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Wind Turbine Shearography Robotic Inspection On-blade System (SheaRIOS)

Periodic Reporting for period 1 - SheaRIOS (Wind Turbine Shearography Robotic Inspection On-blade System (SheaRIOS))

Reporting period: 2018-01-01 to 2019-09-30

Wind energy is a fast growing industrial sector. As wind turbines are expected to work 90% of the time during a typical lifetime of 20 years, structural flaws are of great concern, particularly for blades. Repairing or replacing a blade is always difficult, especially for large wind turbine blades (WTB). The downtime of a wind turbine installation due to a blade failure usually lasts 4-6 days, longer than that due to electrical or mechanical failure within the nacelle. Cracks in the blades sometimes appear soon after manufacture. Defects also can be produced during transportation. Current inspection of wind turbine blade is mainly reliant on sending an engineer via rope access.

An ideal solution to this problem is to utilize a compact robot that can reach the blade and implement faster inspections on site. Shearography has long been recognised as a powerful inspection technique, and has found wide application in a range of industries including aerospace, automotive and shipbuilding sectors. However, conventional shearography still needs a relatively stable environment, thus it is difficult to use for on-site WTB inspections.

SheaRIOS is a solution for the WTB inspection that enables easier, faster and more accurate inspection utilizing robotics and shearography, a high-quality method that is brought outside the laboratory for the first time. A deployment platform will ascend on the wind turbine tower and deploy a work climber on the base of the blade. The climber will move along the blade by means of air-suction and carry out inspection with a shearography kit on a cantilever. The deployment platform will also act as the power and data link, while the system will be safely controlled by the ground.

The project has the following objectives:
To optimise the shearography system to detect subsurface defects within the WTB on-site
To design advanced image processing algorithms to post-processing the recorded images
To develop a compact crawler to carry and deploy the shearography kit along the WTB surface
To integrate the shearography kit and the carrier robot into the robotic platform
WP1: project management. Overall it is going well.

WP2: system specifications. Firstly, end-user requirements for WTB inspection were collated, which helped to refine the concept of the system. A system specification document was produced.

WP3: safety and standardisation procedures. A comprehensive risk analysis of the SheaRIOS system was carried out, which consisted a compilation of a method and an initial risk assessment.

WP4: shearography optimisation and algorithms development. For the shearography system, we have designed a specific optical set up for its integration with a compact VT610 crawler to inspect WTB on-site. This led to a new patent application (Ref 1912983.2) in September 2019.
Image processing algorithms were also develop to process the large number of speckle images and there corresponding fringe patterns. It consists of three steps: creating fringe patterns by image subtraction, image de-noising by filtering, and phase map calculation.
A series of validation tests were conducted to verify the inspection results from the shearography system. The comparable results demonstrated the defect detection capability of the shearography system.

WP5: adaptation of the robotic climber. A new frame for the crawler has been designed and fabricated. The platform is adaptable and optimized to the requirements of the shearography system. Since the shearography requires a stable working condition, it was determined that the motor on the crawler must be switched off. Hence two pneumatic cylinders are introduced to hold the crawler and the shearography system stable on the WTB surface during inspection.
The shearography was integrated, and a first field test on WTB un the ground was conducted in EDF on July 17, 2019.
Afterwards, the heat gun was integrated with the shearography on the crawler. A flexible shield is also developed to protect the shearography from daylight.
The control system is also developed, which enabled it to be operated remotely by an external PC through an Ethernet channel. This software enables the full access to functionalities of hardware components from a single control station connected to Ethernet channel.

WP6: optimisation of the robotic deployment platform. The original platform in the DashWin project. Apart from the overall frame, each part of the platform has been re-designed with significant changes in the vehicle, the ladder, and the deployment unit
For the vehicle part, the main chassis was kept unchanged and reused. The legs were completely redesigned. Also re-designed subsystems or components include the lifting subsystem, the wheel magnet pad, the operating principle, and the deployment unit, the fall protection unit, the deployment arm, and the crawler recovery mechanism.
To ensure the safety of the whole system, a fail-safe mechanism was also designed. This is to comply to relevant safety and industry standards. The different failure modes on the various components and subsystems of robotic platform were identified. The performance and integrity of the robotic platform on various fail-safe scenarios have also been assessed, which indicated that the system would be safe under reasonably foreseeable conditions.

WP7: System integration and preliminary tests. This WP started on Month-16 and will finish on Month-29. Although the progress is going well, there is not much to report this the first period.

WP8 has not started in this first period.

WP9: dissemination and exploitation. A web domain (www.shearios.com) was purchased by Dekra on behalf of the project consortium. A project website (www.shearios.com) was created, which comprises of both public and partner-only areas.
We have attended four conferences/exhibitions where we have promoted the project with various materials including a project poster, an exhibition material at a stand, an article in InDepthWind magazine in March 2019, and a flyer for the project.

WP10: ethics requirements, which relates to health and safety issues
The expected results are:
1. A advanced shearography system to detect subsurface defects within WTB on-site
2. A robotic system able to deploy the shearography onto a WTB to conduct inspection
3. Image processing algorithms for post-processing of the recorded images
4. A new operation procedure to carry out WTB inspection on a wind tower

The project will have the following impacts.
1. Increasing the market-readiness of robotics applications including in terms of technological validation outside the laboratory;
2. Increasing the market-readiness of robotics applications including in terms of sound operational and cost-benefit models
3. Lowering of market entry barriers of a business or regulatory nature.
4. Increasing industrial and commercial investment in Europe at a rate comparable with other global regions
5. Contributing to the faster growth of competitive small and mid-scale robotics companies in Europe
6. Addressing issues related to climate change or the environment, or bring other important benefits for society.
or the environment, or bring other important benefits for society.
First field test