National Instruments NI-Motion - Manual (Page 86)

Chapter 6 Arc Moves
NI-Motion User Manual 6-8 ni.com
Figure 6-7. Changing Yaw by Rotating the Z Axis
In the transformed X'Y'Z' space, the 3D arc is reduced to a simpler 2D arc.
The 3D arc is defined as a 2D circular arc in the X'Y' plane of a transformed
vector space X'Y'Z'. This transformed vector space, X'Y'Z', is defined in
orientation only, with no absolute position offset. Its orientation is relative
to the XYZ vector space, and is defined in terms of pitch and yaw angles.
When rotating through the pitch angle, the Y and Y' axes stay aligned with
each other while the X'Z' plane rotates around them. When rotating through
the yaw angle, the Y' axis never leaves the original XY plane, as the
newly-defined X'Y'Z' vector space rotates around the original Z-axis.
The radius, start angle, and travel angle parameters also apply to a spherical
arc that defines the arc in two dimensions.
Z
X
Y