Multi-task oriented design of an asymmetric 3T1R type 4-DOF parallel mechanism

Abstract

In performing tasks requiring less than 6 degrees-of-freedom (DOF), lower mobility robots having a parallel structure are effective. This work investigates an asymmetric type 4 degrees-of-freedom parallel mechanism having Schö nflies motions. This mechanism would be useful for multi-purpose tasks because it incorporates a transmission linkage with appropriate output modules. The mobility analysis, kinematic modelling, and singularity analysis for the mechanism are performed. Optimal design parameters with respect to both the workspace size and kinematic isotropy are identified by employing composite global design index. In addition, to cope with the singularity problem, a new design involving redundant actuation is suggested. And dynamic simulations are conducted to reaffirm its high potential in real manufacturing applications.

Design of a new 6-DOF parallel mechanism with a suspended platform

“…Therefore, in the very initial design stage of parallel mechanisms, special care should be paid to the initial configuration of the mechanism in order to avoid the architecture singularity. Boney and Zlatanov [11], Kim et al [12,13] and Yi et al [14] partially analyzed architecture singlurality in the design of lower mobility mechanisms. Kim et al [15] developed a novel parallel mechanism having Schönflies motion and analyzed its singularity.…”

Design of a new gravity balanced parallel mechanism with Schönflies motion

“…15 Recently, an asymmetric 3T1R-PMs, which can provide multiple forms of output motion by attaching an additional transmission linkage, was developed by Yi et al. 16…”

“…Moreover, some other 3T1R-PMs were also developed, such as the fully isotropic Isoglide4, 12 partially decoupled Quadrupteron 13 and a novel 4 À PRP a R type parallel manipulator 14 in which the actuated joints are prismatic joints. Type synthesis of different topologies of fully parallel manipulator that can generate Scho¨nflies motion by using Theory of Group of Displacements was performed by Salgado et al 15 Recently, an asymmetric 3T1R-PMs, which can provide multiple forms of output motion by attaching an additional transmission linkage, was developed by Yi et al 16 Compared to the 3T1R-PMs with four limbs, some two-limbed 3T1R-PMs with simpler structure were also proposed, such as 2 À RRP a R type suggested by Kim et al 17 and 2 À RP a P a R type of McGill SMG 18 proposed by Angeles et al, which are actuated by the revolute joints. Here, R denotes a revolute joint and P a denotes a planar parallelogram.…”

A Synthesis Approach for Reconfigurable Redundant Parallel Kinematic Mechanisms

“…Urízar et al [14] studied the reconfiguration of a 3×SPS−S PKM into different assembly modes. Yi et al [15] presented a 4-dof multi-mode PKM. The challenge in synthesizing a RR-PKM is to incorporate the required redundancy to support the desired reconfiguration processes.…”