[MrForbes]

I think it might work. As mentioned, it will probably be able to be backdriven, meaning the arm will fall down unless you keep providing power to the motor...but the motor doesn't like to sit in one place with significant power applied to it (the armature has little thermal mass and doesn't have any cooling when the motor is not turning).

The motor should be able to move the arm OK, without overloading the motor.

And if you make a PID loop that does not have enough damping, it'll be running up and down all the time....

I'm going to suggest to our team that we put the modern control system on our 2007 robot, so they can learn how to program the arm.