System Simulation Research Articles

Appointed-time-control-based three-dimensional parallel approaching guidance for intercepting maneuvering target

This study presents an improved guidance method consisting of the parallel approaching guidance (PAG) and the appointed-time-control-based guidance for addressing the challenge of the three-dimensional guidance with maneuvering target. The relative kinematic equations of the guidance system are divided into the line-of-sight (LOS) angle subsystem and the relative velocity subsystem. For the LOS angle subsystem, the nonsingular finite-time backstepping control (NFTBC) based guidance method is proposed to converge the LOS angles to achieve the PAG. To solve the issue of the singularity and ensure the continuity of the guidance law, a segmented function is designed to obtain the virtual control and further derive the NFTBC. For the relative velocity subsystem, the appointed-time-control-based guidance method is applied with the utilization of the time-to-go to achieve the successful interception at an appointed time for the missile against the target. Besides, the finite-time nonlinear disturbance observer is developed to estimate the target maneuvers. Furthermore, the Lyapunov stability theory is utilized to demonstrate the stability of the closed-loop guidance system. Finally, the simulations of the three-dimensional guidance system are implemented to verify the effectiveness of the proposed method.

The Reduced-Order Modeling Approach for a Double-Damper Concept: A Comparison with a Single Damper for Comfort Analysis

This paper explores the modeling and simulation of an innovative double-damper suspension system, evaluating its effectiveness through different test scenarios. The double damper integrates two individual dampers into a unified assembly. The modeling process involves representing the damper as two distinct dampers and a body block, accounting for the additional degree of freedom introduced by combining the two dampers. Simulink/MATLAB is employed for modeling the pressure, discharge, and force equations of the damper. A simplified quarter-car model is designed to conduct simulations for different road profiles, evaluating the efficacy of this double-damper model. The reduced-order modeling approach, suitable for complex systems like dampers, is utilized. Dedicated mathematical models are utilized to examine both single- and double-damper configurations, with the resulting non-linear equations solved using Newton’s iterative method. The equations derived for the single damper provide the basis for modeling the double-damper system. In this model, two separate dampers, each possessing similar properties, are simulated and considered to be rigidly linked at their connection point. Consequently, it is assumed that a portion of the force and velocity experienced by the lower damper is transmitted to the upper damper, and vice versa. Simulation results demonstrate that the innovative double-damper design outperforms a single passive damper in attenuating the oscillations of both the sprung and unsprung masses. Moreover, this innovative concept offers increased adaptability to balance between ride comfort and road holding, a feature previously limited to passive suspension systems.

An Optimized Dynamic Model Improved Deep Discriminative Transfer Learning Network for Fault Detection in Rotation Vector Reducers

In recent years, recognized fault types using artificial intelligence (AI) models has gradually become one of the mainstream directions in the field of mechanical fault diagnosis. However, it is very difficult to obtain relatively complete fault samples, which limits the application of AI models for complex mechanical systems, such as rotation vector (RV) reducers. To address this issue, physical model-based fault sample generation methods attracted many attentions but still an open problem: the difference in fault samples between numerical simulation and measurement of a physical system needs to be well decreased. Therefore, this article proposes an improved deep discriminative transfer learning network (IDDTLN) for RV reducer fault diagnosis. The presented network is driven by an optimized dynamic model. Firstly, the measurement normal signal and whale optimization algorithm (WOA) are utilized to update the dynamic model parameters of the RV reducer. Secondly, the updated numerical model is employed to calculate simulation fault samples. Finally, simulation samples and unlabeled measurement fault samples are used to train IDDTLN. The trained IDDTLN can accurately identify the unknow measurement fault samples. The data obtained from RV reducer test rigs are utilized to explore the feasibility of the proposed method, and the classification accuracies reach 99.8%.

Analytical model and flow velocity control of electrohydrodynamics system with multi-needle corona discharge

For the flow field distribution and control mechanism generated by the electrohydrodynamics (EHD) system with multi-needle corona discharge, this paper takes the multi-needle EHD pump as the research object, establishes different types of physical models through regional division, constructs multi-physical field coupling relationship, and derives a simplified EHD flow velocity equation suitable for the EHD system with multi-needle corona discharge. Combined with the intelligent optimization method of population evolution, a novel and effective intelligent algorithm is designed for the numerical analysis of the velocity profile distribution of a multi-needle EHD pump, and the flow velocity control law of the multi-needle EHD pump is analyzed by quantitative calculation. The validity of the model and analysis is verified by the electric field and flow field simulation of the multi-needle EHD pump system. The calculation results show that the voltage parameter is more dominant than the electrode spacing parameter in the steady-state flow velocity control of the multi-needle EHD pump, and both the maximum flow velocity and the average flow velocity are superlinearly controlled by voltage. In the design of multi-needle EHD pump with an electrode spacing of 1 cm, the simulation results show that the maximum gas flow velocity of 0.82 m/s can be obtained by providing 5000 V voltage, which verifies the design of a miniaturized multi-needle EHD pump and its feasibility in gas lasers and other application scenarios.

Formal modeling and verification method for Simulink-MDL requirement model

Abstract As complex safety-critical system software becomes more powerful, so does the complexity of its design requirements. Modeling and analyzing design requirements at an early stage has become an integral part of the entire development process for complex safety-critical system software. Simulink is a system modeling and simulation tool used in aviation and other fields. Its model is stored in the form of MDL files. ART (Avionics Requirement Tools) is a requirement modeling and analysis verification tool for the aviation field. It uses VRM (Variable Relation Model) as the theoretical model and can accept VRM and its extended subsets as input models and verify them in the tool. The work of this paper is oriented to the typical software requirements in the field of avionics systems and proposes a formal modeling and verification method for Simulink-MDL models. First, the composition form and structure of the MDL model are analyzed in the article. The functions and semantics of various elements in the model are given. Then a formal modeling method of the MDL model is given. Finally, a simplified version of the flight guidance control system is used for modeling and verification to demonstrate the usability and effectiveness of this method.

Simulation of ordering and diffusion in CrxMoNbTaVW alloys within the framework of the N-body approach when specifying interatomic interactions

Purpose. Development of interatomic potentials for atomistic simulation of alloys based on refractory metals of the V-Cr-Nb-Mo-Ta-W system and atomistic simulation using these ordering and diffusion potentials in CrxMoNbTaVW alloys. Methods. The development of the interatomic potentials of the V-Cr-Nb-Mo-Ta-W system was carried out within the framework of the 𝑁-body approach; To optimize the parameters of the potentials, the results of calculations within the framework of the electron density functional theory using the VASP software package were used as target values; the simulations of ordering and diffusion was carried out using methods of molecular dynamics and the developed We have previously used the combined method of molecular dynamics and the Monte Carlo method (MD+MK). Results. Within the framework of the 𝑁-body approach, potentials are constructed that complement the V-Nb-Mo-W potential system that we built earlier to the V-Cr-Nb-Mo-Ta-W system. The constructed potentials predict the characteristics of alloys in good agreement with experimental data, CALPHAD data and density functional theory data. Using these potentials by the MD+MC method, CrxMoNbTaVW alloys were modeled, where 𝑥 = 0, 0.5, 1, 2 and 3, in the temperature range from 500 ºC to 2300 ºC. The MD+MC calculations and CALPHAD data agreed in the temperature and concentration regions containing one phase of BCC. At a temperature of 1000ºC, MD + MC calculations show the presence of a single BCC phase, which contradicts CALPHAD data, but is consistent with experimental data. The simulation showed that the atomic structure of the CrMoNbTaVW model alloy is self-sufficient to realize the diffusion of components without artificial introduction of vacancies. The absolute values of the diffusion coefficients of the components and the values of the effective activation energy of diffusion in a solid solution of CrMoNbTaVW were calculated for the first time by the method of molecular dynamics. Analysis of the calculated diffusion characteristics indicates that a diffusion mechanism is implemented in the CrMoNbTaVW alloy, which includes coordinated movement of atoms of various grades. Conclusion. The development of methods for atomistic simulations of alloys based on refractory metals of the V-Cr-Nb-Mo-Ta-W system and the results of atomistic simulation of ordering and diffusion in CrxMoNbTaVW alloys have shown their importance for explaining and predicting heat resistance caused by diffusion processes in multicomponent alloys at high temperatures.

Design and simulation of system to prevent runway overrun during landing of civil aircraft

Abstract The airborne runway overrun prevention system predicts landing distance by utilizing real-time aircraft status parameters obtained through onboard sensors. This system offers early warnings to pilots, thereby enhancing flight safety. This paper introduces a design scheme for a runway overrun prevention system considering aircraft dynamic performance. Initially, the study analyzes the basic components and functional requirements of the system based on the Minimum Operational Performance Standard For A Runway Overrun Awareness And Alerting System by the European Aviation Safety Agency. Subsequently, the approach and landing phases are segmented into four stages, providing a methodology for calculating landing distance using a dynamic model. Finally, concluded with a simulation verification conducted on the X-Plane flight simulation platform, we test the visual alarm system of the proposed runway overrun prevention system. Simulation results demonstrate that, during the landing phase, the system dynamically calculates and updates stopping points for each braking mode based on the current braking method. In situations where there is a risk of runway overrun, the system issues timely and well-founded alarms.

Integrating rainfall index-based insurance with optimal crop management strategies can reduce financial risks for Australian dryland cotton farmers

Drought undermines the financial sustainability of farmers. While farmers have adopted various strategies to mitigate some drought impacts, they remain exposed to substantial drought risk. Insurance could be useful in managing climatic risks and for encouraging farmers to take sensible risks (e.g., changing their sowing date to increase yield), but it can be costly. Here, we tested whether the integration of a change in sowing date with rainfall index-based insurance could improve farmer profitability and income stability. We used the Agricultural Production Systems Simulator (APSIM)-Cotton model to simulate cotton lint yields for various sowing dates, taking into account different management strategies, across three dry-land cotton research farm sites – Dalby, Goondiwindi, and Theodore – from 1940 to 2022. We designed the index-based insurance payout when the average rainfall received during the growing season falls below a predefined level, such as the 5th, 10th, or 20th percentile of rainfall. Our study, which involved 3.9 million cotton lint simulations and 3,000 rainfall index-based insurance products, showed that combining a shift in sowing date with insurance can lead to an income improvement of up to 21.5% at some study sites. Additionally, in drought years, the income improvement for farmers who combined optimal sowing dates with rainfall index-based insurance was up to 48.0%. The framework developed in this study could aid in devising financial strategies to enhance farming resilience during climate extremes.

Parameter optimization based on deepwater drilling system simulation: A pre-salt exploration well in Brazil

The vibration of downhole drilling tools is the primary factor that limits the ROP of deep-water salt drilling. Pre-drilling modeling is an essential method for analyzing the dynamic characteristics of the drilling system. Currently, there is limited research on coupling models between the single riser model and drill string model in deepwater drilling dynamics, which hampers offshore drilling dynamics development. In this study, we integrated the dynamic riser model with the flexible drillstring dynamic model, optimized the system's boundary conditions through experiments, and established an advanced full-scale deepwater drilling system. Through virtual drilling simulation analysis and energy flow calculations of the drilling process, we investigated the movement trajectory of the drillstring system at different positions and its correlation with downhole vibration in deepwater drilling. Finally, we performed parameter optimization on Brazil exploration well salt formation. The results indicate that the rotational speed significantly influences the vibration intensity and motion state of both the drill string and downhole drilling tool. Moreover, the kinetic energy and strain energy of BHA effectively reflect the motion state of the downhole drilling tool. When drilling salt and salt intercalation in the Brazil exploration well, the WOB was controlled within 200 kN and 180 kN, and the rotational speed was controlled within 180 rpm and 140 rpm, respectively. This ensured optimal stability and minimized vibrations within the drill string system. The virtual simulation work based on deepwater drilling systems can provide guidance for designing and planning actual drilling operations, as well as proposing reasonable drilling parameters to enhance stability and ROP in the drilling process.

Dual-band low-power RF-to-DC signal converter circuits for energy harvesting

This article presents dual-band low-power, high-sensitive radio-frequency (RF)-to-direct current (DC) signal converter circuits, operating at 2.45 and 5.5 GHz bands, for radio frequency energy harvesting applications. In particular, it focuses on the lumped element and microstrip transmission line model circuits. The lumped element RF-to-DC converter circuit is composed of a dual-band impedance matching circuit, voltage-doubler rectifier, and DC-pass filter with a resistive load of 5 kΩ. This converter circuit gives a DC output voltage of 48 mV at 2.45 GHz and 25 mV at 5.5 GHz on −25 dBm input power. Maximum conversion efficiency is 47% at the 2.45 GHz band and 27% at the 5.5 GHz band when the input power is set to −10 dBm. Circuit design steps, matching conditions, performance parameters, and so on, are presented using Advanced Design System simulation. To validate the concept of the lumped element model, a microstrip transmission line RF-to-DC converter model is simulated and fabricated. It also composes of a dual-band matching network, voltage-doubler, and DC-pass filter with a load resistance of 5 kΩ. At a low input power of −18 dBm, it gives an output voltage of 21 mV in measurement. An appropriate match between the simulation and measurement is noted.

Investigating Arctic Cyclone–Tropopause Polar Vortex Interactions with Idealized Observing System Simulation Experiments

Abstract Arctic cyclones (ACs) are a primary driver of surface weather in the Arctic, contributing to heat and moisture transport and forcing short-term sea ice variability. Still, our understanding of the processes that drive ACs, particularly their large scales and long lifetimes, is limited. ACs are commonly associated with one or more cyclonic tropopause polar vortices (TPVs), potential vorticity (PV) anomalies in the upper troposphere and lower stratosphere that may spur baroclinic development in the surface system, though the exact processes that link the two have yet to be fully explored. In this study, we investigate physical links between TPVs, especially their mesoscale structure and moisture profiles, and ACs with idealized observing system simulation experiments (OSSEs). Starting with a nature run, we simulate different types of dropsonde observations over a TPV during the nascent phase of a nearby AC. The Model for Prediction Across Scales (MPAS) and the Data Assimilation Research Testbed (DART) ensemble adjustment Kalman filter are then used to run experiments to test the impact of these detailed TPV observations. In addition to a control, five main experiments are conducted, assimilating new observations of temperature and humidity. All experiments reduce forecast errors at the surface and throughout the troposphere. Additional humidity observations alter vertical PV distributions, which in turn impact the development of the AC. Experiments with additional temperature observations exhibit improvements in TPV structure and surrounding PV features and produce stronger surface cyclones with skillful TPV forecasts for up to 36 h longer than the control. Significance Statement Arctic cyclones (ACs) are a weather feature that can produce high winds, precipitation, and changes to sea ice cover in the Arctic. As a result, forecasting these storms accurately is important for human and economic interests in the region; however, there are currently gaps in our understanding of how ACs strengthen and persist. In this study, we explore potential links between ACs and weather features higher up in the atmosphere called tropopause polar vortices (TPVs) using computer modeling experiments. This study shows that there are important connections between the characteristics of TPVs and the development of ACs. These findings will be useful for making more accurate forecasts of future events and advancing our knowledge of how sea ice changes relate to the atmosphere.

Dual-band low-power RF-to-DC signal converter circuits for energy harvesting

This article presents dual-band low-power, high-sensitive radio-frequency (RF)-to-direct current (DC) signal converter circuits, operating at 2.45 and 5.5 GHz bands, for radio frequency energy harvesting applications. In particular, it focuses on the lumped element and microstrip transmission line model circuits. The lumped element RF-to-DC converter circuit is composed of a dual-band impedance matching circuit, voltage-doubler rectifier, and DC-pass filter with a resistive load of 5 kΩ. This converter circuit gives a DC output voltage of 48 mV at 2.45 GHz and 25 mV at 5.5 GHz on −25 dBm input power. Maximum conversion efficiency is 47% at the 2.45 GHz band and 27% at the 5.5 GHz band when the input power is set to −10 dBm. Circuit design steps, matching conditions, performance parameters, and so on, are presented using Advanced Design System simulation. To validate the concept of the lumped element model, a microstrip transmission line RF-to-DC converter model is simulated and fabricated. It also composes of a dual-band matching network, voltage-doubler, and DC-pass filter with a load resistance of 5 kΩ. At a low input power of −18 dBm, it gives an output voltage of 21 mV in measurement. An appropriate match between the simulation and measurement is noted.

Design and simulation of solar pumping system using PVsyst, case study: TSABIT - ADRAR in Algeria

In isolated sites, the extension of the electricity network requires a very high capital cost. For agriculture work, irrigation is a necessity. A possible solution is using renewable energy sources like solar power, which is environmentally friendly and available for free. This paper presents the design and simulation of a photovoltaic water pumping system for irrigation of a farm located at a place named Tsabit in Adrar southwest Algeria. A detailed approach for the design of an optimized PV water pumping system based on real water usage data is proposed. Besides, system design work and performance assessment were carried out based on hourly climatic conditions. PV SYST software is used to carry out this work. A comparison was also made between two water pumping systems with and without use of a sun tracker. From the obtained results, the use of this kind of system could have an important contribution in the social and economic development of a country, especially in the presence of a sun tracker device, where we recorded more efficiency.

Design and simulation of solar pumping system using PVsyst, case study: TSABIT - ADRAR in Algeria

In isolated sites, the extension of the electricity network requires a very high capital cost. For agriculture work, irrigation is a necessity. A possible solution is using renewable energy sources like solar power, which is environmentally friendly and available for free. This paper presents the design and simulation of a photovoltaic water pumping system for irrigation of a farm located at a place named Tsabit in Adrar southwest Algeria. A detailed approach for the design of an optimized PV water pumping system based on real water usage data is proposed. Besides, system design work and performance assessment were carried out based on hourly climatic conditions. PV SYST software is used to carry out this work. A comparison was also made between two water pumping systems with and without use of a sun tracker. From the obtained results, the use of this kind of system could have an important contribution in the social and economic development of a country, especially in the presence of a sun tracker device, where we recorded more efficiency.

Digital Protection and Innovative Development Path of Red Culture Resources Based on Distributed Machine Learning Supported by Intelligent Information

As a product of the revolutionary war years, red culture, with its strong vitality, strong cohesion and extraordinary charm, with its incomparable positive energy, resists vulgar and flattering culture, promotes people to rebuild their faith, purify their minds, stimulate their motivation, and promote the process of cultural power. Yan’an, represented by red culture, is rich in resources. This is the holy land of Chinese revolution, the first batch of famous historical and cultural cities named by the State Council, and the three major education bases of patriotism, revolutionary tradition, and Yan’an spirit. The development and utilization of such resources have great political, cultural, educational and economic values. This research is based on the development of red culture, and uses the distributed machine learning system to realize in the system architecture of parameter server. In the distributed system set in this study, node downtime and network interruption are random. When the parameter server system adopts static scheduling, it leads to poor scalability and robustness. The experimental results show that under the intelligent simulation of machine learning system, the development of red culture resources meets the expected assumptions, and the accuracy of the model is relatively high.

Turbine selection for hydraulic energy recovery in the Yuribia dam aqueduct

The recuperation of hydraulic energy in aqueducts is based on utilizing the energy dissipated by hydraulic devices aimed at regulating the flow or pressure within the system, in addition to fulfilling their primary purpose. This paper presents the methodology for the selection of a turbine coupled to a generator for the recovery of hydraulic energy in the aqueduct of the Yuribia dam situated in the state of Veracruz, Mexico. The results of system modeling, simulation, and calculation of the generated energy are presented.

Computer Simulation of a Digital System of Automatic Lighting Control

Computer Simulation of a Digital System of Automatic Lighting Control

A Theoretical Comparison of Alternative Male Mating Strategies in Cephalopods and Fishes.

We used computer simulations of growth, mating and death of cephalopods and fishes to explore the effect of different life-history strategies on the relative prevalence of alternative male mating strategies. Specifically, we investigated the consequences of single or multiple matings per lifetime, mating strategy switching, cannibalism, resource stochasticity, and altruism towards relatives. We found that a combination of single (semelparous) matings, cannibalism and an absence of mating strategy changes in one lifetime led to a more strictly partitioned parameter space, with a reduced region where the two mating strategies co-exist in similar numbers. Explicitly including Hamilton's rule in simulations of the social system of a Cichlid led to an increase of dominant males, at the expense of both sneakers and dwarf males ("super-sneakers"). Our predictions provide general bounds on the viable ratios of alternative male mating strategies with different life-histories, and under possibly rapidly changing ecological situations.

System simulation and parametric analysis of low-concentration coal mine gas fed SOFC-CHP with deoxygenation and enrichment pretreatment

Solid oxide fuel cell (SOFC) combined heat and power (CHP) can efficiently convert low-concentration coal mine gas (LC-CMG) into clean energy, avoiding the greenhouse effect of LC-CMG. Deoxygenation and methane enrichment pretreatment of LC-CMG can prevent explosion and anode oxidation risk. Herein, a chemical process model of LC-CMG fed SOFC-CHP system with the pretreatment was established to predict the performances under different operating conditions. Performance evaluation and exergy analysis were performed considering the use of oxygen-rich gas from the pretreatment at SOFC cathode. The effects of key operation parameters on system performances were investigated in terms of residual oxygen concentration, inlet methane concentration, fuel flow and fuel utilization. The results indicated that net electrical efficiency and heat supply efficiency can respectively reach 49.13 % and 23.90 % using LC-CMG of 15 % CH4 with enhancing effect of oxygen-rich gas at cathode. The decrease of methane concentration and the increase of residual oxygen concentration and flow rate caused the decreased electrical efficiency but the increased heat supply efficiency due to the enlargement of concentration polarization and heat supply. The optimal operation parameters were recognized by comprehensively considering diverse performance indicators. This work can guide system integration and operation optimization of LC-CMG fed SOFC-CHP.

Analysis of Power-to-gas-to-X systems with metal hydride storage based on coupled electrochemical and thermodynamic simulation

Power-to-gas-to-X systems consisting of photovoltaic cells, proton-exchange membrane electrolysis, hydrogen storage based on metal hydrides, proton-exchange membrane fuel cells and buffer batteries could be used to meet heat and electricity demands of homes, businesses, or small districts. The actual size of the individual components and their interplay have to be optimized for the technical and economic feasibility of the overall system. A simulation-based optimization workflow would be a suitable way to accomplish this task, but there are hardly any tools that can simultaneously simulate power, fluid and heat flows of such systems and efficiently perform their optimization. In this paper, a multiphysical energy system simulation and optimization tool is introduced which models electrochemical and thermodynamic processes simultaneously, including modern equations of state and an own numerical solver for the arising differential–algebraic system of equations, and provides new methods for the calibration of parameters of the metal hydride storage, proton-exchange membrane electrolyzer and fuel cell as well as a metamodel-based approach for sizing optimization. As a demonstrator for the novel tool, a simulation model of a hydrogen lab is successfully set up based on experimental results. The novel tool is able to extract polarization and jump curves of the fuel cell, determine a first temperature and pressure dependency of the efficiency of the electrolysis coupled with the metal hydride storage and speed up sizing optimization through metamodeling by a factor 262.1 at 4.9% and 32.7 at 3.3% accuracy.