I am trying to perform some dynamic analysis for a system with time varying parameters, and I am using Simulink block diagrams for this purpose. Since the model paramters varying with time, delay time for the signals is also varying.
Firstly, I modelled the dynamic system with constant delay time which gives correct results. Secondly, I tried to modify the system by inserting time varying delay blocks to represent a time varying delay system. However, the results I obtained from the model with time varying delay are not satisfying. There seems to be some high frequency response which is unexpected.
Here are the figures illustrating input and output of the system.
Is the model sufficient to represent a time varying delay system?
Is there a kind of stability problem, if so how can I overcome that problem?
Thanks
Hi Refet,
make sure you are Nyquist-sampling the time-varying parameters - that is, your sampling rate should be at least twice as large than the (band-limited) temporal variation of your parameters.
Also, make sure you have enough delay blocks to fully represent the temporal variation of your parameters.
Finally, make sure your update rate is small enough to assure the adaptation remains stable.
Regards,
-Paulo.
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