• Journal of the Korea Academia-Industrial cooperation Society
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• v.22 no.2
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• pp.507-513
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• 2021

This study examined the final stop position and posture of both vehicles, the damaged part of the vehicle, the road surface, the specifications of the vehicle, and the angle of impact, centering on the case of a collision in which no surface trace was found. As a result of the simulation, the impact velocity of an SM5 and Lexus was 131 km/h and 74 km/h, respectively, and the impact angle of the SM5 and Lexus was 0.91° and -161.07°, respectively. The cause of the accident was that the SM5 passed through the intersection exceeding the maximum speed limit of 61 km/h and entered the Lexus' left turn lane. Lexus collided during the evacuation to avoid the collision. The collision trajectory error rate of the simulation was approximately 1.4%. Of the subjective experience of accident investigators, the collision dynamics and vehicle engineering aspects and simulations were actively utilized to provide close-to-fact cause identification.

• Korean Journal of Applied Biomechanics
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• v.21 no.5
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• pp.551-560
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• 2011

The purpose of this study was to perform the kinematic analyses of the men's pole vault skills in IAAF World Championships Daegu 2011. Subjects were the 1st through 8th place finishers in the pole vault. The kinematic analyses were divided into four phases: two dimensional run up analysis, and three dimensional analyses for the remaining plant, swing up, and extension phases. Run-up variables consisted of run up distance, number of steps, average step length, the ratio of step length to his height, average velocity at the final 6~11 m, approach position. Three variables were analyzed during plant: pole angle, center of gravity (COG) velocity, and takeoff angle of COG. Swing up phase variables included: pole flexion angle, COG velocity (horizontal, vertical, resultant), COG trajectory and bar approach angle of COG. Compared to the 2009 World Championships in Berlin, the average vault height, run up velocity and approach position increased. However, horizontal velocity during the last two steps of the final approach decreased dramatically compared to speeds from 1990. These results reflect the change in both technique and improved physical fitness in pole vaulters. During extension, the peak height of COG averaged 0.3m higher then COG height when the pole was released. These specific results can help coaches and athletes modify training and improve performance.

• Korean Journal of Applied Biomechanics
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• v.21 no.5
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• pp.631-638
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• 2011

This study had two purposes. The first was to analyze the period of the final record set by the male shot-putters in the IAAF World Championships, Daegu 2011 from the point of view of kinematics. The other was to identify an efficient movement for shot putting based on the analysis. The research used the eight finalists of in the championship as subjects. We analyzed the seven most important kinematic factors in shot putting based on the type of technique: the execution time of the delivery phase, release velocity, release angle, release, center of mass (COM) velocity, and shot trajectories. The analytical results showed the following average figures for the record 12 meters: execution time of the delivery phase: (0.19 s), release height: (2.06 m), release angle: ($34.68^{\circ}$), release velocity: (13.25 m/s), angular velocity of shoulder: ($922.38^{\circ}/s$), and angular velocity of pelvis: ($479.50^{\circ}/s$). Further, the results showed that the highest COM velocity was 2.25 m/s and the shot trajectories were close to a straight line in the release phase.

• Journal of Institute of Control, Robotics and Systems
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• v.19 no.1
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• pp.1-9
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• 2013

This paper presents a new control algorithm for dynamic control of a unicycle robot. The unicycle robot motion consists of a pitch that is controlled by an in-wheel motor and a roll that is controlled by a reaction wheel pendulum. The unicycle robot doesn't have any actuator for a yaw axis control, which makes the derivation of the dynamics relatively simple. The Euler-Lagrange equation is applied to derive the dynamic equations of the unicycle robot to implement the dynamic speed control of the unicycle robot. To achieve the real time speed control of the unicycle robot, the sliding mode control and LQ regulator are utilized to guarantee the stability while maintaining the desired speed tracking performance. In the roll controller, the sigmoid-function based sliding mode controller has been adopted to minimize the chattering by the switching function. The LQR controller has been implemented for the pitch control to drive the unicycle robot to follow the desired velocity trajectory in real time using the state variables of pitch angle, angular velocity, angle and angular velocity of the wheel. The control performance of the two control systems form a single dynamic model has been demonstrated by the real experiments.

• Journal of Institute of Control, Robotics and Systems
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• v.3 no.1
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• pp.23-31
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• 1997

The sway control problem of pendulum motion of a container hanging on a Portainer Crane, which transports containers from a container ship to trucks, is considered in the paper. The equations of motion are obtained through the Lagrange mechanics and simplified for control purposes. Considering that the fast traveling of trolley and no residual swing motion of the container at the end of acceleration and deceleration are crucial for quick transportation, several velocity patterns of trolley movement including the time-optimal control are investigated. Incorporating the change of rope length, a reference swing trajectory is introduced in the control loop and the error signal between the reference sway angle and the measured sway angle is feedbacked. Proposed control strategy is shown to be robust to disturbances like winds and initial sway motion.

• Journal of the Korean Society of Industry Convergence
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• v.19 no.2
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• pp.81-87
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• 2016

This paper presents a new approach to control of stable motion of single wheel driving robot system of a pitch that is controlled by an in-wheel motor and a roll that is controlled by a reaction wheel. This robot doesn'thave any actuator for a yaw axis control, which makes the derivation of the dynamics relatively simple. The Lagrange equations was applied to derive the dynamic equations of the one wheel driving robot to implement the dynamic speed control of the mobile robot. To achieve the real time speed control of the unicycle robot, the sliding mode control and optical regulator are utilized to prove the reliability while maintaining the desired speed tracking performance. In the roll controller, the sigmoid-function based robust controller has been adopted to reduce the vibration by the situation function. The optimal controller has been implemented for the pitch control to drive the unicycle robot to follow the desired velocity trajectory in real time using the state variables of pitch angle, angular velocity, angle and angular velocity of the driving wheel. The control performance of the control systems from a single dynamic model has been illustrated by the real experiments.

• Korean Journal of Applied Biomechanics
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• v.17 no.4
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• pp.201-208
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• 2007

The purpose of this study is to compare 4 different body punch types(type 1: a punch using a shoulder, type 2: a punch using a waist, type 3: a punch using lower extremities, and type 4: a punch with elbows by your side at chest level) in horseback-riding stance and establish suitable teaching theory and method, which would be a useful reference to Taekwondo instructors on the spot(in Taekwondo dojangs all around Korea). Five exhibition players from Korean national Taekwondo exhibition team participated in this study. Each participant was asked to perform the four different types of punches and their kinematic and kinetic data were recorded with 7 vicon cameras(125Hz) and two force plates(AMTI, 1200Hz). We analyzed displacement, time, resultant center of body mass trajectory, velocity, trunk angular velocity, and ground reaction force(GRF) from each body segment in body punch and the result. I performed 1-way ANOVA(RM) for average values of each player after standardization and statistical significance was set as p<.05. was as the following ; First, they showed a tendency to take the body punch posture with the biggest motion at a shoulder and on descending order a waist and a knee. Second, a mean time for each body punch on ascending order 0.46sec. for type 2, 0.49sec for type 3, 0.50sec. for type 4, and 0.56sec. for type 1. Third, a mean resultant center of body mass trajectory for each body punch the longest 4.07cm for type 3 and the shortest 2.458cm for type 1. Fourth, a mean of maximal velocity of a fist strike was the fastest 5.99m/s for type 3, 5.93m/s for type 4, 5.67m/s for type 2, and 5.01m/s for type 1 on the descending order. Fifth, a mean of maximal trunk angular velocity of the fastest 495.6deg./sec. for type 4 and 337.7deg./sec. for type 1 on the descending order. Sixth, strongest value was type 3, 2 for anterior-posterior ground reaction force(left -54.89N, right 60.58N), type 4 for medial-lateral GRF(left 83.59N, right -80.12N), and type 3 for vertical GRF(left 341.79N, right 426.11N).

• 제어로봇시스템학회:학술대회논문집
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• 2004.08a
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• pp.1419-1423
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• 2004

In this paper, we propose an algorithm for planning an optimal path to capture a moving object by a mobile robot in real-time. The direction and rotational angular velocity of the moving object are estimated using the Kalman filter, a state estimator. It is demonstrated that the moving object is tracked by using a 2-DOF active camera mounted on the mobile robot and then captured by a mobile manipulator. The optimal path to capture the moving object is dependent on the initial conditions of the mobile robot, and the real-time planning of the robot trajectory is definitely required for the successful capturing of the moving object. Therefore the algorithm that determines the optimal path to capture a moving object depending on the initial conditions of the mobile robot and the conditions of a moving object is proposed in this paper. For real-time implementation, the optimal representative blocks have been utilized for the experiments to show the effectiveness of the proposed algorithm.

• 제어로봇시스템학회:학술대회논문집
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• 2003.10a
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• pp.186-190
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• 2003

In this paper, we propose an algorithm for planning an optimal path to capture a moving object by a mobile robot in real-time. The direction and rotational angular velocity of the moving object are estimated using the Kalman filter, a state estimator. It is demonstrated that the moving object is tracked by using a 2-DOF active camera mounted on the mobile robot and then captured by a mobile manipulator. The optimal path to capture the moving object is dependent on the initial conditions of the mobile robot, and the real-time planning of the robot trajectory is definitely required for the successful capturing of the moving object. Therefore the algorithm that determines the optimal path to capture a moving object depending on the initial conditions of the mobile robot and the conditions of a moving object is proposed in this paper. For real-time implementation, the optimal representative blocks have been utilized for the experiments to show the effectiveness of the proposed algorithm.

• Proceedings of the KIEE Conference
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• 1991.11a
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• pp.361-365
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• 1991

The problem being considered here is the determination of optimal guidance laws for a launch vehicle for scientific missions. The optimal guidance commands are determined in the sense that the least amount of fuel is used. A numerical solution was obtained for the case where the position and velocity state variables satisfy a specified constraint at the time of thrust cutoff. The method used here is based on the Pontryagin's maximum principle. This is the method of solving a problem in the calculus of variations. In particular, it applies to the problem considered here where the magnitude of the control is bounded. Simulations for the optimal guidance algorithm, during the 2nd and the 3rd-stage flight of the Japanese rocket M-3H-3, are carried out. The results show that the guided trajectory that satisfying the terminal constraints is optimal, and the guidance algorithm works well in the presence of some errors during the 1st-stage pre-programmed guidance phase.