Robust Control of VO ₂ -Coated Microbenders Using Self-Sensing Feedback

This paper presents the first studies on robust closed-loop deflection control of vanadium dioxide (VO2)-based microactuators using self-sensing. The deflection output of the microactuator is estimated by VO2resistance-based self-sensing through a high-order polynomial in order to eliminate the need for complicated external sensing mechanisms. An H∞robust controller is designed and implemented for precision deflection control, where uncertainties produced by the hysteresis between the deflection and the temperature input and the error in the self-sensing model are accommodated. The performance of the robust controller is tested in experiments under step and multisinusoidal reference inputs and compared to that of a proportional-integral-derivative (PID) controller. The robust controller outperforms the PID controller with 36% and 18% less tracking error for the step and multisinusoidal reference responses, respectively. To further show the robust performance of the H∞controller, a multisinusoidal reference tracking experiment with simulated white noise current signal is conducted, where the error using robust control is 34% less than that with PID control.