Dear Jai Dev,

I have used a PID controller for a nonlinear synchronise machine. Please look my patent under

Patent Verfahren und Vorrichtung zur Spannungs- und Blindleistungsr...

Couldn't really understand the question, but perhaps you mean an adaptive controller for a complex nonlinear system. There is a plenty of methods to adapt the parameters including gain-scheduling and fuzzy logic. Did you try feedback compensation?

Hi,

it is easy, the recent versions of MATLAB (2012 and later) are able to tune automatically  the parameter of PID controllers, by linearizing nonlinear plants. open PID block and use the tune option.

PID can be tuned optimally for nonlinear by applying performance index (PI) using ISE; IAE or ITAE concepts i.e. PID gains can be find.

Hello Jai Dev Sharma,

The recent versions of MATLAB  are able to tune automatically the parameter of PID controllers, you can see the link below, i hope that will help you.

http://www.mathworks.com/help/slcontrol/automatic-pid-tuning.html

Please refer to these articles:

https://www.researchgate.net/publication/313576646_From_PID_to_Nonlinear_State_Error_Feedback_Controller

https://www.researchgate.net/publication/312046377_Improved_Sliding_Mode_Nonlinear_Extended_State_Observer_based_Active_Disturbance_Rejection_Control_for_Uncertain_Systems_with_Unknown_Total_Disturbance

https://www.researchgate.net/publication/309655805_On_the_Improved_Nonlinear_Tracking_Differentiator_based_Nonlinear_PID_Controller_Design

Article From PID to Nonlinear State Error Feedback Controller

Article Improved Sliding Mode Nonlinear Extended State Observer base...

Article On the Improved Nonlinear Tracking Differentiator based Nonl...