Clark Anthony J, Tan Xiaobo, McKinley Philip K
Department of Computer Science and Engineering, Michigan State University, East Lansing, MI, USA.
Bioinspir Biomim. 2015 Nov 25;10(6):065006. doi: 10.1088/1748-3190/10/6/065006.
Robotic fish accomplish swimming by deforming their bodies or other fin-like appendages. As an emerging class of embedded computing system, robotic fish are anticipated to play an important role in environmental monitoring, inspection of underwater structures, tracking of hazardous wastes and oil spills, and the study of live fish behaviors. While integration of flexible materials (into the fins and/or body) holds the promise of improved swimming performance (in terms of both speed and maneuverability) for these robots, such components also introduce significant design challenges due to the complex material mechanics and hydrodynamic interactions. The problem is further exacerbated by the need for the robots to meet multiple objectives (e.g., both speed and energy efficiency). In this paper, we propose an evolutionary multiobjective optimization approach to the design and control of a robotic fish with a flexible caudal fin. Specifically, we use the NSGA-II algorithm to investigate morphological and control parameter values that optimize swimming speed and power usage. Several evolved fin designs are validated experimentally with a small robotic fish, where fins of different stiffness values and sizes are printed with a multi-material 3D printer. Experimental results confirm the effectiveness of the proposed design approach in balancing the two competing objectives.
机器鱼通过使身体或其他鳍状附属物变形来实现游动。作为一类新兴的嵌入式计算系统，机器鱼有望在环境监测、水下结构检查、危险废物和石油泄漏追踪以及活鱼行为研究中发挥重要作用。虽然将柔性材料集成到鳍和/或身体中有望提高这些机器人的游动性能（在速度和机动性方面），但由于复杂的材料力学和流体动力学相互作用，这些部件也带来了重大的设计挑战。由于机器人需要满足多个目标（例如速度和能源效率），问题进一步加剧。在本文中，我们提出了一种进化多目标优化方法，用于设计和控制具有柔性尾鳍的机器鱼。具体而言，我们使用NSGA-II算法来研究优化游动速度和功率使用的形态和控制参数值。用一条小型机器鱼对几种进化后的鳍设计进行了实验验证，其中不同刚度值和尺寸的鳍是用多材料3D打印机打印的。实验结果证实了所提出的设计方法在平衡这两个相互竞争的目标方面的有效性。
