Humanoid Robot Soccer Locomotion and Kick Dynamics: Open Loop Walking, Kicking and Morphing into Special Motions on the Nao Robot

Striker speed and accuracy in the RoboCup (SPL) international robot soccer league is becoming increasingly important as the level of play rises. Competition around the ball is now decided in a matter of seconds. Therefore, eliminating any wasted actions or motions is crucial when attempting to kick the ball. It is common to see a discontinuity between walking and kicking where a robot will return to an initial pose in preparation for the kick action. In this thesis we explore the removal of this behaviour by developing a transition gait that morphs the walk directly into the kick back swing pose. The solution presented here is targeted towards the use of the Aldebaran walk for the Nao robot. The solution we develop involves the design of a central pattern generator to allow for controlled steps with realtime accuracy, and a phase locked loop method to synchronise with the Aldebaran walk so that precise step length control can be activated when required. An open loop trajectory mapping approach is taken to the walk that is stabilized statically through the use of a phase varying joint holding torque technique. We also examine the basic princples of open loop walking, focussing on the commonly overlooked frontal plane motion. The act of kicking itself is explored both analytically and empirically, and solutions are provided that are versatile and powerful. Included as an appendix, the broader matter of striker behaviour (process of goal scoring) is reviewed and we present a velocity control algorithm that is very accurate and efficient in terms of speed of execution

Penalty Kick of a Humanoid Robot by a Neural-Network-Based Active Embedded Vision System

[[abstract]]This paper realizes the humanoid robotic system to execute the penalty kick (PK) of the soccer game. The proposed system includes the following three subsystems: a humanoid robot (HR) with 22 degree-of-freedom, a soccer with different colors, and a soccer gate. In the beginning, the HR scans the soccer field to find the gate and the soccer, which are randomly distributed in a specific region in the front of the gate. If a command for the PK of the soccer with specific color is assigned, the HR will be navigated by an active embedded vision system (AEVS). After the HR reaches a planned position and posture, the PK of the HR will be executed. Two key important techniques are developed and integrated into the corresponding task. One is the modeling using multilayer neural network (MNN) for different view angles, the other is the visual navigation strategy for the PK of the HR. In addition, the error sensitivities in the pan and tilt directions of these four visible regions are analyzed and compared. The proposed strategy of the visual navigation includes the following two parts: (i) the switched visible regions are designed to navigate the HR to the planned position, and (ii) the posture revision of the HR in the neighborhood of the soccer in order to execute the PK. Finally, a sequence of experiments for the PK of the HR confirm the effectiveness and efficiency of the propose methodology.[[conferencetype]]國際[[conferencelocation]]Taipei, Taiwa

Analysis of the backpack loading efects on the human gait

Gait is a simple activity of daily life and one of the main abilities of the human being. Often during leisure, labour and sports activities, loads are carried over (e.g. backpack) during gait. These circumstantial loads can generate instability and increase biomechanicalstress over the human tissues and systems, especially on the locomotor, balance and postural regulation systems. According to Wearing (2006), subjects that carry a transitory or intermittent load will be able to find relatively efficient solutions to compensate its effects.info:eu-repo/semantics/publishedVersio

Robust execution of bipedal walking tasks from biomechanical principles

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2006.Includes bibliographical references (p. 348-352).Effective use of robots in unstructured environments requires that they have sufficient autonomy and agility to execute task-level commands successfully. A challenging example of such a robot is a bipedal walking machine. Such a robot should be able to walk to a particular location within a particular time, while observing foot placement constraints, and avoiding a fall, if this is physically possible. Although stable walking machines have been built, the problem of task-level control, where the tasks have stringent state-space and temporal requirements, and where significant disturbances may occur, has not been studied extensively. This thesis addresses this problem through three objectives. The first is to devise a plan specification where task requirements are expressed in a qualitative form that provides for execution flexibility. The second is to develop a task-level executive that accepts such a plan, and outputs a sequence of control actions that result in successful plan execution. The third is to provide this executive with disturbance handling ability. Development of such an executive is challenging because the biped is highly nonlinear and has limited actuation due to its limited base of support. We address these challenges with three key innovations.(cont.) To address the nonlinearity, we develop a dynamic virtual model controller to linearize the biped, and thus, provide an abstracted biped that is easier to control. The controller is model-based, but uses a sliding control technique to compensate for model inaccuracy. To address the under-actuation, our system generates flow tubes, which define valid operating regions in the abstracted biped. The flow tubes represent sets of state trajectories that take into account dynamic limitations due to under-actuation, and also satisfy plan requirements. The executive keeps trajectories in the flow tubes by adjusting a small number of control parameters for key state variables in the abstracted biped, such as center of mass. Additionally, our system uses a novel strategy that employs angular momentum to enhance translational controllability of the system's center of mass. We evaluate our approach using a high-fidelity biped simulation. Tests include walking with foot-placement constraints, kicking a soccer ball, and disturbance recovery.by Andreas G. Hofmann.Ph.D

Robust Execution of Bipedal Walking Tasks From Biomechanical Principles

PhD thesisEffective use of robots in unstructured environments requires that they have sufficient autonomy and agility to execute task-level commands successfully. A challenging example of such a robot is a bipedal walking machine. Such a robot should be able to walk to a particular location within a particular time, while observing foot placement constraints, and avoiding a fall, if this is physically possible. Although stable walking machines have been built, the problem of task-level control, where the tasks have stringent state-space and temporal requirements, and where significant disturbances may occur, has not been studied extensively. This thesis addresses this problem through three objectives. The first is to devise a plan specification where task requirements are expressed in a qualitative form that provides for execution flexibility. The second is to develop a task-level executive that accepts such a plan, and outputs a sequence of control actions that result in successful plan execution. The third is to provide this executive with disturbance handling ability.Development of such an executive is challenging because the biped is highly nonlinear and has limited actuation due to its limited base of support. We address these challenges with three key innovations. To address the nonlinearity, we develop a dynamic virtual model controller to linearize the biped, and thus, provide an abstracted biped that is easier to control. The controller is model-based, but uses a sliding control technique to compensate for model inaccuracy. To address the under-actuation, our system generates flow tubes, which define valid operating regions in the abstracted biped. The flow tubes represent sets of state trajectories that take into account dynamic limitations due to under-actuation, and also satisfy plan requirements. The executive keeps trajectories in the flow tubes by adjusting a small number of control parameters for key state variables in the abstracted biped, such as center of mass. Additionally, our system uses a novel strategy that employs angular momentum to enhance translational controllability of the systemÂs center of mass. We evaluate our approach using a high-fidelity biped simulation. Tests include walking with foot-placement constraints, kicking a soccer ball, and disturbance recovery

A biomechanical analysis of non-linear motion in soccer

Soccer consists of many different types of sports specific movement. The present level of understanding of non-linear motion is negligible yet required if improvements are to be made in technique and performance of such actions. This thesis aimed to establish mechanisms for non-linear motion relevant to soccer performance. Preliminary analysis of curvilinear motion involved electromyographical analysis in selected muscles of the lower extremity at different grades of curvature. Results revealed adaptation of temporal muscle activity at the tightest grade of curvature. Adaptation occurred in both legs, but predominantly the outside leg, with increased duration of activity after footstrike (Smith et al., 1997). Stride kinematics were also altered, as increasing curve severity gave reduced stride length and increased stride frequency. Foot contact time was not changed as a function of curvilinear motion (P > 0.05), giving an increased proportion of the stride cycle in the stance phase. Rear foot contact time increased as a function of curve severity (P $ 0.05). To describe and quantify adaptation of lower limb movement in curvilinear motion, three-dimensional kinematics were used. Subjects (n = 8) wore soccer footwear on natural turf. Ranges of motion at the lower extremity were increased at the faster of the two velocities tested (4.4 and 5.4 ms·] ± 5%), yet tended to reduce with curve severity. The inside leg displayed more differences in angular displacement with curve severity, and the ankle joint showed to be a key adaptive site. Ground reaction forces of two consecutive footfalls were performed on natural turf to assess relative contributions of the two limbs during straight and curvilinear motion at a 5m radius. Total force over two footfalls was greater during straight motion. A mechanism of lowered centre of gravity during curvilinear motion was proposed. During curvilinear motion the outside leg was associated with greater force values in all three planes, displaying a greater contribution to curvilinear motion. Force measurements on natural turf were used to assess different sole configuration during three soccer specific moves. A modern moulded sole was found to be associated with greater maximum friction, also lower vertical ground reaction forces during a Cruyff turn and lower overall forces during the shot. This thesis established biomechanical adaptations and suggested mechanisms during non-linear motion in the soccer player. The research represented the first experimental investigations in this area and therefore recommendations for future study are considered

Is the dimension of the proximal aponeurosis of biceps femoris long head a risk factor for a strain injury?

Purpose: To determine i) the reliability of a semi-automated tracking method to quantify the BFlhApo (biceps femoris long head proximal aponeurosis) size (i.e area interface, average width, volume, and length) based on MRI (magnetic resonance imaging) data; and, ii) to examine if the BFlhApo size of elite footballers with history of BFlh (biceps femoris long head) injury differed compared to matched controls without a previous BFlh injury. Methods: Forty individuals performed a MRI in both thighs (31 with no BFlh strain history and 9 with a BFlh strain history) during the preseason period. To measure more precisely the BFlhApo size, a semi-automated tracking method was built and tested (intra- and inter-rater reliability). Comparisons of the BFlhApo size between thighs with history of BFlh injury (experimental group) and non-injured thighs (control group) were set, as well as in between groups (injured vs non injured; left vs right). Results: The analysis of the reliability using the semi-automated tracking method showed a good intra-rater and inter-rater reliability (ICC between 0.75 and 0.9, at 95% confidence interval). No statistically significant differences (P <0.05) were found in the BFlhApo size regarding to all thighs comparisons. Conclusions: A reliable measurement procedure was able to better quantify BFlhApo dimensions between individuals with and without history of BFlh injury. Individuals with history of BFlh injury suggest no significant differences in their BFlhApo dimensions compared to individuals without this history. Thus, it seems inappropriate to state that a smaller BFlhApo size is an independent risk factor for developing a BFlh injury.Objetivo: Determinar: i) a fiabilidade de um método de rastreamento semiautomático para quantificar o tamanho da BFlhApo (aponevrose proximal da longa porção do bicípite femoral) com base em imagens de ressonância magnética; e, ii) examinar se o tamanho da BFlhApo (i.e. área de interface, largura média, volume e comprimento) de futebolistas de elite com história de lesão da BFlh (longa porção do bicípite femoral) difere em comparação com um grupo de controlo, sem historial de lesão da BFlh. Método: Quarenta sujeitos realizaram ressonância magnética em ambas as coxas (31 sem história de lesão da BFlh e 9 com história de lesão da BFlh) durante o período de pré-época. Para medir com mais precisão o tamanho da BFlhApo, um método de rastreamento semiautomático foi desenvolvido e testado (fiabilidade intra e inter examinador). Comparações do tamanho da BFlhApo entre as coxas com história de lesão da BFlh (grupo experimental) e coxas não lesionadas (do grupo controlo) foram estabelecidas, bem como dentro dos grupos (lesionado vs. não lesionado; esquerdo vs. direito). Resultados: A análise da fiabilidade do método de rastreamento semiautomatizado mostrou uma boa fiabilidade intra examinador e interobservador (ICC entre 0,75 e 0,9, com intervalo de confiança de 95%). Não foram encontradas diferenças estatisticamente significativas (P <0,05) no tamanho da BFlhApo em relação a todas as comparações estabelecidas. Conclusões: Um procedimento de medição fiável foi capaz de quantificar melhor as dimensões da BFlhApo entre indivíduos com e sem histórico de lesão da BFlh. Indivíduos com histórico de lesão da BFlh sugerem não apresentar diferenças significativas nas dimensões da sua BFlhApo relativamente a indivíduos sem este histórico. Assim, parece desajustado afirmar que uma menor dimensão da BFlhApo seja fator de risco independente para desenvolver uma lesão da BFlh