The 3 signals of the force connector contain force and torque.
The first and second signal are interpreted as the x- and y-coordinates of
a force and the third is torque, acting at the frame connector
to which frame_b of this component is attached.
Note that torque is a scalar quantity, which is exerted perpendicular
to the x-y plane.
An example of this model is given in the following figure:
The parameter resolveInFrame defines in which frame the input force shall be resolved.
Developed 2010 at the DLR Institute of System Dynamics and Control