State Key Laboratory for Turbulence and Complex Systems, College of Engineering, Peking University, Beijing 100871, People's Republic of China. Author to whom correspondence may be addressed.
Bioinspir Biomim. 2019 May 2;14(4):046001. doi: 10.1088/1748-3190/ab1052.
Moving in groups is an amazing spectacle of collective behaviour in fish and has attracted considerable interest from many fields, including biology, physics and engineering. Although robotic fish have been well studied, including algorithms to simulate group swimming, experiments that demonstrate multiple robotic fish as a stable group are yet to be achieved. One of the challenges is the lack of a robust bottom-level motion control system for robotic fish platforms. Here we seek to overcome this challenge by focusing on the design and implementation of a motion controller for robotic fish that allows multiple individuals to swim in groups. As direction control is essential in motion control, we first propose a high-accuracy controller which can control a sub-carangiform robotic fish from one arbitrary position/pose (position and direction) to another. We then develop a hydrodynamic-model-based simulation platform to expedite the process of the parameter tuning of the controller. The accuracy of the simulation platform was assessed by comparing the results from experiments on a robotic fish using speeding and turning tests. Subsequently, extensive simulations and experiments with robotic fish were used to verify the accuracy and robustness of the bottom-level motion control. Finally, we demonstrate the efficacy of our controller by implementing group swimming using three robotic fish swimming freely in prescribed trajectories. Although the fluid environment can be complex during group swimming, our bottom-level motion control remained nominally accurate and robust. This motion control strategy lays a solid foundation for further studies of group swimming with multiple robotic fish.
群体运动是鱼类集体行为的一种惊人现象，引起了包括生物学、物理学和工程学在内的许多领域的极大兴趣。尽管机器鱼已经得到了很好的研究，包括模拟群体游泳的算法，但还没有实现多个机器鱼作为一个稳定群体的实验。其中一个挑战是缺乏用于机器鱼平台的稳健底层运动控制系统。在这里，我们专注于设计和实现一种用于机器鱼的运动控制器，以允许多个个体进行群体游泳。由于方向控制在运动控制中至关重要，我们首先提出了一种高精度控制器，可以将一条亚鲱形机器鱼从任意位置/姿态（位置和方向）控制到另一个位置/姿态。然后，我们开发了一个基于水动力模型的仿真平台，以加快控制器参数调整的过程。通过对机器鱼进行加速和转弯测试来比较实验结果，评估了仿真平台的准确性。随后，使用机器鱼进行了广泛的仿真和实验，以验证底层运动控制的准确性和鲁棒性。最后，我们通过使用三艘机器鱼在预定轨迹上自由游动来展示我们的控制器的有效性。尽管在群体游泳时流体环境可能很复杂，但我们的底层运动控制仍然保持名义上的准确性和鲁棒性。这种运动控制策略为进一步研究多机器鱼的群体游泳奠定了坚实的基础。
