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京都大学 / 新制・課程博士 / 博士(人間健康科学) / 甲第23830号 / 人健博第101号 / 新制||人健||7(附属図書館) / 京都大学大学院医学研究科人間健康科学系専攻 / (主査)教授 青山 朋樹, 教授 市橋 則明, 教授 宮本 享 / 学位規則第4条第1項該当 / Doctor of Human Health Sciences / Kyoto University / DFAM

Locomotion, moving around in our complex world is as crucial to many animals as finding food, shelter or a mate. The intricate interplay between the brain, nerves, muscles, tendons and bones allows for a variety of gaits. Animal movement has been studied in many environments like water, land or air, often focusing on one habitat alone. These studies were crucial in establishing the principles of animal locomotion, but don’t always reflect the intricate lifestyle of an animal. More often then not, animals will encounter different surface structures (such as grass, sand, soil, forest debris) or even interact between different habitats, such as at the water-land interface. Fewer studies have focused on understanding how movement changes when physical conditions vary. A turtle swimming in a dense, buoyancy-dominated water habitat transitioning to a walking on gravity-dominated terrestrial habitat is poorly understood and may open insight into new locomotor strategies. Turtles are an interesting study subject to study water-land transitions, as their spines are fused to their carapace, isolating any movement generation to their limbs only. In this thesis, I chose different size red-eared slider (Trachemys scripta elegans) turtles to investigate their locomotion during discreet water depth, as well as during shallow water locomotion and investigated whether bone shape can be predictive of the environment they live in. / Biology

Tensegrity structures consist of isolated compression members (rigid bars) suspended by a continuous network of tension members (cables). Tensegrity structures can be used as variable geometry truss (VGT) mechanisms by actuating links to change their length. This paper will present a new method of position finding for tensegrity structures that can be used for actuation as VGT mechanisms. Tensegrity structures are difficult to understand and mathematically model. This difficulty is primarily because tensegrity structures only exist in specific stable tensegrity positions. Previous work has focused on analysis based on statics, dynamics, and virtual work approaches. This work considers tensegrity structures from a kinematic viewpoint. The kinematic approach leads to a better understanding of the conditions under which tensegrity structures exist in the stable positions. The primary understanding that comes from this kinematic analysis is that stable positions for tensegrity structures exist only on the boundaries of nonassembly of the structure. This understanding also allows the tensegrity positions to be easily found. This paper presents a method of position finding based on kinematic constraints and applies that method to several example tensegrity structures. / Master of Science

INTRODUCTION: ACL-reconstructed (ACL-R) patients exhibit side-to-side asymmetries in movement and loading patterns after surgery, some of which are predictive of a secondary ACL injury. These asymmetries have not been fully assessed in healthy athletes. PURPOSE: To quantify side-to-side symmetry in secondary injury predictors in healthy athletes and compare these metrics to those measured in previous cohorts of ACL-R patients, as well as to assess differences in these metrics between two landing tasks and between sexes. METHODS: 60 healthy recreational athletes performed seven trials of a stop-jump task and seven trials of a single-leg hop for distance on each limb. The kinematics and kinetics of the first landing of the stop-jump and the landing of the single-leg hop were analyzed with a 10-camera motion analysis system (240Hz) and 2 embedded force plates (1920Hz). Limb symmetry indices (LSIs) were calculated for each variable and compared between subject groups, tasks, and sexes with Wilcoxon Signed Rank tests (p<0.05). RESULTS: Control subjects exhibited asymmetry in hop distance (p=0.006). ACL-R subjects displayed greater asymmetry in knee flexion variables, peak forces, and peak knee extension moments during the bilateral landing (p<0.001) and in hop distance (p<0.001). Control subjects showed greater asymmetry in knee flexion variables during the single-leg hop (p<0.001). Males and females showed similar symmetry in both tasks. CONCLUSIONS: Symmetry cannot be assumed in control subjects in all metrics. Asymmetries are more prevalent in ACL-R athletes than in healthy controls. Future work will continue to examine the usefulness of each metric in assessing ACL-R rehabilitation. / Master of Science

This work bridges the gap between theory and practice. The development of general inverse kinematic solution techniques is new, hence few detailed applications of these methods exist. Before methods such as these were available, most commercial manipulators were designed to be geometrically simple, yielding 4th or lower degree governing equations. With the further development and application of these techniques, industry will be capable of implementing more complex manipulators for highly specialized tasks. A general inverse kinematic analysis technique is applied to an industrial manipulator designed for the inspection of nuclear reactor vessels. The analysis is performed by solving the 16th degree univariate displacement polynomial of the general six-degree-of-freedom arm using an equivalent seven-degree-of-freedom closed-loop spatial chain. All possible combinations of joint angles for a given hand position and orientation are obtained. A region in which the manipulator has the maximum number of solutions is used as a numerical example. The inverse kinematic analysis was programmed in C, which is included in Appendix D. / Master of Science

Three discrete-time adaptive controllers are developed and applied to Four-bar linkage velocity control to reduce the input link velocity fluctuations without compromising the control system velocity transient response. The successful control techniques use the known mechanism kinematics and the mechanism input link position to control the nonlinear mechanism dynamics. The study shows that the adaptive controls are feasible to implement using current microprocessor technology, and the velocity control performance is improved when compared to an industry-standard analog servomotor control. However, more development is required to realize the full potential of the adaptive control technique. A nonlinear Four-bar dynamic model is developed using Kinematic Influence Coefficients. This model is used to develop the adaptive controls and to computer simulate the control scheme performances. The simulated model velocity response is compared qualitatively to experimental data and shown to be similar to an experimental device. / Master of Science

This thesis presents two studies related to head injury. The study presented in Chapter 1 reviewed findings of cranial movement in animal and human specimens and evaluate the validity of cranial movement due to manual manipulation in humans through engineering analysis. The study had two parts. In Part I, the literature was reviewed to determine the cranial motion in animals and humans. Engineering analysis was done in Part II to determine the amount of force necessary to cause cranial motion in the studies from Part I using skull stiffness values from published studies. Chapter 2 explored data collection methodologies used in frontal sled tests. Several data collection methodologies exist for collecting kinematic data, such as Vicon motion analysis, video analysis, and sensors. Head trajectories from motion data and accelerometer data were plotted up to maximum forward excursion of the head for eight frontal sled tests, four conducted at Virginia Tech and four at the University of Virginia. In addition, the percent difference between maximum forward excursion values from sensor and motion data were calculated. Finally, Chapter 3 discusses the literary contributions of each study and to which journals they will be submitted. / Master of Science