Methods for Position Control of Non Linear Axis

I am working to better control a non-linear mechanism. Searching through the forums i have found only realtively old discussions. The most relevant is “Scaling Non-Linear Input” where by it describes taking your target, computing a scaled command, and thus reaching your target. Is there a new / better / alternate ways to control nonlinear motion? Any input, examples, suggestions would be greatly appreciated.

A bit more:
This is a purely mechanical mechanism currently with SSI feedback.