The group worked with a reflectance sensor and a Servomechanism, collecting valuable data for the project as a whole. The reflectance sensor detected the output voltage of a surface, and graphed data when it passed over a material with a high output voltage, which implies that the surface is non-reflective. The servo was used to manage the angular position of the AEV. The use of the reflectance sensor and servo would help the group become familiar with new types of equipment that will be used for the final project. They would also aide the team in learning new programming commands that can be used in the project, as there are specific commands that can only be used with the reflectance sensor that will be worked with in the lab. Additionally, the lab’s focus on troubleshooting allowed the group to gain more experience and proficiency in the area of fixing software or hardware. Overall, the knowledge experience that was gained from this lab will benefit the group in its endeavor to efficiently design a quality AEV in the future. All of this was accomplished by first calibrating the reflectance sensor, then troubleshooting any errors that may have occurred, and finally writing two blocks Arduino code that would implement the new methods that are specifically used for the reflectance sensor.
The group built the sample AEV using the 3D model on Carmen before coming to the lab. During lab, the group started to work on installing the reflectance sensors. One of the problems faced when installing the sensors was the alignment of the sensors and making sure it was installed tight enough so that it would not slip off. After the reflective sensors were installed, the group opened the Arduino program on the group member’s computer that worked on the Arduino code for the previous lab. When the group decided to start the reflective sensor test, there seemed to be many issues that came about. The biggest issue was that the Arduino program did not compile and upload to the Arduino microcontroller. When the Arduino was connected to the computer via a USB cable and ‘Serial Monitor’ was opened on the Arduino software, with the baud changed to 115200, the team observed blank space scroll down the window instead of 1’s (what was expected).
Even though the group seemed to follow the procedure exactly as listed in the procedure, with the preferences of the Arduino software as used in Lab 1 as well as the battery and board being turned on, the team did not see the binary 1’s scroll down the screen apart from observing a string of words relating to the direction detected in the sensor. When this was observed, the wheel was shifted around but there seemed to be no effect on changing the direction of the wheel. One of these problems was that the wheel was not positioned correctly so that the reflective side of the wheel was facing the reflective sensor, but even after this was fixed and the Serial Monitor was opened once again, this did not fix the problem. At this point, whenever the group started the Arduino after the 4 second mark, the ‘Serial Monitor’ was observed to suddenly stop scrolling down to produce blank space. What the issue was and what the team learned at the end of the lab was that the file used for the sketchbook utilized in the first lab was not the same file used during Lab 02, and this resulted in multiple compiler errors which wasted much of the group’s time in the lab, resulting in the group not finishing Lab 02A. Therefore, the group was unable to test the AEV on track, and so the group is unable to deduce how the AEV behaved as well as determine whether the AEV could make it to the gate and stop.
The second part of this lab included testing with the wind tunnel to see what blade length and what configuration would provide the most power efficiency. One group member recorded the current, thrust, RPM, and % power of the wind tunnel test for a 3030 Pusher configuration and from that data, thrust calibration, efficiency, and advance ratio were calculated. The data used in the graphs and tables below is the sample data given to the group because the data collected in the lab yielded a negative power output, which is impossible.
Below is the table of sample data and calculations of the 3030 Pusher configuration.
Table 1: Sample Data for 3030 Pusher Configuration
Current (Amps) | Thrust (grams) | RPM | % Power |
0 | 146.3 | 0 | 0 |
0.1 | 148 | 2155 | 10 |
0.11 | 149.5 | 3123 | 15 |
0.19 | 151.5 | 4011 | 20 |
0.27 | 154 | 4290 | 25 |
0.4 | 157 | 5508 | 30 |
0.5 | 160.5 | 6227 | 35 |
0.61 | 164 | 6886 | 40 |
0.7 | 167.4 | 7485 | 45 |
0.8 | 171.7 | 8143 | 50 |
0.81 | 174.5 | 8742 | 55 |
1 | 181 | 9341 | 60 |
Table 2: Efficiency and Advance Ratio Calculations
Thrust Calibration (g) | RPM | Power Input (Watts) | Power Output (Watts) | Efficiency | Advance Ratio |
0 | 0 | 0 | 0 | 0 | 0 |
0.6987 | 2155 | 0.074 | 1.53714 | 20.7721 | 0.397230 |
1.3152 | 3123 | 0.1221 | 2.89344 | 23.6972 | 0.277342 |
2.1372 | 4011 | 0.2812 | 4.70184 | 16.7206 | 0.215941 |
3.1647 | 4290 | 0.4995 | 6.96234 | 13.9386 | 0.201897 |
4.3977 | 5508 | 0.888 | 9.67494 | 10.8952 | 0.157251 |
5.8362 | 6227 | 1.295 | 12.83964 | 9.91477 | 0.139094 |
7.2747 | 6886 | 1.8056 | 16.00434 | 8.86372 | 0.125782 |
8.6721 | 7485 | 2.331 | 19.07862 | 8.18473 | 0.115716 |
10.4394 | 8143 | 2.96 | 22.96668 | 7.75901 | 0.106366 |
11.5902 | 8742 | 3.2967 | 25.49844 | 7.73453 | 0.099078 |
14.2617 | 9341 | 4.44 | 31.37574 | 7.06660 | 0.092724 |
Code:
motorSpeed(4,25); //Run all of the motors on 25% power
goFor(2); //Do this for 2 seconds
motorSpeed(4,20); //Now run all of the motors on 20% power
goToAbsolutePosition(394); //Do this for 394 marks (which is ~192 inches, or 16 feet)
reverse(4); //Now reverse all of the motors
motorSpeed(4,30); //Now run all of the motors on 30% power
goFor(1.5); //Do this for 1.5 seconds
brake(4); //Now brake all of the motors
Team Meeting Notes
Meeting 2
Date: 28 January 2017
Time: 3:15pm-5:00pm
Location: HI 324
Members Present: Eric Fogle, Omar Mahboob, Xander Riggio, Matthew Spishakoff
Method: Face-to-Face
Meeting Objectives: Work on the Lab 3 Progress Report, along with organizing tasks and roles for the next week.
Roles for Meeting 2:
Eric: Week 2 Situation, Lab 2b Results and Analysis
Omar: Lab 2a Results and Analysis, Takeaways
Xander: Appendices, Proofreading and Final Submission
Matthew: Forwards Looking Plan
Tasks Completed in Previous Meeting
o Eric: Week 1 Situation, Results & Analysis, and Takeaways
o Omar: Schedule and Goals, Appendix, Editing the Document
o Xander: Week 2 Situation, Appendices, Proofreading and Final Submission
o Matthew: Created Project Portfolio, Lab progress report page, Website
Photos of our initial AEV design: