Finite Element Analysis of Soft Robotic Gripper For Pineapple Harvesting

Abstract

Nowadays, harvesting delicate and high-value fruits, vegetables, and edible fungi requires a large input of manual human labour. Robotic systems that selectively harvest crops are being developed. Robotic grippers serve as the fundamental “hand” of robots, providing critical grasping and manipulation functions. Typically, these grippers employ mechanical, electrical, or other power sources to switch between grasping and releasing modes. To execute successful grasps, robotic grippers must exhibit precision in their gripping actions to prevent slippage and damage, as well as adapt their grasping strategies spontaneously based on the object characteristics. While rigid robots excel in executing repetitive tasks along assembly lines, their interactions with delicate objects remain a safety concern due to the lack of flexibility in their links, joints, and structures. Therefore it paved the way for the development of soft robotic grippers. The project has been carried out to develop a soft robotic pineapple gripper with the following objectives. To study fruit parameters towards the development of soft robotic pineapple grippers, to design soft robotic pineapple gripper and the geometry and material optimisation of soft robotic pineapple gripper. Physical and mechanical properties of pineapple assessed by evaluating fruit parameters such as shape, size, length, diameters, weight and firmness which were then used for the design of soft robotic pineapple gripper. Soft robotic pineapple gripper was designed by considering 5th to 95th percentile of all the measured physical and mechanical properties. Soft gripper has been developed using design/ CAD software – SolidWorks. Optimisation of soft gripper has been carried out by considering geometry (triangle, rectangle and half round), materials (Ecoflex-0030, Dragonskin 0030 and Smoothsil 950) at different pressures using finite element analysis of soft grippers with the help of ANSYS workbench R2. From the three hyper-elastic materials and geometries, Dragon skin 30 with triangle geometry is best for fabricating soft grippers in terms of bending angle and experienced stress. For future work, similar soft grippers can be developed experimentally and their performance can be compared practically.