Abstract In this paper, a novel deployable tetrahedron-based mobile robot constructed by Sarrus linkages with eight degrees of freedom (DOFs) is proposed. The robot is composed of a core tetrahedron and four branch tetrahedrons with a total of eight nodes and 18 planar RRR chains (R denotes revolute joint), and each node and any two branch chains connected to it is a Sarrus linkage. Referring to the kinematics of the general-type Sarrus linkage, the kinematics of the robot is analyzed in detail. Based on it, two non-impact rolling gaits of rolling in Direction I/II and rolling in Direction III are discussed, then the continuous non-impact rolling locomotion is elaborated. Besides, two folding modes of folding as an umbrella shape and deploying in radially reciprocating motion are developed. Finally, a prototype is manufactured, the rolling experiments indicate that the robot can roll in any direction for arbitrary distance with the trajectory of a series of triangles, and the two additional folding modes increase the convenience of storage and transportation of the robot.

中文翻译：

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Sarrus连杆构造的可展开四面体移动机器人的设计与分析

摘要 在本文中，提出了一种由具有八自由度（DOF）的 Sarrus 连杆构造的新型可展开四面体移动机器人。该机器人由一个核心四面体和四个分支四面体组成，共有8个节点和18条平面RRR链（R表示旋转关节），每个节点和与其相连的任意两条支链都是一个Sarrus连杆。参考通用型Sarrus连杆机构的运动学，对机器人的运动学进行了详细分析。在此基础上，讨论了I/II方向滚动和III方向滚动两种无冲击滚动步态，阐述了连续无冲击滚动运动。此外，还开发了折叠成伞状和径向往复展开两种折叠方式。最后，制造了一个原型，