Pick a process model, set its parameters, and let IMC tuning rules
compute the PID parameters automatically. Compare setpoint and
disturbance step responses as you adjust the model or the desired
closed-loop time constant λ.
Transfer function with parameters
Current numerical transfer function
Smaller λ = faster, more aggressive response. Larger λ = slower, more robust.
Kc — τI — τD — τF — Setpoint step
Disturbance step
Unit step disturbance enters at the process input; setpoint held at zero.