Lego Mindstorm EV3 Autonomous Car

LEGO Mindstorm EV3 Autonomous Car with PD Control that regulates velocity depending on front distance and stays between two white lines.

Contributors

This project has been done by these contributors, be sure to check them out! :

• Doramas Báez Bernal

• Kevin David Rosales Santana

• Borja Zarco Cerezo

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Construction

Car uses two motors, one of them for a rear-wheel drive system and the other one for an Ackerman Steering Geometry for front wheels.

Car Overview:

Car contains these sensors:

• x1 Ultrasonic Sensor:

  

• x2 Color Sensors:

  

Implementation

This project contains these files:

1. car_project.py: Project Main. You can find the Closed-loop System Structure and the Learning System.

2. direction.py: Car Steering File.

   1. Class LineSensor returns a movement depending on Color Sensors Values.
   2. Class Direction tries to get the car into a desired position (Between white lines).

3. leds.py: Class LED update LEDs Colors.

4. speed.py. Car Speed File.

   1. Depending on distance, car may go in reverse, stop or accelerate. In this last case, it will take a speed that depends on this Sigmoid Function:

      (exp(0.075*x+0.3) / (exp(0.075*x + 0.01) + 4.7 )) - 0.36

      Sigmoid Function Plot (Velocity [0-1] vs Distance [0-120]):

      

Learning System

To avoid car getting on white line repeatedly, a learning system was designed and developed. It's about allowing the car turn for a longer time if it has been staying on white line many times.

A Speed Reduction System was made too for these curves.

Both Systems can be found in car_project.py

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We hope you've learned some useful knowledge thanks to this Project. Thank you for visiting it!

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