Seismic test of least-input-energy control with ground velocity feedback for variable-stiffness isolation systems

Lyan Ywan Lu, Shih Yu Chu, Shih Wei Yeh, Lap Loi Chung

Research output: Contribution to journalArticlepeer-review

18 Citations (Scopus)


A variable-stiffness isolation system, whose isolation stiffness can be altered instantaneously in response to the seismic load, is able to provide better seismic protection for vibration-sensitive equipment or facilities than a conventional isolation system with a fixed stiffness. To determine its time-variant isolation stiffness, this system usually requires an effective on-line control law. In this study, a control strategy called the least input energy control (LIEC) is proposed for a general variable-stiffness isolation system. With the feedback of the ground velocity, at each time step the LIEC is able to determine the optimal isolation stiffness that minimizes the input seismic energy transmitted onto the isolated object. In order to evaluate its control performance, the LIEC was physically implemented on a leverage-type variable-stiffness isolation system, and tested in a seismic simulation test. The experimental response of the LIEC was then compared to the uncontrolled response, as well as the simulated responses of two semi-active control laws derived from the widely used LQR control and modal control. A comparison of the results demonstrates that, among all the control cases considered, the LIEC transmits the least seismic input energy to the isolated system, and thus has the best isolation performance. In addition, the test data also show that the LIEC requires the least control force and control energy. This indicates that the LIEC is also a very efficient control method for variable-stiffness isolation systems.

Original languageEnglish
Pages (from-to)767-784
Number of pages18
JournalJournal of Sound and Vibration
Issue number4
Publication statusPublished - 2012 Feb 13

All Science Journal Classification (ASJC) codes

  • Condensed Matter Physics
  • Mechanics of Materials
  • Acoustics and Ultrasonics
  • Mechanical Engineering


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