  This paper proposes a comprehensive framework designed for the autonomous
inspection of complex environments, with a specific focus on multi-tiered
settings such as distillation column trays. Leveraging quadruped robots
equipped with roller arms, and through the use of onboard perception, we
integrate essential motion components including: locomotion, safe and dynamic
transitions between trays, and intermediate motions that bridge a variety of
motion primitives. Given the slippery and confined nature of column trays, it
is critical to ensure safety of the robot during inspection, therefore we
employ a safety filter and footstep re-planning based upon control barrier
function representations of the environment. Our framework integrates all
system components into a state machine encoding the developed safety-critical
planning and control elements to guarantee safety-critical autonomy, enabling
autonomous and safe navigation and inspection of distillation columns.
Experimental validation in an environment, consisting of industrial-grade
chemical distillation trays, highlights the effectiveness of our multi-layered
architecture.
