Subsystem Design Research Articles

Initial Design for Next-Generation BeiDou Integrity Subsystem: Space–Ground Integrated Integrity Monitoring

It is essential to provide high-integrity navigation information for safety-critical applications. Global navigation satellite systems (GNSSs) play an important role in these applications because they can provide global, high-accuracy, all-weather navigation services. Therefore, it has been a hot topic to improve GNSS integrity performance. This paper focuses on an initial proposal of the next-generation BeiDou Navigation Satellite System (BDS) integrity subsystem, with the aim of providing high-quality and global integrity services for the BDS. This paper first reviews the current status of the third-generation BDS integrity service. Following this, this paper proposes a space–ground integrated integrity monitoring design for the BDS that integrates the traditional ground-based integrity monitoring method, the advanced satellite autonomous integrity monitoring (A-SAIM) method, and the augmentation from low-earth-orbit (LEO) satellites. Specifically, this work offers an initial design of the A-SAIM method, which considers both single-satellite autonomous integrity monitoring and multi-satellite joint integrity monitoring. In addition, this work describes two different ways to augment BDS integrity with LEO satellites, i.e., (a) LEO satellites act as space monitoring stations and (b) LEO satellites act as navigation satellites. Simulations are carried out to validate the proposed design using CAT-I operation in civil aviation as an example. Simulation results indicate the effectiveness of the proposed design. In addition, simulation results suggest that if the fault probability of LEO satellites is worse than 1 × 10−4, LEO satellites can contribute more to BDS integrity performance improvement by acting as space monitoring stations; otherwise, it would be better to employ LEO satellites to broadcast navigation signals. The results also suggest that after taking LEO satellites into account, the global coverage of CAT-I can be potentially improved from 67% to 99%. This work is beneficial to the design of the next-generation BDS integrity subsystem.

Enhancing collaborative PHM of complex equipment: A MBSE approach for PEMFC health management systems

Model-Based Systems Engineering (MBSE) is acknowledged as an anticipatory design methodology. In addressing the operational and maintenance challenges of complex equipment, particularly those capable of self-healing, a Prognostics and Health Management for Digital Twin (PHMDT) framework has been developed in this research. This framework, rooted in MBSE principles, targets digital twins and encompasses four key subsystems: Virtual-Real Mapping, Prediction, Visualization, and Strategy Development & Evaluation. These subsystems facilitate the seamless transition from stakeholder requirements to subsystem analysis and design. Illustrated within the MagicGrid framework, practical implementation scenarios within the PEMFC system are presented. Each proton exchange membrane fuel cell (PEMFC) subsystem is meticulously crafted, leveraging monitoring matrices, refined characterization equations, bespoke state prediction models, and self-healing recovery strategy formulation. Through comprehensive visualization and integration, a robust PHM system is realized, affirming the efficacy and applicability of the PHMDT framework. The aim of this study is to propose a framework that is more suitable for collaborative PHM of complex equipment and to explore in detail the specific implementation structure of each subsystem in the health management of PEMFC.

Research of Options for Constructing Information Management Systems Based on Network Models of Queuing Systems

The use of information management systems (IMSs) for the management of technical facilities is currently one of the directions for further improvement and increase in the effectiveness of the use of technical facilities in solving their target tasks. The existing modern IMSs are a set of hardware and software tools designed for collecting, processing and storing information and management. In the presence of a large amount of information and contradictory factors affecting the quality of management, making informed and timely decisions in the management process is impossible without the use of IMSs. The IMSs currently being developed are, for the most part, specialized systems and are designed to solve specific tasks. In this regard, the development and design of IMSs should be carried out taking into account the relationship with the target indicators and features of the management facilities, the results of a comprehensive analysis of information about the IMS elements in the process of functioning, and structural and algorithmic parameters that affect performance indicators. The use of mathematical models for the study of options for the construction of an IMS is the basis for the design and development of devices and subsystems of an IMS. The IMS models currently being developed make it possible to conduct research for single-stage management processes with the presence of similar service facilities in the system. At the same time, modern technical facilities and control systems are complex complexes with cyclically repeating control processes of various types of means. As a rule, such complexes have a set of parallel operating devices (control channels) that provide control of different types of objects at various stages of information processing. In this case, the structure of the IMS must be represented as a multiphase multichannel technical system in which the process of simultaneous management of several objects of various types takes place. In this regard, the purpose of the article is to develop a mathematical model of an IMS with two phases of management and the presence of an arbitrary number of serviced different types of management facilities. The basis of the model is a multiphase CFR network model with a limited waiting time for an application in the service queue. The study on the model allows choosing an option for building an IMS, in particular, choosing the optimal number of control channels for various types of objects according to the criterion of optimality and restrictions on the cost and time of management. An algorithm for selecting an option for building an IMS has been developed, and an example of calculating the number of control channels for managing three types of objects is given.

Four-stage cascaded adaptive sliding mode control for automatic carrier landing with airwake disturbances and uncertainties

ObjectiveThis paper addresses the carrier landing affected by airwake, parametric uncertainties, and carrier deck motion, its main target being the design of a novel sliding mode based automatic carrier landing system to obtain accurate tracking of the reference trajectory, robustness in terms of disturbances and uncertainties, as well as excellent touchdown accuracy. ApproachFor an aircraft nonlinear dynamics, written under a four-stage cascaded strict feedback form, the design of the novel landing control architecture involves the design of a guidance subsystem, robust sliding mode controllers (for the control of the heading angle, attitude angles, and angular rates), an approach power compensation system, adaptive control laws suppressing the uncertainties and disturbances, a Kalman filter for deck motion prediction, a block computing the reference trajectory, a tracking differentiator block for deck motion compensation, and first-order command filters. Main resultsThe software validation process proves the effectiveness of the sliding mode based control scheme and the suppression of the uncertainties and disturbances. Also, the comparison between the performances of the sliding mode control based carrier landing system and the ones associated to other automatic carrier landing systems shows the superiority of the sliding mode based control scheme, as well as its better touchdown accuracy and landing success rate. SignificanceThis study innovatively transforms the general carrier landing problem into a time-varying tracking control problem for cascaded strict feedback dynamics with disturbances and uncertainties. The new designed automatic carrier landing system is the first control architecture in the literature employing the sliding mode control augmented by adaptive control laws for carrier landing, subjected to airwake, deck motion, and uncertainties.

Thrust Model and Trajectory Design of an Interplanetary CubeSat with a Hybrid Propulsion System

This paper analyzes the performance of an interplanetary CubeSat equipped with a hybrid propulsion system (HPS), which combines two different types of thrusters in the same deep space vehicle, in a heliocentric transfer between two assigned (Keplerian) orbits. More precisely, the propulsion system of the CubeSat considered in this work consists of a combination of a (low-performance) photonic solar sail and a more conventional solar electric thruster. In particular, the characteristics of the solar electric thruster are modeled using a recent mathematical approach that describes the performance of the miniaturized engine that will be installed on board the proposed ESA’s M-ARGO CubeSat. The latter will hopefully be the first interplanetary CubeSat to complete a heliocentric transfer towards a near-Earth asteroid using its own propulsion system. In order to simplify the design of the CubeSat attitude control subsystem, we assume that the orientation of the photonic solar sail is kept Sun-facing, i.e., the sail reference plane is perpendicular to the Sun-CubeSat line. That specific condition can be obtained, passively, by using an appropriate design of the shape of the sail reflective surface. The performance of an HPS-based CubeSat is analyzed by optimizing the transfer trajectory in a three-dimensional heliocentric transfer between two closed orbits of given characteristics. In particular, the CubeSat transfer towards the near-Earth asteroid 99942 Apophis is studied in detail.

Adaptive robust disturbance rejection backstepping control of a novel friction electro-hydraulic load simulator

This paper introduces a novel frictional electro-hydraulic load simulator that avoids the problem of force-motion coupling disturbances in traditional electro-hydraulic load simulators. An adaptive robust disturbance rejection backstepping control (ARDRBC) is proposed to address the challenges posed by parameter uncertainty, external disturbances, and unmodeled behavior, thereby enhancing the system’s tracking capability. A new adaptive rule has been designed to address the uncertainty of mechanical subsystems through virtual control adjustments. A sliding mode control scheme based on immersion and invariance has been integrated into the practical control design of hydraulic subsystem to address the neglected dynamics. The stability of the entire system was analyzed using the Lyapunov stability. Comparative experiments were conducted to confirm the practicality and robustness of the proposed method.

Monte Carlo analysis of a 400N electric pump-fed engine powered by green propellants: Key trends towards an optimal subsystem design

This paper presents a Monte Carlo analysis for electric pump-fed systems. By leveraging the tool, it is possible to determine the optimal values of the main parameters involved in the design, operation, and selection of the pressurization system, enabling an agile system design. The study is conducted for a 400 N electric pump-fed engine powered by green propellants. This process aims at identifying the optimal operational conditions towards wet mass minimization and, eventually, assess whether a system featuring green propellants and electric pump feeding can represent an environmentally friendly alternative to conventional pressure-fed systems powered by MMH and NTO, known for their high toxicity and operational costs. The results obtained confirm similar performance to the state of the art, both in wet mass and delta-v capabilities, these last ones analyzed for different mission profiles involving orbit raising and RAAN phasing. Finally, based on the results obtained, the paper highlights the key trends towards an optimum design of electric pump-fed systems.

The Solar EruptioN Integral Field Spectrograph

The Solar eruptioN Integral Field Spectrograph (SNIFS) is a solar-gazing spectrograph scheduled to fly in the summer of 2025 on a NASA sounding rocket. Its goal is to view the solar chromosphere and transition region at a high cadence (1 s) both spatially (0.5″\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$0.5''$\\end{document}) and spectrally (33 mÅ) viewing wavelengths around Lyman alpha (1216 Å), Si iii (1206 Å), and O v (1218 Å) to observe spicules, nanoflares, and possibly a solar flare. This time cadence will provide yet-unobserved detail about fast-changing features of the Sun. The instrument is comprised of a Gregorian-style reflecting telescope combined with a spectrograph via a specialized mirrorlet array that focuses the light from each spatial location in the image so that it may be spectrally dispersed without overlap from neighboring locations. This paper discusses the driving science, detailed instrument and subsystem design, and preintegration testing of the SNIFS instrument.

Design of Rejection Subsystem for Abnormal Workpiece Condition Modular Production System at Distribution Station

Design of Rejection Subsystem for Abnormal Workpiece Condition Modular Production System at Distribution Station

Analysis of the integrated pattern of hoverable flapping wing micro-air vehicle

Flying creatures, such as insects and hummingbirds, display superior flight capabilities that have inspired the development of Flapping-Wing Micro Air Vehicles (FWMAVs). Although these vehicles have achieved certain milestones, integrating subsystems under stringent size, weight, and power (SWaP) constraints poses significant energy and weight management challenges. These vehicles' common patterns and critical differences still need to be clearly understood, indicating that their integrated patterns still need to be defined.To determine the integrated pattern of these aircraft, this study began with analyzing existing data on hover-capable bionic aircrafts. It then formulated a set of indices through the permutation and combination of subsystem parameters. Key indices were identified by examining the universality and specificity of system indices through case studies of aircraft, which helped establish the integrated pattern of FWMAVs.The study revealed certain commonalities in these aircraft; for example, the actuation system, comprising the drive, transmission, and manipulation systems, accounts for 51.72 % of the take-off weight. Combining the transmission system and structure, the airframe system represents 27.62 % of the take-off weight. The battery system accounts for about 20.18 %, while the electronic system usually constitutes 12.78 % of the aircraft's take-off weight. Additionally, significant variability was observed among aircrafts in parameters such as CD_5 and CD_7, which represent the distribution of control functions, and CS_4, which tests the integration of the structure with the transmission system. This paper constructs an integrated pattern for such aircraft based on these findings.The integrated pattern derived from this work provides a practical range of parameter values for subsystems during the initial design phase of these aircraft. This is crucial for enhancing the iterative convergence speed in engineering, facilitating the parallel development and design of subsystems, and validating the practicality of numerical optimization results from optimization algorithms. Ultimately, this contributes to advancing future designs and developments of hover-capable bio-inspired flying aircraft.

Outcomes and Perspectives from the 4th ESA ModelBased Space Systems and Software Engineering Workshop (MBSE2023) on reducing the gap between model‐based systems engineering and domain‐specific approaches

AbstractIn the context of its initiative to promote the adoption of model‐based approaches in the development of present and upcoming missions, the European Space Agency (ESA) organised this year its annual workshop on Model‐Based Space Systems and Software Engineering (MBSE2023) at its European Space Research and Technology Centre (ESTEC) premises. The aim of this year's workshop was to investigate how the model‐based systems engineering community could contribute to bridging the gap with domain‐specific model‐based approaches used in subsystem design. The World Café Method was used to facilitate the group discussions, the outcomes of which are summarized and presented in this paper.

Electrical design of the flexible imaging diffraction diagnostic for laser experiments (FIDDLE) at the National Ignition Facility (NIF)-Requirements, design, and performance.

The Flexible Imaging Diffraction Diagnostic for Laser Experiments (FIDDLE) is a newly developed diagnostic for imaging time resolved diffraction in experiments at the National Ignition Facility (NIF). It builds on the successes of its predecessor, the Gated Diffraction Development Diagnostic (G3D). The FIDDLE was designed to support eight Daedalus version 2 sensors (six more hCMOS sensors than any other hCMOS-based diagnostic in NIF to date) and an integrated streak camera. We will review the electrical requirements, design, and performance of the electrical subsystems that were created to support this large number of cameras in the FIDDLE. The analysis of the data that the FIDDLE is intended to collect relies heavily on the accurate and well-understood timing of each sensor. We report camera-to-camera timing jitter of less than 100ps rms and sensor integration times of 2.2ns FWHM in 2-2 timing mode. Additionally, diffraction experiments on the NIF produce electric fields (EMI) on the order of 1 kV/m, which have been observed to negatively impact the performance of some electrical components of the FIDDLE. We report on the results of testing hCMOS camera electronics in a similar EMI environment generated in an offline lab. We also summarize the use of a novel approach to using a vector network analyzer as an EMI leak detector to understand and reduce the negative impacts of EMI on the FIDDLE.

A study on multi-channel active sound profiling algorithm for hybrid control of broadband and narrowband noise inside vehicles

The vehicle interior noise consists of both broadband road noise and narrowband engine order noise. Currently, the road noise control (RNC) system and engine noise control (EOC) system operate independently in engineering applications. This paper introduces a novel multi-channel hybrid broadband and narrowband active noise control (HBNANC) algorithm, designed to simultaneously attenuate road noise and engine order noise inside vehicles. On this basis, by integrating an error signal design (ESD) subsystem and a sinusoidal error separation (SES) subsystem, a multi-channel hybrid broadband and narrowband active sound profiling (HBNASP) algorithm is further proposed, enabling specific attenuation or amplification of individual narrowband components to meet subjective acoustic comfort requirements. The paper validates the algorithms’ effectiveness and robustness through simulations, and real vehicle experimental measurements under various conditions. The research offers a comprehensive approach to enhancing the auditory experience inside vehicles, contributing to the advancement of active noise control technology.

Similitude laws for dynamic response of beam-plate coupled structure

The beam-plate coupled structure is a typical structure in spacecraft solar wings, and the prediction of its mechanical environment is crucial for overall design, structure and mechanism subsystem design. However, it is usually difficult to perform ground simulation tests on spacecraft solar wings with full-size structure. Therefore, a scaled model is established based on similarity theory to forecast the dynamic response of the full-size structure. In this article, finite element (FE) and hybrid finite element-statistical energy analysis (FE-SEA) models of the beam-plate coupled structure are established according to the band division principle. Finite element model allows for detailed analysis of structural behaviour, while hybrid models incorporate statistical energy analysis to account for high-frequency dynamics. By integrating these approaches, a comprehensive understanding of the coupled structure’s response can be achieved, facilitating efficient design and optimisation processes. The scaling laws of the dynamic response are obtained by combining the dimensional analysis and equation analysis methods, respectively. The scaled models are designed for verification, and the natural characteristics and vibration responses predicted by the scaled models are basically consistent with those of the prototype. The findings indicate that the prediction accuracy derived from the FE-SEA model is higher, which provides a novel approach for the dynamic similarity of complicated structures such as the solar wings of spacecraft.

Design and Performance Evaluation of the Energy Subsystem of a Hybrid Light and Wave Energy Harvester

Design and Performance Evaluation of the Energy Subsystem of a Hybrid Light and Wave Energy Harvester

Design of clean energy based microplastic collection device

Abstract Microplastics are plastic particles with a particle size of less than 5 mm formed after the degradation of plastic by crushing. Microplastics are chemically stable and difficult to degrade, and they are also enriched with chemical poisons, microorganisms, and pathogenic bacteria[1]. Some microplastics migrate with ocean currents in the ocean, affecting the global distribution of pollution and causing great harm to the stability of marine ecosystems and the marine environment. There are a large number of microplastics in the ocean, and the number is increasing[2][3]. In order to realize the microplastic collection function, a microplastic collection device was designed to reduce operational requirements and costs while realizing microplastic salvage. The overall scheme of the system includes the design of subsystems consisting of a solar power generator, a collection mechanism, a filtration device, a buoyancy device, a lighthouse, an anchor device, and so on. According to the actual needs of the microplastic collection, the mechanical structure and dimensions of each subsystem were designed, the 3D modeling of the overall system was completed using SolidWorks, and a physical model of the microplastic collection device was produced for experimental testing.

Design and analysis of an adaptive radiation resilient RRAM subsystem for processing systems in satellites

Among the numerous benefits that novel RRAM devices offer over conventional memory technologies is an inherent resilience to the effects of radiation. Hence, they appear suitable for use as a memory subsystem in a computer architecture for satellites. In addition to memory devices resistant to radiation, the concept of applying protective measures dynamically promises a system with low susceptibility to errors during radiation events, while also ensuring efficient performance in the absence of radiation events. This paper presents the first RRAM-based memory subsystem for satellites with a dynamic response to radiation events. We integrate this subsystem into a computing platform that employs the same dynamic principles for its processing system and implements modules for timely detection and even prediction of radiation events. To determine which protection mechanism is optimal, we examine various approaches and simulate the probability of errors in memory. Additionally, we are studying the impact on the overall system by investigating different software algorithms and their radiation robustness requirements using a fault injection simulation. Finally, we propose a potential implementation of the dynamic RRAM-based memory subsystem that includes different levels of protection and can be used for real applications in satellites.

INTELLIGENCE ANALYTICAL SUBSYSTEM OF CORPORATE MANAGEMENT (ON THE EXAMPLE OF AN OIL & GAS COMPANY)

The changes that have taken place in the Ukrainian economy in recent years due to the consistent impact of global macroeconomic, epidemiological and military factors of the current deep crisis - actualized for enterprises and corporations a complex adaptive reorganization of their analytical subsystem of their management [1, 2].
 In addition, in order to be consistently effective in today's global business environment (liberalization of markets, their globalization, increased competition, decreasing consumer loyalty, constant variation in oil and gas prices, etc.), oil and gas companies must have an innovative data and knowledge environment that allows seamless and effective joint leveraging knowledge inside the corporation and across the value chain [3]. The application of knowledge-based decision support systems as an important tool of innovative management policy enables effective and sustainable management of a complex of integrated processes of an oil and gas production company (mitigating the impact of crisis factors) [4].
 The scientific and practical results presented in the article regarding the methodology and design of innovative analytical subsystem of the corporation management information systems should be taken into account when reengineering corporate information systems not only in the oil and gas industry in Ukraine [5-6]. 
 Moreover, the obtained results are relevant and applicable not only for local companies, but also for international corporations on emerging markets in the context of global and regional macroeconomic and edipemical crisis phenomena.

Non-Linear Simulation by Harmonic Balance Techniques of Load Modulated Power Amplifier Driven by Random Modulated Signals

The simulation of the steady state and the non-linear stability of a load modulated power amplifier (LMPA) driven by a random modulated generator, fully performed in the frequency domain by harmonic balance (HB) techniques, is presented. The non-linear microwave circuit and the driving pseudo-random modulated (PRM) generator are integrally defined in the frequency domain. The simulation is implemented and performed using commercially available circuit simulation software. The demodulation of the output signal of the LMPA is implemented with optimally matched filters as software-defined demodulation. The simulated dynamic results of a Quasi-MMIC GaN Doherty power amplifier (DPA) are shown and compared to the measured results with a 16-QAM driving signal at 10 MS/s. The time-domain measurement allows the validation of the new simulation technique through the comparison of both the measured and the simulated error vector magnitude (EVM), the left and right adjacent channel power ratios (ACPRs) versus the average output power. This new simulation is then called pseudo-random modulated harmonic balance (PRM-HB) simulation. The full PRM-HB simulation of an LMPA driven by a random modulated signal, performed in the frequency domain at the design circuit level, results in an advanced simulation tool in the frame of the design of RF circuits and subsystems for telecommunication applications.

A Comprehensive Review of Thermal Management in Solid Oxide Fuel Cells: Focus on Burners, Heat Exchangers, and Strategies

Solid Oxide Fuel Cells (SOFCs) are emerging as a leading solution in sustainable power generation, boasting high power-to-energy density and minimal emissions. With efficiencies potentially exceeding 60% for electricity generation alone and up to 85% when in cogeneration applications, SOFCs significantly outperform traditional combustion-based technologies, which typically achieve efficiencies of around 35–40%. Operating effectively at elevated temperatures (600 °C to 1000 °C), SOFCs not only offer superior efficiency but also generate high-grade waste heat, making them ideal for cogeneration applications. However, these high operational temperatures pose significant thermal management challenges, necessitating innovative solutions to maintain system stability and longevity. This review aims to address these challenges by offering an exhaustive analysis of the latest advancements in SOFC thermal management. We begin by contextualizing the significance of thermal management in SOFC performance, focusing on its role in enhancing operational stability and minimizing thermal stresses. The core of this review delves into various thermal management subsystems such as afterburners, heat exchangers, and advanced thermal regulation strategies. A comprehensive examination of the recent literature is presented, highlighting innovations in subsystem design, fuel management, flow channel configuration, heat pipe integration, and efficient waste heat recovery techniques. In conclusion, we provide a forward-looking perspective on the state of research in SOFC thermal management, identifying potential avenues for future advancements and their implications for the broader field of sustainable energy technologies.