Final Post - Don

Hello everyone,

It has been a great summer. There is no doubt about that. Here is a summary of everything I have been working on this summer.

Gas-Power-Cycle-Specific Pulley Optimization for a Walking-Engine-Actuated Active Ankle-Foot Orthosis

Donald H. Kuettel III MSOE REU 2014

Outcome

The main goal of this research was to help people with disabilities regain natural walking ability by replicating the normal walking gait of a human through the use of a walking-engine-actuated active ankle-foot orthosis (AAFO). This was done using an internal-combustion engine and pulley system to reproduce the moment experienced at the ankle during gait. Through this research, the optimal pulley geometry was determined for the AAFO, but had a very complicated geometry.

Impact/Benefit

Active orthotic devices for joint articulation have a vast number of applications that could benefit many people. Individual examples of this include: joint articulation for people suffering from disabilities, increased load carrying capacity and walking distance for humans, and gait training applications. The results of this research provided insight and laid the groundwork for future experiments for the further development of un-tethered, compact, lightweight, efficient, long-lasting, and safe AAFO devices.

Explanation

This research investigated the optimization of a pulley system for the primary actuator of an AAFO utilizing a high-efficiency pneumatic “Walking Engine”. The AAFO’s internal-combustion (IC) engine was characterized using a dual-combustion (limited-pressure) gas-power-cycle model. Using the dual-combustion model, both a pressure-volume diagram and the thermodynamic engine efficiency were calculated. The moment experienced at the ankle due to the AAFO was calculated using the pressures in the AAFO engine. By finding the pressure in the AAFO engine as a function of time and multiplying it by the cross-sectional area of the actuator piston, the force output of the engine was then determined. Finally, by dividing the optimal ankle moment by the engine’s force output, the optimal pulley geometry was found as a function of time.

Meeting everybody involved in the REU Program has been a great honor. I will give the whole parting words thing a shot. In my opinion one of the most important aspects of research is to share the knowledge that you have gained. It is only through this process of sharing that the world as a whole may benefit from the research that has been done. So get out here and don't be afraid to tell people about the great accomplishments that you have made.

This is Donald Harry Kuettel III signing off.