A Hyper-redundant Elephant\u2019s Trunk Robot with an Open Structure: Design, Kinematics, Control and Prototype

Yongjie Zhao,Xinjian Lu,Xiaogang Song,Xingwei Zhang

doi:10.1186/s10033-020-00509-4

Abstract

As for the complex operational tasks in the unstructured environment with narrow workspace and numerous obstacles, the traditional robots cannot accomplish these mentioned complex operational tasks and meet the dexterity demands. The hyper-redundant bionic robots can complete complex tasks in the unstructured environments by simulating the motion characteristics of the elephant’s trunk and octopus tentacles. Compared with traditional robots, the hyper-redundant bionic robots can accomplish complex tasks because of their flexible structure. A hyper-redundant elephant’s trunk robot (HRETR) with an open structure is developed in this paper. The content includes mechanical structure design, kinematic analysis, virtual prototype simulation, control system design, and prototype building. This design is inspired by the flexible motion of an elephant’s trunk, which is expansible and is composed of six unit modules, namely, 3UPS-PS parallel in series. First, the mechanical design of the HRETR is completed according to the motion characteristics of an elephant’s trunk and based on the principle of mechanical bionic design. After that, the backbone mode method is used to establish the kinematic model of the robot. The simulation software SolidWorks and ADAMS are combined to analyze the kinematic characteristics when the trajectory of the end moving platform of the robot is assigned. With the help of ANSYS, the static stiffness of each component and the whole robot is analyzed. On this basis, the materials of the weak parts of the mechanical structure and the hardware are selected reasonably. Next, the extensible structures of software and hardware control system are constructed according to the modular and hierarchical design criteria. Finally, the prototype is built and its performance is tested. The proposed research provides a method for the design and development for the hyper-redundant bionic robot.

Highlights

With the introduction of the concept of Industry 4.0, robots have become more and more essential in intelligent manufacturing [1]
The motivation of the paper is to present the development of the hyper-redundant elephant’s trunk robot (HRETR) with an open structure including mechanical structure design, kinematic analysis, virtual prototype simulation, control system design, and prototype building
7 Conclusions In this paper, a prototype of a HRETR with expansibility is designed based on the principle of mechanical bionics while considering the special structure and movement mechanism of an elephant’s trunk muscle group

Summary

Introduction

With the introduction of the concept of Industry 4.0, robots have become more and more essential in intelligent manufacturing [1]. In order to improve the flexibility and adaptability of the robot in an unknown environment, Wang et al [22] proposed a cable-driven continuous robot They established its kinematic model and controlled it by a visual servo system. A HRETR with an open structure, which is composed of six 3UPS-PS parallel mechanism unit modules in series, is built based on the principle of mechanical bionics and based on the special structure characteristics and motion mechanism of an elephant’s trunk muscle group. 2.2 Integral Configuration Design of the HRETR The overall configuration of the HRETR comprises several 3UPS-PS parallel mechanism modules in series based on the research and analysis of the structural characteristics, motion mechanism of an elephant’s trunk, and the principle of miniaturization and lightweight.

Kinematic Analysis of the HRETR

Conclusions