Huang, XiaonanPatterson, Zach J.Sabelhaus, Andrew P.Huang, WeichengChin, KiynRen, ZhijianJawed, Mohammad KhalidMajidi, Carmel2025-05-022025-05-022022-10X. Huang, Z.J. Patterson, A.P. Sabelhaus, W. Huang, K. Chin, Z. Ren, M.K. Jawed, C. Majidi. 2022. "Design and Closed‐Loop Motion Planning of an Untethered Swimming Soft Robot Using 2D Discrete Elastic Rods Simulations" Advanced Intelligent Systems, Volume 4, Issue 10. https://doi.org/10.1002/aisy.2022001632640-4567https://hdl.handle.net/2144/50319Despite tremendous progress in the development of untethered soft robots in recent years, existing systems lack the mobility, model‐based control, and motion planning capabilities of their piecewise rigid counterparts. As in conventional robotic systems, the development of versatile locomotion of soft robots is aided by the integration of hardware design and control with modeling tools that account for their unique mechanics and environmental interactions. Here, a framework for physics‐based modeling, motion planning, and control of a fully untethered swimming soft robot is introduced. This framework enables offline co‐design in the simulation of robot parameters and gaits to produce effective open‐loop behaviors and enables closed‐loop planning over motion primitives for feedback control of a frog‐inspired soft robot testbed. This pipeline uses a discrete elastic rods (DERs) physics engine that discretizes the soft robot as many stretchable and bendable rods. On hardware, an untethered aquatic soft robot that performs frog‐like rowing behaviors is engineered. Hardware validation verifies that the simulation has sufficient accuracy to find the best candidates for sets of parameters offline. The simulator is then used to generate a trajectory library of the robot's motion in simulation that is used in real‐time closed‐loop path following experiments on hardware.en© 2022 The Authors. Advanced Intelligent Systems published by Wiley-VCH GmbH. This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.https://creativecommons.org/licenses/by/4.0/Model-based controlMotion planningSimulationSoft roboticsControl engineering, mechatronics and roboticsArtificial intelligenceArticle10.1002/aisy.2022001630000-0003-4371-7442 (Patterson, Zach J)0000-0001-5019-2846 (Sabelhaus, Andrew P)0000-0002-6469-9645 (Majidi, Carmel)766515