Matching Items (40)
Description
In this work, different passive prosthetic ankles are studied. It is observed that complicated designs increase the cost of production, but simple designs have limited functionality. A new design for a passive prosthetic ankle is presented that is simple to manufacture while having superior functionality. This prosthetic ankle design has two springs: one mimicking Achilles tendon and the other mimicking Anterior-Tibialis tendon. The dynamics of the prosthetic ankle is discussed and simulated using Working model 2D. The simulation results are used to optimize the springs stiffness. Two experiments are conducted using the developed ankle to verify the simulation It is found that this novel ankle design is better than Solid Ankle Cushioned Heel (SACH) foot. The experimental data is used to find the tendon and muscle activation forces of the subject wearing the prosthesis using OpenSim. A conclusion is included along with suggested future work.
ContributorsBhat, Sandesh Ganapati (Author) / Redkar, Sangram (Thesis advisor) / Sugar, Thomas (Committee member) / Lee, Hyuglae (Committee member) / Marvi, Hamid (Committee member) / Arizona State University (Publisher)
Created2017
Description
The Basilisk lizard is known for its agile locomotion capabilities on granular and aquatic media making it an impressive model organism for studying multi-terrain locomotion mechanics. The work presented here is aimed at understanding locomotion characteristics of Basilisk lizards through a systematic series of robotic and animal experiments. In this work, a Basilisk lizard inspired legged robot with bipedal and quadrupedal locomotion capabilities is presented. A series of robot experiments are conducted on dry and wet (saturated) granular media to determine the effects of gait parameters and substrate saturation, on robot velocity and energetics. Gait parameters studied here are stride frequency and stride length. Results of robot experiments are compared with previously obtained animal data. It is observed that for a fixed robot stride frequency, velocity and stride length increase with increasing saturation, confirming the locomotion characteristics of the Basilisk lizard. It is further observed that with increasing saturation level, robot cost of transport decreases. An identical series of robot experiments are performed with quadrupedal gait to determine effects of gait parameters on robot performance. Generally, energetics of bipedal running is observed to be higher than quadrupedal operation. Experimental results also reveal how gait parameters can be varied to achieve different desired velocities depending on the substrate saturation level. In addition to robot experiments on granular media, a series of animal experiments are conducted to determine and characterize strategies
exhibited by Basilisk lizards when transitioning from granular to aquatic media.
exhibited by Basilisk lizards when transitioning from granular to aquatic media.
ContributorsJayanetti, Vidu (Author) / Marvi, Hamid (Thesis advisor) / Emady, Heather (Committee member) / Lee, Hyunglae (Committee member) / Arizona State University (Publisher)
Created2018
Description
Robotic swarms can potentially perform complicated tasks such as exploration and mapping at large space and time scales in a parallel and robust fashion. This thesis presents strategies for mapping environmental features of interest – specifically obstacles, collision-free paths, generating a metric map and estimating scalar density fields– in an unknown domain using data obtained by a swarm of resource-constrained robots. First, an approach was developed for mapping a single obstacle using a swarm of point-mass robots with both directed and random motion. The swarm population dynamics are modeled by a set of advection-diffusion-reaction partial differential equations (PDEs) in which a spatially-dependent indicator function marks the presence or absence of the obstacle in the domain. The indicator function is estimated by solving an optimization problem with PDEs as constraints. Second, a methodology for constructing a topological map of an unknown environment was proposed, which indicates collision-free paths for navigation, from data collected by a swarm of finite-sized robots. As an initial step, the number of topological features in the domain was quantified by applying tools from algebraic topology, to a probability function over the explored region that indicates the presence of obstacles. A topological map of the domain is then generated using a graph-based wave propagation algorithm. This approach is further extended, enabling the technique to construct a metric map of an unknown domain with obstacles using uncertain position data collected by a swarm of resource-constrained robots, filtered using intensity measurements of an external signal. Next, a distributed method was developed to construct the occupancy grid map of an unknown environment using a swarm of inexpensive robots or mobile sensors with limited communication. In addition to this, an exploration strategy which combines information theoretic ideas with Levy walks was also proposed. Finally, the problem of reconstructing a two-dimensional scalar field using observations from a subset of a sensor network in which each node communicates its local measurements to its neighboring nodes was addressed. This problem reduces to estimating the initial condition of a large interconnected system with first-order linear dynamics, which can be solved as an optimization problem.
ContributorsRamachandran, Ragesh Kumar (Author) / Berman, Spring M (Thesis advisor) / Mignolet, Marc (Committee member) / Artemiadis, Panagiotis (Committee member) / Marvi, Hamid (Committee member) / Robinson, Michael (Committee member) / Arizona State University (Publisher)
Created2018
Description
While there is extensive information available about organizations that receive donated organs for transplant, much less is known about those that accept tissue and whole bodies for medical education and research. Throughout the United States, nontransplant anatomical donation organizations exist within an ambiguous sector of the donation industry, unencumbered by federal regulations. Although these companies adhere to the Uniform Anatomical Gift Act, the lack of a single entity responsible for overseeing their operations has led to public skepticism and animosity among competing businesses. Legislation has the potential to legitimize the industry. For it to be successful, however, the intricacies of a complex market that deals directly with the movement of human remains and intangible issues of human integrity and morality, must be thoroughly understood.
ContributorsGlynn, Emily Sanders (Author) / Brian, Jennifer (Thesis director) / Fisher, Rebecca (Committee member) / Barrett, The Honors College (Contributor) / School of Nutrition and Health Promotion (Contributor) / Department of English (Contributor)
Created2015-05
Description
The role of robotics mobility is essential in the world of research because it allows humans to perform jobs that are dull, dirty, or dangerous without being physically present. A typical robot environment is one that is smooth and predictable. Screw-powered vehicles (SPV's) have commonly been used in these predictable environment situations such as terrestrial applications like mud and snow. However, a gap remains in SPV's traversing complex environments, particularly debris and granular material. The goal is to study the characteristics of how a SPV might move and generate force in such a granular environment for Earth and space. In our study, the chosen granular environment is soda-lime glass beads for easy characterization. This study with glass beads focuses on two separate approaches. The first approach is using a single screw rotating while the apparatus remains static and analyzing the forces that impact the screw. The second approach includes using a full body craft with two double helix screws and analyzing the translational velocity of the craft. This study presents both experimental and computational results using simulations with Multi-Body Dynamics (MBD) and Discrete Element Method (DEM) software packages to investigate the trends of SPV's in a granular environment.
ContributorsRamirez, Sierra Monique (Author) / Marvi, Hamid (Thesis director) / Emady, Heather (Committee member) / Thoesen, Andrew (Committee member) / Mechanical and Aerospace Engineering Program (Contributor) / Barrett, The Honors College (Contributor)
Created2018-05
Description
The ringtail (Bassariscus astutus), a member of the Procyonidae, is capable of 180 degrees of hindlimb reversal during headfirst descent down a vertical substrate. The goal of this study was to determine the presence or absence of myological adaptations related to hindlimb reversal in the ringtail. Data for B. astutus are presented, including muscle weights and muscle maps ascertained from the dissection of four hindlimbs. Data from the current study were compared to published accounts of other species capable of hindlimb reversal, including procyonids (raccoon, coati, kinkajou, olingo), a mustelid (marten), palm civet, mongoose, tree squirrel, common tree shrew, and slow loris. Muscle mass data from this study demonstrate that the hip adductors of scansorial mammals are significantly more robust than those of terrestrial mammals, indicating a myological adaptation for climbing, but not necessarily hindlimb reversal. Among hindlimb reversers, the majority exhibit one belly of m. sartorius, the presence of m. extensor digiti I longus, and a fibular origin for m. fibularis longus. These characteristics indicate an emphasis on hip extension, ankle plantarflexion, and pes inversion. However, these characteristics are more likely due to phylogeny than hindlimb reversal because of their presence in closely-related non-reversers. Additional data on families outside of Carnivora may help determine if these myological traits are indeed due to phylogeny. Other myological data, such as moment arms and cross sectional areas, may provide evidence of adaptations for hindlimb reversal.
ContributorsLiu, Margaret Chuan (Author) / Fisher, Rebecca (Thesis director) / Hinrichs, Richard (Committee member) / Kusumi, Kenro (Committee member) / Barrett, The Honors College (Contributor) / School of Life Sciences (Contributor)
Created2014-05
Description
Anole lizards that inhabit the islands and mainland of the Caribbean basin have evolved morphological traits adapted to the microhabitat that they occupy. The anoles on these islands have been characterized as "ecomorphs" or morphologically and behaviorally-adapted groups, including: crown-giant, trunk-crown, trunk, grass-bush, twig, and trunk-ground. Ecomorphs display morphological features that are specifically adapted to the habitat that the anole occupies. One key morphological difference is tail length. While the anoles Anolis carolinensis and A. sagrei have similar ratios of tail length versus snout-to-vent length (SVL), they occupy different microhabitats. Specifically, A. carolinensis inhabits trunk-crown habitats while A. sagrei is found in trunk-ground regions. In this study, I focused on analysis of the caudal vertebrae of these two species, to determine if the structure of the osteological elements reflected differences in microhabitat adaptation. Skeletal preparations reveal that A. carolinensis have 40 \u2014 46 caudal vertebrae, and A. sagrei have 38 \u2014 49 caudal vertebrae. Transverse processes are present in Ca1-8 in A. carolinensis whereas transverse processes in A. sagrei span from Ca1-42 vertebrae. Ca6\u201440 have autotomy planes in A. sagrei, whereas only Ca8\u201417 have autotomy planes in A. carolinensis. These findings indicate that A. carolinensis are limited in the ability to autotomize their tail compared to A. sagrei. A. carolinensis, living higher in the trees than A. sagrei, might incur a greater impairment of locomotor function if autotomized. There appears to be no differences between males and females of both species in respect to vertebrae lengths. Differences between A. carolinensis and A. sagrei in terms of vertebral length are found in Ca12-15, 29-30, 34, and 37. The finding indicates that almost all caudal vertebrae between A. carolinensis and A. sagrei have similar relative lengths, but seven vertebrae have statistically significant differences. The biological significance of the findings is not clear, but functional and myological studies may help elucidate the reason of the observed differences.
ContributorsLasku, Eris (Author) / Kusumi, Kenro (Thesis director) / Fisher, Rebecca (Committee member) / Hsieh, Tonia (Committee member) / Barrett, The Honors College (Contributor) / Department of Chemistry and Biochemistry (Contributor) / School of Life Sciences (Contributor)
Created2013-05
Description
This thesis presents an approach to design and implementation of an adaptive boundary coverage control strategy for a swarm robotic system. Several fields of study are relevant to this project, including; dynamic modeling, control theory, programming, and robotic design. Tools and techniques from these fields were used to design and implement a model simulation and an experimental testbed. To achieve this goal, a simulation of the boundary coverage control strategy was first developed. This simulated model allowed for concept verification for different robot groups and boundary designs. The simulation consisted of a single, constantly expanding circular boundary with a modeled swarm of robots that autonomously allocate themselves around the boundary. Ultimately, this simulation was implemented in an experimental testbed consisting of mobile robots and a moving boundary wall to exhibit the behaviors of the simulated robots. The conclusions from this experiment are hoped to help make further advancements to swarm robotic technology. The results presented show promise for future progress in adaptive control strategies for robotic swarms.
ContributorsMurphy, Hunter Nicholas (Author) / Berman, Spring (Thesis director) / Marvi, Hamid (Committee member) / Mechanical and Aerospace Engineering Program (Contributor) / Barrett, The Honors College (Contributor)
Created2017-05
Description
Anthropomorphic animal characters are common in animation, but there is limited data on the factors that contribute to such a trend. I studied how animated animals in popular movies look and behave like humans, and what that indicates about us that we prefer them that way. My study was conducted via literature review, film review, facial measurements, and the creation of my own character. I discovered the physical importance of eyes in proportion to the rest of the face and the emotional importance of those animals acting as metaphors for us as humans.
ContributorsEhuan, Ariana Jade (Author) / Adamson, Joni (Thesis director) / Drum, Meredith (Committee member) / Fisher, Rebecca (Committee member) / School of Life Sciences (Contributor) / School of Art (Contributor) / Barrett, The Honors College (Contributor)
Created2016-12
Description
Vertebral osteology varies greatly among snake species. This variation may be related to specialization in microhabitat and prey-capture. Radiographs of eight preserved male specimens were taken in order to analyze the vertebral length and morphology of snakes which exhibit extreme characteristics in microhabitat utilization and prey-capture methods (highly arboreal, effective constrictor). This group includes two representatives each from four major families within Serpentes: Boidae, Pythonidae, Viperidae, and Colubridae. The four boids and pythons are effective constrictors, while the four vipers and colubrids are non-constricting. One specimen of each pair is highly arboreal, while the other is terrestrial. Findings support previous research in that constrictors had larger total numbers of vertebrae than non-constrictors. When average maximum adult length and morphology of axial musculature was taken into consideration, however, flexibility gained by vertebral number alone does not theoretically confer a mechanical advantage during constriction, at least among the specimens examined. All arboreal specimens had tails with a greater number of vertebrae than their con-familial terrestrial counterpart, implicating greater flexibility in the caudal region as an important characteristic for arboreality across taxa. Examination of segments of 10 vertebrae revealed that the greatest vertebral elongation occurred at the midpoint of the thoracic region. Reduction in size and length of tail vertebrae appears to occur independently of thoracic vertebrae. Colubrids, specifically, demonstrated a unique caudal vertebral elongation pattern which could potentially be advantageous for quick locomotion. These results indicate that caudal morphology may be more important in behavioral specialization than previously thought.
ContributorsGuerrero, Anna Clemencia (Author) / Fisher, Rebecca (Thesis director) / DeNardo, Dale (Committee member) / Elliott, Steve (Committee member) / School of Life Sciences (Contributor) / Barrett, The Honors College (Contributor)
Created2016-12