inherently dangerous hence, the advent of remote
visual inspection (RVI).
RVI employs the use of remotely operated
camera systems including videoprobes, tube
cameras, robotic crawlers, pan-tilt-zoom (PTZ)
cameras, uncrewed aerial systems (UASs/drones),
and submersible remotely operated vehicles (ROVs).
The remote nature of the data capture, sophistica-
tion of the tooling, and skill of the inspector drives
safe, efficient, and cost-effective inspections in haz-
ardous, inhospitable, and inaccessible plant systems
and components. Moreover, many of these inspec-
tion instruments may be deployed with a wide array
of payloads delivering manipulators, cleaning appa-
ratuses, and varying sensor technologies to encom-
pass a broader range of mission parameters.
Modern robotic crawlers are exceptionally
well-suited for a wide variety of inspection tasks.
As indicated in Figure 1, the assets, applications,
industries, and methodologies can be extensive and
far-reaching. These tools are becoming increasingly
capable of capturing a myriad of inspection data
FOR VISUAL TESTING
J U L Y 2 0 2 4 • M A T E R I A L S E V A L U A T I O N 35

while providing a significant reduction in periph-
eral inspection costs such as scaffolding, insulation
removal, and confined space entry. The reduction or,
oftentimes, elimination of these supporting activities
also optimizes the safety profile of the inspection by
reducing labor and minimizing high-risk activities.
This article will examine common crawler platforms,
deployment considerations, and offer a unique use
case for review.
Crawler Platforms
Crawler platforms generally consist of a camera
control unit (CCU), crawler body, camera(s), and a
cable/cable reel. The CCU enables remote operation
of system features such as crawler travel direction
and speed, as well as camera articulation and oper-
ation. Furthermore, the CCU may provide critical
feedback to the operator, such as travel distance and
camera orientation. The CCU may also enable data
Inside tank/
boiler/dome
Outside tank/
boiler/dome
Inside/outside turbine
blade/tower
Dams, building,
bridges, etc.
Steam/gas turbine
and generators
Outside pipe/
above ground Inside pipe
Asset/Application Tanks Boilers Vessels Pipelines Piping Containment
dome
Industrial
equipment
Civil/industrial
structures
Wind
turbines
Method
Radiographic Gas detection Infrared Lidar
Visual/camera Electromagnetic Ultrasonic Other Optical
Environment
New construction
Hazardous Elevated temperature Dirty Electrically classified Wet
Out of service In-service
Cleanliness requirement
Inspection
criteria
Internal company
procedures
Other SDO/
agency
ASME
Section V
Acceptance
criteria ASME NBIC API DOT/PHMSA Other
End result Quality data
Videos, pictures, measurements, models
Crawler platform(s)
ground/non-climber
or climber
Medium size climbers Large size climbers Small size climbers
Climbers (tethered and non-tethered)
Self-propelled
Magnetic Suction
Medium size crawlers Large size crawlers Small size crawlers
Crawlers (tethered and non-tethered)
Differential pressure
Magnetic Tracks/wheels/legs
Figure 1. Crawlers for inspection by asset/application from ASME MUS-2.
FEATURE
|
ROBOTICCRAWLERS
36
M A T E R I A L S E V A L U A T I O N • J U L Y 2 0 2 4
CREDIT:
ASME,
USED
WITH
PERMISSION