Mobility Platform for Autonomous Offshore Wind Turbine Blade Repair

Maintenance and repair costs for offshore wind turbines have proven to be significantly higher than for land-based turbines, largely because of the difficulties involved in physical access to offshore turbines. As a result, there is increasing interest in developing autonomous mobile robots capable of performing maintenance tasks without the presence of a human operator onboard the turbine itself. It is anticipated that the use of autonomous robots to perform repair tasks will significantly reduce offshore wind repair costs and provide greater flexibility in the time periods when repairs can be performed. As a result, repair robots are seen as a critical tool in reducing the levelized cost of energy for offshore wind. The goal of this project is to develop an autonomous robot capable of attaching to the turbine blade and performing repairs without the presence of a human operator. Starting from a base station on a ship, the robot will fly to the turbine blade, attach to it, rappel to the repair location, and perform the repair task. It will then detach from the blade and land autonomously at its base station. The initial version of the robot will focus on leading edge repairs, but future versions may be capable of other types of repairs. The goal of the Phase I and II project is to develop and test a prototype of the mobility robot without the repair tooling attached. This will set the stage for further development of the system in which repair tooling and materials will be integrated to allow the robot to perform blade repairs. During Phase I, Persimia performed a trade study analysis and created a conceptual design for the blade repair robot. Sizing studies were performed and a simulation model was developed capturing vehicle flight dynamics and contact mechanics between the vehicle and blade. Key subsystems were designed and analyzed with respect to actuator force, torque, and power requirements. In addition, a set of risk reduction experiments was performed to determine performance of critical subsystems such as the docking anchor and vehicle thrusters. Overall, Phase I showed that the robot design is feasible and the vehicle can be built using largely off-the-shelf components. During Phase II, additional subsystems will be developed and a full-scale prototype of the robot will be constructed. The vehicle will be tested at an operating research-scale wind turbine, demonstrating the robot’s ability to autonomously fly to the blade, attach to it, rappel to a notional repair location, and detach from the blade and land. In addition, the project team will create a conceptual design for repair tooling integration in preparation for follow-on system development and eventual commercialization.