Nonlinear stress-based control of a rotary SMA-actuated manipulator

Mohammad H. Elahinia, T. Michael Seigler, Donald J. Leo, Mehdi Ahmadian

Research output: Contribution to journalArticlepeer-review

48 Scopus citations


In this paper a nonlinear stress-based controller is designed to position a singledegree-of-freedom shape memory alloy (SMA) actuated manipulator. A three-part model was constructed based on the dynamics/kinematics of the arm, the thermomechanical behavior of SMAs, and an assumed heat transfer model consisting of electrical heating and natural convection. Both sliding mode control and inverse dynamics control are used to calculate a desired stress, based on the position error. The desired stress is compared with the actual stress which is computed using an Extended Kalman Filter. The stress error is then used for control via a proportional-integral controller. Numerical simulations are performed to investigate tracking performance as well as other issues such as robustness. The results demonstrate that the variable structure controller designs are highly accurate in tracking both stationary and variable input signals.

Original languageEnglish
Pages (from-to)495-508
Number of pages14
JournalJournal of Intelligent Material Systems and Structures
Issue number6
StatePublished - Jun 2004


  • Control
  • Modeling
  • Nonlinear control
  • Robot
  • Shape memory alloy
  • Sliding mode control

ASJC Scopus subject areas

  • General Materials Science
  • Mechanical Engineering


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