Inversion-Based Nanopositioning Control For Ultra-high-speed Scanning Probe Microscopy

在GOALI项目中，将开发一套基于系统反演理论的新型控制技术，以显著提高大成像尺寸和大样品粗糙度的扫描探针显微镜（SPM）的操作速度。为了实现横向扫描过程中的高速精确定位，研究了一种基于反演的迭代控制（IIC）算法，以同时补偿压电作动器的非线性滞后和振动动力学效应。为了研究IIC算法的收敛性，我们将探索一个由preisach滞后模型和线性动力学模型组成的级联模型。为了实现afm探针在垂直轴上的精确定位，将开发一种新型的二自由度前馈-反馈控制器，使基于逆的前馈控制器和鲁棒反馈控制器协同工作。此外，通过最小化输出能量来减少输出振荡的最佳输出转换技术将与IIC算法相结合，以实现高速附着力测量。开发的控制技术将通过与PI在国际滑联的同事合作，在一系列科学和工程研究中加以实施和评价。发展超高速SPM与国家纳米技术计划确定的纳米技术（“纳米尺度仪器和计量”）的重大挑战领域相一致。超高速SPM将彻底改变SPM在许多领域的应用，包括但不限于生物医学成像（例如，研究快速生物过程，如活细胞运动）、分析化学（例如，单分子反应的实时监测）、纳米制造（用于实际用途的纳米器件的高通量制造）和生物测定。该项目的教育和推广活动将通过开放实验室参观和指导大一本科生，激发女性/少数民族学生在早期对科学/工程领域的兴趣。与GOALI项目的工业合作伙伴Veeco的合作将通过暑期实习增强研究生的行业经验，并加速将开发的技术转移到行业。

In this GOALI project, a suite of novel control techniques based on the system-inversion theory will be developed to significantly increase the operation speed of scanning probe microscope (SPM) with large imaging size and large sample asperities. To achieve high-speed precision positioning during lateral scanning, an inversion-based iterative control (IIC) algorithm will be studied to simultaneously compensate-for the nonlinear hysteresis and the vibrational dynamics effects of piezo actuators. A cascade model consisting of the Preisach-based hysteresis model followed by the linear dynamics will be explored to investigate the convergence of the IIC algorithm. To achieve precision positioning of the AFM-probe in the vertical-axis, a novel two degree-of-freedom feedforward-feedback controller will be developed to enable the inversion-based feedforward controller and the robust feedback controller to work in concert. Furthermore, an optimal output transition technique that reduces output oscillations by minimizing the output-energy will be integrated with the IIC algorithm to achieve high-speed adhesion force measurement. The developed control techniques will be implemented and evaluated in a set of scientific and engineering studies, through the collaborations with the PI's colleagues at ISU.Developing ultra-high-speed SPM resonates with the grand challenge areas of nanotechnology ("Nanoscale Instrumentation and Metrology") identified by the National Nanotechnology Initiative. Ultra-high-speed SPM will revolutionize the use of SPM in numerous areas, including, but not limited to, biomedical imaging (e.g., study of rapid biological processes such as living cell locomotion), analytical chemistry (e.g., real-time monitoring of single-molecule reactions), nanomanufacturing (high-throughput manufacturing of nanodevices for practical uses), and bioassays. The proposed education and outreach activities of the project will stimulate women/minority students' interests in science/engineering areas at their early age through the Open-Lab tours and mentoring freshman undergraduates. The collaboration with Veeco, the industrial partner in this GOALI project, will enhance the graduate students' industry experience through summer internships, and accelerate the transfer of the developed technology to the industry.