A control mechanism pins an optical fiber assembly on and off gimbal and
between gimbals to route the assembly from an off-gimbal optical source
across the gimbal axis/axes to an on-gimbal optical element so that the
fiber assembly moves with the rotation of the gimbals. To accommodate a
relatively large range of motion, the control mechanism is suitably
configured to route the fiber assembly in a "U-shaped" loop with one end
pinned off-gimbal in a stationary guide track and the other end pinned
on-gimbal point in a rotating guide track so that the loose fiber
assembly is constrained in the concentric tracks on and off gimbal. As
the gimbal rotates, the loop seats onto one guiding track and peels off
of the other guiding track while always maintaining its U shape. To
accommodate a relatively small range of motion in other gimbal
configurations, the control mechanism is suitably configured to pin one
end of the fiber assembly off-gimbal and pass the fiber assembly directly
over the gimbal where it is pinned on the other side of the gimbal. In a
multi-gimbal pointer, the fiber assembly preferably exhibits different
mechanical stresses as it crosses the different gimbals.