A Hysteresis-Compensated Self-Sensing Scheme for Vanadium Dioxide-Coated Microactuators

Vanadium dioxide (VO₂)-coated silicon dioxide microactuators demonstrate fully reversible actuation, large bending and high energy density. To better utilize its actuation potential while minimizing the cost in obtaining sensory feedback, a novel composite hysteresis model is presented to obtain the deflection feedback based on the resistance measurement. In this model the deflection is obtained from the voltage value through a generalized Prandtl-Ishlinskii model, while the voltage in turn is calculated based on the resistance measurement through the analytical inverse of another generalized Prandtl-Ishlinskii model. For comparison purposes, a Preisach model and a polynomial model, respectively, are adopted to estimate the deflection based on resistance measurement directly. Experimental results show that, for a 550 μm long VO₂-based microactuator, the average absolute errors of the self-sensing schemes based on the composite model, the Preisach model, and the polynomial model are 0.554 μm, 1.232 μm, and 2.898 μm, respectively, over the deflection range of [−0.2, 102.9] μm. The composite model also shows advantages over the Preisach model in terms of the calculation time needed in deflection estimation. In addition, in separate verification experiments, the error resulted from the composite model-based self-sensing scheme is only 60% and 40 % of those under the schemes using the Preisach model and the polynomial model, respectively.