Search

Small unmanned aerial vehicles (UAVs) have gained significant interest in the last decade. More specifically these vehicles have the capacity to impact package delivery logistics in a disruptive way. This paper reviews research problems and state‐of‐the‐art solutions that facilitate package delivery. Different aerial manipulators and grippers are listed along with control techniques to address stability issues. Landing on a platform is next discussed which encompasses static and dynamic platforms. Landing on a dynamic platform presents further challenges. This includes delayed control responses and poor precision of the relative motion between the platform and the aerial vehicle. Subsequently, risks such as weather conditions, state estimation, and collision avoidance to ensure safe transit is considered. Finally, delivery UAV routing is investigated which categorizes the topic into two areas: drone operations and drone–truck collaborative operations. Additionally, we compare the solutions against design, environmental, and legal constraints. [ABSTRACT FROM AUTHOR]

With the development of human-like robotic technologies, robots have been advanced to sense and recognize objects, which is one branch of artificial intelligence to mimic human reactions. Although high-performance computer technologies are used, the ability of object recognition by touch is still low due to the lack of proper sensors. Therefore, this research studied the object learning and recognition system through robot touches by developing an artificial sensory system acting as an electronic skin with tactile sensors. The Tactile Sensor is developed in this research, consisting of 15 Tactile Sensor Arrays and the palm’s touchpoints. Furthermore, recognition analysis was developed on Bag of Word (BoW) and Convolution Neural Network (CNN) algorithms. With the BoW technique, using Support Vector Machine (SVM) as a classifier with Moment Analysis Descriptor (MA) provided the highest accuracy, showing more than 80.15% accuracy from five grasping of an object. With the CNN approach, InceptionNetV3 provided the highest accuracy of 98.28% from only one capture of an object.

Parallel pinch is an important grasp method. The end phalanx of the traditional parallel pinch and self-adaptive gripper moves in an arc trajectory, which requires the auxiliary lifting motion of the industrial manipulator, which is inconvenient to use. To solve this problem, a novel robot finger is designed and implemented—Hoecken's finger. In this finger, the Hoecken linkage mechanism is used to realize the straight-line trajectory of the end joint, the differential mechanism set on the surface of the phalanxes is used to realize the shape self-adaptation of the first and second phalanxes, and the parallel four-bar linkage in series is used to realize the attitude keeping, thus comprehensively realizing the underactuated gripper driven by a single motor. After analyzing the grasp force and grasp motion of Hoecken's fingers, the optimized parameters are obtained, and the Hoecken's gripper is developed. The experimental results show that the gripper can realize the self-adaptive grasp function of straight parallel pinch, the grasp is stable, and the grasp range is large. It can be applied to more scenes that need to grasp objects. [ABSTRACT FROM AUTHOR]

The human hand is one of the most complex organs of the human body, capable of performing skilled tasks. Manipulation, especially grasping is a critical ability for robots. However, grasping objects by a robot hand is a challenging issue. Many researchers have used deep learning and computer vision methods to solve this problem. This paper presents a humanoid 5-degree-of-freedom robot hand. The robotic hand is made using a 3D printer and 5 servo motors are used to move the fingers. In order to simplify the robotic hand, a tendon -based transmission system was chosen that allows the robot's fingers to flexion and extension. The purpose of this article is to use deep learning algorithm to grasping different objects semi - automatically. In this regard, a convolutional neural network structure is trained with more than 600 images. These images were collected by a camera mounted on the robot's hand. Then, the performance of this algorithm is tested on different objects in similar conditions. Finally, the robot hand is able of successfully grasping with 85% accuracy. [ABSTRACT FROM AUTHOR]

The current underactuated robot hands use a single actuator to drive multiple degrees of freedom, enabling them to perform grasping functions. This paper design a multi-mode compound grasping robot finger driven by linkage, called MCG hand. The MCG hand includes a base, two motors, three phalanx, multiple shafts, two motors, two driving wheels, four linkages, three springs, and two limit blocks. This unique design allows the MCG finger to perform various grasping modes, such as parallel, coupling, middle, and distal phalanx self-adaptive, proximal, and distal gesture-changeable modes, as well as their combinations. The device can independently control the rotation of the proximal phalanx and the distal joint and realize the parallel pinching action of the distal phalanx. It can also realize the coupling function of the proximal and distal phalanx. It has automatic adaptability to objects of different shapes and sizes. Furthermore, the MCG finger provides enveloping grasping with multiple contact points, resulting in a more stable grip. The easy switching between modes through simple control, along with its wide application range and low manufacturing and maintenance costs, make the MCG hand a versatile solution for various applications. [ABSTRACT FROM AUTHOR]

Parallel pinching is an important grasping mode of robot hands. However，because the end phalange moves along the arc track，the robot hand needs the manipulator to cooperate with the lifting when pinching objects on the desktop，which increases the difficulty of grasping objects of different sizes. To solve this problem，a linear parallel pinching mode is introduced in which the end phalange is translational in a linear trajectory. Based on this model，a SHKL finger，for linear parallel pinching and adaptive grasping based on springs and Hoeckens linkage is proposed. The SHKL finger uses Hoeckens linkage to realize the linear movement of the end joint，uses double parallel four-bar linkage with the same direction and speed to realize the attitude fixation of the end phalange relative to the palm，and uses elastic joints，springs and limits to realize the self-adaptive grasping. The theoretical analysis and experimental results show that the SHKL hand has the functions of linear parallel pinching and self-adaptive grasping. Its grasping is stable and its control is easy.

Modern industrial applications of robotics such as small-series production and automated warehousing require versatile grippers, i.e., grippers that can pick up the widest possible variety of objects. These objects must often be grasped or placed inside a container, which limits the size of the gripper. In this article, we propose to combine the two most popular gripper technologies in order to maximise versatility: finger grippers and suction-cup (vacuum) grippers. Many researchers and a few companies have followed this same idea in the past, but their gripper designs are often overly complex or too bulky to pick up objects inside containers. Here, we develop a gripper where the suction cup is lodged inside the palm of a two-finger robotic hand. The suction cup is mounted on a retractile rod that can extend to pick up objects inside containers without interference from the two fingers. A single actuator drives both the finger and sliding-rod motions so as to minimise the gripper complexity. The opening and closing sequence of the gripper is achieved by using a planetary gear train as transmission between the actuator, the fingers and the suction cup sliding mechanism. Special attention is paid to minimise the overall gripper size; its diameter being kept to 75 mm, which is that of the end link of the common UR5 robot. A prototype of the gripper is built and its versatility is demonstrated in a short accompanying video.

In this paper, a novel self-adaptive underactuated robot hand with rigid-flexible coupling fingers (SAU-RFC hand) is proposed. The seven degrees of freedom (DOFs) SAU-RFC hand is driven by four servomotors, consists of three fingers, including two side-turning (ST) fingers and one non-side-turning finger. Specially, the ST fingers can perform synchronous reverse rotation laterally with each other. Each finger with three joints and two DOFs introduces a flexible structure, and the inner part of the proximal phalanx that makes most of the contact with the object is replaced by a flexible belt. The fingers can generate flexion/extension under the pull of the flexible belt, and the middle and distal phalanxes are mechanically coupled through a four-bar linkage. In particular, the flexible belt in the inner direction of the finger will deform, while it will not deform in the outer direction since the outer is a rigid structure. The flexible belt not only plays the role of transmitting power but also has the effect of uniformizing the contact force. Due to the rigid-flexible finger structure, the developed robot hand has a higher self-adaptive grasping ability for objects with different shapes, sizes, and hardness. In addition, the kinematic and kinetic analyses of SAU-RFC hand are performed. A contact force distribution model is established for the flexible belt, which demonstrates its effect of promoting uniform force distribution theoretically. In the end, experiments are conducted on different objects to verify the performance of SAU-RFC hand. [ABSTRACT FROM AUTHOR]

Product management using a multifunctional shelf, and manipulation using an electromagnet hand and a magnetic marker, are proposed for stock and disposal tasks. The multifunctional shelf manages the type, position, and number of products on the shelf, and plans display and disposal operations. The shelf provides directions to a mobile manipulator for moving products on the shelf according to the display and disposal plan. The proposed multifunctional shelf has a camera on each level that helps the mobile manipulator recognize the product. By optimizing the movement of products, the display and disposal work can be performed much more efficiently. To quickly grasp the product, a new manipulation strategy using a magnetic marker and an electromagnet hand is proposed. The electromagnet hand has two electromagnets and can quickly grasp and release the magnet marker by changing the S/N pole pair. Experiments using the proposed multifunctional shelf and electromagnet hand were conducted to demonstrate the effectiveness of the proposed system. [ABSTRACT FROM AUTHOR]

• The detail of each module of the new developed pumpkin harvesting robot was illustrated in the paper. • The fruits detection results of using YOLO v2 to YOLO v8 have done and the results are compared. • A one-shot 3D camera and robot calibration method was proposed. It is a hard job for farmers to harvest heavy fruits such as pumpkin fruits because of the aging problem of farmers. To solve this problem, this study aims to develop an automatic pick-and-place robot system that alleviates labor demands in pumpkin harvesting. We proposed a system capable of detecting pumpkins in the field and obtaining their three-dimensional (3D) coordinate values using artificial intelligence (AI) object detection methods and RGB-D camera, respectively. The harvesting system incorporates a crawler-type vehicle as the base platform, while a collaborative robot arm is employed to lift the pumpkin fruits. A newly designed robot hand, mounted at the end of the robot arm, is responsible for grasping the pumpkins. In this paper, we utilized various versions of YOLO (from version 2 to 8) for pumpkin fruit detection, and compare the results obtained from these different versions. The RGB-D camera, that was mounted at the root of the robot arm, captures the position of the pumpkin fruits in camera coordinates. We proposed a calibration method can simply transform the position to the coordinates of robot arm. In addition, we finished all the software and hardware of the pumpkin fruits pick-and-place robot system. Field experiments were conducted at an outdoor pumpkin field. The experiments demonstrate the fruits detection accuracy rate exceeding 99% and a picking success rate surpassing 90%. However, fruits that were surrounded by excessive vines could not be successfully grasped. [ABSTRACT FROM AUTHOR]

Featured Application: The ESMGM robot hand has a universal grasping function. With its continuous improvement, it could be widely used in industrial production, medical rehabilitation, and other services in the future. Giving robot hands more powerful functions has always been one of the goals pursued by scholars in this field. In this paper, an electromagnetic switching multiple grasping modes robot hand (ESMGM hand) is proposed, which integrates three typical grasping modes and therefore has versatile usage and improved performance. The switchable CPS mechanism developed in this paper integrated the parallel grasping and coupled grasping modes, which are incompatible with each other, through ingenious design. The partial effective transmission mechanism guarantees the fusion and connection to self-adaptive grasping mode from both parallel grasping mode and coupled grasping mode. Based on the above two essential mechanisms, the specific structure of the ESMGM robot hand is designed. Theoretical analyses for the kinematic and grasping forces are performed, and the results show that the ESMGM hand not only has multiple grasping functions but also has the characteristics of equitable grasping motions, adequate grasping forces, and stable grasping effects. To further verify the performance of the ESMGM hand, the prototype of the ESMGM hand is manufactured, and grasping experiments are performed. The grasping forces distribution results are consistent with the theoretical analysis results. The general grasping experiments also illustrate that the ESMGM hand has the features of fast electromagnetic switching speed, good adaptability, high stability, fast response, and broad application prospects. [ABSTRACT FROM AUTHOR]

Abstract Robotic grippers that gently handle objects of various shapes are required for various applications these days. Conventional finger-shaped grippers are multifunctional and can grip various objects; however, grasping an item without slippage requires planning the positioning of the fingers at appropriate locations on the item. Hence, a ring-shaped soft gripper that coils itself around objects like a rubber band is suggested in this paper. The proposed gripper comprises a soft tube containing laminated sponges interleaved with plastic sheets. Evacuation of the air within the sponges shrinks them and decreases the diameter of the ring, thereby allowing the gripper to firmly hold objects. The gripper is therefore flexible enough to coil around objects of various shapes without gaps. Furthermore, the rigidity of the compressed sponges inside the gripper prevents wobbling of the gripped objects. The air within the gripper can be used to adjust the gripping force. The minimum diameter of the gripper after evacuating the air within the sponges is approximately one-fourth of the original diameter. Thus, the proposed gripper is expected to be used in various applications as it automatically conforms to the different shapes while simply gripping objects gently and securely.

Parallel pinch is an important grasp method. The end phalanx of the traditional parallel pinch and self-adaptive gripper moves in an arc trajectory, which requires the auxiliary lifting motion of the industrial manipulator, which is inconvenient to use. To solve this problem, a novel robot finger is designed and implemented—Hoecken’s finger. In this finger, the Hoecken linkage mechanism is used to realize the straight-line trajectory of the end joint, the differential mechanism set on the surface of the phalanxes is used to realize the shape self-adaptation of the first and second phalanxes, and the parallel four-bar linkage in series is used to realize the attitude keeping, thus comprehensively realizing the underactuated gripper driven by a single motor. After analyzing the grasp force and grasp motion of Hoecken’s fingers, the optimized parameters are obtained, and the Hoecken’s gripper is developed. The experimental results show that the gripper can realize the self-adaptive grasp function of straight parallel pinch, the grasp is stable, and the grasp range is large. It can be applied to more scenes that need to grasp objects.

The current underactuated robot hands use a single actuator to drive multiple degrees of freedom, enabling them to perform grasping functions. This paper design a multi-mode compound grasping robot finger driven by linkage, called MCG hand. The MCG hand includes a base, two motors, three phalanx, multiple shafts, two motors, two driving wheels, four linkages, three springs, and two limit blocks. This unique design allows the MCG finger to perform various grasping modes, such as parallel, coupling, middle, and distal phalanx self-adaptive, proximal, and distal gesture-changeable modes, as well as their combinations. The device can independently control the rotation of the proximal phalanx and the distal joint and realize the parallel pinching action of the distal phalanx. It can also realize the coupling function of the proximal and distal phalanx. It has automatic adaptability to objects of different shapes and sizes. Furthermore, the MCG finger provides enveloping grasping with multiple contact points, resulting in a more stable grip. The easy switching between modes through simple control, along with its wide application range and low manufacturing and maintenance costs, make the MCG hand a versatile solution for various applications.

This article proposes a parallel gripper with a rack and pinion mechanism that is more versatile than the traditional parallel grippers with three actuators. The proposed gripper can switch between large and small fingers via lengthening and shortening actions, which improves its ability to pick up objects with various sizes and weights, as well as in narrow workspaces. This function also enables the gripper to perform three-face grasping, wherein three faces of a grasped object are securely in contact with the gripper, thereby improving the robustness of grasping. The gripper can also perform in-hand manipulations using a stand. We analyze the grasping force of the three-face grasp and show that it is more robust against external forces that generate the moment about the normal of the finger surface than the traditional two-face grasp. Finally, we demonstrate the improved abilities of the developed gripper and the robustness of the three-face grasp through the experimental results. The possible applications of this gripper include tasks in which the sizes, weights, and arrangements of the objects are not optimized for robot hands. [ABSTRACT FROM AUTHOR]

For complex tasks such as tying a knot, simply creating a robot hand with many degrees of freedom is insufficient. It is also important to extract the requirements of the task, design the hand based on these requirements, and implement functions to use the hand effectively. Thus, in this study, we have designed a robot hand with three fingers each having three degrees of freedom and developed basic functions to realize rope-knotting tasks. In experiments, the designed robot hand and functions were applied to performing various manipulations during rope-knotting tasks, and the redundancy provided by the structure could be utilized to generate motions. [ABSTRACT FROM AUTHOR]

In various experimental settings, electromyography (EMG) signals have been used to control robots. EMG-based robot control requires intrinsic parameters for control, which makes it difficult for users to understand the input protocol. When a proper input is not provided, the response time of the system varies; as such, the user's subjective delay should be investigated regardless of the actual delay. In this study, we investigated the influence of the subjective perception of delay on brain activation. Brain recordings were taken while subjects used EMG signals to control a robot hand, which requires a basic processing delay. We used muscle synergy for the grip command of the robot hand. After controlling the robot by grasping their hand, one of four additional delay durations (0 ms, 50 ms, 125 ms, and 250 ms) was applied in every trial, and subjects were instructed to answer whether the delay was natural, additional, or whether they were not sure. We compared brain activity based on responses ("sure" and "not sure"). Our results revealed a significant power difference in the theta band of the parietal lobe, and this time range included the interval in which the subjects could not feel the delay. Our study provides important insights that should be considered when constructing an adaptive system and evaluating its usability. [ABSTRACT FROM AUTHOR]

In this study, we examine robotic proximity perception for both reactive control and 3D point-cloud acquisition using a multi-fingered robot hand. A reactive controller adjusts the relative position and orientation between the fingertips and the target object, while the robot-hand system gathers point-cloud data related to the shape of the object. An experimental result showed that the accuracy of the point-cloud generated using proximity perception was equivalent to or better than that of the point-cloud generated using a vision sensor. Based on the results, we propose proximity-based point-cloud acquisition using 'non-contact perception' motion to search the object's surface while preventing unintended collisions. The motion is then combined with the approaching and twisting motions of the robot hand. This enables multi-angles object detection complementarily with reactive fingertip control. Our experiments reveal that the proposed method can generate data-rich point-clouds for various general objects. [ABSTRACT FROM AUTHOR]

In contrast to their more rigid counterparts, soft robots have the ability to gently grip and maneuver objects with open-loop kinematic control. Guided by several recent designs and implementations of soft robot hands, the present paper analyzes a rod-based model for the fingers in the hand of a soft robot. We show precisely how gripping is achieved and how the performance can be affected by varying the system's parameters. The designs we are interested in feature pneumatic control of the soft robot and we model this actuation as a varying intrinsic curvature profile of the rod. Our work provides a framework for the theoretical analysis of the soft robot and the resulting analysis can also be used to develop some design guidelines.

Automation is currently delayed in garment factory. In order to automate the work in a garment factory, a method of single sheet separation from piled fabric is required. In this study, we developed a method of single sheet separation from piled fabrics by a roller hand mechanism with a rotating mechanism added to the tip of a robot hand. We designed a rigid body dynamics model for separating a sheet of fabric by this mechanism, and conducted experiments on the separation of a sheet of fabric. As a result, we succeeded in separating only single sheet of fabrics with a high probability. It is necessary to eliminate failures for practical use. However, it is difficult to eliminate failure completely due to the characteristics of fabrics. First, in order to improve the reliability of the separation process, we devised a method to determine the success of separation by the thickness of fabrics, created a mechanism and actually verified. We have succeeded in improving the reliability of single sheet separation process from piled fabrics. However, there was a failure pattern that cannot be addressed by this method. Therefore, we devised a method to determine the success of separation by the weight of fabrics, created a mechanism and actually verified. As a result, the reliability was further improved.

This study investigates object picking focusing on object arrangement patterns. Objects stored in distribution warehouses or stores are arranged in regular patterns, and the grasping strategy for object picking is selected according to the object arrangement pattern. However, object arrangement patterns have not been modeled for object picking. In this study, we represent objects as polyhedral primitives, such as cuboids or hexagonal cylinders, and model object arrangements by considering occlusion patterns for object model surfaces and considering whether the adjacent object occluding the surface is moveable. We define grasp patterns based on combinations of the grasp surfaces and discuss the grasping strategy when the grasp surfaces are occluded by adjacent objects. We then introduce newly developed gripper for picking arranged objects. The gripper comprises a suction gripper and a two-fingered gripper. The suction gripper has a telescopic arm and a swing suction cup. The two-fingered gripper mechanism combines a Scott Russell linkage and a parallel link. This mechanism is advantageous for the gripper in reaching narrow spaces and inserting fingers between objects. We demonstrate the picking up of arranged objects using the grippers. [ABSTRACT FROM AUTHOR]

Research on robots that can be used for communication with humans has become popular in recent years. Communication robots should ideally be as small as an infant in order to reduce the user's feeling of threat. In addition, non-verbal communication (such as gestures) is also important in facilitating smooth interactions between humans and robots. There are currently a few communication robots that are small sized and can generate hand gestures. In this paper, we propose a small robot hand, which is optimized for gesture communication by using a shape memory alloy (SMA). The SMA employed is a Ti–Ni alloy, which is used as an actuator. The SMA shrinks when it transforms into the austenite phase at temperatures higher than the transformation temperature. When it is in the martensitic phase at a lower temperature, it is expanded by an external force. Each finger of the robot hand is driven by an individual SMA wire. The specifications of the small robot including the hand size, operation angles in each finger joint, response times and power consumption were determined according to the human finger and existing small communication robots. These required specifications have been fulfilled by carefully designing the geometry and heating/cooling power control. A questionnaire-based survey was also conducted with a robot hand. The five-finger hand was successfully shown to generate recognizable symbolic gestures. [ABSTRACT FROM AUTHOR]

Traditional robot fingers with parallel and self-adaptive hybrid grasping mode have double-chain transmission mechanisms， which have disadvantages of complexity in mechanisms. A novel design of a parallel and indirectly self-adaptive underactuated robot finger with a single chain transmission mechanism， called PISA hand is presented. The method uses three gears， two racks， a slider， a block， a limit and a spring to achieve using a single motor to drive two phalanges. The PISA finger can realized the pinching grasp with the distal phalanx and enveloping grasp with the proximal phalanx with a slider and the distal phalanx. The composition and movement process of the PISA finger are introduced in detail. Theoretical analysis of the range and grasping force are given. Simulation and experimental results show that the PISA finger can automatically switch the grasping modes according to the different positions and shapes of the object so as to achieve stable grasping. The PISA hand has high transmission efficiency， compact structure.

Giving robot hands more powerful functions has always been one of the goals pursued by scholars in this field. In this paper, an electromagnetic switching multiple grasping modes robot hand (ESMGM hand) is proposed, which integrates three typical grasping modes and therefore has versatile usage and improved performance. The switchable CPS mechanism developed in this paper integrated the parallel grasping and coupled grasping modes, which are incompatible with each other, through ingenious design. The partial effective transmission mechanism guarantees the fusion and connection to self-adaptive grasping mode from both parallel grasping mode and coupled grasping mode. Based on the above two essential mechanisms, the specific structure of the ESMGM robot hand is designed. Theoretical analyses for the kinematic and grasping forces are performed, and the results show that the ESMGM hand not only has multiple grasping functions but also has the characteristics of equitable grasping motions, adequate grasping forces, and stable grasping effects. To further verify the performance of the ESMGM hand, the prototype of the ESMGM hand is manufactured, and grasping experiments are performed. The grasping forces distribution results are consistent with the theoretical analysis results. The general grasping experiments also illustrate that the ESMGM hand has the features of fast electromagnetic switching speed, good adaptability, high stability, fast response, and broad application prospects.

There has been an explosion of ideas in soft robotics over the past decade, resulting in unprecedented opportunities for end effector design. Soft robot hands offer benefits of low-cost, compliance, and customized design, with the promise of dexterity and robustness. The space of opportunities is vast and exciting. However, new tools are needed to understand the capabilities of such manipulators and to facilitate manipulation planning with soft manipulators that exhibit free-form deformations. To address this challenge, we introduce a sampling based approach to discover and model continuous families of manipulations for soft robot hands. We give an overview of the soft foam robots in production in our lab and describe novel algorithms developed to characterize manipulation families for such robots. Our approach consists of sampling a space of manipulation actions, constructing Gaussian Mixture Model representations covering successful regions, and refining the results to create continuous successful regions representing the manipulation family. The space of manipulation actions is very high dimensional; we consider models with and without dimensionality reduction and provide a rigorous approach to compare models across different dimensions by comparing coverage of an unbiased test dataset in the full dimensional parameter space. Results show that some dimensionality reduction is typically useful in populating the models, but without our technique, the amount of dimensionality reduction to use is difficult to predict ahead of time and can depend on the hand and task. The models we produce can be used to plan and carry out successful, robust manipulation actions and to compare competing robot hand designs.

We have developed a pneumatic artificial rubber muscle having a bending direction that can be changed using two shape-memory polymer (SMP) sheets, the stiffness of which depends on the temperature. In the present study, we attached two SMP sheets with embedded electrical heating wires to both sides of a pneumatic artificial rubber muscle in order to realize multidirectional actuation and evaluated the basic characteristics of the artificial muscle. The actuator is based on the design of a conventional curved-type artificial rubber muscle. Since only a heated SMP sheet becomes soft, the rigid SMP sheet inhibits the extension of the side of the actuator. Therefore, bending motion can be induced when air is supplied to the internal bladder. By controlling the temperature of the SMP sheets, the bending direction of the prototype actuator could be changed. Namely, three kinds of motions, such as two-directional bending and axial extension, became possible. Moreover, we improved the manufacturing method and the structure of the artificial muscle, such as the stitching method and the SMP sheet thickness, and evaluated the characteristics of the two-directional bending and the axial extension motions of the prototype actuator. We also calculated the theoretical values and compared these values with the experimental results. Furthermore, we examined the application of the actuators to a robot hand. Using the two-directional motion of the actuator, the proposed robot hand can grasp either small or large objects. The experimental results conducted using this prototype confirm the feasibility of the newly proposed actuator. [ABSTRACT FROM AUTHOR]

Numerous studies have been conducted on three-finger robot hands, which are widely used in industries. These studies led to the development of motorized prosthetic hands for amputees. Although many developers have focused on the functionality of motorized prosthetic hands, prosthetic users place more importance on the human-like motion of the device owing to social implications. Therefore, this study aims to achieve human-like flexion of a three-finger robot hand. Each finger contains three phalanges joined by pivots and torsional return springs. A tendon wire runs through guide pins inside the phalanges up to the linear actuator located in the forearm. When the tendon wire is pulled, the finger is flexed. The return springs are optimally selected based on ADAMS simulations and kinesiology of the human hand. The selection is then verified by experiments [ABSTRACT FROM AUTHOR]

Robotic grippers that gently handle objects of various shapes are required for various applications these days. Conventional finger-shaped grippers are multifunctional and can grip various objects; however, grasping an item without slippage requires planning the positioning of the fingers at appropriate locations on the item. Hence, a ring-shaped soft gripper that coils itself around objects like a rubber band is suggested in this paper. The proposed gripper comprises a soft tube containing laminated sponges interleaved with plastic sheets. Evacuation of the air within the sponges shrinks them and decreases the diameter of the ring, thereby allowing the gripper to firmly hold objects. The gripper is therefore flexible enough to coil around objects of various shapes without gaps. Furthermore, the rigidity of the compressed sponges inside the gripper prevents wobbling of the gripped objects. The air within the gripper can be used to adjust the gripping force. The minimum diameter of the gripper after evacuating the air within the sponges is approximately one-fourth of the original diameter. Thus, the proposed gripper is expected to be used in various applications as it automatically conforms to the different shapes while simply gripping objects gently and securely. [ABSTRACT FROM AUTHOR]

Teleoperation in soft robotics can endow soft robots with the ability to perform complex tasks through human-robot interaction. In this study, we propose a teleoperated anthropomorphic soft robot hand with variable degrees of freedom (DOFs) and a metamorphic palm. The soft robot hand consists of four pneumatic-actuated fingers, which can be heated to tune stiffness. A metamorphic mechanism was actuated to morph the hand palm by servo motors. The human fingers' DOF, gesture, and muscle stiffness were collected and mapped to the soft robotic hand through the sensory feedback from surface electromyography devices on the jib. The results show that the proposed soft robot hand can generate a variety of anthropomorphic configurations and can be remotely controlled to perform complex tasks such as primitively operating the cell phone and placing the building blocks. We also show that the soft hand can grasp a target through the slit by varying the DOFs and stiffness in a trail.

The traditional coupled and self-adaptive fingers realize firstly coupling and secondly self-adaptive hybrid grasping mode with three springs and two sets of independently transmission mechanisms,which have disadvantages of complexity in mechanisms,huge consuming in power,and difficulty in spring selection.Aiming at the problem,a novel coupled and self-adaptive underactuated finger mechanism,called COSA-LET finger is designed. The COSA-LET finer includes multiple racks,two toggle blocks,two limiting blocks,and two springs,which has two joints driven by one motor and a serial transmission mechanism. The coupling function of COSA-LET finger is realized by two opposite-direction racks,and a gear with a spring and a limiting block,the de-coupling problem of the finger in the self-adaptive stage is solved by dividing torque of the motor into two joint shafts with a spring and the delay-ticking transmission effect of two toggle blocks in linear empty-trip racks. Grasping force analysis and experimental results show that the COSA-LET robotic hand with three COSA-LET fingers has the coupled and self-adaptive hybrid grasping function,enable to adapt objects of different shapes and sizes,autonomously switch between the coupled mode and the self-adaptive mode.