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Active Control of Structural Non-stationary Response Using Improved Hilbert Huang Method

Momeni Massouleh, Hassan | 2019

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  1. Type of Document: Ph.D. Dissertation
  2. Language: Farsi
  3. Document No: 52146 (45)
  4. University: Sharif University of Technology
  5. Department: Aerospace Engineering
  6. Advisor(s): Hosseini Kordkheili, Ali; Mohammad Navazi, Hossein
  7. Abstract:
  8. Adaptive vibration control of a structure under different condition of exciting forces or structural response is the main scope of this research.Using a combination of the pole placement and online Empirical Mode Decomposition (EMD) methods, a new algorithm is proposed for adaptive active control of structural vibration. For this purpose, by structural response which is evaluated from Hilbert-Huang Transform (HHT) and using prior knowledge for corresponding conditions, proper and optimum control forces are applied to structure. Hence, error sources of EMD method in the HHT such as end effects error, mode mixing problem and decomposition resolution are being studied. A modified method based on combination of auto regressive model and mirror method is developed to reduce end effects error. Also, in order to avoid from mode mixing problem a bandwidth EMD scheme is developed to effectively improve the results with lower computational efforts. The comparison between EMD and proposed online-EMD reveals that signal decomposition resolution is increased for closely spaced frequencies in online EMD method. After that, instantaneous frequency extraction is investigated as well as the identification of the noise modes from main intrinsic mode functions. Finally, estimated instantaneous properties which extracted from HHT are utilized to improve the pole placement method as an adaptive active control technique. In the end of each section, the efficiency and effectiveness of the proposed methods are shown by analytical and experimental case studies
  9. Keywords:
  10. Empirical Modes Decomposition (EMD)Method ; Online Signal Processing ; Hilbert-Huang Transform ; Instantaneous Frequency Measurment ; Adaptive Vibrations Control

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