Kinematics of swimming of the manta ray: three-dimensional analysis of open-water maneuverability
Kinematics of swimming of the manta ray: three-dimensional analysis of open-water maneuverability
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DOI：
10.1242/jeb.166041
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发表时间：
2018-03-01
影响因子：
2.8
通讯作者：
Bart-Smith, Hilary
中科院分区：
文献类型：
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作者：
Fish, Frank E.;Kolpas, Allison;Bart-Smith, Hilary
对于水生动物来说，转弯动作代表一种可能不局限于单个坐标平面的运动活动，这使得分析变得困难，特别是在野外。为了测量大型开放水域游泳者蝠鲼 (Mobula birostris) 在三维空间中的转弯性能，收集了按比例缩放的立体视频记录。追踪头叶、眼睛和尾根的运动以获得三维坐标。对坐标数据进行数学分析，通过数值估计蝠鲼轨迹在三维空间中的导数来计算作为时间函数的转弯速率和曲率（1/转弯半径）。主成分分析用于将三维轨迹投影到二维转弯上。对这些转弯应用了平滑样条。这些是灵活的模型，可以通过控制数据保真度和导数规律性之间平衡的参数来最小化成本函数。执行缓慢、稳定转弯的 30 个射线序列的数据显示，转弯速率的最高 20% 值和转弯半径的最小 20% 分别为 42.65 +/- 16.66 deg s(-1) 和 2.05 +/- 1.26 m。这种转身动作属于具有刚体的游泳者所表现出的性能范围。
For aquatic animals, turning maneuvers represent a locomotor activity that may not be confined to a single coordinate plane, making analysis difficult, particularly in the field. To measure turning performance in a three-dimensional space for the manta ray (Mobula birostris), a large open-water swimmer, scaled stereo video recordings were collected. Movements of the cephalic lobes, eye and tail base were tracked to obtain three-dimensional coordinates. A mathematical analysis was performed on the coordinate data to calculate the turning rate and curvature (1/turning radius) as a function of time by numerically estimating the derivative of manta trajectories through three-dimensional space. Principal component analysis was used to project the three-dimensional trajectory onto the two-dimensional turn. Smoothing splines were applied to these turns. These are flexible models that minimize a cost function with a parameter controlling the balance between data fidelity and regularity of the derivative. Data for 30 sequences of rays performing slow, steady turns showed the highest 20% of values for the turning rate and smallest 20% of turn radii were 42.65 +/- 16.66 deg s(-1) and 2.05 +/- 1.26 m, respectively. Such turning maneuvers fall within the range of performance exhibited by swimmers with rigid bodies.