During last class we were unable to connect the Robotic to the computer, therefore we moved the first experiment to this week.

Introduction:

In this experiment we are going to  present the relationship between velocity, distance and time.

We know the equation Distance  = Velocity * Time.

During the experiment we are going to connect the robot that we build from previous exercise to the computer with LabView, which contain the program that can move the robot. We can get the code from the Blackboard. In the code there are time, power, velocity, circumference, and the distance blocks. We are only be able to adjust the time, circumference and power blocks.

Procedure:

1. We have to measure the diameter of one of the wheels in order to calculate the circumference. In our case we have the diameter about 0.057 m. Following the equation we will be able to find the circumference. C = 2*pi*r=pi*d=0.057*pi=0.1790 m.

2. We set our time at 3 second. We do not want the time to be too short, because we want the robot to travel a certain distance in that case can help us to eliminate the error of the experiment.

3. The robot can only have the power range from 0 up to 75. We do not want to much power, because it will make the robot run out of the table. We picked 25, 50 and 65.

4. As we set up our constant time and power for three different trial. We hit the “run” program bottom on top of the windows. We are supposed to have 3 data for each power scale. Therefore we will have the average for each scale and total of 9 different trials.

5. We were doing the measurement on the table, so before we start we set the robot properly(make sure it will not run out of the edge of the table.). Then we mark the initial point, then we run the program. The robot will according to the power scale and time to move certain distance, then stop. We mark the final place for measurement by connecting two mark with a ruler, and record the data. On the screen, LabView will also gives us some data about the total distance and the velocity, we called it computer measurement since the calculation is doing by the instruments.

6. After we find all the data we are supposed to find the percentage error by using the following equation:

%error = [distance(measured)-distance(labview)/(measure+labview)/2] *100%

 

Table:

time (s)=3s
power 25	Distance (m)		Distance	Velocity (m/s)		% error
1	0.191		0.1939	0.0656		1.507
2	0.200		0.2033	0.0678		1.636
3	0.197		0.1979	0.0660		0.451
power 50
1	0.499		0.5087	0.1696		1.915
2	0.500		0.5062	0.1687		1.226
3	0.508		0.5146	0.1715		1.291
power 65
1	0.718		0.7215	0.2405		0.481
2	0.706		0.7170	0.2390		1.545
3	0.710		0.7190	0.3397		1.257

Conclusion:

This lab gives us a better idea about the relationship between time, velocity and distance. We were be able to confirm that distance is equal to time multiply by velocity. During this experiment we have some errors appeared in the table, compared to the computer’s data. The errors can comes from lots of places, such as the cable connecting between robot and the computer, or the mark that we put down for measuring. But in our group we were be able to control the error within 1.9 percent and some of them are with in 0.5 percent, which is pretty good.