Exploring the Promises and Challenges of Urban Air Mobility (UAM)

This paper is focused on a higher-level report of a new generation of Unmanned Aerial Vehicle (UAV) technologies. Starting from the structural scalability of civil tiltrotors, design strategy and requirements for UAVs, and advanced composite materials, the increased speed and productivity requirements for tiltrotors have spawned several investigations associated with proprotor aero elastic stability augmentation and aerodynamic performance enhancements. The research emphasized the Large Civil Tilt Rotor as the configuration with the best potential to meet the technology goals, and the design, including the challenges of the Large Civil Tilt Rotor (LCTR). The design presented was economically competitive, with the potential for substantial impact on the air transportation system. The research includes some manufacturers of helicopters, drones and tiltrotors carrying out design studies and production of prototypes, as well as research projects aimed at designing, manufacturing, qualifying, and flight-testing the new wing of the Next-Generation Civil Tiltrotor Technology Demonstrator. Promises of Vertical Take-off and Landing (VTOL) aircraft, UAVs, Digitalization of Urban Air Mobility (UAM), and the “U-space” concept are discussed in the paper. The eight SUMP principles and possibilities of future advancements are emphasized.

Reconstructing urban wind flows for urban air mobility using reduced-order data assimilation

Advancements in uncrewed aircrafts and communications technologies have led to a wave of interest and investment in unmanned aircraft systems(UASs)and urban air mobility(UAM)vehicles over the past decade.To support this emerging aviation application,concepts for UAS/UAM traffic management(UTM)systems have been explored.Accurately characterizing and predicting the microscale weather conditions,winds in particular,will be critical to safe and efficient operations of the small UASs/UAM aircrafts within the UTM.This study implements a reduced order data assimilation approach to reduce discrepancies between the predicted urban wind speed with computational fluid dynamics(CFD)Reynolds-averaged Navier Stokes(RANS)model with real-world,limited and sparse observations.The developed data assimilation system is UrbanDA.These observations are simulated using a large eddy simulation(LES).The data assimilation approach is based on the time-independent variational framework and uses space reduction to reduce the memory cost of the process.This approach leads to error reduction throughout the simulated domain and the reconstructed field is different than the initial guess by ingesting wind speeds at sensor locations and hence taking into account flow unsteadiness in a time when only the mean flow quantities are resolved.Different locations where wind sensors can be installed are discussed in terms of their impact on the resulting wind field.It is shown that near-wall locations,near turbulence generation areas with high wind speeds have the highest impact.Approximating the model error with its principal mode provides a better agreement with the truth and the hazardous areas for UAS navigation increases by more than 10%as wind hazards resulting from buildings wakes are better simulated through this process.

A demand forecasting model for urban air mobility in Chengdu,China

The successful application of new technologies such as remotely piloted aircraft systems,distributed electric propulsion systems,and automatic control systems on electric vertical take-off and landing(eVTOL)aircraft has prompted Urban Air Mobility(UAM)to be mentioned frequently.UAM is a newly raised transport mode of using eVTOL aircraft to transport people and cargo in urban areas,which is thought to share some of the traffic on the ground.One of the prerequisites for UAM to operate on a regular basis is that its demand can support the operating costs,so forecasting UAM demand is necessary.We conduct UAM demand forecasting based on the four-step method,focusing on improving the third-step modal split,and propose a demand forecasting model based on the logit model.The model combines a nested logit(NL)model with a multinomial logit(MNL)model to solve the problem of non-existent UAM sharing rates.We use Chengdu,China as an example,and focus on forecasting the UAM traffic demand in 2030 with the help of the four-step method.The results show that UAM is suitable for shared operation during the early stages.With a fully shared operation,the UAM share rate increases by 0.73%for every kilometer increase in distance.Moreover,UAM is more competitive than other modes for delivery distances exceeding 15 km.Finally,using the distributions of the share rate and traffic flow pattern from the simulation,we propose the routes that can be prioritized for UAM operations in Chengdu.

Overall eVTOL aircraft design for urban air mobility

Electric vertical takeoff and landing(eVTOL)aircraft have emerged as a potential alternative to the existing transportation system,offering a transition from two-dimensional commuting and logistics to three-dimensional mobility.As a groundbreaking innovation in both the automotive and aviation sectors,eVTOL holds significant promise but also presents notable challenges.This paper aims to address the overall aircraft design(OAD)approach specifically tailored for eVTOL in the context of Urban Air Mobility(UAM).In contrast to traditional OAD methods,this study introduces and integrates disciplinary methodologies specifically catered to eVTOL aircraft design.A case study is conducted on a tilt-duct eVTOL aircraft with a typical UAM mission,and the disciplinary performance,including initial sizing,aerodynamics,electric propulsion systems,stability and control,weight,mission analysis and noise,is examined using the OAD methodologies.The findings demonstrate that the current approach effectively evaluates the fundamental aircraft-level performance of eVTOL,albeit further high-fidelity disciplinary analysis and optimization methods are required for future MDO-based eVTOL overall aircraft design.

When Air Quality Becomes Deleterious—A Case Study for Kigali, Rwanda

Rwanda is a landlocked republic in Equatorial Africa. The capital Kigali (1°57'S, 30°04'E) can be mentioned as a typical African city due to its rising population and the rising rate of motorization. Different pollutants produced e.g. by a highusage rate of mopeds or open fireplaces burning wood for cooking and household chores could be detected. Climatological parameters as well as air pollutants were measured within the urban area. Additionally, highly frequented spatial and temporal mobile measurements of particulate matter were taken during different dry seasons regarding different conditions. These values indicated an urban heat island, which tended to rise for the last four decades. A temporary phenomenon for the air pollution indicators is visible during clear and calm weather situations, e.g. the distinctive relief caused an accumulation within small valleys called “Marais” in the night time. Unfortunately, these are the favourite places for living and agriculture. So there is no infrequence in values of PM10 > 1.000 μg·m-3. The origin of the different airborne particles was verified by using a scanning electron microscope and it could be mentioned that most particles were from the combustion of biomass and traffic.

Retarded Harrier Maneuver as a New and Efficient Approach for Fixed-Wing Aircraft to Achieve S/VTOL

Modern day VTOL fixed-wing aircraft based on quadplane design is relatively simple and reliable due to lack of complex mechanical components compared to tilt-wings or tilt-rotors in the pre-80’s era. Radio-controlled aerobatic airplanes have thrust-to-weight ratio of greater than unity and are capable of performing a range of impressive maneuvers including the so-called harrier maneuver. We hereby present a new maneuver known as the retarded harrier that is applicable to un/manned fixed-wing aircraft for achieving VTOL flight with a better forward flight performance than a quadplane in terms of weight, speed and esthetics. An airplane with tandem roto-stabilizers is also presented as an efficient airframe to achieve VTOL via retarded harrier maneuver, and detailed analysis is given for hovering at 45° and 60° and comparison is made against the widely adopted quadplane. This work also includes experimental demonstration of retarded harrier maneuver using a small remotely pilot airplane of wingspan 650 mm.

面向预期功能安全的eVTOL智能避障系统运行时保证方法

为保障电动垂直起降飞行器(eVTOL)在城市空中交通(UAM)场景下的预期功能安全(SOTIF),降低人工智能算法的验证难度,建立基于运行时保证(RTA)方法的避障模型。首先,使用人工势场法改进的柔性动作评价(SAC)算法作为eVTOL智能避障系统的复杂功能;然后,使用动态反应规划(DRP)作为智能航电系统的备用功能,以减缓SOTIF危险,同时,使用监视和决策模块采集环境状态,搭建RTA架构;最后,分别仿真仅使用复杂功能和具有RTA架构的避障系统,对比避障效果。结果表明:2种方法均可实现避障,但仅使用复杂功能的传统避障系统会带来SOTIF危险;经过RTA架构设计,可使eVTOL的安全飞行时长占比由78.4%提高到98.15%,总航路长度仅增加0.95%,在保障效率的同时,降低了在运行场景中的风险。

城市空中交通创新生态系统构建及运行机制

基于城市空中交通(UAM)的研究现状,进一步引入创新生态系统理论,探索UAM创新生态系统的构成要素,深入剖析参与主体、外部环境和系统资源如何实现良性发展。研究结果表明,UAM创新生态系统由“技术-应用-商业”主体系统和环境系统构成;在政策引领机制、技术驱动机制、场景驱动机制、金融支持机制驱动下,从政府、技术和应用场景层面提出建议,促进UAM创新生态系统持续发展。研究结果为发展UAM创新生态系统、完善低空经济产业生态和创新UAM相关企业商业模式提供管理启示,为未来智慧城市建设发展提供新方向。

基于通信信号管制的城市空中交叉口设计研究

为确保城市低空空域内无人机规模化运行安全,缓解低空交通运行瓶颈,本文借鉴地面交通较为成熟的研究成果,结合城市低空及无人机运行特色,提出一种基于通信信号管制的城市空中交叉口设计模型。首先,考虑航路构型设计与航路运行主体,构建无人机运行所需的城市低空航路。其次,从进出口道、冲突响应距离2方面对空中交叉口几何结构进行设计,再从进口航道划分、通信信号管制、无人机高度调整3方面对交通组织进行设计,实现对空中交叉口的基本模型设计。最后,设置仿真实验验证该模型的可行性,并分析不同参数组合下的交叉口综合通行效率。实验结果表明:当飞行速度为18 m/s,纵向间隔为50 m,管制信号周期时长为226 s时,综合通行效率达到最佳。本研究可为未来城市空中交通航路网络精细划设与管理提供支撑,增强低空无人机交通的实践性。

城市低空空中交通及无人机路径规划研究综述

随着城市交通拥堵的日益严重和社会的智能化发展,城市空中交通(UAM)的概念逐步形成。近年来,电动垂直起降(eVTOL)航空器发挥着越来越重要的作用,无人驾驶航空器(简称无人机)在城市低空空域的运行应受到更加有序的管理。简要概述了城市空中交通的基本概念及国内外的发展和应用现状。分别概述了城市低空空域设计概念、城市低空航路规划和城市低空无人机路径规划方法。结合国内外研究现状,从不同方面提出了城市低空空中交通研究展望。

A reinforcement learning approach to vehicle coordination for structured advanced air mobility

Advanced Air Mobility(AAM)has emerged as a pioneering concept designed to optimize the efficacy and ecological sustainability of air transportation.Its core objective is to provide highly automated air transportation services for passengers or cargo,operating at low altitudes within urban,suburban,and rural regions.AAM seeks to enhance the efficiency and environmental viability of the aviation sector by revolutionizing the way air travel is conducted.In a complex aviation environment,traffic management and control are essential technologies for safe and effective AAM operations.One of the most difficult obstacles in the envisioned AAM systems is vehicle coordination at merging points and intersections.The escalating demand for air mobility services,particularly within urban areas,poses significant complexities to the execution of such missions.In this study,we propose a novel multi-agent reinforcement learning(MARL)approach to efficiently manage high-density AAM operations in structured airspace.Our approach provides effective guidance to AAM vehicles,ensuring conflict avoidance,mitigating traffic congestion,reducing travel time,and maintaining safe separation.Specifically,intelligent learning-based algorithms are developed to provide speed guidance for each AAM vehicle,ensuring secure merging into air corridors and safe passage through intersections.To validate the effectiveness of our proposed model,we conduct training and evaluation using BlueSky,an open-source air traffic control simulation environment.Through the simulation of thousands of aircraft and the integration of real-world data,our study demonstrates the promising potential of MARL in enabling safe and efficient AAM operations.The simulation results validate the efficacy of our approach and its ability to achieve the desired outcomes.

粤港澳大湾区城市空中交通高质量发展的探索及其研究

粤港澳大湾区交通体系建设在区域发展中起着决定性作用,在着力发展铁路、公路、海运、河运和传统运输航空的同时,如何针对区域需求发展更高质量的交通方式是区域交通整体筹划的题中之义。电动垂直起降(EVTOL)是航空器制造业领域一场重大技术革命,它使城市空中交通(Urban Air Mobility,UAM)从梦想走向现实。长期以来,城市空中交通以直升机为主,但出于成本高、噪声大、污染重和对环境要求高等原因,其发展规模非常小,没有受到人们关注。近年来EVTOL技术快速发展,万亿“蓝海”赛道雏形日益清晰,各国竞争开始加剧。粤港澳大湾区具有天然发展UAM的基础、条件和环境,发展的成效对湾区整体水平又有重要价值。面对这一全新课题,本文从必要性、可行性出发,研究其价值所在,提出发展思路和路径,对存在的问题进行简要剖析并给出解决对策,期望对UAM的发展有所帮助。

复杂网络城市空中交通生态下eVTOL运行风险演化分析

为明确城市空中交通(UAM)生态下电动垂直起降飞行器(eVTOL)风险因素间的关联性,并探究各类风险因素对风险防控的影响,采用复杂网络理论建立风险演化模型,以国内外无人机事故数据库和通用航空事故统计结果为基础,结合eVTOL在城市低空场景下的运行特点,从人-机-环角度确定35类风险因素和10类危险事件;采用Gephi软件构建网络模型,采用节点度、接近度中心性、介数中心性与网页排序(PR)算法综合评估关键节点,采用边介数评估关键边,确定关键风险传播路径;以降低系统风险为目标,提出断链减灾措施,通过网络效率指标衡量断链控制后的系统安全性。研究结果表明:UAM生态下,eVTOL风险因素关联性较强,且存在8条关键风险传播链。阻断关键人为因素、关键系统技术故障因素及关键中间危险事件3种断链方案,分别使系统安全性提高4.74%、16.21%、18.10%。

城市低空出行工具的MBSE开发框架研究

城市低空出行工具(UAM)开发目前处于早期阶段,作为一种复杂的新系统,UAM开发需要一套完整、科学的开发框架。提出了一种MBSE开发框架,对UAM的开发流程进行详细的分析和设计。该MBSE开发框架基于MBSE方法论从人—机—环的视角进行UAM的利益相关方识别、使用场景的识别定义,并采用建模的方法完成UAM的能力开发,最后按照体系架构设计的思想使用模型在环仿真和人在环仿真试验对UAM概念阶段的设计进行测试与验证。该MBSE开发框架在数字域闭环UAM的需求、设计、验证,大部分设计缺陷在数字方案阶段被发现解决,能够提高产品开发效率、降低开发风险、提高产品质量,对新型复杂产品开发具备一定的指导价值。

飞行汽车的研究发展与关键技术

飞行汽车作为面向城市空中交通和未来出行的新型交通工具,正日益受到汽车和航空领域的重视,成为汽车和航空技术与产业跨界融合的重要发展趋势。该文介绍了飞行汽车的内涵及城市空中交通(UAM)概念的兴起,阐述了飞行汽车早期梦想的探索历程、面向城市空中交通的研究现状,以及未来将在全新智慧出行交通体系下实现大众化汽车“飞”起来的发展趋势;论述了飞行汽车发展的高功率密度电动推进、高升阻比轻质车体和低空飞行智能驾驶等主要性能瓶颈和关键技术;提出了中国飞行汽车的阶段性发展目标和构建汽车与航空跨界融合技术创新体系,以及重点推动城市空中交通和应急救援等领域示范应用的发展建议。

城市交通与机动车排放控制

论述了随着城市机动车保有量的急剧增长,机动车排放污染物对城市大气环境的影响也越来越大。分析了城市机动车排放污染的状况及影响因素,特别重点讨论了机动车车型和汽车城市道路运行工况对机动车排放污染物的影响。为了改善城市大气环境,推动城市全面、协调、可持续发展,提出了若干措施,供城市规划、城市交通管理部门参考。

Urban air mobility(UAM)and ground transportation integration:A survey

This study explores urban air mobility(UAM)as a strategy for mitigating escalating traffic congestion in major urban areas as a consequence of a static transportation supply versus dynamic demand growth.It offers an indepth overview of UAM development,highlighting its present state and the challenges of integration with established urban transport systems.Key areas of focus include the technological advancements and obstacles in electric vertical take-off and landing(eVTOL)aircrafts,which are essential for UAM operation in urban environments.Furthermore,it explores the infrastructure requirements for UAM,including vertiport deployment and the creation of adept air traffic control(ATC)systems.These developments must be integrated into the urban landscape without exacerbating land-use challenges.This paper also examines the regulatory framework for UAM,including existing aviation regulations and the necessity for novel policies specifically designed for urban aerial transport.This study presents a comprehensive perspective for various stakeholders,from policymakers to urban planners,highlighting the need for a thorough understanding of UAM’s potential and effective assimilation into urban mobility frameworks.

面向城市空中交通的eVTOL飞行器路径规划算法对比

随着城市空中交通(UAM)迅速发展,为实现eVTOL飞行器在城市低空空域高效安全运行,解决其路径规划面临的空域复杂多变、障碍物繁杂、低空飞行、噪声和气象等问题,从而推动城市空中出行时代的快速到来,文章引入AirMatrix空域规划概念作为城市低空空域规划方案,并针对eVTOL的城市低空运行特点对AirMatrix空域作了四维区块化分割,结合这一空域规划方案,选取了快速搜索随机树(RRT)算法、改进A^(*)算法和粒子群算法(PSO)算法进行了综合分析和三维地形中的仿真验证,其结果表明:RRT算法搜索速率最快;改进A^(*)算法具有最好的路径规划质量;PSO算法在路径规划长度和搜索速度两方面均有所欠缺。改进A^(*)算法相对RRT算法和PSO算法更适用于低密度城市空域路径规划。

车载PM_(2.5)移动监测平台助力城市空气质量精细化管理

在污染防治被列为国家三大攻坚战之一、蓝天保卫战成为未来生态城市建设、改善民生(居住环境)的重点任务背景下,本文介绍了作者团队研发的以城市出租车为载体,以城市空气质量管控为目的、可实现空间颗粒度高、时间响应快的时空高分辨率移动监测系统。该系统融合先进的传感器物联技术、云计算技术,以低成本和高速响应的优势弥补了既有的国家环境监控站标准仪器监测系统(以下简称“国控站”)“成本高、颗粒度稀疏、响应慢”的短板,填补了监测盲区,增强了动态响应,构筑起更加精细、完整的城市监控网络,也是大数据、物联网科技发展背景下对智慧城市发展需求的积极响应。该模式已经在全国十余座城市展开应用,取得了显著的环保和社会效益。

宜宾市2018年移动源污染物排放清单与空间分布特征

移动源已成为城市大气污染的主要贡献源。基于MOVES模型和地理信息系统(ArcGIS)技术,建立了宜宾市2018年分辨率为2 km×2 km的移动源网格化排放清单。研究结果表明:宜宾市2018年移动源污染物碳氢化合物(THC)、CO、NOX、PM_(2.5)、PM_(10)、NH_(3)、SO_(2)和挥发性有机化合物(VOC)的年排放量依次为0.33×10^(4)t、3.53×10^(4)t、1.29×10^(4)t、0.56×10^(3)t、0.59×10^(3)t、0.16×10^(3)t、0.98×10^(3)t和1.82×10^(3)t。摩托车和出租车是THC的主要贡献源,摩托车和小型客车是CO的主要贡献者,非道路移动机械和重型货车是NOX、PM_(2.5)和PM_(10)的主要贡献源。THC和CO主要来自于道路国Ⅲ标准移动源,NO_(X)、PM_(2.5)、PM_(10)、NH_(3)和SO_(2)则主要来自于道路国Ⅳ标准移动源。