A Comparative Study of Different Fingertips on the Object Pulling Forces in Robotic Gripper Jaws

This paper presents a comparative study of the use of different fingertips in robotic gripper jaws with respect to measuring the pulling force of selected shaped objects from their grasp. The authors built a dedicated test stand and provided methodology to evaluate it. The authors' innovative approach was to design accessory-controlled jaws for the base of the Robotiq 2F-140 gripper. For the study, rigid structures-flexible soft cushions filled with air and magnetorheological fluid (MRF)-were developed for the jaw. In this way, comparable measurement results were obtained in terms of the structure of the gripper set-up. The secondary purpose of the study was to demonstrate the potential of the soft cushions that are adaptable to the shape of a gripped object. As a result, an adaptive structure was obtained that allows object pulling forces that are comparable to rigid fingertips. In doing so, this does not damage the surface of any of the interacting components. The cushions were made of thermoplastic polyurethane (TPU) formed using 3D printing technology. The results obtained during the implementation of this research may be beneficial for comparing gripper capabilities; thus, they can contribute to advances in smart devices and many industrial fields, including robotics and bioengineering.