Soft slender robots have attracted more and more research attentions in these years due to their continuity and compliance natures. However, mechanics modeling for soft robots interacting with environment is still an academic challenge because of the nonlinearity of deformation and the nonsmooth property of the contacts. In this work, starting from a piece-wise local strain field assumption, we propose a nonlinear dynamic model for soft robot via Cosserat rod theory using Newtonian mechanics, which handles the frictional contact with environment and transfer them into the nonlinear complementary constraint (NCP) formulation. Moreover, we smooth both the contact and friction constraints in order to convert the inequality equations of NCP to the smooth equality equations. The proposed model allows us to compute the dynamic deformation and frictional contact force under common optimization framework in real time when the soft slender robot interacts with other rigid or soft bodies. In the end, the corresponding experiments are carried out which valid our proposed dynamic model.

中文翻译：

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基于 Cosserat 杆的软细长机器人与环境交互的动态建模

软细长机器人由于其连续性和柔顺性，近年来引起了越来越多的研究关注。然而，由于变形的非线性和接触的非光滑特性，软机器人与环境相互作用的力学建模仍然是一个学术挑战。在这项工作中，从分段局部应变场假设出发，我们利用牛顿力学通过 Cosserat 杆理论提出了软体机器人的非线性动力学模型，该模型处理与环境的摩擦接触并将其转移到非线性互补约束（NCP）中公式。此外，我们对接触和摩擦约束进行了平滑处理，以便将 NCP 的不等式方程转换为平滑的等式方程。所提出的模型使我们能够在通用优化框架下实时计算软细长机器人与其他刚性或软体交互时的动态变形和摩擦接触力。最后，进行了相应的实验，验证了我们提出的动力学模型。