This week, we experimented with the NXT cars.  Below are the results of five trails.

NXT Tire Diameter: 5.5cm

Circumference: 3.14 (Diameter) (m) —–> 3.14 (5.5) (.01)= 0.172m

Percent of Error: Distance measured – distance computer / Average (distance ruler + distance comp. /2) * 100%

 

Trial 1: Time: 1 second;  Power: 75   Power 2: 75;       Rotation: 552     Rotation 2: 559;       # of wheel turns: 1.533

Distance: 26cm;     Estimated Distance: 29cm;       Velocity: .26 m/s      % Error: 11%

 

Trial 2: Time: 3 seconds;   Power: 75    Power 2: 75;       Rotation: 1789    Rotation 2: 1794;        # of wheel turns: 4.96944

Distance: 85cm;     Estimated Distance: 90cm;      Velocity: .2849 m/s      % Error: 6%

 

Trial 3: Time: 2 seconds;    Power: 50     Power 2: 50;      Rotation: 750     Rotation 2: 754;      # of wheel turns: 2.0833

Distance: 35cm;     Estimated Distance: 39cm;      Velocity: .179 m/s;      % Error: 11%

 

Trial 4: Time: 2 seconds;   Power: 25    Power 2: 25;      Rotation: 349    Rotation 2: 348;     # of wheel turns: .96944

Distance: 16cm;    Estimated Distance: 19cm;    Velocity: .0833 m/s;      % Error: 17.14%

 

Trial 5: Time: 1 second;   Power: 100    Power 2: 100;     Rotation: 784    Rotation 2: 792;      # of wheel turns: 2.17778

Distance: 37cm;    Estimated Distance: 39cm;    Velocity: .3745 m/s;    % Error: 5.26%

 

Throughout this experiment, we were seeing how far the NXT car went with different amounts of power and speeds, and then we recorded our results.  For our estimated distance, we were always fairly close to the actual computer measured distance.  I believe that out percentage of error never went over 12% because we paid close attention to the NXT car and how to set it.  However, our percentage of error could have been much lower.  For some reason, our NXT car kept veering towards the left.  I think it has something to do with the wheel rotations.  If you look at the numbers comparing rotation 1 and rotation 2, rotation 2 is always a little lower than rotation 1.  This experiment is important because it allows you to gain experience programming the NXT car, and then measuring the results.  Overall, I really liked this experiment, and I thought that it was very beneficial to this course.