This week in class we were again working with our Lego robots. The goal of this weeks lab was to calculate the percent error of how far the robot traveled at 3 different power levels. The first step was to calculate the diameter and then the circumference of the robot’s wheel. My partner and I found that the diameter of the wheel was approximately .05m. Now having the diameter we could calculate the circumference using the formula for circumference which is: c= pi or 3.14 x d. Plugging the diameter into this formula we found that c=.15m. This is the number we plugged into the lab view panel on the computer. 

After our robot was all hooked up to the computer we could begin having our robot move at the various power levels. We chose the power levels 25, 50, and 75. What follows is the data we recorded for each:

Test 1: Power= 25
Rotation 1= 325
Rotation 2= 326
# of turns=.9
Distance=.14
Velocity =.14

The distance we calculated=.20

Test 2: Power= 50
Rotation 1= 758
Rotation 2= 761
# of turns=2.11
Distance= .32
Velocity = .32

The distance we calculated=.42

Test 3: Power= 75
Rotation 1= 1183
Rotation 2=1187
# of turns=3.3
Distance=.49
Velocity =.49

The distance we calculated=.59

As I stated at the inception of this entry the main goal of this lab was to calculate the %error between what the computer says occurred and what we calculated the old fashioned way by measuring with a ruler. The formula we were given for % error was:

%error= measured distance – lab view distance / 1/2 (measured distance + lab view distance)

We computed this for each of the 3 power levels we tested and found that:

For Test 1 the % error was 27.03%

Test 2= 19%

Test 3=35.3%

What I got out of this lab was that although we sometimes believe that computers are always 100% correct this is not always the case. Because the robot was only traveling small distances we were able to do the actual calculations and find that although the computer calculations were close they were never  identical to the measured distances. 

Below is a picture of our robot during this experiment.