Energy Analysis
In this lab, the team worked to verify the AEV wheel count sensor system is accurate and working. This was accomplished by programming the Arduino and running it on the track. From this data, both the propeller and friction forces were calculated.
Mass of AEV: 270 g or .59 lbs
Program used:
- // Run all motors at 35% for 4 seconds
motorSpeed(4,35);
goFor(4);
// Run all motors at 0% for 10 seconds
motorSpeed(4,0);
goFor(10);
Data:
Trial group:
start: 342
stop: 175.5
Distance: 166.5 inches
Reflectance sensor distance; 196 inches
Trial will:
start: 40
stop: 225
Distance: 185
Reflectance sensor distance; 183.3
Graphs:
A plot of Distance x(t)-(m) vs. Time (s)
A plot of Speed v(t)-(m/s) vs. Time (s)
Progress Report Questions:
Describe the performance of the AEV wheel count sensors during the run on the straight track. What was the Marks Error? What did the team do to reduce this error?
The AEV wheel count sensors (reflectance senors), did not work properly for the first lab and did not record the distance the AEV traveled during any of the trials. Our group instead recorded manually where the AEV started and where the AEV finished. During the second lab we resolved the issue of the reflectance sensors and were able to records the distance the AEV traveled and plot the distance vs. time graph. Although the wheel count sensors worked they were still not perfect in recording the distance for each trial. For the Trial group the refelctance senors measured that the AEV had traveled 196 inches, but the AEV had actually only gone 166.5 inches. This error was caused by the count sensor not working correctly and was fixed for the second trial by us taking off the reflectance sensors and re loading the code for the sensors. In the second trial the reflectance sensor calculated 183.3 inches and the AEV had actually traveled 185 inches. This is a much more accurate reading and showed that the issue of the count sensors had been fully resolved.
Present the calculated forces (propeller, friction, and net) for the run on the straight track. What is the significance of each? What do these values say about the team’s AEV design?
For one of the team’s design, the propeller force was found to be 24.5 gmf and the friction force was found to be 16.3 gmf (in the negative direction); thus, creating a net of 8.2 gmf. For the second design, friction was found to be 17.7 (negative direction) gmf and propeller was calculated as 26.5 gmf – with a net of 8.8 gmf. The significance is that, in both instances, the force of the propeller was greater than that of the friction – resulting in forward movement. In regards with the designs, while the second design had a larger friction force to overcome, the propeller force was so much greater than that of the second that it had a larger net force propelling it forward.
Compare the performance of the team’s AEV to the other AEVs in the class average. How does the team’s AEV rank compared to others in the class? What can be done to improve the AEV’s performance?
NOTE: This question of the lab report, will be updated for the next website update.
Discuss any potential errors made and how these were resolved during the lab.
During the lab the refelctance sensors didn’t work well which caused error in the collection of data. The error in the reflectance sensors may have been due to the random error of us spinning the wheels after the trial ended, which would have added extra distance. This could have led to the large error that we obsereved in the group design trial. This error was resolved in the second trial where there was less of a deviation between the actual distance and distance measured by the reflectance sensors
Did the team need more guidance on any of the lab material or are there
recommendations to make the lab a better experience?
Yes we needed help to resolve the issue of the reflectance sensors that did not work the entire first lab. To make the lab better for everyone we would suggest more help offered for the refelectance sensor and how to actually run the reflectance sensor test. Although we figured out the issue eventually it would have been nicer to have resolved the issue in the first lab with help from a uta.