Entry Vehicle Research Articles

The effect of the ultra-low emission zone on PM2.5 concentration in Seoul, South Korea

As studies regarding the positive effect of Low Emission Zones (LEZs) and people's risk perception about air pollution have increased, more powerful and specific traffic regulation policies have been required. London is the first city in the world to implement an Ultra-low Emission Zone (ULEZ) in addition to the existing LEZ. Benchmarking London's ULEZ, a ULEZ policy was implemented in Seoul, South Korea on December 1, 2019. The goal of the policy is to improve air quality by prohibiting entry of vehicles registered nationwide into Seoul's ULEZ that do not meet a specific emission standard including diesel, gasoline, and LPG fuel-based vehicles. This study analyzed the effect of Seoul's ULEZ policy on the five major atmospheric pollutants (PM2.5, PM10, NO2, CO, SO2, O3) concentration in the zone, particularly focusing on PM2.5 concentration. The analysis employs Difference-in-Differences (DD) approach, comparing data from one year before and after the policy's implementation on December 1, 2019. The findings indicate that Seoul's ULEZ policy resulted in a 9.8% increase in PM2.5 concentrations. Conversely, the policy led to reductions in PM10, NO2, CO, and SO2 concentrations by 12.0%, 17.3%, 5.9%, and 10.8%, respectively, while the effect on O3 was statistically insignificant. These empirical results suggest that the ULEZ may need to incorporate more stringent emission standards, expand its coverage, or introduce additional measures to address the unintended increase in PM2.5 concentration.

Aerodynamic Study of Successful Mars Entry Vehicles

Aerodynamic Study of Successful Mars Entry Vehicles

Analysis on the evolution of cavitation and flow field of vehicles entering water vertically at high speed

A numerical method is developed to consider the effects of fluid force and structural deformation on the flow field. The accuracy of the method is verified by experiments. The cavity evolution process are studied, and the characteristics of the velocity and vortex in the calculated flow field region are analyzed. The motion process of the dynamic wall of the cavity around the vehicle is simulated, and the phenomena of vortex distribution in the wake of the vehicle, instability in the wake of the cavity, and multistage closure of the cavity wall are obtained. It is revealed that the closing of the cavity will cause the velocity of the flow field inside the cavity to be reduced, and the return jet generated by the closing of the cavity will hit the vehicle and cause its attitude to be deflected. The peak velocity of the cavity wall appears at the position of cavity closure and the position of head cavity generation. The vortex scale around the vehicle gradually increases from the head of the body towards the top of the water surface. The research in this paper provides reference for the design of water entry vehicle.

An underwater wake sensing method based on Micro Thermoelectric Generator for enhancing recognition accuracy

The accidental entry and poaching of foreign boats and autonomous underwater vehicles (AUVs) have a detrimental impact on the ecological environment of marine ranching. Currently, there is a need for a monitoring method specifically designed to monitor underwater moving objects (UMOs), such as foreign boats and AUVs, in real-time within marine ranching. Therefore, this paper creatively proposes a method for monitoring UMOs based on thermal tactile of Micro Thermoelectric Generator (MTEG). A thermal tactile perceptual model for propeller wake identification is established and the wake sensing sensor (WSS) is designed. Furthermore, the performance verification experiment of wake sensing and the target classification experiment based on machine learning are carried out to prove the feasibility of the method. The experimental results demonstrate that the propeller wakes are identified with an accuracy of more than 90 % within 30 s in the monitoring terminal. Besides, the method can accurately distinguish between propeller wakes and fish wakes, thereby avoiding false alarms. The reported underwater wake sensing method is a new solution to real-time monitoring and safety early warning of marine ranching.

Entry guidance for spatial no-fly zones avoidance via model-based reinforcement learning

This paper proposes a novel guidance law for hypersonic entry vehicles, considering no-fly zones with height limits. Traditional planar assumptions restrict the flexibility of trajectory design for scenarios like radar avoidance. Besides, the numerical integration proves inefficient for long-term prediction and avoidance. Therefore, a model-based reinforcement learning policy is designed. It offline learns entry dynamics in advance and onboard plans a feasible trajectory. The planner's state includes flight status and no-fly zones; action presents waypoints; and reward ensures constraint while maximizing terminal precision. Then, analytical prediction converts spatial no-fly zone constraints to flight-path angle constraints, improving precision compared to traditional one-step estimates. Finally, the two parts are assembled into the predictor-corrector framework, which gives the augmented guidance commands. While retaining its robustness to bias, our method reduces online optimization calculations and outperforms constraint satisfaction. Experiments show that the model-based method reduces 60% training in offline training compared with proximal policy optimization. Besides, our method is 80% faster than conventional predictor-corrector guidance regarding online computation speed.

Prescribed-time tracking control of Mars entry vehicle with output constraints

This paper studies the prescribed-time output-constrained tracking control problems for Mars entry vehicle systems. By using the properties of the time-varying high-gain function and output-constrained conditions, time-varying barrier Lyapunov functions are constructed. Based on such Lyapunov functions, time-varying adaptive controllers are designed to solve the considered problem. It is proved that the proposed controllers can drive the errors converge to zero in a prescribed time under unknown disturbances, and the control signals are bounded. Both the symmetric and asymmetric cases are considered. Finally, the effectiveness of the proposed methods is illustrated by several numerical simulations.

Composite continuous fast nonsingular terminal sliding mode trajectory tracking control for Mars entry vehicle

SummaryThis paper presents a composite continuous fast nonsingular terminal sliding mode (CCFNTSM) trajectory tracking control method for Mars entry vehicle. Firstly, the trajectory tracking is transferred into the tracking of the pre‐designed drag acceleration. Secondly, the finite‐time disturbance observer (FTDO) is introduced to estimate the matched and mismatched disturbances. And then, the dynamical fast nonsingular terminal sliding mode manifold is designed based on the estimation information. Finally, the CCFNTSM controller is constructed and its continuity is guaranteed by employing the power function of sliding variable to replace the constant switching gain. Numerical simulation results validate the effectiveness of the proposed control method.

Optimal Range Capabilities for Low-Lift-to-Drag Ratio Mars Entry Vehicles

Optimal solutions for maximizing the range of low-lift-to-drag ratio entry vehicles at Mars are explored. Optimal control problems are formulated to consider both vehicles using bank-angle steering as well as alpha-beta steering during entry. Both the maximum downrange and maximum crossrange problems are considered. Results are combined to determine an overall range capability and facilitate comparison to suboptimal constant bank or angle-of-attack and sideslip-angle commands. The resulting optimal control inputs often differ significantly between bank-angle steering and alpha-beta steering vehicles, the latter of which can extend range by lowering drag through sideslip-angle reversals during entry. While control over the in-plane and out-of-plane motion is found to be more decoupled for alpha-beta steering than bank-angle steering, control over the longitudinal and lateral motion is still not completely decoupled for vehicles using alpha-beta steering.

DETECTION OF LPG VEHICLES IN RISKY AREAS WITH COMPUTER VISION TECHNIQUES

Vehicle use is becoming more widespread day by day due to the world population growth. Within the scope of intelligent transportation systems, the information technologies sector and the transportation sector work in an integrated manner to solve the problems caused by the increasing number of vehicles. Data obtained with sensors and cameras are analyzed with artificial intelligence-based information technologies and used in autonomous vehicles, security, traffic management, navigation and passenger information systems. Computer vision enables machines to extract meaningful patterns and relationships from images by combining image processing and deep learning technologies. Computer vision techniques are applied in many fields such as tourism, health, industry, defense, transportation, service, e-commerce, etc. The applications developed provide solutions to various challenges in the transportation sector. For vehicles using Liquified Petroleum Gas (LPG) fuel, the gases in LPG tanks are flammable and pose a potential explosion hazard, especially in certain areas in cities. Entry of LPG vehicles is prohibited in institutions and organizations such as hospitals, shopping malls, hotels that have indoor parking services. The control method of the ban is carried out by assigning a personnel and checking the vehicle trunks. In this study, LPG fueled vehicles were automatically detected using computer vision techniques. Vehicle image data captured by mobile cameras in different provinces in Turkey were trained and compared with four different deep learning models. As a result of training and performance tests on the models, the YOLOv8 model was more effective than the other models with an accuracy of 0.994 mAP and a speed of 11.6 ms. It has been shown to be a stable model in terms of real-time monitoring in real life. It is envisaged that the developed system can contribute to the applications of computer vision techniques as well as benefit the national economy, public life safety and environmental protection.

The Parking Management System

This Parking Management System (PMS) is a comprehensive solution designed to streamline and enhance the efficiency of parking operations. Leveraging advanced technology, the system optimizes the utilization of parking spaces, reduces congestion, and improves overall user experience. Key features include real-time occupancy monitoring, automated payment processing, and smart allocation of available spaces. PMS not only ensures seamless entry and exit for vehicles but also integrates with mobile applications for convenient reservation and navigation. With a focus on sustainability, the system promotes eco-friendly practices by encouraging the use of electric vehicle charging stations and implementing intelligent traffic flow management.In summary, the Parking Management System represents a modern, user-friendly approach to address the challenges associated with urban parking, promoting a more organized and environmentally conscious urban environment. Keywords—Real-time Occupancy Monitoring, Automated Payment Processing

Karakteristik dan Kebutuhan Parkir Pada Taman Kopassus Banten

The research was conducted at Kopassus Park with the aim of determining Parking Characteristics, including Parking Accumulation, Vehicle Parking Volume, Parking Index, Turn Over, Parking Headway, and Parking Space Requirements. The survey was conducted for a duration of seven days. The data obtained consisted of vehicle entry and exit data for both cars and motorcycles. The research results showed that the maximum parking index for cars on June 18, 2023, was 56%, indicating that the demand for car parking space did not exceed the available parking capacity. Similarly, for motorcycles, the maximum parking index on June 23, 2023, was 28.3%, indicating that the demand for motorcycle parking space did not exceed the available capacity. The minimum headway for cars occurred on June 18, 2023, between 2:00 PM and 3:00 PM, with a value of 3 minutes per vehicle, while the minimum headway for motorcycles occurred on June 18, 2023, between 12:00 PM and 1:00 PM, with a value of 3.75 minutes per vehicle. The largest parking space requirement for cars on June 18, 2023, was 161 square meters, with the parking area for cars at Kopassus Park totaling 569.49 square meters, still able to accommodate vehicles during peak hours. The maximum parking space requirement for motorcycles on June 19, 2023, was 34.5 square meters, with the parking area for motorcycles at Kopassus Park totaling 121.20 square meters.

License Plate Detection Based on Open CV

In this project a new approach of automatic vehicle number plate recognition in National Highways and this approach enables the vehicle to automatically pass the NH roads by using object detection, 3D environment construction, virtual line generation, path planning. The system is to monitor the vehicles that are entering and going out of the NH roads. All vehicles have their own unique license plate number, so the abstraction of plate number plays a major role in this system. The vehicle number plate is taken by the tool like machine learning based camera which is placed at the road junctions. The captured image will be processed by the automatic number plate recognition using OCR (optical character recognition) algorithm, here we using Gaussians filters for remove the blueness of the image using a Gaussian kernel suppresses only high-frequency spatial information. Then the entry and exit vehicle number should be recorded. A database is created with the vehicle number. This method is an efficient way of recognizing the vehicle number plate and strengthen the security system. In case of centralized receiver all the entrance records are kept in storage and it will check the presence of theft vehicle entering into the NH roads, it will be noticed and capture the vehicle image and vehicle information’s will be send to authorized person using IMAP (Internet Message Access Protocol). The OCR technique is used to identify the number. This system has many advantages like theft detection, less man power, user friendly, vehicle logging and less processing time.

The planetary protection strategy of Mars Sample Return’s Earth Return Orbiter mission

The Mars Sample Return campaign aims to use three flight missions and one ground element to safely bring rock cores, regolith and atmospheric samples from the surface of Mars to Earth to answer key questions about the geologic and climate history of Mars, including the potential for ancient life. Since its landing in Jezero Crater in 2021, the first mission, NASA’s Mars 2020, has collected a number of samples on the crater floor and on the delta using the Perseverance rover. Subsequent missions would recover the sealed sample tubes, launch them into Mars orbit, and transport them back to Earth. The ground element would be a high-containment facility that would isolate and protect the samples during initial sample characterization, which would include sample safety assessments and time-sensitive scientific investigations. These elements are currently in the planning and design stages of development, and represent an international effort of NASA, the European Space Agency (ESA), and many industry partners. The work presented here provides an overview of the planetary protection strategy of the third flight mission, the ESA-led Earth Return Orbiter, which hosts the NASA-provided Capture, Containment, and Return System. The orbiter would detect and capture the container with up to 30 sealed tubes previously put in Martian orbit, contain them in redundant containers to ensure that no potentially hazardous Mars particles are released, and return them to Earth through an entry vehicle. Both NASA and ESA policies comply with the United Nations’ Outer Space Treaty by planning to protect Earth’s biosphere from any potential adverse effects from material returned from solar system bodies beyond the Earth-Moon system. In the conduct of Mars Sample Return, the two agencies have mutually agreed to apply approaches consistent with their own planetary protection standards to the campaign elements they each provide.

Aspects of biosafety and biosecurity in poultry

The article is devoted to analyzing aspects of biosecurity and biosecurity in the conditions of poultry farms under different poultry-keeping schemes. Production of poultry meat in the EU countries by species is broiler meat – 84.4 %, turkeys – 12.7 %, ducklings – 2.6 %, and other types of slaughtered poultry meat – 0.3 %. Ukraine is one of the five countries in the world that are the largest exporters of poultry meat to the EU, and the volume of poultry meat exported to EU member states in 2023 amounted to 97.469 tons. Compliance with basic biological safety measures is the best way to reduce the risk of spreading infectious diseases, produce safe products, and ensure veterinary food safety. Biosecurity in poultry farming involves some fundamental methods and strategies. Biosecurity is based on two fundamental principles: preventing pathogens from entering the territory of poultry farming (external biosecurity) and their further distribution (internal biosecurity). Factors of external biosecurity are the control of the penetration of biological vectors of the causative agents of poultry infectious diseases (restriction of the entry of vehicles into the farm territory, entry of outsiders, wild animals, rodents, synanthropic birds, and insects). Control of biological vectors of introducing pathogens into the farm is carried out through physical protection barriers (arrangement of fences, fences, installation of protective nets and screens on windows, doors, and ventilation shafts). The factors of internal biosecurity of poultry farms include the system of keeping poultry, proper practice of waste management (timely removal of poultry carcasses, litter, manure, method of waste management), use of hygienic means of bioprotection by employees, hygienic processing between «clean» and "dirty" areas of maintenance facilities, control and management of feed and water, cleaning and disinfection of production facilities. The level of biosecurity depends on the epizootic situation and the industry's provision of modern means of diagnosis, prevention, and treatment. In the conditions of martial law in our country, the principal risks of biological decline are the destruction of homesteads of the population and industrial-type poultry farms; the difficulty of disposing of poultry carcasses, waste from the poultry industry, and household waste following current requirements, as well as changes in the migration routes of synanthropic birds.

A Conceptual Modeling Approach for Performance of Magnetohydrodynamic Drag During Planetary Entry

Future higher-mass Mars missions present numerous engineering challenges and will require significant technological development, particularly of the entry, descent, and landing systems. One such development concept utilizes magnetohydrodynamic interaction with the plasma created during hypersonic planetary entry for energy generation, drag augmentation, and heat-flux mitigation. In this study, a performance estimation methodology for magnetohydrodynamic drag augmentation during Mars entry compatible with conceptual design is developed. A demonstrative investigation utilizing the developed methodology is then conducted, and simulated trajectory results are presented for various entry vehicles and magnetic field strengths. The study results show potential for significant magnetohydrodynamic drag augmentation during hypersonic entry at Mars, with calculated effective ballistic coefficient- reduction factors of up to 4, across entry vehicles ranging in mass from 70 MT to 4 MT. These results show that magnetohydrodynamic drag augmentation can have comparable impact to significant aeroshell diameter increases and also suggest that it could prove an effective form of drag-augmentation control authority by varying the applied magnetic field.

Discrete-Event Drag Modulation Aerocapture for Mars and Titan Missions

Aerocapture is a spaceflight maneuver that uses the atmosphere of a planet or moon to slow down a spacecraft after a single atmospheric pass and capture it into an elliptical orbit around the celestial body. This paper presents a discrete-event drag modulation method for Mars and Titan aerocapture missions. A single-stage jettison is used as a control strategy to modulate the aerodynamic drag for an aerocapture scenario. Entry corridor analysis is performed under worst-case trajectory dispersions for determining the entry flight-path angle. The jettison timing of the high-drag skirt is the single free guidance parameter that adjusts the spacecraft’s trajectory during an aerocapture maneuver. A computationally simple jettison-switching guidance scheme is developed to determine when to jettison the high-drag skirt, and the result is an analytical function that represents the ballistic-coefficient switching curve. The proposed discrete-event drag-modulation strategy is extensively tested using four entry vehicles and three target orbits for Mars and Titan aerocapture scenarios. Monte Carlo simulations show that the simple switching-curve guidance provides performance metrics (apoapsis targeting errors and postexit impulsive maneuvers) that are essentially equal to the performance of more computationally burdensome guidance methods such as an onboard numerical predictor–corrector scheme.

Numerical Study of Plasma Characteristics Under Magnetohydrodynamic Flow Control in Mars Entry

Magnetohydrodynamic flow control is an active thermal protection method for atmospheric entry vehicles. This study examined the plasma characteristics under magnetohydrodynamic flow control and its thermal protection ability at multiple altitudes (20–60 km) on a typical direct Mars entry path using numerical simulation considering the Hall effect. The simulation considered a spherical-conical capsule with an entry velocity of 8 km/s at an altitude of 60 km, equipped with a dipole magnet generating a magnetic field of approximately 0.3 T at the stagnation point of the capsule. The results showed that magnetohydrodynamic flow control can mitigate convective aerodynamic heating at high altitudes (45 km or more), where the high electrical conductivity of the plasma creates strong magnetohydrodynamic interaction. In contrast, at low altitudes (35 km or less), magnetohydrodynamic flow control is ineffective owing to low electrical conductivity. The high electrical conductivity at high altitudes is attributed not only to large flight velocities under low atmospheric pressures but also to the enlargement of the shock layer owing to the strong magnetohydrodynamic interaction, which expands the ionization progression area. Furthermore, the results indicated that considering the Hall effect in the numerical modeling of magnetohydrodynamic flow control in Mars direct entry is essential.

Automated Parking Lot Management System

Automated parking management system, utilizing machine learning for license plate recognition, has simplified the ticket generation and parking space allocation process in large parking areas. It offers a user-friendly experience by swiftly recognizing license plates upon vehicle entry. Furthermore, the system efficiently guides vehicles to the most suitable parking spaces, optimizing usage and alleviating congestion. This innovative approach streamlines these procedures, enhancing user convenience. It also plays a part in creating a more sustainable urban environment by reducing fuel consumption and emissions. To sum it up, our integration of machine learning for license plate recognition provides an efficient and eco-conscious solution to urban parking challenges, making parking hassle-free and environmentally friendly

StreetSavvy: Automated Parking Management System with License Plate Recognition and Pricing

The Parking Charge Calculator represents a meticulously designed system aimed at accurately determining the parking charges for vehicles within a parking facility. This innovative solution leverages Automatic Number Plate Recognition (ANPR) technology in conjunction with a robust database system to streamline the process of identifying vehicles and computing corresponding parking fees. Within the confines of a parking lot, the unique identification of vehicles is facilitated through the extraction of information from license plates. When a vehicle enters the parking lot, the Parking Charge Calculator initiates the retrieval of the license plate number through the ANPR technology. This automated recognition system efficiently captures and records the alphanumeric sequence on the license plate, laying the foundation for subsequent charge calculations. The fundamental mechanism employed by the Parking Charge Calculator involves the multiplication of hourly parking charges by the temporal duration of a vehicle's stay. As the vehicle enters the parking lot, the system records the entry time. Upon the vehicle's departure, the departure time is similarly recorded. The time difference between these two instances becomes a critical parameter in the calculation process. Hourly parking charges, predetermined and configured within the system, serve as the unit of measurement for the calculation. The Parking Charge Calculator multiplies these charges by the elapsed time, providing a precise and automated method for determining the parking fee for a given vehicle. This approach not only ensures accuracy in charge computation but also eliminates the need for manual intervention, promoting efficiency and reducing potential errors. The integration of ANPR technology and a sophisticated database system not only expedites the identification process but also contributes to the overall reliability and security of the Parking Charge Calculator. By automating the parking charge calculation based on vehicle entry and exit times, this system offers a seamless and transparent method for both parking lot operators and vehicle owners, enhancing the overall parking experience and fostering a more technologically advanced approach to parking Management

Utilizing Artificial Neural Networks for Entry Vehicle Aerodynamic Characterization

Determining the dynamic stability of blunt body entry vehicles is a persistent engineering challenge, particularly in the low supersonic to subsonic flight regime where the behavior of the unsteady wake is a primary contributor. Dynamic stability quantities are determined by fitting measurements of a ballistic range campaign or a computational fluid dynamics (CFD) computational experiment to an assumed functional form in order to regress quasi-static stability coefficients. However, this data reduction process has many implicit assumptions that may not hold. This paper explores novel alternatives to the established methods for modeling blunt body aerodynamics. A six-degree-of-freedom CFD-in-the-loop flight model is used to run “virtual ballistic range tests,” fully capturing the relevant flow physics. Feed-forward and time-delay neural network models are fitted to the time-series trajectory and aerodynamic results, which can then be used to predict aerodynamic forces and moments. These models do not have a prescribed functional form and do not assume linearized aerodynamics. The models are evaluated for goodness-of-fit in their aerodynamic and trajectory prediction. The feed-forward neural network model resulted in a better prediction of the virtual ballistic range tests than a traditional database. The time-delay network had good open-loop performance but suffered from closed-loop instability.