Analysis and Design of a Feedback Controlled Adaptive Pneumatic Cast

<p>A pneumatic system with PID control for an actively controlled cast is designed. The cast is intended to aid healing of diabetic foot ulcers by relieving pressure from the sole of a patient's foot and distributing it to the calf. This is accomplished by a pneumatic system which maintains set pressure in multiple air bladders. The research began by defining an electrical circuit analogous to a single supply subsystem. Tests are performed to determine the coefficients for each component. These coefficients are used in a mathematical model to better understand the response of the system to pressure input. A controller is designed for a single subsystem using Ziegler-Nichols first method as a starting point. PID control is extended to each configuration option. Control theory is used to determine an optimal configuration of the bladder subsystems. Series, parallel, and a hybrid configuration are considered. The cost, complexity, and performance of each configuration is used in a weighted decision matrix to choose the best configuration. The parallel configuration is chosen as the optimal solution. Because the pump used in the design is capable of supplying all air bladders simultaneously, the parallel configuration can be simplified to a single subsystem. The model of the subsystem is validated against physical tests. The controller driving the single supply subsystem is used as a guideline for designing a modified duty cycle controller. This controller is implemented using simple pneumatic and electrical components.</p>

Name thesis:degree_name

M.S.

Level thesis:degree_level

Masters Thesis

Year dc:date.available

2010

Author dc:creator

• Mueller, Susan Renee

Contributors dc:contributor

• Rahmat Shoureshi, Ph.D.
• Yun-Bo Yi
• Matthew Rutherford
• Stephen Albert

• Active
• Biomedical
• Control
• Diabetic ulcers
• Feedback
• Mechatronics
• Electrical and Computer Engineering

Statement dc:rights

• <p>Copyright is held by the author. User is responsible for all copyright compliance.</p>

Language dc:language

en

Repository record dc:identifier

https://digitalcommons.du.edu/etd/886

OAI identifier oai:identifier

oai:digitalcommons.du.edu:etd-1885