Multistage Multistable Actuation System with scalable stroke, range and force capability based on cooperative electrostatic actuators (MUST ACT)

在电极之间的距离非常小的情况下，静电致动器提供高能量密度和作用力。然而，在这些条件下，由于拉入，驱动范围非常有限。对于传感器应用(陀螺仪：初级振荡的激励、加速计：力反馈)，这些限制并不重要，因为在这里，几乎无质量的系统只需要极低的激励范围(µm)和极低的力(µN)。然而，就目前的技术水平而言，静电驱动不能用于“宏观”应用所需的大范围和大作用力。最先进的是英寸蜗杆电机，它通过两个夹紧致动器与一个“移动”致动器的协作功能，提供大行程和大作用力。然而，这些致动器系统相对较大(最小的多层芯片约为2x2x2 mm³)，不能用单片微制造来制造。本项目的动机是研究基于大量可用标准硅工艺制造的小型化、可提供大行程(Cm)和大作用力(N)的协作静电致动器来实现静电驱动的英寸蜗杆状致动器系统的科学基础。为了实现这一最终愿景，需要更好地理解基于微系统的执行器系统的原理、限制和边界条件，这些执行器系统由大量小型化、多级、多稳定和协作的静电执行器构建，并提供可扩展的步长、总射程和力，所有这些都可以在几个数量级上进行缩放。一个具体的科学问题是非线性静电力对单个、分布式、多稳态和协作子执行器以及通过耦合的整个执行器系统的机械稳定性的影响。这里的基本问题是，为了一个仍然稳定的整个系统，可以集成多少这样的协作和级联单驱动器，小型化、精度和可控性的极限是什么(例如，由所有驱动器中的制造元件的粗糙度和几何偏差造成的)。此外，需要对每个静电致动器(空闲和活动状态)所提供的固有电容传感的限制和交叉耦合进行系统的研究。此外，还需要了解使用标准硅基微米和纳米技术工艺的小型化和可生产性，以及机械和电气系统行为的限制。除了同质集成概念(仅限于静电致动器)，还将研究非均质系统(例如，结合静电和压电致动)，这需要一个通用的和参数的系统描述和基本设计规则，特别是考虑到稳定性。作为方法，将使用有限元和SIMULINK模拟、微纳技术和高分辨率表征技术。

At very small distances between the electrodes electrostatic actuators provide high energy density and forces. However, at these conditions actuation range is very limited due to pull-in. For sensor applications (gyros: actuation of primary oscillation, accelerometers: force feedback) these limitations are not really important as here only very low actuation ranges (µm) and very low forces (µN) are needed for the almost massless systems. However, as state of the art, electrostatic actuation cannot be used for large range and forces needed for „macro“ applications. State of the art are inch-worm-motors which provide both, large stroke and force, by cooperative function of two clamping actuators with a “moving” actuator. However, these actuator systems are relatively large (smallest multilayer chip ca. 2x2x2 mm³) and cannot be fabricated with monolithical microfabrication.The motivation of this project is to investigate the scientific fundamentals for the realization of electrostatically driven inch-worm like actuator systems based on a large amount of cooperative electrostatic actuators which are miniaturized, can be fabricated by standard Si-technology and which provide both, large stroke (cm) and large forces (N). For that final vision a better understanding of principles, limitations and boundary conditions are needed for microsystem based actuator systems which are built from a huge amount of miniaturized, multistage, multistable and cooperative electrostatic actuators and which provide scalable step size, total range and forces which all can be scaled over several orders of magnitude. A specific scientific question is the influence of non-linear electrostatic force on mechanical stability of each single, distributed multistable and cooperative sub-actuator and of the total actuator system by coupling. Basic questions here are how many of these cooperative and cascaded single actuators can be integrated for a still stable total system and what are the limits for miniaturization, precision and controllability (e.g. caused by roughness and geometrical deviation of fabricated elements within all the actuators). Additionally, a systematic investigation of limitation and cross-coupling for the inherent capacitive sensing provided by each electrostatic actuator (both, in idle and active state) is needed. Further, understanding of miniaturization and producibility using standard Si-based micro- and nanotechnological processes and of the limits of mechanical and electrical system behavior is needed. Besides homogenous integration concepts (only electrostatic actuators), also heterogeneous systems (e.g. combining electrostatic and piezoelectric actuation) will be investigated which needs a general and parametric system description and fundamental design rules for such a system, especially considering stability. As methods, FEM- and Simulink simulation, micro- und nanotechnology and high resolution characterization techniques will be used.