摘要：The paper investigates the behavior of digital PID self-tuning
controllers (STC) in different structures of the control loops used in adaptive
systems. In the two phases of this type of systems which use a STC-PID, the
first phase, i.e. the task of recursive identification of the plant model
parameters, is used a regression (ARX) model with the recursive least squares
method. Because the quality of process model depends on the order of the ARX
model and of the sample period (Ts), the digital PID parameters are functions of
these variables and, supplementary, of continuous-time PID parameters and of the
control loop structures used in the adaptive system (although, not so largely as
the firstly three variables). To see the latter influence, in this paper are
considered two control loop block diagram, and for simulations - three different
processes (stable; with no minimum phase; unstable), and some simulations with
different . The PID controller design method used to obtain the specs desired
for control loop dynamic behavior was the pole assignment method of the
loop.
