A national park would like a monorail built over the park to give visitors a high viewpoint and to allow travel across the park. The park has a limited amount of energy to work with and as a result the monorail must focus on efficiency without being too slow. An AEV was designed to carry the passenger cart on the monorail. The three man group individual designed AEV’s and a final AEV was constructed with these restraints in mind. The AEV was constructed and experimented with over the course of the term. The AEV’s code was experimented with until the AEV completed the needed steps stated in the Mission Concept Review. All AEV will consist of motors, servo, propellers, Arduino Controller Board, battery, and an arm to attach to the monorail.
The AEV is limited on its design however. There are only a few set pieces from which to construct and keeping a low weight is vital. Because of the importance of weight, the AEV designs were small and as such it was difficult to find places to mount all of the components. The chosen AEV design was readjusted multiple times throughout its construction to account for this.
The AEV must perform a specific route across the monorail making various stops along the way. (See Figure 12) The AEV begins at the maintenance station and heads up the incline to pick of the passenger cart. The AEV then proceeds down the slope and past the maintenance station to the first stop. After the first stop the AEV then continues around the bend and stops before the second incline. The AEV will then climb the angled track and stop at the top to cycle out the passengers. After that the AEV reverses and stops at slightly different points back to the Grand Canyon Station to release the passengers one final time before returning to the maintenance station.
| Success Criteria | Reference | Design A | Design B | Design C |
| Cost | 0 | – | 0 | 0 |
| Complexity | 0 | – | 0 | 0 |
| Weight | 0 | – | + | 0 |
| Balance | 0 | 0 | 0 | 0 |
| Originality | 0 | + | – | – |
| Sum +’s | 0 | 1 | 1 | 0 |
| Sum 0’s | 5 | 1 | 3 | 4 |
| Sum –’s | 0 | 3 | 1 | 1 |
| Net Score | 0 | -2 | 0 | -1 |
| Continue ? | Combine | No | Yes | No |
Table 1: Concept Screening Scoresheet
| Reference: Example | Design A: Manta | Design B | Design C | ||||||
| Success Criteria | Weight | Rating | Weighted Score | Rating | Weighted Score | Rating | Weighted Score | Rating | Weighted Score |
| Balance | 20% | 2 | 0.4 | 3 | 0.6 | 2 | 0.4 | 2 | 0.4 |
| Weight | 20% | 3 | 0.6 | 2 | 0.4 | 3 | 0.6 | 3 | 0.6 |
| Cost | 5% | 3 | 0.15 | 2 | 0.1 | 3 | 0.15 | 3 | 0.15 |
| Originality | 40% | 1 | 0.4 | 4 | 1.6 | 1 | 0.4 | 1 | 0.4 |
| Complexity | 15% | 3 | 0.45 | 2 | 0.3 | 3 | 0.45 | 3 | 0.45 |
| Total Score | 2 | 3 | 2 | 2 | |||||
| Continue? | No | Develop | No | No | |||||
Table 2: Concept Scoring Scoresheet
Using results from System Analysis 1 and 2, better coding methods for the AEV were learned. The Analysis calculations and results gave useful information about the performance of the AEV with different codes. The propeller efficiency was tested for both two blade propellers and three blade propeller. As shown in Figures 2 and 3, the three blade propeller had a greater efficiency than two blade propellers, the two blade propellers were replaced with three blade propellers for better performance.
Figure 1: propulsion efficiency vs. advance ratio for three blade propellers.
Figure 2: propulsion efficiency v. advance ratio for two blade propellers.
Figure 3: Power vs. Time graph for design 1.
Figure 4: Power vs. Time with seven phases for design 1
| Phase | Arduino Code | Time(seconds) | Total Energy(Joules) |
| 1 | celerate(4,0,25,2); | 7.74 | 37.91 |
| 2 | motorSpeed(4,20); | 4.68 | 17.79 |
| 3 | brake(4);/goFor(2); | 2.1 | 19.46 |
| 4 | celerate(4,0,30,2); | 7.2 | 67.16 |
| 5 | motorSpeed(4,15); | 3.36 | 21.85 |
| 6 | celerate(4,0,flat,3); | 14.16 | 52.88 |
| 7 | goToAbsolutePosition(s2); | 1.8 | 12.59 |
| Table 3: arduino code, time and total energy of each phase for design 1. | Total Energy Used: | 229.04
|
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Figure 5: Power vs. Time graph for design 2.
Figure 6: Power vs. Time with seven phases for design 2
|
Phase |
Arduino Code | Time(seconds) | Total Energy(Joules) |
| 1 | celerate(4,0,25,2); | 6.36 | 33.30 |
| 2 | motorSpeed(4,20); | 0.96 | 4.92 |
| 3 | brake(4);/goFor(2); | 16.44 | 121.43 |
| 4 | celerate(4,0,30,2); | 10.08 | 31.70 |
| 5 | motorSpeed(4,15); | 18.90 | 118.85 |
| 6 | celerate(4,0,flat,3); | 1.80 | 7.49 |
| Table 4: arduino code, time and total energy of each phase for design 2. | Total Energy Used: | 310.20 | |
Under the same control program, the two concepts of AEV behaved a little differently. Design 1 seemed to accelerate faster and had less travel time than design 2. However, it is hard to tell if there were major effects from the battery while they were tested. The power vs. time graphs for both design looked very similar. Design 2 took longer time to reach the stop position of design 1. The power vs. time graph for design 1 was divided into seven phases as shown in Figure 4 and Table 3, and the total energy used by design 1 was 229.04 joules. Design 2 was divided into six phases as shown in Figure 6 and Table 4, and the total energy used by design 2 was 310.20 joules.