Simulation Test Environment Research Articles

LiDAR-Based Unmanned Aerial Vehicle Offshore Wind Blade Inspection and Modeling

The deployment of offshore wind turbines (WTs) has emerged as a pivotal strategy in the transition to renewable energy, offering significant potential for clean electricity generation. However, these structures’ operation and maintenance (O&M) present unique challenges due to their remote locations and harsh marine environments. For these reasons, it is fundamental to promote the development of autonomous solutions to monitor the health condition of the construction parts, preventing structural damage and accidents. This paper explores the application of Unmanned Aerial Vehicles (UAVs) in the inspection and maintenance of offshore wind turbines, introducing a new strategy for autonomous wind turbine inspection and a simulation environment for testing and training autonomous inspection techniques under a more realistic offshore scenario. Instead of relying on visual information to detect the WT parts during the inspection, this method proposes a three-dimensional (3D) light detection and ranging (LiDAR) method that estimates the wind turbine pose (position, orientation, and blade configuration) and autonomously controls the UAV for a close inspection maneuver. The first tests were carried out mainly in a simulation framework, combining different WT poses, including different orientations, blade positions, and wind turbine movements, and finally, a mixed reality test, where a real vehicle performed a full inspection of a virtual wind turbine.

Effect of cathodic polarizations on the failure behavior of epoxy coating/low alloy steel systems under high hydrostatic pressure

Failure behavior of epoxy coating/low alloy steel systems applied with cathodic polarization at 0.1 MPa and 15 MPa was investigated based on a deep−sea environment simulation test device. The results showed that the diffusion of water into the coating was significantly accelerated by the high hydrostatic pressure under the same polarization potential, and the time of water uptake of the coating that reached saturation was shortened; the coating's physical structure was significantly affected by the high hydrostatic pressure; the generation of highly conductive Fe3O4 was promoted in the corrosion products, which accelerated the metal corrosion process. Under the same hydrostatic pressure, with the negative shift of the polarization potential, the coating protective performance was significantly reduced and metal corrosion was mitigated to a certain extent; the water transport behavior showed a tendency to shorten the time of water uptake of the coating that reached saturation and lengthen the duration of the saturation state, which may be related to a more severe degree of cathodic delamination and the increase of water consumption for cathodic reactions under the coating. In addition, the increase of the weakly conductive α−Fe2O3 content in the corrosion products may cause a reduction in the cathodic protection current at the same polarization potential, resulting in the reduction of the protection effect on the metal.

Design, analysis, and ground deployment test of space deployable mast based on double-layer deployable unit

The space deployable mast has been successfully applied to space equipment such as solar sails and space telescopes. At present, the deployable units of the space deployable mast mostly adopt the configurations of deployable units of FAST (Folding Articulated Square Truss), HIMAT, and ADAM (Able Deployable Articulated Mast). The configuration of the deployable unit is relatively few. Besides, there is a lack of ground micro-gravity environment simulation test devices for space deployable masts. This paper proposes the space deployable mast based on the double-layer deployable unit. Firstly, the configuration design method of the double-layer deployable unit based on the screw theory has been carried out. Three double-layer hybrid mechanisms serving as the basic units of the deployable mast have been obtained. Then, the kinematic and dynamic models of deployment of the space deployable mast have been established. And the deployment simulation based on MATLAB and Simscape has been performed. Furthermore, modal and static simulations have been performed to obtain the fundamental frequencies and maximum deformation displacements of the deployable masts consisting of 1, 2, 4, 8, and 12 units with and without cables. Finally, the ground test device has been developed to carry out the ground deployment test of the space deployable mast in the ground micro-gravity environment. It has been found that the ground test device could achieve the micro-gravity simulation level of 90.5%.

Precision Advancements in Aerial Gliding Vehicles: Modeling to FCS Validation

The growing utilization of unmanned aerial vehicles (UAVs) in military operations has necessitated the development of a suitable weaponry for these kind of platforms. One of the trending categories of such armaments is the aerial gliding vehicle (AGV). AGVs have no propulsion system, consequently, a critical need for a robust flight control system (FCS) tailored to this kind of aerial systems is raised. This research focuses on designing a nonlinear model based controller, starting with the construction of a precise model through practical experiments and the establishment of a dedicated testing and flight simulation environment. Recognizing the limitations of traditional nonlinear dynamic inversion (NDI) due to its dependence on the vehicle model, the modified incremental nonlinear dynamic inversion (MI-NDI) is developed to operate in the presence of wind, model mismatches, and external disturbances. In this research, an extensive testing is conducted in a hardware-in-the-loop (HIL) simulation environment which validates the MI-NDI controller’s superior performance, even in challenging conditions. The research outcomes mark a significant advancement in enhancing autopilot precision for advanced aerial weaponry and unmanned vehicles.

Ambisonic recordings of sound fields from commonly occupied built environments

There is growing use of simulated soundscapes to study human perception, such as for testing hearing aids or cochlear implants. Ambisonics is one method to record and then simulate three-dimensional sound fields with more accurate directional information. In this project, our aim has been to expand the currently available database of ambisonic recordings of soundscapes in built environments. To this end, we have made recordings of sound fields in frequently occupied spaces in the built environment such as classrooms and food courts, using a commercially available ambisonic microphone capturing up to first-order spherical harmonics. While databases of such recordings are available online, many recorded samples are short in duration, typically less than 5 min. long. Furthermore, there are fewer samples taken from occupied spaces in the built environment which are of interest in architectural acoustics. We will review recordings that are already available online and describe our acquired recordings which sample additional spaces and are longer in length. We will share a link to where these can be accessed and downloaded. An ultimate goal is for researchers to utilize these recordings to generate more ecologically valid sound fields when testing human responses in more controllable, simulated test environments.

Simulated vs Actual Application of Symbiotic Model on Six Wheel Modular Multi-Agent System for Linear Traversal Mission

Constant demand for sustainable mechanisms to perform heavy and risky tasks has driven more robotics innovations to arise. Modular reconfigurable robotics system is one of these promising technologies that are continuously explored. Homogeneous types, to be specific, can accomplish similar missions at the same time as individual and heavier missions as an integrated system. This paper presents an analysis of the carrying capacity of a six-wheeled modular multi-agent system using the symbiotic model. The objective is to determine the resulting symbiotic relationship of a given configuration and module state combinations. The results show that the dominant relationship among the trials for linear traversal mission is commensalism. That means, the system neither benefits nor gets harmed from the symbiosis formed. This is true both in simulated and actual test environments although the percentage difference is about 12%. MATLAB Simulink was used for simulation while Maqueen robot in a 3D-printed chassis was used for actual testing. With this study, future configurations for several other missions such as object tracking and ramp climbing can be assessed using the same approach so that possible fault occurrence during operations can be prevented since the developed analysis method is performed prior to the deployment of the system.

Five-Meter Nonmagnetic Telescopic Tubular Mast: Design, Test, and On-Orbit Application

Space deployable masts, as one of the most widely used branches of space deployable structures, can provide driving, positioning, and transmission functions for spacecraft in orbit, which are irreplaceable in complex space activities. The nonmagnetic telescopic tubular mast (NMTTM) is designed and manufactured by the Shenyang Institute of Automation, Chinese Academy of Sciences, aboard the SATech-01 satellite to keep the magnetic probe assembly away from magnetic interference and realize global magnetic field measurement. The NMTTM can withstand complicated vibration and shock during rocket launching in the retracted state of 0.95 m, while it can be stably released and deployed to 5.28 m in orbit. NMTTM was successfully launched into Sun-synchronous orbit on 27 July 2022, fully deployed, and generated the positioning signal after a duration of 19 min and 16 s for the deployment process on 7 November. This paper focuses on the whole process of NMTTM from mission requirements to structure design and manufacture, through to releasing, deployment, and locking technology, environmental simulation tests, up to on-orbit deployment verification, which provides valuable experience for the subsequent development and application of large-scale space deployable masts.

Design of Rocket‐Borne Data Transmission System for Sounding Rocket

The design of a rocket‐borne data transmission system is presented in this article. This data transmission system is used for Meridian Space Weather Monitoring Project II sounding rocket. The major function of this data transmission system is to transmit payload data and rocket telemetry data to ground station. The data transmission system achieves power greater than 4 W (36 dBm). The amplitude unbalance is 1.60% (0.14 dB) and the phase unbalance is 1.74°. Total power consumption of the data transmission system is less than 24 W (28 V power supply). The radiation performance of the data transmission antenna is good. Based on the actual condition of solid rocket, the relevant heat dissipation and vibration reduction measures are designed under the demand of miniaturization. The data transmission system has been tested by performance test, environmental simulation test, system integration test, and other tests; the test results show that it has good working performance, good stability, and high reliability.

Exploration of Quantum Cryptography Security Applications for Industrial Control Systems

Abstract The exploration of security applications of quantum cryptography for industrial control systems is a key research effort aimed at enhancing the security of industrial control systems through quantum cryptography. In this paper, we study the security threats faced by industrial control systems, including network attacks, data leakage, and system tampering, and propose to utilize quantum key distribution and quantum invisible state transfer algorithms to ensure the secure transmission of industrial control system data. The simulation test environment of the upper and lower computers of the industrial control system is built. The quantum encryption and decryption algorithms are deployed in the embedded environment and PCs to test the effectiveness of quantum cryptography to enhance the advanced encryption standard key scheme. The experimental results show that the quantum cryptography technology successfully realizes the encryption and decryption of data, and the total time consumed in the whole process is less than 61.8 seconds, which meets the requirements of a real-time industrial control system. Therefore, quantum cryptography is suitable for protecting field-level data in industrial control systems.

How to diagnose SS7 Protocol Vulnerability in Roaming Networks

As cellular networks spread to various operators in various countries, access to roaming networks by operators in other countries has become easier than before. As security attacks pretending to be roaming operators increased as the number of security attacks increased as the number of hours that were closed between trusted operators was gradually operated openly. By analyzing SS7 vulnerabilities in roaming networks and reenacting them through simulation, this study establishes a security threat scenario in a real commercial communication environment and builds a pre-simulation test environment that can identify and respond to the presence or absence of proactive measures through security analysis. The simulation test environment can be applied to the actual operational environment to reduce attack damage through pre-defense measures by preparing countermeasures against possible security attacks.

Surgical and Radiology Trainees' Proficiency in Reading Mammograms: the Importance of Education for Cancer Localisation.

Medical imaging with mammography plays a very important role in screening and diagnosis of breast cancer, Australia's most common female cancer. The visualisation of cancers on mammograms often forms a diagnosis and guidance for radiologists and breast surgeons, and education platforms that provide real cases in a simulated testing environment have been shown to improve observer performance for radiologists. This study reports on the performance of surgical and radiology trainees in locating breast cancers. An enriched test set of 20 mammography cases (6 cancer and 14 cancer free) was created, and 18 surgical trainees and 32 radiology trainees reviewed the cases via the Breast Screen Reader Assessment Strategy (BREAST) platform and marked any lesions identifiable. Further analysis of performance with high- and low-density cases was undertaken, and standard metrics including sensitivity and specificity. Radiology trainees performed significantly better than surgical trainees in terms of specificity (0.72 vs. 0.35; P < 0.01). No significant differences were observed between the surgical and radiology trainees in sensitivity or lesion sensitivity. Mixed results were obtained with participants regarding breast density, with higher density cases generally having lower performance. The higher specificity of the radiology trainees compared to the surgical trainees likely represents less exposure to negative mammography cases. The use of high-fidelity simulated self-test environments like BREAST is able to benchmark, understand and build strategies for improving cancer education in a safe environment, including identifying challenging scenarios like breast density for enhanced training.

Digital twin for human-robot collaboration enhancement in manufacturing systems: Literature review and direction for future developments

The integration of robots in manufacturing systems known as Human Robot Collaboration (HRC) can provide relevant opportunities in terms of productivity, safety and quality control although there are still many challenges such as integration costs, complexity, safety and workforce concerns, skills gaps and regulatory compliance. Digital Twins (DTs), which are virtual replicas of physical systems, are being explored as a promising solution to address these challenges. Therefore, this paper delves into the potential DTs-based approaches for HRC in manufacturing systems with a focus on their ability to provide a realistic simulation environment for testing and optimizing collaboration strategies. The first part of the study involves a comprehensive literature review devoted to understand how the scientific community perceives the application of DTs for HRC in manufacturing systems and the main trends of this research area are identified. The second part of the study presents a detailed analysis of the currently available commercial simulation software solutions for developing DT models in manufacturing systems for HRC scenarios. The analysis encompassed various aspects such as: the software's capabilities in human and robot simulation, ergonomic and time measurements analysis, data exchange and interoperability with the physical world as well as with other software. The results of the analysis are meant to provide practical insights to researchers and practitioners interested in implementing DTs to enhance HRC in manufacturing systems.

Strengthening mechanism of polyvinyl alcohol fibers on mechanical properties of geopolymer concrete subjected to a wet-hot-salt environment

Concrete materials are subjected to a complex coupled environment of temperature, humidity, and salt ions when in a coastal area during the summer. Geopolymer concrete (GPC), as one of the best alternatives to ordinary silicate concrete, was explored in this study to investigate its mechanical damage under wet-hot-salt environment, and to understand the strengthening mechanism of its mechanical properties by polyvinyl alcohol fibers (PF), which are crucial for the application of GPC in coastal engineering. To achieve this, a series of experiments were conducted to investigate the effect of wet-hot-salt coupled environment and PF content on the mechanical properties of fiber-reinforced geopolymer concrete containing nano-SiO2 (PF-GPC). In the experimental design, a coupled environment of 45 °C temperature, 100% humidity, and 5% NaCl solution content was firstly established for simulation acceleration test by an environmental simulation test chamber. Then different PF volume contents (from 0% to 0.8%) were considered for the cube compressive strength test, split tensile test, elastic modulus test and impact test. The results indicated that the wet-hot-salt environment significantly weakened the mechanical properties of GPC specimens, while the addition of appropriate content of PF effectively mitigated the degradation caused by the wet-hot-salt environment. The compressive strength, splitting tensile strength and elastic modulus of PF-GPC reached their maximum value at a PF content of 0.6%. Particularly, the addition of PF significantly improved the impact resistance of PF-GPC in wet-hot-salt coupled environment, with the highest impact resistance indices observed at a PF content of 0.4%. Moreover, the correlation between the elastic modulus and compressive strength of PF-GPC in wet-hot-salt environment was established by using the power function equation. And based on the applicability of the two-parameter Weibull distribution in the impact life model, an impact damage evolution equation of PF-GPC was established and validated under the wet-hot-salt conditions, which can provide valuable guidance for the design of GPC structures under different damage probabilities. The findings of this study indicated that PF-GPC can be applied in the wet-hot-salt environment, which is important for the low-carbon sustainable development of building materials.

Adaptive Neural Network Global Fractional Order Fast Terminal Sliding Mode Model-Free Intelligent PID Control for Hypersonic Vehicle’s Ground Thermal Environment

In this paper, an adaptive neural network global fractional order fast terminal sliding mode model-free intelligent PID control strategy (termed as TDE-ANNGFOFTSMC-MFIPIDC) is proposed for the hypersonic vehicle ground thermal environment simulation test device (GTESTD). Firstly, the mathematical model of the GTESTD is transformed into an ultra-local model to ensure that the control strategy design process does not rely on the potentially inaccurate dynamic GTESTD model. Meanwhile, time delay estimation (TDE) is employed to estimate the unknown terms of the ultra-local model. Next, a global fractional-order fast terminal sliding mode surface (GFOFTSMS) is introduced to effectively reduce the estimation error generated by TDE. It also eliminates arrival time, accelerates the convergence speed of the sliding phase, guarantees finite time arrival, avoids the singularity phenomenon, and bolsters robustness. Then, as the upper bound of the disturbance error is unknown, an adaptive neural network (ANN) control is designed to approximate the upper bound of the estimation error closely and mitigate the chattering phenomenon. Furthermore, the stability of the control system and the convergence time are proven by the Lyapunov stability theorem and are calculated, respectively. Finally, simulation results are conducted to validate the efficacy of the proposed control strategy.

Evaluation of junior doctors’ retention of knowledge and skills after simulation training in shockable rhythm cardiac arrest in a low-resource setting in Nepal

AimsTo test junior doctors’ abilities to retain advanced life support psychomotor skills and theoretical knowledge in management of shockable rhythm cardiac arrest. MethodsA repeated measure pre-post study design was used with 43 junior doctors, recruited after notifying them with robust method of attraction through flyers, brochures, email and phone calls. Written and performance tests, initial pre-test, immediate post-training, 30-days post-training and 60-days post-training, using simulation-based scenarios with a low-fidelity manikin were used with recording performance of ALS. InstrumentationResuscitation Council UK ALS algorithms and guidelines1 were used in a simulated testing environment. ResultsThere was a highly significant improvement in knowledge immediately after training (p < 0.00), with a net gain of marks from a mean value of 63.2% before training to 87.7% after training by 24.5% (95% CI 19.4, 29.6).There was a gradual decline of retained knowledge with time from immediate post-training over, 30-days and 60-days post-training (p < 0.00). The simulation pre-training assessments and immediate post-training assessments results were statistically significant (p < .00). The mean difference was 44.1% (95% CI 50.11, 38.10). There was a statistically significant decline of the competency with time (p < .00). Unlike for the knowledge test, the drop was significant on the 30th day (p < .00) with a mean difference of −10.5% (95% CI −13.55, −7.40). ConclusionThe training of junior doctors in shockable rhythm cardiac arrest in a low resource setting, improved knowledge and skills in the participants after training. However, retention of knowledge declined at 30 days and more significantly after 60 days and retention of skill was declined more significantly at 30 days.

Design and Fabrication of an Environment Simulation Test Bed for Deep-sea Laser Cladding

The complicated deep-sea high-pressure environment poses a significant challenge for deep-sea laser cladding. To solve this problem, an environment simulation test bed for deep-sea laser cladding is developed in this paper. First, a principle of environment simulation testbed is proposed, which can provide high-pressure water for underwater laser cladding simulation experiments. Based on the principle design, the structure of the environment simulation test bed is modeled in three dimensions, which can carry out underwater laser cladding experiments. Then, the strength of the pressure chamber is analyzed by finite element simulation. Finally, the environment simulation test bed for deep-sea laser cladding is modularly manufactured and integrally packaged. The environment simulation test bed for deep-sea laser cladding can be directly applicable to simulate underwater laser cladding.

Analysis of the Complex Three-Dimensional Flow Structure in the Circulation Pump of the Flow-Making System Based on Delayed Detached Eddy Simulation

As the core component of the flow-making system, the circulating pump has differences in its internal flow structure under different operating conditions, which affects the flow quality of the environmental simulation test area and the authenticity of marine environmental simulation. To explore the internal flow characteristics and outlet evolution characteristics of the circulating pump, this paper uses the DDES (delayed detached eddy simulation) method for numerical simulation. This paper combines BVF (boundary vorticity flow) diagnosis and the limit streamline method to analyze the evolution characteristics of the unstable flow area on the blade surface; it uses the Q criterion to identify the vortex structure inside the pump and analyze its evolution and development laws. Additionally, a quantitative analysis of the flow state of the circulating pump using flow uniformity indexes is performed. The results show that the surface of impeller blades is uniform under 1.0 QN. At 0.7 QN, the evolution process of the blade suction surface BVF is periodic, with a corresponding period of about 2/9 T (0.02 s). At 1.0 QN, the strength and scale of the separated vortices inside the guide vanes are minimized compared to other flow rates, and the scale and strength of the vortices show a decreasing trend along the outer normal direction. The evolution period of the separation vortex on the pressure surface of the guide vane is about 1/3 T (0.033 s) under 1.1 QN and the evolution period of the suction surface of the guide vane is about 2/3 T (0.067 s) under 0.7 QN. The flow uniformity indexes value downstream of the pump outlet under 1.0 QN are very close to the ideal value; with a corresponding value of Ϛi = 0.023, θ¯ = 89.94°, γ = 0.95, λ = 97.9%, the outflow can be approximately regarded as axial uniform flow. The research results can provide theoretical support for the further optimization design of circulating pumps and lay the foundation for the implementation of real systems.

Establishment of Real-Time Simulation Test Environment for Electric Propulsion System of Unmanned Aerial Vehicle Using KDECAN Communication

This paper proposes the construction of a real-time simulation testing environment for the electric propulsion systems of unmanned aerial vehicles (UAVs) using a real-time simulator and KDECAN communication equipment. The proposed real-time simulation environment enables the testing of flight controllers and control algorithms using real-time control communication commands that are identical to those used during actual flight. The KDECAN protocol is analyzed and utilized in the proposed real-time simulation environment for control communication. A reduced-size lift–cruise UAV with eight lift motors (for takeoff) and one cruise motor (for cruising) is used as the target hardware for real-time simulation. This is used to verify the construction of the real-time simulation environment. The final goal of this work is to construct a real-time simulation environment for the stable application of propeller-driven devices, and the findings confirm the independent operation of the lift and cruise motors in the constructed testing environment. Additionally, the real-time monitoring of the state of the electronic speed controllers is verified, suggesting that the testing environment can be utilized as a verification tool for the control algorithms and system design data of electric propulsion systems in actual devices in the future.

Homing Guidance Law Design against Maneuvering Targets Based on DDPG

A novel homing guidance law against maneuvering targets based on the deep deterministic policy gradient (DDPG) is proposed. The proposed guidance law directly maps the engagement state information to the acceleration of the interceptor, which is an end-to-end guidance policy. Firstly, the kinematic model of the interception process is described as a Markov decision process (MDP) that is applied to the deep reinforcement learning (DRL) algorithm. Then, an environment of training, state, action, and network structure is reasonably designed. Only the measurements of line-of-sight (LOS) angles and LOS rotational rates are used as state inputs, which can greatly simplify the problem of state estimation. Then, considering the LOS rotational rate and zero-effort-miss (ZEM), the Gaussian reward and terminal reward are designed to build a complete training and testing simulation environment. DDPG is used to deal with the RL problem to obtain a guidance law. Finally, the proposed RL guidance law’s performance has been validated using numerical simulation examples. The proposed RL guidance law demonstrated improved performance compared to the classical true proportional navigation (TPN) method and the RL guidance policy using deep-Q-network (DQN).

Design and implementation of computer network security protection system based on artificial intelligence technology

Abstract With the rapid development of the Internet, security issues are becoming more and more prominent, and since most information is transmitted through the Internet today, Internet security is particularly important. When the Internet was designed, only mutual compatibility and interoperability between networks were considered, and security issues were not fully considered. As a result, as the Internet continues to grow, security issues are becoming more and more serious. One of the more difficult attacks is the Distributed Denial of Service (DDoS) attack, which has many forms of attacks, is harmful, and is difficult to identify and defend. Therefore, building a global Internet security protection system to achieve effective protection against DDoS attacks is the main work of this research paper. In this paper, we propose an artificial intelligence DDoS attack protection system, which implements a controller and switch auto-detection model by extending the protocol and establishing an optimization model to realize a low-load and low-latency traffic monitoring scheme; for DDoS attacks. We propose the attack inspection algorithm SCVAE based on Variational Encoder (VAE) and Spectral Clustering. in order to mitigate DDoS attack traffic, the protection system uses the QoS traffic control method, builds the application flow hierarchy model, and filters the attack traffic endured by the system by setting the application flow bandwidth limit as well as the traffic priority dual policy. Finally, a Mininet-based simulation test environment is built to evaluate the model, and different test indexes are set for different system modules to evaluate their actual performance. The results of this paper show that in the network traffic monitoring test, the artificial intelligence DDoS attack protection algorithm can respond to the attack more quickly by reducing the average 73ms per sampling compared with other algorithms; in the attack traffic identification test, the comparison accuracy (P) is improved by 15.14%, the accuracy (AC) is improved by 13.26%, the recall (R) is reduced by 9.23%, and the F1 measurement criteria improved by 23%. The test verifies that the artificial intelligence DDoS attack protection system can achieve real-time monitoring of each performance parameter and also illustrates the feasibility and practicality of the research content of this paper, which strengthens the construction of the technical means of Internet security protection and further enhances the Internet security defense capability.