Digital PID controller tuning using prefiltered ARX estimation

The use of prefiltered ARX (autoregressive with exogenous input) estimation to obtain reduced-order models that satisfy the Prett-Garcia (1988) digital PID (proportional plus integral plus derivative) tuning rules is described. The design of the prefilter is performed systematically using the engineer's desired control requirements and the setpoint/disturbance characteristics of the problem. The benefits of this method are shown for a fourth-order system.<<ETX>>