Any site maintenance of wind turbines is complicated by
their remote location and height. This means that remote
condition monitoring takes on even greater importance
of not requiring working at height, and
not requiring favourable weather to be
carried out.
Drone inspection can
provide a similar service
to ground-based
inspection, with
enhanced image clarity
resulting from greater
freedom in positioning
the camera.
Once a defect has
been detected using a
remote method, manual
Inspection is often required as a
follow-up to assess the extent of damage.
It provides the best observations of
defects. Detailed photos of defects can
be inspected by engineers after the rope
access work. Other inspection methods
Because of the challenges to manual
access to blades, other methods have
been developed. For inspection,
there are typically three
options. First, groundbased
inspection
uses large telephoto
lenses and ultra-high
de nition imaging.
Special software can be
used to stitch together
approximately 1,100
images to give a complete
view of a blade. The position
and dimensions of defects can
also be measured using this software.
Regular ground-based inspections can
be carried out to generate a record of
blade condition over time. Groundbased
inspection has the advantages
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POWER GENERATION
also used include laser scanning to create
3D images, and conductivity to determine
continuity of lightning protection
systems.
Once a defect has been identi ed as
requiring repair, the blade is normally
manually accessed again to ll and/or sand
down the a ected area.
Robot developer Aerones has
developed a number of robotic solutions
for inspection, cleaning and repair to be
carried out without manual access. These
robots have a stabilising tripod frame
suspended from a cable system which
carries a robot arm. This enables the
robot to access both the blades and the
tower of a wind
Autumn 2020 www.operationsengineer.org.uk 73
There’s a robot for that
One year on from the launch of MIMRee, Multi-Platform
Inspection, Maintenance and Repair in Extreme Environments,
project partners report breakthroughs in their quest to
demonstrate an end-to-end autonomous inspection and repair
mission to o shore wind farms.
Awarded a £4.2 million grant from Innovate UK, the project is
one of o shore wind’s most ambitious robotics project to date.
The end-game is demonstration of an autonomous system
capable of planning its own operational missions to o shore
wind farms, whereby a ‘mother ship’ will scan moving turbine
blades on approach, then launch teams of inspection drones
carrying blade crawlers for forensic inspection and repair of
damaged blades.
The list of successes in solving technological challenges in
the rst year of the two-year project suggests that the vision
might well be feasible, according to project participants.
First, the Thales imaging system has achieved blur-free
images of moving wind turbine blades at the O shore
Renewable Energy (ORE) Catapult’s Levenmouth
Demonstration Turbine o the coast of Fife. Scanning blades
for defects, without stopping turbines for days at a time, is
considered a game-changer for wind farm operations.
Second, MIMRee mission planning software developed by
Prof. Sara Bernardini of Royal Holloway University of London
has been integrated with the Thales vessel and the inspection
drones
developed by
a team from Manchester
and Bristol Universities. The drones have successfully
coordinated launch, recovery and navigation from the vessel.
One of the aims of the project is to demonstrate an
integrated inspect-and-repair system for wind turbine blades,
using the BladeBUG robot (pictured), which has recently
demonstrated its walking abilities on a variety of blade surfaces
at ORE Catapult’s National Renewable Energy Centre. Again,
multiple technologies have been shown to work. First, an
autonomous repair arm developed by Dr Sina Sareh’s team
at the Royal College of Art Robotics Laboratory can rapidly
switch between modules for cleaning, sanding and top-coating
damaged areas of blades, providing real-time feedback
visualisation and human-in-the-loop remote operation of
repair tasks via a user-interface system, the team says.
Second, plant Integrity has produced the blade crawler’s
non-destructive testing (NDT) payload. The module uses a
precision scanner for exact measurement of defects under a
wide variety of ambient light conditions. Third, an electronic
skin, called Wootzkin, patented by robotics company,
Wootzano, will enable the robot to determine the surface
conditions of the blade, helping the robot to walk in an extreme
environment.
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