>>12557145Well implementation of feedback is different depending on the system, for a digital system it could be an external sensor that converts the information into usable bits at some data rate, if it's analog it could be a more rugged physical device with a lower lifetime but uninterrupted signal. Practically the difference between the two would be the time taken to reach the output signal and its reliability or noise.
For specific applications, you'd have to look into real systems. For example here
>http://www-personal.umich.edu/~dsbaero/library/NonlinerFeedbackHysteresis.pdfthe author assumes a form of the nonlinearity for hysteresis phase portrait as a polynomial, which can be assumed for some form of the equation, or an empirical equation, but it's usually an unknown that has to be tested for. In real systems you just assume a model and test for all the possible known values and conditions.
Here's another pdf for linearization of feedback, basically stating all the conditions for a solvable linear system or if it can be linearized
>https://ocw.mit.edu/courses/electrical-engineering-and-computer-science/6-243j-dynamics-of-nonlinear-systems-fall-2003/lecture-notes/lec13_6243_2003.pdfSpecific examples would be just about any sensor on an amplifier that takes in data externally, hall effect, chemical detectors, temperature reading, etc. Aircraft would have rudder pressure, hydraulic, spring systems as feedback for dampening or stabilizing etc.
