Maneuvering Bioinspired Soft Microrobots in Anisotropic Complex Fluids

微型机器人有可能接触到深层器官来输送药物或进行微创手术。但要实现这一愿景，需要解决几个科学和技术挑战，其中关键是为在生物液体中高效游泳和机动而量身定做的机器人系统的设计。这些流体具有独特的物理和流变性，可以促进或阻碍细胞运动。受精子细胞游动运动的启发，该项目旨在开发、控制和分析磁性驱动的、类似精子的软微型机器人在纳米纤维液体悬浮液中的运动，其特性类似于宫颈粘液。这个由NSF资助的项目的研究重点将与全面的教育和推广活动紧密结合在一起，旨在教育和培训来自不同背景的未来科学家和工程师，从事动力学与控制、机器人学、生物材料和流体力学交叉学科的研究。研究活动将结合实验和计算努力：(A)研究人造宫颈粘液(ACM)中磁弹性波动微型机器人的流体-结构相互作用；(B)寻找最佳游泳步态和最小反馈控制器；(C)利用依赖方向的游泳行为来检测流体特性，并将微型机器人引导到特定位置。高分辨率3D打印将被用来制造比刚性微机器人具有更多自由度的软微机器人，从而在凝胶状ACM中穿越障碍时获得更大的运动性。远程磁控将驱动复杂的鞭毛跳动模式，以产生直线和转弯运动。在相应的计算机模拟中，浸没边界方法将被用来解决ACM中单个和多个微型机器人的流固相互作用，并揭示它们与方位相关的游泳机制。然后，这些数据将与最先进的多目标优化工具一起使用，以构建最小无模型控制策略。成功完成这些研究任务将带来微型机器人设计、分析、优化和评估的新范例。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

Microrobots have the potential to reach deep organs to deliver drugs or perform minimally invasive surgeries. But to realize such a vision, several scientific and technological challenges need to be resolved, key among them is the design of robotic systems tailored for efficient swimming and maneuvering in biological fluids. These fluids have unique physical and rheological properties that can facilitate or hinder cell movement. Inspired by the swimming motions of sperm cells, this project aims to develop, control, and analyze the motion of magnetically driven, sperm-like soft microrobots in nanofiber fluid suspensions with properties analogous to cervical mucus. Research thrusts of this NSF funded project will be tightly coupled with comprehensive educational and outreach activities, and are designed to educate and train future scientists and engineers from diverse backgrounds in interdisciplinary research at the intersection of dynamics and control, robotics, biomaterials, and fluid mechanics.The research activities will combine experimental and computational efforts to: (a) study fluid-structure interactions of magnetoelastic undulatory microrobots in artificial cervical mucus (ACM); (b) seek optimal swimming gaits and minimal feedback controllers; (c) exploit orientation-dependent swimming behavior to detect fluid properties and steer to the microrobot to specific sites. High-resolution 3D printing will be used to fabricate soft microrobots with larger number of degrees of freedom than their rigid counterparts, leading to greater motility as they negotiate obstacles in gel-like ACMs. Remote magnetic control will drive complex flagellum beating patterns to generate straight and turning motions. In accompanying computer simulations, Immersed Boundary methods will be used to resolve fluid-structure interactions of single and multiple microrobots in ACMs, and uncover their orientation-dependent swimming mechanisms. The data will then be used with state-of-the-art multi-objective optimization tools, to construct a minimal model-free control strategy. Successful completion of these research tasks will result in a new paradigm for microrobot design, analysis, optimization, and evaluation.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.