Potential Errors

Analysis

The battery testing lab revealed that the battery system utilized for this research will reliably provide sufficient power for our AEV. There was no observable drop-off in power delivered by the battery over repeated test runs on the track by a sample AEV. L Division’s AEV did not experience any power issues for the duration of testing.

During testing of the final 2-motor configuration, the AEV did consistently slide once power was cut to the motors. Cutting power to the motors caused the belt, and in turn the wheels on the monorail, to immediately stop movement. Because the AEV still possessed significant forward momentum, it did slide on the rail for approximately 6-8 inches. This distance was calculated into the marks used by the reflectance sensors and subtracted from the “goToRelativePosition()” command given to the AEV. This resulted in performance tests that were within the margin of error for the gates, loading, and drop off zones.

During initial testing of the 3-motor design, the system was too unstable and continuously threw the belt off the pulleys, resulting in aborted test runs. It was observed that the central motor belt pulley was not rotating around its central bore and introducing extreme amounts of vibration and instability to the belt system. This irregularity was a result of errors in the manufacturing process. The erratic movement of the pulley resulted in repeated instances of the belt being thrown off the pulleys during testing. Because of this, L Division was forced to abort the use of a third motor and revert to its previous 2 motor design. Once the third motor was removed, the stability of the system was greatly improved and only minor adjustments were required before the final performance tests.

The true monorail length on the incline and decline portions for the Performance Test were not initially taken into consideration, only the straight-line distances provided in the MCR were considered. Upon discovery, the true length of these sections were calculated and considered. The true length of the first incline was calculated as 48.0416 inches. Compared to this section’s straight-line distance of 48 inches, it was decided that these small changes in elevation would not significantly contribute to the overall length of the monorail and were disregarded. These small changes in distance are cumulative, however, and may present an error over repeated runs.

During the final testing of L Division’s two-motor configuration, it was discovered that there were significant differences in the actual distance traveled by the AEV when the Arduino instruction included the same number of marks.

 

 

The data above does not show a discernible pattern and this type of variation continued to be an issue throughout the testing of the initial 2-motor design and the 3-motor design. The final design, a refined version of the 2-motor design, did not exhibit the same variances in true distance traveled when given a constant relative position in the code instruction.