Mobility Analysis of the 3-UPU Parallel Mechanism Assembled for a Pure Translational Motion

Abstract

The occurrence of singular configurations in parallel mechanisms must be avoided during motion since the actuators cannot control motion even in the neighborhood of these configurations. As a consequence, the knowledge of the singular configurations of the mechanism is important for control purposes, for singularity-free path planning, and also represents basic information for the synthesis of a desired mechanism workspace free from singularities. In this paper the mobility analysis of the 3-UPU parallel mechanism assembled for obtaining a pure translation motion of the output platform is performed and both translation and rotation singularity loci are presented in analytic form and their geometric interpretation is given.

Parallel Manipulators with Lower Mobility

“…This singularity classification has been extended in (Zlatanov et al 1995) by taking into account the rates of the non-actuated joints. In the literature (Di Gregorio & Parenti-Castelli 2002;Di Gregorio 2001a, 2001b, 2004cZatlanov et al 2001Zatlanov et al , 2002, the possibility of changing the type of motion, the end effector performs, in correspondence of par-ticular type-(II) singularities, named constraint singularities, has been highlighted. Constraint singularities affect only LM-PMs where the limbs' connectivity is greater than the manipulator's dofs.…”

A Novel 4-DOF Parallel Manipulator H4

“…However, such a 3×3 Jacobian matrix cannot predict all possible singularities. Di Gregorio and Parenti-Castelli (Di Gregorio & Parenti-Castelli, 1999) analyzed the singularities of the 3-UPU translational platform. They derived the conditions for which the actuators cannot control the linear velocity of the moving platform, generally known as architecture singularities.…”

Some aspects of topology and kinematics of a 3DOF translational parallel mechanism

“…This mechanism and its generalizations were discussed with respect to kinematic properties especially focused on the possibility of generating pure translational motion in (e.g., Tsai, 1996;Di Gregorio and Parenti-Castelli, 1999;Kim and Chung, 2003;Bałchanowski, 2008;Walter and Husty, 2011;Chebii Ahmeg et al, 2013). The method of determination of mechanism configurations using contour vector notation was elaborated in the paper.…”