Search Results (5)

Over the last decade, large-scale antennas have been developed to enhance precise blue force tracking and improve situational awareness. In general, such large-scale antennas, ranging from 1 to up to 10 m, need a specific mechanism that can reconfigure their shapes and morphologies, resulting in stowing and deploying upon the given environment. In parallel, it must be noted that such deployable mechanisms should accommodate a large aperture diameter while ensuring they are lightweight, robust, and structurally rigid to avoid undesired deformations due to the deployment. With these in mind, this work presents a large frustum-shaped deployable antenna mechanism with a large aperture diameter of 7.5 m. The deployable mechanism is composed of hierarchical bayes the radial direction at 30° intervals. Twelve bayes in total identify the overall morphology of the deployable antenna, which features a dodecagon. Specifically, the bay is composed of three linkage structures: a six-bar linkage mechanism, a V-folding mechanism, and a single pantograph mechanism. As a result of static and dynamic simulations, it is identified that the mechanism achieves an area-to-mass ratio of 5.003 m²/kg and a safety factor of 323.8 upon deployment. Conclusively, this work demonstrates a strong potential of the deployable antenna mechanism, providing high rigidity and large aperture diameter while ensuring high stability in space environments. Full article

Bioactive surface coatings have retained the attention of researchers and physicians due to their versatility and range of applications in orthopedics, particularly in infection prevention. Antibacterial metal nanoparticles (mNPs) are a promising therapeutic, with vast application opportunities on orthopedic implants. The current research aimed to construct a polyelectrolyte multilayer on a highly porous titanium implant using alternating thin film coatings of chitosan and alginate via the layer-by-layer (LbL) self-assembly technique, along with the incorporation of silver nanoparticles (AgNPs) or titanium dioxide nanoparticles (TiO₂NPs), for antibacterial and osteoconductive activity. These mNPs were characterized for their physicochemical properties using quartz crystal microgravimetry with a dissipation system, nanoparticle tracking analysis, scanning electron microscopy, and atomic force microscopy. Their cytotoxicity and osteogenic differentiation capabilities were assessed using AlamarBlue and alkaline phosphatase (ALP) activity assays, respectively. The antibiofilm efficacy of the mNPs was tested against Staphylococcus aureus. The LbL polyelectrolyte coating was successfully applied to the porous titanium substrate. A dose-dependent relationship between nanoparticle concentration and ALP as well as antibacterial effects was observed. TiO₂NP samples were also less cytotoxic than their AgNP counterparts, although similarly antimicrobial. Together, these data serve as a proof-of-concept for a novel coating approach for orthopedic implants with antimicrobial and osteoconductive properties. Full article

This paper presents a simulation model environment for the popular and low-cost remotely operated vehicle (ROV) BlueROV2 implemented in Simulink™ which has been designed and experimentally validated for benchmark control algorithms for underwater vehicles. The BlueROV2 model is based on Fossen’s equations and includes a kinematic model of the vehicle, the hydrodynamics of vehicle and water interaction, a dynamic model of the thrusters, and, lastly, the gravitational/buoyant forces. The hydrodynamic parameters and thruster model have been validated in a test facility. The benchmark model also includes the ocean current, modeled as constant velocity. The tether connecting the ROV to the top-site facility has been modeled using the lumped mass method and is implemented as a force input to the ROV model. At last, to show the usefulness of the benchmark model, a case study is presented where a BlueROV2 is deployed to inspect an offshore monopile structure. The case study uses a sliding mode controller designed for the BlueROV2. The controller fulfills the design criteria defined for the case study by following the provided trajectory with a low error. It is concluded that the simulator establishes a benchmark for future control schemes for position control and trajectory tracking under the influence of environmental disturbances. Full article

Blue force tracking represents an essential task in the field of military applications. A blue force tracking system provides the location information of their own forces on a map to commanders. For the command post, this results in more efficient operation control with increasing safety. In underground structures (e.g., tunnels or subways), the localisation is challenging due to the lack of GNSS signals. This paper presents a localisation system for military or emergency forces tailored to usage in complex underground structures. In a particle filter, position changes from a dual foot-mounted INS are fused with opportunistic UWB ranges and data from a 3D tunnel model to derive position information. A concept to deal with the absence of UWB infrastructure or 3D tunnel models is illustrated. Recurrent neural network methodologies are applied to cope with different motion types of the operators. The evaluation of the positioning algorithm took place in a street tunnel. If a fully installed infrastructure was available, positioning errors under one metre were reached. The results also showed that the INS can bridge UWB outages. A particle-filter-based approach to UWB anchor mapping is presented, and the first simulation results showed its viability. Full article

This paper presents advances in the development of specialized mobile applications for combat decision support utilizing augmented reality technologies used for the production of contextual data delivered to any tactical smartphone. Handhelds and decision support systems have been present in military operations since the 1990s. Due to the development of hardware and software platforms, smartphones are capable of running complex algorithms for individual soldiers and low-level commander support. The utilization of tactical data (force location, composition, and tasks) in dynamic mobile networks that are accessible anywhere during a mission provides means for the development of situational awareness and decision superiority. These two elements are key factors in 21st-century military operations, as they influence the efficiency of recognition, identification, and targeting. Combat support tools and their analytical capabilities can serve as recon data hubs, but most of all they can support and simplify complex analytical tasks for commanders. These tasks mainly include topographical and tactical orientation within the battlespace. This paper documents the ideas for and construction details of mobile support tools used for supporting the specific operational activities of military personnel during combat and crisis management. The presented augmented reality-based evaluation methods formulate new capabilities for the visualization and identification of military threats, mission planning characteristics, tasks, and checkpoints, which help individuals to orientate within their current situation. The developed software platform, mobile common operational picture (mCOP), demonstrates all research findings and delivers a personalized combat-oriented distributed mobile system, supporting blue-force tracking capabilities and reconnaissance data fusion as well as threat-level evaluations for military and crisis management scenarios. The mission data are further fused with Geographic Information System (GIS) topographical and vector data, supporting terrain evaluations for mission planning and execution. The application implements algorithms for path finding, movement task scheduling, assistance, and analysis, as well as military potential evaluation, threat-level estimation, and location tracking. The features of the mCOP mobile application were designed and organized as mission-critical functions. The presented research demonstrates and proves the usefulness of deploying mobile applications for combat support, situation awareness development, and the delivery of augmented reality-based threat-level analytical data to extend the capabilities and properties of software tools applied for supporting military and border protection operations. Full article