Additional Info glossary
Radial Runout( E XYC
)
Radial runout or radial error is defined as the positiondependent lateral error motion of a rotary stage perpendicular to the axis of rotation( see α in Figure 5b). The radial runout
E XYC is a combined error in the X and Y direction when rotating around the Z-axis.
Wobble( E ABC
)
Wobble is the position-dependent angular misalignment of the real axis of motion relative to its ideal axis. Wobble E ABC is a combined tilt deviation around the X and Y-axes when rotating around Z that effects a radial runout that scales with height( see E XYZ
( z) Figure 5b).
Radial runout and wobble are often cyclic in nature and are caused by the imperfect nature of mechanical components. They are defined for one full rotation( 360 °) and do not include a static offset( eccentricity or tilt) or surface errors of the rotating table. Note: ASME B. 5.64 specifically addresses linear positioners. Since radial runout and wobble are phenomena associated with rotary positioners, we have adjusted the nomenclature for radial errors accordingly. The second subscript ' r ' denotes the rotational axis( rotation around the Z-axis).
|
+ Y
+ B( rotY)
|
+ C( rotZ) |
+ X
+ A( rotX)
|
+ B( rotY) |
+ A( rotX) |
Figure 4a and 4b: Right-handed coordinate system with rotational axes on the corresponding linear axes for a linear positioner( a) and a rotatory positioner( b) |
+ Y
+ Z
E CC
+ X
+ Z
E XYC
( Z)
E CX
|
|
E ZX |
|
Figure 5a and 5b: Nomenclature of errors in the various axes for a linear motion( a) and for a rotatory motion( b) |
E YX |
E XX |
E XYC |