Joint Input and State Estimation of a Scaled Wind Turbine Model: An Experimental Study

Abstract

Structural health monitoring (SHM) has gained recognition in civil engineering and is now a well-established technique. Recently, it has received considerable research attention in the application in Wind turbine (WT) structures. A complete sensing system could provide comprehensive information about the structure during long-term operations. In this study, a 1:50 scaled WT model of the 5-MW reference WT presented by the National Renewable Energy Laboratory (NREL) was designed and manufactured, and a comprehensive SHM sensing system was installed on the WT tower. The system included accelerometers, strain gauges, and as well as a camera system that integrated digital image correlation (DIC) technology and binocular stereo vision technology. By employing the joint input and state estimation (JISE) technique, both the unmonitored structural responses and the unknown interface input were estimated. The study found that blade rotation exerted significant effects on the WT tower responses. The feasibility of WT SHM using the camera system was also validated and discussed in the research. These findings establish a basis for future dynamic analysis of WT structures using the estimated responses and input. Moreover, the study results present a cost-effective approach for monitoring the structural health of WT systems.