Closed-loop performance
PID control applications - Temperature and position control

Closed-loop performance is evaluated by carrying out tests characterizing the transient regime of the measurement y, when the setpoint y_d' varies.

• The indicial test (or step test) in a closed loop (figure 4) consists in abruptly changing the setpoint y_d (y_d is a step), starting from a steady state, and observing the transient state of the y measurement.

  This transient regime (figure 4) is characterized by the following criteria:

  • D %, the closed-loop index overshoot that characterizes the system's degree of stability, $D\text{\%}=100\frac{\left(\text{Δ}{y}_{\text{max}}-\text{Δ}y\right)}{\text{Δ}y}$;

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