Power vs. Time Plot
The above plots shows the Power (Watts) vs Time (seconds) of our first track run. The AEV was programmed according to the instructions of the lab outlined below:
It is expected that the power will fluctuate with any change in motor speed. The Power vs. Time graph displays this right off the bat. The first command calls for all motors to accelerate from 0% to 25% in 3 seconds. During the first 3 seconds, the power required steadily increases until the propellers achieve a rotation fast enough to maintain the commanded speed. The second command continues this speed for an additional second and is noticeable from the first command by the flat line appearance. The third command runs all motors at 20% power for 2 seconds. The reduction of power can be seen by the noticeable drop around the 2 second mark. At the 4 second mark, the 4th command is run and a significant amount of power is required to reverse the direction of the motors. The 5th command resumes a constant speed at 25% power for 2 seconds. The power required to operate the motors forwards and backwards is similar. At around 6 seconds, the 6th command is executed, and all power to the motors is shut off. This is signified by the steep drop in power and eventual flat line as the Arduino saves data about the recent run.
Power vs. Distance Plot
Unlike the Power vs. Time graph discussed above, the Power vs. Distance graph is less conclusive. The AEV only completed a total run of 1.25 meters (~4 feet). The track the run was completed on is not level the entire time. There is an incline shortly after the beginning. This will be taken into account during the graph analysis. Significant power was required to move the AEV initially. This is mirrored also when the AEV switches directions around the 0.85 meter mark. These observations are consistent with Newton’s first law which can be briefly summarized into “objects at rest tend to stay at rest while objects in motion tend to stay in motion”. Once the AEV was in motion, the power required per meter was consistent. This was also true in reverse except the power required in reverse was more than that required in the forwards direction. This makes sense because the propellers are oriented to work better in one direction. At the end of the Power vs Distance graph, a unique feature can be seen. Even though there was no power, the AEV continued to move. This effect is labeled coasting and will be one of the focuses moving forward.