In general, for smooth movements/rotations, be sure to always include the system-variable "time_step"
into any calculation of distance-to-travel or change-in-rotation TO DO within this "frame".

And also be sure to always include the system-variable "time_frame" into any
calculation of distance-travelled or change-of-rotation THAT WAS DONE within the "last frame".


I cant be more specific that that, as actual usage varys widely depending on the formula that you have created.
This is a tricky part, but get it right, and things will move smooth regardless of "twitchy" FPS...