Modeling and Inverse Compensation of Nonmonotonic Hysteresis in VO $_2$-Coated Microactuators
Modeling and Inverse Compensation of Nonmonotonic Hysteresis in VO $_2$-Coated Microactuators
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DOI：
10.1109/tmech.2013.2250989
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发表时间：
2014-04
期刊：
影响因子：
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通讯作者：
Jun Zhang;E. Merced;N. Sepúlveda;Xiaobo Tan
中科院分区：
文献类型：
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作者：
Jun Zhang;E. Merced;N. Sepúlveda;Xiaobo Tan
二氧化钒 (VO2) 会经历热诱导的固相转变，可用于驱动目的。当温度在相变过程中变化时，VO2 涂层的硅悬臂梁会表现出突然的曲率变化。与许多其他智能材料中观察到的单调滞后现象不同，VO2 执行器的曲率-温度滞后是非单调的，这是由于与材料相变相关的竞争机制以及形成双层悬臂梁的材料的不同热膨胀系数所致。受基础物理学的启发，提出了一种结合了单调 Preisach 磁滞算子和二次算子的非单调磁滞新模型。提出了一种约束最小二乘方案用于模型辨识，并提出了一种有效的逆控制方案用于磁滞补偿。出于比较目的，考虑具有符号密度函数和单值多项式模型的 Preisach 算子。实验结果表明，对于 300 μm 长的执行器，在 [ -104, 1846] m-1 的驱动曲率范围内，所提出的模型、带符号的 Preisach 算子和多项式近似的最大建模误差分别为 46.8、80.3 和 483 m-1。此外，所提出的反演方案的最大跟踪误差和均方根误差仅为基于多项式反演方案的10%左右。
Vanadium dioxide ( VO2) undergoes a thermally induced solid-to-solid phase transition, which can be exploited for actuation purposes. VO2-coated silicon cantilevers demonstrate abrupt curvature changes when their temperature is varied across the phase transition. Unlike the monotonic hysteresis phenomena observed in many other smart materials, the curvature-temperature hysteresis of VO2 actuators is nonmonotonic due to competing mechanisms associated with the material's phase transition and the different thermal expansion coefficients of the materials that form the bilayered cantilever. Motivated by the underlying physics, a novel model for the nonmonotonic hysteresis that combines a monotonic Preisach hysteresis operator and a quadratic operator is presented. A constrained least-squares scheme is proposed for model identification, and an effective inverse control scheme is presented for hysteresis compensation. For comparison purposes, a Preisach operator with a signed density function and a single-valued polynomial model are considered. Experimental results show that, for a 300- μm -long actuator, the largest modeling errors with the proposed model, the signed Preisach operator, and the polynomial approximation are 46.8, 80.3, and 483 m-1, respectively, over the actuated curvature range of [ -104, 1846] m-1. In addition, both the largest tracking error and root-mean-square error under the proposed inversion scheme are only around 10% of those under the polynomial-based inversion scheme.