仿生水黾机器人水面行走动力学研究

The research on bionic water strider robot has long been viewed as a huge challenge in the field of micro-robotics for it is standing at the cutting edge of multi-interdisciplinary subject. Inspired by the movement mechanism of biological water strider, we propose to consider the particular impact stems from microstructures of material surface, especially when modeling the hydrodynamics of water-walking process. The wettability of the microstructure is simulated at the state of equilibrium, followed by static contact angle analysis through changing both the arrangement and constitution of molecules. Meanwhile, the dynamic contact angle equation is able to be obtained based on a nonequilibrium molecular dynamics approach, in which the critical factor of wettability level is mainly determined by the hydrophobicity of microstructure and sliding speed. Then static and dynamic contact angles will contribute directly to establish the relationship among microstructure, hydrophobicity and hydrodynamics of actuation leg. According to the rule of contact angle when sliding on the water, the arrangement of microstructures could be optimized, this will provide a theoretical model for the fabrication of novel hydrophobic material. Combined with computational fluidic mechanics approach, a dynamic model of the actuation leg could be realized which serves as the theoretical basis of improving both the mobility and the stability of biomimetic motion.

仿生水黾机器人的研究被誉为"对微型机器人研究的极限挑战"，是多学科交叉前沿课题。借鉴生物水黾的运动机理，本项目提出在机器人行走水动力学建模中考虑材料表面微观结构的影响：采用平衡状态模拟分析材料微观浸润性，改变材料微观的分子组成与排列方式，分析其对静态接触角影响规律；采用非平衡状态分子动力学模拟方法，通过模拟材料微观浸润过程，分析仿生水黾机器人划水运动时疏水性材料微观结构、划水速度对材料浸润状态的影响规律，建立材料动态接触角函数表达；以静态接触角、动态接触角建立材料微观结构影响与材料疏水性、驱动腿水动力学分析之间的联系，分析水黾疏水性及划水运动时动态接触角变化规律，以此为优化标准，研究材料微观组成与排列的优化方法，为疏水性材料的仿生制备提供理论基础；结合计算流体力学数值模拟方法分析驱动腿受力变化，建立动力学模型，为提高机器人水面滑行时机动性、稳定性，实现仿生运动提供必要的理论研究基础。

仿生水黾机器人的研究被誉为“对微型机器人研究的极限挑战”，为借鉴生物水黾的运动机理，提高机器人的运动性能，本项目研究了疏水性材料表面微观结构对机器人行走水动力学建模中的影响。（1）基于分子动力学模拟方法研究了材料微观结构对疏水性能的影响，获得了平衡条件与非平衡条件下材料浸润状态、微观作用力等的变化规律。（2）基于界面自由能理论以及Young-Laplace方程实现了涵盖材料微观结构影响的支撑腿、驱动腿水动力学建模，为提高机器人水面机动性、稳定性，提供必要的理论研究基础。（3）基于以上研究理论，设计并制作了第一台能够实现机器人类物水黾驱动腿椭圆形划水轨迹的表面张力驱动微型仿水黾机器人，第一台能够在水面连续跳跃的仿水黾水面跳跃机器人，并通过实验与仿真分析了机器人的水面运动性能、抗干扰能力，对前期理论研究进行了验证。