I am working on a problem where I need to implement auto tuning PID control using Ziegler–Nichols method. Basically I want to control temperature using it. The PID has to be implemented with the Microchip PIC 18F microcontroller.
However, I have no knowledge of the system's transfer function. So, how can I implement it?
Also, I would appreciate any good docs to read about it. I had read about Ziegler–Nichols method. The problem I encountered is to find the ultimate gain and ultimate period.
We need to get Kp such that the system is oscillatory for step input. but as a temperature controller I am unable to implement that in a dynamic system.
What can be the possible solution?