Preliminary Study on Multibody Modeling and Simulation of an Underactuated Gripper With Differential Transmission

Abstract

Robotic grippers have represented a challenge for designers and engineers since at least three decades, due to the complexity of grasping and manipulation tasks. Underactuated and soft robotic grippers are a technology that allows good dexterity and manipulating capabilities, by reducing the number of actuators. However, this type of device requires the use of complex mechanical systems to compensate the underactuated implementation limits, such as differential mechanisms. The differential mechanism is necessary to decouple finger closures and distribute forces. The multibody simulation allows to evaluate the main parameters of the elements to understand how the differential system can work. The development and design of complex mechanical systems is simplified by this technique. In particular, this paper presents a multibody simulation analysis which recreates an elementary model of a gripper with two links and a single actuator; the developed model reproduces the grasping of an object using a mechanical differential pulley system, placed beneath the fingers. Some results are presented to study the role of the differential when the fingers grasp an object with different configurations. The aim of this work is to show how an accurate and still manageable multibody model integrated in Matlab environment is able to extend the classical grasp metrics to a more general dynamic setup.

Modeling and Simulation of Robotic Grasping in Simulink Through Simscape Multibody

“…As previously introduced, multibody simulation aims at solving the kinematic and dynamic problems of mechanical systems, and is particularly useful to study the behaviour of complex mechanical and robotic systems like grippers and manipulators ( Achilli et al, 2021a ).…”

“…The multibody simulation of mechanical systems is widely used in mechanical engineering for solving the mechanism’s kinematic and dynamic problems. Applications range from mechanical components ( Logozzo and Valigi, 2019 ), to mechanisms ( Valigi et al, 2020a ) and robots ( Achilli et al, 2021a ; Zhu et al, 2022 ). The multibody model of a mechanical system is composed of rigid and deformable bodies, interconnected by means of kinematic pairs.…”

Characterization of finger joints with underactuated modular structure

“…Some recent development further exploits Interpenetrating Phase Composites [13] and topology optimization techniques for obtaining a multimaterial-like behaviour varying the 3D printing infill density [14,15]. A proper mechanical characterisation is very important to predict the dynamic behaviour of the soft robotic component [16]. This work is focused on the mechanical characterisation of compliant joints of robotic modular fingers, providing methods and results that can be exploited in the design of new soft hands, improving dexterity [17].…”

Contact mechanics analysis of a soft robotic fingerpad

“…The main tasks performed by a gripper are grasping and manipulation of objects; for this reason, they are specialized structures with few sensors and characterized by simple kinematic structures. The most modern grippers are more and more similar to human hands (Bennett et al, 2015;Shintake et al, 2018;Ke et al, 2021), and their design varies from grippers with two parallel fingers, to those that replicate the anthropomorphism of the human hand with articulated fingers and palm (Achilli et al, 2020;Achilli et al, 2021;Achilli et al, 2022;Shorthose et al, 2022).…”