3,994 results on '"ground vehicles"'
Search Results
2. Carpe signum: seize the signal – opportunistic navigation with 5G
- Author
-
Kassas, Zak, Abdallah, Ali, and Orabi, Mohamad
- Subjects
5G ,Navigation ,Ground vehicles ,GPS ,GNSS - Published
- 2023
3. An agent-based simulator for airport ground handling services.
- Author
-
Lao, Xinyun, Shen, Yu, Ran, Xianglai, Zheng, Yuefeng, and Du, Yuchuan
- Subjects
AIRPORTS ,INTERNATIONAL airports ,TURNAROUND time - Abstract
Airport ground handling plays an essential role in shortening the turnaround time for better utilization of aircraft that can reduce the cost per flight. One of the key challenges for improving the efficiency of airport ground operations is to comprehensively simulate the ground handling processes to optimize and evaluate various operation strategies. In this work, we develop an agent-based simulator that specifically focuses on the whole process of airport ground handling from landing to takeoff. It allows different types of agents, i.e. aircraft, ground vehicles, operators, and dispatchers, to execute their own behaviors according to the ground operation characteristics. The interactions among different agents are also modeled according to the specific service agreements. We use the Shanghai Pudong International Airport (PVG) for the case study to demonstrate the interfaces and outputs of the simulator including the simulated flight information, the progress of ground handling services, airfield status, etc. With the developed simulator, we could not only reproduce the real-world operations of different types of services but also have enough potential to optimize and evaluate various airport ground operation strategies under a series of complex scenarios. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
4. Deep Reinforcement Learning-Based 2.5D Multi-Objective Path Planning for Ground Vehicles: Considering Distance and Energy Consumption.
- Author
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Wu, Xiru, Huang, Shuqiao, and Huang, Guoming
- Subjects
ENERGY consumption ,REINFORCEMENT learning ,DEEP reinforcement learning - Abstract
Due to the vastly different energy consumption between up-slope and down-slope, a path with the shortest length in a complex off-road terrain environment (2.5D map) is not always the path with the least energy consumption. For any energy-sensitive vehicle, realizing a good trade-off between distance and energy consumption in 2.5D path planning is significantly meaningful. In this paper, we propose a deep reinforcement learning-based 2.5D multi-objective path planning method (DMOP). The DMOP can efficiently find the desired path in three steps: (1) transform the high-resolution 2.5D map into a small-size map, (2) use a trained deep Q network (DQN) to find the desired path on the small-size map, and (3) build the planned path to the original high-resolution map using a path-enhanced method. In addition, the hybrid exploration strategy and reward-shaping theory are applied to train the DQN. The reward function is constructed with the information of terrain, distance, and border. The simulation results show that the proposed method can finish the multi-objective 2.5D path planning task with significantly high efficiency and quality. Also, simulations prove that the method has powerful reasoning capability that enables it to perform arbitrary untrained planning tasks. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
5. Carpe signum: seize the signal – opportunistic navigation with 5G
- Author
-
Kassas, Zak, Abdallah, Ali, and Orabi, Mohamad
- Subjects
5G ,Navigation ,Ground vehicles ,GPS ,GNSS - Published
- 2021
6. Analysis of Tread ICRs for Wheeled Skid-Steer Vehicles on Inclined Terrain
- Author
-
Jorge L. Martinez, Jesus Morales, Jesus M. Garcia, and Alfonso Garcia-Cerezo
- Subjects
Dynamic simulations ,ground vehicles ,kinematics ,skid-steering ,sloped terrain ,Electrical engineering. Electronics. Nuclear engineering ,TK1-9971 - Abstract
The instantaneous centers of rotation (ICRs) for the two treads of skid-steer vehicles moving with low inertia on hard horizontal terrain almost remain with constant local coordinates, which allows to establish an equivalence with differential-drive locomotion. However, this significant kinematic relationship has not been analyzed yet on sloped ground. One relevant difficulty of studying ICR behavior on inclined terrain, even on a flat surface, is the continuous variation of pitch and roll angles while turning. To overcome this problem, this paper analyzes a dynamic simulation of a skid-steer vehicle on horizontal ground where gravity is substituted by an equivalent external force in such a way that pitch and roll are kept constant. Relevant tread ICR variations on inclined ground have been deduced, which have a significant impact on skid-steer kinematics. These new findings have been corroborated experimentally with a four-wheeled mobile robot that turns on an inclined plane.
- Published
- 2023
- Full Text
- View/download PDF
7. Integrating Real-Time Vehicle and Watercraft Modeling and Simulation Tools for Analysis of Amphibious Operations
- Author
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Monroe, John G., Martin, Keith, Ewing, Mark, Johnston, Morgan, Allison, Mary Claire, Aspin, Zachary, Davenport, Collin, Lynch, Gary, McInnis, David P., McKenna, Tom, Goos, Gerhard, Founding Editor, Hartmanis, Juris, Founding Editor, Bertino, Elisa, Editorial Board Member, Gao, Wen, Editorial Board Member, Steffen, Bernhard, Editorial Board Member, Woeginger, Gerhard, Editorial Board Member, Yung, Moti, Editorial Board Member, Mazal, Jan, editor, Fagiolini, Adriano, editor, Vasik, Petr, editor, Turi, Michele, editor, Bruzzone, Agostino, editor, Pickl, Stefan, editor, Neumann, Vlastimil, editor, and Stodola, Petr, editor
- Published
- 2022
- Full Text
- View/download PDF
8. Multi-objective Model to Distribute Relief Items After the Disaster by Considering Location Priority, Airborne Vehicles, Ground Vehicles, and Emergency Roadway Repair
- Author
-
Momeni, Behnam, Salari, Samira Al-sadat, Aghsami, Amir, Jolai, Fariborz, Filipe, Joaquim, Editorial Board Member, Ghosh, Ashish, Editorial Board Member, Prates, Raquel Oliveira, Editorial Board Member, Zhou, Lizhu, Editorial Board Member, Molamohamadi, Zohreh, editor, Babaee Tirkolaee, Erfan, editor, Mirzazadeh, Abolfazl, editor, and Weber, Gerhard-Wilhelm, editor
- Published
- 2021
- Full Text
- View/download PDF
9. Automatic flower cluster estimation in apple orchards using aerial and ground based point clouds.
- Author
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Zhang, Chenglong, Mouton, Christiaan, Valente, João, Kooistra, Lammert, van Ooteghem, Rachel, de Hoog, Dirk, van Dalfsen, Pieter, and Frans de Jong, Peter
- Subjects
- *
APPLE orchards , *ORCHARDS , *POINT cloud , *COMPUTER vision , *LOCATION data , *ORCHARD management - Abstract
Chemical and mechanical thinning processes have long been used in stone and pome fruit production. During the thinning of apple flowers, growers use chemicals to regulate the tree load. Hand thinning is applied after the June drop to prune trees with excess crop load. The process of thinning can be unpredictable especially in biennial bearing cultivars. Thus, incentives to optimise chemical usage and to reduce expensive manual labour is ever increasing. Ground based machine vision systems have grown in popularity in orchard management due to the level of detail as well as plant coverage they can inspect with. Additionally, unmanned aerial vehicles (UAV) -based remote sensing technology is becoming a popular non-invasive quality inspection solution. This work proposes a framework for combining UAV and ground based RGB image data to detect flowering intensity in a Dutch Elstar apple orchard. The framework, based on point cloud reconstruction, presents automatic point cloud handling techniques as well as automated unsupervised flowering intensity estimation methods. Two linear regression models based on unsupervised machine learning methods were trained and validated from the framework that estimate flowering intensity in the orchard with both models having R2 > 0.65, RRMSE < 20% and p-stat < 0.005 for the correlation between the image derived flower index and the flower cluster number counted in field. The proposed methods provide a novel strategy for guiding flower thinning using simple RGB images and location data only. Moreover, the proposed methods also reveal the flexibility of intra-tree inspection by checking its sub-volumes. • Automatic flower cluster estimation at the tree level with a R2 = 0.7, RMSE < 20. • Ground and aerial point clouds have better performance when combined. • Novel strategy developed for guiding flower thinning in orchard management. • Dataset with aerial and ground images, and field sampling data released. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
- View/download PDF
10. Skin friction topology on ground vehicle models.
- Author
-
Salazar, David M., Liu, Tianshu, and Woodiga, Sudesh
- Abstract
Global luminescent oil-film skin friction meter is used to extract the skin friction topology on two generic ground vehicle models: the Ahmed body and the DrivAer model notchback configuration. Topological structures of skin friction on the top and side surfaces are extracted on both the models at different Reynolds numbers (2.68 × 105, 5.35 × 105, and 8.03 × 105 for the Ahmed body and 2.92 × 105 and 5.84 × 105 for the DrivAer model, corresponding to freestream velocities of 10, 20, and 30 m/s for the Ahmed body and 10 and 20 m/s for the DrivAer model). For the Ahmed body, important features such as forebody separation bubble, longitudinal vortex, and C-pillar vortices and vortex bursting on the rear slant angle are identified. Similarly, for the DrivAer model, in addition to separation and reattachment lines and vortex bursting, more complex vortex interactions in the rear window are revealed. Comparisons of the results obtained for both the models with existing flow visualizations and numerical results are discussed. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
- View/download PDF
11. Numerical investigation of aerodynamic characteristics of generic pickup trucks
- Author
-
Seyfettin Bayraktar and Volkan Atatug
- Subjects
aerodinamik ,hesaplamalı akışkanlar dinamiği ,kara vasıtası ,pikap kamyonet ,direnç ,kaldırma ,aerodynamics ,computational fluid dynamics ,ground vehicles ,pickup truck ,drag ,lift ,Engineering (General). Civil engineering (General) ,TA1-2040 - Abstract
In the present study, aerodynamic properties of modified generic pickup trucks were investigated by means of finite volume method. Steady, three-dimensional and turbulent flows over the pickup trucks were solved by standard k-epsilon turbulence model. An experimentally investigated two-dimensional pickup truck found in the open literature was used as a benchmark case and some modifications were done on it by closing the sides of the bed first. Then a tonneau was used to close the top of the box and finally, a canopy was used to cover the box completely from the tailgate to the cab roof. Simulations reveal that such modifications that were done on the reference case improve the aerodynamic characteristics of the vehicles in terms of drag coefficient. With respect to the original case, the drag coefficient reduces approximately 50%, 30% and 20% by using a canopy, a tonneau and closing all sides except top of the bed. Such decreases in drag coefficient was achieved because every modification prevents the flow separation more effectively around the bed and behind the cab. Regardless of the shape of the bed, the drag coefficient decreases with increasing Reynolds (Re) number up to Re=120103. It seems that this is the critical Reynolds number since drag coefficient does not change considerably with Re any more.
- Published
- 2020
12. Jenerik pikap kamyonetlerin aerodinamik karakteristiklerinin sayısal olarak incelenmesi
- Author
-
Volkan ATATUG and Seyfettin BAYRAKTAR
- Subjects
aerodinamik ,hesaplamalı akışkanlar dinamiği ,kara vasıtası ,pikap kamyonet ,direnç ,kaldırma ,aerodynamics ,computational fluid dynamics ,ground vehicles ,pickup truck ,drag ,lift ,Engineering (General). Civil engineering (General) ,TA1-2040 - Abstract
Bu çalışmada, modifiye edilerek oluşurulmuş kamyonetlerin aerodinamik özellikleri sonlu hacimler metodu ile incelenmiştir. Kamyonetler etrafındaki daimi, üç-boyutlu ve türbülanslı akışlar standart k-epsilon türbülans modeli ile çözülmüştür. Açık literatürde bulunan ve deneysel olarak iki-boyutlu-olarak incelenmiş bir kamyonet referans alınarak, kasası üzerinde bir takım modifikasyonlar yapılmıştır. Bunun için, kasanın yanlarının dışında, üst kısmı da düzlemsel bir yüzeyle örtülmüştür. Son olarak, kasanın üstü, yanlarıyla beraber kamyonet kasasından kabin üst yüzeyine kadar her tarafından tamamen kapatılmıştır. Yapılan simülasyonlar, referans araç üzerinde yapılan değişikliklerin, direnç katsayısı dikkate alındığında, araçların aerodinamik karakteristiklerini iyileştirdiğini ortaya koymuştur. Orijinal duruma nazaran aracın kabinden kasanın üstüne kadar kaplanmasıyla %50, kasanın arka, üst ve yanlarının kapatılmasıyla %30 ve sadece kasanın arka ve yanlarının kapatılıp üst tarafının açık bırakılmasıyla direnç değerinde, %20 düşüş sağlanmıştır. Dirençteki bu azalmaların sebebi, kasa etrafında ve kasa ile kabin arasındaki bölgede akış ayrılmasının önlenmesidir. Kasanın şekli ne olursa olsun, direnç katsayısı Reynolds (Re) sayısının Re=120103‘e kadar arttırılmasıyla azalmıştır. Bu değerden sonra direnç değerleri Re sayısıyla artık çok fazla değişmediği için bu değerin kritik Reynolds sayısı olduğu görülmüştür.
- Published
- 2020
13. Inertial Force Actuator Applications for Active Vehicle Suspensions
- Author
-
McCrone, David Jordan
- Subjects
Mechanical engineering ,Active Suspension ,Ground Vehicles ,Optimal Control - Abstract
The application of Inertial Force Actuators (IFAs) to vehicle dynamics is investigated. Theseare modeled as translational motors with a small proof mass attached such that forces applied bythe actuator to the vehicle result in motion of the proof mass in inertial space. IFAs are shownto provide specific benefits compared to traditional active suspensions, which exhibit deleteriouseffects on secondary vehicle signals while pursuing their primary objectives. Since IFAs can be highpower and generate high force magnitudes, and are constrained only by their internal stroke andforce limits, their application is well suited for zero-mean band-limited white noise inputs such asfrom a vehicle roadway. The suspension control problem is studied with the incorporation of IFAsin cooperation with traditional actuators in order to meet the vehicle objectives hierarchy. Modernand classical control theory investigate the application of IFAs to control various vehicle outputsignals. High order vehicle simulation models are generated, and used to validate the controlledsystem.
- Published
- 2022
14. Online Assessment of Driving Riskiness via Smartphone-Based Inertial Measurements.
- Author
-
Gelmini, Simone, Strada, Silvia C., Tanelli, Mara, Savaresi, Sergio M., and Biase, Vincenzo
- Abstract
Assessing the driving-style from dynamic data is a well established line of research, which has tackled the description of risky behaviours, the profiling of energy-consumption habits, and the detection of different driver’s characteristics from the analysis of motion data. In the last years, as smartphone ownership has become widespread, such an assessment has been increasingly relying on the measurements taken from the inertial sensors on board of the smartphone itself. This work stands in this context, and it aims to design a 4-dimensional driving-style assessment for insurance purposes. The main contribution is adding, to more common proxies of risky-driving, the dimension of smartphone usage, the detection of which is performed through an appropriate processing of smartphone-based inertial sensors, thus not relying on privacy-sensitive monitoring of phone usage behavior. Physics-based, fine-grained dynamic features are used to classify the overall riskiness of the driving-style, thus providing a comprehensive insight into the most discriminating features. The study is based on experimental data, collected over more than five thousands kilometers of varied car trips. [ABSTRACT FROM AUTHOR]
- Published
- 2021
- Full Text
- View/download PDF
15. Autonomous Ground Vehicle Path Planning in Urban Environments Using GNSS and Cellular Signals Reliability Maps: Simulation and Experimental Results.
- Author
-
Ragothaman, Sonya, Maaref, Mahdi, and Kassas, Zaher M.
- Subjects
- *
CELL communication , *GLOBAL Positioning System , *URBAN planning , *ROAD closures , *SOIL vibration , *AUTONOMOUS vehicles ,URBAN ecology (Sociology) - Abstract
A framework for autonomous ground vehicle (AGV) path planning using global navigation satellite systems (GNSS) signals and cellular long-term evolution (LTE) signals is evaluated through several simulations and experiments. The objective of path planning is to prescribe the optimal path for the AGV to follow to reach a desired target point. Optimality is defined as the shortest distance, while minimizing the AGV's position estimation error and guaranteeing that the uncertainty about its position is below a desired threshold. Path planning is prescribed via signal reliability maps, which provide information about regions where large errors due to cellular signal multipath or obstructed GNSS line-of-sight are expected. Simulation results are presented demonstrating that utilizing ambient cellular LTE signals together with GNSS signals 1) reduces the uncertainty about the AGV's position, 2) increases the number of feasible paths to choose from, which could be useful if other considerations arise (e.g., traffic jams and road blockages due to construction), and 3) yields significantly shorter feasible paths, which would otherwise be infeasible with GNSS signals alone. Experimental results on a ground vehicle navigating in downtown Riverside, CA, USA, are presented demonstrating a close match between the simulated and experimental results. [ABSTRACT FROM AUTHOR]
- Published
- 2021
- Full Text
- View/download PDF
16. Architecture of the Ground Vehicle Hybrid Drive System
- Author
-
Zou, Yuan, Li, Junqiu, Hu, Xiaosong, Chamaillard, Yann, Zou, Yuan, Li, Junqiu, Hu, Xiaosong, and Chamaillard, Yann
- Published
- 2018
- Full Text
- View/download PDF
17. Introduction
- Author
-
Zou, Yuan, Li, Junqiu, Hu, Xiaosong, Chamaillard, Yann, Zou, Yuan, Li, Junqiu, Hu, Xiaosong, and Chamaillard, Yann
- Published
- 2018
- Full Text
- View/download PDF
18. Environmental Monitoring and Simulation of Infrasound Generating Mechanism of Traffic Flow
- Author
-
Marina Vladimirovna Grafkina, Boris Nikolaevich Nyunin, and Evgeniya Yurevna Sviridova
- Subjects
infrasound ,ground vehicles ,environmental monitoring ,infrasound pressure ,shedding of vortices ,drag coefficient ,wheel harmonics ,driving speed ,Environmental technology. Sanitary engineering ,TD1-1066 ,Environmental sciences ,GE1-350 - Abstract
Ground vehicles are the main sources of noise and infrasound in residential areas. Numerous published works are devoted to studies of audible sound, its sources in vehicle, and development of measures to its reduction. The authors believe that the problem of infrasound occurrence and propagation in residential areas and, hence, its negative impact on humans and ambient environment is underestimated. Development of predictions and experimental methods of studying infrasound generating mechanism and environmental monitoring of this negative factor are an urgent issue. Significant portion of acoustic emission from a vehicle is comprised for infrasound and low frequency range. Internal and external infrasound of vehicle has been measured. Prediction model has been proposed and the influence of vehicle design features on infrasound level has been estimated. Predictions of external infrasound generating mechanism of vehicles reveal that its frequency and level depend on driving speed, drag coefficient, vehicle body length, Strouhal number. Important sources of vehicle infrasound are wheels which execute rotation and progressive movement in airstream. Five wheel harmonics have been calculated for motor vehicles at various driving speeds, the existing dependences are detected. It has been demonstrated that the regulatory levels of infrasound can be exceeded only in residential areas adjacent to traffic flow with driving speeds higher than 80 km/h. The results of field studies of infrasound level on the streets of Moscow are presented. Recommendations on development of environmental monitoring and main approaches to reduce infrasound in urban environment are given
- Published
- 2019
- Full Text
- View/download PDF
19. Sideslip angle estimation of ground vehicles: a comparative study.
- Author
-
Liu, Jizheng, Wang, Zhenpo, Zhang, Lei, and Walker, Paul
- Abstract
Vehicle sideslip angle is a major indicator of dynamics stability for ground vehicles; but it is immeasurable with commercially‐available sensors. Sideslip angle estimation has been the focus of intensive research in past decades, resulting in a rich library of related literature. This study presents a comprehensive evaluation of state‐of‐the‐art sideslip angle estimation methods, with the primary goal of quantitatively revealing their strengths and limitations. These include kinematics‐, dynamics‐ and neural network‐based estimators. A hardware‐in‐loop system is purposely established to examine their performance under four typical manoeuvres. The results show that the dynamics‐based estimators are suitable at low vehicle velocities when tires operate in the linear region. In contrast, the kinematics‐based methods yield superior estimation performance at high vehicle velocities, and the inclusion of the dual GPS receivers is beneficial even when there is large disturbance to the steering angle. Of utmost importance, it is experimentally manifested that the neural network‐based estimator can perform well in all manoeuvres once the training datasets are properly selected. [ABSTRACT FROM AUTHOR]
- Published
- 2020
- Full Text
- View/download PDF
20. Numerical investigation of aerodynamic characteristics of generic pickup trucks.
- Author
-
ATATUG, Volkan and BAYRAKTAR, Seyfettin
- Subjects
- *
FINITE volume method , *REYNOLDS number , *TURBULENCE , *FLOW separation , *COMPUTATIONAL fluid dynamics , *DRAG coefficient - Abstract
In the present study, aerodynamic properties of modified generic pickup trucks were investigated by means of finite volume method. Steady, three-dimensional and turbulent flows over the pickup trucks were solved by standard k-epsilon turbulence model. An experimentally investigated two-dimensional pickup truck found in the open literature was used as a benchmark case and some modifications were done on it by closing the sides of the bed first. Then a tonneau was used to close the top of the box and finally, a canopy was used to cover the box completely from the tailgate to the cab roof. Simulations reveal that such modifications that were done on the reference case improve the aerodynamic characteristics of the vehicles in terms of drag coefficient. With respect to the original case, the drag coefficient reduces approximately 50%, 30% and 20% by using a canopy, a tonneau and closing all sides except top of the bed. Such decreases in drag coefficient was achieved because every modification prevents the flow separation more effectively around the bed and behind the cab. Regardless of the shape of the bed, the drag coefficient decreases with increasing Reynolds (Re) number up to Re=120×103. It seems that this is the critical Reynolds number since drag coefficient does not change considerably with Re any more. [ABSTRACT FROM AUTHOR]
- Published
- 2020
- Full Text
- View/download PDF
21. A survey on convex optimization for guidance and control of vehicular systems.
- Author
-
Wang, Zhenbo
- Subjects
- *
FORMATION flying , *SPACE robotics , *SPACE vehicles , *LANDING (Aeronautics) , *AUTONOMOUS vehicles , *HYPERSONIC planes , *MATHEMATICAL optimization , *TRAJECTORY optimization - Abstract
Guidance and control (G&C) technologies play a central role in the development and operation of vehicular systems. The emergence of computational guidance and control (CG&C) and highly efficient numerical algorithms has opened up the great potential for solving complex constrained G&C problems onboard, enabling higher level of autonomous vehicle operations. In particular, convex-optimization-based G&C has matured significantly over the years and many advances continue to be made, allowing the generation of optimal G&C solutions in real-time for many vehicular systems in aerospace, automotive, and other domains. In this paper, we review recent major advances in convex optimization and convexification techniques for G&C of vehicular systems, focusing primarily on three important application fields: (1) Space vehicles for powered descent guidance, small body landing, rendezvous and proximity operations, orbital transfer, spacecraft reorientation, space robotics and manipulation, spacecraft formation flying, and station keeping; (2) Air vehicles including hypersonic/entry vehicles, missiles and projectiles, launch/ascent vehicles, and low-speed air vehicles; and (3) Motion control and powertrain control of ground vehicles. Throughout the paper, we draw figures that illustrate the basic mission concepts and objectives, introduce key equations that characterize the feature of each class of problems and approaches, and present tables that summarize similarities and distinctions among the problems, ideas, and methods. Where available, we provide comparative analyses and reveal correlations between different applications and technical approaches. Finally, we identify open challenges and issues, discuss potential opportunities, and make suggestions for future research directions. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
22. Vision-Based Autonomous Landing for Unmanned Aerial and Ground Vehicles Cooperative Systems
- Author
-
Man-On Pun, Guanchong Niu, Qingkai Yang, and Yunfan Gao
- Subjects
Scheme (programming language) ,Control and Optimization ,Vision based ,business.industry ,Computer science ,Mechanical Engineering ,Real-time computing ,Biomedical Engineering ,Ground vehicles ,Velocity controller ,Computer Science Applications ,Human-Computer Interaction ,Artificial Intelligence ,Control and Systems Engineering ,Global Positioning System ,Computer Vision and Pattern Recognition ,State (computer science) ,Quadratic programming ,business ,computer ,computer.programming_language ,Control-Lyapunov function - Abstract
In this work, we consider a cooperative system in which UAVs perform long-distance missions with assistance of unmanned ground vehicles (UGVs) for battery charging. We propose an autonomous landing scheme for the UAV to land on a mobile UGV with high precision by leveraging multiple-scale Quick Response (QR)-codes for different altitudes. These QR-codes support the acquisition of the relative distance and direction between the UGV and UAV. As a result, the UGV is not required to report its accurate state to the UAV. In contrast to the conventional landing algorithms based on the global positioning system (GPS), the proposed vision-based autonomous landing algorithm is available for both outdoor and GPS-denied scenarios. To cope with the challenge on the moving platform landing, a quadratic programming (QP) problem is formulated to design the velocity controller by combining a control barrier function (CBF) and a control Lyapunov function (CLF). Finally, both extensive computer simulation and a prototype of the proposed system are shown to confirm the feasibility of our proposed system and landing scheme.
- Published
- 2022
23. Environmental Monitoring and Simulation of Infrasound Generating Mechanism of Traffic Flow.
- Author
-
Grafkina, Marina Vladimirovna, Nyunin, Boris Nikolaevich, and Sviridova, Evgeniya Yurevna
- Subjects
INFRASONIC waves ,ENVIRONMENTAL monitoring ,TRAFFIC flow ,STREETS ,MOTOR vehicle driving ,DRAG coefficient ,ACOUSTIC emission - Abstract
Ground vehicles are the main sources of noise and infrasounds in residential areas. Numerous published works are devoted to the studies of audible sound, its sources in vehicle, and development of measures to its reduction. The authors believe that the problem of infrasound occurrence and propagation in residential areas and - hence - its negative impact on humans and ambient environment is underestimated. Development of predictions and experimental methods of studying the infrasound generating mechanism and environmental monitoring of this negative factor are an urgent issue. A significant portion of acoustic emission from a vehicle comprises infrasound and low frequency range. Internal and external infrasound of vehicle were measured. A prediction model was proposed and the influence of vehicle design features on the infrasound level was estimated. Predictions of the external infrasound generating the mechanism of vehicles reveal that its frequency and level depend on driving speed, drag coefficient, vehicle body length, and Strouhal number Wheels, which execute rotation and progressive movement in airstream, are important sources of vehicle infrasound. Five wheel harmonics were calculated for motor vehicles at various driving speeds, the existing dependences are detected. It was demonstrated that the regulatory levels of infrasound can be exceeded only in residential areas adjacent to traffic flow with driving speeds higher than 80 km/h. The results of field studies of infrasound level on the streets of Moscow were presented. Recommendations on the development of environmental monitoring and main approaches to reduce infrasound in urban environment were given. [ABSTRACT FROM AUTHOR]
- Published
- 2019
- Full Text
- View/download PDF
24. Sub‐optimal switching in anti‐lock brake systems using approximate dynamic programming.
- Author
-
Sardarmehni, Tohid and Heydari, Ali
- Abstract
Optimal scheduling in an anti‐lock brake system of ground vehicles is performed through approximate dynamic programming for reducing the stopping distance in severe braking. The proposed optimal scheduler explicitly incorporates the hybrid nature of the anti‐lock brake system and provides a feedback solution with a negligible computational burden in control calculation. To this goal, an iterative scheme, called the value iteration algorithm, is used to derive the infinite horizon solution to the underlying Hamilton–Jacobi–Bellman equation. Performance of the proposed method in control of the brake system is illustrated using both linear‐in‐parameter neural networks and multi‐layer perceptrons. Simulation results demonstrate potentials of the method. [ABSTRACT FROM AUTHOR]
- Published
- 2019
- Full Text
- View/download PDF
25. Control of air-ground convoy subject to communication time delay.
- Author
-
Neto, Armando Alves, Mozelli, Leonardo A., and Souza, Fernando O.
- Subjects
- *
CARRIERS , *TIME delay systems , *DRONE aircraft , *REMOTELY piloted vehicles - Abstract
The problem associated with line formation (convoy) control among a team of aerial and ground vehicles is addressed by considering the fact that the vehicles share information with each other via communication channels that can be corrupted because of time delay. Among other results, we present rules for designing a decentralized control law that provides convoy stability, ensuring null formation error at steady state under the condition of constant speed, for the leader, compensating time-delay effects on the communication flow among the following vehicles. The results have been verified for convoy designs based on "look-ahead" topologies, in which each agent knows only the states of the preceding vehicles in the formation. The effectiveness of the proposed rules is finally illustrated by a simulation experiment involving a team of Unmanned Aerial Vehicles (UAVs) and Unmanned Ground Vehicles (UGVs), executing a scouting mission. [ABSTRACT FROM AUTHOR]
- Published
- 2019
- Full Text
- View/download PDF
26. Characterization of machine learning algorithms for slippage estimation in planetary exploration rovers.
- Author
-
Gonzalez, Ramon, Chandler, Samuel, and Apostolopoulos, Dimi
- Subjects
- *
ROVING vehicles (Astronautics) , *MACHINE learning , *COMPUTER algorithms , *BIG data , *DATA analysis - Abstract
Highlights • Comparison of eleven well-known machine learning algorithms. • Influence of tires, speed, soil, and mounting position of sensors. • Validation by means of a real planetary exploration rover (LATUV rover). • Deep discussion with the lessons learned. Abstract This paper presents a comprehensive comparison of well-known machine learning algorithms for estimating discrete slip events associated with individual wheels in planetary exploration rovers. This analysis is performed with various tuning configurations for each algorithm (55 setups). This research also shows the key role that environment plays in the performance of the learning algorithms: rover speed (0.05–0.25 [m/s]), type of terrain (gravel vs. sand), and tire type (off-road tires vs. smooth tires). These contributions are validated by using a broad data set collected using a planetary rover equipped with proprioceptive sensing. This work not only identifies the best algorithm to be deployed for discrete slip estimation, but it also helps with the selection and the mounting position of the sensing systems to be employed in future robotic planetary missions. [ABSTRACT FROM AUTHOR]
- Published
- 2019
- Full Text
- View/download PDF
27. Classification of UAV-to-ground vehicles based on micro-Doppler signatures using singular value decomposition and reconstruction.
- Author
-
Zhu, Lingzhi, Chen, Si, Zhao, Huichang, and Zhang, Shuning
- Subjects
- *
SINGULAR value decomposition , *HILBERT-Huang transform , *MICRO air vehicles , *SUPPORT vector machines , *DRONE aircraft - Abstract
Abstract Classification of ground vehicles from the unmanned aerial vehicles (UAVs) is the basis for local precision strikes. In this paper, a method based on micro-Doppler effect which provides unique information of targets is proposed for ground vehicles classification. Firstly, models describing the air-to-ground relationship between ground vehicles and the UAV are built to derive mathematical expressions of radar echo signals. Secondly, Singular Value Decomposition (SVD) is utilized to analyze micro-Doppler components of the ground wheeled vehicle and the ground tracked vehicle respectively. Thirdly, according to classify requirements, specific signal components are restored by Singular Value Reconstruction (SVR). Seven micro-Doppler features are extracted from reconstructed signals. At last, these features are sent to Support Vector Machine (SVM) classifier. Compared with current related methods such as Empirical Mode Decomposition (EMD) and multi-level wavelet decomposition (MWD), experimental results in different cases illustrate the effectiveness of this method. Discrimination performance under various signal-to-noise ratios (SNRs) also proves the robustness of proposed method. [ABSTRACT FROM AUTHOR]
- Published
- 2019
- Full Text
- View/download PDF
28. A Cloud Big-Data-Driven Dynamics Control Approach for Unmanned Ground Vehicles for Safety Improving
- Author
-
Wu Jiafeng, Ni Jun, Xu Yang, and Jiang Xu
- Subjects
business.industry ,Computer science ,Mechanical Engineering ,Automotive Engineering ,Real-time computing ,Control (management) ,Big data ,Cloud computing ,Ground vehicles ,business ,Computer Science Applications - Published
- 2022
29. Hemispherical InfraRed (IR) Marker for Reliable Detection for Autonomous Landing on a Moving Ground Vehicle From Various Altitude Angles
- Author
-
Juho Kim, Jongho Lee, Jeounggeun Lim, Taeyeon Lee, Sangjin Pyo, and Jehong Lee
- Subjects
Planar ,Altitude ,Control and Systems Engineering ,Infrared ,Range (aeronautics) ,Transmittance ,Environmental science ,Radius ,Electrical and Electronic Engineering ,Radiation ,Ground vehicles ,Computer Science Applications ,Remote sensing - Abstract
Autonomous landing of a quadrotor aerial vehicle on a mobile ground vehicle is a key function required for heterogeneous cooperation between air and ground vehicles to extend mission range. Wide angle detection and localization of mobile landing spot can improve reliability and convenience in autonomous landing processes. In this study, we present a hemispherical InfraRed (IR) marker designed and built for reliable detection and autonomous landing from various altitude angles. IR light has higher transmittance and the hemispherical design provides wide angle radiation. We present the fabrication process of the hemispherical marker from a planar flexible film, followed by full system integration on the ground vehicle. The relatively compact (radius: 2.25 cm, height: 2.3 cm) marker is detectable from wide altitude angles (0-180) and detectable even when covered by thin foreign objects such as fallen leaves or plastic bags. Outdoor experiments with full system integrating autonomous air and ground vehicles demonstrated the feasibility of this approach to autonomous landing for heterogeneous cooperation.
- Published
- 2022
30. Reactive Navigation on Natural Environments by Continuous Classification of Ground Traversability
- Author
-
Jorge L. Martínez, Jesús Morales, Manuel Sánchez, Mariano Morán, Antonio J. Reina, and J. Jesús Fernández-Lozano
- Subjects
field navigation ,ground vehicles ,traversability classification ,robotic simulation ,3D point cloud ,Chemical technology ,TP1-1185 - Abstract
Reactivity is a key component for autonomous vehicles navigating on natural terrains in order to safely avoid unknown obstacles. To this end, it is necessary to continuously assess traversability by processing on-board sensor data. This paper describes the case study of mobile robot Andabata that classifies traversable points from 3D laser scans acquired in motion of its vicinity to build 2D local traversability maps. Realistic robotic simulations with Gazebo were employed to appropriately adjust reactive behaviors. As a result, successful navigation tests with Andabata using the robot operating system (ROS) were performed on natural environments at low speeds.
- Published
- 2020
- Full Text
- View/download PDF
31. Application of Novel Lateral Tire Force Sensors to Vehicle Parameter Estimation of Electric Vehicles
- Author
-
Kanghyun Nam
- Subjects
lateral tire force sensors ,tire model ,tire cornering stiffness estimation ,lateral vehicle velocity estimation ,ground vehicles ,Chemical technology ,TP1-1185 - Abstract
This article presents methods for estimating lateral vehicle velocity and tire cornering stiffness, which are key parameters in vehicle dynamics control, using lateral tire force measurements. Lateral tire forces acting on each tire are directly measured by load-sensing hub bearings that were invented and further developed by NSK Ltd. For estimating the lateral vehicle velocity, tire force models considering lateral load transfer effects are used, and a recursive least square algorithm is adapted to identify the lateral vehicle velocity as an unknown parameter. Using the estimated lateral vehicle velocity, tire cornering stiffness, which is an important tire parameter dominating the vehicle’s cornering responses, is estimated. For the practical implementation, the cornering stiffness estimation algorithm based on a simple bicycle model is developed and discussed. Finally, proposed estimation algorithms were evaluated using experimental test data.
- Published
- 2015
- Full Text
- View/download PDF
32. Stability Control of Autonomous Ground Vehicles Using Control-Dependent Barrier Functions
- Author
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Yiwen Huang, Yan Chen, and Sze Zheng Yong
- Subjects
Set (abstract data type) ,Vehicle dynamics ,Control and Optimization ,Correctness ,Electronic stability control ,Artificial Intelligence ,Computer science ,Control theory ,Automotive Engineering ,Control (management) ,Stability (learning theory) ,Ground vehicles ,Invariant (computer science) - Abstract
In the development of autonomous ground vehicles (AGVs), guaranteeing vehicle driving safety is a major concern. Among various aspects that need to be thoughtfully considered for driving safety, vehicle stability is one of the most fundamental and important factors. In this paper, to describe a guaranteed vehicle stability control problem, a new time-varying control-dependent invariant set is introduced. Correspondingly, the concept of a time-varying control-dependent barrier function (CDBF) is proposed. The proposed time-varying CDBF is more general than conventional control barrier functions (CBF), since we additionally consider invariant sets that can be time-varying and control-dependent, which will have broader applications. Then, using the proposed framework, we design a vehicle stability control algorithm, which guarantees that the vehicle states are always kept in the time-varying and control-dependent lateral stability regions. Finally, the correctness and effectiveness of the proposed theory and control method are verified and discussed through illustrative simulation results of high-speed J-turn and double lane change maneuvers for an AGV.
- Published
- 2021
33. Continuous‐time receding‐horizon reinforcement learning and its application to path‐tracking control of autonomous ground vehicles
- Author
-
Xin Xu, Yang Lu, Wenzhang Li, and Xinglong Zhang
- Subjects
Control and Optimization ,Horizon (archaeology) ,Control and Systems Engineering ,Computer science ,Control theory ,Applied Mathematics ,Control (management) ,Path tracking ,Reinforcement learning ,Ground vehicles ,Software - Published
- 2021
34. Parametric and Implicit Features-Based UAV–UGVs Time-Varying Formation Tracking: Dynamic Approach
- Author
-
Ahmed Allam, Mohamed Tadjine, and Abdelkrim Nemra
- Subjects
Lyapunov stability ,Control and Optimization ,Control and Systems Engineering ,Control theory ,Computer science ,Control system ,Automotive Engineering ,Mode (statistics) ,Aerospace Engineering ,Robust control ,Ground vehicles ,Tracking (particle physics) ,Parametric statistics - Abstract
Flexible and robust Time-Varying Formation (TVF) tracking of Unmanned Ground Vehicles (UGVs) guided by an Unmanned Aerial Vehicle (UAV) is considered in this paper. The UAV–UGVs system control model is based on leader-follower approach, where the control scheme consists of two consecutive tasks, namely, deployment task and TVF tracking. Accordingly, two novel nonlinear controllers are proposed for controlling the UGVs formation. First, unlike the classical frameworks on UGVs formation tracking, for which only particular shapes are handled (e.g. circle, square, ellipse), we propose a UGVs deployment-controller ensuring to reach free-formation shapes. The key feature is in using the estimated implicit representation of the desired formation shape as a potential function to generate the UGVs reference trajectory. Second, in the TVF tracking task, a robust cascaded velocity/torque controller for UGVs is proposed based on kinematic and dynamic models. Differently from the classical backstepping framework, the key idea is in introducing an auxiliary control input, in such a way that the overall UGV dynamics is converted into a simpler and modular control structure. As such, the auxiliary input is used to control indirectly the actual UGVs velocity vector. A signum term is added to the torque-input to compensate for the unknown external disturbances and unmodeled dynamics. Numerical simulation shows the effectiveness of the proposed formation controllers compared with the case when the perfect velocity-tracking assumption holds. Experimental results are further provided using three festos Robtino robots to show the validity of the proposed TVF tracking velocity-control scheme.
- Published
- 2021
35. Optimal road grade design based on stochastic speed trajectories for minimising transportation energy consumption
- Author
-
Zhiwu Li, Junhui Liu, and Lei Feng
- Subjects
Consumption (economics) ,Transportation energy ,TA1001-1280 ,business.industry ,Mechanical Engineering ,Transportation ,QA75.5-76.95 ,Energy consumption ,Ground vehicles ,Energy engineering ,Automotive engineering ,Transportation engineering ,Electronic computers. Computer science ,Environmental science ,Electricity ,Current (fluid) ,business ,Law ,General Environmental Science ,Transport infrastructure - Abstract
Reducing energy consumption, regardless of fuel or electricity, of ground vehicles is a paramount pursuit in academia and industry. Current research concentrates exclusively on the improvement of the vehicle, but accepts the road conditions as external influences. The innovation of this article is to consider the road conditions, particularly the grade angle, as design variables. It is assumed that the stochastic speed trajectories of all vehicles on the road can be modelled by a Markov chain. The expected value of the average energy consumptions of all vehicles running on the road is defined as the objective function. The optimisation problem is solved by dynamic programming with Markov model. Evaluations have been made on both simulated and measured speed trajectories. For the simulated speed trajectories, the optimal road grade profile designed by the method saves up to 22% energy compared with a flat road. For the measured speed trajectories, the optimal road grade profile saves up to 2.7% transportation energy compared with the actual road profile. Application of this method on building road could lead to considerable energy saving.
- Published
- 2021
36. Path-following enhancement of an 8×8 combat vehicle using active rear axles steering strategies
- Author
-
Haoxiang Lang, Moustafa El-Gindy, and Moataz Ahmed
- Subjects
Axle ,Lateral stability ,Work (electrical) ,Computer science ,Mechanical Engineering ,Path following ,Research studies ,Economic shortage ,Robust control ,Ground vehicles ,Condensed Matter Physics ,Automotive engineering - Abstract
Active rear steering has been used in many research work to enhance ground vehicles’ lateral stability. However, there is a shortage in the published research studies that consider the incorporation of active rear steering for autonomous vehicles applications, especially in case of multi-axle combat vehicles. In this paper, various H∞ controllers are developed to actively steer rear axles of a multi-axle combat vehicle using a linearized bicycle model. The proposed controllers are incorporated with a 22 degrees of Freedom nonlinear Trucksim full vehicle model to study and compare the developed controllers’ performance on a hard surface. Moreover, a frequency-domain analysis is conducted to investigate the influence of the active rear steering on the path-following controllers’ robustness in terms of stability and performance. Three path-following controllers are designed, where the first controller is applied on the front two axles of the vehicle, while the rear two axles are fixed. The second is applied to all-wheel steering vehicle. The third controller is an integration between the designed front steering path-following controller and a developed lateral stability active rear steering controller. Eventually, a series of virtual maneuvers are performed to evaluate the effectiveness of the intended controllers to present the advantages and limitations of each controller at different driving conditions.
- Published
- 2021
37. Communication and Interaction With Semiautonomous Ground Vehicles by Force Control Steering
- Author
-
Tim Smith, Frank Flemisch, Qinggang Meng, Timothy Gordon, Miguel Martinez-Garcia, Roy S. Kalawsky, and Publica
- Subjects
Computer science ,business.industry ,Control (management) ,Stability (learning theory) ,020206 networking & telecommunications ,02 engineering and technology ,Steering wheel ,Ground vehicles ,H670 Robotics and Cybernetics ,Transfer function ,Automation ,Computer Science Applications ,H330 Automotive Engineering ,Human-Computer Interaction ,Control and Systems Engineering ,Control theory ,Steering system ,0202 electrical engineering, electronic engineering, information engineering ,Torque ,020201 artificial intelligence & image processing ,Electrical and Electronic Engineering ,business ,Software ,H660 Control Systems ,Information Systems - Abstract
While full automation of road vehicles remains a future goal, shared-control and semi-autonomous driving – involving transitions of control between the human and the machine – are more feasible objectives in the near term. These alternative driving modes will benefit from new research towards novel steering control devices, more suitable where the machine intelligence controls only partially the vehicle. In this paper it is proposed that when the human shares the control of a vehicle with an autonomous or semi-autonomous system, a force control or non-displacement steering wheel (i.e., a steering wheel which does not rotate but detects the applied torque by the human driver) can be advantageous under certain schemes: tight rein or loose rein modes according to the Hmetaphor. We support this proposition with the first experiments, to the best of our knowledge, in which human participants drove in a simulated road scene with a force control steering wheel. The experiments exhibited that humans can adapt promptly to force control steering and are able to control the vehicle smoothly. Different transfer functions are tested, which translate the applied torque at the force control steering wheel to the steering angle at the wheels of the vehicle; it is shown that fractional order transfer functions increment steering stability and control accuracy when using a force control device. Transition of control experiments are also performed with both, a conventional and a force control steering wheel. This prototypical steering system can be realized via steer-by-wire controls, which are already incorporated in commercially available vehicles.
- Published
- 2021
38. Decentralized Autonomous Navigation of a UAV Network for Road Traffic Monitoring
- Author
-
Chao Huang, Andrey V. Savkin, and Hailong Huang
- Subjects
Scheme (programming language) ,education.field_of_study ,Focus (computing) ,Computer science ,Real-time computing ,Population ,Aerospace Engineering ,ComputerApplications_COMPUTERSINOTHERSYSTEMS ,Ground vehicles ,Electrical and Electronic Engineering ,Surveillance and monitoring ,education ,computer ,Road traffic ,computer.programming_language - Abstract
With the increase of population and the fast growth of private vehicle ownership in urban areas, many roads have become more congested than ever before. The road traffic information plays a crucial role in traffic management. The currently available traffic information collection systems mainly rely on static road-side units, which passively record the traffic information. This article considers an alternative option, i.e., the usage of unmanned aerial vehicles (UAVs) for aerial surveillance, which is more efficient than the conventional ground-based strategies. We focus on deploying a UAV network to monitor the traffic on a road. We propose a decentralized navigation scheme that enables the UAV network to detect blockage and then gather to the blocked area to have better views of the ground vehicles. This scheme only requires the UAVs to share some light measurement information and positions, and it can be implemented in real time.
- Published
- 2021
39. Next-generation NATO reference mobility model complex terramechanics – Part 2: Requirements and prototype
- Author
-
Paramsothy Jayakumar and Tamer M. Wasfy
- Subjects
Mobility model ,Prototype software ,Software ,Computer science ,business.industry ,Mechanical Engineering ,Ground vehicles ,business ,Terramechanics ,Research task ,Finite element method ,Simulation - Abstract
In part 2 of this paper, the Complex Terramechanics (CT) software tools requirements recommended by the NATO research task group RTG-248 are presented along with example simulations from a CT prototype software tool which attempts to satisfy the requirements.
- Published
- 2021
40. Synthetic aperture radar automatic target classification processing concept.
- Author
-
Woollard, M., Bannon, A., Ritchie, M., and Griffiths, H.
- Abstract
A new simulation and processing methodology based on open source tools to produce high fidelity synthetic aperture radar (SAR) simulations of ground vehicles of varying types, as well as analysis of an applied automatic target recognition (ATR) technique is presented in this Letter. This work is based around the RaySAR open‐source model and the outputs have been configured for both monostatic and bistatic geometries. Input CAD models of various military and civilian vehicles are used to produce the SAR imagery. This output imagery was then used to train a tiny you only look once convolutional neural network (CNN) classifier. The classification success of the CNN applied was showed to produce significantly accurate results and the whole pipeline of processing enabled rapid evaluation of potential ATR methods against targets of choice. [ABSTRACT FROM AUTHOR]
- Published
- 2019
- Full Text
- View/download PDF
41. Hybrid architecture for vehicle lateral collision avoidance.
- Author
-
Ariola, Marco, De Tommasi, Gianmaria, Tartaglione, Gaetano, and Amato, Francesco
- Abstract
In this study, the authors consider the problem of collision avoidance of ground vehicles. In this framework, they focus on a single vehicle, and they guarantee that a given safe set is not exited during a mission. More specifically, they consider the yaw‐lateral motion of a two‐wheel vehicle subject to a side wind, and they design a state‐feedback controller such that the vehicle follows the nominal trajectory with a given maximum error. For these purposes, they resort to a control system where a supervisor, implemented as a hybrid automata, decides to switch between two controllers, depending on the measured vehicle lateral displacement from the nominal trajectory. The two controllers are designed using an H∞ approach and the input–output finite‐time stability approach, respectively. Some simulation results are included, showing the effectiveness of the proposed architecture. [ABSTRACT FROM AUTHOR]
- Published
- 2018
- Full Text
- View/download PDF
42. Acoustic Sensors for Air and Surface Navigation Applications.
- Author
-
Kapoor, Rohan, Ramasamy, Subramanian, Gardi, Alessandro, Schyndel, Ron Van, and Sabatini, Roberto
- Subjects
- *
INTELLIGENT transportation systems , *ACOUSTIC transducers , *SATELLITE positioning , *DOPPLER effect , *PREDICTION models - Abstract
This paper presents the state-of-the-art and reviews the state-of-research of acoustic sensors used for a variety of navigation and guidance applications on air and surface vehicles. In particular, this paper focuses on echolocation, which is widely utilized in nature by certain mammals (e.g., cetaceans and bats). Although acoustic sensors have been extensively adopted in various engineering applications, their use in navigation and guidance systems is yet to be fully exploited. This technology has clear potential for applications in air and surface navigation/guidance for intelligent transport systems (ITS), especially considering air and surface operations indoors and in other environments where satellite positioning is not available. Propagation of sound in the atmosphere is discussed in detail, with all potential attenuation sources taken into account. The errors introduced in echolocation measurements due to Doppler, multipath and atmospheric effects are discussed, and an uncertainty analysis method is presented for ranging error budget prediction in acoustic navigation applications. Considering the design challenges associated with monostatic and multi-static sensor implementations and looking at the performance predictions for different possible configurations, acoustic sensors show clear promises in navigation, proximity sensing, as well as obstacle detection and tracking. The integration of acoustic sensors in multi-sensor navigation systems is also considered towards the end of the paper and a low Size, Weight and Power, and Cost (SWaP-C) sensor integration architecture is presented for possible introduction in air and surface navigation systems. [ABSTRACT FROM AUTHOR]
- Published
- 2018
- Full Text
- View/download PDF
43. Extrinsic Parameter Calibration for Line Scanning Cameras on Ground Vehicles with Navigation Systems Using a Calibration Pattern.
- Author
-
Wendel, Alexander and Underwood, James
- Subjects
- *
AUTOMOTIVE navigation systems , *PARAMETER estimation , *CALIBRATION , *PIXELS , *TRIANGULATING manifolds - Abstract
Line scanning cameras, which capture only a single line of pixels, have been increasingly used in ground based mobile or robotic platforms. In applications where it is advantageous to directly georeference the camera data to world coordinates, an accurate estimate of the camera's 6D pose is required. This paper focuses on the common case where a mobile platform is equipped with a rigidly mounted line scanning camera, whose pose is unknown, and a navigation system providing vehicle body pose estimates. We propose a novel method that estimates the camera's pose relative to the navigation system. The approach involves imaging and manually labelling a calibration pattern with distinctly identifiable points, triangulating these points from camera and navigation system data and reprojecting them in order to compute a likelihood, which is maximised to estimate the 6D camera pose. Additionally, a Markov Chain Monte Carlo (MCMC) algorithm is used to estimate the uncertainty of the offset. Tested on two different platforms, the method was able to estimate the pose to within 0.06 m/1.05° and 0.18 m/2.39°. We also propose several approaches to displaying and interpreting the 6D results in a human readable way. [ABSTRACT FROM AUTHOR]
- Published
- 2017
- Full Text
- View/download PDF
44. Lower Extremity Impact and Injury Responses of Male and Female PMHS to High-Rate Vertical Loading
- Author
-
D. Cristino, Warren N Hardy, H. Pietsch, Andrew R. Kemper, John H. Bolte, and Kerry A. Danelson
- Subjects
Orthodontics ,High rate ,Test series ,business.industry ,Biomedical Engineering ,Medicine ,Femur ,Tibia ,Calcaneus ,Kinematics ,Ground vehicles ,business ,Vertical acceleration - Abstract
Whole-body PMHS (Post Mortem Human Surrogate) testing was conducted on the Accelerative Loading Fixture (ALF), which is designed to generate floor and seat loading conditions at the level, rate, location, direction, and extent seen in UBB (Underbody Blast). The overarching goal of this research effort was to examine potential differences in the lower extremity response of females and males under UBB conditions. The ALF consists of an occupant platform that is driven upward by the detonation of an explosive charge. The floor plate undergoes plastic deformation. The occupant platform supports two rigid seats for surrogates. Twenty un-embalmed PMHS were tested, including 50th-percentile males, 75th-percentile females, and 5th-percentile females. Two test series were conducted. Series A had a target floor speed of 8 m/s (2-ms time-to-peak) with a target seat speed of 5 m/s (4-ms time-to-peak). Series B had a target floor speed of 20 m/s (2-ms time-to-peak) with a target seat speed of 4 m/s (7-ms time-to-peak). Major damage occurred to the femur, tibia, fibula, talus, and calcaneus. Lower extremity damage type, incidence, and extent varied between the two sexes. Fifty-percent probability of calcaneus fracture for less than 3-ms time-to-peak is associated with a 781-g peak tibia vertical acceleration for 50th-percentile males, 650-g for 75th-percentile females, and 396-g for 5th-percentile females. Fifty-percent probability of calcaneus fracture, regardless of time-to-peak, is associated with a 368-g peak femur vertical acceleration for 50th-percentile males, 332-g for 75th-percentile females, and 218-g for 5th-percentile females. These results show differences in kinematics and damage outcome between female and male PMHS in UBB conditions. These findings will inform future decisions regarding the requirements for test capabilities that incorporate the female Warfighter. Ultimately, advancements can be made in injury assessment tools such as improved physical surrogates, injury assessment and prediction criteria, modeling and simulation capabilities, test methods, and the optimization of military ground vehicles, personal protective equipment, and injury countermeasures.
- Published
- 2021
45. Simulation of Motion of an Ensemble of Unmanned Ground Vehicles Using FLAME GPU
- Author
-
L. A. Beklaryan, A. L. Beklaryan, F. A. Belousov, Andranik S. Akopov, and Central Economics
- Subjects
Computer science ,business.industry ,Aerospace engineering ,Ground vehicles ,business ,Motion (physics) - Abstract
A new approach to modeling the spatial dynamics of unmanned ground vehicles (UV) and conventional vehicles (CV) using the FLAME GPU supercomputer agent-based simulation platform is presented. A new simulation model of an artificial road network (ARN) of the "Manhattan Grid" type is proposed, within the framework of which the spatial dynamics of the UV and CV ensemble is studied under various scenario conditions. The effects of "turbulence" and "crush" (traffic congestion) resulting from intensive and dense traffic of vehicles are investigated.
- Published
- 2021
46. Integrated navigation of unmanned ground vehicles
- Author
-
Evgeniy Vetoshkin and Il’ya Shipov
- Subjects
Computer science ,General Earth and Planetary Sciences ,Ground vehicles ,Automotive engineering ,General Environmental Science - Abstract
The article considers the experience of creating integrated navigation systems for ground robotic complexes. The main difficulties of choosing the instrument composition and element base in the conditions of domestic industry are outlined. A typical algorithm for prioritizing the initial data for the integrating and generating solutions algorithm for tasks of orientation and determining spatial position is described.
- Published
- 2021
47. Digital sliding mode controllers for active control of ground vehicles
- Author
-
Antonio Navarrete Guzman, Stefano Di Gennaro, Jorge Rivera Dominguez, and Cuauhtémoc Acosta Lúa
- Subjects
Computer Science::Robotics ,Vehicle dynamics ,Control and Systems Engineering ,Computer science ,Control theory ,Discrete time control ,Mode (statistics) ,Ground vehicles ,Tracking (particle physics) ,Active control - Abstract
This paper aims at designing, in the discrete‐time setting and using sliding mode techniques, some controllers ensuring the tracking of desired references of lateral and yaw velocities for...
- Published
- 2021
48. Flexible multi-unmanned ground vehicles (MUGVs) in intersection coordination based on ε-constraint probability collectives algorithm
- Author
-
Alain Quilliot, Lounis Adouane, Zhengze Zhu, Heuristique et Diagnostic des Systèmes Complexes [Compiègne] (Heudiasyc), Université de Technologie de Compiègne (UTC)-Centre National de la Recherche Scientifique (CNRS), Institut Pascal (IP), and SIGMA Clermont (SIGMA Clermont)-Université Clermont Auvergne [2017-2020] (UCA [2017-2020])-Centre National de la Recherche Scientifique (CNRS)
- Subjects
Scheme (programming language) ,Computer science ,02 engineering and technology ,Execution time ,[INFO.INFO-AI]Computer Science [cs]/Artificial Intelligence [cs.AI] ,[SPI.AUTO]Engineering Sciences [physics]/Automatic ,Artificial Intelligence ,[INFO.INFO-AU]Computer Science [cs]/Automatic Control Engineering ,0502 economics and business ,[INFO.INFO-SY]Computer Science [cs]/Systems and Control [cs.SY] ,0202 electrical engineering, electronic engineering, information engineering ,[INFO.INFO-RB]Computer Science [cs]/Robotics [cs.RO] ,ComputingMilieux_MISCELLANEOUS ,Risk management ,computer.programming_language ,050210 logistics & transportation ,Intersection (set theory) ,business.industry ,05 social sciences ,Process (computing) ,Ground vehicles ,Computer Science Applications ,Constraint (information theory) ,Unexpected events ,020201 artificial intelligence & image processing ,business ,Algorithm ,computer - Abstract
Cooperative navigation (CN) is a widespread technique to have efficient navigation of intelligent vehicles. Nonetheless, the CN strategies need to be more consistent in estimating and managing in-road risks. This paper outlines a flexible CN scheme for multiple unmanned ground vehicles (MUGVs) system to deal with such critical cooperative system. With its relative low execution time, the probability collectives (PC) algorithm has succeeded at generating fast and feasible solutions to cross intersections and roundabouts (Philippe et al. 1928–1934, 2019). However, the PC is still sensitive to uncertainty in the navigation process, which highlights the need to adopt several safety margins. This work focuses on balancing between the high-quality cooperative optimization and acceptable computational speed. Thus, a reliable risk management strategy is proposed by introducing a novel e-constraint PC method. A real-time communication mechanism is suggested for a distributed system to avoid invalid behavior due to inconsistency. The novel e-PC based navigation strategy allows the vehicles to adapt their dynamics and react to unexpected events while respecting real-time constraints. One finding appears to be well substantiated by the typical common-yet-difficult scenarios in intensive simulations. The $$\varepsilon$$ -PC method can ensure collision-free behaviors and reserve at least 1.5s of reaction time for vehicles’ safety insurance.
- Published
- 2021
49. Carpe signum: seize the signal – opportunistic navigation with 5G
- Author
-
Kassas, Zak, Kassas, Zak, Abdallah, Ali, Orabi, Mohamad, Kassas, Zak, Kassas, Zak, Abdallah, Ali, and Orabi, Mohamad
- Published
- 2022
50. Review of hybrid electric powered aircraft, its conceptual design and energy management methodologies
- Author
-
Antonios Tsourdos, Ye Xie, Jason Gu, Dan Zhang, and Al Savvarisal
- Subjects
0209 industrial biotechnology ,Aircraft ,Energy management ,Computer science ,Aerospace Engineering ,ComputerApplications_COMPUTERSINOTHERSYSTEMS ,Context (language use) ,02 engineering and technology ,01 natural sciences ,010305 fluids & plasmas ,Hybrid electric propulsion system ,Non-dominated sorting genetic algorithm ,020901 industrial engineering & automation ,Conceptual design ,0103 physical sciences ,Sizing ,Motor vehicles. Aeronautics. Astronautics ,Mechanical Engineering ,TL1-4050 ,Ground vehicles ,Convex optimization ,Fuzzy logic control ,Electrically powered spacecraft propulsion ,Systems engineering ,Hybrid propulsion - Abstract
The paper overviews the state-of-art of aircraft powered by hybrid electric propulsion systems. The research status of the design and energy management of hybrid aircraft and hybrid propulsion systems are further reviewed. The first contribution of the review is to demonstrate that, in the context of relatively underdeveloped electrical storage technologies, the study of mid-scale hybrid aircraft can contribute the most to both theoretical and practical knowledge. Meanwhile, the profits and potential drawbacks of applying hybrid propulsion to mid-scale hybrid airplanes have not been thoroughly illustrated. Secondly, as summed in the overview of design methodologies, the multi-objective optimization transcends the single-objective one. The potential of the hybrid propulsion system can be thoroughly evaluated in only one optimization run, if several objectives optimized simultaneously. Yet there are few researches covering the conceptual design of hybrid aircraft using multi-objective optimization. The review of the most popular energy management strategies discloses the third research gap—current methodologies favoured in hybrid ground vehicles do not consider the aircraft safety. Additionally, both non-causal and causal energy management are needed for performing a complicated flight mission with several sub-tasks.
- Published
- 2021
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