CAREER: A Design Methodology for Bio-Inspired Soft Mechanical Systems

这项学院早期职业发展(Career)计划拨款将开创一个系统的综合、分析和制造框架，以实现软机械系统。软机械系统是静态和动态结构实施例，其不包含由金属或塑料制成的刚性部件、诸如马达之类的常规致动器或诸如接头和联轴器之类的接口。它们是由可伸缩的皮肤、组织状的附属物、纤维和液体组成的，灵感来自大约90%缺乏僵硬脊椎的自然界动物物种，如章鱼手臂。这些系统的独特之处在于，它们既灵活又坚固，足以承受较大的载荷。遗憾的是，到目前为止，这些系统还没有得到广泛应用，因为目前还没有一个系统的设计框架来指导它们的物理实现。该奖项支持实现这样一种设计框架的基础研究，在该框架中，软机械系统可以通过具有预定属性的简单构建块的系统组合来合成。由此产生的设备适应性强、重量轻、能效高，而且对人类交互来说本质上是安全的。它们将直接影响康复机器人、制造自动化、空间探索和外科手术等新兴领域。此外，该奖项将基于在自然和工程之间进行类比的总体主题，以增加未来工程师的创造性思维和增强解决问题的能力，同时强调扩大未被充分代表的群体在研究中的参与。为软机械系统制定通用设计框架的关键挑战涉及协商其结构组成部分之间的耦合非线性相互作用，即流体、可伸缩信封和增强纤维。该设计框架依赖于降阶模型来捕捉这些相互作用，并表征广义软机械构件的运动学和运动学-静力学行为。该模型可以推广到与封闭流体准静态相互作用下的任何结构或机制。使用这些模型，将开发一个设计框架来综合一个系统，其中几个具有不同属性的构建块基于从传统机器设计中改编的规则和指导原则，以串联或并行的结构组合在一起，例如约束匹配和几何精确运动学。设计框架还将纳入优化方法，以基于新的健壮性指标来优化系统。设计框架的成功实现将导致用于矫形支架的可重新配置的刚性系统和用于外科缝合和主动系绳应用的自打结活动绳。

This Faculty Early Career Development (CAREER) Program grant will pioneer a systematic synthesis, analysis and manufacturing framework to realize soft mechanical systems. Soft mechanical systems are static and dynamic structural embodiments that do not contain rigid components made of metals or plastics, conventional actuators such as motors, or interfaces such as joints and couplings. They are instead made up of stretchable skins, tissue-like appendages, fibers and fluids, and are inspired by around 90% of nature's animal species that lack a rigid backbone, such as an octopus arm. The unique feature of these systems is that they are flexible yet strong enough to bear large loads. Unfortunately, these systems have so far not been widely used, because a systematic design framework that can guide their physical realization does currently not exist. This award supports fundamental research that enables such a design framework, in which a soft mechanical system can be synthesized through a systematic combination of simple building blocks with pre-determined attributes. The resulting devices are adaptive, lightweight, energy-efficient and inherently safe for human interaction. They will directly impact the emerging fields of rehabilitation robotics, manufacturing automation, space exploration, and surgery. Furthermore, the award will build on the overarching theme of drawing analogies between nature and engineering to increase creative thinking and enhance problem solving abilities in future engineers, while emphasizing broadening participation of underrepresented groups in research.The key challenge in formulating a generalized design framework for soft mechanical systems involves negotiating the coupled nonlinear interactions among its structural constituents, namely, fluids, stretchable envelopes, and reinforced fibers. The design framework relies on reduced order models to capture these interactions and characterize the kinematic and kinemato-static behavior of a generalized soft mechanical building block. The models can be extended to any structure or mechanism under quasistatic interaction with enclosed fluids. Using these models, a design framework will be developed to synthesize a system, where several building blocks with varying attributes are combined in a series or parallel architecture based on rules and guidelines adapted from traditional machine design, such as constraint matching and geometrically exact kinematics. The design framework will also incorporate optimization methods to refine the system based on novel robustness metrics. Successful realization of the design framework will lead to a reconfigurable stiffness system for use in orthotic braces and a self-knotting active rope for use in surgical suturing and active tethering applications.