How to evaluate a close-loop control during transient? I have implement a close-loop control in order to perform the tracking of the desired signal R.
The basic scenario shall be summarized as follow:



I have to evaluate the performance of my control G with a moving average value of the Error E.
When there is no transient the error E shall be less then a certain threshold. 

But, how to relax the threshold during transient ?
Addition info:


Frequency of R is limit to 2 HZ
Rising time is 200ms
Control G has a 1 Hz band (but this is not a problem)
I can acquire R E U and Y
Real-time FFT of R is not possible during execution.  


My idea is to find a threshold as function of r signal which is small when reference is stationary (constants from at least 200 ms) and high when the reference is fast changing. 

Thank you all
Regards
In order to evaluate the performance of a controller during transients, you can use different metrics. Two metrics you could use are

ITAE= $$\int_0^{\infty} t*|e| \,dt$$ 

ITSE = $$\int_0^{\infty} t*e^2 \,dt$$ 

where e is the difference between your reference and the measurement and t is the time since the reference change.

Basically, you want to minimize these metrics. The basic idea is that an error in the beginning won't impact the metric much while an error 1 second after the reference change will impact your metric much more.

There are probably other metrics you could use. You could also use stabilization time at 1% or 5%.

Edit : If your signal is cyclical you could limit the integral upper bound to a limited number of 2-Hz cycles.

ITAE= $$\int_0^{NT} t*|e| \,dt$$ 

ITSE = $$\int_0^{NT} t*e^2 \,dt$$ 

where N is a whole number and T is the period of your reference signal.