NONLINEAR CONTROL OF A SHAPE
MEMORY ALLOY ACTUATED MANIPULATOR
Mohammad H. Elahinia, August 2001
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Abstract
This thesis presents a nonlinear, robust control
algorithm for accurate positioning of a single degree of freedom rotary manipulator
actuated by Shape Memory Alloy (SMA). A model for SMA actuated manipulator is
presented. The model includes nonlinear dynamics of the manipulator,
constitutive model of Shape Memory Alloy, and electrical and heat transfer
behavior of SMA wire. This model is used for open and closed loop motion
simulations of the manipulator. Experiments are presented that show results
similar to both closed and open loop simulation results. Due to modeling
uncertainty and nonlinear behavior of the system classic control methods such
as PID control are not able to present fast and accurate performance. Hence a
nonlinear, robust control algorithm is presented based on Variable Structure
Control. This algorithm is a control gain switching technique based on the weighted
average of position and velocity feedbacks. This method has been designed
through simulation and tested experimentally. Results show fast, accurate and
robust performance of the control system. Computer simulation and
experimental results for different stabilization and tracking situation are
also presented.
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Copyright 2001 Villanova University Department of Mechanical Engineering
Last updated 07/28/01 MHE