ARRUDA, G. H. M.; http://lattes.cnpq.br/7628771206086042; ARRUDA, Gustavo Henrique Machado de.
Abstract:
I n this work new frequency domain relay based closed loop experiments and a new PID
controller tuning technique are presented.
Controlled oscilations at the plant output with the proposed relay experiments are
obtained i n a closed loop operation. Given a closed loop system and a chosen transfer
function, the frequency at which the chosen transfer function achieves a user defined gain
is determined.
The Loop Transfer Function and Sensitivity Transfer Function are the chosen transfer
function considered in this work. The estimated frequency points of the Loop Transfer
Function are used to obtain a reduced order plant model. The Sensitivity Transfer Function
experiment is used for evaluating performance and stability of the closed loop.
The P ID controller tuning is based on the symmetrical optimum approach, which has
well defined performance and stability properties. Frequency domain least squares is used
to obtain the controller's parameters. The proposed method is more general than the
original one and yields Loop Transfer Functions that are symmetrical optimum in a least
squares sense for a frequency range of interest.