"Improving the speed, accuracy, and movement range of piezoelectric scanners in scanning probe microscopy"

压电扫描器在扫描探针显微镜中起着至关重要的作用。 尽管压电陶瓷具有使其成为精确定位的最佳材料的所有品质，但它们在产生的运动中远非理想。 SPM最终成为经济上可行的纳米制造工具的能力依赖于压电致动器在不损害其定位精度和可重复性的情况下高速移动并通过大范围的能力。 目前，这两方面的性能都受到压电陶瓷线性范围的限制。 此外，现有的压电致动器在被命令保持恒定位置时在低速下易受噪声影响。 由于外部干扰、压电蠕变和热漂移而产生的噪声是低速时位置不准确的主要原因。 为了解决压电扫描器的性能问题，我们过去在识别问题和形成解决方案方面取得了一些进展。 最重要的是，我们已经建立了一个微观力学模型，可以捕捉极化域切换过程。 因此，它可以预测扫描仪的非线性行为，在一个更普遍，完整和准确的方式。 它采用可以与物理测量相关联的物理参数。 提出的研究的目的是把我们现有的工作到一个新的水平，即联合收割机的模型与控制器的设计，以更好地控制扫描仪的运动。 具体目标包括：1）开发一种降阶模型，该模型可以弥合完整的微观力学模型和具有真实的时间可处理性的模型之间的差距。 2)发展一种自感知策略以辅助真实的时间模型参数估计。3)开发了一种逆控制技术来补偿材料的非线性，以提高位置精度。4)开发主动阻尼技术以控制扫描器在高扫描速率下的振动。5)提高隔振器的消声质量。 最后，性能的改善将通过实验台上的实验进行验证。

Piezoelectric scanner plays a vital role in the scanning probe microscope (SPM). Despite all the qualities piezoceramics have that make them the best materials for precision positioning, they are far from being ideal in the motion they generate. The ability of an SPM to eventually become an economically viable nano-fabrication tool relies on the ability of the piezoelectric actuator to move at high speed and through a large range without compromising its positioning accuracy and repeatability. At present, both aspects of performance are limited by the linearity range of piezoceramics. In addition, existing piezoelectric actuators are susceptible to noise at low speed when they are commanded to hold a constant position. Noise due to external disturbance, piezoelectic creep and thermal drift are major causes of position inaccuracy at low speeds. To address the performance issues of a piezoelectric scanner, we have made some progress in the past in identifying problems and forming solutions. Most importantly, we have constructed a micromechanics model that can capture the polarization domain switching process. Consequently, it can predict the nonlinear behavior of the scanner in a more general, complete, and accurate manner. It employs physical parameters that can be correlated to physical measurements. The objective of the proposed research is to take our existing work to the next level, that is, to combine the model with controller design to better control the scanner movement. Specific goals include: 1) Developing a reduced order model that can bridge the gap between a full micromechanics model and a model with real time tractability. 2) Developing a self-sensing strategy to assist real time model parameter estimation. 3) Developing an inversion control technique to compensate for the material nonlinearity to achieve improved position accuracy. 4) Developing an active damping technique to control the scanner vibration at high scanning rate. 5) Improving the quality of noise cancellation in the vibration isolator. Finally, performance improvement will be verified through experiments on a test-bed.