The objective of this thesis is to develop design approaches and models for prosthetic ankle joints using kinematic models of the human ankle and compliant mechanisms technology. Compliant mechanisms offer several potential design advantages over traditional rigid-body designs including high reliability and low cost. These design advantages are ideal for use in prosthetics. Some prosthetic ankle/foot systems currently on the market have multiple degrees of freedom yet are expensive. Additionally, even though these systems have multiple degrees of freedom, none of them are designed after the actual movements of the biological ankle. In this thesis a two, single degree-of-freedom hinge joint model, which is a kinematic model based on the biological ankle during walking, is used to develop compliant prosthetic ankle joints. The use of the model together with compliant mechanisms may provide the ability to develop highly functional prosthetic ankle joints at a lower cost than current high-performance prosthetic systems. Finally, a design approach for ankles may facilitate future development for knees, hips or other biological joints.

Variation analysis, or tolerance analysis as it is sometimes called, is typically used to predict variation in critical dimensions in assemblies by calculating the stack-up of the contributing component variations. It is routinely used in manufacturing and assembly environments with great success. Design engineers are able to account for the small changes in dimensions that naturally occur in manufacturing processes, in equipment, and due to operators and still ensure that the assemblies will meet the design specifications and required assembly performance parameters. Furthermore, geometric variation not only affects critical fits and clearances in static assemblies, it can also cause variation in the motion of mechanisms, and their dynamic performance. The fact that variation and motion analysis are both dependent upon the geometry of the assembly makes this area of study much more challenging. This research began while investigating a particular application of dynamic assemblies - automobiles. Suspension and steering systems are prime examples dynamic assemblies. They are also critical systems, for which small changes in dimension can cause dramatic changes in the vehicle performance and capabilities. The goals of this research were to develop the tools necessary to apply the principles of static variation analysis to the kinematic motions of mechanisms. Through these tools, suspension and steering systems could be analyzed over a range of positions to determine how small changes in dimensions could affect the performance of those systems. There are two distinct applications for this research, steering systems and suspension systems. They are treated separately, as they have distinct requirements. Steering systems are mechanisms, for which position information is most critical to performance. In suspension systems, however, the higher order kinematic terms of velocity and acceleration often are more important than position parameters.

The purpose of this study was to examine the correlation between acoustic and kinematic measures of diphthong production in 11 individuals with multiple sclerosis (MS) and 11 neurologically healthy control speakers. The participants produced four diphthongs: /ɔɪ/, /aʊ/, /aɪ/, /eɪ/. These sounds were spoken in a sentence context. Their speech audio signal was recorded with a microphone and their tongue movements were recorded with a magnetic tracking system. The first and second formants (F1 and F2) were computed with acoustic analysis software, and these signals were time-aligned with the vertical and anteroposterior magnet movement records. Pearson correlations between F1 and the magnet's vertical movement and between F2 and anteroposterior movement were computed for the individual diphthongs. The results of this study revealed an often non-linear relationship between the acoustic and kinematic measures. The degree to which the formant measures predicted the lingual movements varied across speakers and also during the on-glide, transition, and off-glide phases of the diphthongs. The findings of this study suggest that the relationship between formants and tongue movements is more complex than would be predicted from the theoretical origins of F1 and F2. Thus, researchers should be aware that acoustic parameters might not always accurately reflect the physical movements of articulators.

ABSTRACT Skier’s Edge: Biomechanical Analysis Benjamin T. Johannes The Skier’s Edge trainer can be used by novice or expert skiers. Testing was performed to analyze if the use of the Skier’s Edge could reduce in shear forces of the valgus moment on the knee joint and anterior cruciate ligament (ACL) due to lesser fatigue of muscle and a higher hamstring to quadricep (H/Q) ratio activity. This leads to a reduction of improper form and an increase in balance. Experiments performed observed the change in muscle activity with the use of the Skier’s Edge over time when compared to other forms of workout (elliptical and or a traditional ski conditioning workout). Comparison of the three workout methods was completed by collecting kinematic, kinetic and electromyographic (EMG) data. Each participant, 9 male skiers (22±3 years old, 70.56±3.44 inches, 206±54 lbs.) and 6 female skiers (22±4 years old, 66.25±3.25 inches, 148±72 lbs.), were separated into even groups between the workout types. Data was collected initially and after a four-week period of exercise for each respective workout group. A relative valgus moment was found with the force and valgus angle data and an H/Q ratio was created using the vastus medialis and semitendinosus EMG data for the respective muscles. The findings of this study show that there were no significant differences between the workout types for either reduction of valgus moment or an increase in H/Q ratio which are indicators of reduced ACL injury. Trends in the data indicate that the elliptical workout may have a positive impact on H/Q when compared to the Skier’s Edge workout. Recommendation for future study includes having participants complete a more intense and longer workout period or to focus on the elliptical and Skier’s Edge workout to test for significant differences to aid in ACL injury reduction.

The primary goal of human locomotion is to translate the body from point A to point B, but humans must have the variability and stability to adapt and recover from constraints they may encounter. The overarching aim of this dissertation was to investigate how constraints arising from external factors (i.e., military load carriage and speed) and internal factors (i.e., hip pain) affect kinematic variability and local dynamic stability of gait. In study 1, I focus on using traditional biomechanical measures to investigate if females and males use different gait mechanics when carrying military-relevant loads, as females and males are known to use different mechanics when walking with no load. In this study, I found that females and males do use different gait mechanics when walking with military-relevant loads. Females make kinematic adaptations at the ankle and knee while males make kinematic adaptations at the hip. The differences in adaptations between females and males may be related to females’ greater risk of injury when carrying load. In study 2, I used the same cohort to investigate how military-relevant loads affect the kinematic variability and local dynamic stability of gait. I found that kinematic variability and local dynamic stability were similarly affected by load. Participants had greater kinematic variability and decreased local dynamic stability when carrying loads, which may indicate an increased risk of falling while carrying load. I also found that local dynamic stability increased with increased walking speed at all loads in the mediolateral and anteroposterior directions. However, decreased stability was detected in the vertical direction, which may require increased energy expenditure. The results of this study indicate that walking faster with increased loads may be more stable, but less energy efficient. In study 3, I investigated the how kinematic variability and local dynamic stability were affected in individuals with hip pain and a history of developmental dysplasia. I found that kinematic variability and local dynamic stability were not similarly affected in these individuals. I found that kinematic variability was greater in individuals with hip pain compared to healthy controls, but there was no difference in local dynamic stability between groups. The overall finding of this dissertation is that the relationship between kinematic variability and local dynamic stability may be dependent on the factor investigated. / 2020-07-06T00:00:00Z

A multi-unit tracked vehicle such as a continuous haulage system is widely used in underground mining applications due to its high mobility and payload capacity on rugged and soft terrain. To automate such a system, a high fidelity model of a tracked vehicle is essential in designing a controller for each tracked vehicle in the system, and a system model is required to simulate its response to input commands. This thesis presents the 2-D mathematical models of a tracked vehicle and a multi-unit tracked vehicle. All existing track-terrain interaction models are investigated and modified. By employing the modified track-terrain interaction model and applying Newton's second law of motion, the equations of motion of both single and multi-unit tracked vehicles can be derived. Computer programs for simulating the motions of these tracked vehicles on level ground have been implemented on a digital computer based on the derived system of differential equations. The fourth-order Runge-Kutta and Keun's methods are adopted to numerically integrate these differential equations. The simulation results clearly show that the programs can accurately predict the motion of a tracked vehicle maneuvered on horizontal plane, and closely predict the response of a multi-unit tracked vehicle operated on level ground its command inputs. / Master of Science

Abstract not provided. / Thesis / Master of Engineering (ME)

Kinematic simulation (KS) is a means of generating a turbulent-like velocity field, in a manner that enforces an input Eulerian energy spectrum. Such models have also been applied in particle-laden flows, due to their ability to enforce spatial organization of the fluid velocity field when simulating the trajectories of individual particles. A critical evaluation of KS is presented; in particular, its ability to reproduce single-particle Lagrangian statistics is examined. Also the ability of KS to reproduce the preferential concentration of inertial particles is explored. Some numerical results are presented, in which fluid tracers and inertial particles are transported alternatively by (1) simulated turbulence generated by direct numerical simulation (DNS) of the incompressible Navier-Stokes equations, and (2) KS. The effect of unsteadiness formulation in particular is examined. It is found that even steady KS qualitatively reproduces the continuity effect, clustering of inertial particles, elevated dispersion of inertial particles and the intermittent turbulence velocity signal. A novel method is then motivated and formulated, in which, for input RANS parameters, a simulated spectrum is used to generate a KS field which enforces a target Lagrangian timescale. This method is then tested against an existing experimental benchmark, and good agreement is obtained. / Thesis / Doctor of Philosophy (PhD) / Turbulence arises in an immense variety of industrial and scientific applications; from weather to automotive design; from medicine to nuclear engineering. Because turbulence is chaotic, it is difficult to make accurate predictions of how a turbulent flow will behave in a given scenario. The objective of my research is to find easier ways of accurately modelling turbulence in a certain class of particle-laden flows.

Nowadays, more and more flexible and efficient processes are required in modern industrial applications. In this field, robots are a key technoligy. In this paper a application is considered, where a 6-axis-industrial robot has to pick-and-place objects time efficiently in a constantly changing environment. Therefore, a concept for automated motion planning is presented, which is composed of two steps which are path planning and trajectory generation. In this paper suitable and established model-based methods are analyzed and chosen. Eventually, the suitability of the presented concept for the considered task is shown by implementing the concept in Matlab and applying it to a 6-axis articulated robot arm.

The popularity of running barefoot or in minimalist shoes has notably increased in the last decade due to claims of injury prevention, enhanced running efficiency, and improved performance when compared to running in shoes (shod). A systematic review of the literature was performed using the Downs and Black checklist to assess the methodological quality of studies proposing risks or benefits between running barefoot, shod, or in minimalist shoes. The databases Ovid MEDLINE, SPORTDiscus, and CINAHL were searched using keywords or "Booleans" including: "Barefoot", "Running" and "Minimalist," exclusively. All included articles were obtained from peer reviewed journals in the English language with a link to full text and no limit for year of publication. The final selection was made based on inclusion of at least one of the following outcome variables: pain, injury rate, running economy, joint forces, running velocity, electromyography, muscle performance, or edema. Significant results were gathered from identified articles and compared using "Levels of Evidence" by Furlan et al. Twenty-three publications were identified and rated for quality assessment in September 2013. Out of 27 possible points on the Downs and Black checklist, all articles scored between 13 and 19 points with a mean of 17.4. Evidence from the articles ranged from very limited to moderate. Moderate evidence suggested overall less maximum vertical ground reaction forces, less extension moment and power absorption at the knee, less foot and ankle dorsiflexion at ground contact, less ground contact time, shorter stride length, increased stride frequency (cadence), as well as increased knee flexion at ground contact in barefoot running compared to shod. The low scores from the quality assessment using the Downs and Black checklist indicates that improved methodological quality is necessary to provide strong evidence comparing the risks and benefits of running barefoot, shod, and in minimalist shoes. The literature between shod, minimalist, and barefoot running is inconclusive. There is limited evidence showing differences in kinematics, kinetics, electromyography, and economy results in minimalist shoes. Thus, an alternative and suitable method to effectively replicate barefoot running has not yet been determined.