Session: 06-07 Adaptive Systems in Robotics and Control

Paper Number: 165318

165318 - Bio-Inspired Soft-Gripping System Utilizing Shape Memory Alloys for Precise Manipulation of Fragile Objects 

This paper delves into the development of a bio-inspired soft-gripping system optimized for handling fragile objects. Conventional pneumatic or hydraulic grippers, as well as state-of-the-art soft grippers such as FESTO adaptive shape gripper DHEF - chameleon tongue gripper [1], jelly-fish inspired gentle grippers [2], and dielectric elastomer-based grippers [3], often suffer from bulkiness, dependency on external sensors, and inadequate object contact, leading to inefficient manipulation of delicate items. To address these limitations, the proposed system integrates the Fin Ray Effect (FRE) and Shape Memory Alloy (SMA), enhancing both the adaptability and gripping efficiency.

The FRE gripper, inspired by the fish fin rays, conforms to diverse object shapes, maximizing contact area and distributing gripping forces effectively. This reduces the necessary applied force, thereby minimizing the risk of damage to fragile items. The inclusion of optimally placed SMA actuator wires, as previously investigated [4], introduces a compact and intelligent actuation mechanism. SMA wires exhibit shape-memory properties, contracting upon heating and eliminating the need for bulky mechanical components. Additionally, their intrinsic self-sensing capability enables real-time force and contact detection without external sensors, simplifying the system and improving reliability.

The proposed gripper system consists of a lightweight, single-body soft gripper with three FRE fingers. enhancing adaptability and dexterity. A bistable actuator is incorporated to improve energy efficiency, maintaining grip states without continuous power input [5]. This feature significantly reduces power consumption, a common challenge in conventional grippers. Moreover, the integration of SMA actuators with self-sensing capabilities positions this gripper as a viable solution for Industry 4.0 applications, where autonomous functionality and energy efficiency are critical.

Building upon prior research on SMA wire placement and FRE gripper design optimization, this study presents the fully developed gripping system and its comprehensive characterization. The system’s performance is evaluated for manipulating fragile objects such as an egg or strawberry (gripper payload ≈ 10 - 60 g, length ≈ 25 - 50 mm,  diameter ≈ 10 - 50 mm). Key performance metrics include real-time self-sensing behavior of the SMA actuator wires, dexterity, load capacity and object handling efficiency. By advancing SMA technology integration in bio-inspired soft robotics, this research contributes to developing compact, adaptive, and smart gripping solutions for delicate object manipulation. Potential applications extend beyond industrial automation to sectors such as healthcare, agriculture, and precision assembly, where gentle yet effective handling is essential.

References:

[1]  FESTO Adaptive shape gripper DHEF, Available at: https://press.festo.com/en/technologies-and-products-1/the-automated-chameleon-tongue (Accessed: 10 March 2025)

[2]  Nina R. Sinatra, “Ultragentle manipulation of delicate structures using a soft robotic gripper”. Sci. Robot.4, (2019), eaax5425, doi: 10.1126/scirobotics.aax5425

[3]  Yaguang Guo, Liwu Liu, Yanju Liu, Jinsong Leng, “Review of Dielectric Elastomer Actuators and Their Applications in Soft Robots”, Advanced Intelligent Systems, vol. 3, issue 10, 2021, p. 2000282, doi: 10.1002/aisy.202000282.

[4]  S. A. Sivakumar, Y. Goergen, T. Gorges, G. Rizzello and P. Motzki, "Innovative Fin Ray gripper with integrated SMA actuator wires," ACTUATOR 2024; International Conference and Exhibition on New Actuator Systems and Applications, Wiesbaden, Germany, 2024, pp. 72-75

[5]  Scholtes, D, Seelecke, S, Rizzello, and Motzki, P. "Design of a Compliant Industrial Gripper Driven by a Bistable Shape Memory Alloy Actuator", Proceedings of the ASME 2020 Conference on Smart Materials, Adaptive Structures and Intelligent Systems. ASME 2020 Conference on Smart Materials, Adaptive Structures and Intelligent Systems. Virtual, online. September 15, 2020, V001T04A001, ASME, doi: 10.1115/SMASIS2020-2204

Presenting Author: Shivaani Anitha Sivakumar Saarland University

Presenting Author Biography: Shivaani is a Research Associate at Saarland University and ZeMA (Centre for Mechatronics and Automation). She holds a bachelor's degree in Mechatronics Engineering and a master's degree in Embedded Systems. As a mechatronics engineer, she has worked on developing smart actuators and designing human-robot interaction systems for diverse applications. Currently, her research focuses on soft robotics using shape memory alloy actuators. Her interests include soft robotics, human-robot interaction, haptics, and wearable technology, driven by their multidisciplinary nature.