Search

• Perception, cognition and control methods for safe human robot interaction. • Safe hardware and software development, low level admittance controller. • Human aware navigation, virtual collaborative zones. • Psychological factors in human robot interaction. • Robot safety features chronological map. • Systems' theoretic analysis. In the era of industrialization and automation, safety is a critical factor that should be considered during the design and realization of each new system that targets operation in close collaboration with humans. Of such systems are considered personal and professional service robots which collaborate and interact with humans at diverse applications environments. In this collaboration, human safety is an important factor in the wider field of human-robot interaction (HRI) since it facilitates their harmonic coexistence. The paper at hand aims to systemize the recent literature by describing the required levels of safety during human-robot interaction, focusing on the core functions of the collaborative robots when performing specific processes. It is also oriented towards the existing methods for psychological safety during human-robot collaboration and its impact at the robot behaviour, while also discusses in depth the psychological parameters of robots incorporation in industrial and social environments. Based on the existing works on safety features that minimize the risk of HRI, a classification of the existing works into five major categories namely, Robot Perceptions for Safe HRI, Cognition-enabled robot control in HRI, Action Planning for safe navigation close to humans, Hardware safety features, and Societal and Psychological factors is also applied. Finally, the current study further discusses the existing risk assessment techniques as methods to offer additional safety in robotic systems presenting thus a holistic analysis of the safety in contemporary robots, and proposes a roadmap for safety compliance features during the development of a robotic system. [ABSTRACT FROM AUTHOR]

Nowadays, H13 steel is commonly utilized in processes such as pressure die casting, extrusion, and drop forging as well as in tube and glass manufacturing, however with limited manufacturability. The current research focuses on the effects of crucial process-related additive manufacturing parameters on the mechanical behavior of H13 hot work tool steel manufactured by the selective laser melting (SLM) additive manufacturing (AM) technique. The investigated parameters were the scan speed, the laser power, and their output volumetric energy density (VED) on the mechanical and morphological properties utilizing tensile and nanoindentation tests as well as scanning electron microscope (SEM). The results of this study revealed that it is possible to manufacture H13 steel parts with high mechanical performance using the SLM additive manufacturing technique. Specifically, the ultimate tensile strength reached a peak value at 1836 ± 48 MPa, while the yield tensile strength was found at 1468 ± 30 MPa. These parts are comparable to those made with conventional materials. A die part made using SLM was tested in the aluminum extrusion process on an 18 MN extrusion press producing acceptable quality extrudates and verifying its functionality and resilience under the high pressure and temperature of the extrusion process. [ABSTRACT FROM AUTHOR]

One of the main therapeutic problems worldwide is the restoration of cartilaginous lesions in order to prevent osteoarthritis which can lead to heavy and high‐cost joint replacement operations with metal implants. In situations where large cartilage lesions occur, the only solution is the transplantation of autologous cells such as chondrocytes or mesenchymal cells. These transplants require the use of scaffolds that are derived from various animals or even synthetic materials, acting as carriers of the above‐mentioned cells. In the context of this study, an integrated system is introduced aiming to rapidly design and fabricate customized 3D‐printed scaffolds, which are constructed from biomaterials, providing that way a valuable solution to their production as well as eliminating the need for multiple operations. The main idea is the employment of a stereoscopic endoscope during the arthroscopy operation extracting stereoscopic images of the investigated area in order to perform a 3D reconstruction of the cartilage lesion area prior and after the surgeon's operation. The fusion of the preoperative images (magnetic resonance imaging [MRI] for organic tissue and computed tomography [CT] for synthetic phantoms) with the captured stereoscopic images allows the formulation of an appropriate 3D model of the scaffold. In addition, the physical model of the scaffold is manufactured with the aid of a sterilized 3D printer utilizing biomaterials, such as polycaprolactone (PCL), chitosan, etc. Finally, the 3D printed scaffold is impregnated with autologous cells and inserted into the cartilage lesion during the arthroscopy operation saving precious time and reducing the overall rehabilitation cost. [ABSTRACT FROM AUTHOR]

The industrial revolution 4.0 has led to a burst in the development of robotic automation and platforms to increase productivity in the industrial and health domains. Hence, there is a necessity for the design and production of smart and multi-functional tools, which combine several cutting-edge technologies, including additive manufacturing and smart control systems. In the current article, a novel multi-functional biomimetic soft actuator with a pneumatic motion system was designed and fabricated by combining different additive manufacturing techniques. The developed actuator was bioinspired by the natural kinematics, namely the motion mechanism of worms, and was designed to imitate the movement of a human finger. Furthermore, due to its modular design and the ability to adapt the actuator's external covers depending on the requested task, this actuator is suitable for a wide range of applications, from soft (i.e., fruit grasping) or industrial grippers to medical exoskeletons for patients with mobility difficulties and neurological disorders. In detail, the motion system operates with two pneumatic chambers bonded to each other and fabricated from silicone rubber compounds molded with additively manufactured dies made of polymers. Moreover, the pneumatic system offers multiple-degrees-of-freedom motion and it is capable of bending in the range of −180° to 180°. The overall pneumatic system is protected by external covers made of 3D printed components whose material could be changed from rigid polymer for industrial applications to thermoplastic elastomer for complete soft robotic applications. In addition, these 3D printed parts control the angular range of the actuator in order to avoid the reaching of extreme configurations. Finally, the bio-robotic actuator is electronically controlled by PID controllers and its real-time position is monitored by a one-axis soft flex sensor which is embedded in the actuator's configuration. [ABSTRACT FROM AUTHOR]

Selective laser melting (SLM) is one of the most reliable and efficient procedures for Metal Additive Manufacturing (AM) due to the capability to produce components with high standards in terms of dimensional accuracy, surface finish, and mechanical behavior. In the past years, the SLM process has been utilized for direct manufacturing of fully functional mechanical parts in various industries, such as aeronautics and automotive. Hence, it is essential to investigate the SLM procedure for the most commonly used metals and alloys. The current paper focuses on the impact of crucial process-related parameters on the final quality of parts constructed with the Inconel 718 superalloy. Utilizing the SLM process and the Inconel 718 powder, several samples were fabricated using various values on critical AM parameters, and their mechanical behavior as well as their surface finish were examined. The investigated parameters were the laser power, the scan speed, the spot size, and their output Volumetric Energy Density (VED), which were applied on each specimen. The feedstock material was inspected using Scanning Electron Microscopy (SEM), Energy-dispersive X-ray spectroscopy (EDX) analysis, and Particle-size distribution (PSD) measurements in order to classify the quality of the raw material. The surface roughness of each specimen was evaluated via multi-focus imaging, and the mechanical performance was quantified utilizing quasi-static uniaxial tensile and nanoindentation experiments. Finally, regression-based models were developed in order to interpret the behavior of the AM part's quality depending on the process-related parameters. [ABSTRACT FROM AUTHOR]

The importance of construction automation has grown worldwide, aiming to deliver new machineries for the automation of roads, tunnels, bridges, buildings and earth-work construction. This need is mainly driven by (i) the shortage and rising costs of skilled workers, (ii) the tremendous increased needs for new infrastructures to serve the daily activities and (iii) the immense demand for maintenance of ageing infrastructure. Shotcrete (sprayed concrete) is increasingly becoming popular technology among contractors and builders, as its application is extremely economical and flexible as the growth in construction repairs in developed countries demand excessive automation of concrete placement. Even if shotcrete technology is heavily mechanized, the actual application is still performed manually at a large extend. RoBétArméEuropean project targets the Construction 4.0 transformation of the construction with shotcrete with the adoption of breakthrough technologies such as sensors, augmented reality systems, high-performance computing, additive manufacturing, advanced materials, autonomous robots and simulation systems, technologies that have already been studied and applied so far in Industry 4.0. The paper at hand showcases the development of a novel robotic system with advanced perception, cognition and digitization capabilities for the automation of all phases of shotcrete application. In particular, the challenges and barriers in shotcrete automation are presented and the RoBétArmésuggested solutions are outlined. We introduce a basic conceptual architecture of the system to be developed and we demonstrate the four application scenarios on which the system is designated to operate., Competing Interests: No competing interests were disclosed., (Copyright: © 2024 Kostavelis I et al.)

In the last decade, the development of customized biodegradable scaffolds and implants has attracted increased scientific interest due to the fact that additive manufacturing technologies allow for the rapid production of implants with high geometric complexity constructed via commercial biodegradable polymers. In this study, innovative designs of tibial scaffold in form of bone-brick configuration were developed to fill the bone gap utilizing advanced architected materials and bio-inspired diffusion canals. The architected materials and canals provide high porosity, as well as a high surface area to volume ratio in the scaffold facilitating that way in the tissue regeneration process and in withstanding the applied external loads. The cellular structures applied in this work were the Schwarz Diamond (SD) and a hybrid SD&FCC hybrid cellular material, which is a completely new architected material that derived from the combination of SD and Face Centered Cubic (FCC) structures. These designs were additively manufactured utilizing two biodegradable materials namely Polylactic acid (PLA) and Polycaprolactone (PCL), using the Fused Filament Fabrication (FFF) technique, in order to avoid the surgery, for the scaffold's removal after the bone regeneration. Furthermore, the additively manufactured scaffolds were examined in terms of compatibility and assembly with the bone's physical model, as well as, in terms of mechanical behavior under realistic static loads. In addition, non-linear finite element models (FEMs) were developed based on the experimental data to accurately simulate the mechanical response of the examined scaffolds. The Finite Element Analysis (FEA) results were compared with the experimental response and afterwards the stress concentration regions were observed and identified. Τhe proposed design of scaffold with SD&FCC lattice structure made of PLA material with a relative density of 20% revealed the best overall performance, showing that it is the most suitable candidate for further investigation (in-vivo test, clinical trials, etc.) and commercialization., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Ltd. All rights reserved.)