Structural Synthesis of Parallel Mechanisms with High Rotational Capability

Abstract

Most parallel mechanisms (PMs) encountered today have a common disadvantage, i.e., their low rotational capability. In order to develop PMs with high rotational capability, a family of novel manipulators with one or two dimensional rotations is proposed. The planar one-rotational one-translational (1R1T) and one-rotational two-translational (1R2T) PMs evolved from the crank-and-rocker mechanism (CRM) are presented by means of Lie group theory. A spatial 2R1T PM and a 2R parallel moving platform with bifurcated large-angle rotations are proposed by orthogonal combination of the RRRR limbs. According to the product principle of the displacement group theory, a hybrid 2R3T mechanism in possession of bifurcated motion is obtained by connecting the 2R parallel moving platform with a parallel part, which is constructed by four 3T1R kinematic chains. The presented manipulators possess high rotational capability. The proposed research enriches the family of spatial mechanisms and the construction method provides an instruction to design more complex mechanisms. which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made.

Type synthesis and performance analysis of manipulators with shape adaptability

“…At present, the research of manipulator is mainly focuses on synthesis of configuration, kinematic and dynamics analysis, and design of control system. [12][13][14][15][16][17][18][19][20][21][22][23] Therefore, in view of the actual situation in the field of machining and manufacturing, this paper takes parallel mechanism as the research object, and proposes a control mechanism based on variable platform, 4-RRS& planar four-bar mechanism, in order to solve the problems existing in the current industrial parts processing line. The specific research contents are as follows (as shown in Figure 1): In Section ''Type synthesis,'' the topological structure design is carried out based on the finite screw theory, and the structural characteristics of 4-RRS& planar four-bar mechanism are described.…”

A synthesis method for planetary gear trains based on new topological model and similarity

“…Then, as the core of structural synthesis, isomorphism identification aims to exclude repeated structure types. Many scholars have proposed various isomorphism identification methods for PGTs, such as loop algebra theory [13,22], displacement group theory [23], multi-order adjacent vertex assignment sequence [24], equivalent resistance matrix [25], and vertex correlation polynomial and vertex distance [26][27], topological index [28], and modified eigenvalue eigenvector [29].…”