The model shown
here is still in an incomplete state and not physiologically correct, but
it illustrates nicely the development of the system from the initial 2-D
bicycle.
It is a model of a trunk fixed to the ground with an arm and a skiing
pole attached. The model drives the motion of the hand so that the pole
performs a cyclic motion.
The representation of the body segments is rather primitive and
requires some explanation: the centers of gravity (CG) of each segment are
represented by the yellow boxes. From the CG, the system generates a line
connected to each of the points defined on each segment, for instance for
muscle attachments. This means that the yellow lines in the model are not
skeleton representations but merely a way to illustrate rigid bodies.
The model is equipped with 52 individual muscles.
The muscle model of this stage could not handle muscles that wrap over
bones, so all muscles are approximated by straight lines. This is a
significant approximation, particularly w.r.t. the muscles spanning the
trunk.