Kinematic Analysis of RS type Parallel Robotic Mechanisms A Performance Index Based Approach

Abstract

Parallel Robotic Mechanisms (PRMs) have been the subject of study about robotic research during the past three decades. A parallel robotic mechanism typically consists of a moving platform that is connected to a fixed base by minimum of two kinematic chains in parallel. The beneficial features about Parallel Robotic Mechanisms over their serial counterpart in terms of stiffness, accuracy, and low inertia, are better. So these good features made to enable them to become viable alternatives for wide applications instead of serial one. But Parallel mechanisms also have some non-beneficial features, such as complex forward kinematics, singularity problem, Compact workspace, complicated structures and a high cost. These parallel mechanisms which are used in many precise task applications such as material handling, flight simulation, optical fibre alignment, Automobile simulation etc. newlineIn this Thesis, the Kinematic performance analysis of 3 legged, novel Revolute-Spherical (RS) type family of PRMs were investigated based on a performance index approach. The RS type family of parallel mechanisms compromises of eight 6 DoF and four 3 DoF based configurations. This family comprises of eight variants of mechanisms and each having six degrees of freedom (DoF), consists of (RRRS) Revolute-Revolute-Revolute-Spherical, (RPRS)Revolute-Prismatic-Revolute-Spherical, (PRRS)Prismatic-Revolute-Revolute-Spherical, (PPRS)Prismatic-Prismatic-Revolute-Spherical) configurations and (RRS) Revolute-Revolute-Spherical (RRxS) Revolute-Revolute(x-axisof rotation)-Spherical (PRS) Prismatic-Revolute-Spherical (PRxS) Prismatic-Revolute(x-axisof rotation)-Spherical for 3 DoF mechanisms. Among the eight 6 DoF parallel mechanisms, the first four parallel mechanisms were proposed with the combination of Straight and Arc type linkage and the remaining four 6 DoF PRMs were using straight linkage configurations. newline