Recent research on mobile robots has focused on increasing their adaptability to unpredictable and unstructured environments using soft materials and structures. However, the determination of key design parameters and control over these compliant robots are predominantly iterated through experiments, lacking a solid theoretical foundation. To improve their efficiency, this paper aims to provide mathematics modeling over two locomotion, crawling and swimming. Specifically, a dynamic model is first devised to reveal the influence of the contact surfaces' frictional coefficients on displacements in different motion phases. Besides, a swimming kinematics model is provided using coordinate transformation, based on which, we further develop an algorithm that systematically plans human-like swimming gaits, with maximum thrust obtained. The proposed algorithm is highly generalizable and has the potential to be applied in other soft robots with multiple joints. Simulation experiments have been conducted to illustrate the effectiveness of the proposed modeling.

翻译：近年来，移动机器人的研究重点在于利用软性材料和结构提升其对不可预测和非结构化环境的适应性。然而，这类柔顺机器人的关键设计参数确定与控制主要依赖实验迭代，缺乏坚实的理论基础。为提高其效率，本文针对爬行与游泳两种运动方式建立数学模型。具体而言，首先构建动力学模型以揭示接触面摩擦系数对不同运动阶段位移的影响。此外，通过坐标变换建立游泳运动学模型，并基于该模型进一步开发了一种算法，可系统性地规划类人游泳步态，同时获得最大推力。该算法具有高度泛化能力，有望应用于其他多关节软体机器人。通过仿真实验验证了所提模型的有效性。