PID Controller for Rust

A proportional-integral-derivative (PID) controller.

Features

• Visibility into individual contribution of P, I, and D terms which often need to be logged for later analysis and parameter tuning.
• Output limits on a per term basis.
• Mitigation of integral windup using integral term limit.
• Mitigation of derivative kick by using the derivative of the measurement rather than the derivative of the error.
• On-the-fly changes to kp/ki/kd.
  • Mitigation of output jumps when changing ki by storing the integration of e(t) * ki(t) rather than only e(t).

Assumptions

• All calculations use f32.
• Measurements occur at equal spacing. (t(i) = t(i-1) + C)
• Output limits per term are symmetric around 0 (-limit < term < limit).

Todo

• [ ] Three-term output limit: MAX(p + i - d, global_limit).
• [ ] Support f64 via generic type parameters.
• [ ] Helper for (auto-)tuning by detecting frequency & amplitude of oscillations.