Lab Result 6: Braking vs. Coasting

In this lab, Team K prepared two codes for the testing: power braking vs. coasting.

  • Team K tested three times for the coasting and three times for power braking.
  • Team K didn’t follow the lab procedure on Carmen for this lab. Instead, we used two groups of code for power braking and coasting. For the coasting vs. power braking lab, our group used the code celerate(4,0,25,3) to accelerate the AEV and motorSpeed(4,25) to keep it moving. But for each run, the motorSpeed code ran for a different time ranging from three seconds to five second. This allowed us to get the information about the coasting distance and power corresponding to the time the motors ran. For the braking test, we changed additional codes for the reverse code to increase the time for the braking period according to the time of keeping the constant speed. We concluded that the pros and cons for power braking is that braking can make the AEV stop at a more accurate location than coasting, but braking uses more power. For coasting, it is hard for the AEV to land on a precise location, but it can save more power than braking.
  • The plots for the braking and coasting are below:

1. Power vs. Distance for Power Braking:

PowerBrakingDistance1 PowerBrakingDistance2 PowerBrakingDistance3

2. Power vs. Time for Power Braking:

PowerBrakingTime1 PowerBrakingTime2PowerBrakingTime3

3. Power vs. Distance for Coasting:

Coasting1 Coasting2 

4. Power vs. Time for Coasting:

Coasting3 Coasting4

  • Figure 1: Energy difference between each test for coasting and power braking

  • Figure 2: Braking distance of coasting and power braking

  • According to the data above, we can see the energy difference between each test. The energy differences for coasting are generally smaller than the energy differences for braking. We can conclude that coasting can save more power than power braking. With the data related to the braking distance, we concluded that the power braking can make the AEV land on a much more accurate location. From the plots we got from Matlab, the lines corresponding to the braking distance are almost vertical lines, and the braking distances are almost 0.0m for all three tests no matter how we increase the rate of acceleration.
  • So, Team K decided to use power braking in the future since power braking can make AEV land at a precise location, which is needed for our mission concept review.