自动无人驾驶飞行器(UAV)惯性导航呈现极端依赖性依赖全球导航卫星系统(GNSS)信号的可用性,而无论哪种慢于但不可避免的位置漂移,如果GNSS可能最终可能导致平台的损失信号未恢复,或者飞机没有达到可以通过遥控器恢复的位置。本文介绍了一种随机的高度高保真仿真,其湍流和不同天气在旨在测试和验证不同导航算法的GNSS拒绝性能的湍流和不同的天气中的固定机翼低交换(尺寸,重量和电源)自主无人机的飞行。它的开源\ nm {\ cc}实施已发布并公开可用。板载传感器包括加速度计,陀螺仪,磁力计,皮革管,空气数据系统,GNSS接收器和数码相机,因此模拟对于惯性,视觉和视觉惯性导航系统有效。考虑了涉及GNSS信号丢失的两种情景:第一个代表了在经历不同的天气时将特派团和前往远程恢复位置中止的使命和前进所涉及的挑战,而第二种模型基于一系列紧密间隔的轴承继续执行任务变化。所有仿真模块都已以尽可能少的简化模拟,以增加结果的现实。虽然飞机表演的实施及其控制系统是确定性的,但是所有其他模块的实施方式,包括使命,传感器,天气,风,湍流和初始估计是完全随机的。这使得通过依赖于这两种情况的大量执行的Monte-Carlo模拟,可以实现每个提出的导航系统的鲁棒评估。
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This article proposes a method to diminish the pose (position plus attitude) drift experienced by an SVO (Semi-Direct Visual Odometry) based visual navigation system installed onboard a UAV (Unmanned Air Vehicle) by supplementing its pose estimation non linear optimizations with priors based on the outputs of a GNSS (Global Navigation Satellite System) Denied inertial navigation system. The method is inspired in a PI (Proportional Integral) control system, in which the attitude, altitude, and rate of climb inertial outputs act as targets to ensure that the visual estimations do not deviate far from their inertial counterparts. The resulting IA-VNS (Inertially Assisted Visual Navigation System) achieves major reductions in the horizontal position drift inherent to the GNSS-Denied navigation of autonomous fixed wing low SWaP (Size, Weight, and Power) UAVs. Additionally, the IA-VNS can be considered as a virtual incremental position (ground velocity) sensor capable of providing observations to the inertial filter. Stochastic high fidelity Monte Carlo simulations of two representative scenarios involving the loss of GNSS signals are employed to evaluate the results and to analyze their sensitivity to the terrain type overflown by the aircraft as well as to the quality of the onboard sensors on which the priors are based. The author releases the C ++ implementation of both the navigation algorithms and the high fidelity simulation as open-source software.
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自主飞机的导航系统依赖于由套件的读数提供的读数来估计飞机状态。在固定翼车的情况下,传感器套件由三联脉的加速度计,陀螺仪和磁力计,全球导航卫星系统(GNSS)接收器和空中数据系统(皮托管,空气叶片,温度计和晴雨表)组成,并且通常由一个或多个数码相机补充。准确表示每个传感器的行为和错误源,以及摄像机生成的图像,在飞行模拟中是必不可少的,以及对新型惯性或视觉导航算法的评估,以及在低交换的情况下大小,重量和电源)飞机,其中传感器的质量和价格有限。本文为每个传感器提供了现实和可定制的模型,该传感器已被实现为开源C ++模拟。随着时间的推移提供了飞机状态的真正变化,模拟提供了所有传感器产生的误差的时间戳系列,以及地球表面的现实图像,类似于沿着指示的状态位置飞行的真正摄像机飞行的地面表面和态度。
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安装在微空中车辆(MAV)上的地面穿透雷达是有助于协助人道主义陆地间隙的工具。然而,合成孔径雷达图像的质量取决于雷达天线的准确和精确运动估计以及与MAV产生信息性的观点。本文介绍了一个完整的自动空气缩进的合成孔径雷达(GPSAR)系统。该系统由空间校准和时间上同步的工业级传感器套件组成,使得在地面上方,雷达成像和光学成像。自定义任务规划框架允许在地上控制地上的Stripmap和圆形(GPSAR)轨迹的生成和自动执行,以及空中成像调查飞行。基于因子图基于Dual接收机实时运动(RTK)全局导航卫星系统(GNSS)和惯性测量单元(IMU)的测量值,以获得精确,高速平台位置和方向。地面真理实验表明,传感器时机为0.8美元,正如0.1美元的那样,定位率为1 kHz。与具有不确定标题初始化的单个位置因子相比,双位置因子配方可提高高达40%,批量定位精度高达59%。我们的现场试验验证了本地化准确性和精度,使得能够相干雷达测量和检测在沙子中埋入的雷达目标。这验证了作为鸟瞰着地图检测系统的潜力。
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在过去的十年中,自动驾驶航空运输车辆引起了重大兴趣。这是通过空中操纵器和新颖的握手的技术进步来实现这一目标的。此外,改进的控制方案和车辆动力学能够更好地对有效载荷进行建模和改进的感知算法,以检测无人机(UAV)环境中的关键特征。在这项调查中,对自动空中递送车辆的技术进步和开放研究问题进行了系统的审查。首先,详细讨论了各种类型的操纵器和握手,以及动态建模和控制方法。然后,讨论了降落在静态和动态平台上的。随后,诸如天气状况,州估计和避免碰撞之类的风险以确保安全过境。最后,调查了交付的UAV路由,该路由将主题分为两个领域:无人机操作和无人机合作操作。
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Developing and testing algorithms for autonomous vehicles in real world is an expensive and time consuming process. Also, in order to utilize recent advances in machine intelligence and deep learning we need to collect a large amount of annotated training data in a variety of conditions and environments. We present a new simulator built on Unreal Engine that offers physically and visually realistic simulations for both of these goals. Our simulator includes a physics engine that can operate at a high frequency for real-time hardware-in-the-loop (HITL) simulations with support for popular protocols (e.g. MavLink). The simulator is designed from the ground up to be extensible to accommodate new types of vehicles, hardware platforms and software protocols. In addition, the modular design enables various components to be easily usable independently in other projects. We demonstrate the simulator by first implementing a quadrotor as an autonomous vehicle and then experimentally comparing the software components with real-world flights.
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滑动检测对于在外星人表面驾驶的流浪者的安全性和效率至关重要。当前的行星流动站滑移检测系统依赖于视觉感知,假设可以在环境中获得足够的视觉特征。然而,基于视觉的方法容易受到感知降解的行星环境,具有主要低地形特征,例如岩石岩,冰川地形,盐散发物以及较差的照明条件,例如黑暗的洞穴和永久阴影区域。仅依靠视觉传感器进行滑动检测也需要额外的计算功率,并降低了流动站的遍历速率。本文回答了如何检测行星漫游者的车轮滑移而不取决于视觉感知的问题。在这方面,我们提出了一个滑动检测系统,该系统从本体感受的本地化框架中获取信息,该框架能够提供数百米的可靠,连续和计算有效的状态估计。这是通过使用零速度更新,零角度更新和非独立限制作为惯性导航系统框架的伪测量更新来完成的。对所提出的方法进行了对实际硬件的评估,并在行星 - 分析环境中进行了现场测试。该方法仅使用IMU和车轮编码器就可以达到150 m左右的92%滑动检测精度。
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The performance of inertial navigation systems is largely dependent on the stable flow of external measurements and information to guarantee continuous filter updates and bind the inertial solution drift. Platforms in different operational environments may be prevented at some point from receiving external measurements, thus exposing their navigation solution to drift. Over the years, a wide variety of works have been proposed to overcome this shortcoming, by exploiting knowledge of the system current conditions and turning it into an applicable source of information to update the navigation filter. This paper aims to provide an extensive survey of information aided navigation, broadly classified into direct, indirect, and model aiding. Each approach is described by the notable works that implemented its concept, use cases, relevant state updates, and their corresponding measurement models. By matching the appropriate constraint to a given scenario, one will be able to improve the navigation solution accuracy, compensate for the lost information, and uncover certain internal states, that would otherwise remain unobservable.
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我们提出了通过现实的模拟和现实世界实验来支持可复制研究的多运动无人机控制(UAV)和估计系统。我们提出了一个独特的多帧本地化范式,用于同时使用多个传感器同时估算各种参考框架中的无人机状态。该系统可以在GNSS和GNSS贬低的环境中进行复杂的任务,包括室外室内过渡和执行冗余估计器,以备份不可靠的本地化源。提出了两种反馈控制设计:一个用于精确和激进的操作,另一个用于稳定和平稳的飞行,并进行嘈杂的状态估计。拟议的控制和估计管道是在3D中使用Euler/Tait-Bryan角度表示的,而无需使用Euler/Tait-Bryan角度表示。取而代之的是,我们依靠旋转矩阵和一个新颖的基于标题的惯例来代表标准多电流直升机3D中的一个自由旋转自由度。我们提供了积极维护且有据可查的开源实现,包括对无人机,传感器和本地化系统的现实模拟。拟议的系统是多年应用系统,空中群,空中操纵,运动计划和遥感的多年研究产物。我们所有的结果都得到了现实世界中的部署的支持,该系统部署将系统塑造成此处介绍的表单。此外,该系统是在我们团队从布拉格的CTU参与期间使用的,该系统在享有声望的MBZIRC 2017和2020 Robotics竞赛中,还参加了DARPA SubT挑战赛。每次,我们的团队都能在世界各地最好的竞争对手中获得最高位置。在每种情况下,挑战都促使团队改善系统,并在紧迫的期限内获得大量高质量的体验。
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We designed and constructed an A-sized base autonomous underwater vehicle (AUV), augmented with a stack of modular and extendable hardware and software, including autonomy, navigation, control and high fidelity simulation capabilities (A-size stands for the standard sonobuoy form factor, with a maximum diameter of 124 mm). Subsequently, we extended this base vehicle with a novel tuna-inspired morphing fin payload module (referred to as the Morpheus AUV), to achieve good directional stability and exceptional maneuverability; properties that are highly desirable for rigid hull AUVs, but are presently difficult to achieve because they impose contradictory requirements. The morphing fin payload allows the base AUV to dynamically change its stability-maneuverability qualities by using morphing fins, which can be deployed, deflected and retracted, as needed. The base vehicle and Morpheus AUV were both extensively field tested in-water in the Charles river, Massachusetts, USA; by conducting hundreds of hours of operations over a period of two years. The maneuvering capability of the Morpheus AUV was evaluated with and without the use of morphing fins to quantify the performance improvement. The Morpheus AUV was able to showcase an exceptional turning rate of around 25-35 deg/s. A maximum turn rate improvement of around 35% - 50% was gained through the use of morphing fins.
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本文提出了一种新颖的方法,用于在具有复杂拓扑结构的地下领域的搜索和救援行动中自动合作。作为CTU-Cras-Norlab团队的一部分,拟议的系统在DARPA SubT决赛的虚拟轨道中排名第二。与专门为虚拟轨道开发的获奖解决方案相反,该建议的解决方案也被证明是在现实世界竞争极为严峻和狭窄的环境中飞行的机上实体无人机的强大系统。提出的方法可以使无缝模拟转移的无人机团队完全自主和分散的部署,并证明了其优于不同环境可飞行空间的移动UGV团队的优势。该论文的主要贡献存在于映射和导航管道中。映射方法采用新颖的地图表示形式 - 用于有效的风险意识长距离计划,面向覆盖范围和压缩的拓扑范围的LTVMAP领域,以允许在低频道通信下进行多机器人合作。这些表示形式与新的方法一起在导航中使用,以在一般的3D环境中可见性受限的知情搜索,而对环境结构没有任何假设,同时将深度探索与传感器覆盖的剥削保持平衡。所提出的解决方案还包括一条视觉感知管道,用于在没有专用GPU的情况下在5 Hz处进行四个RGB流中感兴趣的对象的板上检测和定位。除了参与DARPA SubT外,在定性和定量评估的各种环境中,在不同的环境中进行了广泛的实验验证,UAV系统的性能得到了支持。
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本文提出了一项新颖的控制法,以使用尾随机翼无人驾驶飞机(UAV)进行准确跟踪敏捷轨迹,该轨道在垂直起飞和降落(VTOL)和向前飞行之间过渡。全球控制配方可以在整个飞行信封中进行操作,包括与Sideslip的不协调的飞行。显示了具有简化空气动力学模型的非线性尾尾动力学的差异平坦度。使用扁平度变换,提出的控制器结合了位置参考的跟踪及其导数速度,加速度和混蛋以及偏航参考和偏航速率。通过角速度进纸术语包含混蛋和偏航率参考,可以改善随着快速变化的加速度跟踪轨迹。控制器不取决于广泛的空气动力学建模,而是使用增量非线性动态反演(INDI)仅基于局部输入输出关系来计算控制更新,从而导致对简化空气动力学方程中差异的稳健性。非线性输入输出关系的精确反转是通过派生的平坦变换实现的。在飞行测试中对所得的控制算法进行了广泛的评估,在该测试中,它展示了准确的轨迹跟踪和挑战性敏捷操作,例如侧向飞行和转弯时的侵略性过渡。
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We address the theoretical and practical problems related to the trajectory generation and tracking control of tail-sitter UAVs. Theoretically, we focus on the differential flatness property with full exploitation of actual UAV aerodynamic models, which lays a foundation for generating dynamically feasible trajectory and achieving high-performance tracking control. We have found that a tail-sitter is differentially flat with accurate aerodynamic models within the entire flight envelope, by specifying coordinate flight condition and choosing the vehicle position as the flat output. This fundamental property allows us to fully exploit the high-fidelity aerodynamic models in the trajectory planning and tracking control to achieve accurate tail-sitter flights. Particularly, an optimization-based trajectory planner for tail-sitters is proposed to design high-quality, smooth trajectories with consideration of kinodynamic constraints, singularity-free constraints and actuator saturation. The planned trajectory of flat output is transformed to state trajectory in real-time with consideration of wind in environments. To track the state trajectory, a global, singularity-free, and minimally-parameterized on-manifold MPC is developed, which fully leverages the accurate aerodynamic model to achieve high-accuracy trajectory tracking within the whole flight envelope. The effectiveness of the proposed framework is demonstrated through extensive real-world experiments in both indoor and outdoor field tests, including agile SE(3) flight through consecutive narrow windows requiring specific attitude and with speed up to 10m/s, typical tail-sitter maneuvers (transition, level flight and loiter) with speed up to 20m/s, and extremely aggressive aerobatic maneuvers (Wingover, Loop, Vertical Eight and Cuban Eight) with acceleration up to 2.5g.
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微空中车辆(MAVS)在户外操作的限制靠近障碍物,通过他们承受风阵风的能力。目前广泛的位置控制方法,例如比例整体衍生物控制在阵风的影响下不会均匀。增量非线性动态反转(INDI)是一种基于传感器的控制技术,可以控制受扰动的非线性系统。它是为载人飞机或MAVS的态度控制而开发的。在本文中,我们将这种方法概括为严重燃烧负载下MAV的外环控制。在一个实验中对传统的比例积分衍生物(PID)控制器的显着改进进行了说明,其中四轮电机在10米/秒的吹风机排气进出中。控制方法不依赖于频繁的位置更新,如使用标准GPS模块的外部实验中所示。最后,我们研究了使用线性化来计算推力向量增量的效果,与非线性计算相比。该方法需要很少的建模并且是计算效率。
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The field of autonomous mobile robots has undergone dramatic advancements over the past decades. Despite achieving important milestones, several challenges are yet to be addressed. Aggregating the achievements of the robotic community as survey papers is vital to keep the track of current state-of-the-art and the challenges that must be tackled in the future. This paper tries to provide a comprehensive review of autonomous mobile robots covering topics such as sensor types, mobile robot platforms, simulation tools, path planning and following, sensor fusion methods, obstacle avoidance, and SLAM. The urge to present a survey paper is twofold. First, autonomous navigation field evolves fast so writing survey papers regularly is crucial to keep the research community well-aware of the current status of this field. Second, deep learning methods have revolutionized many fields including autonomous navigation. Therefore, it is necessary to give an appropriate treatment of the role of deep learning in autonomous navigation as well which is covered in this paper. Future works and research gaps will also be discussed.
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自动化驾驶系统(广告)开辟了汽车行业的新领域,为未来的运输提供了更高的效率和舒适体验的新可能性。然而,在恶劣天气条件下的自主驾驶已经存在,使自动车辆(AVS)长时间保持自主车辆(AVS)或更高的自主权。本文评估了天气在分析和统计方式中为广告传感器带来的影响和挑战,并对恶劣天气条件进行了解决方案。彻底报道了关于对每种天气的感知增强的最先进技术。外部辅助解决方案如V2X技术,当前可用的数据集,模拟器和天气腔室的实验设施中的天气条件覆盖范围明显。通过指出各种主要天气问题,自主驾驶场目前正在面临,近年来审查硬件和计算机科学解决方案,这项调查概述了在不利的天气驾驶条件方面的障碍和方向的障碍和方向。
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森林中自主冬季导航所固有的挑战包括缺乏可靠的全球导航卫星系统(GNSS)信号,低特征对比度,高照明变化和变化环境。这种类型的越野环境是一个极端的情况,自治车可能会在北部地区遇到。因此,了解对自动导航系统对这种恶劣环境的影响非常重要。为此,我们介绍了一个现场报告分析亚曲率区域中的教导和重复导航,同时受到气象条件的大变化。首先,我们描述了系统,它依赖于点云注册来通过北方林地定位移动机器人,同时构建地图。我们通过在教学和重复模式下在自动导航中进行了在实验中评估了该系统。我们展示了密集的植被扰乱了GNSS信号,使其不适合在森林径中导航。此外,我们突出了在森林走廊中使用点云登记的定位相关的不确定性。我们证明它不是雪降水,而是影响我们系统在环境中定位的能力的积雪。最后,我们从我们的实地运动中揭示了一些经验教训和挑战,以支持在冬季条件下更好的实验工作。
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研究界,工业和社会中地面移动机器人(MRS)和无人机(UAV)的重要性正在迅速发展。如今,这些代理中的许多代理都配备了通信系统,在某些情况下,对于成功完成某些任务至关重要。在这种情况下,我们已经开始见证在机器人技术和通信的交集中开发一个新的跨学科研究领域。该研究领域的意图是将无人机集成到5G和6G通信网络中。这项研究无疑将在不久的将来导致许多重要的应用。然而,该研究领域发展的主要障碍之一是,大多数研究人员通过过度简化机器人技术或通信方面来解决这些问题。这阻碍了达到这个新的跨学科研究领域的全部潜力的能力。在本教程中,我们介绍了一些建模工具,从跨学科的角度来解决涉及机器人技术和通信的问题所需的一些建模工具。作为此类问题的说明性示例,我们将重点放在本教程上,讨论通信感知轨迹计划的问题。
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凭借在运动扫描系统生产的LIDAR点云注册的目的,我们提出了一种新颖的轨迹调整程序,可以利用重叠点云和关节集成之间所选可靠的3D点对应关系的自动提取。 (调整)与所有原始惯性和GNSS观察一起。这是使用紧密耦合的方式执行的动态网络方法来执行,这通过在传感器处的错误而不是轨迹等级来实现最佳补偿的轨迹。 3D对应关系被制定为该网络内的静态条件,并且利用校正的轨迹和可能在调整内确定的其他参数,以更高的精度生成注册点云。我们首先描述了选择对应关系以及将它们作为新观察模型作为动态网络插入的方法。然后,我们描述了对具有低成本MEMS惯性传感器的实用空气激光扫描场景中提出框架的性能进行评估。在进行的实验中,建议建立3D对应关系的方法在确定各种几何形状的点对点匹配方面是有效的,例如树木,建筑物和汽车。我们的结果表明,该方法提高了点云登记精度,否则在确定的平台姿态或位置(以标称和模拟的GNSS中断条件)中的错误受到强烈影响,并且可能仅使用总计的一小部分确定未知的触觉角度建立的3D对应数量。
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Autonomous Micro Aerial Vehicles are deployed for a variety tasks including surveillance and monitoring. Perching and staring allow the vehicle to monitor targets without flying, saving battery power and increasing the overall mission time without the need to frequently replace batteries. This paper addresses the Active Visual Perching (AVP) control problem to autonomously perch on inclined surfaces up to $90^\circ$. Our approach generates dynamically feasible trajectories to navigate and perch on a desired target location, while taking into account actuator and Field of View (FoV) constraints. By replanning in mid-flight, we take advantage of more accurate target localization increasing the perching maneuver's robustness to target localization or control errors. We leverage the Karush-Kuhn-Tucker (KKT) conditions to identify the compatibility between planning objectives and the visual sensing constraint during the planned maneuver. Furthermore, we experimentally identify the corresponding boundary conditions that maximizes the spatio-temporal target visibility during the perching maneuver. The proposed approach works on-board in real-time with significant computational constraints relying exclusively on cameras and an Inertial Measurement Unit (IMU). Experimental results validate the proposed approach and shows the higher success rate as well as increased target interception precision and accuracy with respect to a one-shot planning approach, while still retaining aggressive capabilities with flight envelopes that include large excursions from the hover position on inclined surfaces up to 90$^\circ$, angular speeds up to 750~deg/s, and accelerations up to 10~m/s$^2$.
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