Development of a planar 3prp parallel manipulator using shape memory alloy spring based actuators

Abstract

This paper presents the development of a SMA (shape memory alloy) spring actuation based 3-dof (three degree of freedom) 3PRP (prismatic-rotary-prismatic) planar parallel manipulator where each limb (3 stands for three limbs) of the manipulator having PRP joint arrangement. The active prismatic actuators are made of SMA springs. This 3PRP planar parallel manipulator has a parallel structure including a fixed base and a moving platform (end-effector) and placed in xy plane. Base and the end-effector of the manipulator are linked together by three limbs consisting of prismatic-revolute-prismatic (PRP) joint arrangement in which each limb has one active prismatic joint made of SMA springs. Forward and inverse kinematic analysis of the 3PRP planar parallel manipulator has been studied. Suitability and usage of SMA spring based actuators replacing highly bulky prismatic actuators has been investigated. In addition, the detailed study of the actuation or deflection of the SMA springs in the application of driving the manipulator has been presented experimentally. From the experimental results, it is observed that the 3PRP manipulator associated with SMA spring based actuators has larger workspace to total area required ratio as all the three active prismatic actuators actuates properly and in same time. In overall, this paper shows the 3PRP planar parallel manipulator associated with SMA spring actuators is superior alternatives to conventional motion stages for high precise micro-positioning and tracking applications.