Deflection control of a flexible beam using shape memory alloy actuators

This paper presents a nonlinear control scheme for deflection control of a flexible beam system using shape memory alloy (SMA) smart actuators. Due to their interesting properties such as force generation capacity, possibility of miniaturization, and power consumption, these devices have been gaining increased popularity in the past few years. However, SMA actuators possess undesirable characteristics such as nonlinearities, hysteresis, extreme temperature dependences, and slow response that make them difficult to use in precision applications. By taking into account the nonlinear and thermal characteristics, a control scheme is developed in order to regulate the force exerted by an SMA actuator attached to a flexible beam. The control scheme is based on input–output linearization of the nonlinear system. The control goal is to regulate the force exerted by the SMA actuator to a desired value. The internal dynamics of the system is derived and it is shown that this dynamics can be stabilized by proper choice of the controller gain matrices.