... | ... | @@ -62,3 +62,24 @@ Through this experiment we learned that gearing the motors causes significant pr |
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We can conclude that gaining momentum is not necessarily an advantage for the robot as it comes with a cost of increased vulnerability to its driving behavior. If we were to maintain control of the robot, it would require a significant amount of code to prevent the robot of going into a spin. This could be done using a PID controller to perform frequent corrections to the power distributed to the wheels.
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Though a PID controller could improve the robot’s stability, we must consider that part of the robot’s behavior is caused by frictional problems. This means that though a PID controller may control the power, the wheels will still rotate at at very high rate and thus making the robot slide. This problem may be solved using wheels with a larger radius, or by implementing an acceleration behavior to the robot.
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## Experiment 2: The Race car with one light sensor.
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### Task
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For the second experiment we want to obtain a more controlled robot. To do this we abandon the idea of gearing the wheels and stick to a more traditional build with the motors powering the wheels directly. Additionally we implement a PID controller in order to follow a black line precisely.
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### Plan
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To build a race car robot with wheels mounted directly to the motors and a light sensor to be used for the PID controller.
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### Results
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We built the robot as seen in fig 3 with the light sensor mounted in the front. This makes it easy for the robot to follow the car. When the wheels are directly mounted to the motor the build can be made pretty simple. Though in our case the design evolved into a dragster looking race car.
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![Racecar](http://gitlab.au.dk/uploads/group-22/lego/6a9646c9fd/Racecar.jpg)
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##### Fig. 5: The Racecar robot with swingarm with one light sensor mounted on it.
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#### Flexible front mount
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As an addition to the sensors mounted in the front of the car, we decided to make the whole front of the car flexible (see Fig. 6) We knew from lab lesson 1 that the light sensor reading vary according to the distance from the sensor to the surface. By doing this we made sure that the sensors mounted to the front would always keep the same distance to the surface which can be a challenge when the robot drives over the plateaus (see fig. 6).
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![sensorDistancesThis](http://gitlab.au.dk/uploads/group-22/lego/d7f438caf8/sensorDistancesThis.jpg)
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##### Fig 5: Indicates a robot approaching the hill on the racetrack. It shows why the flexible front mount is preferred to a static mount as it makes sure that the distance to the ground is the same regardless of the angle. |
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