A novel three degree-of-freedom microactuator based on thin-film lead-zirconate-titanate (PZT) is described with its detailed structural model. Its central rectangular-shaped mirror platform, also referred to as the stage, is actuated by four symmetric PZT bending legs such that each leg provides vertical translation for one corner of the stage. It has been developed to support real-time in vivo vertical cross-sectional imaging with a dual axes confocal endomicroscope for early cancer detection, having large displacements in three axes (z, θx, θy) and a relatively high bandwidth in the z-axis direction. Prototype microactuators closely meet the performance requirements for this application; in the out-of-plane (z-axis) direction, it has shown more than 177 μm of displacement and about 84 Hz of structural natural frequency, when two diagonal legs are actuated at 14V. With all four legs, another prototype of the same design with lighter stage mass has achieved more than 430 μm of out-of-plane displacement at 15V and about 200 Hz of bandwidth. The former design has shown approximately 6.4° and 2.9° of stage tilting about the x-axis and y-axis, respectively, at 14V. This paper also presents a modeling technique that uses experimental data to account for the effects of fabrication uncertainties in residual stress and structural dimensions. The presented model predicts the static motion of the stage within an average absolute error of 14.6 μm, which approaches the desired imaging resolution, 5 μm, and also reasonably anticipates the structural dynamic behavior of the stage. The refined model will support development of a future trajectory tracking controller for the system.

中文翻译：

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一种具有大平面外位移的三自由度薄膜 PZT 驱动微致动器

描述了一种基于薄膜锆钛酸铅 (PZT) 的新型三自由度微致动器及其详细的结构模型。其中央矩形镜台，也称为舞台，由四个对称的 PZT 弯曲腿驱动，每个腿为舞台的一个角提供垂直平移。它已被开发用于支持实时体内垂直横截面成像，双轴共聚焦内窥镜用于早期癌症检测，在三个轴（z、θx、θy）上具有大位移，在 z 轴上具有相对较高的带宽方向。原型微执行器非常符合该应用的性能要求；在面外（z 轴）方向，它显示出超过 177 μm 的位移和大约 84 Hz 的结构固有频率，当两个对角线脚在 14V 下驱动时。对于所有四个支腿，具有更轻载物台质量的相同设计的另一个原型在 15V 和大约 200 Hz 的带宽下实现了超过 430 μm 的平面外位移。前一种设计显示，在 14V 时，载物台分别围绕 x 轴和 y 轴倾斜大约 6.4° 和 2.9°。本文还介绍了一种建模技术，该技术使用实验数据来解释残余应力和结构尺寸中制造不确定性的影响。所提出的模型预测舞台的静态运动在 14.6 μm 的平均绝对误差内，接近所需的成像分辨率 5 μm，并且还合理地预测了舞台的结构动态行为。