High-Speed Line Follower Robot with IR Sensor Array & PID Control in Arduino

Line-following competitions test precision sensor calibration and mathematical control loop tuning. Basic bang-bang control results in sharp oscillations and wheel shudder. By implementing a full Proportional-Integral-Derivative (PID) algorithm, the robot anticipates turns, decelerates into sharp chicanes, and accelerates along straightaways.

1. Hardware Requirements

• 1× Arduino UNO or Nano
• 1× 5-Channel or 3-Channel TCRT5000 IR Sensor Array
• 1× L298N or TB6612FNG Dual DC Motor Driver
• 2× High-RPM Micro Metal Gearmotors (100–300 RPM)
• 1× Lightweight Acrylic / 3D-Printed Chassis & Caster

2. PID Algorithm Implementation

cpp
float Kp = 25.0;
float Ki = 0.0;
float Kd = 15.0;

int P = 0, I = 0, D = 0, previousError = 0;
int baseSpeed = 150;

void calculatePID(int error) {
  P = error;
  I = I + error;
  D = error - previousError;
  previousError = error;

  int correction = (Kp * P) + (Ki * I) + (Kd * D);

  int leftSpeed = constrain(baseSpeed + correction, 0, 255);
  int rightSpeed = constrain(baseSpeed - correction, 0, 255);

  setMotorSpeeds(leftSpeed, rightSpeed);
}