Instrumented Walker Project Manager : Jairus Potts Rockwell Shields Christopher Barnett Skyler Bullington Larson Stacy Tommy FrankenBerger
Background -The walker is being developed for the Mayo Clinic in Rochester, MN -The walker will be implemented with load cells and will determine forces in the z-direction that are applied by the patient. -This data will be transmitted from the walker using Arduino and to MotionMonitor. -The data will be analyzed in Motion Monitor and will help with developing improved rehabilitation plans for patients with spinal injuries.
Design Criteria Light weight Removable Accurately determine applied forces Ability to communicate to Motion Monitor for analysis
Work Completed Sensor Selection Load Cell Attachment Prototype Preliminary Testing Power Regulation Circuit Prototype Load Cell signal Amplification preliminary design
Sensors Selection •Load Cells Single axis load cell that will be used to determine the forces in the z-direction being applied to each leg.
Attachment Design - Load cells will be placed in all four feet - An attachment has been designed, and 3D printed currently, the final Aluminum attachment has had a work order placed at the Machine Shop.
Attachment
Power Regulation Circuit Proper Regulation of Excitation Voltage to 10 Vdc Designed for use with Li-ion Battery Redesigned board printed
Board Design Amplification Circuit Designed 24 bit Resolution Low Pass filter selected for post amplification signal Boards printed for component installation
Calibration Testing -The testing method has been redesigned -Using a newer reference board, Eliminates Oscillator -Will help to shorten the timetable for calibration of all 4 load cells -Goal is to develop 4 separate input formulae
Sample Calibration
Testing/Analysis Currently establishing a bench testing station for load cell calibration Testing apparatus designed and 3D printed for weight testing Detailed Calibration method and procedure Initial testing has commenced Individual load cell testing will begin this week Determined: Load cell output signal voltage ranges and behavior Signal Output frequency characteristics Initial Amplification Board added excessive noise
Programming & Motion Monitor Data will be analyzed using motion monitor The Voltage output received will be used to determine the corresponding forces on the walker Formulae will be provided to convert voltage into applied force Applied forces combined into total applied weight
Crutch Design - Crutches will be implemented with the load cells at the feet - Attachment design will be modified: Lengthened and thickened to accommodate the greater forces at each leg. - Data will be collected and analyzed in Motion Monitor, same as the walker. - Same micro controller configuration
Upcoming Tasks Completion of Load cell Calibration Power Supply Board re-design phase Complete initial crutch design - Motion monitor integration
Gantt Chart