@latekvo@IanPritchard Looks like it's positional control via tension. By varying the power going to the voice coil, he controls oppositional force to an elastic element. Final position being the result of opposing forces.
@Toenes This is commonly done in many places. Same thing with nut or egg allergies, take as much as you can until it stops hurting. Knew a Japanese guy who overcame severe egg allergies that way.