Difference between angular velocity vectors (WXYZ)
The WXYZ measure returns the difference between the angular velocity vector of marker i and the angular velocity vector of marker j resolved in the coordinate system of marker k.
Format
WXYZ(i[,j][,k])
Arguments
Applied To Marker (i) | The marker whose velocity is being measured. |
Applied From Marker (j) | The marker with respect to which the angular velocity is being measured. If j is not specified, it defaults to the global origin. Specify j = 0 if you want to use this default, and then specify k. |
About Marker (k) | The marker in whose coordinate system the angular velocity vector is being expressed. If not specified, k defaults to the global coordinate system. |
Extended Definition
Mathematically, WXYZ is calculated as:
where:
■
is the angular velocity vector of marker i in ground.
is the angular velocity vector of marker i in ground.■
is the angular velocity vector of marker j in ground.
is the angular velocity vector of marker j in ground.■
is the unit vector along the x-axis of marker k.
is the unit vector along the x-axis of marker k.■
is the unit vector along the y-axis of marker k.
is the unit vector along the y-axis of marker k.■
is the unit vector along the z-axis of marker k.
is the unit vector along the z-axis of marker k.Examples
A vector expression for angular velocity might be used directly in the definition of a vector torque element:
VTORQUE/3, I=310, JFLOAT=9911, RM=310,
, TXYZ = -6.*WXYZ(310,9900,310)