[JohnFogarty]

Let me see if I understand your intention correctly first. You want to create a state in which your motor does not back-drive?

There are two methods commonly used by tricks with mechanical and software.

There are multiples of methods for mechanically preventing a motor from back-driving, gear wrenches, some worm gears (efficient), and latching systems.

In software the most commonly used method is through PID positional control in which you control the movement of the motor towards a "setpoint" and then the software then applies incremental power when needed to keep the motor at the positional set-point.