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© 2023 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes,creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works. The electromagnetic characterization of reaction wheels is crucial to comply with the demanding ac magnetic field cleanliness requirements of space science missions, thus, preventing interference on sensitive onboard instrumentation. Therefore, a complete assessment, including the measurement of the magnetic flux vector at different operational modes and under dynamic conditions, is proposed as a contribution beyond conventional testing methodologies. This article investigates the worst-case magnetic field emissions experimentally, using a test setup based on a multichannel acquisition and multidomain postprocessing system. The focus of the measurement campaign was on the low-frequency range (10 Hz–2 kHz). Moreover, capturing the B-field in the time-domain enabled further analysis, that is, complementary outputs for understanding the electromagnetic performance of the reaction wheel. As a result, we can relate the wheel rotation with the current and the magnetic fields, compute the field orientation, and evaluate in-band interference for the magnetic field. This work was supported in part by European Union’s Horizon 2020 research and innovation programme under Marie Skłodowska-Curie under Grant Agreement 801342 (TecniospringINDUSTRY) and the Government of Catalonia’s Agency for Business Competitiveness (ACCIÓ) and in part by the Spanish “Ministerio de Ciencia e Innovación” under Project PID2019-106120RBC31/AEI/10.13039/501100011033

The metal-based additive manufacturing (MAM) processes have great potential in wide industrial applications, for their capabilities in building dense metal parts with complex geometry and internal characteristics. However, various defects in the MAM process greatly affect the precision, mechanical properties and repeatability of final parts. These defects limit its application as a reliable manufacturing process, especially in the aerospace and medical industries where high quality and reliability are essential. MAM process monitoring provides a technical basis for avoiding and eliminating defects to improve the build quality. Based on of the nature of the MAM build defects, this article conducts a thorough investigation of monitoring methods, and proposes a machine learning (ML) framework for process condition monitoring. According to the structure of ML models, they are divided into shallow ML-based and deep learning-based methods. The state-of-the-art ML monitoring approaches, as well as the advantages and disadvantages of their algorithmic implementations, are discussed. Finally, the prospects of ML based process monitoring researches are summarized and advised.

As an increasing number of asteroids are being discovered, detecting them using limited propulsion resources and time has become an urgent problem in the aerospace field. However, there is no universal fast asteroid sequence selection method that finds the trajectories for multiple low-thrust spacecraft for detecting a large number of asteroids. Furthermore, the calculation efficiency of the traditional trajectory optimization method is low, and it requires a large number of iterations. Therefore, this study combines Monte Carlo tree search (MCTS) with spacecraft trajectory optimization. A fast MCTS pruning algorithm is proposed, which can quickly complete asteroid sequence selection and trajectory generation for multispacecraft exploration of multiple asteroids. By combining the Bezier shape-based (SB) method and MCTS, this study realizes the fast search of the exploration sequence and the efficient optimization of the continuous transfer trajectories. In the simulation example, compared with the traversal algorithm, the MCTS pruning algorithm obtained the global optimal detection sequence of the search tree in a very short time. Under the same conditions, the Bezier SB method obtained the transfer trajectory with a better performance index faster than the finite Fourier series SB method. Performances of the proposed method are illustrated through a complex asteroid multiflyby mission design.

This paper proposes a scheme of space vector optimization for model predictive control (MPC) of dual three-phase permanent magnet synchronous machine (DTP-PMSM), which aims to restrain the current harmonics under the condition of low inductance. The multiphase electric motor possesses the characteristics of quick current variation rate by means of the low inductance. Especially incorporating with MPC schemes, its advantage of quick response shows promising prospects for various applications such as robotics, aerospace and medical devices. However, such a characteristic of low inductance requires shorter control period, which means that the traditional MPC cannot be implemented to suppress the current harmonics since the performance of the power switching devices and the digital controller limits the arbitrary increasing of the control frequency. This paper presents the space-vector-optimized model predictive control (SVO-MPC) for DTP-PMSMs with low inductance by pre-synthesizing space vectors to eliminate harmonics and optimizing the zero vector to deal with quick current response. As a result, the proposed SVO-MPC can remarkably improve the steady and dynamic control performance, while the traditional MPC almost fails at commonly-adopted control frequency. Lastly, simulated and experimental results are both given to verify the feasibility of the proposed SVO-MPC for DTP-PMSMs with quick current response.

Apache Log4j2 is a prevalent logging library for Java-based applications. In December 2021, several critical and high-impact software vulnerabilities, including CVE-2021-44228, were publicly disclosed, enabling remote code execution (RCE) and denial of service (DoS) attacks. To date, these vulnerabilities are considered critical and the consequences of their disclosure far-reaching. The vulnerabilities potentially affect a wide range of internet of things (IoT) devices, embedded devices, critical infrastructure (CI), and cyber-physical systems (CPSs). In this paper, we study the effects and feasibility of exploiting these vulnerabilities in mission-critical aviation and maritime environments using the ACARS, ADS-B, and AIS protocols. We develop a systematic methodology and an experimental setup to study and identify the protocols’ exploitable fields and associated attack payload features. For our experiments, we employ software-defined radios (SDRs), use open-source software, develop novel tools, and develop features to existing software. We evaluate the feasibility of the attacks and demonstrate end-to-end RCE with all three studied protocols. We demonstrate that the aviation and maritime environments are susceptible to the exploitation of the Log4j2 vulnerabilities, and that the attacks are feasible for non-sophisticated attackers. To facilitate further studies related to Log4j2 attacks on aerospace, aviation, and maritime infrastructures, we release relevant artifacts (e.g., software, documentation, and scripts) as open-source, complemented by patches for bugs in open-source software used in this study. peerReviewed

This letter focuses on the detection of subtle human activity, from multipass airborne interferometric synthetic aperture radar (InSAR) images, of such activities causing absolute decorrelation between two acquisitions. These activities can be vehicle track, footprint, grazing, and human construction. The millimetric sensitivity of the interferometric phase makes it valuable for detecting such activities. It can bring a large value to civil and military applications. However, there are always high false alarms in the conventional detection method. To solve this problem, a human activity detection method based on the coherence matrix is approached in this letter. In the final part of this letter, a preliminary validation of the method is provided by processing actual multipass airborne InSAR data stacks acquired by the Aerospace Information Research Institute, Chinese Academy of Sciences. It is noted that the proposed method reaches reliable results in comparison with the ground truth.

This article develops a system dynamics model for innovation ecosystems in the high-tech industry. The model emphasizes the interactions between high-tech enterprises, the government, and universities in the innovation process. In particular, we use two high-tech instruments, the Mars Rock Corer and the Soil Preparation System, in the aerospace innovations developed by Hong Kong Polytechnic University. These instruments are a byproduct of collaborations with the European Space Agency, Russian Space Agency, and China Space Agency. They span decades of space missions to the moon and Mars. Furthermore, we propose a three parities systems dynamics model to study innovation behaviors. This model can be used to study and analyze the stakeholders’ interactions in high-technology-oriented innovation ecosystems. Theoretical, computational, and simulation studies are also conducted to understand and evaluate the evolution of the ecosystem. The results demonstrate the feasibility and effectiveness of this approach, which can be applied in on a large scale and in complex space projects.

In this paper, we propose a new sampled-data controller for stabilization of the attitude dynamics at a desired constant configuration. The design is based on discrete-time interconnection and damping assignment (IDA) passivity-based control (PBC) and the recently proposed Hamiltonian representation of discrete-time nonlinear dynamics. Approximate solutions are provided with simulations illustrating performances.

A hydraulic cylinder is a mechanical actuator that is widely used in different industries such as construction, manufacturing, aerospace and offshore oil and gas. Seal wear in hydraulic cylinders results in hydraulic fluid leakage or contamination of the hydraulic fluid. Untimely failure of a hydraulic cylinder increases the maintenance cost and reduces productivity. Therefore, condition monitoring of the hydraulic cylinder is necessary to understand the current state of equipment. In literature, there have been numerous documented attempts to perform condition monitoring of hydraulic cylinders using different methods, based on fluid properties, pressure, vibration and acoustic emission. However, there have been limited attempts to present a state-of-the-art review of condition monitoring of hydraulic cylinders. This paper presents an overview of the methods used for the condition monitoring of hydraulic cylinders, including the detection of different failure modes using different sensors, the separability of fault conditions using sensor-based features, and the ability to pick up incipient faults by sensor-based features. This information is required for new readers in this area of expertise. This paper summarizes different condition monitoring methods that have been used from its early implementation to very recent dates, aiming at clarifying recent advances and identifying challenges in the research of the condition monitoring of hydraulic cylinders. It is anticipated that the information presented in this review paper will be beneficial for new researchers and provide directions for future research in the area of condition monitoring of hydraulic cylinders.

This article presents a fabrication method for a $C$ -band, low-power, frequency-modulated continuous wave (FMCW) radar front–end technology demonstrator that is fully embedded in a representative aerospace composite structure. This demonstrator uses a structural glass-fiber-reinforced polymer laminate as both the mechanical load-bearing element and the multilayer substrate for the integrated microwave circuitry. The system design and optimization have been described in detail. The electromagnetic simulation of the technology demonstrator was shown to be in excellent agreement with the measurement results. Finally, the FMCW radar front-end was tested as a complete system and shown to yield correct distance-to-target estimations. The demonstrated integration technique will lead to smart skins where electronic circuits and complete systems are embedded in load-bearing composite structures to yield truly multifunctional capabilities.

In advanced technology nodes, SRAM cells, used in the aerospace industry, have become highly susceptible to soft-error. In this brief, a Soft-Error-Aware Read-Decoupled 14T (SAR14T) SRAM cell is proposed for aerospace applications. To assess the performance of the proposed cell, it is compared with other soft-error-aware SRAM cells, like WE-QUATRO, QUCCE12T, RHD12T, RSP14T and RHBD14T. Simulation results show that all the sensitive nodes of SAR14T can reattain their initial states after being impacted by soft-error. Furthermore, the cell is capable of recovering from multi-node upset induced at its internal node-pair. Due to the employment of the read-decoupling technique, SAR14T shows the highest read stability compared to its peers. The proposed cell also proves to be the superior SRAM in terms of write ability and write delay. All these improvements are accomplished at the expense of a slightly longer read delay.

With space and aerial platforms deployed at different altitudes, integrated ground-air-space (IGAS) networks will\ud have multiple vertical layers, hence forming a three-dimensional\ud (3D) structure. These 3D IGAS networks integrating both aerial\ud and space platforms into terrestrial communications constitute a\ud promising architecture for building fully connected global next\ud generation networks (NGNs). This article presents a systematic\ud treatment of 3D networks from the perspective of multi-objective\ud optimization. Given the inherent features of these 3D links,\ud the resultant 3D networks are more complex than conventional\ud terrestrial networks. To design 3D networks accommodating the\ud diverse performance requirements of NGNs, this article provides\ud a multi-objective optimization framework for 3D networks in\ud terms of their diverse performance metrics. We conclude by\ud identifying a range of future research challenges in designing\ud 3D networks and by highlighting a suite of potential solutions.

This article describes the envisioned interactions between information and communication technology (ICT) and the aerospace industries to serve autonomous devices for next-generation aerial parcel delivery networks. The autonomous features of fleet elements of the delivery network are enabled by the increased throughput, improved coverage, and near-user computation capabilities of vertical heterogeneous networks (VHetNets). A high-altitude platform station (HAPS), located around 20 km above the ground level in a quasi-stationary manner, serves as the main enabler of the vision we present. In addition to the sensing potential of the HAPS nodes, the use of communication, computing, and caching capabilities demonstrates the attainability of the ambitious goal of serving a fully autonomous aerial fleet capable of addressing instantaneous user demands and enabling supply chain management interactions with delivery services in low-latency settings.

This article investigates the design of a 250 kW permanent magnet (PM) machine used for aircraft propulsion. The focus is to pursue high specific power (>20 kW/kg), high efficiency (>95%), and low thermal resistance direct-cooling design for the demanding aerospace applications. The proposed key-enabling technology is additively manufactured hollow conductors integrated with heat pipes. Compared to the existing high specific power PM machines for aerospace applications, the proposed design features a much lower speed – 5000 r/min without any torque amplifier, which helps promote the specific power of the overall system. Based on parametric finite-element analysis, tradeoff studies on a variety of winding configurations as well as geometrical parameters have been carried out, highlighting their impact on specific power, winding ac losses, and efficiency. AlSi10Mg coil samples printed by direct metal laser sintering as well as thermal management system have been demonstrated to show the feasibility of the concepts.

Continuum hyper-redundant manipulators (CHRMs) have been widely applied in aerospace, medical or other fields to complete tasks in narrow and multi-obstacles environments with its unique structural advantages. Due to the redundancy, the inverse kinematics of CHRMs is rather complex and the trajectory planning has always been the focal and challenging point in the research of CHRMs. To tackle this issue, the present study proposes an overall configuration planning method of CHRMs based on the improved artificial potential field (APF) method. The method avoids the complicated inverse kinematics and vastly reduces the computational complexity. First, a virtual guiding pipeline (VGP) with no obstacles inside is constructed based on a known target configuration and the minimum safe distance. The movement of the CHRM is restricted to the pipe by the APF method. Then, we propose a method to construct a guided potential field in the VGP to solve the local minimum problem of the traditional artificial potential field method. Further, to address the issue of contradictory forces in the overall configuration planning, the maximum-work planning strategy is proposed. Finally, simulations are conducted and the results demonstrate the high performance of the method in terms of planning efficiency, environmental adaptability.

In aerospace applications, the investigation of the physical properties of the materials used as thermal protection systems (TPSs) is mandatory. One of the most important material properties involved in the prediction and measurement of the aerothermal loads is the material surface emissivity. In fact, to set properly optical devices operating in the infrared region of light, it is necessary to know the material emissivity for the measurement of the temperature at surface. In order to perform such analysis during the development of a test in a hypersonic plasma ground simulator, like the CIRA-PWT SCIROCCO and GHIBLI facilities, the INPP Laboratory developed techniques for the investigation of the spectral emissivity by properly using dual-color pyrometers. Those techniques have been applied during tests carried out in the SCIROCCO and GHIBLI facilities on materials candidate for TPS of re-entry space vehicles. In the present work, those techniques are shown and the kind of results obtained during experiments.

The papers in this special section focus on the use of mechatronics in unmanned systems. During the past few decades, unmanned systems have widely been applied in the environs of aerospace, ground, surface, and underwater. It is expected that unmanned systems will have more pervasive applications in industry, military, agriculture, logistics, etc.,when advanced mechatronic technologies are combined with complex systems engineering. Mechatronic design offers feasible solutions for unmanned systems to operate robustly and efficiently under diverse and difficult environmental conditions, but brings challenges for design, sensing, and control. Facing the growing application demands, this subject has drawn increasing attention in recent years. For this reason, the design, implementation, modeling, control, and optimization of unmanned systems have become urgent issues. This focused section aims to report the latest research results, both theoretical and application-oriented and to emphasize mechatronics in unmanned systems, including mechanism design and optimization of unmanned systems, modeling and control of unmanned systems, bioinspired mechatronics in unmanned systems, applications of mechatronic for unmanned systems, etc. Topics explored in this focused section include, but be not limited to, theoretical foundations for mechatronics in unmanned systems, mechatronics design of the unmanned systems, mechanism design, fabrication and optimization of unmanned systems, modeling, identification, sensing, and control of unmanned systems, mechatronics in unmanned space/aerial/ground/surface/underwater vehicles, bioinspired mechatronics in unmanned systems, and applications of mechatronics for unmanned systems in industry/ military/agriculture/logistics.

Advanced manufacturing technologies have made great progress in the fields of aerospace, resources, and power, and the complex curved surface parts with local rapidly varied geometric feature are increasingly and widely used. On account of the complex geometric feature for this kind of parts, global processing technology cannot meet the requirements of high quality and high-efficiency processing, and the subregional processing method is used. However, the existing methods usually lead to bad machining quality at the boundary and are also prone to form obvious machined trace at the center of machining region in subregional processing. Hence, in this article, a subregional toolpath regeneration method for contour-parallel processing based on the isoscallop method is proposed. First, the initial toolpath generation is finished, which can ensure machining quality at the boundary. Then, establishing the arc length error calculation model for the innermost loop of toolpaths, the arc length error is averaged in the side-step direction and the feeding direction by modifying the cutter contact points. Finally, the toolpath regeneration is realized, which can reduce machined trace at the center of machining region. Experimental results show that with the proposed method, the profile arithmetic average error and the maximum of profile deviation decrease by 32.03% and 53.38%, respectively, at the innermost loop of toolpaths compared with the results of the conventional isoscallop method. For that, the proposed method can improve the machining quality effectively for complex curved surface in subregional contour-parallel processing.

A comprehensive approach is offered for avionics engineering topics and curricula for educational activities that better meet contemporary aerospace industry requirements. These topics include a growing demand for airspace mobility services, the proliferation of unmanned aircraft systems (UAS), and the required enhancements in avionics and air traffic management (ATM) design standards (hardware and software components); targeting the evolving safety, interoperability, and cybersecurity needs of the aeronautical and space sectors. Proposed topics and approaches stem from the Institute of Electrical and Electronics Engineers (IEEE) Aerospace and Electronics Systems Society (AESS) Avionics Systems Panel (ASP) discussions aimed at aligning educational approaches to relevant industry needs and technical advancements in the field of avionics engineering. Suitable curricular development approaches are proposed to address the career life cycle of avionics engineers, including undergraduate and graduate education. Collaborative exchange and discussion, including both industrial and academic perspectives, focus on informing curricular development approaches that bridge the gaps between higher education, industry practice, and public stakeholder needs toward maximizing educational outcomes and preparedness of the avionics engineering workforce to tackle some of the most important challenges and opportunities faced by the aerospace sector.

Modern electrical machines employed in transportation applications are required to provide high performance in terms of power (and torque) density. At the same time, being these applications safety-critical, a significant level of reliability and/or fault tolerance is expected. Among all the factors which can compromise motors reliability, partial discharges (PDs) inception is one of the most crucial, in particular for low voltage, random wound machines. This article presents an extensive experimental investigation on PDs in electrical machines for aerospace applications. Measurements are carried out using both sinusoidal and fast-rising pulses in a representative aerospace environment, emulating the typical ambient conditions encountered throughout a commercial aircraft mission, and beyond (i.e., down to 30 mbar). As a main result of the investigation, it is proved that electrical machines employed for actuating primary flight control surfaces feature a higher risk of PDs inception. Therefore, their insulation system demands an extremely careful design.

Recently, the COVID-19 pandemic has been a painful reminder of the vulnerability of the aerospace industry. It is currently facing challenges with costs, expensive fuels, and carbon emissions. In recovering the industry, regaining its competitiveness, and addressing future climate goals, an unprecedented revolution is needed. The aviation sector is at a crossroads, and several international agencies have put forth radical goals for its future. Sectors that were hardest hit by COVID-19 require particular attention and must be prioritized. © 2020 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.

The pandemic interruption has accelerated many necessary technology changes. Certainly, it was not the root cause, but it was a catalyst. Many topics had been evolving in past years and now create the new normal, such as ecologic behaviors and collaborative working. Many industries, such as automotive and aerospace, faced structural problems for years. And-fortunately in the aftermath-many technologies could readily be applied, such as digital transformation, flexible distance services, e-mobility, biotechnology, and secure collaboration.

This review paper presents new and emerging technologies for structural monitoring of inflatable space structures such as aerospace and space vehicles and habitats. Inflatable structures provide an array of benefits for space operations including low mass and cost, high volume, and versatility. Despite the fact that there has been a fair amount of research on structural monitoring of solid structures in the past, inflatable structures did not receive the attention they deserve until recently. Monitoring an inflatable space vehicle or habitat poses challenges beyond those associated with similar structures on earth. The potential damage caused by micrometeorites and orbital debris (MMOD) requires a rigorous study of the impact to determine the location of impact and, in case of damage, identifying the extent of the damage, and location of the air leak if present. In this review paper, several recent developments in wireless sensing and signal processing that are used for accurate leak detection and localization are presented. Theoretical foundations behind these algorithms and systems, as well as laboratory and field test results (on earth and in space), are presented to paint a complete picture from research and development to flight certification and test.

Hybrid Energy Storage System has been widely applied in aerospace, electric vehicle, and microgrid applications. The advantages are that they include complimentary technologies with both high power and energy capabilities. HESS have the potential to be useful to the bulk power systems, for example to increase the value of energy produced by variable generation resource through enabling participation in ancillary service markets. Actualizing the benefits of HESSs requires optimizing the combined ramping capability of aggregated HESS resources. To provide quality ancillary service, source of HESSs locating at multiple sites of variable generation resource must be optimally sized and cohesively controlled. Optimizing aggregated resources can be formulated as an optimization problem. Successfully solving this problem not only requires using effective solution methods but also depends on accurately and rapidly setting the necessary parameters in the problem formula. This article proposes a novel framework with double-layer structure to solve the optimization problem of aggregating ramping capability. Program developed on the upper layer focuses on solving the optimization of aggregating ramping capability among multiple HESSs and is compatible with most existing optimization algorithms. Program on lower layer of the framework targets at optimizing the local control of a single HESS based on a thorough analytics of HESS operation strategy presented in this article. Result of local optimization is also provided to upper layer program for updating the parameters in formula of optimization problem. Real time hardware-in-the-loop test is conducted to verify the performance of the optimization framework developed. The work presented is expected to provide guidance for implementing this framework in practical operation.

An improved weather-forecast-based link-budget design technique for space-to-Earth links is described. The aim is the stochastic optimization of both transmission symbol rate and received signal-to-noise ratio. The proposed radiometeorological operations prediction (RadioMetOP) model takes into account the forecast uncertainty by a space–time ensemble method exploiting the temporal evolution of the predicted radiometeorological variables over the weather-forecast spatial grid. The unique possibility of testing and validating the RadioMetOP model is presented, thanks to the $Ka$ -band downlink measurements available from the support of the European Space Agency’s antenna tracking network to deep-space Hayabusa-2 (HB2) mission, operated by the Japan Aerospace Exploration Agency. First, the RadioMetOP model accuracy is tested by comparing the signal-to-noise ratio, measured during the transmission periods, with the simulated one, properly scaled to the symbol rate operated by HB2, finding correlation values of 0.9 that confirm the effectiveness of the proposed approach. Second, the $a$ posteriori analysis of the optimization process is accomplished, showing that depending on the considered criteria for the link-budget optimization, the use of the RadioMetOP model would have allowed a transmitted data volume more than doubled and an average signal-to-noise ratio gain between 2.1 and 3.8 dB.

Respecting the requirements of lightweight, small size, low power consumption and especially low cost, commercial off-the-shelf (COTS) analog-to-digital converters (ADCs) are gradually being used to replace specifically designed aerospace -grade ones in space-borne miniature interferometric fiber-optic gyroscopes (IFOGs). However, the total ionizing dose (TID) effect of $\gamma $ -ray radiation in the space environment may cause the damage of COTS ADCs, and lead to performance degradation and even the failure. In order to measure the safety of COTS ADCs in IFOGs under the TID effect, the radiation-induced degradation model and the corresponding reliability model are proposed in this work. First of all, the relationship between the degradation of COTS ADCs and the IFOG’s angular random walk (ARW) is deduced. Then, a radiation accelerated test is designed and performed, with a real-time, dynamic data acquisition method based on the first-input-first-output (FIFO) memories to determine the degradation of COTS ADCs. Finally, a degradation path model is established based on the degradation data, and the reliability of COTS ADCs used for space-borne IFOGs is further obtained by using the Monte Carlo method. An engineering application is introduced to show the effectiveness of the proposed model, and the results show that the reliability of the experimental COTS ADCs makes them usable for the space-borne miniature IFOGs in low-earth orbit (LEO) and geostationary earth orbit (GEO) space missions.

Gas detection plays an important role in many fields, such as atmospheric environment monitoring, biological monitoring, gas leakage monitoring, gas decomposition products detection, and so on. Nowadays, there are many kinds of gas sensors. Compared with normal gas sensors, optical sensors have the advantages of antielectromagnetic interference, high sensitivity, and compact size. Especially in certain extreme conditions, such as in aerospace applications and oil exploration application, optical fiber sensors are more attractive. This article presents a critical review on fiber loop ring-down spectroscopy (FLRDS), which can be used for quantitative detection of concentrations of trace gases. Fiber cavity is the core component of FLRDS system. The principles, loss characteristics, and application ranges of different types of fiber cavities are discussed. This article brings a variety of FLRDS techniques and introduces the basis for each technique, recent developments in methods, and performance limitations in detail. Finally, the existing technical barriers and future prospects of the FLRDS system for gas sensing are presented.

Presents information on the 7th IEEE AESS Virtual Workshop on Metrology for AeroSpace conference.

Power electronics are crucial elements in more-electric aircraft (MEA) applications. Existing hardware is almost exclusively silicon (Si)-based. However, recent advances in semiconductor technology yielded silicon carbide (SiC) components with current ratings suitable for aerospace applications. These devices have much strength that can increase power density and improve performance over Si-based hardware. High switching speeds are characteristic of SiC devices, and there is much concern about their impact on electromagnetic interference (EMI). This may necessitate larger EMI filters to comply with EMI standards, which would decrease power density and negate some of SiC’s benefits. The following research explores the tradeoff between efficiency and EMI. It compares the performance of two high-power three-phase converters: one built from SiC MOSFETs and the other from Si IGBTs. The test setup consists of a 250-kW drive stand capable of sourcing and regeneratively sinking power as well as a 40-kVA aerospace rated machine. Experimental results are obtained at a bus voltage of 270-Vdc with power levels exceeding 1.5 p.u. The findings demonstrate comparable EMI performance for Si and SiC under MIL-STD-461 with the SiC converter achieving higher efficiency.

Since the year 2000, several studies on bounding end-to-end delays in switched Ethernet topologies required in the design of distributed processing systems on board of aerospace vehicles were made public. These studies presented various approaches for dealing with the non-deterministic behavior of non-synchronized network traffic while striving to avoid overestimation. One of them described an effect observed in frame-based network transmissions and named it “serialization”. This effect is used in this paper with the objective of constructing a new low-complexity method for estimating the worst case delay experienced by a frame crossing a switched Ethernet. This method results from the combination of two new propositions which inherit concepts originally formulated by schedulability analysis methods for multitask processing systems. Its implementation is shown on a case study using a step-by-step procedure and the results obtained are favorably compared with one previously published work.

This article focuses on the electrical performance of a new Ethernet contact with four differential pairs called “Octomax.” The eight pins of the contact are inserted in a section of 17 mm2. Such a high-speed interconnect solution is specially developed to operate at 10 Gbits/s in harsh environments for military and aerospace applications. The theoretical study up to 1 GHz enables quantifying the crosstalk between two differential pairs [near-end crosstalk (NEXT)], the return loss (RL), and the insertion loss (IL). An optimization using a combined 2-D–3-D electromagnetic approach, which is simultaneously validated by measurement in frequency and time domains, leads to a final prototype that meets the category 6A Ethernet standard for a predictable data rate of 10 Gbits/s.

With complementary metal oxide semiconductor (CMOS) technology scaling down, radiation induced multiple-node upsets (MNUs) that include double-node-upsets and triple-node upsets (TNUs) are becoming more and more an issue in storage cells used for applications constrained by their environment, such as aerospace applications confronted to radiations. This article presents a novel triple-modular redundancy without voter based high-impedance state (HIS) insensitive and MNU-tolerant latch design, namely TMHIMNT, to ensure both high reliability and low cost. The TMHIMNT latch mainly comprises triple clock-gating (CG) based dual-interlocked-storage-cells (DICEs) and four inverters. Through three internal inverters, the values stored in DICEs converge to a common node feeding an output-level inverter, enabling the TMHIMNT latch to tolerate any possible MNU. Simulation results demonstrate the MNU tolerance of the proposed TMHIMNT latch. Due to the disuse of C-elements, the proposed TMHIMNT latch is insensitive to the HIS, making the latch more reliable for aerospace applications. Moreover, compared with the state-of-the-art TNU hardened latch, due to the use of a high-speed path, CG technologies, and fewer transistors, the proposed TMHIMNT latch can achieve 98% delay, 17% power, and 29% area reductions, respectively.

ManitobaSat-1 is a 3U CubeSat program that is determined to advance the edges of space technology by performing things differently from traditional design strategies (see Fig.1). This will enhance access to space through novel technology development and verification and enable smaller companies to benefit from satellite services. ManitobaSat-1 is being developed at the University of Manitoba by the Space Technologies and Advanced Research Laboratory (STARLab) in collaboration with the Center for Terrestrial and Planetary Exploration at the University of Winnipeg, York University, the Interlake School Division, and Magellan Aerospace, our industrial partner.

In recent years additive manufacturing technologies have become widely popular. For complex functional components or low volume production of workpieces, laser powder bed fusion can be used. High safety requirements, e.g. in the aerospace sector, demand extensive quality control. Therefore, offline non-destructive testing methods like computed tomography are used after manufacturing. Recently, for enhanced profitability and practicality online non-destructive testing methods, like optical tomography have been developed. This paper discusses the applicability of eddy current testing with magnetoresistive sensors for laser powder bed fusion parts. For this purpose, high spatial resolution giant magnetoresistance arrays are utilized for testing in combination with a single wire excitation coil. A heterodyne principle minimizes metrology efforts. This principle is compared to conventional signal processing in an eddy current testing setup using an aluminum test sample with artificial surface defects. To evaluate the influence of the powder used in the manufacturing process on eddy current testing and vice versa, a laser powder bed fusion mock-up made from stainless steel powder (316L) is used with artificial surface defects down to $100~\mu \text{m}$ . This laser powder bed fusion specimen was then examined using eddy current testing and the underlying principles.

Additive manufacturing (AM) has been undergoing dynamic development in recent years. The latest evolution of AM has been recognised as a key enabling technology in a wide range of applications, some of which include medical, aerospace and automotive industries. The use of AM opens new avenues for design solutions, otherwise challenging or impossible to realise when using more conventional techniques for manufacture. No- or low-material waste and high-flexibility are some of the attributes of modern AM. This expanded paper aims to provide an up to date overview of the existing examples of employing AM in construction of electrical machines. The paper reviews research and development work related to all integral components of an electrical machine assembly. These include active parts like coils/windings, electrical insulation, stator/rotor magnetic core packs, permanent magnets (PMs). The machine structural/mechanical and thermal management components are also discussed in the paper. Further to these, the authors make some comments/forecasts on how the AM could improve performance and manufacturability of the future electrical machines.

This letter presents a novel configuration of a high- $Q$ bandwidth (BW) reconfigurable waveguide (WG) filter tuned with only two tuning elements regardless of the filter order. The filter is realized in rectangular WG technology and is capable to tune the BW without deviating the center frequency. Furthermore, the configuration is scalable to higher order filters without the need for additional tuning mechanisms. For the proof of concept, a four-pole prototype filter is designed, fabricated, and tested at the Ku -band. The measured BW tunability of the filter is nearly 35% from 225 to 320 MHz. The center frequency remains unaltered at 13.375 GHz over the BW range.

In recent years, several advances in artificial intelligence such as deep learning, computer vision, automatic driving, cognitive computing, and robotics, have laid the technological foundation for the large-scale application of Smart-AMPs in complex environments. Potential solutions have appeared for smart transportation, aerospace exploration, smart logistics and smart cities. This article summarizes all kinds of autonomous moving platforms, proposes a definition of Smart- AMPs, and investigates taxonomy, technologies, applications, open issues and key challenges for Smart-AMPs. This article is suitable as a pedagogical overview of Smart-AMPs.

Computation of matrix exponentials is commonly encountered in aerospace and electronic systems. Computing matrix exponentials via a reverse summation of the truncated Taylor series is discussed.

Traditional offline programming or teach pendant-based methods limit the collaboration capabilities of users and robots to cope with complex and changing industrial tasks. To address efficient robot manipulation in high-mix and low-volume tasks, especially for skillful tasks involving both trajectory and force control requirements, fast robot teaching and skill transferability are critical. Compared to manually dragging a heavy robot, or programming a trajectory by complex calculations, we believe that robots can efficiently learn skills from direct teaching through telemanipulation, and improve the skills based on optimization with sensory feedback. In aerospace engine, maintenance, repair, and operations, the surfaces of aerospace components are required to be masked by tapes. We propose a fast and intuitive telemanipulation-based method to teach a robot these masking skills and compare the performance of the proposed method with teach pendant–based methods among several users. This study aims to prove the efficiency and intuitiveness of the telemanipulation-based method proposed herein for enabling a robot to learn skillful and complex manipulation tasks.

As mentioned in a recent editorial in this magazine [1], distributed generation (renewables), automotive and, in general, transport and industrial utilization are fast changing the structure of electrical assets as well as the typologies and design of electrical apparatus. This is due mostly to the more widespread use of renewable generation and the electrification of transport, including power electronic converters and inverters, which can provide higher voltage, lower losses and make the asset more efficient and power dense. In the long run, medium voltage (MV) transformers will tend to disappear and perhaps high voltage (HV) transformers may be endangered. The future typical industrial, transport and, likely, T&D assets will be made by hybrid networks where power will be delivered in AC or DC, depending on convenience, and most of the loads (rotating machines) will be controlled by power electronics.

This letter presents a solution for the state estimation and control problems for a class of unconventional vertical takeoff and landing (VTOL) UAVs operating in forward-flight conditions. A tightly-coupled state estimation approach is used to estimate the aircraft navigation states, sensor biases, and the wind velocity. State estimation is done within a matrix Lie group framework using the Invariant Extended Kalman Filter (IEKF), which offers several advantages compared to standard multiplicative EKFs traditionally used in aerospace and robotics problems. An $SO(3)$ -based attitude controller is employed, leading to a single attitude control law without a separate sideslip control loop. A control allocator is used to determine how to use multiple, possibly redundant, actuators to produce the desired control moments. The wind velocity estimates are used in the attitude controller and the control allocator to improve performance. A numerical example is considered using a sample VTOL tailsitter-type UAV with four control surfaces. Monte-Carlo simulations demonstrate robustness of the proposed control and estimation scheme to various initial conditions, noise levels, and flight trajectories.

A two-player differential game is considered where a spy infiltrates the region of interest and a defender pursues and tries to capture the spy before it leaves such region. This letter provides the complete solution of this game by characterizing the Barrier surface which separates the state space into the regions of win of the defender and the spy. In each region the optimal strategies that guarantee the prescribed outcome are provided. This is in contrast to recent results addressing the same problem where the proposed strategies do not guarantee capture of the spy by the defender when initially this outcome was prescribed by the game of kind solution.

In harsh radiation environments, nanoscale CMOS latches have become more and more vulnerable to triple-node upsets (TNUs). This paper first proposes a latch design that can self-recover from any possible TNU for aerospace applications in the 16-nm CMOS technology. The proposed latch is mainly constructed from seven mutually feeding-back soft-error-interceptive modules (SIMs), any of which consists of two three-input C-elements and one two-input C-element. Due to the mutual feedback mechanism of SIMs and the dual-level soft-error interception of each SIM, the latch can self-recover from any possible TNU. Simulation results demonstrate the TNU self-recoverability from any key TNU for the proposed latch using redundant silicon area. Furthermore, using a high-speed path, the proposed latch saves about 95.45% transmission delay and 86.97% delay-power-area product, compared with the state-of-the-art TNU-tolerant latch that cannot provide complete TNU self-recoverability at all.

Power module packaging technologies have been experiencing extensive changes as the novel silicon carbide (SiC) power devices with superior performance become commercially available. This article presents an overview of power module packaging technologies in this transition, with an emphasis on the challenges that current standard packaging face, requirements that future power module packaging needs to fulfill, and recent advances on packaging technologies. The standard power module structure, which is a widely used current practice to package SiC devices, is reviewed, and the reasons why novel packaging technologies should be developed are described in this article. The packaging challenges associated with high-speed switching, thermal management, high-temperature operation, and high-voltage isolation are explained in detail. Recent advances on technologies, which try to address the limitations of standard packaging, both in packaging elements and package structure are summarized. The trend toward novel soft-switching power converters gave rise to problems regarding package designs of unconventional module configuration. Potential applications areas, such as aerospace applications, introduce low-temperature challenges to SiC packaging. Key issues in these emerging areas are highlighted.

For electronic packaging engineers in the high-reliability sectors, such as aerospace, defense, oil & gas, etc., the use of commercial off-the-shelf components offers significant advantages due to their high availability, fast delivery time, and low cost. However, these components pose significant reliability challenges due to the risks associated with tin whisker formation and uncertainty on the long-term reliability of lead-free solders. For addressing these risks, the hot solder dip process is used to refinish the package by replacing lead-free solder finishes with lead-based finishes to meet the stringent packaging and assembly requirements for these sectors, which are exempt from restriction of hazardous substances (RoHS) legislation. But the hot solder dip process is an extra process that exposes the package to an additional thermal load, which will result in thermomechanical stresses that need to be properly understood and controlled. For addressing this challenge, a multidisciplinary methodology combining thermomechanical models with “dip-to-destroy” experiments and scanning acoustic microscopy has been developed to identify the risk of package material delamination for a number of package designs. Results show that the developed models can predict delamination risks for a range of imposed thermal gradients. Electronic package designs with a direct heat path from dipped terminations to the internals of the package show a higher risk of overstress-induced delamination, and this failure is generally driven by the high-temperature excursion above the glass transition point of the molding compound. The novelty and significance of these findings is that the derived methodology can be used by electronic packaging designers to optimize the thermal parameters of the hot-solder-dip process so that subsequent refinished packages can meet the stringent high-reliability requirements for these sectors.

EQUULEUS (EQUilibriUm Lunar-Earth point 6U Spacecraft) will be the world's smallest spacecraft to explore the Earth-Moon Lagrange point. It is being jointly developed by JAXA (Japan Aerospace Exploration Agency) and the University of Tokyo, and will be launched by NASA's Space Launch System Exploration Mission-1. The spacecraft will fly to a libration orbit around the Earth-Moon L2 point (EML2) and will demonstrate low-energy trajectory-control techniques within the Sun-Earth-Moon region for the first time by a nano-class spacecraft. EQUULEUS also carries three scientific observation missions: imaging of Earth's plasmasphere by extreme ultraviolet wavelength, lunar impact flash observation on the far side of the moon, and micrometeoroid flux measurements in the cis-lunar region. While all these missions have their own scientific objectives, they will also contribute to future human activity and/or infrastructure development in the cis-lunar region. Most parts of the spacecraft system use commercial off-the-shelf components, or are designed based on the experiences of various past space missions, with the exception of the newly developed water resistojet propulsion system. EQUULEUS uses X-band frequency for deep space telecommunication. Japanese deep space antennas (64-m and 34-m) will be nominally used for spacecraft operation, and support from the deep space network of JPL (Jet Propulsion Laboratory) is also being planned, especially for the initial phase of operation. The spacecraft will fly to EML2 in less than one year, and will remain there for scientific observations until shortly before the depletion of the onboard propellant, when the spacecraft will leave the orbit for space-debris compliance.

This letter utilizes the holographic principal to design two metasurface antennas with an equivalent electromagnetic performance. The first antenna is designed with a continuous metasurface impedance variation and serves as the baseline antenna (comparable to similar antennas in the literature). The second antenna is designed using two discrete metasurface impedance values realized with two distinct unit cell geometries. Both holographic antennas are shown to exhibit the equivalent electromagnetic performance. However, the latter design (requiring only two discrete impedance values) simplifies the holographic pattern manufacture, and therefore suggests a new avenue to realize “switchable” metasurface antennas capable of beam steering. The “continuous” and “discrete” antenna designs presented in this letter are fabricated using a unique manufacturing approach to realize a structurally integrated antenna in a representative aerospace glass fiber reinforced composite laminate.

Active flow control by means of plasma actuators has potential advantages over conventional strategies, e.g., mechanical or hydraulic components may be replaced by lightweight, compact, fast response plasma actuators. In this paper, several designs of dielectric barrier discharge (DBD) plasma actuators are presented for aerospace applications and the focus is on the associated feedback control implementation. The interdisciplinary nature of aerodynamic feedback control with plasma, however, makes direct experimental demonstrating an outstanding challenge. Here, we propose a realistic experimental control implementation afforded by commercial off-the-shelf electric products and the major achievement is the detailed instruction (in both electricity and aerodynamics) and the successful demonstration of the closed-loop design in controlling the dominant modes from a cylinder flow setup. The essence of our approach is to drive DBD plasma actuations by a downstream sensor and excite aerodynamic velocity perturbations, which are further amplified on the shear flow from the cylinder, leading to airflow structures, such as vortex roll-up and randomization, which are measured by the downstream sensor to complete the whole loop. We benchmark our control approach by comparing to the predicted dominant frequencies of the controlled flow system, which can be achieved by the Barkhausen stability criterion after establishing the corresponding transfer function of the whole flow control system. Overall, this paper shall assist a host of new applications in aerospace applications in the near future.