Electromechanically coupled beam models for stacked dielectric elastomer actuators

堆叠介电弹性体致动器的机电耦合梁模型

• 批准号: 426808054
• 负责人: Professorin Dr.-Ing. Sigrid Leyendecker
• 金额: --
• 依托单位: Lehrstuhl für Technische Dynamik
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2019
• 资助国家: 德国
• 起止时间: 2018-12-31 至 2022-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/426808054?language=en
• 关键词: Electromechanically; coupled; beam; models; stacked

The overall objective of this work is to provide computationally cost efficient but also accurate dynamic beam simulation models for dielectric elastomer actuators to be used in optimal control problems. Stacked dielectric elastomer actuators bear analogy to the behaviour of human muscles in terms of contracting in length direction when stimulated. They are suitable for point-by-point application of a force. Therefore, dielectric elastomers allow for a sophisticated, efficient and noiseless actuation of systems. However, the use of elastic actuators is also accompanied by new control challenges. Advanced control strategies need to avoid undesirable oscillations, bring the system as quickly as possible into its steady state and follow prescribed trajectories as closely as possible. Optimal control theory is used to avoid oscillations that are inherent with the elastic nature of dielectric actuators and to obtain optimised control trajectories. As the computational cost for solving optimal control problems is significantly affected by the number of model degrees of freedom, reduced and problem specific actuator models are superior to general but cost-intensive finite element models. In the first two years of the project, a cost-efficient beam actuator model that covers applications with stacked dielectric actuators is developed and tested. The cost-efficient dielectric actuator model is compared to an existing finite element based simulation framework as well as to an existing lumped model regarding simulation time and accuracy. Moreover, the beam actuator model is exemplarily coupled to a multibody system to investigate the behaviour of dielectric elastomer actuated systems. In the continuation of the project after the first two years, the coupling between the actuator model and an actuated structure is formulated in a structured and modular way that allows for arbitrarily complex scenarios and the cost-efficient beam model is used to solve optimal control problems of dielectric elastomer actuated systems. Numerical examples show the application of the simulation framework to simple biomechanical systems, such as an elbow joint, in order to investigate the requirements on dielectric elastomers to replace skeletal muscles. Small experiments addressing the identification of parameters and the validation of small simulation examples are planned.

这项工作的总体目标是提供计算成本有效，但也准确的动态梁模拟模型的介电弹性体致动器用于最优控制问题。堆叠的介电弹性体致动器在受到刺激时在长度方向上收缩方面类似于人类肌肉的行为。它们适合于逐点施加力。因此，介电弹性体允许系统的复杂、高效和无噪声的致动。然而，弹性致动器的使用也伴随着新的控制挑战。先进的控制策略需要避免不必要的振荡，使系统尽快进入稳定状态，并尽可能接近规定的轨迹。最优控制理论是用来避免振荡的电介质致动器的弹性性质是固有的，并获得优化的控制轨迹。由于求解最优控制问题的计算成本受模型自由度的影响很大，因此简化的和特定问题的致动器模型上级一般但成本密集的有限元模型。在该项目的前两年，开发和测试了一种具有成本效益的梁致动器模型，该模型涵盖了堆叠介质致动器的应用。具有成本效益的介电致动器模型相比，现有的有限元为基础的仿真框架，以及现有的集总模型的仿真时间和精度。此外，梁致动器模型是示例性地耦合到一个多体系统，以调查的行为介电弹性体致动系统。在前两年之后的项目的延续中，致动器模型和致动结构之间的耦合以结构化和模块化的方式制定，允许任意复杂的场景和具有成本效益的梁模型用于解决介电弹性体致动系统的最优控制问题。数值例子显示了模拟框架的应用程序，以简单的生物力学系统，如肘关节，为了调查的要求，介电弹性体，以取代骨骼肌。小型实验解决的参数识别和验证的小型模拟实例的计划。