Subsystem Design Research Articles

A distributed MPC approach — Local agents decide network convergence

In an earlier work, the Limited Communication-Distributed Model Predictive Control (LC-DMPC) scheme for controlling networks with dynamically coupled and locally constrained linear systems is presented. The scheme has an iterative and cooperative structure in which the systemwide optimum point is achieved by the distributed controllers requiring only coupled agents to cooperate. For assessing the network convergence, it is essential to possess complete information pertaining to all subsystems which has to be available to a central monitor. The current work endeavors to investigate this challenging point by distributing the network convergence within the local agents. With the new version of the algorithm, the convergence of the network is now guaranteed through the dissipativity of the local information exchange dynamics in the iteration domain. This is accomplished by introducing a set of free design variables into the distributed problems which are utilized by the agents to fulfill a simple local LMI problem employing local information only. Despite that the new approach is eliminating the necessity for a centralized observer, it may result in suboptimal local solutions. This is because the convergence of the information sharing loop between the coupled subsystems is insured by the small gain theorem. The new algorithm exhibits enhanced modularity due to the novel introduced convergence condition, implying that any updates to a subsystem physicals or design parameters do not require corresponding updates to neighboring subsystems or the network. The presented concepts are demonstrated by simulating a network of eight interconnected tanks.

Design and implementation of sub-systems of an underwater remotely operated vehicle

Design and implementation of sub-systems of an underwater remotely operated vehicle

Design and analyses of tendon-driven continuum robots for minimally invasive surgery

Continuum robots have great potential to be used for many special applications due to their flexible kinematic structure. The perspective area of utilization is minimally invasive surgery (MIS). One of the main actuation principle of continuum robots is tendon actuation. The paper introduces the developed MISBOT robot for the purposes of MIS monitoring. The paper also presents mechanical design of universal actuation subsystem for tendon-driven continuum robots based on three segmental tendon system. The paper investigates three different mechanical structures of continuum robots from the view of their basic motion properties. The results of the experimental analyses show the better results for continuum robot with elastic structure in comparison with rigid structures, especially from the view of motion repeatability.

Design and Implementation of Space Manipulator Operating Subsystem

Design and Implementation of Space Manipulator Operating Subsystem

Implementation of Model View Controller Architecture in Designing Outcome-Based Education (OBE) Curriculum Management Information System

The development of 21st century education demands the integration of practical and collaborative skills that are relevant to global needs, where the Outcome-Based Education (OBE) approach is the key to achieving measurable and clear learning outcomes. This study focuses on the design of an OBE-based curriculum management information system by implementing the Model View Controller (MVC) architecture and the Laravel framework which aims to overcome the constraints of manual curriculum management at Universitas Maritim Raja Ali Haji, which requires significant time to collect, organize, and analyze data, thus hampering lecturer productivity and interaction with students. The development of the system not only integrates various components of the OBE curriculum, but also creates a collaborative platform in curriculum management. Based on the results of the study that have gone through usability testing with the explorative test method, involving all sub-system designers and stakeholders, this system shows a high level of effectiveness, efficiency, and user satisfaction. Thus, this study is expected to improve the efficiency and effectiveness of OBE curriculum management, which contributes to improving the quality of education at the institution.

Tracking controller of extended chained nonholonomic systems with matched disturbance and input saturation

AbstractThis paper addresses the tracking control for an extended chained nonholonomic system under input saturation and matched disturbances. Specifically, the tracking error dynamic system is split into two subsystems in a cascade form. An integral sliding mode saturated controller is designed in combination with a finite‐time observer (FTDO) to ensure the finite‐time stability of the first subsystem, thereby simplifying the design of the second subsystem. A backstepping‐based adaptive saturated tracking control method is proposed for the second subsystem by incorporating the filter technology. The stability of the resulting closed‐loop system is demonstrated, and the tracking errors can be arbitrarily minimized through the appropriate design parameter selection. The effectiveness of the proposed scheme is validated through simulation and experimental results.

An analytical approach for the analysis of stress wave transmission and reflection in waveguide systems based on Timoshenko beam theory

The paper presents an analytical continuous solution for the analysis of wave refraction and transmission/reflection caused by arbitrarily complex waveguide subsystems. It allows analyzing the way stress wave components are altered as they go through a substructure. The method is new in that it investigates the wave phenomena which govern the dynamic behavior of a structural system explicitly and studies the effectiveness of different serrated and fractal subsystem designs functioning as wave content filters. Timoshenko beam theory is used to model stress wave propagation in waveguides because of its accuracy and consistency over a wide range of vibration frequencies. The versatility of the method is demonstrated using a number of numerical examples characterizing stress wave refraction in single input/single output and single input/multiple output subsystems to study periodic, fractal, and serrated forms. The low computation cost and stable accuracy of the method over a very wide range of frequencies, make it an effective tool for metaheuristic optimization approaches which require massive calculations over many generations. The method is demonstrated to perform seamlessly in coupling with a genetic algorithm optimization framework to determine the optimal serrated configuration of a wave filter.

New Elements of the Control Subsystem Design Procedure Based on Digital Solutions

Relevance. The need to accelerate the creation of new industrial enterprises to compensate for the volume of imported products, the supply of which has stopped since the beginning of the special military operation, turns the design issues of these enterprises into an urgent task. At the same time, this work cannot be carried out on the principles that were adopted in the industrial era, but must carry the innovations that are envisaged by digitalization and components of the "Industry 4.0" concept.Purpose. The article reveals the content of modern digital technologies for building a subsystem of management of industrial enterprises, the consideration of which is necessary in their design.Objectives. In the course of the research, the tasks of developing design procedures for automated enterprise resource management systems, production automation systems and personnel management were solved.Methodology. The research is based on the methods of designing and reforming the main subsystems of industrial enterprises that make up the content of modern concepts of organization and management.Results. As the study showed, in the process of designing an enterprise management subsystem based on digital technologies, it is necessary to perform a number of actions. The main ones are: the definition of business processes that the system should automate, the requirements for the system being implemented; the possibilities of integrating the system with other systems that are supposed to be used at the enterprise being created; additional user training; designing support and development of the system.Conclusions. The use of digital solutions in the design of an industrial enterprise management subsystem makes it possible to create an organization that meets progressive ideas about modern manufacturing business. However, this can only be done by following the recommended technologies.

TECHNOLOGY FOR DETERMINING THE SAFETY OF AMMUNITION IN ACCORDANCE WITH NATO STANDARDS

September 2023 marks 60 years since NATO countries began implementing the principles of ammunition and explosives safety, which are now described in the AASTP and AOR series of publications. This issue is important and significant because during the preparation and operational process, ammunition is exposed to environmental factors that can change the initial parameters and properties of ammunition.
 Today, NATO member states assess the safety of ammunition on the basis of more than 45 NATO Standards that have been developed and implemented.
 The main guiding documents for determining the safety of ammunition are: Standard AOP- 15 Guidelines for the Assessment of Non-Nuclear Ammunition Safety and Suitability for Use by NATO Forces; Standard AAS3P-01 Evaluation Tests for the Safety and Suitability of Non-Nuclear Ammunition; Standard AASTP-3 NATO Guide to Safety Principles for the Classification of Hazards Associated with Military Ammunition and Explosives; Standard AOP- 62 Ammunition Operational Surveillance, General Guidance.
 The article proposes a technology for determining the safety of ammunition based on NATO standards. The proposed technology for determining the safety of ammunition includes two blocks: an assessment process and a program for determining the safety and suitability for use of ammunition: The presented process of safety and serviceability assessment is a specialized problem-solving process; one stage leads to another, taking into account the guarantees that the ammunition is safe and serviceable.
 The evaluation process also has several distinctive features that make it possible to apply it effectively in practice. It is possible to repeat the evaluation stages as often as necessary to achieve the desired results. The process can be applied at any level of system complexity, from the development of a general design concept to the final detailing of a subsystem or component design. It also involves making management decisions between the ideal and the most practical option. In this way, the assessment process provides results that meet the definition of system safety, ensures that the optimal degree of risk elimination is achieved within acceptable operational efficiency, time and cost. The program of safety and suitability testing developed on the basis of these factors should be introduced to the requirements for assessing safety parameters at the national operational level.
 The developed technology is a clear guideline, a step-by-step instruction for military specialists to determine the level of safety of ammunition and its suitability for use.

Kinematic Modeling of a Trepanation Surgical Robot System

This paper presents the concept of a parallel medical robotic service system to assist in a surgical procedure involving precise exploratory trepanation holes in a patient’s skull. The target position and orientation of the trepanation tool in the cranial region is determined using a prior intracranial image analysis using an external medical imaging system. A trepanning actuation system is attached to the end-effector of the parallel robot. The end-effector will act as an accurate positioner for the trepanning drill in the medical intervention area. The conceptual design of the mechanical actuation subsystem of a trepanning robot was developed in the SolidWorks 2022 software environment. The virtual model of the kinematic chain of the robot and the assumed design parameters were used to analytically derive the equations describing the inverse kinematics task. An analysis of the forward kinematics task of the parallel manipulator was also carried out using analytical and numerical methods. A workspace analysis was performed using Matlab based on the kinematic model of the parallel robot. This paper significantly advances the field by presenting the conceptual design of the actuation subsystem, deriving the kinematics equations, conducting a thorough workspace analysis, and establishing a foundation for subsequent control-algorithm development.

Task-Oriented Systematic Design of a Heavy-Duty Electrically Actuated Quadruped Robot with High Performance.

Recent technological progress is opening up practical applications for quadruped robots. In this context, comprehensive performance demands, including speed, payload, robustness, terrain adaptability, endurance, and techno-economics, are increasing. However, design conflicts inevitably exist among these performance indicators, highlighting design challenges, especially for a heavy-duty, electrically actuated quadruped robots, which are strongly constrained by motor torque density and battery energy density. Starting from task-specific holistic system thinking, in this paper, we present a novel task-oriented approach to the design of such kind of robots, incorporating hierarchical optimization and a control-in-the-loop design, while following a structured design path that effectively exploits the strengths of both heuristic and computational designs. Guided by these philosophies, we utilize heuristic design to obtain the approximate initial form of the prototype and propose a key task-oriented actuator joint configuration, utilizing commercially available components. Subsequently, we build a step-wise analytical models considering trajectory optimization and motor heat constraints for optimization of leg length and joint match parameters to achieve a compact performance requirement envelope and minimize redundancy in the construction of task-specific components. Furthermore, we construct a holistic simulation platform with a module control algorithm for typical scenarios to evaluate subsystem results and adjust design parameters iteratively, balancing conflicts and eventually achieving a reliable design specification for detailed subsystem design. Based on these strategies, we develop a heavy-duty electric prototype achieving a maximum speed of 2 m/s in trotting gait with a load weighting over 160 kg and enduring a period of 2 h. The experiment upon the prototype verifies the efficiency of the proposed approach.

Techno-economic optimization of molten salt based CSP plants through integration of supercritical CO2 cycles and hybridization with PV and electric heaters

The present study explores the integration of supercritical CO2 (sCO2) power cycles into Concentrating Solar Power (CSP) plants using molten salt, and the hybridization of these plants with solar photovoltaic (PV) systems through electric heaters. Techno-economic evaluations determined the optimal power cycle configuration and subsystem designs for two different scales and locations and then compared them with state-of-the-art solar power plants. The results show that hybridizing PV with state-of-the-art CSP can lead up to a 22% reduction in the Levelized Cost of Electricity (LCOE) compared to standalone CSP systems. This hybridization and the use of electric heaters are particularly beneficial for small-scale installations and locations with low DNI/GHI ratios. By replacing the steam Rankine cycle with a sCO2 power block, a further 42% reduction in LCOE can be achieved at small scales, even with a simple recuperated cycle. In conclusion, the hybridization with PV and the integration of sCO2 power blocks provide cost benefits despite the temperature limitations imposed by the molten salt. Hybrid PV-CSP plants with sCO2 power blocks prove to be a cost-effective solution for capacity factors exceeding 60%. For lower capacity factors, configurations combining PV with battery energy storage or PV with electric heaters, thermal energy storage, and sCO2 power blocks are preferable options.

Energetic, exergetic, exergoeconomic, environmental and sustainability analyses of a solar, geothermal and biomass based novel multi-generation system for production of power, hydrogen, heating, cooling and fresh water

The present study proposes and investigates a novel solar, geothermal and biomass based multi-generation system producing multiple outputs to generate power, hydrogen, heating, cooling, and fresh water. Parabolic trough solar collectors, a two stages Rankine cycle, two organic Rankine cycles, two absorption cooling systems, a gas turbine system, a once-through (OT) multi stage flash (MSF) desalination unit, a geothermal unit, a heat pump, an electrolyser and a thermal energy storage are used as sub-systems. The novelty of the system is to focus on novel sub-system design pattern for the proposed multi-generation system by using multiple energy inputs as there is a gap about those studies in the literature. The overall system performance is evaluated from energetic, exergetic, exergo-economic, environmental (4E) and sustainability points of view by using the EES software package. The total installed power and hydrogen mass flow rates are 7.76 MW and 3.52 kg/h, respectively. The energy and exergy efficiency values of the overall system are found to be 65.55% and 27.09%. Fresh water flow rate is calculated to be 6.16 kg/s with 10 stages. The overall unit product cost is determined to be 21,79 $/GJ and the overall social ecologic factor is calculated to be 1.37.

Attitude estimation in a modular plug-and-play satellite

Spacecraft modularity is a powerful design methodology for shortening satellite development cycles and reducing costs. The exploitation of standardized and reusable modules, universal interfaces and protocols, generic design, and a set of defined conventions, allows for rapidly integrating a flexible and cost-effective platform with ease of component modifications. Anyhow, the implementation of modularity poses several issues at any level of mission and spacecraft design, including subsystem design. This paper deals with the Attitude Determination and Control Subsystem (ADCS), with a particular accent on making the estimation software independent of any specific requirements dictated by the application in question. In this respect, a generic and reusable Murrell's Multiplicative Extended Kalman Filter (MMEKF) that can operate on different satellites, with diverse estimation requirements, working with changeable integrated ADCS boxes and sensor suites, but without changes either in the equations or in the interface with the rest of the system, has been proposed. The algorithm has been designed to maximize flexibility and ease of applicability to different missions without a priori-knowledge of the actual configuration. The execution of the algorithm is based on a plug-and-play logic in which middleware software enables the automatic discovery of the available sensors and the transmission of required data to the estimation algorithms. An adaptable and modular 3D simulator has been built to test and validate the performance of the generic MMEKF over multiple test cases with assigned configurations. The results of the simulations confirm the capability of the algorithm to meet estimation requirements for each simulated case, without ad-hoc, case-by-case, optimization, or customization.

A new approach to the design of surface subsystems of polymeric insulators for HV and MV apparatus under AC voltage

AbstractThe design of high voltage and medium voltage AC and DC standoff insulators, and, in general, of insulation systems where surface and interface properties are predominant factors, is based on specifications and standards that rely upon long‐term experiences and lab testing. Surface insulating properties depend on electrical and thermal stresses, besides environmental factors, and the inception of extrinsic ageing phenomena, such as partial discharges, can be already a cause of reduced reliability and premature failure (for organic insulating materials). An innovative approach, based on field simulation, discharge modelling, and partial discharge inception measurements is presented by the authors, which can establish a solid basis to optimise insulation design for any type of supply voltage waveform. This method, the three‐leg approach, is applied here to a cable system under AC sinusoidal voltage, but it can work for any type of insulation system, such as bushings, switch gears, transformers, rotating machines, and power electronics boards.

A Multiobjective Feedback Linearization Control of a Cuk Converter

Cuk converter is one of the most common power electronic converters, but its controller design has always been a challenging problem due to its fourth-order nonlinear and nonminimum phase characteristics. In order to solve this problem, this paper proposes a multi-objective feedback linearization control method, which selecting the variables of interest to rebuild the output function to linearize the nonlinear system into a combination of a linear subsystem and a nonlinear subsystem. According to the structural characteristics of these two subsystems, the linear optimal control theory is adopted for the control design of the linear subsystem to make the original nonlinear system have a good output performance, while for the nonlinear subsystem, the coefficient of the output function is adjusted to ensure the stability of the original nonlinear system. The results of simulation and experiment show the feasibility and superiority of using the multi- objective feedback linearization control method to design the nonlinear control law of the Cuk converter.

Iterative design development of a reusable micro-launcher within the RRTB project

The Recovery and Return-To-Base European Reusable Micro-Launcher project, part of the European Commission’s H2020 programme, intends to develop a novel reusable micro launcher system to bring independent and cost-effective access-to-space for the European small satellite market. The multi-disciplinary project focuses on the optimization of aerospike tail-first atmospheric re-entry of the MESO vehicle, together with the design and manufacturing of reusable cryogenic tanks, and the effort is divided into two design loops, where each design loop starts from establishing early design decisions and assumptions so that dedicated subsystem work may progress immediately. The multiple design loop approach allows for unsuitable design decisions, or risky and speculative assumptions to be revised or excluded at the project half-way point, thereby acting as a form of risk management. Throughout the work performed in the first design loop several conclusions were reached. The design presented both novel design features, but also critical issues which became better understood as the fidelity of the subsystem designs and mission analysis increased. These issues ultimately lead to the overall system design and CONOPS to be updated for the second loop, with several of the early design choices being modified, especially through the removal of the EDF landing system, based on the results of the first loop. For the second design loop, the design is updated to alleviate the most critical problem drivers, and to improve the system’s ability to fulfil the top-level requirements and objectives. The updated design uses a Mid-Air Catch approach, and leverages on the heritage of the previous design loop, implementing tailored changes based on the outcome of the trade-offs performed at mission and system levels.

Metamodels to enable renewable energy system consideration within thermal and electrical systems optimization

Emerging infrastructure systems requiring both thermal and electrical energy will be powered by both renewable and conventional energy sources. To consider competitive energy subsystem designs concurrently within the design of a complete infrastructure system, high speed energy subsystem analysis tools and optimization approaches are required. This work demonstrates the use of metamodels for enabling this concurrent design approach. A renewable energy system model is presented for estimating the performance, cost, greenhouse gas emissions, and water consumption of photovoltaic, wind, concentrated solar power, battery, grid, and steam systems for a given location. High-speed metamodel representations of this model are successfully constructed. A few case studies are presented wherein the optimization time and outcomes are compared between the complete model and the metamodels. Both systems identify cheaper, less emitting, and more water efficient systems by deploying renewable energy sources. The metamodels identify competitive systems exceptionally faster than the complete model, four seconds compared to an hour on average, at no detriment to the cost of the identified system. Therefore, metamodels may be used to enable the preliminary concurrent design of emerging infrastructure systems in a computationally manageable way.

Analysis of Explicit Model Predictive Control for Track-Following Servo Control of Lunar Gravity Compensation Facility

The Lunar Gravity Compensation Facility (LGCF) is a critical component in ground tests for a crewed lunar roving vehicle (CLRV). The track-following servo subsystem’s performance is of critical importance in the LGCF, as it needs to achieve high-precision tracking of the CLRV’s fast, wide range of motion in the horizontal direction. The subsystem must also operate within various constraints, including those related to speed, acceleration, and position. These requirements introduce new challenges to both the design and control of the subsystem. To tackle these challenges, this paper employs a Permanent-Magnet Synchronous Motor (PMSM) vector control method based on Space Vector Pulse Width Modulation (SVPWM) to achieve accurate speed tracking. Additionally, this paper presents an Explicit Model Predictive Control (EMPC) strategy for precise position servo control of the track-following system under multi-parameter constraints. The simulation model of the track-following servo subsystem is established based on the above methods. The simulation results demonstrate that the position tracking error of the gravity compensation system, constructed using the above method combined with EMPC control, is less than 0.2 m. The control performance of the EMPC is significantly better than those of the PI and LQI controllers. The influence of errors on the drawbar pull is within 12.5%, and its effect on the compensation force is negligible. These results provide theoretical support for the design of a track-following servo subsystem.

Fuzzy models for quasi‐static calculations of single ground plane coupled CPW by CADMFILT software

AbstractIn this paper, two new subdesign tools including the quasi‐static and fuzzy model calculations for the electrical parameters of the coupled planar transmission lines used in the design of microwave communication subsystems including resonators, filters, and multiplexers are presented for CADMFILT software. Proposed subdesign tools have properties such as electrical parameter calculations for microwave circuit analysis/synthesis, fuzzy logic model applications, comparisons, and graphical demonstrations. The first subdesign tool can calculate the electrical parameters of the coupled planar transmission lines by using the quasi‐static analysis method. The other tool is based on subtractive fuzzy clustering, which can offer approximate solutions as an alternative to numerical and analytical closed‐form expressions of quasi‐static analysis. The proposed subdesign tools have a competent and efficient algorithm to provide fast, accurate, and sensitive results. To test the accuracy of these tools, a coupled coplanar waveguide with a single ground plane structure has been performed. The results obtained from the subdesign tools for both approaches have been compared. The proposed fuzzy logic models use the electrical parameters calculated from the quasi‐static analysis as training and control data files. The accuracy of each model has been tested by error analysis and the validity of the model results has been demonstrated by comparing them with the results of the quasi‐static approach. It is expected that the developed efficient, fast, and versatile subdesign tools will help researchers to simplify their designs by providing a control mechanism in the RF/microwave circuit design processes.