Robotics

14 pages, 1707 KiB

Open AccessEditor’s ChoiceReview

A Review of the Literature on the Lower-Mobility Parallel Manipulators of 3-UPU or 3-URU Type

by Raffaele Di Gregorio

Robotics 2020, 9(1), 5; https://doi.org/10.3390/robotics9010005 - 13 Jan 2020

Cited by 22 | Viewed by 6736

Various 3-UPU architectures feature two rigid bodies connected to one another through three kinematic chains (limbs) of universal–prismatic–universal (UPU) type. They were first proposed in the last decade of the 20th century and have animated discussions among researchers for more-or-less two decades. Such [...] Read more.

Various 3-UPU architectures feature two rigid bodies connected to one another through three kinematic chains (limbs) of universal–prismatic–universal (UPU) type. They were first proposed in the last decade of the 20th century and have animated discussions among researchers for more-or-less two decades. Such discussions brought to light many features of lower-mobility parallel manipulators (PMs) that were unknown until then. The discussions also showed that such architectures may be sized into translational PMs, parallel wrists, or even reconfigurable (metamorphic) PMs. Even though commercial robots with these architectures have not yet been built, the interest in them remains. Consequently, a review of the literature on these architectures, highlighting their contribution to the progress of lower-mobility PM design, is still of interest for the scientific community. This paper aims at presenting a critical review of the results that have been obtained up until now. Full article

(This article belongs to the Special Issue Kinematics and Robot Design II, KaRD2019)

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25 pages, 3078 KiB

Open AccessEditor’s ChoiceReview

Human–Robot Collaboration in Manufacturing Applications: A Review

by Eloise Matheson, Riccardo Minto, Emanuele G. G. Zampieri, Maurizio Faccio and Giulio Rosati

Robotics 2019, 8(4), 100; https://doi.org/10.3390/robotics8040100 - 6 Dec 2019

Cited by 404 | Viewed by 44373

Abstract

This paper provides an overview of collaborative robotics towards manufacturing applications. Over the last decade, the market has seen the introduction of a new category of robots—collaborative robots (or “cobots”)—designed to physically interact with humans in a shared environment, without the typical barriers [...] Read more.

This paper provides an overview of collaborative robotics towards manufacturing applications. Over the last decade, the market has seen the introduction of a new category of robots—collaborative robots (or “cobots”)—designed to physically interact with humans in a shared environment, without the typical barriers or protective cages used in traditional robotics systems. Their potential is undisputed, especially regarding their flexible ability to make simple, quick, and cheap layout changes; however, it is necessary to have adequate knowledge of their correct uses and characteristics to obtain the advantages of this form of robotics, which can be a barrier for industry uptake. The paper starts with an introduction of human–robot collaboration, presenting the related standards and modes of operation. An extensive literature review of works published in this area is undertaken, with particular attention to the main industrial cases of application. The paper concludes with an analysis of the future trends in human–robot collaboration as determined by the authors. Full article

(This article belongs to the Special Issue Advances in Italian Robotics)

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21 pages, 2462 KiB

Open AccessEditor’s ChoiceArticle

Nonlinear Model Predictive Control for Mobile Robot Using Varying-Parameter Convergent Differential Neural Network

by Yingbai Hu, Hang Su, Longbin Zhang, Shu Miao, Guang Chen and Alois Knoll

Robotics 2019, 8(3), 64; https://doi.org/10.3390/robotics8030064 - 31 Jul 2019

Cited by 27 | Viewed by 9936

Abstract

The mobile robot kinematic model is a nonlinear affine system, which is constrained by velocity and acceleration limits. Therefore, the traditional control methods may not solve the tracking problem because of the physical constraint. In this paper, we present the nonlinear model predictive [...] Read more.

The mobile robot kinematic model is a nonlinear affine system, which is constrained by velocity and acceleration limits. Therefore, the traditional control methods may not solve the tracking problem because of the physical constraint. In this paper, we present the nonlinear model predictive control (NMPC) algorithm to track the desired trajectory based on neural-dynamic optimization. In the proposed algorithm, the NMPC scheme utilizes a new neural network named the varying-parameter convergent differential neural network (VPCDNN) which is a Hopfifield-neural network structure with respect to the differential equation theory to solve the quadratic programming (QP) problem. The new network structure converges to the global optimal solution and it is more efficient than traditional numerical methods. In the simulation, we verify that the proposed method is able to successfully track reference trajectories with a two-wheel mobile robot. The experimental validation has been conducted in simulation and the results show that the proposed method is able to precisely track the trajectory maintaining a high robustness based on the VPCDNN solver. Full article

(This article belongs to the Special Issue Robotics and Automation Engineering)

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24 pages, 2687 KiB

Open AccessEditor’s ChoiceArticle

Vision-Based Assisted Tele-Operation of a Dual-Arm Hydraulically Actuated Robot for Pipe Cutting and Grasping in Nuclear Environments

by Manuel Bandala, Craig West, Stephen Monk, Allahyar Montazeri and C. James Taylor

Robotics 2019, 8(2), 42; https://doi.org/10.3390/robotics8020042 - 4 Jun 2019

Cited by 44 | Viewed by 11669

Abstract

This article investigates visual servoing for a hydraulically actuated dual-arm robot, in which the user selects the object of interest from an on-screen image, whilst the computer control system implements via feedback control the required position and orientation of the manipulators. To improve [...] Read more.

This article investigates visual servoing for a hydraulically actuated dual-arm robot, in which the user selects the object of interest from an on-screen image, whilst the computer control system implements via feedback control the required position and orientation of the manipulators. To improve on the current joystick direct tele-operation commonly used as standard in the nuclear industry, which is slow and requires extensive operator training, the proposed assisted tele-operation makes use of a single camera mounted on the robot. Focusing on pipe cutting as an example, the new system ensures that one manipulator automatically grasps the user-selected pipe, and appropriately positions the second for a cutting operation. Initial laboratory testing (using a plastic pipe) shows the efficacy of the approach for positioning the manipulators, and suggests that for both experienced and inexperienced users, the task is completed significantly faster than via tele-operation. Full article

(This article belongs to the Special Issue Robotics in Extreme Environments)

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14 pages, 14306 KiB

Open AccessEditor’s ChoiceArticle

Extending the Application of an Assistant Personal Robot as a Walk-Helper Tool

by Jordi Palacín, Eduard Clotet, Dani Martínez, David Martínez and Javier Moreno

Robotics 2019, 8(2), 27; https://doi.org/10.3390/robotics8020027 - 10 Apr 2019

Cited by 24 | Viewed by 6550

Abstract

This paper presents the application of a mobile robot designed as an Assistant Personal Robot (APR) as a walk-helper tool. The hypothesis is that the height and weight of this mobile robot can be used also to provide a dynamic physical support and [...] Read more.

This paper presents the application of a mobile robot designed as an Assistant Personal Robot (APR) as a walk-helper tool. The hypothesis is that the height and weight of this mobile robot can be used also to provide a dynamic physical support and guidance to people while they walk. This functionality is presented as a soft walking aid at home but not as a substitute of an assistive cane or a walker device, which may withstand higher weights and provide better stability during a walking. The APR operates as a walk-helper tool by providing user interaction using the original arms of the mobile robot and by using the onboard sensors of the mobile robot in order to avoid obstacles and guide the walking through free areas. The results of the experiments conducted with the walk-helper have showed the automatic generation of smooth walking trajectories and a reduction in the number of manual trajectory corrections required to complete a walking displacement. Full article

(This article belongs to the Special Issue Recent Advances on Physical Agents)

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15 pages, 7652 KiB

Open AccessEditor’s ChoiceArticle

V2SOM: A Novel Safety Mechanism Dedicated to a Cobot’s Rotary Joints

by Younsse Ayoubi, Med Amine Laribi, Said Zeghloul and Marc Arsicault

Robotics 2019, 8(1), 18; https://doi.org/10.3390/robotics8010018 - 6 Mar 2019

Cited by 10 | Viewed by 6824

Abstract

Unlike “classical” industrial robots, collaborative robots, known as cobots, implement a compliant behavior. Cobots ensure a safe force control in a physical interaction scenario within unknown environments. In this paper, we propose to make serial robots intrinsically compliant to guarantee safe physical human–robot [...] Read more.

Unlike “classical” industrial robots, collaborative robots, known as cobots, implement a compliant behavior. Cobots ensure a safe force control in a physical interaction scenario within unknown environments. In this paper, we propose to make serial robots intrinsically compliant to guarantee safe physical human–robot interaction (pHRI), via our novel designed device called V2SOM, which stands for Variable Stiffness Safety-Oriented Mechanism. As its name indicates, V2SOM aims at making physical human–robot interaction safe, thanks to its two basic functioning modes—high stiffness mode and low stiffness mode. The first mode is employed for normal operational routines. In contrast, the low stiffness mode is suitable for the safe absorption of any potential blunt shock with a human. The transition between the two modes is continuous to maintain a good control of the V2SOM-based cobot in the case of a fast collision. V2SOM presents a high inertia decoupling capacity which is a necessary condition for safe pHRI without compromising the robot’s dynamic performances. Two safety criteria of pHRI were considered for performance evaluations, namely, the impact force (ImpF) criterion and the head injury criterion (HIC) for, respectively, the external and internal damage evaluation during blunt shocks. Full article

(This article belongs to the Special Issue Mechanism Design for Robotics)

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14 pages, 528 KiB

Open AccessEditor’s ChoiceArticle

Trajectory Design for Energy Savings in Redundant Robotic Cells

by Paolo Boscariol and Dario Richiedei

Robotics 2019, 8(1), 15; https://doi.org/10.3390/robotics8010015 - 20 Feb 2019

Cited by 15 | Viewed by 6987

Abstract

This work explores the possibility of exploiting kinematic redundancy as a tool to enhance the energetic performance of a robotic cell. The test case under consideration comprises a three-degree-of-freedom Selective Compliance Assembly Robot Arm (SCARA) robot and an additional linear unit that is [...] Read more.

This work explores the possibility of exploiting kinematic redundancy as a tool to enhance the energetic performance of a robotic cell. The test case under consideration comprises a three-degree-of-freedom Selective Compliance Assembly Robot Arm (SCARA) robot and an additional linear unit that is used to move the workpiece during a pick and place operation. The trajectory design is based on a spline interpolation of a sequence of via-points: The corresponding motion of the joints is used to evaluate, through the use of an inverse dynamic model, the actuators effort and the associated power consumption by the robot and by the linear unit. Numerical results confirm that the suggested method can improve both the execution time and the overall energetic efficiency of the cell. Full article

(This article belongs to the Special Issue Mechanism Design for Robotics)

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16 pages, 13321 KiB

Open AccessEditor’s ChoiceArticle

Non-Photorealistic Rendering Techniques for Artistic Robotic Painting

by Lorenzo Scalera, Stefano Seriani, Alessandro Gasparetto and Paolo Gallina

Robotics 2019, 8(1), 10; https://doi.org/10.3390/robotics8010010 - 11 Feb 2019

Cited by 30 | Viewed by 10690

Abstract

In this paper, we present non-photorealistic rendering techniques that are applied together with a painting robot to realize artworks with original styles. Our robotic painting system is called Busker Robot and it has been considered of interest in recent art fairs and international [...] Read more.

In this paper, we present non-photorealistic rendering techniques that are applied together with a painting robot to realize artworks with original styles. Our robotic painting system is called Busker Robot and it has been considered of interest in recent art fairs and international exhibitions. It consists of a six degree-of-freedom collaborative robot and a series of image processing and path planning algorithms. In particular, here, two different rendering techniques are presented and a description of the experimental set-up is carried out. Finally, the experimental results are discussed by analyzing the elements that can account for the aesthetic appreciation of the artworks. Full article

(This article belongs to the Special Issue Mechanism Design for Robotics)

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