Linear Axis Testbed - Rail Degradation Experiment 01

In this study, a rail of a linear axis testbed was intentionally degraded to
various levels, affecting the carriage motion, which can be deduced with either an
inertial measurement unit (IMU) or a laser- based reference system. The rail was
degraded over a 10-cm-long region. Thus, the two trucks that move on the rail interact
with this region of the rail, changing the translational and angular error motions of
the carriage. To mechanically simulate spalling, a handheld grinder was used to wear the
surface of the raceway groove of the rail. The degradation zone length was increased
incrementally by about 5.4 mm from its nominal state of no degradation (Stage 1) to its
final state of significant degradation with a length of about 75 mm (Stage 15). For each
stage of degradation, micrometer measurements were taken of the degradation zone, and
IMU and laser-based reference data were also collected. For each stage, fifty (50) runs
of IMU data were collected bidirectionally at slow (0.02 m/s), moderate (0.1 m/s), and
fast (0.5 m/s) axis speeds over a travel range of 322 mm, following the method described
in Vogl et al. (https://www.nist.gov/publications/diagnostics-geometric-
performance-machine-tool-linear-axes). The axis position from the motor encoder was also
collected simultaneously during each motion of the linear axis. Afterwards, ten (10)
runs of laser-based reference data were collected bidirectionally at finite positions of
travel, specifically every 1 mm between travel positions 1 mm and 321 mm.