Evaluation of linear and revolute underactuated grippers for steel foundry operations

Purpose – The purpose of this paper is to develop an automated industrial robotic system for handling steel castings of various sizes and shapes in a foundry. Design/methodology/approach – The authors first designed a prismatic gripper for pick-and-place operations that incorporates underactuated passive hydraulic contact (PHC) phalanges that enable the gripper to easily adapt to different casting shapes. The authors then optimized the gripper parameters and compared it to an adaptive revolute gripper using two methods: a planar physics based quasistatic simulation that accounts for object dynamics and validation using physical prototypes on a physical robot. Findings – Through simulation, the authors found that an optimized PHC gripper improves grasp performance by 12 per cent when compared to an human-chosen PHC configuration and 60 per cent when compared to the BarrettHand™. Physical testing validated this finding with an improvement of 11 per cent and 280 per cent, respectively. Originality/value – This paper presents for the first time optimized prismatic grippers which passively adapt to an object shape in grasping tasks.