Nonlinear system modeling and velocity feedback compensation for effective force testing

Jian Zhao, Carol Shield, Catharine French, Thomas Posbergh

Research output: Contribution to journalArticlepeer-review

36 Scopus citations


Effective force testing (EFT) is a test procedure that can be used to apply real-time earthquake loads to large-scale structural models. The implementation of the EFT method requires velocity feedback compensation for the actuators in order to apply forces accurately to test structures. Nonlinearities in the servosystem have a significant impact on the velocity feedback compensation and test results when large flow demands are present, which can be caused by large structural velocities and/or large forces applied to the test structure. This paper presents a nonlinear servosystem model, upon which a nonlinear compensation scheme is proposed. The model and compensation scheme are experimentally verified. The results indicate that the proposed model accurately describes the servosystem behavior, and with the nonlinear velocity feedback compensation, real-time dynamic testing can be conducted using the EFT method.

Original languageEnglish (US)
Pages (from-to)244-253
Number of pages10
JournalJournal of Engineering Mechanics
Issue number3
StatePublished - Mar 2005


  • Damping
  • Dynamic tests
  • Earthquakes
  • Simulation models
  • Structural response
  • Velocity


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