• Title/Summary/Keyword: Joint angular velocity

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Optimized Motion Planning Considering the Lifetime for Bimanual Robotic Assembly (양팔 로봇을 이용한 조립 작업에서 수명을 고려한 최적 운동 계획법)

  • Hwang, Myun Joong
    • Journal of Institute of Control, Robotics and Systems
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    • v.21 no.10
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    • pp.972-976
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    • 2015
  • The objective of this research is to verify the quantitative efficiency of a bimanual robotic task. Bimanual robots can realize dexterous and complicated motions using two cooperating arms. However, its motion planning and control method are not simple for implementing flexible tasks such as assembly. In this paper, the proposed motion planning method is used to find an optimal solution satisfying a designed cost function and constraints with regard to the kinematics and redundancy of the bimanual robot. The simulation results show that the lifetime of the manipulator can be changed by the proposed cost function consisting of angular velocity and angular acceleration of each joint in the same assembly task.

Kinetic analysis of the elbow joint in human motion (인체운동에 있어서 주관절의 운동학적 분석)

  • Noh, Tae-Hwan;Kim, Sik-Hyun;Kim, Jae-Hun
    • PNF and Movement
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    • v.5 no.1
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    • pp.49-56
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    • 2007
  • Objectives : We find that the reaction force on the elbow joint during elbow flexion, extension with and without an object in the hand can be calculated the equations of motion that the sum of the torque and the sum of the force acting on the elbow joint must be zero and (moment of inertia x angular acceleration) and (mass x acceleration). Methods : we have calculated the equations of motion (${\Sigma}F=0$, ${\Sigma}{\tau}=0$, ${\Sigma}F=ma$, ${\Sigma}{\tau}=Ia$) to investigate the reaction force on the elbow joint during elbow flexion, extension by means of the simplified free-body technique for coplanar forces. Results : we found that the reaction force on the elbow joint during elbow flexion, extention as constant acceleration motion is more than constant velocity, static motion. Also, we found that the relation between during flexion and during extension like this ; $J_{flexion}$ < $J_{extension}$.

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Comparison on the Kinematic Variables of Racket Movement According to Velocity in Tennis Serve (테니스 서브 속도에 따른 라켓 움직임의 운동학적 변인 비교)

  • Lee, Dong-Jin;Oh, Cheong-Hwan;Jeong, Ik-Su;Park, Chan-Ho;Lee, Gun-Hee
    • Korean Journal of Applied Biomechanics
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    • v.19 no.2
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    • pp.337-345
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    • 2009
  • The purpose of this study were to find out the differences in kinematic variables of racket movement by performing the tennis serve. Three top male tennis players participated in this study. Three synchronized high-speed cameras were used to record the service action of top players for Three dimensional video analysis. The results of this study showed that (1) the velocity of the tennis racket at impact is important to the generation of racket velocity to Y-axis. This result indicates that forward motion and upward movement of the racket; (2) with respect to racket angular velocity at impact, the fast angular momentum of X-axis is important to generate the velocity of the tennis ball. This result indicate upward movement of the racket with a strong flexor of wrist joint; (3) the velocity of the tennis ball was influenced by the change of angular linking the Z-axis to -X-axis. This result indicates that the high velocity of the tennis ball is obtained from having the racket unitedly moving to the direction of the bill's flight at the acceleration interval and acquiring the distance of acceleration with the racket head vertically to the ground at the back scratching.

Effects of Changes in Illumination Level and Slope on Fall-Related Biomechanical Risk Factors While Walking for Elderly Women (조도와 주로 변화가 노인 여성 보행 시 낙상 관련 운동역학적 위험요인에 미치는 영향)

  • Jeon, Hyun-Min;Park, Sang-Kyoon
    • Korean Journal of Applied Biomechanics
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    • v.25 no.4
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    • pp.413-421
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    • 2015
  • Objective : The purpose of this study was to investigate biomechanical changes of the lower limb including dynamic stability with changes in illumination (300Lx, 150Lx, and 5Lx) and slope (level and $15^{\circ}$ downhill) as risk factors for elderly falls. Method : Fifteen elderly females were selected for this study. Seven infrared cameras (Proreflex MCU 240: Qualisys, Sweden) and an instrumented treadmill (Bertec, USA) surrounded by illumination regulators and lights to change the levels of illumination were used to collect the data. A One-Way ANOVA with repeated measures using SPSS 12.0 was used to analyze statistical differences by the changes in illumination and slope. Statistical significance was set at ${\alpha}=.05$. Results : No differences in the joint movement of the lower limbs were found with changes in illumination (p>.05). The maximum plantar flexion movement of the ankle joints appeared to be greater at 5Lx compared to 300Lx during slope gait (p<.05). Additionally, maximum extension movement of the hip joints appeared to be greater at 5Lx and 150Lx compared to 300Lx during slope gait (p<.05). The maximum COM-COP angular velocity (direction to medial side of the body) of dynamic stability appeared to be smaller at 150Lx and 300Lx compared to 5Lx during level gait (p<.05). The minimum COM-COP angular velocity (direction to lateral side to the body) of dynamic stability appeared smaller at 150Lx compared to 5Lx during level gait (p<.05). Conclusion : In conclusion, elderly people use a stabilization strategy that reduces walk speed and dynamic stability as darkness increases. Therefore, the changes in illumination during gait induce the changes in gait mechanics which may increase the levels of biomechanical risk in elderly falls.

Design and Control of a Passive Compliant Joint for Human-friendly Service Robots

  • Yoon, Seong-Sik;Sungchul Kang;Kim, Seung-Jong;Kim, Munsang;Yim, Heung-Soon;Kim, Young-Hwan
    • 제어로봇시스템학회:학술대회논문집
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    • 2002.10a
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    • pp.119.2-119
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    • 2002
  • In this paper a passive compliant joint (PCJ) for human-friendly service robots is presented. The PCJ is composed of a magneto-rheological damper and a spring for elasticity. In the magneto-rheological damper, a braking force proportional to the electric current is generated. It works as a viscous damper by controlling the electric current according to the angular velocity of spring displacement. The compliance property and position control of the PCJ are verified through experiments and simulations to a single DOF simple arm with the PCJ.

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The Process of the Interjoint and Intersegmental Coordination of Side Kick Motion in Taekwondo (태권도 옆차기 동작의 인체관절과 분절사이의 협응 과정)

  • Yoon, Chang-Jin;Chae, Woen-Sik
    • Korean Journal of Applied Biomechanics
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    • v.18 no.4
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    • pp.179-189
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    • 2008
  • The purpose of this study was to investigate interjoint and intersegmental coordination of lower segments in skill process. For the investigation, we examined the difference of resultant linear velocity of segments and angle vs angle graph. Novice subjects were 9 male middle school students who have never been experienced a taekwondo. We analyzed kinematic variables of Side Kick motion through videographical analysis. The conclusions were as follows. 1. Examining the graph of novice subjects' maximal resultant linear velocity of the thigh, shank, and foot segment, as it gets closer to the end of the training, the maximal resultant linear velocity in each segment increases which can be assumed to be a result of the effective momentum transfer between adjacent segments. 2 This research showed a sequential transfer from trunk, to thigh, and then to shank as it gets closer to the end of learning at intersegment angular velocity, and it also showed pattern of throwlike motion and pushlike motion. 3. In three dimension of flexion-extension, adduction-abduction and internal-external rotation of the thigh and shank segment, the angle-angle diagram of knee joint and of hip joint showed that dynamic change was indicated at the beginning of learning but stable coordination pattern was indicated like skilled subject as novice subjects became skilled.

Effects of Preparatory Movements on Performance of Sideward Responsive Propulsion Movement (사전동작이 좌우 반응 추진운동의 수행력에 미치는 영향)

  • Kim, Yong-Woon;Yoon, Te-Jin;Seo, Jung-Suk
    • Korean Journal of Applied Biomechanics
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    • v.15 no.3
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    • pp.9-19
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    • 2005
  • The purpose of this study was to analyze the effects of three different types of preparatory movement(squat, countermovement and hopping) in sideward responsive propulsion movement. 7 healthy subjects performed left and right side movement task by external output signal. 3D kinematics were analyzed The results were followed First, performance time in the countermovement and hopping conditions was shorter(10-20%) than that in the squat condition. The hopping condition that is more related to pre-stretch showed excellent performance. Second, time difference between after turned on the external signal and until take off was the primary factor in performance results among movement conditions. The preparatory phase before the propulsive phase in the squat condition produced more time than that in other conditions. The hopping condition showed the most short time in both the preparatory and the propulsive phase, therefore it was advantage for performance result Third, significant difference was not found in take-off velocity among movement conditions although there was difference of the time required in the propulsive phase. The maximum acceleration in the propulsive phase was larger in order of the hopping. countermovement, and squat condition. The countermovement and hopping conditions showed high take-off velocity although the propulsive phase in those conditions was shorter than that in squat condition. The pre-stretch by preparatory countermovement was considered as the positive factor of producing power in concentric contraction. Fourth, the hopping condition produced large angular velocity of joints. In hopping condition, large amount of moment for rotation movement was revealed in relatively short time and it was considered to cause powerful joint movements. In conclusion, the hopping movement using countermovement is advantage of responsive propulsion movement. It is resulted from short duration until take off and large amount of joint moment and joint power in concentric contraction by pre-stretch.

A Study on the Development of the Gear Profile Design Program (기어 치형 설계 프로그램 개발에 관한 연구)

  • Jung, Sung-Pil;Park, Tae-Won
    • Journal of the Korean Society for Precision Engineering
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    • v.26 no.8
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    • pp.104-111
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    • 2009
  • In this paper, the gear design program is presented. The profile of gears is created using classical mathematic formulations. In each gear, a kinematic joint is applied and one can define the 20 contact condition between gear pairs. Initial and boundary conditions such as force, torque, velocity, acceleration, etc. can be set. Thus, it is possible to analyze dynamic characteristics of gear pairs such as reaction moment and the variation of angular velocity. In order to find the optimal profile of gear pairs, two optimization methods based on design of experiments are inserted in the program; One is the Taguchi method and the other is the response surface analysis method. To verify the program, the rack & pinion gear is created and analyzed. Simulation results show that the developed program is useful and result data is reliable.

A Kinematic Analysis of Glide Kip Motion on the Uneven Bars (이단 평행봉 차오르기 동작의 운동학적 분석)

  • Kim, Seung-Kwon;Kim, Seoung-Eun;Jang, Dae-Sun
    • Korean Journal of Applied Biomechanics
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    • v.23 no.4
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    • pp.307-318
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    • 2013
  • The purpose of this study was to analyze the kinematic variables of glide kip motion on the uneven bars through a two-dimensional cinematography. Three expert female gymnastics players were involved in the data gathering process. The followings were concluded according to the results. The arm, trunk and leg segments were fully extended throughout the kip movement. The whole body center of gravity showed the biggest changes during 66 to 87% of the kip motion. During the kip phase, the horizontal displacement of the leg was greater than the vertical displacement the leg. Glide kip motion should be done in orders of upward movement of leg, forward movement of leg, upward movement of trunk and forward movement of trunk segment. It was found that trunk segment and hip joint movements showed bigger changes than those of leg segment and shoulder joint in the glide kip motion. The largest angular velocity of hip joint was shown in the middle of the kip Phase. In conclusion, effective kip movement could be resulted when the trunk was displaced posterior-upward direction with fast hip joint extension after the leg segment was elevated upward and thrusted forward in advance.

Effect of Sports Taping on Impact Forces and Muscle Tuning during Drop Landing (드롭 착지 시 스포츠 테이핑이 하지의 충격력과 근육 조율에 미치는 영향)

  • Kang, Nyeon-Ju;Chae, Woen-Sik
    • Korean Journal of Applied Biomechanics
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    • v.20 no.2
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    • pp.175-182
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    • 2010
  • The purpose of this study was to evaluate the biomechanical effect of sports taping on the lower limb during drop landing. Twelve male university students who have no musculoskeletal disorder were recruited as the subjects. Principal strain, median frequency, vertical GRF, loading rate, angular velocity and resultant joint moment were determined for each trial. For each dependent variable, paired t-test was performed to test if significant difference existed between taped and untaped conditions(p<.05). The results showed that principal strain of the thigh and the shank in taping group were significantly less than those found in control group. These indicated that sports taping may prevent excessive mechanical strain caused by impact force during the deceleration phase. Flexion(-)-extension(+) and varus(-)-valgus(+) resultant joint moment of the knee joint in taping group were greater than corresponding value for control group. It seems that extensor muscle of the knee joint were not only supported by sports taping during knee flexion but also sports taping is effective for minimizing the possibility of injury.