• International Journal of Control, Automation, and Systems
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• v.1 no.2
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• pp.243-251
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• 2003

In this paper, a new model for mobile soccer robot, a type of linear system, is presented. A controller, consisting of two loops the one of which is the inner state feedback loop designed for stability and plant be well conditioned and the outer loop is a well-known PI controller designed for tracking the reference input, is suggested. Because the plant, the soccer robot, is parameter dependent, it requires the controller to be insensitive to the parameter variation. To achieve this objective, the pole-sensitivity as a pole-variation with respect to the parameter variation is defined and design algorithms for state-feedback controllers are suggested, consisting of two matrices one of which is for general pole-placement and other for parameter insensitive. This paper shows that the PI controller is equivalent to the state feedback and the cost function for reference tracking is equivalent to the LQ cost. By using these properties, we suggest a tuning procedure for the PI controller. We that the control algorithm in this paper, based on the linear system theory, is well work by simulation, and the LPD system modeling and control are more easy treatment for soccer robot.

• Korean Journal of Applied Biomechanics
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• v.19 no.4
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• pp.617-625
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• 2009

The primary purpose of this study was to compare the hamstring-to-quadriceps strength(H/Q) ratios in collegiate soccer players and normal age-matched healthy students, and the secondary purpose was to investigate the changes in the H/Q ratio according to the degree of knee flexion. Twenty-five subjects volunteered to participate in this study. The study group comprised 12 healthy male collegiate soccer players, and the control group, 13 healthy age-matched male collegiate students. The modified N-K table was used for isometric strength measurement(unit: N). Mann-Whitney tests were performed to determine the differences in the H/Q ratios of soccer players and age-matched students at different knee flexion angles of the dominant leg. The strength of the hamstring muscle in the study group was significantly lower than that observed in the control group at knee flexion angles of $60^{\circ}$ (p<.001), $90^{\circ}$ (p<.01), and $120^{\circ}$ (p<05). The strength of the quadriceps muscle in the study group was significantly higher than that observed in the control group at flexion angles of $30^{\circ}$ (p<.001) and $60^{\circ}$ (p<.05). The H/Q ratios in the study and control groups differed significantly at all angles ($60^{\circ}$, p<.001, $90^{\circ}$, p<.001 and $120^{\circ}$, p<.001).

• Journal of The Korean Society of Integrative Medicine
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• v.5 no.3
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• pp.49-55
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• 2017

Purpose: The purpose of this study was to investigate effect of open kinetic chain exercise on the motor function of the lower limb in middle school soccer players. Method: The subjects consisted of 14 soccer players who attend middle school in Gwangju. All subjects received open kinetic chain exercise for 3 weeks. The muscle strength of the ankle was measured by a commander muscle tester. Postural control ability was measured using a hopping test. All measurements for each subject were conducted pre-intervention and 3 weeks post-intervention. Result: There were significant differences post-intervention in the muscle strength and-the postural control ability of the open kinetic chain exercise group(p<.05). Conclusion: Open kinetic chain exercise had a significant positive effect on the motor function of the lower limb in soccer players. Therefore, open kinetic chain exercise may prevent and resolve injury with careful management while soccer players are training or playing games. It could be helpful to extend the lives of athletes and improve their records.

• Journal of the Korean Academy of Clinical Electrophysiology
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• v.10 no.1
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• pp.45-52
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• 2012

Purpose : This study is carried out to investigate the effect of asymmetric exercises on soccer players' vertebral abnormality and weight bearing. Methods : A total of 40 soccer players were divided into either a group of 20 players who use a unilateral foot or a group of 20 players who use both feet. 3-dimensional spine structure analyzer was used to analyze body inclination, pelvic inclination, pelvic torsion, turning of spinal segment, spinal curvature, thoracic kyphosis curvature, lumbar lordosis curvature, left/right weight distribution, and front/back weight distribution. Results : The result of the two groups showed that there were significant differences (p<0.05) for every item except turning of spinal segment and lumbar lordosis curvature. Conclusion : From this result, we can find that spinal and pelvic deformity and body weight are unilaterally supported for soccer players with asymmetric exercises.

• Proceedings of the IEEK Conference
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• 2000.07b
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• pp.727-730
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• 2000

Recently, RoboCup soccer simulation has been regarded as a good benchmark problem for multiagent researches. Soccer agents have to make decision based on visual and auditory information, which are sent from the soccer server. In order to develop a strong team, we have to design decision-making process of each player agent. However, it is very difficult for us to design the decision-making processes in detail, because we don't know what actions of each player are effective for the team. In this paper, we attempt to apply co-evolutionary method, which is one type of analogies of evolution, to improve the team play. Agents have hand coded basic skills, which include dribble, shoot, pass etc. Agents already can play autonomously and independently. Individual agent skills are characterized by some parameters. By coevolving teams with these parameters, we obtained relatively interesting teams, in which players behave cooperatively in order to win the soccer game. From some experiments, we discuss what teams are evolved.

• PNF and Movement
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• v.18 no.1
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• pp.87-95
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• 2020

Purpose: The purpose of this study was to investigate the effect of whole-body vibration training on the flexibility and agility of professional soccer players. Methods: Sixteen professional soccer players participated voluntarily in the study. Subjects were allocated to two groups: the experimental group received whole-body vibration (WBV) and team training, and the control group received only team training. Team training was conducted in 15 sessions of 70 min duration over 3 weeks. WBV training was applied at 40 Hz frequency, 5 sets (1 min-training, 1 min-resting) in a squatting position. Outcomes from sit-and-reach, side-step test, burpee test, and T-test were measured before and after training. To examine pre- and post-intervention differences between the two groups, a paired t-test was used. Independent t-tests were performed to compare pre- and post-test scores and the time difference of the two groups. Results: Significant improvements in sit-and-reach and agility variables were observed in the experimental group (p < 0.05). In particular, flexibility (sit-and-reach) and agility (the side-step test and the burpee test) were significantly different between the two groups (p < 0.05). Conclusion: These findings suggest that whole-body vibration training has a positive effect on performance enhancement for professional soccer players.

• Advances in Computational Design
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• v.7 no.4
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• pp.297-319
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• 2022

Due to their natural and social revelation, also their ease and flexibility, human collective behavior and teamwork sports are inspired to introduce optimization algorithms to solve various engineering and scientific problems. Nowadays, meta-heuristic algorithms are becoming some striking methods for solving complex real-world problems. In that respect in the present study, the authors propose a novel meta-innovative algorithm based on soccer teamwork sport, suitable for optimization problems. The method may be referred to as the Soccer League Optimization-based Championship Algorithm, inspired by the Soccer league. This method consists of two main steps, including: 1. Qualifying competitions and 2. Main competitions. To evaluate the robustness of the proposed method, six different benchmark mathematical functions, and two engineering design problem was performed for optimization to assess its efficiency in achieving optimal solutions to various problems. The results show that the proposed algorithm may well explore better performance than some well-known algorithms in various aspects such as consistency through runs and a fast and steep convergence in all problems towards the global optimal fitness value.

• Journal of Sport and Applied Science
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• v.7 no.4
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• pp.13-18
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• 2023

Purpose: This study aims to determine what changes occur in body composition and performance by subjecting youth soccer players to weight training and combined training, which are known to be effective in improving anaerobic capacity, for 6 weeks. Research design, data, and methodology: This study was conducted on 30 high school soccer players from S City who had no current injuries or medical problems and had been registered as players with the Korea Football Association for more than 3 years. Subjects were divided into a weight training group (WTG, n=15) and a combined training group (CTG, n=15). Training lasted 6 weeks, and measurements were taken before and after training. Mean (M) and standard deviation (SD) were calculated to present the descriptive statistics of all dependent variables. Paired t-tests were used to test for within-group differences. Further, Independent t-tests were employed to test for between-group differences. Results: In terms of body composition, height significantly increased in WTG and CTG, and body fat percentage significantly decreased in CTG. As for performance, WTG's 20m sprint record decreased significantly. Conclusion: As a result, this study confirmed that weight training improved the 20m sprint ability of youth soccer players. Future research could provide more useful information by extending the study period and incorporating the physical characteristics of adolescents.

• 제어로봇시스템학회:학술대회논문집
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• 1997.10a
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• pp.648-651
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• 1997

This paper proposes methods for the cooperative control of multiple mobile robots and constructs a robotic soccer system in which the cooperation will be implemented as a pass play of two robots. To play a soccer game, elementary actions such as shooting and moving have been designed, and Q-learning, which is one of the popular methods for reinforcement learning, is used to determine what actions to take. Through simulation, learning is successful in case of deliberate initial arrangements of ball and robots, thereby cooperative work can be accomplished.

• Proceedings of the IEEK Conference
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• 2008.06a
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• pp.1169-1170
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• 2008

The paper is represented active robot soccer system using humanoid. many robot we implement the control method of several robot and the algorithm of robot soccer system.