PID-autotune

A robust Arduino library for automatic PID tuning using the Relay Method (Ziegler-Nichols).

Features

• 4 Tuning Modes: Optimize for speed, stability, or disturbance rejection.
• Angular Logic: Native support for 360-degree systems like gimbals or servos.
• High Resolution: Uses microsecond timing for high-speed control loops.
• Failsafe Tuning: Includes safety timeouts to prevent hardware damage during failed tuning cycles.

Tuning Modes

The library supports several classic tuning rules via pid_tuner::mode_t:

Mode	Strategy	Best For
CLASSIC_PID	Standard ZN tuning. Aggressive response.	General robotics
PESSEN_INTEGRAL	Emphasizes disturbance rejection.	Industrial processes
SOME_OVERSHOOT	Balanced response with moderate damping.	Motion control
NO_OVERSHOOT	Most conservative. Eliminates peaks.	Temperature control

Quick Start

#include <pid-autotune.h>

PID myPid;
pid_tuner tuner(myPid);

void setup() {
  tuner.setTargetValue(100.0);
  tuner.setOutputRange(0, 255);
  tuner.start(); // Begins oscillation cycles
}

void loop() {
  double input = analogRead(A0);
  
  if (!tuner.isDone()) {
    analogWrite(11, tuner.update(input)); // Runs relay logic
  } else {
    analogWrite(11, myPid.compute(input)); // Runs tuned PID
  }
}