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# Group 4
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## Lab Notebook 8
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**Date:** 05/05 2015.
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**Group members participating:** Tine Hansen, Daniel Moltzen, Mads Eriksen, Lars Høeg.
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**Activity duration:** 42 hours.
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## Structure
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The report is structured as follows;
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- Goal: The goal for the lab report.
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- Plan: What are we going to do.
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- Motor Test: Here we experiment with different motors.
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- Lego Car - Using Light Sensors: Results from experimenting with completing the Alishan track.
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- Final Results: Contains our final results and what we have done to reach our goal.
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- Conclusion: A summary of our findings and results.
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## Goal
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The goal of this Lab Report is to build an autonomous Lego car that drive as fast as possible following the Alishan train track.
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## Plan
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We are planning to achieve the goal, by conducting several relevant experiments. First, is to test the motors that we are using, because that we have seen, in previous lab sessions, that the Lego car, we have build, tends to drift to the left or right when it should drive straight forward. Then when the motors are in place, we will decide on a design for our lego car.
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In relation to our previous experience, we are planning to build a Lego car that uses two light sensors and follows the line up- and downhill. We could also use a color sensor, but we saw in a previous experiment that we could detect the green stopping and starting area by use of just light sensors. Even though, we are still planning to make a test to see if can get better results following the line with a color sensor, or to see if combination would be beneficial.
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A Lego that completes the Alishan track by the use of sequential steps have also been brought up. We think it could be interesting to experiment with as well, however in regards to what we have been told about this technique at the lectures, our focus will be on the use of light and/or color sensors.
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## Motor test
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In this section we will try to find two motors with the same power output - We have in some of our previous exercises seen that the robot have difficulties driving straight forward. This is due to the motors not having the same power output, even though we send the same power to both motors. This unfortunately results in the robot drifting to one direction.
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![MotorTest](http://gitlab.au.dk/uploads/u4099/legolabtimadala/926fc1e16f/MotorTest.jpg)
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##### Picture 1: Setup motor test - inspired by [1].
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Researching for others that have experienced the same problems with motors not performing the same way, led us to a site that contains a motor test for the Lego motors[1]. The test helped us to find two nearly identical performing motors as seen in video 1 below.
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[![image alt text](http://img.youtube.com/vi/wqnneXyvkh4/0.jpg)](http://www.youtube.com/watch?v=wqnneXyvkh4)
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##### Video 1: Motor Testing
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The motors that we originally used through the other lab reports, was not performing in the same way according to the test, which concludes what we suspected. When conducting the test, the motors have to stay flat all the time for performing at the same rate - if not - one will kick up as seen in the video.
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