%0 Villanova Faculty Authorship
%A Elahinia, Mohammad H.
%E Ashrafiuon, Hashem.
%E Ahmadian, Mehdi.
%E Tan, Hanghao.
%D 2005
%G English
%T A Temperature-based Controller for a Shape Memory Alloy Actuator.
%U http://ezproxy.villanova.edu/login?url=https://digital.library.villanova.edu/Item/vudl:173861
%X This paper presents a robust nonlinear control that uses a state
variable estimator for control of a single degree of freedom rotary
manipulator actuated by shape memory alloy (SMA) wire. A
model for SMA actuated manipulator is presented. The model includes
nonlinear dynamics of the manipulator, a constitutive
model of the shape memory alloy, and the electrical and heat
transfer behavior of SMA wire. The current experimental setup
allows for the measurement of only one state variable which is the
angular position of the arm. Due to measurement difficulties, the
other three state variables, arm angular velocity and SMA wire
stress and temperature, cannot be directly measured. A modelbased
state estimator that works with noisy measurements is presented
based on the extended Kalman filter (EKF). This estimator
estimates the state vector at each time step and corrects its estimation
based on the angular position measurements. The estimator
is then used in a nonlinear and robust control algorithm based
on variable structure control (VSC). The VSC algorithm is a control
gain switching technique based on the arm angular position
(and velocity) feedback and EKF estimated SMA wire stress and
temperature. Using simulation it is shown that the state vector
estimates help reduce or avoid the undesirable and inefficient
overshoot problem in SMA one-way actuation
control.