapes of hands. In this paper, both joint angles of arms and hands are calculated by the same transformation matrix of the inverse kinematics. In the method, the design window of arm gestures can be converted into that of hand shapes by clicking a button. Experimental results show a possibility that the proposed method could be used for building up the sign-language communication dictionaries.

• Journal of the Korean Society for Precision Engineering
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• v.6 no.3
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• pp.32-45
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• 1989

The positioning accuracy of robots depends upon a forward kinematics which relates the joint variables to the orientation and position of the robot extremity in the absolute coordinate system. The relationship between two connective joint coordi- nates of a robot, which is the basis of the kinematics, is defined by 4 Denavit-Hartenberg parameters. But manufacturing errors in machining and assembly process of robots lead to disctrepancies between the design parameters and the physical structure. Thus, improving the positioning accuracy of robots reguires the identification of the actual link parameters of each robot. In this study, the least-squares method is used to calibrate the link parameters and off-line parameter calibration software is developed. Computer simulation is done to study the dependence of the calibration performance upon the DOF of the robot and number of acquired data set used in the least-squares method. 3 DOF Robot/Controller and specially designed 3D coordinate measurer is made and experiment is carried out to verify the theoretical and computational analysis.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2002.10a
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• pp.1088-1092
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• 2002

The purpose of this investigation was to study the kinematics of joints between foot segments based on computer graphic-based model during the stance phase of walking. In the model, ail joints were assumed to act as monocentric, single degree of freedom hinge joints. The motion of foot was captured by a video collection system using four cameras. The model fitted in an individual subject was simulated with this motion data. The kinematic data of tarsometatarsal joints and metatarso-phalangeal joint were quantitatively similar to the previous data. Therefore, our method using the computer graphic-based model is considered useful.

• Korean Journal of Applied Biomechanics
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• v.28 no.4
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• pp.237-244
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• 2018

Objective: Flat-footed people struggle with excessive ankle joint motion during walking and running. This study aimed to investigate the effects of customized three-dimensional 3D-printed insoles on the kinematics of flat-footed people during daily activities (walking and running). Method: Fifteen subjects (height, $169.20{\pm}2.61cm$; age, $22.87{\pm}8.48years$; navicular bone height, $13.2{\pm}1.00mm$) diagnosed with flat feet in a physical examination participated in this study. Results: The customized 3D-printed insoles did not significantly affect 3D ankle joint angles under walking and running conditions. However, they shifted the trajectory of the center of pressure (COP) laterally during fast walking, which enhanced the load distribution on the foot during the stance phase. Conclusion: The customized 3D-printed insoles somewhat positively affected the pressure distribution of flat-footed people by changing the COP trajectory. Further research including comparisons with customized commercial insoles is needed.

• Journal of the Korean Institute of Intelligent Systems
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• v.17 no.7
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• pp.862-868
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• 2007

The planar motion of the index finger in general human hands is usually implemented by the actuation of three joints. This task requires a technique to determine the joint combination for each fingertip position which is well-known as the inverse kinematics problem in robotics. Especially, it is an essential work for grasping and manipulation tasks by robotic and humanoid fingers. In this paper, an intelligent neural learning scheme for solving such inverse kinematics is presented. Specifically, a multi-layered neural network is utilized for effective inverse kinematics, where a dynamic neural learning algorithm is employed for fast learning. Also, a bio-mimetic feature of general human fingers is incorporated to the learning scheme. The usefulness of the proposed approach is verified by simulations.

• Korean Journal of Applied Biomechanics
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• v.12 no.1
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• pp.155-171
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• 2002

The purpose of this study was to provide basic data for a form of gait by comparing and analyzing gait motions on different grades and speeds. In order to accomplish the purpose, 6 university students, whose ages between 20 - 25, were selected. They have gaited on 3Km/h, 4Km/h, 5Km/h of speed and 4 video cameras were used to film them. The speed of filming was 60 frame / seconds. The special variations of kinematics in gait were fixed with ankle joint angle, knee joint angle, hip joint angle, ankle angular velocity, knee angular velocity and hip angular velocity. In this study, the SPSS 10.0 for windows statistical package was used to operate on significant level of .05 for statistical management. From the result of this study, we have succeeded to obtain following conclusions; 1. As the speed increased, the value of ankle joint angle increased. Also the value of ankle joint angle was larger on decline than on incline. 2. As the speed increased, the value of knee joint angle was increased. 3. As the speed increased, the value of hip joint angle was decreased. 4. As the speed increased, the value of ankle angular velocity increased. And the value of ankle angular velocity became higher on decline than on incline. 5. The value of knee angular velocity showed higher on decline than on incline. 6. As the speed increased, the value of hip angular velocity was increased. Also the value of hip angular velocity became higher on incline than on decline.

• The Journal of Korean Physical Therapy
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• v.26 no.2
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• pp.74-81
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• 2014

Purpose: The purpose of this study is to compare kinematics and kinetics on the knee joint between stair gait with unstable shoes and barefoot in healthy adult women. Methods: Seventeen healthy adult women were recruited for this study. The subjects performed stair ascent and descent with unstable shoes and barefoot. The experiment was repeated three times for each stair gait with unstable shoes and barefoot. Measurement and analysis of the movements of the knee joint were performed using a three-dimensional analysis system. Results: Statistically significant differences in the knee muscle force of semimembranosus, biceps femoris-long head, biceps femoris-short head and sartorius, patellar ligament, medial gastrocnemius, and lateral gastrocnemius were observed between unstable shoes and barefoot gait during stair ascent. Statistically significant differences in the knee muscle force of sartorius, rectus femoris, medial gastrocnemius, and lateral gastrocnemius were observed between unstable shoes and barefoot gait during stair descent. Statistically significant differences in the knee flexor moment of semitendinosus, biceps femoris-long head, biceps femoris-short head, sartorius, rectus femoris, vastus intermedialis, medial gastrocnemius, and lateral gastrocnemius were observed between unstable shoes and barefoot gait during stair ascent. Conclusion: Therefore, wearing unstable shoes during stair gait in daily life is considered to influence knee joint kinematics and kinetics due to the unstable shoes, and thus suggest the possibility that reducing the risks of pain, and knee osteoarthritis, stabilizing the knee joint caused by changes in the loading of the knee joint.

• Korean Journal of Applied Biomechanics
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• v.22 no.4
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• pp.379-386
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• 2012

The aim of this study was to investigate and identify the differences in lower extremity energy dissipation strategies between drop-landing and countermovement-jump maneuvers. Fourteen recreational athletes(Age : $23.3{\pm}2.1years$, Height : $172.3{\pm}4.0cm$, Weight : $69.2{\pm}4.7kg$) were recruited and instructed to perform drop-landing from 45 cm height and countermovement-jump from 45 cm to 20 cm height. The landing phase was taken as the time between initial contact and peak knee flexion. A motion-capture system consisting of eight infra-red cameras was employed to collect kinematics data at a sampling rate of 200 Hz and a force-plate was used to collect GRF data at a sampling rate of 2000 Hz. Paired t-test was performed to determine the difference in kinematics and kinetics variables between each task. During the countermovement-jump task, all of lower extremity joint ROM and the hip joint eccentric moment were decreased and the ankle joint plantarflexion moment was increased than drop-landing task. In the eccentric work during countermovement-jump task, the ankle joint displayed greater while knee and hip joint showed lesser than drop-landing. Therefore, the knee joint acted as the key energy dissipater during drop-landing while the ankle joint contributed the most energy dissipation during countermovement-jump. Our findings collectively indicated that different energy dissipation strategies were adopted for drop-landing and countermovement-jump.

• PNF and Movement
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• v.6 no.3
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• pp.29-35
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• 2008

Purpose : To describes the important aspects of the foot and ankle movement and function used when git and balance strategy. Method : The foot and ankle was a very important roles in the lower limb movement and gait. This study summarizes the physiologic movement of knee to the PNF lower extremity patterns. Result : The ankle joint composed of the talocural joint, the subtalarl joint, transverse tarsal joint, talocalcaneonavicular joint. The onset of dorsiflexion muscle activity starts in pre swing gait patterns. First contract muscle is the extensor hallucis. Activity of tibialis anterior and extensor digitorum longus quickly follows in mid swing gait phase. During stance phase, the soleus and gastrocnemius muscle provided plantar flexor torque, which muscle reacts quickly to restrain ankle dorsiflexion, and contributes modulated control of the ankle motion in gait patterns. Conclusions : The understanding of ankle kinematics, could provide a good therapeutic approach for improving gait patterns in patients with various pathological condition.