Stress Based Control of a Single-Degree-of-Freedom SMA Actuated Arm
VIRGINIA POLYTECHNIC INST AND STATE UNIV BLACKSBURG DEPT OF MECHANICAL ENGINEERING
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In this paper a nonlinear stress-based controller is designed to position a single-degree-of-freedom shape memory alloy SMA actuated manipulator. A three part model was constructed based on the dynamicskinematics of the arm, the thermomechanical behavior of SMAs and a heat transfer model consisting of electrical heating and natural convection. A variable structure controller is designed to calculate a desiredness based on position error. The desired stress is compared with the actual stress which is computed using a Kalman filter. The stress error is then used for control via a proportional-integral PI controller. Numerical simulations are performed to investigate tracking performance and robustness. The results demonstrate that the controller design is highly accurate in tracking both stationary and time-varying input signals.
- Metallurgy and Metallography