159,118 research outputs found

    Flow Direction Prediction of Ball Movement for Humanoid Robot Soccer Goalkeeper

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    In Robocup, The most important sensor on humanoid robot soccer is a camera. The camera serves as the eyes of the robot as well as in humans. This camera is used by the robot to detect the ball. The task of Humanoid Robot Soccer as a Goalkeeper is to keep the goal and must be able to block a ball that came directly to the goal from many directions so the ball is not got into the goal. As already been known, the results of the camera image captured is always later than the pictures that has been taken, moreover if the shooting process is added with image processing such as adjusting contrast, brightness, etc. then the delay in image capture will be even greater. This causes late in reaction to the Humanoid Robot Soccer Goalkeeper when it’s blocking the ball that coming from any direction. Therefore we need a computer vision technique to estimate the direction of movement of the ball so there is no delay in reaction to the robot in blocking the ball. In this paper is discussed the flow direction prediction of the ball movement for Humanoid Robot Soccer Goalkeeper. The processing of ball movement prediction is obtained by comparing the previous ball data detection and the latest data detection to get the direction of the ball movement. This robot is a second generation of humanoid robot called EFuRIO soccer (Fußball EEPIS Robot IO)

    The effect of ball-handling on lower extremity mechanics in soccer

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    HRS Honors Research Thesis ScholarshipNearly 240,000 soccer injuries are estimated to have occurred in the United States in 2014 with a high number of them non-contact in nature and involving the lower extremities. These injuries result in time-loss from training or match play, potential psychological consequences, and financial burdens. Epidemiological research suggests that these non-contact injuries may occur more frequently while ball-handling compared to defending in soccer. However, no prior studies have investigated the biomechanical implications of controlling a soccer ball with the feet while running and cutting that may help explain this finding. The purpose of this study was to compare knee and ankle joint moments and angles implicated in non-contact soccer injury mechanisms demonstrated during run-to-cut maneuvers performed with and without dribbling a soccer ball. Our hypothesis was that the cutting maneuvers performed while dribbling a ball would have a detrimental effect on biomechanical parameters associated with non-contact ankle and knee injuries. Seventeen healthy male collegiate soccer players participated in the study. Subjects performed ball-handling and running maneuvers while running straight ahead and also at a 45° cutting angle. All data were collected using three-dimensional motion capture with force plates embedded in the floor. Ball-handling had a significant effect on peak ankle internal rotation angle (p=0.010) and knee abduction angle (p=0.024). Changes in other parameters of interest, including peak ankle inversion moment and peak knee abduction moment, did not reach significance (p>0.05). In conclusion, ball-handling in soccer can detrimentally alter lower extremity joint mechanics of dynamic movements. The results of this study support the need for coaches to consider the implications of an athlete’s sport-specific movements when creating training programs for teams and individuals.A three-year embargo was granted for this item.Academic Major: Biomedical Scienc

    Finite element modelling and experimental study of oblique soccer ball bounce

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    In this study, we develop a finite element model to examine the oblique soccer ball bounce. A careful simulation of the interaction between the ball membrane and air pressure in the ball makes the model more realistic than analytical models, and helps us to conduct an accurate study on the effect of different parameters on a bouncing ball. This finite element model includes a surface-based fluid cavity to model the mechanical response between the ball carcass and the internal air of the ball. An experimental set-up was devised to study the bounce of the ball in game-relevant impact conditions. Ball speed, angle, and spin were measured before and after the bounce, as well as ball deformation and the forces during the impact. The finite element model has been validated with three different sets of data, and the results demonstrate that the finite element model reported here is a valuable tool for the study of ball bounce. After validation of the model, the effect of the friction coefficient on soccer ball bounce was studied numerically. Simulation results show that increasing the friction coefficient may result in reversal of the horizontal impact force

    Design and Construction of an Omni-Directional Soccer Ball Thrower

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    Introduction We are ODST the Omni-Directional Soccer Ball Thrower team which designed the soccer ball launching machine. Working in direct correlation with the project sponsor John Meade from Athlonic Sports this is the report outlining the soccer ball thrower. John from Athlonic Sports came up with the overall project and initial project vision. There are soccer ball launching machines on the market but lacking mobility, not amiable and are heavy. The design needed to be mobile, amiable, lightweight, and have a soccer ball capacity incorporated into the machine. This will allow coaches to repeatability place the soccer ball in certain location to improve the soccer player skills. Background Anyone who has played soccer can tell you how hard it is to consistently kick or throw a ball in the same manner when performing routine drills. Soccer ball launchers are the solution to the inconsistency. They help make practice both more potent and efficient, while also opening up the possibility for new drills and practice techniques. Currently, a variety of soccer ball launcher designs exist. But the portability both on and off the field has been a large challenge. The goal of this project was to create a design that allowed for ease of transportation to the field, as well as use on the field, increasing the marketability of its use

    KINEMATIC ANALYSIS OF LOWER LIMB IN FUTSAL BALL KICKING

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    The diameter of the futsal ball (200 mm) is smaller than that of the soccer ball by 20 mm, and the futsal ball also has lower resilience than the soccer ball. Because of these differences in the balls, it is thought that the kicking motions of futsal players are distinct from those of soccer players. No study has yet been conducted on the motion involved in kicking a futsal ball. The aim of this study was to clarify the difference between the motion involved in kicking the futsal ball with that involved in kicking the soccer ball

    Multi-camera analysis of soccer sequences

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    The automatic detection of meaningful phases in a soccer game depends on the accurate localization of players and the ball at each moment. However, the automatic analysis of soccer sequences is a challenging task due to the presence of fast moving multiple objects. For this purpose, we present a multi-camera analysis system that yields the position of the ball and players on a common ground plane. The detection in each camera is based on a code-book algorithm and different features are used to classify the detected blobs. The detection results of each camera are transformed using homography to a virtual top-view of the playing field. Within this virtual top-view we merge trajectory information of the different cameras allowing to refine the found positions. In this paper, we evaluate the system on a public SOCCER dataset and end with a discussion of possible improvements of the dataset

    The Effects on Soccer Dribbling Skills When Training With Two Different Sized Soccer Balls

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    The purpose of this study was to determine the effects, if any, on soccer dribbling skills in children, ages, 8-10, after practicing with different sized soccer balls during the season. The Kansas Youth Soccer Association (KYSA, 2008) and the United States Soccer Association (US Soccer, 2011) recommended that children use smaller sized soccer balls than regulation adult sized soccer balls. As indicated by the associations, the size three ball is recommended for children under 8 (U-8), the size four ball is recommended for children under 12 (U-12), and the size five ball is recommended for children older than 12. Twenty-four recreational soccer players from Kansas participated in the study. The participants were from two different teams. The children were randomly placed on the teams by the league officials, unless parents specifically requested a coach. The Mor-Christian General Soccer Ability Skill Test Battery was used to test soccer dribbling skills (Collins & Hodges, 2001 p. 208). Both teams were timed in a pretest for soccer dribbling skills. Team one, the experimental group, was tested using the size five ball, and team two, the control group, was tested using the size four ball. The pretest was followed by six weeks of practice using their assigned size balls. Practice consisted of 1 hour practices twice a week. At the end of the six weeks program, a posttest was administered to both teams. Data were collected and a t-test was used to analyze the data. The results of this study indicated that there was not a significant difference in dribbling skills between the children in the control group as compared to the children in the experimental group. While the size four ball revealed quicker time results, these numbers were not significant enough to rule out the effect of what would be expected by chance. Based on the finding of this study, the following conclusions were made: 1) ball size does not offset dribbling skills in young soccer players; 2) soccer players 8 to 10 years old should continue to play with the smaller size four ball; and 3) the weight and size of the larger ball may be too cumbersome for young players to control and develop dribbling skills

    Three-dimensional kinematic correlates of ball velocity during maximal instep soccer kicking in males

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    This is an Accepted Manuscript of an article published by Taylor & Francis Group in European Journal of Sport Science, on 23 April 2014, available online at: https://www.tandfonline.com/doi/abs/10.1080/17461391.2014.908956.Achieving a high ball velocity is important during soccer shooting, as it gives the goalkeeper less time to react, thus improving a player's chance of scoring. This study aimed to identify important technical aspects of kicking linked to the generation of ball velocity using regression analyses. Maximal instep kicks were obtained from 22 academy-level soccer players using a 10-camera motion capture system sampling at 500 Hz. Three-dimensional kinematics of the lower extremity segments were obtained. Regression analysis was used to identify the kinematic parameters associated with the development of ball velocity. A single biomechanical parameter; knee extension velocity of the kicking limb at ball contact Adjusted R(2) = 0.39, p ≤ 0.01 was obtained as a significant predictor of ball-velocity. This study suggests that sagittal plane knee extension velocity is the strongest contributor to ball velocity and potentially overall kicking performance. It is conceivable therefore that players may benefit from exposure to coaching and strength techniques geared towards the improvement of knee extension angular velocity as highlighted in this study.Peer reviewedFinal Accepted Versio

    Release angle for attaining maximum distance in the soccer throw-in

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    We investigated the release angle that maximises the distance attained in a long soccer throw-in. One male soccer player performed maximum-effort throws using release angles of between 10 and 60º, and the throws were analysed using two-dimensional videography. The player’s optimum release angle was calculated by substituting mathematical expressions for the measured relationships between release speed, release height and release angle into the equations for the flight of a spherical projectile. We found that the musculoskeletal structure of the player’s body had a strong influence on the optimum release angle. When using low release angles the player released the ball with a greater release speed and, because the range of a projectile is strongly dependent on the release speed, this bias toward low release angles reduced the optimum release angle to about 30°. Calculations showed that the distance of a throw may be increased by a few metres by launching the ball with a fast backspin, but the ball must be launched at a slightly lower release angle
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