Feasibility study on a strain based deflection monitoring system for wind turbine blades

Kyunghyun Lee, Aya Aihara, Ganbayar Puntsagdash, Takayuki Kawaguchi, Hiraku Sakamoto, Masaaki Okuma

Research output: Contribution to journalArticlepeer-review

29 Citations (Scopus)


The bending stiffness of the wind turbine blades has decreased due to the trend of wind turbine upsizing. Consequently, the risk of blades breakage by hitting the tower has increased. In order to prevent such incidents, this study proposes a deflection monitoring system that can be installed to already operating wind turbine's blades. The monitoring system is composed of an estimation algorithm to detect blade deflection and a wireless sensor network as a hardware equipment. As for the estimation method for blade deflection, a strain-based estimation algorithm and an objective function for optimal sensor arrangement are proposed. Strain-based estimation algorithm is using a linear correlation between strain and deflections, which can be expressed in a form of a transformation matrix. The objective function includes the terms of strain sensitivity and condition number of the transformation matrix between strain and deflection. In order to calculate the objective function, a simplified experimental model of the blade is constructed by interpolating the mode shape of a blade from modal testing. The interpolation method is effective considering a practical use to operating wind turbines' blades since it is not necessary to establish a finite element model of a blade. On the other hand, a sensor network with wireless connection with an open source hardware is developed. It is installed to a 300 W scale wind turbine and vibration of the blade on operation is investigated.

Original languageEnglish
Pages (from-to)117-129
Number of pages13
JournalMechanical Systems and Signal Processing
Publication statusPublished - 2017 Jan 1
Externally publishedYes


  • Deflection monitoring
  • Strain monitoring
  • Vibration monitoring
  • Wind energy
  • Wind turbine blades

ASJC Scopus subject areas

  • Control and Systems Engineering
  • Signal Processing
  • Civil and Structural Engineering
  • Aerospace Engineering
  • Mechanical Engineering
  • Computer Science Applications


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