• 한국정밀공학회지
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• 제33권7호
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• pp.579-586
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• 2016

This paper describes kinematic analysis of a 6-degrees-of-freedom (DOF) ultra-precision positioning stage based on a flexure hinge. The stage is designed for processes which require ultra-precision and high load capacities, e.g. wafer-level precision bonding/assembly. During the initial design process, inverse and forward kinematic analyses were performed to actuate the precision positioning stage and to calculate workspace. A two-step procedure was used for inverse kinematic analysis. The first step involved calculating the amount of actuation of the horizontal actuation units. The second step involved calculating the amount of actuation of the vertical actuation unit, given the the results of the first step, by including a lever hinge mechanism adopted for motion amplification. Forward kinematic analysis was performed by defining six distance relationships between hinge positions for in-plane and out-of-plane motion. Finally, the result of a circular path actuation test with respect to the x-y, y-z, and x-z planes is presented.

• Journal of Advanced Marine Engineering and Technology
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• 제34권2호
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• pp.318-324
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• 2010

본 논문에서는 새로운 구조의 6축 다관절 로봇 매니퓰레이터의 경량화와 토크성능을 높이기 위하여 어깨관절부위에 중력보상기를 설계하고 적용하였다. 또한, 매니퓰레이터의 기구학 및 역기구학 해석을 하였다. 자체 중량 30Kg의 경량이면서도 25Kg 고가반하중 인 우수한 성능을 구비할 수 있도록 매니퓰레이터의 링크 구조에 대한 FEM 해석을 수행하였다. FEM 해석을 통하여 로봇 매니퓰레이터의 굽힘이나 파단에 대한 안정성을 확인하였다.

• 대한물리의학회지
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• 제7권1호
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• pp.69-75
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• 2012

Purpose : The study was designed to investigate analysis of kinematics of lower extremity in healthy adults during walking with external loads on trunk. Methods : Fifteen healthy adults were recruited and The subjects provided written and informed consent prior to participation. They walked on a ten-meter walkway at a self-selected pace with loads of 0, 5, 10, and 15kg. They completed three trials in each condition and kinematic changes were measured. A three-dimensional motion analysis system was used to analyze lower extremity kinematic data. The data collected by each way of walking task and analyzed by One-way ANOVA. Results : There were significant differences in hip and knee joint on saggittal plane at initial contact and preswing, and significant differences in ankle joint on transverse plane at preswing. Conclusion : These findings revealed that increased external loads were changed joint angles and influenced postural strategies because of kinematic mechanism and future studies is recommended to find out prevention from damage of activities of daily living.

• 제어로봇시스템학회논문지
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• 제21권7호
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• pp.648-653
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• 2015

The kinematics with the instantaneous motion and statics of a manipulator has generally been proven algebraically. The algebraic solutions give very simple and straightforward results but the solutions do not have any meaning in physics or geometry. Therefore it is not easy to extend the algebraic results to design or control a robotic manipulator efficiently. Recently, geometrical approach to define the instantaneous motion or static relation of a manipulator is popularly researched and the results have very strong advantages to have a physical insight in the solution. In this paper, the instantaneous motion and static relation of a planar manipulator are described by geometrical approach, specifically by an axis screw and a line screw. The mass center of a triangle with weight and a perpendicular distance between the two screws are useful geometric measures for geometric analysis. This study provides a geometric interpretation of the kinematics and statics of a planar manipulator, and the method can be applied to design or control procedure from the geometric information in the equations.

• Nuclear Engineering and Technology
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• 제53권7호
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• pp.2251-2260
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• 2021

The motion control of the divertor maintenance system of the China Fusion Engineering Test Reactor (CFETR) was studied in this paper, in which CFETR Multi-Functional Maintenance Platform (MFMP) was simplified as a parallel robot for the convenience of theoretical analysis. In order to design the motion controller of parallel robot, the kinematics analysis of parallel robot was carried out. After that, the dynamic modeling of the hydraulic system was built. As the large variation of heavy payload on MFMP and highly nonlinearity of the system, A Fuzzy-PID controller was built for self-tuning PID controller parameters by using Fuzzy system to achieve better performance. In order to test the feasibility of the Fuzzy-PID controller, the simulation model of the system was built in Simulink. The results have showed that Fuzzy-PID controller can significantly reduce the angular error of the moving platform and provide the stable motion for transferring the divertor.

• 한국운동역학회지
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• 제13권3호
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• pp.99-116
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• 2003

The purpose of this study was to kinematics factors on during round-off at end of beam-salto backward stretched with step-out to cross on balance beam. Four elite female gymnastics players participated as subject of this study. The methods of this study was analyzed using three dimentional analysis. The results and conclusion of this paper is obtained as follows ; 1. The phase of time was the most short time in board touch down phase and board take-off phase. Also, it was shown a more long time in total time compared to previous study. 2. The horizontal displacement of each phase was shown the most high levels in balance beam landing. The vertical displacement was display a non-linearity increase in board take-of phase, and it was shown the most high levels in vertical displacement during landing of balance beam. 3. The horizontal velocity of each phase was shown the most high levels in board touch down, and it was display a gradually decreased levels because flight during board take-of. The resultant velocity of CG on each phase was shown the most high levels in board touch down and board take-off. 4. The angle of hip joint was shown the most high levels as performed a motion in extension state during board take-off, and the angle of knee joint was display a increased levels because of flight cause body extension in board take-off. Also the angle of ankle joint was shown a increasing levels during board take-off. Considering to this results, it is suggest that the change of kinematics factors in board touch down and board take-off is key role on the effective board control.

• 대한의용생체공학회:의공학회지
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• 제29권2호
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• pp.139-145
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• 2008

Many recent studies suggest that the posterior dynamic stabilization(PDS) can be a more physiologically-relevant alternative to the rigid fixation for the patients suffering from low back pain. However, its biomechanical effects or clinically proven efficacies still remain unknown. In this study, we evaluated kinematic behaviors of the lower lumbar spine with the PDS system and then compared to those of the rigid fixation system using finite element (FE) analysis. A validated FE model of intact lumbar spine(L2-L5) was developed. The implanted model was then constructed after modification from the intact to simulate two kinds of pedicle screw systems (PDS and the rigid fixation). Hybrid protocol was used to flex, extend, laterally bend and axially rotate the FE model. Results showed that the PDS systems are more flexible than rigid fixation systems, yet not flexible enough to preserve motion. PDS system allowed $16.2{\sim}42.2%$ more intersegmental rotation than the rigid fixation at the implanted level. One the other hand, at the adjacent level it allowed more range of motion ($2.0%{\sim}8.3%$) than the rigid fixation. The center of rotation of the PDS model remained closer to that of the intact spine. These results suggest that the PDS system could be able to prevent excessive motion at the adjacent levels and restore the spinal kinematics.

• 제어로봇시스템학회논문지
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• 제20권8호
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• pp.875-881
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• 2014

The redundancy resolution of the seven DOF (Degree of Freedom) upper limb exoskeleton is key to the synchronous motion between a robot and a human user. According to the seven DOF human arm model, positioning and orientating the wrist can be completed by multiple arm configurations that results in the non-unique solution to the inverse kinematics. This paper presents analysis on the kinematic and dynamic aspect of the human arm movement and its effect on the redundancy resolution of the seven DOF human arm model. The redundancy of the arm is expressed mathematically by defining the swivel angle. The final form of swivel angle can be represented as a linear combination of two different swivel angles achieved by optimizing two cost functions based on kinematic and dynamic criteria. The kinematic criterion is to maximize the projection of the longest principal axis of the manipulability ellipsoid of the human arm on the vector connecting the wrist and the virtual target on the head region. The dynamic criterion is to minimize the mechanical work done in the joint space for each of two consecutive points along the task space trajectory. The contribution of each criterion on the redundancy was verified by the post processing of experimental data collected with a motion capture system. Results indicate that the bimodal redundancy resolution approach improved the accuracy of the predicted swivel angle. Statistical testing of the dynamic constraint contribution shows that under moderate speeds and no load, the dynamic component of the human arm is not dominant, and it is enough to resolve the redundancy without dynamic constraint for the realtime application.

• 대한인간공학회지
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• 제35권5호
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• pp.319-341
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• 2016

Objective:This research analyzed the lower-limb motion in kinetic and kinematic way while walking on various terrains to develop Foot-Ground Contact Detection (FGCD) algorithm using the Inertial Measurement Unit (IMU). Background: To estimate the location of human in GPS-denied environments, it is well known that the lower-limb kinematics based on IMU sensors, and pressure insoles are very useful. IMU is mainly used to solve the lower-limb kinematics, and pressure insole are mainly used to detect the foot-ground contacts in stance phase. However, the use of multiple sensors are not desirable in most cases. Therefore, only IMU based FGCD can be an efficient method. Method: Orientation and acceleration of lower-limb of 10 participants were measured using IMU while walking on flat ground, ascending and descending slope and stairs. And the inertial information showing significant changes at the Heel strike (HS), Full contact (FC), Heel off (HO) and Toe off (TO) was analyzed. Results: The results confirm that pitch angle, rate of pitch angle of foot and shank, and acceleration in x, z directions of the foot are useful in detecting the four different contacts in five different walking terrain. Conclusion: IMU based FGCD Algorithm considering all walking terrain possible in daily life was successfully developed based on all IMU output signals showing significant changes at the four steps of stance phase. Application: The information of the contact between foot and ground can be used for solving lower-limb kinematics to estimating an individual's location and walking speed.

• 한국운동역학회지
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• 제21권1호
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• pp.107-114
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• 2011

Closed kinematic chain exercises such as squatting have been widely indicated for knee rehabilitation in patients with patellofemoral disorders such as osteoarthritis and patellofemoral pain. Patellofemoral disorders are thought to be associated with abnormal patellar kinematics. In addition, the Q-angle may be undervalued in patients with patellofemoral pain and a laterally displaced patella. The purpose of this study was to assess patellar kinematics and the Q-angle during double-leg semi-squat and wall-slide semi-squat exercises. In this study, 28 asymptomatic subjects(16 male, 12 female) were assessed. Patellar tilt, patellar spin, and Q-angle were recorded using a motion analysis system during double-leg semi-squat and wall-slide semi-squat exercises. The Q-angle and patellar tilt were significantly increased, whereas patellar spin was significantly decreased, at $45^{\circ}$ of knee flexion compared with $0^{\circ}$. No differences were observed for the Q-angle, patellar tilt, and patellar spin during double-leg semi-squat and wall-slide semi-squat exercises. However, a significant interaction was observed between squat type and knee angle for patellar spin. We found that the patella is laterally tilted during semi-squat exercises and that there was no difference in patellar tracking between knee flexion during double-leg semi-squat and wall-slide semi-squat exercises.