斑马鱼C型机动运动数据重构与性能分析

The kinematics and performance of zebrafish C-shaped maneuvering

  • 摘要: 在鱼类机动性能研究中,获取高精度运动学和动力学实验数据至关重要。本文搭建基于机器视觉的高速摄影平台,获取了斑马鱼C型机动运动的顶视序列图像;使用数学形态学算法提取图像中的鱼体外轮廓和中线,建立了简化的三维鱼体模型;通过“鱼–水”系统的动量和动量矩守恒算法,获得鱼体的运动学数据,并分析了作用于鱼体的流体动力和机械能的变化规律。在鱼体模型建立过程中,对尾鳍进行面积的二阶矩等效处理,完成了尾鳍长度的合理修正。经一系列标准算例验证,采用数字图像处理技术重构的动力学数据与标准模型误差在3.1%以内。结果表明:鱼体C型机动运动中最大加速度与最大角加速度存在线性关系;C型起动中平动能占主导,C型转弯中转动能占主导。

     

    Abstract: It is difficult to obtain the complete kinematics and hydrodynamics from the experiments in the study of fish C-type fast-start, which can be divided into C-start and C-turn by the duration of maneuvers. Using high-speed photography, a series of top-view images of zebrafish's C-shaped maneuvering were obtained on the self-built platform based on machine vision. A simplified three-dimensional (3D) fish model was established according to the outline and midline of the fish body extracted from the images by using a mathematical morphology algorithm. Then, due to the conservation of the linear and angular momentum, the complete kinematic and hydrodynamic data during the whole maneuver motion can be obtained and the translational and rotational energy can be distinguished from the total kinetic energy of the zebrafish body. The modification of the caudal fin length is a highlight in 3D modeling, which is based on the equivalence of the area second-moment of a flapping 3D plate. Through the benchmark validation, the maximum geometric error of the digital image processing is less than 3.1%. The results show that the maximum acceleration in all the C-type fast-start is linearly related to the maximum angular acceleration, and the rotational energy of C-turn is dominant in the kinetic energy while the translational energy of C-start is dominant.

     

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