Adjust the auto-collimator and the reflector, and ensure that the auto-collimator can obtain the reflection image within the entire scope of measurement. Place the reflector on the initial measurement position of the guide rail, record the angle of component Y of the auto-collimator, move the reflector, and measure the whole guide rail according to the intercept b initially set. The angle of component Y of the auto-collimator reflects the change in height of the current position of the guide rail in respect of the initial measurement position, manifested by the initially set slope of each segment in respect of the initial position.
Thus, the change in height of the current position in respect of the initial reference point can be calculated.
ΔY’ is the displacement of the location of reticle cross image
f’ is the focal length of the auto-collimator
Δθy is the angle of the component Y of the photoelectric auto-collimator
The straightness variation curve of the whole guide rail can be plotted according to the least square method or the minimum zone method and other fitting principles.