Experimental enriched beam model for robust simulation of soft material robotic systems

最近的一个研究主题是软材料机器人，它能够执行几乎不受限制的、连续的变形，并为驱动、控制和传感提供新的机会。它们能够适应障碍物，安全地处理脆弱的物体，并轻松改变其运动行为，这使得它们在医疗保健、人机交互和救援行动中的应用前景非常广阔。然而，由于机器人的弹性结构、复杂的材料行为和连续的大变形，为了描述它们的特性和变形行为，丰富的模型是必不可少的。因此，本研究项目的目标是开发一种适用于任意软材料机器人的稳健数学模型，该模型涵盖了与周围环境的相互作用和动力学效应。为提高计算效率，将机器人的结构简化为空间中的柔性材料曲线，采用有希望的Cosserat梁方法。关于模型的适用性和有效性，将在研究项目中解决以下研究问题：1.复杂软材料机器人在运行中需要捕捉哪些影响，以及如何用Cosserat梁方法适当地处理这些影响？2.软材料机器人的驱动与模型中的相关参数之间是什么关系，以及叠加是否有效？3.由于机器人结构简化，如何在Cosserat梁模型中包含接触力和外部载荷以覆盖局部相互作用现象？4.Cosserat梁模型与更详细地描述机器人结构的模型相比，误差有多大？为了回答这些研究问题，将对制造的气动驱动软材料机器人进行数值研究和实验分析。制造的机器人在变形行为(弯曲、扭曲、伸长)和结构的复杂性方面有所不同。基本试验有助于确定驱动引起的变形与相关模型参数之间的相关性。此外，对机器人在外加载荷和接触下的行为的额外分析有助于建立Cosserat梁方法。在整个项目中，将检验模型的有效性，并将结果与相应的实验进行比较。为了明确模型的精度和局限性，将Cosserat梁方法与更详细的几何有限元模型进行比较，作为本项目的结果，将建立任意软材料机器人的参数化梁模型并应用于特殊原型。此外，数值工作和实验分析为更全面地了解软材料机器人及其在操作过程中的特殊特性和行为做出了宝贵的贡献。

A recent subject of research are soft material robots that are able to perform nearly unrestricted, continuous deformations and facilitates new opportunities of actuation, control and sensing. Their ability to adapt to obstacles, safely handle fragile objects and easily change their motion behavior makes them very promising for applications in healthcare, human-robot interactions and rescue operations. However, to describe their characteristics and deformation behavior, enriched models are indispensable, which account for the elastic structure, the complex material behavior and the continuous and large deformations of the robot. Hence, the objective of this research project is the development of a robust mathematical model that is valid for arbitrary soft material robots and covers interactions with the surrounding and dynamical effects. For computational efficiency, the promising Cosserat beam approach will be adopted, for which the structure of the robot is reduced to a flexible material curve in space. With regard to the models applicability and validity, the following research questions will be addressed within the research project:1. Which effects of complex soft material robots in operation needs to be captured and how can they appropriately be addressed by the Cosserat beam approach?2. What is the correlation between the actuation of the soft material robot and the related parameter in the model, and is a superposition valid?3. Due to the simplified robot structure, how do contact forces and external loads need to be included in the Cosserat beam model to cover local interaction phenomena? 4. How significant is the error of the Cosserat beam model compared to models which represent the robot structure in more detail?To answer these research questions, numerical investigations and experimental analyses on fabricated pneumatic actuated soft material robots will be conducted. The fabricated robots differ in their deformation behavior (bending, twist, elongation) and in the complexity of their structure. Basic tests help to identify the correlation between the actuation induced deformation and the related model parameters. Furthermore, additional analyzes of the robot’s behavior under applied loads and contacts help to establish the Cosserat beam approach. Throughout the project, the model’s validity will be examined and results compared to corresponding experiments. To clarify the accuracy and limits of the model, the Cosserat beam approach will be compared to geometrical more detailed finite element models.As a result of this project, a parameterized beam model for arbitrary soft material robots will be established and applied to special prototypes. Furthermore, the numerical work and experimental analyses constitute a valuable contribution to a more holistic understanding of soft material robots, their special characteristics and behavior during operation.