Vision provides relevant information for safe locomotion in a variety of environments. During stair locomotion visual information may be important to detect step boundaries, transitions between ground level and stairs, handrail location, and potential hazards. Although there is a large body of literature on the role of vision during locomotion there is relatively little focused on how visual information is used during stair walking. Stairs are related to a significant number of accidents in daily living, and many of these accidents are attributed to visual factors. Therefore, understanding the role of vision during stair walking could provide insight into the mechanisms involved in stair accidents. The purpose of this thesis was to investigate the properties of the visual input used to guide locomotion on stairs. Study 1 was design to describe the gaze patterns during stair locomotion with a specific focus on transitions and handrails. Study 2 investigated the effects of performing concurrent visual and non-visual tasks on walking performance and associated gaze behaviour during stair ascent. Study 3 explored the role of peripheral visual information during visual and non-visual dual tasking. Finally, Study 4 investigated the effects of restricting the lower peripheral visual field to walk on stairs. Studies relied on the measurement in health young adults of: gaze behaviour using an eye tracker, temporal characteristics of walking using foot switches, and reaction time and errors of dual task performance. Overall, the findings of these studies highlight the importance of the lower visual field in guiding stair locomotion and the specific importance for stair transitions. Moreover, foveal vision is not specifically critical to detecting handrails or steps. Results are interpreted in the light of the specialization of the dorsal ventral stream in processing peripheral visual field information. Findings of this thesis provide basic understanding on the role of vision for stair navigation with potential applications in stair-related accident prevention programs and stair design.

Vision provides relevant information for safe locomotion in a variety of environments. During stair locomotion visual information may be important to detect step boundaries, transitions between ground level and stairs, handrail location, and potential hazards. Although there is a large body of literature on the role of vision during locomotion there is relatively little focused on how visual information is used during stair walking. Stairs are related to a significant number of accidents in daily living, and many of these accidents are attributed to visual factors. Therefore, understanding the role of vision during stair walking could provide insight into the mechanisms involved in stair accidents. The purpose of this thesis was to investigate the properties of the visual input used to guide locomotion on stairs. Study 1 was design to describe the gaze patterns during stair locomotion with a specific focus on transitions and handrails. Study 2 investigated the effects of performing concurrent visual and non-visual tasks on walking performance and associated gaze behaviour during stair ascent. Study 3 explored the role of peripheral visual information during visual and non-visual dual tasking. Finally, Study 4 investigated the effects of restricting the lower peripheral visual field to walk on stairs. Studies relied on the measurement in health young adults of: gaze behaviour using an eye tracker, temporal characteristics of walking using foot switches, and reaction time and errors of dual task performance. Overall, the findings of these studies highlight the importance of the lower visual field in guiding stair locomotion and the specific importance for stair transitions. Moreover, foveal vision is not specifically critical to detecting handrails or steps. Results are interpreted in the light of the specialization of the dorsal ventral stream in processing peripheral visual field information. Findings of this thesis provide basic understanding on the role of vision for stair navigation with potential applications in stair-related accident prevention programs and stair design.

Thesis (Ph. D.)--University of Wisconsin--Madison, 1969. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.

Thesis (M.S. in Modeling, Virtual Environments and Simulation)--Naval Postgraduate School, March 2005. / Thesis Advisor(s): Rudolph Darken. Includes bibliographical references (p. 59-61). Also available online.

Thesis (M.S.)--Ohio State University, 1985. / Includes bibliographical references (leaves 101-103). Available online via OhioLINK's ETD Center

Both bird and fish locomotion are thought to be more efficient than the equivalent man-made vehicles driven by propellers/impellers and jet engines. Through studies that decompose the different kinematic and shape effects of these biological systems, we can understand what leads to their high cruising performance and efficiency. Two major studies were conducted. The first was on the effect of different kinematic parameters of large soaring birds on flight performance and the second was on the effect of caudal fin shape on the performance of thunniform swimmers. For the first study on flight performance, flapping, folding, and twist were the wing motions of interest. The second study on swimming performance observed how caudal fin sweep angle affects propulsion while isolating the effect of this shape difference from aspect ratio and area effects. Low order models were primarily used to conduct the bird flight study, though experimental methods were investigated as well. The thunniform swimming study was conducted through experimentation on a biomimetic system. The flight study found that, under the right circumstances, both wing twist and wing folding have a positive effect on flight performance. However, the impact of wing twist is much larger. To incorporate this wing twist into a robotic system, a new reduced order model that partially accounts for 3D effects was developed and validated. In the future, this model can be used in conjunction with a flight controller to control wing twist. The swimming study found that caudal fin sweep had a significant impact on performance, moderately swept fins showing the greatest improvement. Using an overly large sweep angle led to diminished performance when compared to the moderately swept fins, but still demonstrated improved performance over a non-swept fin. The increased performance of the moderately swept fins was due to how it affected LEV formation and stability. / Ph. D. / Bird flight and fish swimming are thought to be more efficient than drones and submersible vehicles respectively. By conducting studies on the motion of the wing and the shape of the tail fin, we can gain a better understanding of how to produce efficient vehicles that are inspired by fish/birds. Two major studies were conducted. The first study analyzed the wing motion of birds such as seagulls. The three most important wing motions were analyzed using fast computational simulations. Functional flapping aircraft that can be used in future studies were also constructed. The second study analyzed the tail fin shape of tuna, specifically how the swept shape affects propulsion performance. This study was conducted by operating a robotic tuna with interchangeable tails in a water tunnel. The computational studies on wing motion showed that controlling twist of the wing in addition to typical flapping motion could greatly improve performance of a flapping bird-like aerial vehicle. To incorporate this wing twist into a future system, a mathematical model that provided aerodynamic predictions was developed. This model can be used in conjunction with a controller to provide efficient real time control of the wing twist. The experimental swimming study found that fin sweep had a significant impact on performance. Using a moderately swept fin (25-35 degrees) increases thrust production without increased energy expenditure. Fins with greater sweep angles start to yield diminished performance benefits. Using an elliptical area distribution can also lead to increased performance.

Dix-sept sujets sains marchaient sur un tapis roulant avant, pendant et après une exposition, de durée variable (49-1629 cycles de marche), à un champ de force perturbant la marche, appliqué à la jambe par un élastique (2 jours consécutifs). Le but était de voir l'effet de la durée d'exposition au champ de force élastique sur le contrôle de la jambe durant la locomotion. Avec l'élastique, une erreur initiale était observée dans la vitesse maximale du premier orteil puis les suj ets adaptaient graduellement leur patron de marche (vitesse de l'orteil, activité musculaire). Au jour 1, après le retrait de la force, une persistance temporaire du patron modifié était observée. Les sujets ayant été exposés plus longtemps à l'élastique maintenaient ce patron plus longtemps. Au jour 2, avec l'élastique, les sujets avaient significativement réduit l'erreur initiale de la vitesse de l'orteil indépendamment de la durée d'exposition du jour 1. Ces résultats suggèrent que, lors de la marche dans un champ de force, une exposition de courte durée (2: 49 cycles de marche) semble suffisante pour obtenir un ajustement des paramètres locomoteurs et une rétention de ceux-ci lors d'une deuxième exposition.

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