A S S I S T R E K Michael Elpers Kyle Fleege Kevin Mason Mary Phillips Theresa Polowski Megan Schroeder AMBULATORY ASSISTANCE SYSTEM Critical Concept Design Review

Project Objective Design and prototype an ambulatory assistance device for a temporary injury Initial Concepts:

Design Selection Contacted medical professionals to discuss current rehabilitation devices Researched ADA requirements Tested various devices Tested and used crutches Prototyped and used a knee crutch Crutches - Large user energy input - User’s arms and shoulders become sore after extended use - Cheap (under $30) Powered Wheelchairs - Increased Mobility with minimum energy input - Expensive (over $500)

Assistrek Design Objective User age: years old Healthy/strong enough to use crutches Single leg injury Meet ADA requirements i.Width < 32 in. ii.Length < 3 ft iii.Able to complete a 180° turn in 5 ft wide space Motor powered movement Ability to maneuver and turn Inclusion of crutches into design

11/28/06Assistrek Final Concept Selection Key Features Motor powered Incorporates crutches 3 wheeled Back rest for user safety and support

11/28/06Assistrek Final Design

11/28/06Assistrek Final Design

11/28/06Assistrek Design Rationale vs. Advantages to Standing Design: - Easy on/off - Incorporates crutches - Helps maintain muscle of healthy leg - Assists recovery

Technical Issues Issues Identified: Platform material and thickness Motor type and size Steering angle and radius Type of crutch locking device Axle diameter and material Back support material and size

Design Decisions ¾ in. HDPE platform Direct Current motor ½ in. steel axle

11/28/06Assistrek Design Decisions 58° rotation of front wheel Spring force sufficient for crutch locks Black steel pipe, minimum 3/8 in. diameter for backrest

Issues Resolved Front steering system Issue: Front wheel too wide for intended steering fork Result: Chose a four bar mechanism and castor wheel

11/28/06Assistrek Issues Resolved Powering rear wheels Issue: Both rear wheels powered inhibits turning Result: Powered one rear wheel and allowed other to spin freely Free Spinning Wheel

11/28/06Assistrek Issues Resolved Rear axle deflection Issue: Rear axle diameter too small for torque applied by motor Result: Replaced deformed axle and installed bushings to support axle

11/28/06Assistrek Feasibility of Design Forward and reverse settings

Feasibility of Design User can get on or off product in under 45 seconds

11/28/06Assistrek Feasibility of Design Able to complete a 180° turn within a 5 ft radius Video

11/28/06Assistrek Feasibility of Design Budget:

11/28/06Assistrek Feasibility of Design Total weight less than 150 lbs ~ 100 lbs 3 wheels on ground at all times Crutches maintain position within 10° from vertical Backrest deflection less than 5 in. under user weight

11/28/06Assistrek Future Modifications CRUTCH LOCKING DEVICE Improve material Automate Recess into board Weatherproof design Redistribute weight on platform POWER SYSTEM Optimize power output and size Introduce variable speed control LCD user interface Brakes

Assistrek Acknowledgements -Mr. Greg Brownell -Mr. Leon Hluchota -AME40463 TA’s Thank you to: - Mr. Jim Russ, Notre Dame Head Football Trainer - Mr. Ricardo Moreno, St. Mary’s High School Athletic Director - Dr. Scott Kreiner, MD, Fellowship Director at Ahwatukee Sports and Spine - Mr. Stacey Whiteside, Manager at Tempe CDC -Dr. Stephen Batill -Dr. John Renaud -Dr. Michael Stanisic

Questions