Type Synthesis of 5-DoF Parallel Mechanisms with Different Submechanisms

Yi Lu,Nijia Ye,Yang Lu,Bo Hu,Lijie Zhang,Yang Liu

doi:10.1155/2018/6021702

Abstract

The type synthesis of the 5-DoF (degree of freedom) parallel mechanisms with different submechanisms is studied by utilizing digital topology graphs (DTGs). The conditions for synthesizing the 5-DoF parallel mechanisms with different submechanisms using DTGs are determined. Many valid DTGs are derived from 17 different 5-DoF associated linkages, and the valid DTGs are transformed into revised DTGs. The subplanar and/or spatial parallel mechanisms in the 5-DoF parallel mechanisms are transformed into some simple equivalent limbs, and their equivalent relations and merits are analyzed. Using the derived valid DTGs and revised DTGs, many 5-DoF parallel mechanisms with different subserial or parallel mechanisms are synthesized, and they are simplified by replacing the complicated subparallel mechanisms with their simple equivalent limbs. Finally, their DoFs are calculated to verify the correctness and effectiveness of the proposed approach.

Highlights

Type synthesis of mechanisms is a well-known technology for creating and designing novel mechanisms [1,2,3,4,5]
This paper focuses on the type synthesis of the 5-DoF parallel mechanisms (PMs) with subserial mechanisms, subplanar mechanisms, and subPMs or their combinations by utilizing valid digital topology graphs (DTGs)
In this DTG, 1q is represented by 1 vertex which are connected by 4 edges ej (j = 1, 2, 4, 5) marked by digits (4, 4, 4, 5), respectively. 2t are represented by 2 vertices which are connected by 5 edges ej (j = 1, . . . , 5) marked by digits (4, 4, 1, 4, 5), respectively

Summary

Introduction

Type synthesis of mechanisms is a well-known technology for creating and designing novel mechanisms [1,2,3,4,5]. A contracted graph (CG) without any binary link is applied for deriving TG In this aspect, Vucina and Freudenstein [9] and Tsai and Norton [10] proposed TG and CG and used them to synthesize mechanisms. Let “R, P, C, U, and S” represent “revolute, prismatic, cylinder, universal, and spherical” pairs, respectively In this aspect, Gao et al developed a 5-DoF parallel machine tool with 4 PSS limbs and a composite 3UU limb [18]. It is a significant and challenging issue to synthesize novel 5-DoF PMs with special functions and/or better characteristics (large position and orientation workspace, large capability of load bearing, high stiffness, simple structure, and easy control) For this reason, this paper focuses on the type synthesis of the 5-DoF PMs with subserial mechanisms, subplanar mechanisms, and subPMs or their combinations by utilizing valid DTGs (digital topology graph). The following problems are solved: (1) constructing various DTGs of 5-DoF PMs by utilizing 17 ALs; (2) determining the relationship between the valid DTGs and the equivalent limbs of the subplanar mechanisms and subPMs; (3) synthesizing the 5-DoF PMs with the subplanar or sub-PMs by utilizing valid DTGs

Concepts and Conditions

Valid DTGs and Revised DTGs

Submechanisms and Their Equivalent Limbs

Conclusions

B: Fixed base