Algorithm 4 Pitch–Yaw step climbing

Require: robot is set longitudinally parallel to the stair; Ensure: the creation of a ground-level foundation for the robot;  Raise nth module;  Raise ($n-1$)th module;  Place nth module on top of the step;  do      Place ($n-1$)th module on top of the step;      $n\leftarrow n-1$  while $n>6$             ▹ Number of stable foundation modules  Undo ground level foundation;  Create a new foundation on top of the step;  do      Place ($n-1$)th module on top of the step;  while  $n>1$  Undo the foundation on top of the step; Ensure: the robot is correctly positioned;