• Title/Summary/Keyword: Force Distribution

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Mechanical Analysis of golf driving stroke motion (골프드라이빙 스트로크시 역학적 분석)

  • Park, Kwang-Dong
    • Korean Journal of Applied Biomechanics
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    • v.12 no.1
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    • pp.205-219
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    • 2002
  • This research seeks to identify the plantar pressure distribution graph and change in force in connection with effective golf drive strokes and thus to help ordinary golfers have appropriate understanding on the moving of the center of weight and learn desirable drive swing movements. To this end, we conducted surveys on five excellent golfers to analyze the plantar pressure applied when performing golf drive strokes, and suggested dynamic variables quantitatively. 1) Our research presents the desire movements as follows. For the time change in connection with the whole movement, as a golfer raises the club head horizontally low above ground from the address to the top swing, he makes a semicircle using the left elbow joint and shaft and slowly turns his body, thus lengthening the time. And, as the golfer twists the right waist from the middle swing to the impact with the head taking address movement, and does a quick movement, thus shortening the time. 2) For the change in pressure distribution by phase, to strike a strong shot with his weight imposed from the middle swing to the impact, a golfer uses centrifugal force, fixes his left foot, and makes impact. This showed greater pressure distribution on the left sole than on the right sole. 3) For the force distribution graph by phase, the force in the sole from the address to halfway swing movements is distributed to the left foot with 46% and to the right foot with 54%. And, with the starting of down swing, as the weight shifts to the left foot, the force is distributed to the left sole with 58%. Thus, during the impact and follow through movements, it is desirable for a golfer to allow his left foot to take the weight with the right foot balancing the body. 4) The maximum pressure distribution and average of the maximum force in connection with the whole movement changed as the left (foot) and right (foot) supported opposing force, and the maximum pressure distribution also showed much greater on the left sole.

External Post-tensioning Strengthening of Composite Girder Bridge Using Lateral Distribution of Post-tensioning Force (긴장력 횡분배를 이용한 강합성형교 외부 후 긴장 보강)

  • Park, Young Hoon;Park, Yong Gul
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.29 no.6A
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    • pp.587-596
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    • 2009
  • This study analyzes the lateral distribution behavior of external post-tensioning force and evaluates the possibility of strengthening the servicing composite girder bridge by adopting the external post-tensioning force to the parts of the bridge girder. From the results of experiments and analyses, it is founded that the composite girder bridge can be strengthened by applying the external post-tensioning force to the parts of the bridge girder. It is also proved that bracing improve the lateral distribution behavior of post-tensioning force. The lateral distribution behavior of post-tensioning force which influenced by stiffness ratio, girder spacing and span length is changed by the bridge type and the location of tensioned girder. From the results of analyses, set up an equation which can predict the lateral distribution behavior of external post-tensioning force and evaluate the rationality.

An Application of the Force Rllipsoid to the Ooptimal Load Distribution of Cooperating Robots (힘 타원을 이용한 다중 협력 작업 로봇의 최적 부하 분배에 관한 연구)

  • 서창원;최명환;조혜경;이범희;고명삼
    • 제어로봇시스템학회:학술대회논문집
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    • 1991.10a
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    • pp.162-167
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    • 1991
  • The manipulability ellipsoid and the force ellipsoid for a single robot are extended to the case of a multi-robot system. The force ellipsoid is applied to solve the optimal load distribution for the multi-robot system. Two cases are considered in solving the optimal load distribution. In one case, there are no constraints on the joint torques, and the analytic solution ;a given. In the other case, the torque constraints are given in terms of the maximum power consumption, and the algorithm for the solution is proposed.

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Development and Application of System for Pressure Distribution Measurement (압력분포 측정용 시스템 개발 및 응용)

  • 김용환;박성하
    • Transactions of the Korean Society of Automotive Engineers
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    • v.11 no.6
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    • pp.134-140
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    • 2003
  • The film sensor is used for measuring pressure distribution at planar area, especially at a small space or gap. The present paper deals with the development of film type sensors and system for pressure distribution measuring. The developed system is consist of (1)film sensor with 40/sup */40 array, (2)PCI interface card with maximum sampling rate of 100㎐, and (3)software for data processing and real-time display. The contact pressure test of wiper blade and front glass of vehicle was performed with wiper blade by 40cm. Generally spring force of wiper arm is designed at 0.7∼1kN. Test results of total force was 9.4N and 7.1N in each driver and passenger toward. The paper suggested possibility for base definition in wiper design. A windshield wiper blade experiment revealed that the system successfully measured the contact force distribution during static state, showing the usefulness of the developed system.

Optimal Force Distribution for Quadruped Walking Robots with a Failed Leg (고장 난 다리가 있는 사족 보행 로봇을 위한 최적 힘 배분)

  • Yang, Jung-Min
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.58 no.3
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    • pp.614-620
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    • 2009
  • The force distribution in multi-legged robots is a constrained, optimization problem. The solution to the problem is the set points of the leg contact forces for a particular system task. In this paper, an efficient and general formulation of the force distribution problem is developed using linear programming. The considered walking robot is a quadruped robot with a locked-joint failure, i.e., a joint of the failed leg is locked at a known place. For overcoming the drawback of marginal stability in fault-tolerant gaits, we define safety margin on friction constraints as the objective function to be maximized. Dynamic features of locked-joint failure are represented by equality and inequality constraints of linear programming. Unlike the former study, our result can be applied to various forms of walking such as crab and turning gaits. Simulation results show the validity of the proposed scheme.

Force Distribution of a Six-Legged Walking Robot with High Constant Speed

  • Jung, Kwang-Suk;Baek, Yoon-Su
    • Journal of Mechanical Science and Technology
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    • v.14 no.2
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    • pp.131-140
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    • 2000
  • For a walking robot with high constant body speed, the dynamic effects of the legs on the transfer phase are dominant compared with other factors. This paper presents a new force distribution algorithm to maximize walkable terrain without slipping considering the dynamic effects of the legs on the transfer phase. Maximizing the walkable terrain means having the capability of walking on more slippery ground under the same constraint, namely constant body speed. A simple force distribution algorithm applied to the proposed walking model with a pantograph leg shows an improvement in the capability of preventing foot-slippage compared with one using a pseudo-inverse method.

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Electronic Control of Braking Force Distribution for Vehicles Using a Direct Adaptive Fuzzy Controller

  • Kim, Hunmo;Kim, Seungdae;Sung, Yoon-Gyeoung
    • Journal of Mechanical Science and Technology
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    • v.15 no.1
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    • pp.66-80
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    • 2001
  • In brake systems, a proportioning valve(P. V), which reduces the brake line pressure on each wheel cylinder for the anti-locking of rear wheels, is closely related to the safety of vehicles. However, it is impossible for current P. V. s to completely control brake line pressure because, mechanically, it is an open loop control system. In this paper we describe an electronic brake force distribution system using a direct adaptive fuzzy controller in order to completely control brake line pressure using a closed loop control system. The objective of the electronic brake force distribution system is to change the cut-in-pressure and the valve slop of the P. V in order to obtain better performance of the brake system than with mechanical systems.

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An Analysis of Wind Force Coefficient Distributions for Optimum Design of Single-Span Arched Greenhouse (아치형 단동온실의 최적설계를 위한 풍력계수분포도의 분석)

  • 이석건;이현우;권무남
    • Journal of Bio-Environment Control
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    • v.4 no.1
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    • pp.1-8
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    • 1995
  • One of the most destructive forces around greenhouses is wind. Wind loads can be obtained by multiplying velocity pressure by dimensionless wind force coefficient. Generally, wind force coefficients can be determined by wind tunnel experiments. The wind force coefficient distribution on a single - span arched greenhouse was estimated using experimental data and compared with reported values from various countries. The results obtained are as follows : 1. The coefficients obtained from this study agree with the values proposed by G. L. Nelson except about 0.5 of difference in the middle region of roof section. This discrepancy is mainly attributed to the dissimilarity of experimental conditions (or wind tunnel test such as Reynolds number, type of terrain, surface roughness of model, location of the lapping and measuring methods. 2. Considering that the wind force coefficients are varied along the height of a wall at wind direction perpendicular to wall, structural analysis using subdivided wind force coefficient distribution is more resonable for wall. 3. It is recommendable that wind force coefficient distribution on a roof should take more subdivision than the existing four equal divisions for more accurate structural design. 4. Structural design using wind forces close to real values is more advantageous in safety and expense.

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Prediction of Density Distribution in Sintered Metal Powder Compacts by Indentation Force Equation (압흔하중식에 의한 금속소결분말체내에서의 밀도분포 예측)

  • 박종진
    • Journal of Powder Materials
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    • v.4 no.3
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    • pp.188-195
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    • 1997
  • In most of sintered metal powder compacts, the sintered density distribution is controlled to be as high and uniform as possible to ensure the required mechanical properties. In general, the density distribution in the compacts is not uniform and not easy to measure. In the present study, a method for measuring the density distribution was developed, based on the indentation force equation by which the hardness and the relative density were related. The indentation force equation, expressed as a function of strength constant, workhardening coefficient and relative density, was obtained by finite element analysis of rigid-ball indentation on sintered powder metal compacts. The present method was verified by comparing the predicted density distribution in the sintered Fe-0.5%C-2%Cu compacts with that obtained by experiments, in which the density distribution was directly measured by machining the compacts from the outer surface progressively.

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A Novel Numerical Method for Considering Friction During Pre-stressing Construction of Cable-Supported Structures

  • Zhao, Zhongwei;Liang, Bing;Yan, Renzhang
    • International journal of steel structures
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    • v.18 no.5
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    • pp.1699-1709
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    • 2018
  • Suspen-dome structures are extensively used due to their superiority over traditional structures. The friction between cable and joints may severely influence the distribution of cable force, especially during the pre-stressing construction period. An accurate and efficient numerical method has not yet been developed that can be used for estimating the influence of friction on cable force distribution. Thus, this study proposes an efficient friction element to simulate friction between cable and joint. A flowchart for estimating the value of friction force is introduced. These novel numerical methods were adopted to estimate the influence of friction on cable force distribution. The accuracy and efficiency of these numerical methods were validated through numerical tests.