蛇怪蜥蜴踏水奔跑机理研究及仿生机构设计

Mechanism Study and Bionic Design of Water Running of Basilisk Lizard

  • 摘要: 蛇怪蜥蜴踏水奔跑过程中,脚掌会在气穴封闭前移出水面,并不断调整姿态适应变化的流场.为分析踏水机理,增加了对出水过程的研究,建立了脚掌进出水流体动力学模型,运用RNG(renormalization group)k-ε湍流方程,结合气穴扩张收缩变化,获得了最优上提时间.进一步针对脚掌姿态调整行为,解析了3维驱动力随入水角度的变化规律,推导了托举力与速度的数学函数,并通过实验初步验证了数值计算模型的正确性.以蛇怪蜥蜴为仿生对象,将脚掌往复踏水转变为叶片旋转击水,设计了水面矢量推进器,增加了驱动力输出维数,建立流体动力学模型,分析了叶片数量对力学性能的影响.进行推进器应用实验,实现了水面平台在10.6°仰角下的滑水航行.

     

    Abstract: When running on water surface, basilisk lizard will pull its foot upward before the air cavity closes and adjust position to adapt to the unsteady fluid field. To obtain the mechanism of water running, the hydrodynamic model of foot to enter water and come out of water is presented, in which the coming-out-of-water process is considered. Combined with RNG (renormalization group) k-ε turbulence equation, the optimal time of coming-out-of-water is obtained by analyzing expansion and contraction of air cavity. In view of adjustment of foot position, 3-dimensional driving forces changing with angle of entering water are analyzed, and the function between lift force and velocity is derived. By experiment, it is validated primarily that the numerical model is correct. For the bionic basilisk lizard, a water surface vector propeller is designed with transforming foot movement into impeller rotation, and the dimension of driving force is increased. The hydrodynamic model of the propeller is established to analyze the influence of impeller quantity on mechanical property. In the experiment of propeller application, the water surface device realizes hydroplaning navigation with pitch angle 10.6°.

     

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