One more use of "dithering", although this may show my age.
Back in the 60s and 70s, dithering was used in the earliest electrohydraulic servo controls to minimize the breakout friction present when the control was first commanded to move.
A high frequency, very low amplitude electrical signal was continually sent to the EHSV (electrohydraulic servo-valve). This was called a dithering signal. This kept the moving parts (EHSV coils, control spools and hydraulic actuator pistons) in constant motion, but of such small amplitude that there was no effect on the airplane (or whatever) the system was installed in.
When a real control input came along, there was no static friction to overcome before things started to move.