In soft robotics, gripper technology based on granular jamming offers the capability to adapt flexibly to objects of diverse shapes and material properties. Specifically, small-scale jamming grippers can address tasks challenging for conventional grippers either by enhancing gripping performance or by extending functionality when combined with rigid grippers. This study investigated effects of membrane morphology, thickness, and material on performances of small-scale jamming grippers to identify optimal design parameters. Experiments were conducted with three membrane morphologies, two thickness levels, and two material types. Results indicated that a concentric-pocket membrane morphology, a membrane thickness of 1.5 mm, and a soft material such as Dragon Skin 10 achieved a superior holding force of 430.7 gf. These findings indicate that softer materials can improve the membrane's ability to conform to objects, while increasing thickness can minimize deformation due to tensile forces, thereby enhancing gripping stability. Furthermore, experiments demonstrated that this configuration could enable the gripper to safely grasp objects of various shapes and perform additional tasks, such as rotating valves and handles, with effectiveness.
In recent years, significant progress has been made in functional soft materials, alongside advances in nano/micromanufacturing techniques, driving the evolution of soft grippers to the forefront of robotics innovation. Compared to their traditional rigid counterparts, soft grippers offer unparalleled adaptability, effortlessly conforming to objects of varying sizes and shapes. This comprehensive review explores the latest trends shaping the landscape of soft robotic grippers, providing insights into their diverse functionalities and applications. The exploration begins with an examination of the various actuation mechanisms utilized by soft grippers, including cable or tendon-driven, pneumatic, electroactive, and thermoactive systems. Additionally, the review delves into the intricacies of grasping and manipulating mechanisms, spanning from multi-finger configurations to innovative approaches, such as jamming, suction, and adhesion grasping. Notably, hybrid grippers, which integrate multiple actuation and grasping mechanisms, are of particular interest, thereby enhancing the range of functionalities offered by these grippers. Finally, the review briefly addresses current limitations and future directions in the field.
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Soft autonomous mobile manipulators in agricultural automation – a review Tahsin Khan, Mervin Joe Thomas Industrial Robot: the international journal of robotics research and application.2025;[Epub] CrossRef
Soft robots, known for their flexible and gentle movements, have gained prominence in precision tasks and handling delicate objects. Most soft grippers developed thus far have relied on molding processes using high-elasticity rubber, which requires additional molds to produce new shapes, limiting design flexibility. To address this constraint, we present a novel approach of fabricating pneumatic soft grippers using thermoplastic polyurethanes (TPU) through the Fused Filament Fabrication (FFF) technique. The FFF technique enables the creation of various gripper shapes without the need for additional molds, allowing for enhanced design freedom. The soft grippers were designed to respond to applied air pressure, enabling controlled bending actions. To evaluate their performance, we conducted quantitative measurements of the gripper’s shape deformation under different air pressure conditions. Moreover, force measurements were performed during gripper operation by varying the applied air pressure and adjusting the mounting angle. The results of this study provide valuable insights into the design and control of soft grippers fabricated using TPU and the FFF process. This approach offers promising opportunities for employing soft robots in various fields and paves the way for further advancements in robotics technology.
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Heated Syringe Extrusion for Soft Gripper Fabrication in Additive Manufacturing Kwang Yeol Yu, Woo Jin Jeong, In Hwan Lee International Journal of Precision Engineering and Manufacturing-Smart Technology.2025; 3(1): 59. CrossRef
Multi-material additive manufacturing process design of sensor embedded soft gripper Kwang Yeol Yu, Hochan Kim, In Hwan Lee Sensors and Actuators A: Physical.2025; 386: 116322. CrossRef
Application of Image Recognition Technology in Nozzle Cleaning for Material Extrusion Additive Manufacturing Processes Ho-Chan Kim, Yong-Hwan Bae, Hae-Yong Yun, In-Hwan Lee Journal of the Korean Society of Manufacturing Process Engineers.2024; 23(11): 20. CrossRef
Construction of a Pneumatic Control System for Soft Gripper Seongyeon Kim, Kiseong Kim, Jongho Shin, Jungho Cho Journal of the Korean Society of Manufacturing Process Engineers.2024; 23(6): 30. CrossRef
This paper describes the control method of an electric gripper using a current control system. A current control system was designed and fabricated, and it consisted of a current sensor, an amplifier, and a precision voltage regulator. As a result of calibration by applying the current control system to the electric gripper, the error was less than ±0.34%. The proportional gain for the PI control of the gripper was 0.41, and the integral gain was 0.01. As a result of the control characteristics test, the arrival time was 0.79 s and the steady-state error was ±5 mV (±0.025 N). As a result of the experiment of holding the object, the gripper was able to hold the object safely. Therefore, the electric gripper applied using the current control system performed excellently in current control based on the reference force (grabbing force); thus, it is judged that it can be used to safely grip various objects in various fields.
In this paper, we describe the development of a 5-axis force/moment sensor of an intelligent gripper designed to grasp the weight of an unknown object and the position of the object in the gripper. The 5-axis force/moment sensor consists of an Fx force sensor, Fy force sensor, and Fz force sensor to measure weight, along with an Mx moment sensor and Mz moment sensor to determine the position of an object in the gripper. These sensors are all built within a single body. Each sensor sensing part of the 5-axis force/moment sensor was newly modeled and custom designed using software, and each sensor was manufactured by attaching a strain gauge. The results of the characteristic test of the fabricated 5-axis force/moment sensor showed that the rated output error was within 0.1%, the reproducibility error was within 0.05%, and the nonlinearity error was within 0.04%. Therefore, the 5-axis force/moment sensor developed in this paper can be attached to an intelligent gripper and be used to grasp the weight of an unknown object as well as the position of the object in the gripper.
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Design of a Three-Finger Gripper Capable of Gripping Irregular Objects Je-hyeon Kim, Gab-Soon Kim Journal of the Korean Society of Manufacturing Process Engineers.2023; 22(8): 41. CrossRef
In this study, we designed and manufactured a 3-axis force sensor for an intelligent gripper that safely grips an unknown object. The 3-axis force sensor consists of an Fx force sensor, an Fy force sensor, and an Fz force sensor in one body, and is manufactured by attaching a strain gauge. The characteristics evaluation showed that the rated output error was within 0.2, the nonlinearity error was within 0.05, and the reproducibility error was within 0.06%. Therefore, the 3-axis force sensor designed and manufactured in this study can be used to measure weight and control the force used to grip an unknown object by attaching it to the intelligent gripper.
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Control Method of Electric Gripper Using Current Control System Ji-Hye Min, Gab-Soon Kim Journal of the Korean Society for Precision Engineering.2023; 40(9): 725. CrossRef
Development of an Intelligent Gripper that Determines the Gripping Force According to the Weight of the Object Han-Sol Kim, Gab-Soon Kim International Journal of Precision Engineering and Manufacturing.2023; 24(12): 2259. CrossRef
In this paper, we designed and manufactured a new manipulator (less than 15 kg) to make the total weight of SCOBOT-200 (EOD robot: its platform weight is 35 kg) commercialized by FIRSTEC Co., Ltd. Link1 and Link2 of the manipulator were designed and fabricated using CFRP (Carbon Fiber Reinforced Plastics) material, and the other components were made of AL6061 material. The fabricated manipulator has 5-DOF, and the opening width of the gripper is more than 1520 mm. As a result of the characteristic test, the weight of manipulator is 14.5 kg, the length of the manipulator is 1500 mm, the payload when the manipulator extended is 8 kg, when folded is 20 kg. Thus, the manipulator manufactured can be used as a manipulator for a small EOD (Explosive Ordnance Disposal) robot.
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Research on the application of intelligent robots in explosive crime scenes Junwei Guo International Journal of System Assurance Engineering and Management.2023; 14(2): 626. CrossRef
Study on Output Characteristics of Printed Flexible Tactile Sensors Connected to Brass Terminals Jindong Kim, Yonghwan Bae, Inhwan Lee, Hochan Kim Journal of the Korean Society of Manufacturing Process Engineers.2020; 19(4): 65. CrossRef
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