Gripper System Research Articles

Prepatellar bursa mucosa: An unreported postoperative complication of patellar fracture.

Patellar fracture is a common injury caused by overstrain of the extensor mechanism or a direct trauma to the knee. The most common complications after patellar fracture are nonunion, infection, post-traumatic arthritis, joint fibrosis, symptomatic hardware, and extensor mechanism failure. These are attributed to the post-fracture flexion and extension movements, the primary damage to the articular cartilage, and the thin soft tissue coverage over the knee. To our knowledge, prepatellar bursa mucosa is an unreported postoperative complication of patellar fracture. We describe a case of a 58-year-old woman with a left patellar fracture from a fall. Complete healing was achieved after in 2 months postoperatively using the improved Kirschner wire tension band and a cable grip system; however, at 7 months postoperatively, a prepatellar skin mass appeared. The patient reported prepatellar discomfort with no pain and influence of movement of the knee and daily life. One year postoperatively, we surgically removed the implants and mass. The pathological result showed bursa mucosa. The literature review shows that pain, secondary knee dysfunction, fracture nonunion, and malunion are postoperative complications of patellar fractures. However, prepatellar bursa mucosa have not been previously reported as a postoperative complication. This case highlights the need for appropriate placement of the intraoperative implant in adults with patellar fractures.

Integration of Stacked Object Recognition and Robotic Arm Gripping System Utilizing Mask Region-based Convolutional Neural Network and Red–Green–Blue Depth Images

Integration of Stacked Object Recognition and Robotic Arm Gripping System Utilizing Mask Region-based Convolutional Neural Network and Red–Green–Blue Depth Images

Integrated Electromechanical Structure for Iontronic Pressure Sensors with Linear High‐Sensitivity Response and Robust Sensing Stability

AbstractA linear high‐sensitivity response is crucial for flexible electronic skin, particularly in precision detection for applications like intelligent robotics and human‐machine interactions. Prevailing strategies typically adopt a layered, multifaceted material design to cultivate this response, yet this approach often culminates in a diminished capacity to augment sensing stability. The root causes of these limitations are predominantly material mechanical mismatches and interface incompatibilities inherent in these designs. To address these challenges, an electromechanical integration strategy is introduced that simultaneously enhances linear highsensitivity and stability. This strategy is centered on constructing a robust, integrated mechanical and electrical interface within a polyurethane material system through an in situ growth and adhesion process. The iontronic pressure sensor exhibits a linear high‐sensitivity response (16.24 kPa−1, R2 = 0.999) within a wide range (0–300 kPa). Moreover, the sensor's integrated structure, self‐encapsulated through the adhesion between the electrode and dielectric layers, exhibits robust stability, even under complex mechanical stresses. The applications of the sensors in precision weighing and haptic feedback within intelligent gripping systems demonstrate their advantages of both linearity and stable sensing. This work delineates a strategic pathway for the fabrication of high‐performance flexible pressure sensors, contributing significantly to the field of advanced sensing technologies.

Development of a compliant gripper for safe robot-assisted trouser dressing-undressing

In recent years, many countries, including Japan, have rapidly aging populations, making the preservation of seniors' quality of life a significant concern. For elderly people with impaired physical abilities, support for toileting is one of the most important issues. This paper details the design, development, experimental assessment, and potential application of the gripper system, with a focus on the unique requirements and obstacles involved in aiding elderly or hemiplegic individuals in dressing and undressing trousers. The gripper we propose seeks to find the right balance between compliance and grasping forces, ensuring precise manipulation while maintaining a safe and compliant interaction with the users. The gripper's integration into a custom-built robotic manipulator system provides a comprehensive solution for assisting hemiplegic individuals in their dressing and undressing tasks. Experimental evaluations and comparisons with existing studies demonstrate the gripper's ability to successfully assist in both dressing and dressing of trousers in confined spaces with a high success rate. This research contributes to the advancement of assistive robotics, empowering elderly, and physically impaired individuals to maintain their independence and improve their quality of life.

Uncertainty-integrating, automated design of gripper jaws for robust grasping of electrical connectors

AbstractFor robust grasping of workpieces with complex surface geometries such as the plugs of electrical connectors (ECs), individually designed gripper jaws are commonly required. The manual design of the latter is time-consuming, iterative, expensive, and requires expert knowledge. Therefore, automating the design process offers the potential to increase efficiency and reduce costs. However, the plugs of ECs often involve interference contours which pose a high risk for a grasp to fail. Thus, this paper introduces an approach for the automated design of gripper jaws that considers complex surface geometries with interference contours. Thereby, expected geometric uncertainties in the relative pose between a plug and a gripper system can be parameterized by a user. The key steps of our approach are to automatically simulate collision volumes between the gripper jaws and the workpiece to map geometric uncertainties in software for computer-aided design (CAD) and to adapt the gripper jaws accordingly within minutes and without manual design. The results of the experimental validation using three different high-voltage plugs show that the presented approach is suitable for robust grasping of such workpieces. In summary, our work intends to contribute to a more efficient design process of gripper systems for workpieces with complex surface geometries such as plugs of ECs.

Inherently integrated microfiber-based flexible proprioceptive sensor for feedback-controlled soft actuators

For the accurate and continuous control of soft actuators in dynamic environments, the movements of the soft actuators must be monitored in real-time. To this end, various soft actuators capable of self-monitoring have been developed by separately integrating sensing devices into actuators. However, integrating such heterogeneous sensing components into soft actuators results in structural complexity, high manufacturing costs, and poor interfacial stability. Here, we report on intelligent pneumatic fiber-reinforced soft actuators with an inherent flexible proprioceptive sensor that uses only the essential components of typical fiber-reinforced soft actuators. The inherent flexible proprioceptive sensor is achieved by leveraging two parallel conductive microfibers around an elastomeric chamber of the soft actuator, which simultaneously acts as both a capacitive bending sensor and radial expansion limiting fibers of typical fiber-reinforced soft actuators. The proprioceptive soft actuator exhibits excellent mechanical actuation up to 240° bending motion and proprioceptive sensing performance with high sensitivity of 1.2 pF rad−1. Mathematical analysis and simulations of the soft actuator can effectively predict the bending actuation and capacitive responses against input pressures. We demonstrate that proprioceptive soft actuators can be used to construct a soft gripping system and prosthetic hand which express various hand gestures and perform dexterous manipulation with real-time proprioceptive sensing capability.

Development of a dry mock-up system for verifying pyroprocess automation

This paper presents the design and operation of an autonomous robot for pyroprocess automation, which requires unique approaches beyond those used in industrial applications to achieve the desired performance. Maintaining an extremely dry atmosphere is crucial to handle various materials, including chloride, and an autonomous system ensures this dry environment. The drying room dehumidifier was carefully selected and designed to generate dry air, and different types of dry air conditioning performance were evaluated, including assessing worker accessibility inside the mock-up to determine the system's feasibility. Containers used for process materials were modified to fit the gripper system of the gantry robot for automation. The loading and unloading of process materials in each equipment were automatically performed to connect the process equipment with the robotic system. The gantry robot primarily operated through macro motion to approach waypoints containing process materials, eliminating the need for precise approach motion. The robot's tapered jaw design allowed it to grasp the target object even with imperfect positioning. Robot motions were programmed using a robot simulator for initial positioning and motion planning, and real accuracy was tested in a mock-up facility using the OPC platform.

New classification of industrial robotic gripping systems for sustainable production

Robotics is an overarching trend in modern high-tech production, contributing significantly to automation. They are used in various industries to perform multiple tasks, and their number is constantly growing. Robots interact with the production object with the help of gripping systems, which are an essential component of industrial robots and manipulators designed for reliable grasping. Therefore, the process of design and rational selection of grippers for considering production conditions receives considerable attention worldwide. The article offers a comprehensive approach to the design of gripper systems as an integral element of the “gripping system – part – environment – production equipment” system to ensure further rational selection considering specific production conditions. A scientific approach to assessing the design of gripping systems was proposed to systematize knowledge in designing gripping systems. In the paper, the principal structural scheme of the robotic gripping system was developed, and the purpose of elements and design requirements were determined. Also, the sequence of stages in the process of selecting the elements of the gripping system has been proposed. The comprehensive system “gripping system – part – environment – production equipment” has been identified considering the mutual influence of structural elements. This work may be helpful to engineers and researchers while designing new gripping systems or selecting the most suitable one from the database. It can improve the rational selection of the element base and the structure of the gripping system by systematizing the experience in the gripper system design. Moreover, due to modern trends in automation and digitalization, the presented classification and coding system for gripping systems can be used in Computer Aided Process Planning and Computer Aided Gripping Systems Design systems. It can help to realize the approach “from the part geometry to the gripping systems design”. Also, it will ensure the production planning stage’s effectiveness due to reducing the time for robotic gripping systems’ design and increasing production safety, flexibility, autonomy, and performance.

A modular framework of robot gripping tools for human robot collaborative production lines

Robot gripping systems are subject to many technological transformations because of their need to adjust to a continuously changing market involving a large diversity of products and materials. This issue is further burdened by the high integration and control complexity in HRC environments. This paper proposes a modular framework of gripping tools with versatility in grasping and processing of different components based on automatic tool change solutions. Control and safety modules are being investigated for the flexible and safe handling of components. The proposed framework is being applied to two industrial scenarios from the white goods and the automotive sectors.

On intelligent object sorting and assembly: versatile end-effector for robotized handling of electrical components

In the ever-evolving landscape of industrial automation, versatile and ‘smart’ robotic solutions for sorting and assembly operations have become increasingly important. The diversity of product variants in terms of size, geometry, material and texture increases the complexity of the tooling needed for robot handling during assembly. To mitigate this challenge, this study presents a novel design of a versatile and cost-effective robot end-effector, to sort out products from a stack of multi-variant objects and assemble them with minimal re-grasping adjustments. The proposed smart adaptable gripper is equipped with multiple suction heads, each with independent triggering capabilities, enabling the end-effector to adapt to diverse parts’ geometry. A vision-based system has also been integrated to the gripping system enhancing it with perception capabilities. A two-step approach is employed to address the kitting to assembly problem from start to end utilising real-time pixel-wise grasp quality analysis in combination with gripper’s masks convolution for optimized grasping. The performance of the proposed framework in terms of the design functionality is evaluated in a case study involving the manipulation and assembly of electronics on a control panel derived from the elevators’ manufacturing industry.

Automated Configuration of Optimized Customer Specific Mechatronic Systems Using Behavior Models

The diversity of component manufacturers' product portfolios is often one of their greatest assets, as it allows them to offer appropriate solutions to a wide variety of customers. However, this diversity is also one of the greatest challenges, as it often makes it nearly impossible to design an optimal mechatronic system by manually selecting components. This is where the Digital Twin of the components can help. By providing behavior models and relevant information, existing optimization algorithms can be used to optimize for system-relevant key performance indicators enabling an automated system design process. The method presented in this paper is validated for a vacuum gripping systems.

Effect of the apron in the mechanical characterisation of hyperelastic materials by means of biaxial testing: A new method to improve accuracy

Biological soft tissues and polymers used in biomedical applications (e.g. in the cardiovascular area) are hyperelastic incompressible materials that commonly operate under multi-axial large deformation fields. Their characterisation requires biaxial tensile testing. Due to the typically small sample size, the gripping of the specimens commonly relies on rakes or sutures, where the specimen is punctured at the edges of the gauge area. This approach necessitates of an apron, excess of material around the gauge region.This work analyses the apron influence on the estimated mechanical response of biaxial tests performed by using a rakes gripping system, with the aim of verifying the test accuracy and propose improved solutions.In order to isolate the effect of the apron, avoiding the influence of anisotropy and inhomogeneity typical of most soft tissues, homogeneous and isotropic hyperplastic samples made from a uniform sheet of casted silicone were tested. The stress-strain response of specimens with different apron sizes/shapes was measured experimentally by means of biaxial testing and digital image correlation. Tests were replicated numerically, to interpret the experimental findings.The apron surrounding the gauge area acts as an additional annular constraint which stiffens the system, resulting in a significant overestimate in the stress values. This error can be avoided by introducing specific cuts in the apron.The study quantifies, for the first time, the correlation between the apron size/shape and the experimental stress overestimation, proposing a research protocol which, although identified on homogeneous hyperelastic materials, can be useful in providing more accurate characterisation of both, synthetic polymers and soft tissues.

Implementation analysis of vacuum area gripping system in pick and place machinery in wooden door company

Companies must grow in order to boost efficiency and production quality due to competition in the wood industry, particularly in the production of increasingly hard wooden doors. The issue that businesses face frequently is the occurrence of product flaws during the manufacture of wooden doors. A method for lifting, positioning, and moving door goods has been created by PT XYZ, one of the export-quality wooden door firms. By reducing product flaws, this study hopes to raise the quality of wooden doors. The pick and place machine's grasping system is the primary cause of the high prevalence of impairment. There are specific flaws in the door-gripping mechanism that increase the likelihood of product failures from falling and workplace accidents. After reworking the vacuum area gripping system, which uses suction technology, one of the Schmalz brands manufactured in Germany is outfitted with an external suction motor as a source of suction energy. The tool can lift loads up to 50 kg in accordance with specifications at a consistent speed, according to development results

AI Vision-based Smart Gripper System For Intelligent Manufacturing

AI Vision-based Smart Gripper System For Intelligent Manufacturing

Application of machine learning to object manipulation with bio-inspired microstructures

Bioinspired fibrillar adhesives have been proposed for novel gripping systems with enhanced scalability and resource efficiency. Here, we propose an in-situ optical monitoring system of the contact signatures, coupled with image processing and machine learning. Visual features were extracted from the contact signature images recorded at maximum compressive preload and after lifting a glass object. The algorithm was trained to cope with several degrees of misalignment and with unbalanced weight distributions by off-center gripping. The system allowed an assessment of the picking process for objects of various mass (200, 300, and 400 g). Several classifiers showed a high accuracy of about 90 % for successful prediction of attachment, depending on the mass of the object. The results promise improved reliability of handling objects, even in difficult situations.

Dynamic modeling and robust vibration control of a high-speed macro-micro gripping system

This paper presents dynamic modeling and robust vibration control for a high-speed macro–micro gripping system comprised of an air-floating macro-positioning stage and a compliant piezoelectric microgripper. A dynamic displacement coupling model is established considering rigid-flexible coupled macro-micromechanical structures, electromechanical properties containing the piezoelectric actuator and power amplifier, and hysteresis nonlinearity. Then, a comprehensive position/force model is proposed by integrating displacement, load, and force characteristics to describe the position and gripping force of micro-objects. Regarding system disturbances and model uncertainties, robust control strategies for pure displacement and position/force cooperation are devised utilizing perturbation H∞ controllers and Kalman filters. Experimental results indicate that measurement noises for pure displacement and position/force are effectively reduced. Position/force disturbances arising from sudden mutual changes are decreased from 14.39 μm and 7.25 mN to 0.82 μm and 0.85 mN. Also, position/force vibrations excited by high-speed macro motion are suppressed by 31.99 % and 58.06 %. Both precision tracking and vibration suppression are still well achieved, even at significant parameter perturbation. Thus, experiments verify the feasibility of the proposed control strategy.

Tomato Fruit Quality as Affected by Ergonomic Conditions While Manually Harvested

The harvest phase plays an important role in the whole process of production of tomato fruit. Therefore, it is necessary to ensure a technological process that will not damage biological materials. The harvest phase plays an important role in the whole process. Many growers use special machines for harvesting, but there are fruits and vegetables that should be harvested manually to avoid damaging the surface or parenchyma tissue of the harvested objects. In addition to maintaining the quality of biological materials, work comfort, and ergonomic conditions for pickers should be ensured because inadequate working conditions do not encourage employees to undertake manual work in horticulture. Therefore, there have been shortages of workers on Polish plantations in the past year. Based on manual tomato harvesting, the authors conducted a matched qualitative research study on biological materials and work ergonomics. For this purpose, the Grip System was used to investigate tomato quality by assessing the impact of picking hand pressure (in three different picker’s body positions) on the harvested objects. Simultaneously, for the picker’s ergonomic analysis, a non-invasive surface electromyography method was used to precisely measure changes in muscle motor unit action in the picker’s wrist and lumbar spine while in three characteristic picker’s positions. The tests found that the poorest body position was when the body was deeply inclined and simultaneously twisted. No significant effect was shown of the body position of the tomato picker on the deterioration of the picked fruit quality. However, body positions significantly affect the level of physical load and work comfort.

Hybrid-excited magneto-responsive soft actuators for grasping and manipulation of objects

Magneto-responsive soft actuators have attracted significant attention due to their non-contact nature and exceptional responsiveness. However, existing actuation methods relying on a single magnetic source, such as permanent magnets or electromagnets, suffer from an imbalance between flexible regulation and low energy operation. In this study, we propose a novel hybrid-excited magnetic actuation approach that leverages the synergy between permanent magnets and electromagnets. By utilizing the static magnetic field generated by permanent magnets to stabilize the deformation state of soft actuators, and employing the pulsed magnetic field generated by electromagnets to regulate the deformation, we achieve a harmonious combination of flexibility and energy efficiency. Furthermore, we introduce a two-step magnetization method that enhances the deformability of multi-arm soft actuators, enabling complete closure after deformation. To exemplify the practical implications, we develop a magnetic soft gripper system capable of versatile object manipulation, offering precise control over the grasping and releasing processes without the need for electrical energy consumption. Experimental results demonstrate the exceptional performance of the soft gripper, including a high lifting ratio (larger than 50), fast (<0.05s) and adjustable response. Moreover, we substantiate its potential in real-world scenarios through targeted delivery of single objects with different physical features and simultaneous manipulation of multiple objects with selective capability. This research presents a significant advancement in the field of magneto-responsive soft actuators, offering novel design principles, improved performance, and promising applications across various domains.

Tensile testing of Yttria-stabilized zirconia ceramic tapes for solid oxide cells

High temperature solid oxide cells (SOCs) play an important role in the worldwide green energy transition due to the high efficiency and great flexibility. For the cost and efficiency optimization of electrolyte-supported SOCs, a crucial property is the mechanical stability of the cell, which is mainly provided by the electrolyte. In this study, the authors investigate the tensile mechanical properties of 3% yittria-stabilized zirconia (3YSZ) ceramic electrolyte tapes, allowing the evaluation of a large material volume compared to the flexural test. A novel gripping system for misalignment minimization is developed. The sample machining is found to have an influence on the strength, as ground samples have an average strength above 1000 MPa, while the laser cut ones show strengths below 500 MPa. The influence of edge roughness and phase transformation during grinding is determined and the crack initiation point is examined.

Design and Implementation of a Compliant Gripper for Form Closure of Diverse Objects

This research presents a comprehensive study on the design and implementation of a flexible robotic gripper. Conventional grippers utilized in articulated robotic arms are often limited in their capabilities, being restricted to specific tasks or fixed object sizes. While soft grippers are a viable option, they have limitations in terms of grasping objects across a wide range and providing complete coverage. In this study, a novel compressible gripper is developed to enable safe and secure grasping of objects with varying sizes and shapes within a wide range. The gripper features a grasping area measuring 14 cm × 6 cm, allowing complete coverage of objects within this surface area. The current prototype with 7 cm of compressibility demonstrates the ability to grasp objects with a width difference of 7 cm with a maximum thickness of 15 cm, enabling manipulation of objects with varying widths, as defined by user-programmable parameters. The functionality of the gripper is based on the compressibility of the 3D-printed thermoplastic polyurethane (TPU) material. The flexible part of the gripper can be easily interchanged, offering versatility by accommodating different thicknesses without the need to replace the entire gripper mechanism. The gripper system operates using an open-loop control system, enhancing user-friendliness. Experimental evaluation of the gripper involved the creation and analysis of a CAD model followed by the fabrication of a prototype. The prototype exhibited exceptional performance in grasping objects of diverse sizes, shapes, and textures, demonstrating the effectiveness of the developed soft gripper system. The scalability of the soft gripper enables seamless integration with various types of articulated robotic arms, while the maximum weight limit for objects will be defined based on the robotic arms’ limitations. The research findings highlight the promising capabilities of the compressible gripper in enhancing the versatility and efficiency of robotic grasping systems, offering a significant contribution to the field of robotics.