Welcome Passengers!
Take a ride to the Future! Throughout the semester Group I has worked hard to make the best AEV for the passengers on board! Through trial and error the team has added many components to the final AEV that ensures it is the safest, energy efficient, most cost effective AEV made possible. Thank you for choosing the Future!
Figure 1: Final AEV Design
This image depicts Group I’s final AEV design, used for the final performance test. This design includes a two motor configuration, servo, and a light weight design.
Safety:
Going forward from performance test two, the biggest issue the team saw was the inconsistency with the coasting distance and where the AEV stopped in relation to the gate. This led the team to devote the third round of aR&D to the servo function. Adding the servo ensured that the AEV would stop at the right location and when needed. It is important for the passengers safety that the AEV has a breaking system rather than relying on the AEV to just cost to a stop.
For the servo testing, there were two situations tested with three trials done. The two situations included a precision test and a time and energy efficiency test. The precision test was done first so that the team could get an accurate idea of the stopping distance the servo provided. This information would be a key piece of information that would help the team with coding going forward. The team’s goal with the second test was to determine the added cost the servo would bring to the final budget. For test two, distance was maintained by running the first test without the servo and seeing the total distance that the AEV traveled. The trial with the servo included using the motor for a longer time and then stopping at approximately the same distance as the first trial. Overall, the servo demonstrated that it was worth the extra $5,950 in cost due to the precision it provided.
The team determined code that would be the most beneficial in using the servo. The code allows the arm of the servo to go up and make contact onto the track, this caused friction and stopped the AEV, at the right distance. Overall the team decided that the servo was worth the $5,950 because it is needed in order for the AEV to be reliable and safe for the passengers on board.
Figure 2: Total Energy vs. Time for AEV Servo Test
This test helped the team determine how much more energy the servo was going to use. The servo does use more energy, like the team predicted, but, it was concluded that the more energy used was worth it for the AEV to be safe.
Figure 3: Distance vs. Time for the AEV Servo Test
This test helped the team determine how accurate the AEV would be with the addition of the motor. When the same distance was set on the AEV, meaning the motors would cut when the certain distance was reached, the AEV with the servo stopped at the correct distance and the AEV with out the servo kept going. The team decided that the servo was worth the extra energy and cost.
Efficiency:
An important factor for the final AEV design was energy efficiency, to do this the team choose to look at motor configuration in the hopes of making the AEV the most efficient and successful design possible. The team’s testing of motor configuration showed concise results that allow the team to move forward with confidence in the AEV. Comparison between the four different motor tests showed that using two motors at full power resulted in the best outcome. This can be see in the data as two motors at half power produced no movement and one motor used more time with energy varying depending on front and back. This leads the group to two motors at full power resulted in the shortest time to complete the test as well as only having a marginally higher power consumption. Going forward, the team will use two motors at full power to complete all tasks.
For the motor configuration aspect, the team designed four configurations to test. The test consisted of accelerating, going to absolute position 246 and then coasting to a stop. The team’s current AEV design put one motor on each side (opposing). These four configurations were tested because they were all possible combinations for the AEV’s current design. After each test, the AEV data extraction test was used and the total time, distance, power, and other vital information were put into an excel chart to allow for easy comparison.
Figure 4: Power vs. Time for 3 Trials of Motor Configuration
The three functioning trials for the motor configuration tests are depicted in the image above. This helped the team determine which trial will be the most efficient. It was determined that trial 2 required the most power of the 3, it was also the quickest to accelerate and could shut off the motors more quickly, allowing it to have a bigger advantage in the long run as it was able to go a faster speed. Trial 1 required power to be input in small amounts a few times per second in order to keep coasting, so it would have been more inefficient in the long run. Trial 4 required the least total power input of the three trials considered, however its max velocity was considerably smaller than that of trial 2.
Affordability:
Group I determined early on that the AEV should be affordable to the passengers using it. In order for the AEV to be affordable to the passengers the group had to keep costs as low as possible without compromising the passengers safety. The final budget will incorporate a lot of factors including, time on the track, energy, and parts on the AEV final design. For time and energy used the team looked at motor configuration and use of the servo to keep costs low, as can be seen in the Safety and Efficiency section on this page!
Another important aspect of keeping costs low is what parts are on the AEV for the final performance test, the team knew it was vital to keep the design light weight to keep down how much power would be needed to push the AEV through the track and would benefit the group by not having a lot of room for extra added parts that would only increase price.
The heavier the AEV would allow for more friction with the wheels so there will be no chance for slipping but also means that it will require more energy from the motors which will increase cost. This success criteria will define how easily the AEV slices through the air and this will also play a role in the Time-Energy Efficiency category. A better score for aerodynamics relates to have a front and back end that allows for better airflow such as using covers like bullet trains use. Time energy efficiency, is crucial aspect of the AEV as the group have to stay within the budget and time and energy are both aspects that will factor into the budget. Each second will cost the group $1.5K but each joule will cost $500. This category explores how quick the AEV design can go while still fitting in the guidelines. Center of mass for the AEV relates to how hard the motors will have to work in order to accelerate and decelerate the AEV so therefore the group wants the design to have the mass concentrated in the center. This will also allow the AEV to be more level and not have a chance of falling off the tracks. Finally, size matters when it comes to the AEV’s as the group need it to be able to fit within the gates of the “stations”. This also relates to center of mass because having a larger size means a more spread out mass distribution.
Unity:
Group I worked hard to create a safe, efficient, and affordable design that would benefit the passengers to its fullest. As seen in Figure 1, the final design is a far cry from the original sample design made in the beginning of the semester. This new design was made with passengers in mind. Although it was made to be more aerodynamic than previous designs, it’s main selling point is the new and improved total mass of the AEV itself. By lowering the total mass, the group was also able to accomplish a much more centralized center of mass. This allowed the AEV to be more efficient and travel a longer distance overall. Figure 3 gives an example of the improved distance vs. time representation of the new and improved AEV.
This improved design will allow more passengers than ever to come aboard. The previous design was known to carry less passengers as there was less clear board space left after placing the battery, Arduino, and various cords. This new design places the battery on the arm of the AEV itself to allow more space for passengers. By doing so everyone will be able to ride on this AEV. The AEV has come a long way since the beginning of the semester. To see just how much the AEV has changed its design, refer to the “Evolution of Design” page, where the group notes exactly what was changed, and why that change was made. A major selling point to note is the motor configuration. The configuration has changed many time over the semester. It began with two motors, then was changed to one, and finally back again to two motors. Not only did the amount of motors change, but so did the configuration of where the motors themselves were placed. Passengers will see how ideally the motors are placed. One is in the back, to allow for the AEV to be as fast and efficient as possible. The second one was placed below the AEV itself. This allowed passengers to board the AEV safely, and minimize the chance of injuries from coming in contact with the motors.
In conclusion, passengers should know that The Future of AEV’s are in good hands. Group I’s AEV was made to be not only safe, efficient, and affordable, but also a unified AEV meant for everyone. It will be one of the first all inclusive AEV’s that won’t turn away passengers for being too full.
