Topic and Team’s Approach:
The culmination of all the previous tests lead the team in fully optimising the design and its code to complete the mission concept review in accordance with the team’s approach in speed. With multiple trials done a final design was made. This test in completing the MCR is used as a basis for the AEV design that are too be used for the Columbus smart city initiative. Budget and safety are the two main concerns. The team in focusing on speed, looked to cut the budget. This was followed through with the ability to allow the AEV to remain safe for the passengers.
Analysis of Results:
The group through these test runs began developing a new code that does not rely on time but rather on position. This means that absolute and relative position commands were done where measurements can be used to allow the AEV to fire its power breaking commands at correct positions. This would allow for increased consistency and as seen in figure 7 with no accuracy penalties and in the complete run data collected in figures 10 and 11, it suggests this was a good move to make. A detailed code change can be found in appendix D where iterations and the different code for rooms 224 and 308 is found. The initial tests done have yielded results of completed runs but further development needs to be done to minimize the power consumption and time of each run. Further goals and expectations can be found in the forward looking section.
Because the team needed to optimise its focus on speed by decreasing joule consumption and time so that the total cost of the AEV run is decreased. So, the team turned to motorspeeds and how it can be optimised to decrease run time while also not increasing joule consumption too much. With the data collected, the team analysed energy consumption between motorspeed power of 25% and 35%. The data collected in figure 12 suggests that the 35% cuts costs by about 944 dollars due to its ability to trim away time. The added joule consumption was thus counteracted by the decrease in time. Moreover, the precision of the run which can be found in figure 7 was not hindered as the accuracy penalties among two runs remained at 1 (no error in the run).
As stated, the accuracy of the runs were the highest possible which allowed for additional savings when considering safety. There was however a $50,000 safety violation which substantial hurt the team’s budget. However, as far as capital costs the team was able to cut unnecessary parts while still maintaining a design that had good stability on the track. The rectangular battery holder drop down design from prototype 1 which though added to the capital cost allowed for greater stability as the center of mass was centered in the middle of the AEV. With all of this in mind, figure 7 breaks down the total cost.
Potential Error:
Error like that found in performance test 1 and 2 can be attributed to track variance, temperature difference, voltage variance, and heating up of the battery and or motor. All of this as stated in performance test 1 and 2 can attribute to inconsistencies. It should be noted that the team did get over much of these challenges (that is further explored in the conclusion). One change that could attribute to the inconsistent results for this performance test would be the use of the reflectance sensors that track the distance traveled of the AEV. As they do rely on light, lighting in the different rooms tested could change, thus throwing off the results. However due to the many different variables in play for the success of the AEV, not all precautions could have been done perfectly. Thus, while the design and code is optimised for reproducibility of runs, there were still some distance traveled changes as well as joules consumed. Nonetheless more of this is explained in the following conclusion that answers and provides solutions to the team’s problems as well as future research in advanced energy vehicles.
Conclusion:
The team went ahead and reworked their code based on position functions in which the AEV will fire certain functions such as power braking, motor cutoffs, and motor reverse commands only at certain positions that are reached by the AEV. This meant that error found from the motors or battery heating up won’t make as big of an impact on the AEV’s run. For example, if the AEV for some inconsistent reason was not as powerful and thus was traveling less distance in the same amount of time as a previous run, it will still fire its power braking command (that also would be less powerful) at the same exact positions. As far as the inconsistencies of changing rooms, the use of the two code system was fully optimised, performing identical results. The team also chose 35% as the motorspeed power in the first half of the run while also tweaking and utilizing power braking on the hills.
The advanced energy vehicle as designed by team could be improved by cutting more parts off through researching what essential components are needed for stability. Moreover, the code could be more greatly optimised to utilize power braking and coasting which as stated was the main concern for the team.
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