Development of a Novel Stewart Motion Platform for Wind Tunnel Testing of Floating Wind Turbines

The utilization of offshore floating wind turbines is anticipated as one of the most sustainable sources of renewable energy. The research on these floating wind turbines requires highly sophisticated and established testing facilities that can produce simultaneous aerodynamic and hydrodynamic loadings on the floating turbines. However, due to the scaling mismatch of the airflow, water-flow, and wave profiles in most of the current test facilities, the laboratory testing of floating wind turbines has been very challenging. The primary focus of the present study is to develop a novel method of testing floating wind turbines in regular wind tunnel facilities. In this paper, we aim to develop a new experimental approach of simulating the floating turbine motions induced by ocean waves using Stewart motion platforms. These motion platforms can generate six degrees of freedom and mimic the motions of linear translations and axial rotations found in a multitude of floating devices. In designing the Stewart motion platform, kinematics was used with rotational actuators in translating the platform and developing a wave generation program for general motion displacement. In addition, multiple types of wave formations and their displacements are generated based on a systematic calculation and coordinate conversions of each individual actuator. The motion platform is capable of translating to nearly 5 cm linearly and reaching a maximum rotation of 15 degrees in both directions individually and simultaneously. The prototype platform model in this paper is used for turbine models about 30 cm in height for testing in a large-scale atmospheric wind tunnel facility. This work can be further developed by harnessing machine learning capabilities of data collection from research performed in wave tanks or field testing. Subsequently, in considering the effects of a floater, further research implementations of a floater’s response are dependent on the properties and behavior of a buoyant structure which leads to a closer accurate model of a floating wind turbine in the ocean.