1. Overview/Purpose (RACHEL) (1:00 minute):
– Smart City Columbus: safe and energy efficient transportation between Linden and Easton
– Mobility, aerodynamics
– Complete course within 2 minutes
– Energy efficient, fast, low cost
—
2. Design Development (TATUM)(1:30 minutes):
– In the team’s Preliminary Research and Development, we learned the basics of how the AEV functions from the sample AEV. After a few weeks of being exposed to the AEV concept, every team member created an AEV design. The designs were then compared to each other based on weight, aerodynamics, flexibility, amount of materials, speed, and cost. First, a concept screening matrix was used to compare the designs to the sample AEV using a plus sign if it was better than the sample, a minus sign if it was worse, and a zero if it was the same in that category. This Matrix showed us that the TW and MK were best to move
forward with. TW and MK ended with positive scores while PB and RR ended with negative scores.
– After the screening matrix evaluation, the team decided to weight the categories in a concept scoring matrix to give precedence to cost, aerodynamics, and amount of materials. With this method, TW and MK once again scored the highest. Due to these conclusions, TW and MK were taken into high consideration when creating the final team design. MK’s design did not have many materials which therefore made it lighter and cost less. TW’s design had wings that focused on aerodynamics and speed.
—
3. Research & Development (PAIGE) (1:45–2:00 minutes):
– In the first R&D, our team investigated three motor configurations: two pusher motors, two puller motors, and one pusher and one puller motor. When testing one pusher and one puller motor, our AEV didn’t move since we had both motors on the same side of the AEV. Having an AEV design with motors on opposite sides of the AEV would have fixed this problem. After all the tests, we found that the pusher motors travelled 0.565 meters farther in 1.53 seconds less than the other methods. Although the pusher motors used 0.545 watts more power, the pusher motors’ ability to control the AEV is worth the extra power.
– In the second R&D, we investigated the use of a servo brake by testing the AEV with a servo brake and with it coasting to a stop. The servo brake allowed the AEV to stop 0.14 meters sooner, but it required 4.13 watts more of power. We decided that with our current brake arm, which was made of coffee stirrers and connected to the servo with masking tape, the servo brake was not a viable option due to the extra amount of power it used. However, if a more stable brake arm was designed and attached to the servo better, the servo brake could be a valuable solution to braking inefficiencies.
– Since we didn’t use the servo brake, we decided to brake the AEV by reversing the motors with the celerate(); and goFor(); commands for a brief period. In the final R&D, we investigated changes in the time parameters of these commands. We varied the celerate(); time parameter from 0.25 to 1 second and the goFor(); command from 0.5 to 1.25 seconds, with increments of 0.25 seconds in between. The celerate(); command had an ending range of 0.136 meters and the goFor(); command had an ending range of 0.31 meters. The test that made it the farthest between the two sensors without passing the second sensor was when celerate(); was at 0.5 and goFor(); was at 1. Overall, the team decided that the default brake should be celerate(); at 0.5 and the goFor(); at 1 second, and the celerate command should be used for small adjustments and the goFor command should be used for large adjustments.
—
4. Final Design (MIHO):
Performance Test Improvements:
– Use of reverse function and goFor function: the team decided to use the reverse function after the performance test 1. Due to inconsistency during the performance test. Team had to make adjustments in the distance where motors to brake.
– Pusher method: pusher method was used
Design Details:
– Pusher method: from R&D 1 pusher method was determined as better motor configuration
– Reverse function: reverse function is used to better stop the AEV
– Approximate weight: xxxx g: the AEV design is xxxxg lighter than the original AEV
– Energy Consumption: xxxx J: the AEV used xxxxJ of energy to travel the track
– Travel Time: xxxx sec: the AEV took xxxx sec to travel the track
—
5. Total Cost (RACHEL) (1:45 minutes):
– Capital cost = materials = $152,691
– Additional cost = no safety violations, but 1 extra lab session was $25,000
– Performance Test (best two runs count): baseline energy cost $125,000 ($500/joule), baseline time cost $90,000 ($1.5K/ sec)
– Total cost: $802,571.05 out of the $50 millions, but not under $500K
—
Recommendations:
– Keep separate code for the tracks in different rooms. The slight variations in the tracks resulted in our AEV performing differently
– Reduce energy usage
—
6. Citation (RACHEL) (0:15 minutes):
– Preliminary R&D, Advanced R&D, User manual (motor, servo)