Logan Ranger Energy Management System for a Prosthetic Limb: Work Day 11.21.18

Work Day-Student came in on a day off school
Date:11.21.18
Time: 4:30-7:00
Location: Logan HS
Students: Caitlin, Avery, Paige, Alex, Thaying, Thomas

We took two steps forward and one back. The software side of the project
showed some promise with Austin successfully using an Arduino Uno and
Bluetooth module to interface with his phone to turn on and off an LED. Next
step will be to change the interface on the phone to show additional inputs.

Avery and Caitlin work on the Kiva software with limited success. We have a
hardware issue where the software does not want to run on our laptops. We
decided to see if Kiva is a viable option by the end of next week. Python
does run on it. We also have to work on our energy budget for the software
end.

Alex and Thomas worked on the locating the “hip joint” hole where a ½” hole
will be drilled in our tester for that pivot point. Calculations will have
to be redone for the motor location. Once that is done, we can begin to
mount and wire the motor.

Paige is making progress on the presentation and social media. She is ready
to go live with the accounts and keeping them updated will be a challenge.

Thiyang put up our first blog post and will have the second by the end of
next week.

The ordering process for tax exempt can be a pain. The same vendor
(Grainger) charged tax twice on our tax exempt account. The first one took
1.5 hours to resolve. The second time they said all states are tax exempt
except Wisconsin (which is not true) and cannot be resolved until Monday, Nov. 26th.

Other things we looked at:

Prosthetic Test System Alternatives
Basis for Force Generation
Direct mechanical thrust
Direct Weight
High mechanical advantage(scissors jack, etc.)
Discussed Alternatives; progress with conversion testing, idea conversion
model, electronics

Conclusions:
With reasonable equipment, direct energy recovery mechanisms can be tested
With high mechanical advantage fixtures, with limited movement, full force
testing can be achieved. To achieve higher forces, knee joint must be used
in "scissors jack" configuration. Ref:
https://www.engineersedge.com/mechanics_machines/scissor-lift.htm

A variety of test conditions can be created with controlled, limited equipment

Prosthetic Test System Alternatives
Use of Gearmotor and mechanical linkages to control movement and test area
forces
Nominal speed: 1 cycle per second
Forces applied to test area: 20-50 lbs est.

Configuration 1: Direct "Scissors jack" application to maximize force with
minimal UUT travel
Configuration 2: Nominal force for testing energy features, foot rolling to
exercise different conversion modes using simulated artificial foot carrier
Configuration 3: Larger force capability for testing with combined
application samples including current sample of carbon fiber foot element
Configuration 4: Variable speed application to illustrate special cases
application (running?) Possible use of direct drive motor

Scissors Jack sequences:
Lifted leg element has no contact with floor
Initial contact of foot to floor is made, knee joint is bent reducing floor
thrust movement by 0.5 inch
Force is applied to knee joint to create foot thrust force, foot movement is
up to 0.5 inch OR foot element bending takes place
Full foot thrust force is developed
Conclusion: fixture must be adjustable in thrust distance and thrust attack
angle to develop forces required in the foot element under test(suggestion-
use human model in simulation poses) Restricting rollers can be used with
test samples in fixtures!

Austin working on the App that will monitor our device. Notice the LED is turning on and off through a Bluetooth connection he programmed.