Microspine Design for Additive Manufacturing

Microspine grippers allow robots to ascend steep rocky slopes and cliff faces, enabling scientific exploration of exposed strata on Earth and other solar system bodies. Historically, the Shape Deposition Manufacturing (SDM) process has been used to fabricate multi-material suspensions for load-sharing among multiple microspines. We instead apply the Hybrid Deposition Manufacturing (HDM) process to microspine fabrication, and we further propose a novel 3D-printed microspine suspension design that can be manufactured via Fused Deposition Manufacturing (FDM) alone, using a single flexible material with an embedded fishhook. We use a model of microspine stiffness that allows designers to compensate for order-of-magnitude changes in material tensile modulus by adjusting geometric parameters of the design. The stiffness model and the FDM microspine design are validated through tensile testing, and mechanical properties of the HDM and FDM designs are compared against a standard SDM microspine design. We demonstrate that the FDM process can produce microspines with equivalent normal and axial stiffness and superior maximum load and fatigue response to SDM microspines, and discuss additional advantages of the FDM process for rapid prototyping and broader accessibility.

微棘抓具可使机器人攀爬陡峭的岩石斜坡与崖壁，为地球及太阳系其他天体上裸露地层的科学探索提供可能。历史上，形状沉积制造（Shape Deposition Manufacturing，SDM）工艺被用于制备多材料悬架，以实现多个微棘之间的载荷分担。我们转而将混合沉积制造（Hybrid Deposition Manufacturing，HDM）工艺应用于微棘制备，并进一步提出一种新型3D打印微棘悬架设计——该设计仅需通过熔融沉积制造（Fused Deposition Manufacturing，FDM）工艺即可完成，使用单一柔性材料并嵌入鱼钩。我们采用微棘刚度模型，该模型可让设计者通过调整设计的几何参数，补偿材料拉伸模量的数量级变化。我们通过拉伸试验验证了该刚度模型与FDM微棘设计，并将HDM与FDM设计的力学性能与标准SDM微棘设计进行对比。结果表明，FDM工艺制备的微棘具有与SDM微棘相当的法向及轴向刚度，且在最大载荷与疲劳响应方面更优；此外，我们还探讨了FDM工艺在快速原型制作与更广泛可及性方面的额外优势。