The Concepts Screening and Scoring lab consisted of coding the AEV in the Arduino software to complete given sample tasks and then to evaluate the findings in concept screening and scoring sheets to determine which design would be continued. During the lab, the AEV’s coding and parts were checked on a stationary stand to confirm they worked properly. After inspection, the vehicle ran the code on a designated ceiling track and was observed. Using the findings, concept screening and scoring sheets were made to compare the sample AEV and 4 other designs.
The sample code, found in the Appendix, made both of the AEV motors accelerate to 25 percent power, stay at that speed for 2 seconds, and then run at 20 percent power for 2 seconds. After those tasks were completed, the motors were reversed and ran at 20 percent power for 2 seconds. The sample code provided enough power for a short period of time for the AEV to travel about 5 feet forward and 2 feet backwards. This was a good example of how far the AEV could travel given the conditions and will be used to determine the coding to get the AEV to complete the Jurassic Park challenge.
Concept screening and scoring sheets main purpose is to compare ideas to determine which design is best fit for the job. When completing the concept scoring sheet, Table 1.2 in the Appendix, it was realized the “Whip” design had no positive contributions so no part of it will be continued. In addition, the “ECC” design also had a negative net score in Table 1.2 so it will not be continued. The “RXF1” and “D-stroyer” design both showed promise and were further evaluated in the concept screening sheet, Table 1.1 in the Appendix. The “RXF1” received a higher weighted score than the “D-stroyer” so it was decided the “RXF1” would proceed.
The sample AEV was the only design that was actually constructed and used during the lab so all of the designs had to be compared to it. Table 1.2 shows that the “D-stroyer” was predicted to outperform the sample in every aspect except for weight because the design had a tunneling system built around the propellers while the sample had no system at all. The concept scoring table also shows that the “RXF1” and the sample AEV were similar in design but the “RXF1” was designed with lightweight weight in mind making it better in the balance, efficacy, and center of gravity categories. The “Whip” and “ECC” both scored lower in the concept screening sheet, Table 1.1, because the “ECC” design was very bulky which affected all aspects of the vehicle except for center of gravity and the “Whip” was small and condensed which added weight and ability to maintain the vehicle while the sample was very open.
Errors were found through out the lab that were identified early on and fixed. Within the AEV’s first couple runs on the ceiling track, the vehicle struggled to move forward but moved backward better than expected. This was resolved by flipping the propellers on the motor so that the dull side faced forward. It was observed during inspection on the stationary stand that the code was not running properly so the commands brake and reverse had to be applied to both engines to stop all previous commands and to confirm the engines were spinning in the direction wanted before the rest of the code was ran. These fixes will be used in future labs to make sure the vehicle runs properly.
The lab taught how to properly use concept screening and scoring tables to help determine which design will proceed. Experience with coding in the Arduino program was also gained. While running on the track, the AEV displayed it performs to different commands and how they affect the distanced traveled. Observing this will help determine the code to be used on the final AEV to travel the maximum distance using the least amount of power possible to achieve good efficiency.
Arduino Code
// “Reset” the engines
brake(4);
reverse(4);
// 1. Accelerate all motors from start to 25% in 3 seconds
celerate(4,0,25,3);
// 2. Run all motors at a constant speed (25% power) for 2 second
motorSpeed(4,25);
goFor(2);
// 3. Run all motors at 20% power for 2 seconds
motorSpeed(4,20);
goFor(2);
// 4. Reverse all motors
reverse(4);
// 5. Run all motors at a constant speed (20% power) for 2 second
motorSpeed(4,20);
goFor(2);
// 6. Brake all motors
brake(4);