41
Z ? = tribometer defined
horizontal direction
Y
t <^ = tribometer defined
X vertical direction
- -
^k
T' TI = 'cosp ^'sinp
^k = ^'=cosp +t'sinp
counterface misalignment roll angle (3, rotation about I axis
l ,- T'=tr=oso- ^i'ino
k = 1koso +J"sino
counterface misalignment pitch angle (, rotation about 1'axis
Figure 4-5 Potential misalignment angles in positioning counterface stub into
reciprocating stage.
The counterface sample starts aligned with the tribometer measurements axis. Unit
vectors located on the counterface, 1, j ,and k are respectively parallel to the X
(horizontal), Y, and Z (vertical) measurement axes of the tribometer. In positioning the
counterface stub into the reciprocating stage a first possible rotation error, the roll angle,
3, about the j axis may occur, resulting in new counterface defined coordinates i, j'
and k'. A second possible rotation error, the pitch angle, (, about the ? axis results in
the final counterface orientation coordinate system, i ", )" and k". The equations
relating the actual counterface sample coordinate directions (i", j" and k") and the