Wally Line-Follower: PID Algorithm for Precise Black-Line Tracking

🛣️ Wally Line-Follower — PID for Precise Tracking

🎯 Line-Follow Principle

• Black tape → absorbs IR → low reflectance
• White floor → reflects IR → high reflectance
• Judge deviation direction by the left/right sensor reading difference

🧮 PID Three Terms

Term	Meaning	Role
P Proportional	Current error × Kp	Fast error response
I Integral	Historical error sum × Ki	Eliminate steady-state error
D Derivative	Error change rate × Kd	Suppress overshoot & oscillation

🔧 Parameter Tuning

1. Tune P first: increase until the robot oscillates on the line
2. Add D: reduce oscillation amplitude for smooth motion
3. Add I last: eliminate fixed deviation
4. The three parameters interact — test repeatedly