Kinematic and Stiffness Analysis of 3-PRS Parallel Kinematic Mechanism

Abstract

Parallel kinematic manipulators have a well advantage over the serial manipulators due to their higher stiffness and large load carrying capacity. These advantages have increased the uses of parallel mechanisms in many applications. This thesis mainly addresses the issues regarding stiffness estimation of prismatic revolute spherical (3PRS) parallel mechanism. A simple and comprehensive approach is presented to estimate the stiffness of 3PRS mechanism. As the name, the 3PRS manipulator has three identical limbs with each limb have prismatic revolute and spherical joint. In order to get the desired goal of this research, the kinematic with forward and inverse analysis, jacobian, and singularity analysis is performed and discussed as the root. Autodesk inventor professional software is used to design the CAD model of the proposed 3PRS mechanism. Starting with the inverse kinematics an analytical model is derived. As well as the forward kinematic both analytical and numerical analysis is performed to ensure the efficiency of the presented methodology; the results are compared with the presented CAD model. Singularity analysis is done and three common types of singularities are discussed in this thesis. The results of the inverse and forward kinematics are obtained by writing a program in MATLAB® . The results are compared with the prototype CAD model and they are closely related. The stiffness model results obtained by numerical calculations are compared with the FEA of the CAD model. These results are closely matched with a percentage error of 0.1 %.