Climbing ring robot for inspection of offshore wind turbines

A rapid expansion of wind turbine farms for sustainable electric power production is planned in Europe by 2020. At least in the UK, these will largely be located offshore to meet growing concerns about the visual intrusiveness and noise generation producedby onshore based farms. The necessary structural integrity inspection of offshore wind turbine blades poses tremendous problems of access, danger to human operatives and costs in the event of blades having to be taken out of service and transported on shore forschedules inspections. For these reasons robotic in-situ blade inspection of offshore wind turbines has been proposed and micro/nano focus computed axial X ray tomography (MNCAT) has been identified as the optimal if not the only solution for identification of safety critical defects in the thickest blade sections. The weight of such an inspection system is very high, typically 200kg and typical cross sectional scanner dimensions of 1 m × 2 m to encircle as blade, clearly involve very high destabilizing moments to be countered by the deployment robot. The solution is a climbing ring robot completely encircling a turbine tower, typically 3 meter in diameter, to provide the necessary adhesion forces and anti-destabilizing force moments. Because of the size and thus development costs of such a huge robot the optimal design path is to prototype a small scale model. First results on such a model are described and from its performance the load carrying capabilities of a full scale version can be computed and the scale model can then berefined by 'reverse engineering' to guarantee that a full scale construction is able tomeet requirements. The key design innovation is that the adhesive forces between the robot and climbing surface a provided entirely by mechanical means rather than by usingthe usual methods of vacuum suction or magnetic force, making the system much cheaper andeasier to manipulate. Furthermore the design is entirely modular. Copyright © 2008 by World Scientific Publishing Co. Pte. Ltd

The Centre for Automated and Robotic Non-Destructive Testing

The Centre was established in 1992 to research and develop inspection robots and NDT techniques to [1,2]: • Bring automation to the NDT task to eliminate errors caused by human operators due to fatigue on jobs that require a great deal of inspection in difficult environmental conditions. • Improve defect detection by using the ability of robotics to improve sensor probe positioning accuracy and repeatability and use the programmable flexibility of robots to optimally deploy a wide variety of sensor probes and inspection techniques. • Reduce the cost of performing the inspection by using wall climbing and mobile robots that provide access to test sites that are remotely located on large structures and/or in hazardous environments and hence not easily accessible to humans. • Reduce costs substantially by performing in-service NDT with robotic deployment of sensor probes thereby eliminating outage costs and production losses. • Reducing capital equipment costs by developing compact multi-function inspection robots that can flexibly perform a variety of different NDT tasks on different sites. Thus the robots should be readily transportable between different sites, be able to move over floors, change surfaces and climb walls, ceilings and other structures of variable curvature whilst carrying a payload of NDT sensors that can scan test surfaces by deployment with multi-axis arms

Total Integrated Robotic Structural Inspection for Enhanced Aircraft Life and Safety

Aircraft life can be extended, safety standards and passenger confidence enhanced, and structural inspection costs dramatically reduced, by establishing at major airports specialised ‘Total Inspection Centres’ that would be open 24 hours a day. Aircraft would be flown to these centres. Here every relevant type of Non Destructive Testing (NDT) sensor would be deployed by multi-axis robots moving on Cartesian gantries to cover the wing, fuselage, tail and rudder. Each inspection would produce a defect map of 100% of the aircraft surface. This is very unreliable if done manually because of operator fatigue. A gantry robotic system has the advantage that very heavy NDT sensors such as X-ray tubes and SQUID magnetometers can be deployed in addition to all the more common sensors such as ultrasonic and Eddy current probe arrays. Acoustic emission monitoring of an entire airframe can be achieved with robotic scanning without the need for a vast and expensive array of sensors. This would be most useful for fuselage pressure testing. At present NDT of aircraft is carried out in many relatively small units attached to individual airports that cannot possibly afford the whole range of NDT equipment and robotic deployment facilities. A specialised centre can do so and in addition achieve complete data fusion of the results from different sensors

Climbing Robot Cell For Fast And Flexible Manufacture Of Large Scale Structures

This paper describes the specification stages of a project which seeks to modernise and take into the future the technology of the manufacture of large fixed welded structures such as box girder bridges, storage tanks, ships and other steel fabrications which arise on construction sites, in large chemical and foodstuff plants, on offshore oil platforms etc, bringing the world of fast and flexible manufacturing to areas were construction is presently carried out by traditional use of manual labour, scaffolding and cranes and the inconvenient delivery by road of large factory prefabricated components. The Project will achieve this by creating a transportable manufacturing cell (CROCELLS) consisting of a team of cooperating climbing robot work tools whose activities are coordinated and integrated through a central intelligence. Unlike factory based cells the robot work tools must be mobile and small so that they are able to climb over long distances, to great heights and over curved surfaces and surfaces with ridges or protusions such as nodal joints providing many technical robotics problems to be solved. Small robots have payload limitations but the essence of the cooperating robot concept is that large payloads of work tools can be achieved with small robots by distributing the payload over several robots. Each robot will be dedicated to a different task to optimise overall system performance, hence there could be be a surface profiler and navigator, welder, bolt and rivet placer, hot weld quality inspector, and cold weld inspector on separate platforms. The cell will be deployed through every stage of a product life cycle, during construction where the system will perform instant weld quality diagnostics and repairs, in service inspection and repair, and final lifetime assessment. The CROCELLS concept is described in detail and system specifications are given which arise from an analysis of the industrial problems to be solved in a first exploitation phase addressed to the business requirements of the end users in the project. Then the hardware and software Architecture optimized for these specifications is presented for a prototype system presently under construction. Presently large fabrications on construction sites suffer from long fabrication times prescribed by traditional methods. The proposed mobile manufacturing cell will greatly reduce these times with economic benefits estimated at 630 M€ per annum in save time and 1956M€ per annum equipment sales taking EU export markets into account, with data for the global market being typically a factor of 4 highe

A Set Of Mobile And Portable Robots For Nondestructive Inspection which Cover Critical Applications Across All The Key Use Industries

This paper describes the prototyping of some world first designs of mobile, portable robots which between them cover important safety critical applications across the spectrum of key civil and industrial engineering structures such as aircraft, ships, dams, nuclear power plant and storage tanks located in hazardous environments. The systems include novel features such as being able to climb over surfaces of complex contour to deploy the inspection sensors at each test point, ability to change surfaces, to work submerged in hazardous liquids and to scan large test areas. The rationale for using a robotic approach to NDT data acquisition is presented, given that it does involve some complexity in instrumentation design compared with current practice. A modular approach using as great a proportion of off-the-shelf components as possible has been used to greatly reduce the prototyping tim

Automated NDT of floating production storage oil tanks with a swimming and climbing robot

This paper describes the design and development of a prototype swimming and wall-climbing robot that gains access to internal tank wall and floor surfaces on Floating Production Storage Oil (FPSO) tanks for the purposes of carrying out Non-Destructive Testing (NDT) of welds while the tank is in-service and full of oil. A brief description is given of the inspection environment and the three NDT techniques (ultrasonic phased arrays, eddy current arrays, and Alternating Current Field Measurement ACFM arrays) that will be used to detect weld cracks and floor corrosion and pitting. © 2006 Springer-Verlag Berlin Heidelberg

Internal in-service inspection of the floor and walls of oil, petroleum, and chemical storage tanks with a mobile robot

The RobTank mobile robot can enter oil and chemical storage tanks through 300 mm or more diameter openings in the roof. It performs in-service inspection of the floor and walls while submerged in liquid thereby saving the cost of emptying, cleaning, and manually inspecting the tank. A navigation system keeps track of position and orientation within the tank. An array of ultrasonic wheel probes and two bulk-wave rotating probes look for corrosion thinning on the floor and walls up to half a metre ahead and under inaccessible floor areas. Obstacles such as drain sumps, heating coils, etc. are detected and avoided

Global warming and recurrent mass bleaching of corals

During 2015–2016, record temperatures triggered a pan-tropical episode of coral bleaching, the third global-scale event since mass bleaching was first documented in the 1980s. Here we examine how and why the severity of recurrent major bleaching events has varied at multiple scales, using aerial and underwater surveys of Australian reefs combined with satellite-derived sea surface temperatures. The distinctive geographic footprints of recurrent bleaching on the Great Barrier Reef in 1998, 2002 and 2016 were determined by the spatial pattern of sea temperatures in each year. Water quality and fishing pressure had minimal effect on the unprecedented bleaching in 2016, suggesting that local protection of reefs affords little or no resistance to extreme heat. Similarly, past exposure to bleaching in 1998 and 2002 did not lessen the severity of bleaching in 2016. Consequently, immediate global action to curb future warming is essential to secure a future for coral reefs

Deep reefs of the Great Barrier Reef offer limited thermal refuge during mass coral bleaching

Our rapidly warming climate is threatening coral reefs as thermal anomalies trigger mass coral bleaching events. Deep (or "mesophotic") coral reefs are hypothesised to act as major ecological refuges from mass bleaching, but empirical assessments are limited. We evaluated the potential of mesophotic reefs within the Great Barrier Reef (GBR) and adjacent Coral Sea to act as thermal refuges by characterising long-term temperature conditions and assessing impacts during the 2016 mass bleaching event. We found that summer upwelling initially provided thermal relief at upper mesophotic depths (40 m), but then subsided resulting in anomalously warm temperatures even at depth. Bleaching impacts on the deep reefs were severe (40% bleached and 6% dead colonies at 40 m) but significantly lower than at shallower depths (60-69% bleached and 8-12% dead at 5-25 m). While we confirm that deep reefs can offer refuge from thermal stress, we highlight important caveats in terms of the transient nature of the protection and their limited ability to provide broad ecological refuge.XL Catlin Seaview Survey; Waitt Foundation; XL Catlin Group; Underwater Earth; University of Queensland; ARC Discovery Early Career Researcher Award (DECRA) [DE160101433]; Portuguese Science and Technology Foundation (FCT) [SFRH/BPD/110285/2015]; Australian Research Council (ARC