Frequency domain method for real-time detection of oscillations

Girish Chowdhary, Sriram Srinivasan, Eric N. Johnson

Research output: Contribution to journalArticlepeer-review


Because of the growing interest in real-time stability monitoring, there is a need for online methods that can detect off-nominal behavior in control systems.Therefore, we present a realtime frequency domain method for detecting oscillations in control systems. The method uses recursive Fourier transform for representing the measured time-domain signal in frequency domain. Oscillations are then detected by monitoring the norm of the Fourier coefficients over a time window of prespecified size across a range of frequencies that represent offnominal behavior for the plant. The method is computationally efficient and requires little memory, and hence suitable for online application. The feasibility of using this method for a real-time detection of oscillation is demonstrated on the Georgia Tech Twinstar Unmanned Aerial System.

Original languageEnglish (US)
Pages (from-to)42-52
Number of pages11
JournalJournal of Aerospace Computing, Information and Communication
Issue number2
StatePublished - Feb 2011
Externally publishedYes

ASJC Scopus subject areas

  • Aerospace Engineering
  • Computer Science Applications
  • Electrical and Electronic Engineering


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