A spatial linkage including an inboard gimbal plate that provides a ground
for the spatial linkage, an outboard gimbal plate, and three links that
couple the outboard gimbal plate to the inboard gimbal plate. Each link
has a longitudinal axis and two pivotal couplings disposed at opposite
ends of the longitudinal axis. Each link is pivotally coupled to the
outboard gimbal plate at a first end of the longitudinal axis and
pivotally coupled to the inboard gimbal plate at a second end of the
longitudinal axis opposite the first end. The pivotal couplings allow the
outboard gimbal plate to move relative to the inboard gimbal plate and
preventing relative rotation between the outboard gimbal plate and the
inboard gimbal plate.