PID Tuning with <em>Jaiwen Bao</em>


This summary sheet compiles the tuning insights for the RotorFlight PID control loops as discussed by Bert Kammerer, Jiawen Bao, and Alex Dean. Please note that these are starting guidelines and final tuning depends on specific helicopter setups, servos, and head speeds. RotorFlight PID Tuning Summary Key Takeaways:
  • Filters: Always verify your filter settings (gyro section) first, as noisy signals can make PID tuning impossible. (3:00-5:40)
  • Tail Rotor: Treat the tail as a high-performance loop; the key is achieving a crisp stop. The ratio between clockwise/counter-clockwise stops is more important than the specific value. (28:45-31:20)
  • Iterative Process: Jiawen emphasizes that tuning is a trial-and-error process; always make small, incremental changes and test specific maneuvers (like tick-tocks or pitch pumps) to isolate which parameter needs adjustment. (17:19)
This comprehensive summary details the PID tuning parameters for RotorFlight as discussed by Bert Kammerer, Jiawen Bao, and Alex Dean. Always start by configuring your Gyro Filters (3:00) before adjusting PID loops, as noise can prevent effective tuning.

Core PID Parameters

  • P-Term (Proportional Gain): Acts like a spring in a suspension system (10:35). Controls the instant response of the control loop.
    • Roll: (30-70 range) Less critical than pitch (6:57).
    • Pitch: (90-150 range) More critical due to higher moment of inertia (9:06, 11:22).
  • D-Term (Derivative Gain): Functions as the damper in the suspension system (10:42). Helps prevent bouncing/wobble.
    • Roll: (0-50 range) Less critical (11:31).
    • Pitch: (45-60 range) Highly critical for stopping oscillations (11:46).
  • I-Term (Integral Gain): Maintains orientation (15:09). Use Piro-Pogo maneuvers to test; if the heli wobbles slowly, the I-gain is too high (16:27).

Advanced Tuning Parameters

  • Feed Forward (FF): Direct stick input to the swashplate, bypassing the PID loop initially (17:55). Too low causes undershoot; too high is rarely a problem. Jiawen recommends matching Roll and Pitch values (19:31).
  • Boost: Functions similarly to paddle simulation, increasing responsiveness during aggressive stick jabs (21:04).
  • I-Term Relax: Reduces wobbling during stops. Defaults are often too low; values around 12-15 are recommended to prevent a "loose" feeling (25:05).
  • HSI Offset Gain: Adjusts behavior in high-speed maneuvers like funnels or hurricanes. Increasing from the default (35) to 60-70 makes the helicopter more predictable (26:00).

Main & Tail Rotor Settings

  • Main Rotor Error Decay: Controls how quickly the heli returns to center. Recommended range: 15-20 (27:47).
  • Tail Rotor: Treat as a high-performance loop. Focus on the ratio between clockwise/counter-clockwise stop gains rather than raw values (28:45). If the tail whips during pirouettes, increase I-gain (up to 450 is possible) (23:09).

System & Rates

  • Response Time (Lua Menu): Adds a slight filter to inputs (7-15ms) to smooth out erratic stick movement, particularly useful for Piro-flips (41:20).
  • Rates (Actual): Center sensitivity defines the "flatness" of the stick curve, while Expo should generally remain at 0 for a linear feel (35:47).