Universal Gripper Research Articles

Case Study of KIMM Universal Gripper: Analysis of Commercial Industrial Gripper and Evaluation of the KIMM Universal Gripper in Industry

The need for automation in manufacturing processes has created a demand for flexible production systems that can easily adapt to changing market needs. However, due to limitations in gripper performance, manual labor is still required in many manufacturing processes, especially when handling different objects. This paper proposes a classification of grippers used in the industrial field and analyzes the characteristics of each gripper category. The effectiveness of gripping and handling objects depends on the type of gripper used, making it challenging to find a gripper that can handle a wider range of objects beyond the typical boundaries. To address this issue, we describe two universal grippers developed by KIMM: the Impactive-type universal gripper and the Astrictivetype universal gripper. We also discuss the limitations of each gripper as discovered during their implementation in industrial applications and present research on overcoming these limitations. Additionally, we introduce two types of hybrid universal grippers as possible solutions to cover a broader range of fields. By analyzing these grippers, we provide predictions for the future development of grippers, which align with KIMM's ongoing research and development efforts.

A 3D Printing‐Enabled Artificially Innervated Smart Soft Gripper with Variable Joint Stiffness

AbstractThe manufacturing industry has witnessed advancements in soft robotics, specifically in robotic grippers for handling fragile or irregular objects. However, challenges remain in balancing shape compliance, structural rigidity, weight, and sensor integration. To address these limitations, a 3D‐printed multimaterial gripper design is proposed. This approach utilizes a single, nearly fully automated 3D printing process to create a universal gripper with almost no assembly work. By processing functional polymer, polymer nanocomposite, and metal wire simultaneously, this technique enables multifunctionality. The gripper achieves different gripping configurations by adjusting joint stiffness through Joule heating of conductive polylactic acid material, ensuring shape conformance. Embedded metal wires, created using an in‐house wire embedding technique, form reliable high‐current‐loading interconnections for the conductive joints acting as the heater. Additionally, an integrated soft sensor printed in thermoplastic polyurethane (TPU) and conductive TPU detects compression levels and discerns handled samples. This study showcases the potential of 3D multimaterial printing for on‐demand fabrication of a smart universal gripper with variable stiffness and integrated sensors, benefiting the automation industry. Overall, this work presents an effective strategy for designing and fabricating integrated multifunctional structures using soft, rigid, and conductive materials, such as polymer, polymer nanocomposite, and metal through multimaterial 3D printing.

Self‐Regulated Self‐Healing Robotic Gripper for Resilient and Adaptive Grasping

Flexible, soft materials are increasingly used for the fabrication of soft robots, as the inherent compliance and shock‐absorbance protect the robot from mechanical impact. Soft universal grippers take full advantage of this adaptability, facilitating effective and safe grasping of various objects. However, due to their predominantly soft material composition, these grippers have limited lifetimes, especially when operating in unstructured and unfamiliar environments. The self‐healing universal gripper (SHUG) is proposed, which can grasp various objects and recover from substantial realistic damages autonomously. It integrates damage detection, heat‐assisted healing, and healing evaluation. Notably, unlike other universal grippers, the entire SHUG can be fully reprocessed and recycled. The gripper's functionality relies on the particle jamming of steel balls enclosed within a self‐healing membrane. Thanks to the thermoreversible covalent Diels–Alder bonds in self‐healing polymer membrane, the gripper is able to recover from macroscopic damages including scratches and punctures. Temperature‐assisted healing is regulated in a closed‐loop manner using an embedded thermocouple and Joule heater. Experimental validation demonstrates the adaptability, resilience, and recyclability of the SHUG.

A Palm-Shape Variable-Stiffness Gripper Based on 3D-Printed Fabric Jamming

Soft grippers have excellent adaptability for a variety of objects and tasks. Jamming-based variable stiffness materials can further increase soft grippers' gripping force and capacity. Previous universal grippers enabled by granular jamming have shown great capability of handling objects with various shapes and weight. However, they require a large pushing force on the object during gripping, which is not suitable for very soft or free-hanging objects. In this paper, we create a novel palm-shape anthropomorphic variable-stiffness gripper enabled by jamming of 3D printed fabrics. This gripper is conformable and gentle to objects with different shapes, requires little pushing force, and increases gripping strength only when necessary. We present the design, fabrication and performance of this gripper and tested its conformability and gripping capacity. Our design utilizes soft pneumatic actuators to drive two wide palms to enclose objects, thanks to the excellent conformability of the structured fabrics. While the pinch force is low, the palm can significantly increase stiffness to lift heavy objects with a maximum gripping force of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$17\,$</tex-math></inline-formula> N and grip-to-pinch force ratio of 42. We also explore different variable-stiffness materials in the gripper, including sheets for layer jamming, to compare their performances. We conduct gripping tests on standard objects and daily items to show the great capacity of our gripper design.

Investigation of Fluidic Universal Gripper for Delicate Object Manipulation.

The compliance of conventional granular jamming universal grippers is limited due to the increasing friction among particles when enveloping an object. This property limits the applications of such grippers. In this paper, we propose a fluidic-based approach for universal gripper which has a much higher compliance compared to conventional granular jamming universal grippers. The fluid is made of micro-particles suspended in liquid. Jamming transition of the dense granular suspension fluid from a fluid (hydrodynamic interactions) to solid-like state (frictional contacts) in the gripper is achieved by external pressure from the inflation of an airbag. The basic jamming mechanism and theoretical analysis of the proposed fluid is investigated, and a prototype universal gripper based on the fluid is developed. The proposed universal gripper exhibits advantageous compliance and grasping robustness in sample grasping of delicate objects, such as plants and sponge objects, where the traditional granular jamming universal gripper fails.

Versatile end effector for laparoscopic robotic scrub nurse

PurposeIntegrating robotic scrub nurses in the operating room has the potential to help overcome staff shortages and limited use of available operating capacities in hospitals. Existing approaches of robotic scrub nurses are mainly focused on open surgical procedures, neglecting laparoscopic procedures. Laparoscopic interventions offer great potential for the context-sensitive integration of robotic systems due to possible standardization. However, the first step is to ensure the safe manipulation of laparoscopic instruments.MethodsA robotic platform with a universal gripper system was designed to pick up and place laparoscopic as well as da Vinci^{circledR } instruments in an efficient workflow. The robustness of the gripper system was studied using a test protocol, which included a force absorption test to determine the operational safety limits of the design and a grip test to determine the system performance.ResultsThe test protocol shows results regarding force and torque absorption capabilities of the end effector, which are essential when transferring an instrument to the surgeon to enable a robust handover. The grip tests show that the laparoscopic instruments can be safely picked up, manipulated and returned independent of unexpected positional deviations. The gripper system also enables the manipulation of da Vinci^{circledR } instruments, opening the door for robot–robot interaction.ConclusionOur evaluation tests have shown that our robotic scrub nurse with the universal gripper system can safely and robustly manipulate laparoscopic and da Vinci^{circledR } instruments. The system design will continue with the integration of context-sensitive capabilities.

Design of a Liquid Jamming Gripper

We present the design of a universal gripper based on the principle of liquid jamming. The phase change behavior of a mineral oil subjected to cooling is used for adaptive gripping and release of objects. The mineral oil is enclosed in a soft, compliant membrane molded into a spherical shape. The membrane with the liquid easily adapts to the shape of the object to be picked up. A thermoelectric cooling system is designed with a conductive spreader immersed in the oil to quickly cool the liquid held in a membrane. Once the membrane gripper conforms to the shape of the object partially enclosing it, the liquid is cooled below the phase change temperature, thus freezing the liquid and hardening the gripper around the object and effectively gripping it. We describe the design methodology of the gripper, part selection, and mechanical design. A proprietary controller developed by Venture Corporation is used for controlling the TEC module and the controller is based on a simple PID optimized using Ziegler–Nichols tuning for the P, I, and D values. The hardware is evaluated and the basic gripping functions on different odd-shaped objects are demonstrated. An invention disclosure has been submitted to the NUS IP office (ILO).

Robot-assisted automated sorting techniques for plastic recycling

This report discusses the current state of the art of robot-assisted sorting and separation systems in waste processing for the recovery of recyclable materials. The sorting methods addressed here are limited to the waste disposed of by households and include the sorting of pre-sorted municipal waste, e. g. plastic sorting. The focus is on the challenges of proven material recovery facilities and why manual sorting is still a necessity for efficient waste sorting. Solutions are sought to eliminate the employment of humans partially or completely for waste sorting. Suitable gripping components are to be found since one of the biggest challenges in waste sorting is gripping objects with different shapes, sizes, weights, positions, and materials. Not only existing techniques in the waste industry are addressed, but a broad spectrum is searched for possible universal grippers. This paper aims to provide a comprehensive overview of the state-of-the-art robotic systems in the waste industry and presents different types of grippers that can lead to a possible solution to the described challenge. Through an evaluation system, the presented grippers were compared, revealing that the combination of individual gripping mechanisms is promising for waste handling. Furthermore, it was found that sufficient degrees of freedom in the wrist area of a robotic arm can facilitate better gripping quality.

USE OF THE OMRON F150-3 CAMERA FOR THE POSITIONING OF RANDOMLY DISTRIBUTED PARTS

The article discusses the development of a testing workplace for the handling of 3D objects. The workplace is equipped with an industrial SCARA robot, an intelligent input conveyor, pallet and depalletizing equipment, a vibrating feeder and vibrating trays, switch effectors, universal gripper, and other components. The workplace is also equipped with two OMRON F150-S1 cameras, which are used to create a 3D camera system. The article describes how the 3D camera system is used to determine the position of objects on the conveyor belt. The system first uses the density averaging function to determine the average optical density of the region without any objects. This value is then used as a threshold to determine whether an object is present in the workspace. If an object is present, the system uses the gravity and area functions to calculate the X and Y coordinates of the object from the center of the measuring platform. The system then uses the edge position function to calculate the Z coordinate of the object

Utilization of Magnetically Induced Jamming in a Novel Soft Robotic Gripper

Today’s high-tech society creates a pressing need for advanced medical prosthetics and industrial grippers. However, as technological advancements continue to be incorporated, a gap is created by the quality–cost ratio associated with using technologically advanced solutions. For example, many open-source prosthetics provide relatively inexpensive devices, but they often sacrifice the ability to grip irregularly shaped or smooth objects. For instance, doorknobs are difficult to grip using the typical hard robotics approach but can be gripped using soft robotic techniques. Prior work with soft robotics successfully used compressed air and a small granular material (coffee grounds) to build a gripper that can hold various objects. However, the use of compressed air makes these devices relatively slow, and the need for an air compressor limits the applicability of this design. Our primary goal was to explore the feasibility of a soft robotic approach that utilizes ferromagnetic granular materials to grip an object via the granular jamming transition that is induced with an external magnetic field. The granular material is placed inside flexible membranes made of polyisoprene, wherein the granular materials can go from a more relaxed state to a more rigid state depending on the strength of the magnetic field. The flexible membrane also allows the object to be held and then return to its original state when released. A solenoid provides a magnetic field that is easily turned on and off to jam and unjam the magnetic granular material and thus allows us to hold an object in place without the use of compressed air. In searching for a magnetic granular material, we found that iron filings work well, as they easily conform to the shape of the object. We have observed success in holding and releasing several smooth knobs as well as more angular shapes. This work will further the development of a low-cost but high- functioning universal gripper with applications in prosthetics and pick-and-place devices, as well as a multitude of industrial applications.

An Underactuated Universal Gripper: Design, Analysis, and Experiment

As the working tool of the robot, the importance of the gripper becomes more prominent with the extensive use of the robot. This paper proposes a new type of underactuated universal gripper that can be applied to handle lightweight parts of any shape. It integrates a crank train and a four-bar mechanism to grasp objects. The kinematics and statics analysis of the proposed gripper were carried out; and in this paper, we briefly introduce the concept and control system design. Then, the motion characteristics and grasping ability of the underactuated gripper are presented. A prototype of the gripper was designed and manufactured based on the simulation analysis, and relevant grasping experiments were carried out. The experimental results verify that the proposed universal gripper has the advantages of safe design, easy manufacturing, effective gripping, and stable holding of objects.

Bionic design of universal gripper for nursing robot with hybrid joints and variable Equivalent Link Length

Currently, most rehabilitation/nursing robots attach the human body to the end of the robot by ‘binding’ solution, which makes the operation complicated and greatly limits their applications. Therefore, it is necessary to study a universal gripper that can directly grasp human limbs as the end-effector of the robot. Inspired by the human hand, this paper proposes a bionic under-actuated gripper that imitates the structure of human hand. The concept of Equivalent Link Length (ELL) is proposed to optimize the envelope effect. And the structure with hybrid rotational and translational joints is proposed to increase gripping stiffness and to avoid the harmful component in the grip force. Theoretical analyses and experiments on envelope effect, force distribution and load capacity show that the propose gripper can grasp cylindrical (limb-shaped) objects with wide applicable size range, and also has a high load capacity. Furthermore, the gripper has the characteristic of almost constant force transfer ratio, which reduces the number of sensors required by the system. These results show that the gripper has the potential to be used in the nursing robot system.

A SYSTEMATIC REVIEW ON PNEUMATIC GRIPPING DEVICES FOR INDUSTRIAL ROBOTS

Based on the literature review, the article presents the analysis of approaches to classifying Gripping Devices (GDs) of Industrial Robots (IRs) and substantiates the need for systematising Pneumatic GDs (PGDs). The authors propose a classification of well-known PGDs, in which the holding force of the Manipulated Object (MO) is formed under the action of gas-dynamic effects. A general classification of PGDs with features common to all PGD subtypes is proposed: PGD type; contact type; object base type; object centring type; specialisation type; working range; availability of additional devices; the number of grippers; type of control; type of attachment to the robot. Each feature of the general PGD classification, which affects PGD characteristics, is analysed, and a usage example is given. The advantages of each feature included in the general PGD classification are also considered. For a more detailed classification, PGDs are divided into the following types: Vacuum GDs (VGDs), Jet GDs (JGDs), Combined PGDs (CPGDs). For VGD, the main distinguishing features are highlighted, which are the vacuum creation method, effect/actuator, stepwise nozzle, suction cup type, suction material type. The main distinguishing features of JGDs include using a jet of compressed air, the shape of nozzle elements, the number of nozzle elements, the direction of gas flows, type of surface of the MO. The main distinguishing features of CPGD include the type of combination and function performed. The main features are given for each classification, and the advantages/disadvantages of the most typical representatives of GDs are described. The authors identify the main development directions for GDs at the present stage of robotisation of production processes, medicine, military and space technology, etc. Based on the analysis and systematisation of literature data, the authors define the main promising areas of research that will be actively developed soon: optimisation of grippers’ design, flexible grippers, additive manufacturing (3D-printing) when creating grippers, collaborative grippers, modular grippers, universal grippers, grippers based on new materials, new effects in grippers, bionic and medical grippers, simulation and rendering of the gripping process.

Fin Ray gripper for handling of high temperature hybrid forging objects

Universal handling systems are getting more and more relevant nowadays. Their unique ability to adapt to different objects and their various shapes enable cost savings by minimizing the number of handling systems and reducing set-up times. Furthermore, the mentioned aspects are advantageous for the hybrid forging manufacturing process, where the objects change their geometry several times. However, this work deals with the discrepancy between universal gripper, consisting mostly of polymer materials and the high temperature of the forging objects. Universal grippers are predominantly made of monolithic elastic material to achieve high functionality. However, the material has the disadvantage of only being applicable in a small temperature range, whereby the forging process reaches temperatures of up to 1200 °C. One type of monolithic grippers are so called Fin Ray grippers that use fingers based on the Fin Ray effect to close around objects when they encounter them. This adjustment takes place passively, requiring a minimum of actuation, which is advantageous for use at high temperatures. Therefore, we have designed a Fin Ray finger made of heat-resistant bulk material to close the mentioned gap. Our design consists of rigid links connected with joints providing shape variability. The thermal condition was taken into account as the temperature of the objects reaches up to 1200 °C. Thereby, temperature-related effects occur, such as thermal expansion, which strongly influence the design of the finger. To investigate this, a thermal simulation is used. Furthermore, an investigation of the adaptability is carried out based on a multi-body FEM simulation. In this process, the finger is specified in an iterative process based on hybrid demonstrator components.

A Sea-Anemone-Inspired, Multifunctional, Bistable Gripper.

The growing need for soft robots with secure, adaptive, and autonomous functioning in unforeseen environments favors designs with multiple functionalities. This has driven soft robotic grippers to be explored to integrate perceptual capability for augmented multifunctionality. In nature, sea anemones can detect and catch preys of various shapes and sizes effectively with extremely simple bodies because of the efficient coupling of sensing and actuation capability. Inspired by their body structures, we present a bistable gripper with multifunctionality that includes sensing (proprioceptive and exteroceptive) and multimodal gripping (grasping and pinching). The gripper exploits an array of tapered pins on the external surface of a dome membrane for gripping and a set of cylindrical markers on the internal surface of the membrane for optical sensing. The membrane is bistable and can settle in either of two equilibrium states "natural" and "retracted." Gripping functionality is achieved by the centripetal enveloping movement of the pins, along with the passive snap-through process of the membrane. By analyzing the distribution of markers within the view of an embedded camera, sophisticated sensing functionality can be achieved. We first characterized each function separately and then implemented an object handling system, combining the sensing and gripping functionality, to demonstrate the potential for more advanced robotic applications. This work delivers a compact universal gripper design with an efficient and elegant integration of multifunctionality.

Modeling and analysis of a passively adaptive soft gripper with the bio-inspired compliant mechanism

Similar to the end effectors for traditional rigid robots, those for soft robots are essential as the interacting media between the robots and their environments. Inspired by the forelegs of climbing animals, a passively adaptive soft gripper (ASG), with six claws and a compliant mechanism, is developed for grasping objects and attaching to rough surfaces. The design method, grasp adaptability, form closure, and force equilibrium of the ASG are presented and analyzed in this paper. Due to the compliance at each claw root, the ASG possesses a high passive adaption to various objects. With sharp hooks, a form closure may be achieved easily when the ASG grasps rough objects with structured or unstructured shapes. The ASG grasping an object constitutes an under-actuated system, the solution to which is difficult to obtain. The Monte Carlo method is suggested to achieve effective solutions for such systems, and the in-hull rate is proposed to evaluate the difficulty of finding solution. Tests and experiments with the ASG grasping various objects have verified the adaptability and reliability of the ASG. The analytic and experimental results show that the novel ASG may be used as a universal gripper for soft manipulators and a prospective attaching device for biped climbing soft robots.

Soft Robotic Palm With Tunable Stiffness Using Dual-Layered Particle Jamming Mechanism

This article presents a novel robotic palm with a dual-layered structure designed to yield high surface conformity and controllable rigidity for enhanced grasping performance. It comprises a vacuum chamber for adjusting the stiffness of the palm via particle jamming and an air chamber for actively controlling the palm deformation. An auto-jamming control scheme that automatically solidifies the palm by sensing the internal pressure of the palm without any tactile sensors or visual feedback was also proposed. Given the design and control of the robotic palm, the performance of the dual-layered jamming mechanism was characterized in terms of shape adaptability and stiffness controllability. The contact surface areas increased by 180&#x0025; compared with the single-layered robotic palm, and the adjustable stiffness was within a range of 0.20&#x2013;2.53&#x00A0;N&#x002F;mm for varying vacuum pressures. Moreover, the palm can act as a universal gripper for small objects, yielding a holding force of up to 13.9 N. The grasping performance of the palm in conjunction with robot fingers was evaluated for various objects for varying palm stiffness. The palm increases the grasping force by 2.0&#x2013;3.1 times compared with flat skin. Multimodal grasping strategies for various objects were demonstrated by manipulating a robot arm.

Enhancing the Universality of a Pneumatic Gripper via Continuously Adjustable Initial Grasp Postures

Recently, various soft universal grippers have been developed due to their reduced control complexity and satisfying grasping capability. The gripping range of a gripper plays a key role in its universality. This article presents a pneumatically actuated soft-rigid hybrid multifinger gripper that has a wide gripping range by adjusting its initial grasp postures. The gripper is compact (dimensions: <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$\text{100} \times \text{60} \times \text{170}$</tex-math></inline-formula> mm), lightweight (weight: 380 g), and modular. It consists of four modules, with each module containing three pneumatic actuators (a distance-adjusting actuator, an angle-adjusting actuator, and a finger actuator) and rigid connectors. Through initial grasp posture adjustment, and fingers with tapered angles to generate nonconstant bending while grasping, the gripper can grasp objects of a wide variety of sizes and weights, thus increasing its universality. The gripper is tested to characterize its distance adjustment range, angle adjustment range, and stiffnesses in load-bearing directions, at continuously changing pneumatic pressures. The distance adjustment range and angle adjustment range of the gripper are 0–64.4 mm (64.4% of the initial gripper length) and 0 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$^{\circ}$</tex-math></inline-formula> –140 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$^{\circ}$</tex-math></inline-formula> , respectively. The maximum stiffnesses of distance-adjusting actuator and angle-adjusting actuator are 3331 and 1.15 N <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$\cdot$</tex-math></inline-formula> m/rad, respectively. Finally, grasping experiments show that our gripper can successfully grasp objects with diameters ranging from 0.5 to 180 mm, lengths ranging from 10 to 325 mm, and the heaviest object it can grasp is 2.1 kg (more than five folds of its own weight). The results demonstrated that our pneumatic gripper has an increased gripping range without adding other types of energy sources and its enhanced universality will expedite various applications in daily life and industry.

Design and Analysis of Universal Gripper for Robotics Applications

A universal gripper is a component that consists of fine dust material enclosed in fine rubbery membrane for holding and assembly. The gripper is especially applied for quickly gripping and discharging large number of objects having complex geometries in wide applications. The objects which are in various shapes and different geometries are difficult to grasp which confirms that it is not suitable for apply in various pick and place operations. In this project, a low cost modular gripper is implemented with suitable mechanical design, structural analysis and real time analysis. In this association, the designed gripper can hold many parts and place it at once while sustaining relative distance and relative coordination at their state. The universal gripper acts as a vacuum tube to grip the object it needs to relocate. This universal gripper can hold various objects such as eggs, grocery items, industrial components, heavy objects etc., therefore, a selected experimental setup has been developed with the composition of shapeless gripper and perform simulation in holding of the different items. Results of the tests and experiments shows the proposed Universal Gripper are validated with feasibility options.

Gripper Finger Design for Special Purpose Applications

The trend towards collaborative robots is resulting in these "machine workers" working alongside humans in many workplaces. They can be used for a wide range of tasks and, most importantly, can rapidly switch between tasks. When it is no longer necessary for them to work at one location, they can simply be transferred to support another production process. With their universal gripper they can handle a wide range of tasks, however, custom accessories may need to be produced in specific areas. One such accessory could be sleeves that are mounted on the grippers to extend the use of the universal gripper. This paper aims to provide assistance on how to design these fingers.