Division R AEV Research

Final Performance Test:

The cost for the final performance test was $538,755 with a time of 44.47 seconds using 223.34 Joules of energy. A plot of the final performance test can be seen below. Overall, the AEV was observed to be very efficient making crisp stops and completing the tasks with the fastest time out of all companies.

Performance Test 2:

The second performance test had the same requirements as the first performance test but the AEV also had to connect to a load at the end of the track and pause for 5 seconds.

Performance Test 1:

The first performance test required the AEV to stop between gate sensors, stop for 7 seconds and proceed through the gate. This was achieved with the most recent AEV design and a servo rotation of 50 degrees.

Advanced Research and Design Week 1-  Coasting vs. Power Braking

Pros and Cons

Two potential ways to brake the AEV are coasting and power braking methods. Coasting cuts off the motors so the AEV will naturally brake while power braking uses the reversing of motors to halt the AEV. Benefits of coasting are less energy usage and reliable braking distances. Benefits of power braking are indifference to path taken and a smaller braking distance. Coasting has disadvantages in having a larger braking distance than power braking and that it may not work as well on different surfaces. For example, if the AEV is on an incline part of the track, coasting could be variable due to no control over the motors. The main drawback from power braking is that it uses more energy, however, the difference in energy consumption between the two is not extreme.

Collected Data:

 

Moving Forward:

Moving forward, Group R will use the method of power braking. Although power braking uses more energy, it is a more reliable and concise way to get the AEV to brake. It is essential for the AEV to brake at certain points and coasting provides too much room for error.

Advanced Research and Design Week 2: Servo Testing

PROS VS CONS OF SERVO USAGE

Pros of using the servo

  • Has many possible usages, although we tested it as a brake.
  • Allows the AEV to stop faster than coasting.
  • Uses less power than power braking.
  • Can be used in conjunction with power braking for added safety.

Cons of using the servo

  • Added weight means added energy.
  • More parts means more could possibly break.
  • Uses slightly more energy than coasting.

PROS VS CONS OF POWER BRAKING VS COASTING

Pros of power braking

  • The AEV stops quicker
  • Safer than coasting
  • Confidence of customer is increased

Cons of power braking

  • The AEV has more weight added
  • Added weight will make more energy needed to be used to make the AEV accelerate and decerlate
  • More parts =more maintenance, more things can go wrong
  • It uses energy to brake, coasting uses none

Power vs. Distance

In this plot, there is a significance spike in power consumption in two places, followed by rapid declines. The first spike occurs over the first third of a meter, and  where power consumption reaches 6.11 watts. This is due to the AEV starting up, then finding a balance of energy around 3.75 watts. The next spike is more extreme, reaching about 9.0 watts. This spike is larger because of the reversal of the motors, and then the re-acceleration in the opposite direction. Additionally, it is around 1.33 meters that the track inclined. The AEV was fighting the incline of the track, and required more power as a result.

Power vs. Time

The AEV accelerated gradually as the motors started up. Power consumption plateaued between 3.5 and 6 seconds, and then spiked rapidly as the motors reversed around the 6th second. Once the propellers reversed and the AEV began to move in the other direction, wattage plateaued again around 6.11 watts, until power was cut at around 8 seconds.

 

 

 

General Research and Citations

Exercise 1- Programming Basics:

In this exercise we became familiar with basic programming and how the motors respond to the code. In the first scenario, there was some resistance observed in the motor to rotate the propeller at low speeds. Overall, the electric motors worked but there was trouble getting them to do all of the commands in the code. This issue was caused by not putting enough braking in the code but was resolved. From learning how the motors worked, we decided to put the motors closer together for our AEV.

Exercise 2- External Sensors:

Exercise two required us to further our knowledge with the coding and learn how the reflectance sensors worked. We found that the commands used in this lab could limit the success of the AEV because the timing of the braking is not immediate. It takes the AEV time to understand the code and implement it, so the AEV will not stop right away.

Exercise 3- Creative Design Thinking:

Each group member made a rough sketch of their vision of what the AEV should look like. Based on these sketches, a team sketch was made from compiling the best parts of each design. Factors considered during the design process were weight, safety and time efficiency. A heavier weight was favored due to knowledge about cables potential motion and the need for the AEV to remain stable throughout the whole track (Irena Gobiowska).

Gobiowska, Irena. “Air Flow around Suspended Cables.” EPJ Web of Conferences , 2 Feb. 2017, doi:10.1051/epjconf/201714302028.