Concept Elimination and Comparison

After the brain storm, we seperated our ideas into the following catagories:

Single Piece 

Mechanical Moving Arms

Tree Mount

Electrical Moving Arms

Then we ruled out the categories that we knew wouldn't fit our criteria. The electrical moving arms category was eliminated due to its use of  power; we want as little power being used as possible so the battery doesn't drain down.  
The single piece category was eliminated because it wouldn't allow for easy access to change out wires or sensors that might be damaged.  We need something that would be easy to fix on the mountain.  

So that left the mechanical moving arms and tree mount systems.  From there, we picked the most realistic choices from the list using our design goals and made a Pugh chart.  Initially, the Speed Rail design was chosen but then was found to be too expensive.  So in the redesign, the T stand with modifications to the anchoring system, was chosen.  Simulations showed that this design would withstand the mountain environment.  Below are photos from the simulations (click on the simulations to view the simulation video):

Contours of Displacement

Countours of Stress

Another design chalenge of the SnowMAN was to select a battery technology that would fit the constraints of the  environment.  We made a Pugh Chart to help us compare the battery technologies to make a descision.  We ruled out the SLA because they don't operate at the appropriate temperatures and it's I-V characteristics aren't as flat as the NiCd and A123 Systems.  Li Ion batteries were ruled out due to the fact that they do not operate at freezing temperatures.  The A123 were chosen over the NiCd because they recharge faster and have a higher capacity rating.  
We made a  House of Quality to help find problems with the overall design.  

 

Katie Gallo          kgallo@uvm.edu
Tom Lanagan     tlanagan@uvm.edu