高速高精度大行程纳米定位系统的线性自抗扰控制研究

High-speed and high-precision nanopositioning control is of great significance in many applications, as it is the key factor of imaging in Atomic Force Microscope, reading and writing data in high-storage-capacity hard-disk drives, manufacturing of integrated circuits. Most of the reported control algorithms, which were designed to improve the speed and precision of the nanopositioning systems, are model-based approaches. However, it’s hard to obtain accurate model of the system. Additionally, a variety of disturbances will also degrade the performance of the positioning systems. Both of the above issues will limit the applications of the model-based control approaches. Linear active disturbance rejection control (LADRC) has the advantages such as model-free, strong robust to disturbances, and easy to realize. This research project will make use of the advantages of LADRC to improve the precision of nanopositioning by overcoming hysteresis, which is one of the negative factors of reducing the performance of nanopositioning. And then the theoretical results for improving the precision will be concluded. The mechanism of improving the bandwidth and speed of the system by LADRC will be investigated. At the same time, the integral resonant control approach, which can suppress the resonant peak of the system, will be combined with LADRC to achieve a much faster speed. Theoretical analysis will be implemented to explore the compound high-speed positioning control law. In the end, the sensor noises, another negative factor of reducing the performance of nanopositioning systems, will be considered. Optimal design, which is able to guarantee both speed and precision of the nanopositioning systems, of LADRC will be obtained. The results of the project will break through the limit of resonant frequency and resonant peak, which are the adverse factors of reducing the speed of the nanopositioning systems; and clarify the noise effect on precision. It helps to design LADRC for high-speed, high-precision, large-range nanopositioning systems, and also provides a new idea in developing practical high-speed, high-precision control technique in nanopositioning.

高速高精度纳米定位控制是原子力显微镜成像、大容量硬盘信息存取、集成电路制造等诸多领域的关键技术。现有控制算法大多依据模型设计，然而精确模型难以获得，各种干扰亦使系统性能降低。因此，基于模型的控制策略提高定位性能的效果有限、工程应用困难。线性自抗扰控制具有对模型依赖小、抗干扰性强、易于工程实现的优势。借助线性自抗扰控制的优势，项目1）研究线性自抗扰控制补偿迟滞以提高定位精度的理论依据；2）研究线性自抗扰控制增大闭环带宽以提高定位速度的机制，并提出线性自抗扰与积分谐振的复合控制策略，探索复合控制获得更快定位速度的规律；3）研究噪声对定位精度的影响，提出兼顾定位速度和定位精度的线性自抗扰控制最优设计方法。项目成果将突破谐振频率和谐振峰值对定位速度的双重限制，揭示噪声对定位精度的影响规律，为高速高精度大行程纳米定位系统的线性自抗扰控制设计提供理论依据，为发展实用型高速高精度纳米定位控制提供新思路。

纳米技术是指对大小在100纳米或更小事物的认知和操控技术。纳米技术不仅指纳米材料制备技术，还包括纳米级测量、加工、控制等。在精密/超精密加工、原子力显微镜成像、大容量硬盘信息存取、集成电路制造等诸多领域，高速、高精度纳米定位控制技术的需求迫切。现有方法多为基于迟滞逆模型的前馈控制和基于迟滞逆模型的前馈反馈复合控制。然而，系统精确模型难以获得，各种扰动亦使系统性能降低。为提高定位系统性能，本项目借助自抗扰控制对模型依赖小、抗干扰能力强，易于工程实现的优势，研究了1) 线性自抗扰控制估计、补偿迟滞，以提高定位精度的理论依据；2) 纳米定位系统高性能（快速、准确）自抗扰控制设计及其参数优化方法；3) 噪声对定位精度的影响，以及兼顾定位速度和定位精度的自抗扰控制优化设计方法。通过上述研究，获得了提高定位精度和定位速度的自抗扰控制设计方法，包括ITAE最优的自抗扰控制二次优化设计方法；为降低量测噪声对系统性能的影响，而提出的实时调整观测器带宽、兼顾定位速度和定位精度的时变自抗扰控制。项目成果揭示了噪声对定位精度的影响规律，为高速高精度大行程纳米定位系统的自抗扰控制设计提供了理论依据，为发展实用型高速高精度纳米定位控制提供了新的思路。