Group Q

In the design evolution process the team started with five base designs, one that was created for the first few weeks of lab and additionally, one per team member that they drafted in the creative design thinking lab in preliminary PR&D.  These four drawings can be found in the PR&D lab week 4.  In creating this design the team looked to the MCR in order to know which design aspects to keep in mind. Then from there the team used concept scoring and screening to narrow down the best designs to take into Advanced Research and Design testing. In the concept screening matrix shown below the team picked aspects of the AEV that were important to them and related to their MCR in order to get a base idea of which designs were not sufficient.

Success Criteria Reference Design A Design B Design C Design D Design E
Stability 0 + 0 + 0
Efficiency 0 0 0 0 0 0
Amount of Material 0 + + +
Durability 0 + 0 + + +
Safety 0 0 + +
Sum +’s 0 2 1 3 2 3
Sum 0’s 5 2 3 1 2 1
Sum -‘s 0 1 1 1 1 1
Net Score 0 1 0 2 1 2
Continue Combine Yes No Yes Revise Yes

Through the screening process design B was dropped since it got a score of zero which meant it’s advantages did not outweigh it’s disadvantages when compared to the sample AEV. Next in the concept scoring process the categories were weighted in order to give a more holistic analysis. That table is shown below.

Column1 Reference Design A Design C Design D Design E
Success Criteria Weight Rating Weighted Score Rating Weighted Score Rating Weighted Score Rating Weighted Score Rating Weighted Score
Stability 0.3 3 0.9 4 1.2 4 1.2 3 0.9 2 0.6
Efficiency 0.1 2 0.2 2 0.2 2 0.2 2 0.2 2 0.2
Amount of Material 0.15 2 0.3 1 0.15 1 0.15 3 0.45 5 0.75
Durability 0.2 3 0.6 4 0.8 5 1 4 0.8 4 0.8
Safety 0.25 3 0.75 4 1 4 1 2 0.5 4 1
Total Score 2.75 3.35 3.55 2.85 3.35
Continue No No Develop No Develop

Through this process Design C and E were chosen because they had two of the highest scores overall and preformed well in the categories that were most important to the team.

These two designs were further developed in the AR&D process through energy analysis and coasting vs power breaking. In coasting vs power breaking the team gained insightful knowledge about how to design the code in order to more effectively use energy. In the end they settled on power breaking as the main method of stopping. Furthermore, energy analysis was much more crucial in the development of the actual AEV design. The results from that testing are shown below.

In term of energy the team did a good job of minimizing the frictional force used because of their lower mass compared to the class average. With any future modifications made the team wanted to be cognizant of not increasing the mass in order to keep a low frictional force. Furthermore, from this testing, the team realized that they had a low propeller force, so they modified the design of the AEV by changing the propeller configuration, which can be seen in the final design below.

 

These two designs were taken into performance test one, and it was seen that the modified propeller configuration, which is the second picture, allowed the AEV to preform much better, which is why it was chosen over the other design to go through the rest of testing. The breakdown of its final costs are shown below.

Part Price ($)
Arduino 100000.00
Electric Motors (2) 19800.00
Count Sensor (2) 4000.00
Count Sensor Connector (2) 4000.00
Propellers (2) 900.00
T-Shape 2000.00
T-Shape Arm 3000.00
Wheels (2) 15000.00
Battery Supports 2000.00
Angle Brackets (3) 2520.00
Screw Driver 2000.00
¼” Wrench 2000.00
Motor Clamps (2) 1180.00
Bulk Screws and Nuts 2.88
TOTAL COST: $158,402.88
TOTAL WEIGHT: 241 grams