Robust control of VO2-coated microactuators based on self-sensing feedback

A novel self-sensing and robust control technique is presented for a vanadium dioxide (VO₂)-coated silicon (Si) microactuator. The deflection output of the microactuator is estimated by resistance-based self-sensing through a high-order polynomial model in order to eliminate the need for complicated sensing mechanisms. To accommodate the uncertainties produced by the hysteresis between the deflection and the temperature input, and the error in the self-sensing model, an H_∞ robust controller is designed and implemented for deflection control. The performance of the robust controller is tested in experiments under step and sinusoidal reference inputs and compared to that of a proportional-integral-derivative (PID) controller. The H_∞ controller outperforms the PID controller with 31% and 43% less root-mean-square-error for the step and sinusoidal references, respectively, while maintaining 3.1% less control effort for the latter.