Ten hours line follower hackathon as part of the final project for Introduction In Robotics 3rd year course.
Task: The robot must follow the line as accurate as possible in order to finish the track. The robot has 3 tries to get the best time.
Team: R2D2
Members:
- Ion Alexandra
- Postolache Miruna
1.Arduino Uno
2.Zip-ties
3.Power source - LiPo battery
4.2 Wheels
5.Wires set for the line sensor (female - male)
6.QTR-8A reflectance sensor, along with screws
7.Ball caster
8.Extra wires from the rest of components (male - male)
9.3D printed Chassis
10.Breadboard - medium (400pts)
11.L293D motor driver
12.2 DC motors
First it is better to start by changing just kp value.
Increase the value if the robot can not do a turn;
Decrease the value if the robot do not follow the line becouse of overshooting
After finding a resonable kp value, next step is to change kd value by
Increasing till the robot doesn't wobble to much and also takes better turns.
The final values for PID control
float kp = 140;
float ki = 0;
float kd = 180;
Other tries
BEST CASES
//Case 1: follow the linie roughly, slow
baseSpeed = 150;
float kp = 5;
float ki = 0;
float kd = 0;
//Case 2: follow the linie roughly, slow
baseSpeed = 170;
float kp = 7;
float ki = 0;
float kd = 2;
WORST CASES
//Case 3: not follow the linie
baseSpeed = 160;
float kp = 6;
float ki = 0;
float kd = 0;
//Case 4: not follow the linie
baseSpeed = 200;
float kp = 5;
float ki = 0;
float kd = 1;
//Case 5: not follow the linie
baseSpeed = 160;
float kp = 5;
float ki = 0;
float kd = 0;
For CALIBRATION it is used autoCalibrate function where the robot moves left and right
in order to understand the difference between black and white.
He first goes to the right, then to the left and so on.
Calibration covers all sensors.
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For the right move, the robot will have the following motor speeds:
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right motor: -200
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left motor: 200
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For the left move, the robot will have the following motor speeds:
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right motor: 250
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left motor: -250
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These values were chosen after several attempts.
🎥 Watch the robot on the circuit in the final round: youtube video here
