Week 6
Situation
This week the team was tasked with evaluating all the AEV designs and testing the best designs. In order to make the design testing more efficient designs were eliminated using the concept screening method. The team first discussed the main attributes that were important to have for the AEV design, the team agreed on balance in turns, aerodynamics, center of gravity, efficiency, durability, cost, and weight. Afterwards each design was compared to the reference AEV which was built using the lab manual’s design with a plus if it was better than the reference AEV, a minus if worse or a 0 if equivalent. Overall 5 designs were tested, four of which were designs created by each individual team member and one created by the team as a whole. The team then discussed how important each category was and then added weighted scores to them accordingly using percentages. The designs that were chosen to move on were then given a score from 1-5 for each of the categories then the weighted score was calculated using the percentages assigned to each category. The design that scored highest was chosen to move on but the materials needed to build it were not available so the second highest scoring design was chosen to test. The design was tested using a sample code provided in the lab manual to be tested on the straight track. The categories chosen for screening were evaluated while the AEV was running and afterwards data was downloaded from the AEV to evaluate efficiency.
Results and Analysis
The AEV on the test code ran as expected. It was designed to be very balanced and have the center of gravity directly underneath the track so that it would not lean to either side. It was also designed to be very lightweight which helped it move at 25% power very smoothly, because of this the AEV was also balanced during the turns. When the motors were reversed the AEV came to a complete stop then went in the reverse direction for a small distance before coming to a stop.
Tables 1 below show the concept screening and scoring worksheets the team went through to decide upon a final design. Table 1 has 7 success criteria. The first is balance in turns, this criteria is important because if the AEV does not stay balanced in the turns it will likely fall off of the track. Next is Aerodynamics this success criteria is important because if the AEV is not aerodynamic it will use more energy than is necessary to get around the track. Center of Gravity is important to the AEV because it will determine in part the balance the AEV has in the turns and how well it stays on the track. Efficiency is similar to aerodynamics in that it looks at how easy the team thinks it will be for the AEV to get around the track using as little energy as possible. Durability this is an important criteria because in the case of an accident the team does not want the AEV to break completely. Cost was added because the design needs to be affordable enough that it is reasonable for the team members to create it. Finally weight is important because if the design is too heavy it will not be as efficient and will use up more energy. Using these 7 criteria the team judged each of the design AEVs to the reference AEV created in lab 2. Using these criteria the team narrowed the design options down to Axay’s design, Cole’s design, and the group’s design before progressing to the concept scoring. These designs were selected primarily because of their superior aerodynamics, efficiencies, weights and durabilities. Nick and Sky’s designs were not continued with due to their increased weight, lack of balance in the turns, increased cost and poor center of gravity in reference to the sample AEV.
Table 1: Concept Screening
| Success Criteria | Reference | Axay | Nick | Sky | Cole | Group |
| Balanced in turns | 0 | 0 | – | – | 0 | – |
| Aerodynamics | 0 | + | + | + | + | + |
| Center of Gravity | 0 | 0 | – | – | + | 0 |
| Efficiency | 0 | + | 0 | – | + | + |
| Durability | 0 | 0 | 0 | 0 | + | + |
| Cost | 0 | – | – | – | – | 0 |
| Weight | 0 | + | – | – | 0 | + |
| Sums +’s | 0 | 3 | 1 | 1 | 4 | 4 |
| Sums 0’s | 7 | 3 | 2 | 1 | 2 | 2 |
| Sums -‘s | 0 | 1 | 3 | 5 | 1 | 1 |
| Net Score | 0 | 2 | -2 | -4 | 3 | 3 |
| Continue | yes | no | no | Yes | Yes |
After the concept screening was complete the team moved on to the concept scoring, whose results can be found below in table 2. To perform the concept scoring the team placed weights on each of the success criteria above. Efficiency was given the most importance at 25% because the main goal of this project is to create the most energy efficient AEV. Balance in turns, durability and center of gravity were all given 15% because of their importance to the AEV staying on the track and surviving even if it does fall, both of which are important to completing the goals of the project. Aerodynamics was also given a 15% due to its large impact on the efficiency of the AEV. Weight was given a 10% due to the fact that all the AEVs selected were relatively small and light. Finally cost was given the lowest importance because all the remaining designs were not likely to cost the team anything financially. Using these guidelines the team decided the best to designs would likely be either the design created by Cole or the groups design.
Table 2: Concept Scoring
|
Success Criteria |
Weight | Axay | Cole | Group |
| Balanced in turns | 15% | 3 | 4 | 2 |
| Aerodynamics | 15% | 4 | 5 | 5 |
| Center of Gravity | 15% | 4 | 5 | 4 |
| Efficiency | 25% | 3 | 4 | 4 |
| Durability | 15% | 3 | 4 | 5 |
| Cost | 5% | 3 | 3 | 3 |
| Weight | 10% | 3 | 4 | 5 |
| Total Score | 3.3 | 4.25 | 4.05 | |
| Continue | No | Yes |
Yes |
Takeaways
- Control the speed of AEV carefully so that it won’t fly away the rail.
- Accelerate functions may be useful for conserving energy
- When the AEV starts the motor it originally uses an elevated amount of power before lowering to a constant power
- Getting the AEV up to speed uses a lot more energy than keeping it up to that speed
- Use reverse to help stopping the AEV
- More tests should be conducted using different functions
Week 7
Situation
For this week, our group needs to test Cole’s design which we didn’t get to last week. This is our best design and the one we will go forward with so this is very important. This lab is a halfway checkpoint that brings together the introductory and background stuff with performance testing and design iterations. In this lab, we will work on our oral presentation and get help from the instructional team as they come around to help us with that and to check our portfolios.
Weekly goals
- Complete Progress Report for Lab 05.
- Complete analyze for Lab 05 data.
- Complete PDR presentation worksheet.
- Complete Lab 06.
- Complete Lab 06 Progress Report first draft.
- Update Website as needed
- Create 3D final design solidworks for AEV concept.
Weekly schedule
Table 3: Week 2 Schedule
| Task | Teammate(s) | Start Date | Due Date | Time Needed |
| Regular group meeting | All | 2/18/17 | 2/18/17 | 1.5hrs |
| Analysing lab 05 test data | All | 2/18/17 | 2/21/17 | |
| Backward result & analysis | Axey, Cole | 2/18/17 | 2/21/17 | |
| Forward situations | Nick | 2/18/17 | 2/21/17 | |
| Group meeting notes | Cole | 2/18/17 | 2/21/17 | |
| Schedule & goal setting | Tianyang | 2/18/17 | 2/18/17 | 0.5hr |
| PDR presentation worksheet | All | 2/21/17 | 2/21/17 | 1hrs |
| Lab 6 procedure | All | 2/22/17 | 2/22/17 | 2hrs |
| Regular group meeting | All | 2/25/17 | 2/25/17 | 1hrs |
Appendix
Team meeting notes, 12pm to 1:30pm, Thompson Library, All members
Purpose of meeting: Complete this progress report, complete the PDR presentations worksheet, watch the sample presentation videos for the bonus video and finally plan out and create a schedule for what needs
- Tasks completed from last meeting
- Students completed lab 5 and understood the concepts it presented
- Narrowed the choice of AEV designs down to either Cole’s Design or the groups design using concept scoring and screening.
- More data was recorded and analyzed during the team’s AEV testing using the data recording and analysis tools.
- Team created and tested an AEV based off our designs.
- Tasks to be completed for next meeting
- Watch and critique the sample videos for the bonus video(tuesday, everyone)
- Finish the PDR presentation worksheet (everyone)
- Progress 5 (everyone)
- Complete lab 6 and understand the concepts it presents(Wednesday, everyone)
- Decisions made by the group
- There will be an additional meeting tuesday after lab to begin discussing work on the bonus video
- The AEV design that we use will either be the group AEV design or Cole’s AEV design
- Reflections from last assignment
- Last week there were no roadblocks during the lab everything went smooth and the team was able to test the AEV and record data
- No deadlines were missed in previous week
- No work was substandard, or differing expectations, or other conflict
- In future, it might be beneficial to build one of the team’s concept AEVs before doing the data recording and analysis lab, this way the data that is recorded will be more relevant to the final AEV
Arduino Source Code
- reverse(2); // reverse motors to make AEV move forward
- celerate(4,0,30,3); // accelerates both motor from 0 to 40 in 3 s
- motorSpeed(4,35); //set both motors at 35
- goFor(1); // run both motor for 1 s
- motorSpeed(4,40); //set both motor speed on 40
- goFor(2); // run both motor for 2 s
- reverse(4); // reverse both motors
- motorSpeed(4,25); // set both motor speed on 25
- goFor(2); // run both motors for 2 s
- brake(4); // brake both motors