68 research outputs found
Beyond self-assembly: Mergeable nervous systems, spatially targeted communication, and supervised morphogenesis for autonomous robots
No full textThe study of self-assembling robots represents a promising strand within the emerging field of modular robots research. Self-assembling robots have the potential to autonomously adapt their bodies to new tasks and changing environments long after their initial deployment by forming new or reorganizing existing physical connections to peer robots. In previous research, many approaches have been presented to enable self-assembling robots to form composite morphologies. Recent technological advances have also increased the number of robots able to form such morphologies by at least two orders of magnitude. However, to date, composite robot morphologies have not been able to solve real-world tasks nor have they been able to adapt to changing conditions entirely without human assistance or prior knowledge.In this thesis, we identify three reasons why self-assembling robots may not have been able to fully unleash their potential and propose appropriate solutions. First, composite morphologies are not able to show sensorimotor coordination similar to those seen in their monolithic counterparts. We propose "mergeable nervous systems" -- a novel methodology that unifies independent robotic units into a single holistic entity at the control level. Our experiments show that mergeable nervous systems can enable self-assembling robots to demonstrate feats that go beyond those seen in any engineered or biological system. Second, no proposal has been tabled to enable a robot in a decentralized multirobot system select its communication partners based on their location. We propose a new form of highly scalable mechanism to enable "spatially targeted communication" in such systems. Third, the question of when and how to trigger a self-assembly process has been ignored by researchers to a large extent. We propose "supervised morphogenesis" -- a control methodology that is based on spatially targeted communication and enables cooperation between aerial and ground-based self-assembling robots. We show that allocating self-assembly related decision-making to a robot with an aerial perspective of the environment can allow robots on the ground to operate in entirely unknown environments and to solve tasks that arise during mission time. For each of the three propositions put forward in this thesis, we present results of extensive experiments carried out on real robotic hardware. Our results confirm that we were able to substantially advance the state of the art in self-assembling robots by unleashing their potential for morphological adaptation through enhanced sensorimotor coordination and by improving their overall autonomy through cooperation with aerial robots.Doctorat en Sciences de l'ingénieur et technologieinfo:eu-repo/semantics/nonPublishe
The Future of Critical Metals in Electric Vehicles: Impact of The Exponentially Increasing Number of Electric Vehicles On The Supply of Critical Metals
No full textClimate change stands as a monumental environmental challenge confronting the world today, with ongoing global manifestations. Within the transportation sector, the carbon-intense essence of petroleum-powered vehicles, finite fossil fuel reserves, and strides in technologies such as batteries, fuel cells, power electronics, and electric motors have expedited the integration of electric vehicles (EVs) into the conventional automobile market.The escalating demand for crucial metals within renewable energy technology sectors has raised alarms regarding supply chain security. It is imperative to fortify the sustained and secure provision of these pivotal metals to ensure the forthcoming viability of EVs. Numerous nations have committed to achieving net-zero emissions by 2050, intensifying the future prominence of renewables, and underscoring the significance of securing metal supplies for EVs to meet the 2050 demand amid competing technological contenders.Multiple knowledge gaps and challenges encompass the repercussions of EV proliferation on essential metal resources. Prevailing studies on metal scarcity focus on various scenarios, yet few target the exponentially surging demand for these metals stemming from the EV surge. While geological reserve perspectives have scrutinized metal criticality for EVs, this approach lacks a comprehensive panorama, neglecting influential factors such as geopolitics and competing demand. Furthermore, there exists scant exploration of alternative remedies to diminish reliance on critical metals within EVs and their consequences for metal supply chains. The feasibility of these alternatives hinges on their impact on vehicular performance, a determinant factor for broad acceptance.The primary objective of this research is to address the inquiry: "How does the rapid proliferation of electric vehicles affect the availability of vital metals, and what strategies can be adopted to alleviate potential supply impediments?"This research pursues a four-tier approach. Initial efforts involve delineating criticality for EVs and devising an analytical framework that encompasses diverse perspectives beyond geological reserves. A comprehensive review identifies socio-technical metrics instrumental in assessing metal criticality and their contributions to EV-related criticality. This informs the development of an analytical model, rooted in established frameworks, to evaluate metal criticality for EVs. The model then undergoes validation through expert interviews.Subsequently, the research identifies potential bottlenecks in critical metal supply. Essential metals for EV functioning are identified through literature analysis. Building upon prior work by Habib et al., the research delves into geopolitical reserves and integrates future demand scenarios. Each metal within scope undergoes individual analysis, considering geopolitics and competitive demand, utilizing literature reviews to uncover potential supply bottlenecks by 2050.The third stage concentrates on recognizing critical metals from the analytical model results and outlining alternative strategies to alleviate supply bottlenecks. Insights from academic and industry experts, garnered through interviews, illuminate the feasibility of alternative technologies and their metal consumption implications. Varied battery configurations and trade-offs are explored, employing a semi-structured interview approach to ensure thorough data capture.Lastly, the research aspires to actualize alternative pathways to mitigate prospective supply bottlenecks. This involves examining existing practices that imperil suggested solutions and probing promising remedies to these challenges. The technological readiness of these solutions is gauged, considering their effects on EV design and performance. Policy approaches by global leaders, coupled with identified bottlenecks and solutions, inform actionable recommendations.The pivotal factors impacting metal criticality for EVs encompass Geological Reserve availability to meet 2050 EV demand, Competing Demand Sectors, and a spectrum of Political, Economic, Social, Technological, Environmental, and Legal factors. An analytical model is formulated to evaluate metal criticality through each of these lenses. Key metals identified as vital for EV functionality are Lithium, Nickel, Cobalt, Copper, Aluminium, and Rare Earth Metals (REES).From the analytical results, potential supply bottlenecks emerge for Lithium, Nickel, Cobalt, and REEs, stemming from diverse combinations of factors within the model. Expert interviews unearth alternative paths to circumvent these bottlenecks, including substituting REE-containing Permanent Magnet Synchronous (PSM) motors with other technologies, short-term adoption of Lithium Iron Phosphate (LFP) and Lithium Manganese Oxide (LMO) batteries, and long-term integration of alternative battery chemistries like Sodium-ion, Potassium-ion, and Solid-State Electrolyte batteries.The readiness of these technologies is evaluated, alongside scrutiny of policies regarding Critical Raw Material supply and Net-Zero emissions, as observed in global leader initiatives such as the European Union. Drawing from this analysis, a compilation of recommendations is outlined for Global policymakers, EV manufacturers, and EV users. These suggestions seek to accelerate the integration of these alternative technologies within the Electric Vehicle Industry. The proposed strategies to veer away from metals susceptible to supply bottlenecks are summarized, culminating in practical recommendations for stakeholders, manufacturers, and policymakers.Electrical Engineering | Sustainable Energy Technolog
Influence of Parametric Modelling of Wing Subsystems on the Aircraft Design and Performance
No full textAircraft design methodologies have been significantly developing from the past few years with the advancements in knowledge based techniques. These methods enable the storage of design knowledge and rules, and reuse them to create different types of designs, thus preventing the designer to perform repetitive tasks. Tasks such as parametric modelling of components, such as the aircraft wing can be automated by storing the modelling processes and the design rules in a knowledge base. With this process, variants of the wing with different geometric parameters can then be generated in a short duration by simply varying certain top-level requirements. It is necessary to extend these design techniques to model aircraft systems in the conceptual design stage. This, not only decreases the time of design realisation but also presents a scope to assess the effects of various inter-dependencies due to systems and make appropriate changes, in the early stages of aircraft design. Developing and demonstrating a framework which aids to assess the influence of the wing subsystems, namely the flight control actuators, fuel tanks and anti-ice elements; on the aircraft design and performance in the conceptual design stage is the aim of the thesis. This thesis presents a combination of physics based and knowledge based design methodologies to size the wing subsystems and position them in the airframe. Consequently, the methods are integrated into the conceptual aircraft design process to enable multidisciplinary design with supporting domains. The methods are aimed to aid the design of conventional systems architectures and More Electric Aircraft (MEA) systems architectures as well. With these methodologies, the Systems Model Generator (SMG) application is developed in Python to facilitate semi-automatic wing subsystems sizing and orientation in the airframe based on top-level aircraft requirements, initial aircraft design parameters and system specific parameters. The subsystem models generated with the proposed methodology for short-medium range civil transport aircraft are verified and validated as well. Knowledge based systems and subsystems selection are implemented to facilitate semi-automated systems, subsystems and architecture selection, based on the aircraft configuration and systems specific requirements. Methods for automatic iterative fuel tanks sizing and intersection detection are implemented to further reduce the overall design time and make the tool more suitable for integrated sizing.With the multidisciplinary design framework, the conceptual parametric models, volume, mass, power consumption and position of the subsystems in the airframe are generated and propagated in the conceptual aircraft design stage; thus bridging the conceptual and the preliminary design stages. In the proposed framework, the domains of aircraft design generation, systems selection and sizing, subsystems selection and sizing, engine sizing and mission simulation are considered for the multidisciplinary design process. The domains are integrated with the DLR CPACS-RCE framework. A case study to demonstrate the process of integrated parametric subsystems sizing of the aircraft, with the proposed framework is presented. The aim of this case study is to assess the influence of the MEA systems architecture relative to the conventional systems architecture for a short-medium range transport aircraft, similar to the Airbus A320-200. In this case study, the quantitative influence of the subsystems' parameters on the aircraft design and performance parameters is determined and analysed. The subsystems' parameters constitute the mass, power consumption, volume and location of the subsystems in the airframe and the aircraft design parameters constitute the aircraft masses such as the overall empty mass and the fuel mass for the mission. The generation and propagation of the design and performance parameters of the aircraft through each domain of the framework are presented and analysed as well with the case study. In this case study, it is observed that the MEA systems architecture results in a lower mission fuel mass relative to the conventional systems architecture by nearly 2.3\%. Furthermore, these results are compared with literature and observed to be in the similar range of 2-7\%. Thus, the validated aircraft design framework presented in this thesis enables to substantially increases and propagate the design knowledge of aircraft systems, in the early design stages.AGILEAerospace Engineerin
Si-air Battery: Alkaline cell modelling in MATLAB (Simscape)
No full textRenewable energy sources (RES) such as Solar and Wind energy rely on the availability of natural resources like sunlight in the case of Solar and wind speed in the case of Wind energy generation which is variable in nature. There are periods where there is excess energy production than needed and periods of energy shortage where not enough energy is produced to meet the demand. To mitigate this mismatch, a short term solution is to use batteries in order to store energy at times where energy production is more than the energy demand. This stored energy would be later used at times where energy production is low and meet the energy demand. However, the current battery technology is still novel for this application making it uneconomical when compared to current energy infrastructure of using power plants. The current battery market is held by Li-ion batteries which uses lithium as a raw material which is a rare earth material. In 2009, a battery cell utilizing Si as its anode and air as its cathode was discovered. As this system relies on two of the most abundant elements in the earth's crust which is silicon and oxygen and has much higher theoretical energy density than Li-ion batteries, it has become a growing area of research and development. Battery models are created to simulate battery operations based on empirical formulas and electrochemical reactions taking place in the battery. Development of these models are very critical as they provide results and optimum condition evaluations much faster than physical testing with minimal resources. A battery model for the alkaline Si-air battery which utilizes KOH as the cell electrolyte is developed in Simscape (MATLAB) as part of this thesis. The modelling parameters are also subjected various physical conditions such as varying electrolyte concentration and change in electrode materials and the variation is investigated for model validation to study whether changing physical conditions of the Si-air cell has an effect on the modelling cell parameters. It is supported with experimental results obtained from discharging a fabricated Si-air cell. It was concluded that there are cell parameters which are dependent only on the state of charge (SOC) of the cell and one cell parameter that is a function of both the SOC as well as the discharge profile of the cell. The fabricated Si-air cell gives higher open-circuit potential (OCP) values than what was reported constant 1.4 V in literature which is speculated to be due to the usage of a 99% Aluminum and 1% Silicon (Al:Si) back contact layer. Average OCPs ranging from 1.5 V to 1.45 V which varies due to change in electrolyte (KOH) concentration is achieved. The MATLAB battery block is calibrated to be integrated with energy system models as a Si-air battery.Si-air BatteryElectrical Engineering | Sustainable Energy Technolog
Hybrid Key Management Scheme for Secure AMI Communications
No full textAbstractAdvanced Metering Infrastructure (AMI) is an essential attribute of Smart Grid. To ensure secure communication for smart metering one must ensure that the data which is sent or received is authorized and confidential. This article deals with a hybrid encryption scheme for unicast, multicast and broadcast communication in AMI. To ensure confidentiality, integrity and authenticity, a Key Management Scheme (KMS) for hybrid communication modes is proposed. The proposed scheme provides excellent level of security and reduces the computational load on Smart Meter (SM)
Design and development of open-source, multi-purpose wire arc additive manufacturing machine
No full textFunding Information:
Open access funding provided by FCT|FCCN (b-on). Nithin Joseph Reddy Sagili Arthur received funding from Fundação para a Ciência e a Tecnologia (FCT) for its financial support via the PhD grant 2022.10356.BD. Lei Liu received the financial support from the China Scholarship Council Grant No. 202208420052. The authors also received funding by national funds from FCT—Fundação para a Ciência e a Tecnologia, I.P., in the scope of the project’s LA/P/0037/2020, UIDP/50025/2020, and UIDB/50025/2020 of the Associate Laboratory Institute of Nanostructures, Nanomodelling and Nanofabrication – i3 N.
Publisher Copyright:
© The Author(s) 2025.Wire arc additive manufacturing (WAAM) is a promising technology offering capabilities of high deposition rate and low processing and equipment setup cost and the possibility to create components with moderate geometrical complexity. However, wide scale industrialization of this technology is constrained by its complex thermal signature which demands an interdisciplinary approach of integrating auxiliary technologies aiming at controlling and monitoring the process often requiring costly upgrades of ancillary systems. These challenges can be addressed by developing flexible and adaptable WAAM systems that incorporate open-source solutions for developing innovative and customized auxiliary add-ons mitigating proprietary barriers and scale-up expenditures. In this work, we present the design and construction of a scalable WAAM machine featuring three-axis rectilinear motion system with a working envelope suited for small- to medium-sized components. The system integrates a customized weld torch and multiple wire feeder utilizing widely available materials to ensure functionality and cost-effectiveness. An open-source 32-bit control board is employed to achieve coordinated operation of multiple systems. A detailed assessment and selection criteria of various motion control hardware is provided. Additionally, pioneering summary of control boards with significant potential for expansion into metal additive manufacturing is also presented. To validate the machine functionality, multi-layer deposition along X–Z and multi-bead deposition along X–Y axes were conducted. These results demonstrate the seamless synchronization of the motion control, welder, and wire feeder systems, achieving defect-free depositions. Conductive and radiative electromagnetic interference mitigation measures are detailed, providing a practical guidance to simplify the development of customizable WAAM machines.publishersversionpublishe
Refractive index engineering of poly (vinyl alcohol)/Li2ZnO2 nanocomposites: Effect of filler content and annealing temperature
No full textSpatially targeted communication and self-assembly
No full textWe introduce spatially targeted communication - a communication method for multirobot systems. This method allows an individual message sending robot to isolate selected message recipient robots based on their spatial location. The recipient robots can then be sent information targeted solely at them, even if the sending robot uses a broadcast communication modality. We demonstrate spatially targeted communication using a heterogeneous multirobot system composed of flying robots and ground-based self-assembling robots. Flying robots use their privileged view of the environment to determine and communicate information to groups of ground-based robots on what morphologies to form to carry out upcoming tasks. © 2012 IEEE.SCOPUS: cp.pinfo:eu-repo/semantics/publishe
Cooperation in a Heterogeneous Robot Swarm through Spatially Targeted Communication
No full textSwarm Intelligence: 7th International Conference, ANTS 2010 (Brussels, Belgium, September 8-10, 2010)info:eu-repo/semantics/publishe
ARTAR-Artistic Augmented Reality
No full textAbstractAugmented reality is a technique which adds computer generated virtual objects into the real world scene. ARTAR proposes a method to enhance the experience of paintings or artistic works by adding an extra level of perception through the inclusion of sound, music, and animations. It contains two layers of perception, the physical appearance of the paintings perceived by naked eye and an augmented layer containing animations and sounds which can be perceived by a mobile device. When an artwork is scanned using a predesigned mobile application certain image reference portions get animated along with some music and sound. In this work, a reference area is found in the input video frame using SURF detector and BRISK descriptor and the virtual object is placed in the particular position. Experimental result shows that SURF-BRISK combination provides better result when compared with other detector descriptor combinations in case of ARTAR
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