The SMART Project (Scanning, Monitoring, Analysing, Repair and Transportation) has been funded by the Federal Ministry of Economic Affairs and Energy in Germany (BMWi) since August 2014.
The aim of the SMART research project is the development of a climbing service platform for wind turbines. Using a work booth, the rotor blade is encased at a desired section, so that fault detection and maintenance can be carried out independent of weather conditions. In the work booth workers can move around freely and work at great height, without the risk of vertigo. In particular, it is possible to utilise both measurement and repair technologies, autonomously or teleoperatively, within the robust work booth, which helps avoid accidents with people beforehand.
In combination with a trend monitoring system, the analysis of the measured data can be automated while the availability of wind turbines can be increased in a sustainable manner.
With due regard to the requirements of the industry, great importance is attached to logistics and a quick operational readiness of the SMART platform. This has a huge effect on economic efficiency.
The project has been funded by the BMWi with the following total funding sum:
Phase 1: approximately € 1.8 million for the project duration of 18 months
Phase 2: approximately € 3.4 million for the project duration of 30 months
Work booth for all-year maintenance of wind turbines, independent of weather conditions. Additionally, the SMART concept provides a platform for the following potential applications:
In phase 1, the SMART climbing system, with the respective payload, on a lab scale of 1:3, was developed and tested, its climbing capacity validated. The specifics of the certification aspects were observed. For the certification, the climbing suitability for wind turbines matters the most, i.e. the SMART robot must not cause any damage to the tower structure or tower surface during the climbing operation. With the demonstration of the climbing SMART, this objective has been fully achieved. The research findings were presented to the PTJ on 1 December, 2015.
During the first phase, the focus was on the chain climbing system which was developed and built on a scale of 1:3. This measure served as a feasibility study in order to determine the functionality of the chain climbing system during the "up and down motion" at the tower. The operating principle of the climbing process is based on static friction. The necessary contact pressure force on the chain runners is generated by the clamping mechanism. The concept for the clamping mechanism is guided by the principle of the "Nuremberg Scissors". At the same time, evidence was provided that the contact pressure force was clearly below the admissible load limit of the wind turbine tower structure.
During phase 2, the 1:3 demonstrator from phase 1 is scaled to a 1:1 prototype and developed further. In this phase, the work booth for the maintenance of the rotor blades and two long load beams, which are mounted to the climbing system, are developed. Additionally, the interior of the work booth is prepared for the work on the rotor blades; peripheral devices as well as a robotics system are integrated.
As described above, in this phase of the project, the prototype is developed. The SMART installation requires a multifunctional transport and mounting aid. Optimised logistics and a quick, cost-efficient installation of SMART on a wind turbine are essential requirements from the industry.
A man-carrying concept for the SMART climbing platform has top priority. In parallel, a teleoperative, robot-assisted extension is developed which can operate remotely controlled and at height in numerous applications, as, for example, during test exercises with thermographic or ultrasonic measuring systems. The ever-increasing number of safety regulations for manned maintenance are the reason for this parallel development.
Demonstration models on a scale of 1:20 were made to provide the basis for the development of the demonstrator on a scale of 1:3. The models are fully functional and allow for the practical examination of the kinematic connections. Thereby, the simulation results can be validated at an early development stage. The model for the belt-climbing principle showed the negative influence of belt stretch: after each clamping and release cycle, the belt-climbing robot moved downwards. As a consequence, the theoretical lift of the climbing mechanism was shortened.
With the help of a second model, propelled by chain chassis, the drive control could be developed and experience with continuous climbing acquired. Due to the various loads, micro-sliding or slippage, especially in connection with steering motions, the uniform motion of the chain chassis leads to tension building up in the rigid connection, the size and type of which were to be examined by means of the demonstrator.
Further iterations of the demonstration models pertain to an optimisation of the drive and the electronics, so that fault susceptibility is reduced and a swift and uncomplicated presentation at trade fairs or during lectures is made possible. Furthermore, the boom system and the work booth were reviewed and revised in order to demonstrate the latest developments.
The demonstrator has a total of ten chain drives which are extremely compact and light in weight in order to reduce the weight forces while simultaneously increasing the load-carrying capacity. Harmonic Drive drives, which can supply high torque, were utilised to overcome starting torque as well as compensate for flexing. For precise drive control, high-resolution absolute encoders with servo amplifiers are employed. This way, a synchronous speed of the individual engines can be ensured during the demonstrator phase in order to allow for a climb up the wind turbine in as straight a line as possible. At the same time, examinations regarding skid steering are possible: generating a turn around the tower axis through a variation of both rotational speeds of one chain drive at a time. Verification of the created kinematic models are effected by means of a self-made tracking system on the basis of the ar_track_alvar algorithms which were implemented with the Robot Operating System ROS.
After verification of the kinematic model, the forces are simulated in the model. For an experimental test of the dynamic model, the demonstrator was equipped with several six-axis force or momentum sensors which make it possible to record the chronological sequence of the loads. In due consideration of the experimental results and after alignment with the kinematic and dynamic model, the created models are to serve the purpose of scaling the SMART climbing robot to a 1:1 prototype in phase 2 of the project.
How can wind turbines be maintained more efficiently? One answer to this question could be: with the help of a climbing service platform which is being developed at the FH Aachen within the framework of the SMART (Scanning, Monitoring, Analysing, Repair and Transportation) project. Among other things, one objective is a considerable reduction of the time required for maintenances and, thereby, of the standstill of the wind turbines; moreover, maintenance shall be carried out independent of weather conditions.
At the Hannover Trade Fair, the SMART Project team presented the chassis and a demonstrator of the climbing service platform at the joint exhibition stand of the state of North Rhine-Westphalia. It wasn't just the visitors to the fair who came to the research assistant in charge, Mohsen Bagheri, looking for information on the climbing robot. Dr. Thomas Grünewald, State Secretary at the Ministerium für Innovation, Wissenschaft und Forschung des Landes NRW (Ministry of Innovation, Science and Research of North Rhine-Westphalia), and Karl-Uwe Bütof, department head at the Ministerium für Wirtschaft, Energie, Industrie, Mittelstand und Handwerk NRW (Ministry of Economic Affairs, Energy, Industry, SMEs and Trade of North Rhine-Westphalia) were very impressed with the work of the FH Aachen scientists.
The research team has found a way to build a service platform that climbs up a wind turbine tower along the outside. In a work booth attached to the platform, people can move around freely and work at great height, without the risk of vertigo. Moreover, measurement and repair technologies can be carried out teleoperatively from the ground.
In combination with a trend monitoring system, the analysis of the measured data can be automated while the availability of wind turbines can be increased in a sustainable manner. With due regard to the requirements of the industry, great importance is attached to logistics and a quick operational readiness of the SMART platform.
Funding of the SMART Project
In August 2014, the SMART project was given the go-ahead; it was initiated with the help of the EurA Network InTeWIND. The aim of the SMART research project is the development of a climbing service platform for wind turbines. The project is now in its second funding phase. For the duration of 30 months, funding amounts to € 3.4 million. During the first phase, which was funded by the Federal Ministry of Economic Affairs and Energy (BMWi) with € 1.8 million, scientists already built a climbing robot demonstrator on a scale of 1:3.
The supervising professors are Dr. Peter Dahmann from the Faculty of Aerospace Engineering and Dr. Stephan Kallweit from the Faculty of Mechanical Engineering and Mechatronics. Mohsen Bagheri and Josef Schleupen work as supervising research assistants for the project.
You can watch the demonstrator on a scale of 1:3 on YouTube: SMART Demonstrator
Besuchen Sie den SMART-Kletterroboter auf dem Landesgemeinschaftsstand B30 des Landes Nordrhein-Westfalen in Halle 2 auf der diesjährigen Hannover Messe (24. - 28. April).
Climbing Service Platform for the Maintenance of Rotor Blades on Wind Turbines, Independent of Weather Conditions - SMART
Published on 16 November 2016 at the AKIDA in Aachen Technology Centre
Der SMART-Kletterroboter wurde sehr erfolgreich auf dem Stand C28 des Bundesministeriums für Wirtschaft und Energie (BMWi) in Halle 2 auf der diesjährigen Hannover Messe (25. - 29. April 2016) vorgestellt.
Von den einzigartigen Möglichkeiten des SMART konnten sich auch die Wissenschaftsministerin des Landes Nordrhein-Westfalen Svenja Schulze sowie der Parlamentarische Staatssekretär Herr Uwe Beckmeyer beim Messebesuch am Stand des BMWi überzeugen.
Interview with the inventor and deputy project manager Mr Mohsen Bagheri
FH Aachen University of Applied Sciences
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