Development and performance investigations of the planar parallel robotic manipulators using shape memory alloy linear actuation technique

Abstract

Planar parallel manipulators (PPMs) have the capability to manipulate only on a single Cartesian plane. The application of PPMs in various fields increases due to their lower inertia, higher stiffness, and accuracy. Shape memory alloy spring (SMAS) based linear actuators may be the alternative option for the linear actuators compared to the servo motor, ball screw, and bulky actuators. This paper presents the development of SMAS linear actuation-based three degrees of freedom U-shape fixed base planar parallel manipulator and investigates the workspace and trajectory tracing ability of the proposed manipulators. The manipulators are composed of three legs, where the first prismatic joint of each leg is the active prismatic joint (SMAS). The present study proposes numerical modelling of the three manipulators, namely 3-PRP (C1), 1-PRR-2-PRP (C2), and 1-PPR 2-PRP (C3), where P denotes an active prismatic joint, P represents a passive prismatic joint, and R indicates a revolute joint. The results of this research work were validated with the experimental one. It was found that the manipulator's obtained workspace is almost the same as the workspace obtained through experimental results. The loss of workspace area (minor) is due to heat dissipation, friction between the links, singularities, passive links, stiffness, force distribution, etc. This study also investigates the trajectory-tracing capability of the proposed manipulators. The importance of SMA-based actuators over conventional prismatic actuators has been discussed. The PRR-PRP-PRP manipulator possesses the highest workspace as compared to the other manipulators. This work claims that due to the good numerical analysis results with the experimental one, it is acceptable to do the numerical analysis as it is validated to reduce the cost of making different practical systems for trials.