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- Creators: Barrett, The Honors College
- Creators: Sugar, Thomas
- Resource Type: Text
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
As life expectancy continually rises, many age-related conditions such as deteriorated gait and decreased stability begin to play a larger role in affecting the quality of life for all individuals. Medical expenses associated with falls in the elderly population surpassed $50 Billion in 2015 alone. Understanding fall risk and developing robust metrics and methods of assessment has become more important than ever. While traditional fall risk has looked at classical gait parameters, dynamic stability has gained traction as a more accurate representation of stability during active movement and daily activities. This project seeks to determine the effects on the internal perturbation of gait velocity on dynamic stability represented by the Maximal Lyapunov Exponent (MLE) of multiple acceleration vectors, as well as the efficacy of varying methodology used to assess dynamic stability. Data from 15 healthy, college aged individuals was collected. Significant differences were shown between certain gait velocity trials for one analysis of the three methods explored, while overall trends suggested potential differences between gait velocities with other methodologies warranting further investigation.
ContributorsKreisler, Itai Goeta (Author) / Lockhart, Thurmon (Thesis director) / Rezvanian, Saba (Committee member) / W.P. Carey School of Business (Contributor) / Harrington Bioengineering Program (Contributor) / Barrett, The Honors College (Contributor)
Created2018-05
Description
Many industries require workers in warehouse and stockroom environments to perform frequent lifting tasks. Over time these repeated tasks can lead to excess strain on the worker's body and reduced productivity. This project seeks to develop an exoskeletal wrist fixture to be used in conjunction with a powered exoskeleton arm to aid workers performing box lifting types of tasks. Existing products aimed at improving worker comfort and productivity typically employ either fully powered exoskeleton suits or utilize minimally powered spring arms and/or fixtures. These designs either reduce stress to the user's body through powered arms and grippers operated via handheld controls which have limited functionality, or they use a more minimal setup that reduces some load, but exposes the user's hands and wrists to injury by directing support to the forearm. The design proposed here seeks to strike a balance between size, weight, and power requirements and also proposes a novel wrist exoskeleton design which minimizes stress on the user's wrists by directly interfacing with the object to be picked up. The design of the wrist exoskeleton was approached through initially selecting degrees of freedom and a ROM (range of motion) to accommodate. Feel and functionality were improved through an iterative prototyping process which yielded two primary designs. A novel "clip-in" method was proposed to allow the user to easily attach and detach from the exoskeleton. Designs utilized a contact surface intended to be used with dry fibrillary adhesives to maximize exoskeleton grip. Two final designs, which used two pivots in opposite kinematic order, were constructed and tested to determine the best kinematic layout. The best design had two prototypes created to be worn with passive test arms that attached to the user though a specially designed belt.
ContributorsGreason, Kenneth Berend (Author) / Sugar, Thomas (Thesis director) / Holgate, Matthew (Committee member) / Mechanical and Aerospace Engineering Program (Contributor) / Barrett, The Honors College (Contributor)
Created2016-12
Description
For the past two decades, advanced Limb Gait Simulators and Exoskeletons have been developed to improve walking rehabilitation. A Limb Gait Simulator is used to analyze the human step cycle and/or assist a user walking on a treadmill. Most modern limb gait simulators, such as ALEX, have proven themselves effective and reliable through their usage of motors, springs, cables, elastics, pneumatics and reaction loads. These mechanisms apply internal forces and reaction loads to the body. On the other hand, external forces are those caused by an external agent outside the system such as air, water, or magnets. A design for an exoskeleton using external forces has seldom been attempted by researchers. This thesis project focuses on the development of a Limb Gait Simulator based on a Pure External Force and has proven its effectiveness in generating torque on the human leg. The external force is generated through air propulsion using an Electric Ducted Fan (EDF) motor. Such a motor is typically used for remote control airplanes, but their applications can go beyond this. The objective of this research is to generate torque on the human leg through the control of the EDF engines thrust and the opening/closing of the reverse thruster flaps. This device qualifies as "assist as needed"; the user is entirely in control of how much assistance he or she may want. Static thrust values for the EDF engine are recorded using a thrust test stand. The product of the thrust (N) and the distance on the thigh (m) is the resulting torque. With the motor running at maximum RPM, the highest torque value reached was that of 3.93 (Nm). The motor EDF motor is powered by a 6S 5000 mAh LiPo battery. This torque value could be increased with the usage of a second battery connected in series, but this comes at a price. The designed limb gait simulator demonstrates that external forces, such as air, could have potential in the development of future rehabilitation devices.
ContributorsToulouse, Tanguy Nathan (Author) / Sugar, Thomas (Thesis director) / Artemiadis, Panagiotis (Committee member) / Mechanical and Aerospace Engineering Program (Contributor) / Barrett, The Honors College (Contributor)
Created2016-12
Description
Gait training therapies are methods for improving the walking stability of individuals who have difficulty walking, whether it is due to injury or neuromuscular conditions. Perturbation training that causes individuals to correct their balance and actively improve their stability could potentially lead to longer term benefits for those with unstable gait. Subjects had the medial lateral movement of their center of mass measured through motion-tracking software (D-Flow 3 and Vicon Nexus 2.2). Perturbation training completed with the GRAIL treadmill randomly triggered medial-lateral sway perturbations of 3 cm a total of fifteen times throughout a five minute training period. Data collected to compare baseline, post-training, and one week follow-up dynamic stabilities were recorded over three minutes without any perturbations. There were no statistically significant differences when comparing the results of all subjects at each instance of data collection with each other. Thus, the perturbation training had no significant impact on the dynamic stability of gait. Major limitations that lend to the inconclusive nature of this study include a small sample size, no repetitions, and only one round of training. Further work can be done to better assess the potential impacts of perturbation training on walking stability for therapeutic use.
ContributorsJamali, Neema (Author) / Lockhart, Thurmon (Thesis director) / Soangra, Rahul (Committee member) / School of Biological and Health Systems Engineering (Contributor) / Barrett, The Honors College (Contributor)
Created2017-05
Description
While REM Sleep Behavior disorder (RBD) has been linked with synucleinopathies, difficulties persist in clinically convenient diagnostic tools which can differentiate between underlying diseases. Identifying markers in the gait of RBD patients may ease the diagnostic process and indicate potential or status for developing more severe disorders. Individuals were referred to Movement Disorders Center of Arizona (MDCA) by a sleep specialist with a confirmed diagnosis of RBD, or those who were clinically indicated after questioning. All participants underwent a skin-biopsy test for α-synuclein, I-ioflupane dopamine transporter(DAT) scan, and had their gait velocity, cadence and stride dynamics assessed by an automated gait analysis system.
ContributorsWebster, Samuel (Author) / Peterson, Daniel (Thesis director) / Evidente, Virgilio (Committee member) / Barrett, The Honors College (Contributor) / Department of Physics (Contributor)
Created2023-05
Description
Down syndrome (DS) is caused by either an extra copy of chromosome 21 or by extra material on chromosome 21. This causes various levels of intellectual disability and issues with gross motor skill development which can prevent these individuals from participating in activities of daily living (ADL) such as getting dressed, self-care, or grocery shopping. People with DS have a decreased ability to balance, an abnormal and slower gait pattern, difficulty adapting to new environments, and a lack of improvement in these areas with growth and development when compared to their neurotypical peers. The objective of this study was to determine the immediate effects of resistance training (RT) and assisted cycle therapy (ACT) on adults with DS’s balance ability and gait speed. Each participant completed one session of RT, ACT (stationary cycling with the assistance of a motor to maintain a cadence of at least 35% greater than their voluntary cycling speed), and no training in a randomly selected order. Balance and gait speed were measured by a Clinical Test of Sensory Interaction on Balance (CTSIB) (i.e., eyes open firm surface, eyes closed firm surface, eyes open foam surface, eyes closed foam surface) on a Balance Tracking System Board (Btracks board) and by a Timed Up and Go (TUG) test. A total of ten participants’ data was used for analysis. The measures of total path length (cm), anterior-posterior (AP) excursion, and medial-lateral (ML) excursion were used to analyze the CTSIB. The average time was used to analyze the TUG test. The results showed that the eyes closed foam surface balance task was the most challenging balance task for every participant in every intervention. Furthermore, the most improvement was evident in the eyes closed foam surface balance task from pre to post intervention in all of the interventions. Post hoc tests also indicated statistically significant improvements of path length from pre to post in the RT intervention with the eyes closed foam surface balance task as well as with AP excursion in the ACT intervention with the eyes closed foam surface balance task. Possible explanations for improvements from pre to post in the eyes closed foam balance task across all interventions will be discussed with respect to the length of the intervention, and the effect of strength, social and learned factors on balance in adults with DS.
ContributorsKeim, Jeannette Danielle (Author) / Ringenbach, Shannon (Thesis director) / Peterson, Daniel (Committee member) / College of Health Solutions (Contributor) / Barrett, The Honors College (Contributor)
Created2020-12
Description
This research seeks to present the design and testing of exoskeletons capable of assisting with walking gait, squatting, and fall prevention activities. The dissertation introduces wearable
robotics and exoskeletons and then progresses into specific applications and developments in the
targeted field. Following the introduction, chapters present and discuss different wearable
exoskeletons built to address known issues with workers and individuals with increased risk of fall.
The presentation is concluded by an overall analysis of the resulting developments and identifying
future work in the field.
ContributorsOlson, Jason Stewart (Author) / Redkar, Sangram (Thesis advisor) / Sugar, Thomas (Committee member) / Honeycutt, Claire (Committee member) / Arizona State University (Publisher)
Created2021
Description
The mean age of the world’s population is rapidly increasing and with that growth in an aging population a large number of elderly people are in need of walking assistance. In addition, a number of medical conditions contribute to gait disorders that require gait rehabilitation. Wearable robotics can be used to improve functional outcomes in the gait rehabilitation process. The ankle push-off phase of an individual’s gait is vital to their ability to walk and propel themselves forward. During the ankle push-off phase of walking, plantar flexors are required to providing a large amount of force to power the heel off the ground.
The purpose of this project is to improve upon the passive ankle foot orthosis originally designed in the ASU’s Robotics and Intelligent Systems Laboratory (RISE Lab). This device utilizes springs positioned parallel to the user’s Achilles tendon which store energy to be released during the push off phase of the user’s gait cycle. Goals of the project are to improve the speed and reliability of the ratchet and pawl mechanism, design the device to fit a wider range of shoe sizes, and reduce the overall mass and size of the device. The resulting system is semi-passive and only utilizes a single solenoid to unlock the ratcheting mechanism when the spring’s potential force is required. The device created also utilizes constant force springs rather than traditional linear springs which allows for a more predictable level of force. A healthy user tested the device on a treadmill and surface electromyography (sEMG) sensors were placed on the user’s plantar flexor muscles to monitor potential reductions in muscular activity resulting from the assistance provided by the AFO device. The data demonstrates the robotic shoe was able to assist during the heel-off stage and reduced activation in the plantar flexor muscles was evident from the EMG data collected. As this is an ongoing research project, this thesis will also recommend possible design upgrades and changes to be made to the device in the future. These upgrades include utilizing a carbon fiber or lightweight plastic frame such as many of the traditional ankle foot-orthosis sold today and introducing a system to regulate the amount of spring force applied as a function of the force required at specific times of the heel off gait phase.
The purpose of this project is to improve upon the passive ankle foot orthosis originally designed in the ASU’s Robotics and Intelligent Systems Laboratory (RISE Lab). This device utilizes springs positioned parallel to the user’s Achilles tendon which store energy to be released during the push off phase of the user’s gait cycle. Goals of the project are to improve the speed and reliability of the ratchet and pawl mechanism, design the device to fit a wider range of shoe sizes, and reduce the overall mass and size of the device. The resulting system is semi-passive and only utilizes a single solenoid to unlock the ratcheting mechanism when the spring’s potential force is required. The device created also utilizes constant force springs rather than traditional linear springs which allows for a more predictable level of force. A healthy user tested the device on a treadmill and surface electromyography (sEMG) sensors were placed on the user’s plantar flexor muscles to monitor potential reductions in muscular activity resulting from the assistance provided by the AFO device. The data demonstrates the robotic shoe was able to assist during the heel-off stage and reduced activation in the plantar flexor muscles was evident from the EMG data collected. As this is an ongoing research project, this thesis will also recommend possible design upgrades and changes to be made to the device in the future. These upgrades include utilizing a carbon fiber or lightweight plastic frame such as many of the traditional ankle foot-orthosis sold today and introducing a system to regulate the amount of spring force applied as a function of the force required at specific times of the heel off gait phase.
ContributorsSchaller, Marcus Frank (Author) / Zhang, Wenlong (Thesis director) / Sugar, Thomas (Committee member) / Engineering Programs (Contributor) / Barrett, The Honors College (Contributor)
Created2019-12
Description
Human walking is a complex and rhythmical activity that comprises of the brain, nerves and muscles. Neuromuscular disorder (NMD) is a broad term that refers to conditions that affect the proper use of muscles and nervous system, thus also impairing the walking or gait cycle of an individual. The improper gait cycle might be attributed to the lack of force produced at the toe-off stage. This project addresses if it is possible to create an OpenSim model to find the ideal time and force magnitude needed of an assistive force ankle device to improve gait patterns in individuals with NMD.
ContributorsRivera, Jose Luis (Author) / Zhang, Wenlong (Thesis director) / Lockhart, Thurmon (Committee member) / Harrington Bioengineering Program (Contributor, Contributor) / Barrett, The Honors College (Contributor)
Created2019-05