Active tugger line force control for single blade installation

Abstract

Single blade installation is one of the methods for installing large wind turbine blades at an o shore site. During this installation, each blade is lifted by the main crane from the deck of an installation vessel or a transportation barge with blade root approaching the hub. The blade root is then bolted to the hub. The nal mating phase is critical and requires high precision. Tugger lines from the crane boom are connected to the suspended blade to reduce pendulum motions. The entire process is typically completed without active tugger line force control. Due to wind-induced blade loads, strict requirement on installation precision, and the limitations imposed by the lifting equipment, the single blade installation operations are subject to weather constraints. Therefore, developing techniques to reduce the blade motions and consequently shorten the installation time is desired. In this paper, an active control scheme is proposed to control the tugger line forces acting on a blade during the nal installation stage before mating. A simpli ed 3 degree-of-freedom blade installation model is developed for the control design. An extended Kalman lter is used to estimate the blade motions and wind velocities. Feedback linearization and pole placement techniques are applied for the design of the controller. Simulations under turbulent wind conditions are conducted to verify the active control scheme, which e ectively reduces the blade root motions in the wind direction.

A Summary of the Recent Work at NTNU on Marine Operations Related to Installation of Offshore Wind Turbines

“…To verify the performance of the controller, time-domain simulations were conducted for turbulent wind conditions, using a 6DOF system with aerodynamic loads on the blade calculated similarly as in Zhao et al (2018). It was found that the proposed actively-controlled tugger line system works well as tested with the simulation verification model (Ren et al, 2017). A comparison of the blade translational motions at the root with and without the active tugger line control was shown in Figure 6.…”

“…Therefore, it is important to explicitly model these loads and estimate the induced responses as well as to control the blades during the final mating phase. In this section, we will summarize the work on blade installation analysis and control (Zhao et al, 2018;Verma et al, 2017;Ren et al, 2017), including the global response analysis and the local damage analysis due to contact/impact of the blade crosssections with surrounding structures.…”

“…This can be achieved by controlling the forces of the two tugger lines actively, as shown in Figure 4. A closed-loop scheme for active tugger line force control for single blade installation is developed by Ren et al (2017), considering a reduced model of the blade with 3DOF. An extended Kalman filter (EKF), a state feedback linearization and feedforward compensation algorithm, and pole placement techniques were applied to design the proportional-integralderivative controller, as shown in Figure 5.…”

A Comparative Study on the Dynamic Response of Three Semisubmersible Floating Offshore Wind Turbines

“…Based on the fundamental principles adopted to achieve static stability, a floating platform can be classified into three primary concepts: a semisubmersible (Semi), a Spar buoy and a Tension Leg Platform (TLP). Many researchers have made great efforts to investigate the difference in the dynamic responses of a variety of floating wind turbine systems [5][6][7].…”

Development and application of a simulator for offshore wind turbine blades installation

“…Research on intelligent marine operations are seeing increasing attention [5][6][7][8][9][10]. The typical objectives are to enhance the overall efficiency, ensure safety, broaden the operating window, and, ultimately, gain economic benefits.…”