For the automatic tuning of PID controllers, a new identification algorithm
is proposed to identify frequency data sets of the process. It guarantees
better accuracy and can provide much more frequency data sets of the proces
s than the previous describing function analysis algorithms. The identifica
tion method provides exact data sets for all desired frequencies and it als
o gives the exact data set corresponding to the relay frequency even in the
presence of a static disturbance. (C) 2000 Elsevier Science Ltd. All right
s reserved.