.ModelicaAdditions.MultiBody.Sensors.Sensor

Information

A sensor element determines the relative kinematic quantities
between frame_a and frame_b (= variables of superclass
Interact). It does not exert forces or torques.
The following relative variables can be determined:

  S_rel : Rotation matrix relating frame_a and frame_b, i.e. if
         hb is vector h resoved in frame_b and ha is vector h resolved
         in frame_a, hb = S_rel*ha.
  r_rela: Vector from the origin of frame_a to the origin of frame_b,
         resolved in frame_a.
  v_rela: (Translational) velocity of frame_b with respect to frame_a,
         resolved in frame_a: v_rela = der(r_rela)
  w_rela: Angular velocity of frame_b with respect to frame_a,
         resolved in frame_a: v_rela = vec( der(S_rel)'*S_rel )
  a_rela: (Translational) acceleration of frame_b with respect to
         frame_a, resolved in frame_a: a_rela = der( v_rela )
  z_rela: Angular acceleration of frame_b with respect to frame_a,
         resolved in frame_a: z_rela = der( w_rela )

If needed, all of the above quantities can also easily be resolved in
frame_b, according to  Xrelb = S_rel*Xrela . However note, that
 v_relb  is NOT  der(r_relb)  (v_relb=S_rel*v_rela; r_relb=S_rel*r_rela).