Step 4. Set Experiment Parameters
The frequency-response estimation experiment injects sinusoidal signals at frequencies
around the target bandwidth ωc:
- [1/3, 1, 3, 10]ωc for the Open-Loop PID Autotuner block
- [1/10,1/3, 1, 3, 10]ωc for the Closed-Loop PID Autotuner block
Use the Sine Amplitudes parameter of the blocks to specify the amplitudes of these
signals.
If your plant is asymptotically stable, the Open-Loop PID Autotuner block can estimate
the plant DC gain with a step perturbation. Specify the amplitude of this perturbation
with the Step Amplitude parameter. If your plant has a single integrator, clear the
Estimate DC gain with step signal parameter.
Caution
- Do not use either closed-loop or open-loop PID autotuning with an unstable plant.
- Do not use open-loop PID autotuning with a plant that has more than one integrator.
You can use closed-loop PID autotuning with a multiple-integrator plant.
All the perturbation amplitudes must be:
- Large enough that the perturbation overcomes any deadband in the plant actuator and
generates a response above the noise level. - Small enough to keep the plant running within the approximately linear region near
the nominal operating point, and to avoid saturating the plant input or output.
For more information about setting the experiment parameters, see the Closed-Loop PID
Autotuner and Open-Loop PID Autotuner block reference pages.
Step 5. Run Model and Initiate Tuning Experiment
After you have configured all the parameters for tuning, run the model.
- If you have configured a manual start/stop signal, begin the experiment when your
plant has reached steady-state.
PID Autotuning for a Plant Modeled in Simulink