Week 9
Situation
This week the team developed and tested arduino code. Initially, the team planned on developing one code at a time and moving on to the next code when the first was running to the team’s standards. The team wrote and tested the code on part at a time. The first part was getting to the gate, from there the code was tweaked so that the AEV would stop before it triggered the second sensor. From there, the time of the stop was added and tested. Once that was done, the code to get to the caboose was added then the servo spin was added. Then, the caboose carrying portion was able to be added because the team received the lasercut hanger arm that was needed to connect to the caboose. The team left off with testing the portion of the run where the AEV takes the caboose to the gate.
Results and Analysis
During the testing process the team was unable to test two separate codes. The team had planned on testing one code that involved using a reverse function and one code that did not use any reverse functions for braking. The team started by testing a code without reverses. Unexpectedly the AEV consistently stopped at the same spot on the track without need for a reverse. The team then decided that as long as the AEV continued to consistently stop in the same position it would be unnecessary to test the second code which uses reversing. The team reasoned that the code that uses reverse would use more energy due to the extra energy used to stop the vehicle. Additionally, the development of a complete first code was severely limited due to the team’s inability to obtain the AEV arm in time. This setback made it impossible for the team to attach the AEV to the cargo. The result of this was that the team was only able to work on the first section of code until the last day. The team also experienced difficulties with the transition from the 309 room to the 224 room. For whatever reason the team was unable to get the AEV to consistently stop at the same spot in the 309 room until the end of the class. Because the team did not account for this difficulty in changing the code, this setback also contributed to the team’s ability to test a second code. Despite these setbacks the team still made many important discoveries over the course of the lab. The first and most important realization that the team made was that it our AEV’s single motor will be strong enough to propel the AEV along the track, which was a concern after the cargo carts were replaced with newer heavier carts. Also as can be seen in the figure 1 below the total energy used for the run was about 83.4 joules. This run included travel to the cargo and then the return to the gate with said cargo. Compared to energy uses reported by other teams the energy usage of our AEV appears to be very competitive. The final beneficial observation that was made in this lab is that the motor is able to run at very high percent powers without loss of the propeller. This was initially a concern of the team but even when the AEV was run at 90% power the propeller did not fly off of the motor. Another benefit of the code 1 over a code that uses reverse is the simplicity of the code. Our code will be much shorter than if it utilized reverse. This will make future changes to the code much
more easy which will also makes tests in future labs easier to perform.
Table 1 below gives a breakdown of the AEV. To meet the requirements listed in the MCR our AEV begins by running the motors at 35%. The motors run at 35% for about the first 2.4 meters of the track before stopping. The AEV then coasts to the gate where it waits about 8 seconds before the motors once again begin running at 35%. Shortly after the AEV goes around the second curve the motors once again shut off. At the point our AEV rotates 180° and coasts into the cargo. Once connected to the cargo the AEV will wait for 5 seconds to ensure the cargo is connected. The motor will then start again at somewhere between 65-90% power and begin traveling the 4.2 meters to the gate. When it about halfway through the curve the AEV will cut power to the motor and drift the rest of the way to the gate. Once at the gate the AEV will again wait 7 seconds for the gate to open. Once the gate is open the motor will run at 65-90% power and travel back to the starting position.
Table 1
| Operation | Distance/ Time requirements |
| Travel to the Gate from Starting position | 4.2 meter |
| Wait for gate to open | 7 seconds |
| Travel to the Cargo | 4.3-4.4 meters |
| Connect to the Cargo | .1 meters |
| Wait to Ensure the cargo is connected | 5 seconds |
| Retrun to the gate | 4.2 meters |
| Wait for gate to open | 7 seconds |
| Return to Starting Position | 4.3 meters |
Takeaways
- The team will perform the final test of the AEV in room 224
- Use of the reverse(m) function is uneccessary
- The single motor configuration will be strong enough to easily carry the cargo
- A more simplified code will be used for the final AEV project
- The team will need to create and test a second code in the next lab
Week 10
Situation
This week the group will continue to make variations to our current code to get the AEV to stop exactly where we need it to stop in order to complete the task. This will involve adding subtracting marks. We will also introduce a second type of code that will have a reverse motor function call that will brake the AEV. The AEV tests have shown that the coast-stop method can be unreliable so the brake method may be more consistent. This week we will also look at power settings on different phases on the run to decide what is most energy efficient. This is important because different power settings need to be utilized in different phases in order for energy efficiency to be achieved.
Weekly goals
- Complete Progress Report for Lab 09
- Complete final code for room 224
- Make new code with reverse
- test the best power with cargo
