Experimental investigation on position analysis of 3-DOF parallel manipulators

Parallel manipulators (PMs) have been the subject of study, of much robotic research during the past three decades. A parallel manipulator (PM) is a closed loop kinematic chain mechanism, that is connected to the base via multiple independent chains. The scope of this research work is to perform the position analyses of the three degrees of freedom PMs (TRIPOD and TRI-GLIDE). The present work has been planned to model the parallel manipulators using the screw joints for very accurate positioning. Experiments were conducted for the position analysis and the angular tilt of the mobile platform along x-axis and y-axis and they were found by actuating the links of the manipulators. In order to confirm the results obtained by the experimental method, ADAMS was used for solving the kinematic problems involved. The Tri-Glide and Tripod manipulators were created in ADAMS based on the fabricated models. The models were simulated for the displacement of the nut and the angle of tilt / rotation of the mobile platform about the x and y axes. The results obtained by the three methods are discussed and analyzed. In a conventional drilling machine, drilling an angular hole requires special fixtures for each specific angle. In the present work, the parallel manipulator mechanisms have been modified to an angular drilling machine, for performing angular drilling operations. (C) 2014 The Authors. Published by Elsevier Ltd.