The 6-Dof 2-Delta parallel robot

Abstract

In this paper, we will present a new 6-DOF parallel robot using a set of two Delta structures. An effective method is proposed to establish explicit relationships between the end effector co-ordinates and the active and passive joint variables. A simulation of the 2-Delta robot on a C.A.D. Robotics system will also be presented. This simulation will allow us to validate the cohesion of our calculations, and to show the workspace depending on the mechanical limits on passive joints variables. Finally, an approach is proposed to study the influence of small clearances of the passive joint on the precision of the position and rotation of the effector. This approach is based on a concept similar to that of Yoshikawa's manipulability.

Dynamic modeling and control of the OMEGA-3 parallel manipulator

“…Although there have been inverse kinematic models expressed using passive joint angles [20,21], the kinematic analysis discussed here would only involve actuated joint angles, i . By leaving out the passive joint angles, a less complicated formulation of the inverse kinematics model can be developed with fewer unknowns to solve.…”

“…Equation (20) can be written in vector form, with the values for i as 1, 2, and 3, substituted to obtain the following expression, ,…”

Effects of constraint errors on parallel manipulators with decoupled motion

“…The set of 3 · 3 real skew-symmetric matrices, ŵ , forms the Lie algebra of SO(3), denoted by so (3). Note that a skew-symmetric matrix can be equivalently represented as a vector w 2 R 3Â1 for assigning the orientation of the end-effector in Section 4.4.…”

“…Hence, motion planning and control of the end-effector of PMs become very complicate. In order to cope with the motion coupling problem, researchers have studied some parallel manipulators with decoupled motion structures [1][2][3][4][5][6][7][8].…”

Kinematic design of a family of 6-DOF partially decoupled parallel manipulators

“…The displacement calculation, singularity analysis, workspace evaluation, statics analysis, motion planning and control are thus significantly simplified. Generally speaking, the 6-DOF DPMs have following advantages: 0094 In literature, Lallemand et al [6] introduced a 6-DOF 2-Delta DPM in which the external Delta robot is in charging for the translation of the end-effector, while the internal Delta robot is for controlling the orientation of the end-effector through one limb that allows free translation but no rotation. Shim et al [7] mentioned a decoupled 3-PRPS 6-DOF PM in which the two prismatic joints of each limb are actuators.…”