Nonlinear Flexure Control using Shape Memory Alloy Actuators

This paper presents a nonlinear control scheme for deflection control of a flexible beam using Shape Memory Alloy (SMA) actuators. These actuators posses interesting properties in terms of force generation capacity, possibility of miniaturization, and power consumption. However, their use in precision applications is hampered by undesirable characteristics such as nonlinearities, hysteresis,extreme temperature dependencies, and slow response. By taking into account the nonlinear andthermal characteristics, a control scheme based on partial feedback linearization is developedin order to regulate the forces exerted by a differential SMA actuator pair attached to a flexible beam.A Lyapunov stability analysis is furnished and the developed control scheme is tested experimentally on a laboratory testbed.