Defense Presentation
Announcement
Hey everyone, I successfully completed my PhD where my research focused on the Development and Application of Semi-Active Prostheses. As I embark on the next chapter of my career, I am actively seeking opportunities in engineering, specifically within the fields of biomechanics, robotics, mechatronics, and embedded systems. If you're curious about my research or happen to know of any opportunities in these fields, please don't hesitate to get in touch. Your support and connections mean a lot to me.
Summary of my Dissertation
(Taken directly from the abstract of my dissertation) There is a need for improved design and function of prosthetic devices to aid walking in persons with transtibial amputations. This dissertation focused on two semi-active ankle-foot prosthetic devices, the Variable Stiffness Foot (VSF) and Two Axis aDaptable Ankle (TADA), which allow users to change biomechanical ankle-foot functions using simpler designs, lower costs, and less power than active prostheses. The background for this dissertation explored the main lower-limb biomechanical principles of prosthetic design, prosthetic-walking mechanics, and sensor feedback. The VSF manuscript investigated the mechanical impact of adjusting stiffness on lower limb mechanics using a prosthetic foot, which can modulate forefoot stiffness. A less stiff VSF resulted in increased ankle dorsiflexion angle, decreased ankle plantarflexor moment, decreased knee extension, decreased knee flexor moment, and increased magnitudes of prosthetic energy storage, energy return, and push-off power. These findings suggest that a less stiff VSF may offer advantages in lower joint moments and greater ankle angle range of motion for individuals with lower-limb prostheses. The Two Axis aDaptable Ankle (TADA) is a semi-active prosthetic ankle that offers independent modulation of sagittal and frontal ankle angles. The first TADA study modified a Raspberry Pi 4 for real-time control of brushless direct-current motors, allowing for precise and reliable ankle angle adjustments. The control system employed CANopen over EtherCAT (CoE) for synchronized communication between the Raspberry Pi and motor controllers. The results demonstrated improved movement times, lower movement errors, and higher data transmission rates. As a continuation, the final TADA study aimed to create an ankle prosthesis that can synchronously record lower-body kinematics and kinetics and assess the sensitivity of those mechanics to different walking speeds and ankle angles for an unimpaired participant. Using a pylon load cell, the results showed that peak magnitudes and impulses increased for plantarflexor moments with increased plantarflexion angle and for evertor moments with increased inversion angles. Moreover, the peak sagittal pylon moments increased with higher walking speeds. The integrated control system of the TADA effectively controls ankle angles, can affect lower-body mechanical outcomes, and can allow for efficient adaptation to various speeds and terrains in users with transtibial amputations.
Resources
References
Nichols, Kieran. The University of Wisconsin - Madison ProQuest Dissertations Publishing, 2023. 30637924. (Published document)