Purpose

The purpose of this paper is to introduce a tetrahedral mobile robot with only revolute joints (TMRR). By using rotation actuators, the mechanism of the robot gains favorable working space and eliminates the engineering difficulties caused by the multilevel extension compared with liner actuators. Furthermore, the rolling locomotion is improved to reduce displacement error based on dynamics analysis.

Design/methodology/approach

The main body of deforming mechanism with a tetrahedral exterior shape is composed of four vertexes and six RRR chains. The mobile robot can achieve the rolling locomotion and reach any position on the ground by orderly driving the rotation actuators. The global kinematics of the mobile modes are analyzed. Dynamics analysis of the robot falling process is carried out during the rolling locomotion, and the rolling locomotion is improved by reducing the collision impulse along with the moving direction.

Findings

Based on global kinematics analysis of TMRR, the robot can realize the continuous mobility based on rolling gait planning. The main cause of robot displacement error and the corresponding improvement locomotion are gained through dynamic analysis. The results of the theoretical analysis are verified by experiments on a physical prototype.

Originality/value

The work introduced in this paper is a novel exploration of applying the mechanism with only revolute joints to the field of tetrahedral rolling robots. It is also an attempt to use the improved rolling locomotion making this kind of mobile robot more practical. Meanwhile, the reasonable engineering structure of the robot provides feasibility for load carrying.

中文翻译：

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仅带旋转关节（TMRR）的四面体移动机器人的设计与运动分析

目的

本文的目的是介绍一种只有旋转关节 (TMRR) 的四面体移动机器人。通过使用旋转执行器，机器人的机构获得了有利的工作空间，与直线执行器相比，消除了多级扩展带来的工程困难。此外，在动力学分析的基础上，改进了滚动运动以减少位移误差。

设计/方法/方法

具有四面体外形的变形机构主体由四个顶点和六个 RRR 链组成。移动机器人通过依次驱动旋转执行器，实现滚动运动，到达地面任意位置。分析了移动模式的全局运动学。在滚动运动过程中对机器人下落过程进行动力学分析，通过减小沿运动方向的碰撞冲量来改善滚动运动。

发现

基于TMRR的全局运动学分析，机器人可以实现基于滚动步态规划的连续运动。通过动力学分析得出机器人位移误差的主要原因及相应的改进运动。理论分析的结果通过在物理原型上的实验得到验证。

原创性/价值

本文介绍的工作是将只有旋转关节的机构应用于四面体滚动机器人领域的新探索。也是尝试使用改进的滚动运动使这种移动机器人更加实用。同时，机器人合理的工程结构为承载提供了可行性。