Indian Journal of Science and Technology

Abstract

This contribution addresses forward kinematic solution of modular hybrid manipulator which includes two same Stewart mechanism in serial form known as 2-(6UPS) manipulator. First, using geometrical and vectorial analysis, mathematical model of kinematic analysis for 2-(6UPS) is extracted. Mapping the length of pods to location (orientation and position) of moving mid and upper platforms (forward kinematic) in this specific mechanism is difficult to solve, as it is related to complicated configuration of 2-(6UPS) and highly nonlinear characteristic of extracted mathematical model. Therefore, we propose artificial neural network (ANN) based wavelet analysis to resolve forward kinematics of 2-(6UPS). Also, we used wavelet neural network (WNN) to approximate specific trajectory in smooth circle and semi-cardioid paths for mid and upper platforms movement respectively. Comparison between the results of proposed network and closed form solution (CFS) of kinematics for 2-(6UPS) shows proper performance of proposed network in less than 1% error.

Keywords: 2-(6UPS) Manipulators, Forward Kinematics Analysis, Nonlinear Multivariable System, Stewart Mechanism, WNN