COELHO, F. S.; COELHO, Flávio Sousa.
Abstract:
In this work contributions to system identification the time domain are presented. The
contributions are in the area of identification of systems in open loop, for step response tests,
as well in the area of identification of systems in closed loop, for the reference signal varying in
the step form.
The method of identification of systems in open loop proposed uses least square to obtain
the parameters of models of first and second order plus dead time. The equations of regression
of these methods are simpler than the methods existing in the literature.
With the input and output signals of the process and using the de-convolution method the
step response of the system can be found. In the case of real systems, with the noise presence,
these signs have to be filtered. The chosen filter was the filter of phase zero, that is to say, a
filter that doesn't give phase contributions to the signals. The proposed method of identification
of systems in open loop can be extended to identify systems in closed loop, so that process
models of first and second order plus dead time can also be found.
