Design Of Gripper Research Articles

An experimental study into displacement of a shape memory alloy actuated robotic microgripper

A parallelogram flexible hinge microgripper design made from aluminium alloy 7075-T6 material has been designed and manufactured with purpose of being able to manipulate a 25 μm diameter platinum wire. The structure is unique in that it is actuated using a shape memory alloy. The actuator circuit is designed so that during operation one microgripper arm remains ridged during the gripping process to ensure a consistent reference point whilst the other gripper arm flexes. The focus of the study is on the shape memory alloys capability in terms of providing the correct jaw displacement and displacement time in relation to the circuit input current. The results show a repeatable relationship between displacement and the applied current. In addition, it was shown that the current across the SMA wire increases it dramatically impacts the time taken for the jaws to close. The displacement time is also due to the resistive mechanical force of the microgripper body during operation. Overall the shape memory alloy actuator and optimised gripper design are shown to be useful for a number of industrial applications.

Design and development of a non-contact robotic gripper for tissue manipulation in minimally invasive surgery.

This paper describes the design and testing of a gripper developed for handling of delicate and flexible tissues during minimally invasive surgery. The device operates on the Bernoulli principle for generating hight-speed flow between the gripper and product surface threby creating vacuum which lifted the product. The Bernoulli gripper, which is widely employed in automated production lines, is a pneumatic manipulator capable of non contact gripping. This study experimentally investigates the applicable of Bernoulli gripper in minimally invasive surgery. The gripper allow tissues to be lifted with minimal contact thereby reducing the possibility of damaging the object. Most of the roobot grippers are not easily applicable in minimal invasive surgery due to the tissues are often delicate, easily damaged, adhesive and slippery. Due to surgeons can not gauging the force exerted on the grasped tissue during laparoscopic grasping, excessive grasp forces may lead to tissue damage. Although Minimally invasive surgery has many benefit, force feedback or touch sensation is limited during th operation in the currently available tools, creating the potential for excessive force application and unintended tissue injury. To overcome such problems, this paper proposes a concept to enable the use of non-contact grippers instead of traditional grippers. In this paper, an innovative approach of a gripper for grasping variable in sizes, shape and weight of chicken tissues are presented. The experimental results show that the Bernoulli principle gripper can be used to lift tissues of different texture and shape without damage. The main objective of this study is to highlights the importance of a non-contact end effector in Minimally invasive surgery and develop a gripper to grasp different tissues. A novel gripper such as the tested prototype has the potential to be used as grasper instrument in minimally invasive surgery. The results will be valuable for literature and future works. (www.actabiomedica.it)

Modelling and Simulation of Bending Behaviour of Thermoplastic Polyurethane based Soft Gripper

Smart polymers are used for designing of soft actuators for soft robotics applications. Performances of actuators depend upon mostly on stimulation environment, design for gripping with required bending moment and bending deflection. Dielectric polymers are one of the important smart polymers that is used grippers for soft robotics. It is actuated under high voltage in the range of kV but consumes less power. In this paper, thermoplastic polyurethane (TPU) is considered for design of gripper. A gripper design using TPU and rubber has been proposed and bending features were analyzed. It was found that thinner layer of TPU with thick layer of rubber is suitable for gripper design.

Characteristics of contactless swirl vane gripper by investigating the negative pressure and clearance

In this paper the characteristics of contactless swirl vane gripper and effect of negative pressure is discussed. The ultimate work of contactless gripper is to lift the light weight components without making contact by means of negative pressure created by the vanes. The vane’s model is modified and comparison of performance measurements is made for changed design and existing design. The contactless gripper is employed in various industries and handling of textile raw materials in specific wherever the high surface finishing is required. The vane gripper is modern tech tools applied in re-locating of components by creating gap between the gripper and component which produce negative pressure which is used for uplift of component. The uplift force is built by maintaining break between the vanes and the work-piece. The lifting force may be vary in accordance with the weight of the components, rpm of the motor used to rotate the vanes, distance available with the components and the vanes etc., The new gripper design is discussed in the following chapters and characteristics of the vanes are compared with parameters like lifting height, negative pressure value, clearance between the object and the vane.

A Reconfigurable Design for Omni-adaptive Grasp Learning

The engineering design of robotic grippers presents an ample design space for optimization towards robust grasping. In this paper, we adopt the reconfigurable design of the robotic gripper using a novel soft finger structure with omni-directional adaptation, which generates a large number of possible gripper configurations by rearranging these fingers. Such reconfigurable design with these omni-adaptive fingers enables us to systematically investigate the optimal arrangement of the fingers towards robust grasping. Furthermore, we adopt a learning-based method as the baseline to benchmark the effectiveness of each design configuration. As a result, we found that a 3-finger and 4-finger radial configuration is the most effective one achieving an average 96\% grasp success rate on seen and novel objects selected from the YCB dataset. We also discussed the influence of the frictional surface on the finger to improve the grasp robustness.

A novel design of shape-memory alloy-based soft robotic gripper with variable stiffness

Soft robotic grippers with compliance have great superiority in grabbing objects with irregular shape or fragility compared with traditional rigid grippers. The main limitations of such systems are small grasping force resulted from properties of soft actuators and lacking variable stiffness of soft robotic grippers, which prevent them from a larger wide range of applications. This article proposes a shape-memory alloy (SMA)-based soft gripper with variable stiffness composed of three robotic fingers for grasping compliantly at low stiffness and holding robustly at high stiffness. Each robotic finger mainly consisted of stiff parts and two variable stiffness joints is installed on the base with a specific angle. The paraffin as a variable stiffness material in the joint can be heated or cooled to change the stiffness of the robotic fingers. Results of experiments have shown that a single robotic finger can approximately achieve 18-fold stiffness enhancement. Each finger with two joints can actively achieve multiple postures by both changing the corresponding stiffness of joints and actuating the SMA wire. Based on these principles, the gripper can be applied to grasp objects with different shapes and a large range of weights, and the maximum grasping force of the gripper is increased to about 10 times using the variable stiffness joints. The final experiment is conducted to validate variable stiffness of the proposed soft grippers grasping an object.

Grasp and Micromanipulation with Human Hand – a New Experimentation and Systematization

This paper presents first the structural and functional characteristics of the human hand, a necessary stage even if these data exist in other papers too. Next, we experiment grasp of a rod-type object using one to five fingers, identifying nine possible situations, each case being exemplified by a corresponding picture. Below are the situations of grasping a small part with one and two fingers, in which case there are only two possible situations. Then there is the experimentation of grasping an object of any shape using from one to five fingers, in which case there are seven possible situations. We then experiment micromanipulation of a rod-type part. We also shows the adaptation of Cutkosky’s taxonomy through experiments for all the situations considered, plus the situation of grasping between two adjacent fingers and grasping with two opposing fingers of an object of relatively large size. Similarly, Lyons’ force grasp is being explored. The paper highlights the approach of specific aspects of grasping and micromanipulation for which suggestive tests are performed, and the unitary presentation of multiple cases of grasping using human hand for substantiation and extension of taxonomy, the best known until now, namely Cutkosky’s taxonomy. The paper is useful for improving the constructive and functional design of anthropomorphic grippers for robots.

Design Approach for Heavy-Duty Soft-Robotic-Gripper

Abstract Increased product customization based on customer requirements results in a large number of variants and thus smaller batch sizes in production. In order to maintain a flexible and dynamic interlinkage within a production system in terms of industry 4.0, it is necessary to implement flexible and adaptive handling and gripping solutions into the production process. A suitable way of integrating more flexibility into production is the use of compliant soft-robotic gripping systems, which are characterized by a high adaptability in terms of workpieces’ shape, size and structure compared to state-of-the-art grippers. Current focus in research refers on design and simulation of the repeatability of soft-robotic grippers with low payload capability, such as silicone-based Soft-Pneumatic-Actuators (SPA). Design and process parameters of soft-robotic grippers with higher payload capability, such as Fin Ray®, are usually revealed through time-consuming empirical test series. This paper demonstrates the potential of a new simulation-based approach in designing soft-robotic grippers for heavy-duty applications to reveal crucial design and process parameters with low effort and without empirical test series.

Программная система AgroGripModeling и алгоритмы оптимизации конфигурации робототехнического захвата

The paper discusses the scientific problem of optimization and control of robotic grippers, describes the algorithmic model and the AgroGripModeling software system for the design of agricultural grippers.

Algorithmic model for choosing configuration parameters for robotic gripping of agricultural products

The solution to the problem of automating the process of collecting agricultural products based on models, algorithms and multicriteria synthesis of the configuration of robotic capture and control of its software and hardware components during physical manipulations with objects of agricultural products is discussed. Performing monotonous physically difficult operations in agricultural production leads to the risk of disorders of the musculoskeletal system of workers, therefore, the use of robotic means for physical contact and manipulation with objects in agricultural production is an urgent task that ensures a reduction in the cost of production, an increase in the quality of operations performed and the labor safety of involved specialists. The variability of the physical and geometric characteristics of the fruits and the methods of their collection does not allow the creation of universal robotic grippers, therefore, active research is currently underway on the design of robotic grippers for manipulating the fruits of individual crops, differing in weight, density, geometry, surface roughness and other parameters. The article describes the developed conceptual model of robotic gripper control, including the description of the manipulator, gripper, sensor system and the manipulated object of agricultural products with various forms, physical and mechanical properties. The article analyzes the physical and mechanical properties of some vegetables and fruits, methods of cutting off the fruit, which should be taken into account when developing robotic grippers. There were discussed a four-stage technique for determining the parameters of robotic gripping, including determining the characteristics of the manipulated object; characteristics of the working environment; determination of the features of the manipulator on which the gripper is planned to be installed, and evaluation of the efficiency of the projected gripper according to a number of criteria. The developed algorithmic model of the choice of configuration parameters for robotic gripping of agricultural products is presented. It provides, based on the analysis of the properties of the manipulated object, the development of requirements for the configuration and gripping control system.

Study on design of gripper for cutting works focusing on surface geometry and friction characteristics

Study on design of gripper for cutting works focusing on surface geometry and friction characteristics

Designing Grippers Based on Model Decomposition and Primitive Fitting

In this work, we propose a structured approach of selecting and designing a set of grippers for an assembly task. Compared to experience-based gripper design method, our approach speeds up the design process by automatically generating a set of initial design options on gripper type and parameters according to the CAD models of assembly components. We use mesh segmentation techniques to segment the assembly components and fit the segmented parts with shape primitives, according to the predefined correspondence between primitive shape and gripper type, suitable gripper types and parameters can be selected and extracted from the fitted shape primitives.

Design of compliant gripper for surgical applications

ABSTRACT This article presents a novel design of monolithic compliant grippers for surgical applications. Compliant mechanisms are jointless mechanism and overcome the major traditional issues such as wear, friction and assembly error. Performance of compliant mechanism depends on the elastic body deformation to transmit motion between the linkages. In this article, the proposed gripper is designed with three different parts with different intended functions: tilting actuator, linear actuator and gripping jaws. Gripping jaws are developed to cut through shearing and collect tissues. A linear actuator transmits the input force to the gripping jaws. A tilting actuator tilts the whole gripper up and down to increase the shear force to cut the tissues. A conceptual mechanism is developed using topology optimisation for these concepts independently. Later, these parts are assembled and developed as a final solid model using SolidWorks. The structural performance of the gripper is investigated thoroughly using finite-element method.

Design and Implementation of a Multi-Function Gripper for Grasping General Objects

The development of a reliable pick-and-place system for industrial robotics is facing an urgent demand because many manual-labor works, such as piece-picking in warehouses and fulfillment centers tend toward automation. This paper presents an integrated gripper that combines a linkage-driven underactuated gripper with a suction gripping system for picking up a variety of objects in different working environments. The underactuated gripper consists of two fingers, and each finger has three degrees of freedom that are obtained by stacking one five-bar mechanism over one double parallelogram. Furthermore, each finger is actuated by two motors, both of which can be installed at the base owing to the special architecture of the proposed robotic finger. A suction cup is used to grasp objects in narrow spaces and cluttered environments. The combination of the suction and traditional linkage-driven grippers allows stable and reliable grasping under different working environments. Finally, practical experiments using a wide range of objects and under different grasping scenarios are performed to demonstrate the grasping capability of the integrated gripper.

Design of grippers for laparoscopic surgery and optimization of experimental parameters for maximum tissue weight holding capacity

Design of grippers for laparoscopic surgery and optimization of experimental parameters for maximum tissue weight holding capacity

Development of Two-Fingered Underactuated Robot Gripper using 3D Printer

This research present the development of a two-fingered underactuated robot gripper by using 3D printed machine with a material of Polylactic acid or PLA. The gripper design consist of two individual servo motors that drives the finger movement to perform a certain amount of grasping force. The new design of the finger using Solidworks was inspired by several existing robot gripper however with a low cost approach to obtain a good finger tracking and angular control. The fully fabricated and assembled gripper was then tested to determine the operation results during basic grasping and ungrasping by connected to Arduino Mega and MATLAB software. The angular data during the operation shows that the gripper successfully perform a stable operations despite some minor disturbance due to the mechanical defect on the servo plate. Further analysis will be conducted in the future in order to identify the full capability of the gripper in real world application such as force control operations.

Gripper Design for Automatic Trimming System in Forging Process

Labor shortage is one of the most common yet critical problems in industrial sectors. Using robotics and automation to replace human labor is one of the most effective solutions. In this research, robotic technology is implemented in the trimming process which is one of the key steps in faucet manufacturing. The system is designed to be able to deal with uncertainties of the shape of flash that are occurred due to the impression-die forging process. A gripper with specific jaws is designed to suit the workpiece. A vision system is used to identify the position and orientation of the workpieces. As a result, with the gripper and the vision system, the workpieces can be grasped, transferred, and loaded into the trimming machine at high success rate in comparison to human labor. In this paper, the design procedure of the gripper and performance of the gripper are emphasized.

Design and compliant estimate of robot gripper with light-emitting diode and photodiode positioning

Generally, robot gripper is the tool to enhancing the efficiency and ability of grasping task of robot manipulator. The interaction between the object and the grasping finger is the main target of robotic gripper design stage. For this research, robot gripper is then proposed as the new method of robot gripper force control using real-time estimate force feedback signal in order to achieve higher performance of grasping objects. Robot gripper kinematics is also analyzed and adjusted to more practical development. The object manipulation is also identifiable using recursive least square estimation technique of both hard and soft objects during grasping. Force controller of robot gripper is obtained using real-time estimate force feedback signal by the recursive least square method. Comparison of proportional–integral–derivative controller gains is tuned with different force feedback signals, normal force feedback, and estimate force feedback during grasping hard and soft objects validated by experiment. The results of design and development are illustrated by simulation and experimental methods. In addition, due to the limitation of electromagnetic interference, signals will not affect other instrumentations with restricted working condition. The range of gripper motion is detected by applied visible light signal of light-emitting diode and photodiode as limit sensors.

A Robot Gripper With Variable Stiffness Actuation for Enhancing Collision Safety

This article presents the design of a two-finger variable stiffness gripper and demonstrates how the adjustable compliance of the fingers can enhance manipulation safety and robustness during collisions. The compliance between actuators and fingers are generated by using repulsive magnets as preloaded nonlinear springs such that by adjusting the air-gaps between the magnets, the position and stiffness of the fingers can be controlled simultaneously. The capability of the proposed design in collision detection and reaction is demonstrated via two collision scenarios. In the first experiment, a momentum-based collision detection algorithm in the context of compliant grasping is investigated. In the second experiment, an optimal reaction strategy is developed that exploits the adjustable stiffness characteristics of the gripper to improve safety during collisions. The experimental results of the two scenarios indicate the effectiveness of the proposed gripper in enhancing collision safety.

An improved multi-objective antlion optimization algorithm for the optimal design of the robotic gripper

ABSTRACTThis paper presents an evolutionary method to find the optimally designed gripper configuration for the automated material handling process. The optimal design of the robot gripper is a non-linear, multicriteria and multi-constraint problem. Evolutionary computational methods are introduced to overcome the difficulty associated while finding the optimal dimensions of the gripper. In this study, an Improved Multi-objective Antlion Optimisation Algorithm (I-MOALO) has been proposed to find the optimal dimensions of three different robotic gripper mechanisms. The multi-objective optimisation problem (MOOP) is formulated from a geometric model of the gripper configuration with conflicting objectives. The primary objective is to find optimum force at the tip of the gripper while grasping the object while satisfying the constraint using the improved multi-objective antlion optimisation algorithm. A comparative analysis has been conducted to evaluate the effectiveness and performance of the proposed algorithm with well-established multi-objective algorithms. The performance analysis for comparing multi-objective algorithm has been carried out using some of the well-recognised performance metrics such as hypervolume, diversity metric, optimiser overhead, and the ratio of non-dominated individuals. From the result obtained after the performance metric study, it is concluded that the multi-criteria design optimisation problem of robotic gripper effectively solved using the proposed I-MOALO algorithm.