In the last we did, we made a car robot, and programed it with Labview. The goal was to measure by two different methods (ruler method, and LearSmart program on the computer) the distance the car travels, compare those results, and then calculate the percentage of error. Here are the steps we followed:
First step,
_ run the program to make the car move
_ measure the distance the car travels with a ruler
_ calculate the wheels’ rotation corresponding to this distance
_ calculate the time corresponding to this distance
In the second step, we use the LearnSmart program:
_ measure the diameter of the wheels with a ruler
_ calculate the circumference of the wheel
_ put the circumference on the front pannel
The computer gives directly the time, and the number of turns.
FORMULAS
_ Circumference= pi * diameter
_ wheels’ rotation= distance / circumference
_ time= distance / velocity
_ average distance= ( distance1 + distance2 ) / 2
_ Percentage of error= (|Distance1 – Distance2| / Average Distance ) * 100
We did two trials with different power levels, and the results are below:
_ Power of 50
Time: 2.5 seconds,
Distance1: 0.335meters
Distance2: 0.310 meters
Wheel rotation: 1936
Velocity: 0.1549m/s
Error % : 7.75
_ Power of 75
Time: 3.5
Distance1: 0.81m
Distance2: 0.748m
Wheel rotation: 4675
Velocity: 0.2493m/s
Error % : 7.79
In conclusion, the distance given by the computer is more precise than the ditance we got by measuring the distace with a ruler. We also notice that the car’s performance increase with the power.
Here is a link to a photo of the Car Robot:
http://sites.suffolk.edu/jtl192/files/2012/09/DSC_01351.jpg