This work is motivated by the development of cooperative teams of small, soft underwater robots designed to accomplish complex tasks through collective behavior. These robots take inspiration from biology: salps are gelatinous, jellyfish-like marine animals that utilize jet propulsion for maneuvering and can physically connect to form dynamic chains of arbitrary shape and size. The primary contributions of this research are twofold: first, we adapt a planar nonlinear multi-link snake robot model to model a planar multi-link salp-inspired system by removing joint actuators, introducing link thrusters, and allowing for non-uniform link lengths, masses, and moments of inertia. Second, we conduct a nonlinear observability analysis of the multi-link system with link thrusters, showing that the link angles, angular velocities, masses, and moments of inertia are locally observable when equipped with inertial measurement units and operating under specific thruster conditions. This research provides a theoretical foundation for modeling and estimating both the state and intrinsic parameters of a multi-link system with link thrusters, which are essential for effective controller design and performance.

翻译：本研究受小型柔性水下机器人协同团队发展的启发，该团队旨在通过集体行为完成复杂任务。这些机器人从生物学中获得灵感：樽海鞘是一种胶质、类似水母的海洋动物，利用喷水推进进行机动，并能物理连接形成任意形状和大小的动态链。本研究的主要贡献有两个方面：首先，我们通过移除关节执行器、引入连杆推进器并允许非均匀的连杆长度、质量和转动惯量，将平面非线性多连杆蛇形机器人模型适配为平面多连杆樽海鞘仿生系统的建模。其次，我们对带连杆推进器的多连杆系统进行了非线性可观测性分析，结果表明当配备惯性测量单元并在特定推进器条件下运行时，连杆角度、角速度、质量及转动惯量是局部可观测的。本研究为带连杆推进器的多连杆系统的状态及固有参数建模与估计提供了理论基础，这对于有效的控制器设计与性能至关重要。