TetraFLEX: Design and kinematic analysis of a novel self‐aligning family of 3T1R parallel manipulators

Abstract

A new family of 3T1R parallel manipulators (PMs) with self-aligning property, named TetraFLEX, is presented. 3T1R manipulators have many applications in different fields. Moreover, self-aligning property refers to the presence of passive joints in the PM limbs that are conceived to compensate for possible misalignments between the sliding directions of the actuated prismatic(P)-pairs. This property allows the fixation of the limbs in different frame geometries. Thus, this advantage broadens the PM applications to field robotics in several scenarios. Here, the position and singularity analyses of the new family of self-aligning PMs is addressed with a unified approach.The results are that both the direct and the inverse position analyses have simple closed-form solutions and that wide free-from-singularity regions of TetraFLEX PMs' workspace exist. The effectiveness of the technical proposal is also illustrated by discussing their design criteria and kinetostatics performances in a case study.

Instantaneous Kinematics and Free-from-Singularity Workspace of 3-XXRRU Parallel Manipulators

“…When the actuators are locked, all of the 3-XXRRU PMs, presented in [15], become 3-RRU structures (Figure 1). In the i-th RRU limb (Figure 1b), for i = 1, 2, 3, the axis, (A i , n i ) 6 , of the first R-pair is located through the coordinates of a point, A i , belonging to it, and a unit vector, n i , parallel to it.…”

Stiffness analysis and optimization of an asymmetric 3T1R parallel mechanism

“…11 The reference introduced a new series of SCARA PMs named TetraFLEX composed of a PRRR chain and three PRRS chains, this PM allowed the fixation of the limbs in different frame geometries that help to broaden the PM applications in more scenarios. 12 The development of these asymmetric PMs can provide more options for the industrial application to meet a variety of performance requirements.…”