Progress Report – PT3

Full Report

Weeks 10-11

Situation

This week’s lab focused on development of the code to guide the AEV to course completion. The team completed two variations of code to bring the AEV to a stop in front of the gate, and analyzed both versions of the code for consistency and energy efficiency. The first code stopped the motors part of the way through the AEV’s travel, and let it coast to a stop in front of the first gate sensor. The second code stopped the motors before hitting the first sensor and immediately reversed them to act as a “brake” for the AEV.

Following analysis of both codes, the team used the concept second code (which braked the AEV) to develop the remainder of the course. Once the entire code was developed, the team continued to make small adjustments in order to ensure the reliability and accuracy of the code on both tracks. This was done in order to ensure the team developed and tested a code that could be agreed upon moving forward. Multiple code solutions were put alongside each other for the team to eliminate poor solutions, similar to how the designs were eliminated when put against one another. After comparing multiple solutions the team came to a consensus on a code to be used.

Results and Analysis

The approach taken by the team consisted of testing multiple solutions to each portion of the track. This generated multiple possibilities the team could use as software for the AEV. For example, stopping the AEV had two solutions. One solution used a high power setting of 80 percent power for half a second, while the other code used a 50 percent power setting for a full second. Considering the team’s objective with the code was to have a consistent product that can be reliable for final testing, the higher power setting solution was the better of both solutions. This solution brought the AEV to an immediate stop with little to no coasting, whereas the smaller power output resulted in a small amount of coasting of the AEV. Another noticeable discrepancy is the approach to the load. The two possibilities the team tested consisted of another high power reverse causing the AEV to stop near the load while shortly coasting afterward, or using a lower power setting from a distance away, allowing the AEV to coast into the load after braking. The team decided to use the second option which allowed for the AEV to coast into the load from a greater distance away. This option is not as consistent as the first, however, the difference is negligible. This approach bumps the load into the foam padding lightly, before carrying it back to the start position. This option was chosen with energy efficiency in mind. Less power was used to slow the vehicle, and it travels part of the distance to the load without using any power at all.

As the code now stands, the AEV accelerates until it approaches the gate at a steady pace before halting to a brake. This consists of approximately the first 13.15 feet of the track. The AEV then pauses for 7 seconds before taking off again. When the AEV begins to move it accelerates until it reaches its designated speed. After travelling 7.15 feet, 20.3 feet from the start of the track, the AEV will brake and use a light reverse to make the AEV coast the remaining distance to the cargo. This brake function is used on the AEV for 7 seconds. After this time is up, the AEV travels 13 feet to the gate at a constant power of 65 percent, more power than the 35 percent used for the AEV itself. After the first 12.5 feet, the AEV uses another quick stop to stop at the gate. After waiting 7 seconds, the AEV travels 13.5 feet with the load to the starting position and uses a light brake to take the cargo slowly to the starting position.

Takeaways

• AEV – The vehicle is much more consistent if it is “braked,” rather than being allowed to coast to a stop.
• AEV – The vehicle stops more consistently with a high power output in the reverse direction for a short time, than a lower power output used for a slightly longer time.
• AEV – The trip back with the load will use higher power settings and use more energy.
• General – It is helpful to test more than one solution to a problem—the results of both solutions may not be what you expect.

Week 12

Situation

In the upcoming lab, various sequences of code will be tested to see which best optimizes energy use for the AEV while traversing the monorail. Important factors to be analyzed include the power percentage the motors are set to while travelling the length of the track and whether or not to have the AEV grind to a halt or brake suddenly. These will be analyzed by using the MATLAB script and trying both methods, after which we will progress with the best performance. Because will not be an issue, the group is doing this to focus on using as little energy as possible to achieve the goal of an energy efficient vehicle. Additionally, a draft of the CDR oral presentation will be reviewed by the instructional staff on Thursday April 6 and feedback given that will be incorporated later when the actual CDR oral presentation is given.

Weekly Goals

• Complete a draft for the CDR oral presentation.
• Test various Arduino codes to see which is the most energy efficient.
• Find best power setting for the motors.

Weekly Schedule