Applied Sciences

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15 pages, 4625 KiB

Open AccessArticle

Direction-Based Hybrid Strategy Combining Pushing and Hitting for Fast Object Singulation

by Muhammad Umair Ahmad Khan, Sanghwa Kim, Ji Yeong Lee and Byung-Ju Yi

Appl. Sci. 2021, 11(16), 7327; https://0-doi-org.brum.beds.ac.uk/10.3390/app11167327 - 09 Aug 2021

Viewed by 1358

This paper presents a hybrid singulation strategy for fast object singulation in a cluttered environment. Recent techniques related to object singulation in clutter have employed various kinds of pushing techniques and in some cases have also used hitting techniques. However, these techniques have [...] Read more.

This paper presents a hybrid singulation strategy for fast object singulation in a cluttered environment. Recent techniques related to object singulation in clutter have employed various kinds of pushing techniques and in some cases have also used hitting techniques. However, these techniques have not addressed the issue related to the direction of pushing and hitting which is vital for fast object singulation. Finding the appropriate direction of hitting and pushing helps in singulating objects quickly in a cluttered environment. This paper proposes the desired direction for pushing and hitting, combined with a hybrid strategy, that results in fast object singulation in a cluttered environment. The number of times of pushing and hitting in terms of time is chosen as the measure of performance. We employ multiple circular disks as the test example and carry out diverse experiments to corroborate the usefulness of the proposed object singulation algorithm. This approach is able to singulate objects quickly in complex formations. In this paper, we have combined both pushing and hitting and also proposed the direction of hitting and pushing in order to singulate objects in clutter quickly. Full article

(This article belongs to the Special Issue Object Recognition, Robotic Grasping and Manipulation)

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21 pages, 5911 KiB

Open AccessArticle

High-Speed Autonomous Robotic Assembly Using In-Hand Manipulation and Re-Grasping

by Taewoong Kang, Jae-Bong Yi, Dongwoon Song and Seung-Joon Yi

Appl. Sci. 2021, 11(1), 37; https://0-doi-org.brum.beds.ac.uk/10.3390/app11010037 - 23 Dec 2020

Cited by 14 | Viewed by 2714

Abstract

This paper presents an autonomous robotic assembly system for Soma cube blocks, which, after observing the individual blocks and their assembled shape, quickly plans and executes the assembly motion sequence that picks up each block and incrementally build the target shape. A multi [...] Read more.

This paper presents an autonomous robotic assembly system for Soma cube blocks, which, after observing the individual blocks and their assembled shape, quickly plans and executes the assembly motion sequence that picks up each block and incrementally build the target shape. A multi stage planner is used to find the suitable assembly solutions, assembly sequences and grip sequences considering various constraints, and re-grasping is used when the block target pose is not directly realizable or the block pose is ambiguous. The suggested system is implemented for a commercial UR5e robotic arm and a novel two degrees of freedom (DOF) gripper capable of in-hand manipulation, which further speeds up the manipulation speed. It was experimentally validated through a public competitive demonstration, where the suggested system completed all assembly tasks reliably with outstanding performance. Full article

(This article belongs to the Special Issue Object Recognition, Robotic Grasping and Manipulation)

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20 pages, 6804 KiB

Open AccessArticle

Scattering or Pushing for Object Singulation in Cluttered Environment: Case Study with Soma Cube

by Muhammad Umair Ahmad Khan, Abid Imran, Sanghwa Kim, Hyunho Hwang, Ji Yeong Lee, Sungon Lee and Byung-Ju Yi

Appl. Sci. 2020, 10(24), 9153; https://0-doi-org.brum.beds.ac.uk/10.3390/app10249153 - 21 Dec 2020

Cited by 1 | Viewed by 2841

Abstract

This paper proposes a hybrid singulation approach combining dynamic scattering and pushing techniques. Using the impulse-based dynamic model, a guideline is provided to decide whether scattering or pushing is conducted for object singulation. The Soma cube consisting of seven blocks is used as [...] Read more.

This paper proposes a hybrid singulation approach combining dynamic scattering and pushing techniques. Using the impulse-based dynamic model, a guideline is provided to decide whether scattering or pushing is conducted for object singulation. The Soma cube consisting of seven blocks is used as the test example. The target is to singulate all the blocks. The dynamic scattering technique was initially applied to separate blocks in the formation. However, scattering alone does not provide target singulation in all the cases. So we combine the quasi-static pushing technique to complete the singulation of all the blocks. In pushing, image segmentation based on principal component analysis (PCA) algorithm was employed to singulate multiple blocks in clutter and prehensile manipulation was used to remove isolated blocks. Several 2-D formations of the Soma cube are used as the test cases. To validate the effectiveness of our approach, we have conducted comparative analysis which clearly shows that the hybrid singulation achieves singulation in much less time as compared to the pure pushing approach. Full article

(This article belongs to the Special Issue Object Recognition, Robotic Grasping and Manipulation)

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19 pages, 4040 KiB

Open AccessArticle

Unified Software Platform for Intelligent Home Service Robots

by Jae-Bong Yi, Taewoong Kang, Dongwoon Song and Seung-Joon Yi

Appl. Sci. 2020, 10(17), 5874; https://0-doi-org.brum.beds.ac.uk/10.3390/app10175874 - 25 Aug 2020

Cited by 11 | Viewed by 3525

Abstract

Although the mobile manipulation capability is crucial for a service robot to perform physical work without human support, the long-term autonomous operation of such a mobile manipulation robot in a real environment is still a tremendously difficult task. In this paper, we present [...] Read more.

Although the mobile manipulation capability is crucial for a service robot to perform physical work without human support, the long-term autonomous operation of such a mobile manipulation robot in a real environment is still a tremendously difficult task. In this paper, we present a modular, general purpose software framework for intelligent mobile manipulation robots that can interact with humans using complex human speech commands; navigate smoothly in tight indoor spaces; and finally detect and manipulate various household objects and pieces of furniture autonomously. The suggested software framework is designed to be easily transferred to different home service robots, which include the Toyota Human Support Robot (HSR) and our Modular Service Robot-1 (MSR-1) platforms. It has successfully been used to solve various home service tasks at the RoboCup@Home and World Robot Summit international service robot competitions with promising results. Full article

(This article belongs to the Special Issue Object Recognition, Robotic Grasping and Manipulation)

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12 pages, 13567 KiB

Open AccessArticle

Development of an Anthropomorphic Prosthetic Hand with Underactuated Mechanism

by Wooseok Ryu, Youngjin Choi, Yong Je Choi, Yeong Geol Lee and Sungon Lee

Appl. Sci. 2020, 10(12), 4384; https://0-doi-org.brum.beds.ac.uk/10.3390/app10124384 - 25 Jun 2020

Cited by 14 | Viewed by 4002

Abstract

An anthropomorphic prosthetic hand for wrist or forearm amputees is developed herein. The prosthetic hand was designed with an underactuated mechanism, which makes self-adaptive grasping possible, as well as natural motions such as flexion and extension. The finger and thumb modules were designed [...] Read more.

An anthropomorphic prosthetic hand for wrist or forearm amputees is developed herein. The prosthetic hand was designed with an underactuated mechanism, which makes self-adaptive grasping possible, as well as natural motions such as flexion and extension. The finger and thumb modules were designed with four degrees of freedom by motions of the distal interphalangeal, proximal interphalangeal, and metacarpophalangeal joints. In this research, we pursued several novel trials in prosthetic hand design. By using two four-bar linkages composed of a combination of linkages and gears for coupling joints at each finger, it was possible to make a compact design, and the linkage has advantages such as accurate positioning, uniform power transmission, and high payload. Also, by using constant-velocity joints, torque is transferred to finger modules regardless of adduction/abduction motions. In addition, adduction/abduction and self-adaptive grasping motions are passively realized using torsional springs. The developed prosthetic hand was fabricated with a weight of 475 g and a human hand size of 175 mm. Experiments with diverse objects showed its good functionality. Full article

(This article belongs to the Special Issue Object Recognition, Robotic Grasping and Manipulation)

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16 pages, 1065 KiB

Open AccessArticle

Input-to-State Stability of Variable Impedance Control for Robotic Manipulator

by Junho Park and Youngjin Choi

Appl. Sci. 2020, 10(4), 1271; https://0-doi-org.brum.beds.ac.uk/10.3390/app10041271 - 13 Feb 2020

Cited by 5 | Viewed by 2877

Abstract

Variable impedance control has been required to perform a variety of interactive tasks in contact with environments. In some cases, the time-varying stiffness matrix of the impedance model can be used to achieve high performance for uneven contact tasks. In the paper, two [...] Read more.

Variable impedance control has been required to perform a variety of interactive tasks in contact with environments. In some cases, the time-varying stiffness matrix of the impedance model can be used to achieve high performance for uneven contact tasks. In the paper, two sufficient conditions are proposed to ensure the input-to-state stability (ISS) irrespective of time-varying stiffness. Furthermore, the update rule of the stiffness is also suggested in such a way that the asymptotic stability is guaranteed under certain region conditions. Even when the update rule is not applied, the ISS is at least assured. In other words, the error is always bounded only if the external force/torque is bounded. In detail, two sufficient conditions offer the lower bound of stiffness and the upper bound of its time derivative. Simulation results show that the ISS of variable impedance control is achieved if the proposed sufficient conditions are satisfied. Also, we can confirm the asymptotic behavior in the simulation when the stiffness is updated according to the given rule. Full article

(This article belongs to the Special Issue Object Recognition, Robotic Grasping and Manipulation)

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11 pages, 5190 KiB

Open AccessArticle

Object-Independent Grasping in Heavy Clutter

by HyunJun Jo and Jae-Bok Song

Appl. Sci. 2020, 10(3), 804; https://0-doi-org.brum.beds.ac.uk/10.3390/app10030804 - 23 Jan 2020

Cited by 6 | Viewed by 2696

Abstract

When grasping objects in a cluttered environment, a key challenge is to find appropriate poses to grasp effectively. Accordingly, several grasping algorithms based on artificial neural networks have been developed recently. However, these methods require large amounts of data for learning and high [...] Read more.

When grasping objects in a cluttered environment, a key challenge is to find appropriate poses to grasp effectively. Accordingly, several grasping algorithms based on artificial neural networks have been developed recently. However, these methods require large amounts of data for learning and high computational costs. Therefore, we propose a depth difference image-based bin-picking (DBP) algorithm that does not use a neural network. DBP predicts the grasp pose from the object and its surroundings, which are obtained through depth filtering and clustering. The object region is estimated by the density-based spatial clustering of applications with noise (DBSCAN) algorithm, and a depth difference image (DDI) that represents the depth difference between adjacent areas is defined. To validate the performance of the DBP scheme, bin-picking experiments were conducted on 45 different objects, along with bin-picking experiments in heavy clutters. DBP exhibited success rates of 78.6% and 83.3%, respectively. In addition, DBP required a computational time of approximately 1.4 s for each attempt. Full article

(This article belongs to the Special Issue Object Recognition, Robotic Grasping and Manipulation)

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19 pages, 5379 KiB

Open AccessArticle

Integrated Motion Planning for Assembly Task with Part Manipulation Using Re-Grasping

by Ahmad Ali and Ji Yeong Lee

Appl. Sci. 2020, 10(3), 749; https://0-doi-org.brum.beds.ac.uk/10.3390/app10030749 - 21 Jan 2020

Cited by 5 | Viewed by 2646

Abstract

This paper presents an integrated planner based on rapidly exploring random tree (RRT) for an assembly task with possible re-grasping. Given multiple grasp poses for the part to assemble, the planner chooses candidate grasp poses considering the environment (including the partially finished assembly) [...] Read more.

This paper presents an integrated planner based on rapidly exploring random tree (RRT) for an assembly task with possible re-grasping. Given multiple grasp poses for the part to assemble, the planner chooses candidate grasp poses considering the environment (including the partially finished assembly) in addition to the initial and final poses of the part. Orientation graph search based re-grasping approach is proposed for part manipulation which is needed when there is no feasible grasp solution for a part between its initial and final poses. Orientation graph search helps finding a series of the intermediate poses of the part needed between its initial and final poses so that robot can grasp and assemble it without interfering the pre-assembled parts. Then while extending the tree, the algorithm tries to connect the tree to a robot configuration with a chosen candidate grasp pose. Also, since the task space undergoes changes at each step of the assembly task, a node or edge in the tree can become in collision during the assembly of later parts, making the node in collision and its descendant nodes disconnected from the whole tree. To handle this, Two stage extended RRT strategy is proposed. The disconnected parts of the main tree are put into forest, and attempts are made to re-connect the tree in the forest to main tree while extending the main tree, thus making it possible to use the disconnected part again. The algorithm is implemented in Linux based system using C++. The proposed algorithm is demonstrated experimentally using UR5e robot manipulator by assembling the soma puzzle pieces in different 3D formations. Full article

(This article belongs to the Special Issue Object Recognition, Robotic Grasping and Manipulation)

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21 pages, 41712 KiB

Open AccessArticle

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

by Long Kang, Jong-Tae Seo, Sang-Hwa Kim, Wan-Ju Kim and Byung-Ju Yi

Appl. Sci. 2019, 9(24), 5266; https://0-doi-org.brum.beds.ac.uk/10.3390/app9245266 - 04 Dec 2019

Cited by 18 | Viewed by 10705

Abstract

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 [...] Read more.

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. Full article

(This article belongs to the Special Issue Object Recognition, Robotic Grasping and Manipulation)

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