This paper addresses the problem of position estimation in UAVs operating in a cluttered environment where GPS information is unavailable. A model learning-based approach is proposed that takes in the rotor RPMs and past state as input and predicts the one-step-ahead position of the UAV using a novel spectral-normalized memory neural network (SN-MNN). The spectral normalization guarantees stable and reliable prediction performance. The predicted position is transformed to global coordinate frame which is then fused along with the odometry of other peripheral sensors like IMU, barometer, compass etc., using the onboard extended Kalman filter to estimate the states of the UAV. The experimental flight data collected from a motion capture facility using a micro-UAV is used to train the SN-MNN. The PX4-ECL library is used to replay the flight data using the proposed algorithm, and the estimated position is compared with actual ground truth data. The proposed algorithm doesn't require any additional onboard sensors, and is computationally light. The performance of the proposed approach is compared with the current state-of-art GPS-denied algorithms, and it can be seen that the proposed algorithm has the least RMSE for position estimates.
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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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本文在移动平台上介绍了四摩托车的自动起飞和着陆系统。设计的系统解决了三个具有挑战性的问题:快速姿势估计,受限的外部定位和有效避免障碍物。具体而言,首先,我们基于Aruco标记设计了着陆识别和定位系统,以帮助四极管快速计算相对姿势。其次,我们利用基于梯度的本地运动计划者快速生成无冲突的参考轨迹;第三,我们构建了一台自主状态机器,使四极管能够完全自治完成其起飞,跟踪和着陆任务;最后,我们在模拟,现实世界和室外环境中进行实验,以验证系统的有效性并证明其潜力。
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We propose a multisensor fusion framework for onboard real-time navigation of a quadrotor in an indoor environment, by integrating sensor readings from an Inertial Measurement Unit (IMU), a camera-based object detection algorithm, and an Ultra-WideBand (UWB) localization system. The sensor readings from the camera-based object detection algorithm and the UWB localization system arrive intermittently, since the measurements are not readily available. We design a Kalman filter that manages intermittent observations in order to handle and fuse the readings and estimate the pose of the quadrotor for tracking a predefined trajectory. The system is implemented via a Hardware-in-the-loop (HIL) simulation technique, in which the dynamic model of the quadrotor is simulated in an open-source 3D robotics simulator tool, and the whole navigation system is implemented on Artificial Intelligence (AI) enabled edge GPU. The simulation results show that our proposed framework offers low positioning and trajectory errors, while handling intermittent sensor measurements.
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Many aerial robotic applications require the ability to land on moving platforms, such as delivery trucks and marine research boats. We present a method to autonomously land an Unmanned Aerial Vehicle on a moving vehicle. A visual servoing controller approaches the ground vehicle using velocity commands calculated directly in image space. The control laws generate velocity commands in all three dimensions, eliminating the need for a separate height controller. The method has shown the ability to approach and land on the moving deck in simulation, indoor and outdoor environments, and compared to the other available methods, it has provided the fastest landing approach. Unlike many existing methods for landing on fast-moving platforms, this method does not rely on additional external setups, such as RTK, motion capture system, ground station, offboard processing, or communication with the vehicle, and it requires only the minimal set of hardware and localization sensors. The videos and source codes are also provided.
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在本文中,我们分析了具有基于视觉导航的无人机(UAV)的时间延迟动力学对控制器设计的影响。时间延迟是网络物理系统中不可避免的现象,并且对无人机的控制器设计和轨迹产生具有重要意义。时间延迟对无人机动态的影响随着基于视力较慢的导航堆栈的使用而增加。我们表明,文献中的现有模型不包括时间延迟,不适合控制器调整,因为一个微不足道的解决方案始终存在错误的解决方案。我们确定的微不足道的解决方案表明,使用无限控制器的利益来实现最佳性能,这与实际发现相矛盾。我们通过引入无人机的新型非线性时间延迟模型来避免这种缺点,然后获得与每个UAV控制回路相对应的一组线性解耦模型。分析了角度和高度动力学的线性时间延迟模型的成本函数,与无延迟模型相反,我们显示了有限的最佳控制器参数的存在。由于使用了时间延迟模型,我们在实验上表明,所提出的模型准确地表示系统稳定性限制。由于时间延迟的考虑,我们使用基于视觉探视的无人机(VO)导航,在跟踪峰值速度为2.09 m/s的lemsistate轨迹时,我们实现了RMSE 5.01 cm的跟踪结果,这与最新-艺术。
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在过去的几年中,无人驾驶汽车(UAV)的领域已经达到了高水平的成熟度。因此,将此类平台从封闭的实验室带到与人类的日常互动对于无人机的商业化很重要。本文的一种特殊人类企业感兴趣的方案是有效载荷切换计划,无人机应要求人将有效载荷移交给人类的有效载荷。在此范围内,本文提出了一种新型的实时人类UAV相互作用检测方法,其中开发了基于短期记忆(LSTM)的神经网络,以检测由人类相互作用动态导致的状态概况。提出了一种新的数据预处理技术;该技术利用培训和测试无人机的估计过程参数来构建动态不变测试数据。提出的检测算法是轻量级的,因此可以使用Off Shelf UAV平台实时部署;此外,它仅取决于任何经典无人机平台上存在的惯性和位置测量。提出的方法是在多电动无人机和人类之间的有效载荷切换任务上证明的。使用实时实验收集培训和测试数据。检测方法的准确性为96 \%,即使存在外部风干扰,也没有误报,并且在两种不同的无人机上进行部署和测试时。
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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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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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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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近年来,空中机器人背景下的高速导航和环境互动已成为几个学术和工业研究研究的兴趣领域。特别是,由于其若干环境中的潜在可用性,因此搜索和拦截(SAI)应用程序造成引人注目的研究区域。尽管如此,SAI任务涉及有关感官权重,板载计算资源,致动设计和感知和控制算法的具有挑战性的发展。在这项工作中,已经提出了一种用于高速对象抓握的全自动空中机器人。作为一个额外的子任务,我们的系统能够自主地刺穿位于靠近表面的杆中的气球。我们的第一款贡献是在致动和感觉水平的致动和感觉水平的空中机器人的设计,包括具有额外传感器的新型夹具设计,使机器人能够高速抓住物体。第二种贡献是一种完整的软件框架,包括感知,状态估计,运动计划,运动控制和任务控制,以便快速且强大地执行自主掌握任务。我们的方法已在一个具有挑战性的国际竞争中验证,并显示出突出的结果,能够在室外环境中以6米/分来自动搜索,遵循和掌握移动物体
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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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交付机器人旨在获得高精度以促进完全自主权。需要一个精确的人行行周围环境的三维点云图来估计自定位。有或没有循环结束方法,由于传感器漂移,较大的城市或城市地图映射后累积误差会逐渐增加。因此,使用漂移或错位的地图存在很高的风险。本文提出了一种融合GPS更新3D点云并消除累积错误的技术。提出的方法与其他现有方法显示了定量比较和定性评估的出色结果。
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在本文中,提出了一个稳定稳定的轨迹跟踪控制器,用于多uav有效载荷运输。多uav有效负载系统在无人机和有效负载框架的垂直刚性链接之间具有2DOF磁球接头,因此无人机可以自由滚动或自由投球。这些垂直链接紧密地连接到有效载荷上,无法移动。为完整的有效载体 - uav系统得出了输入输出反馈线性化模型以及有效载荷轨迹跟踪的推力矢量控制。关于跟踪控制定律的理论分析表明,控制定律是指数稳定的,从而确保了沿期望轨迹的安全运输。为了验证拟议的控制定律的性能,提供了数值模拟以及高保真凉亭实时仿真的结果。接下来,针对两种实际情况分析了提议的控制器的鲁棒性:有效载荷和有效载荷质量不确定性的外部干扰。结果清楚地表明,所提出的控制器在实现指数稳定的轨迹跟踪的同时具有稳健性和计算效率。
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本文介绍了设计,开发,并通过IISC-TCS团队为穆罕默德·本·扎耶德国际机器人挑战赛2020年挑战1的目标的挑战1硬件 - 软件系统的测试是抓住从移动和机动悬挂球UAV和POP气球锚定到地面,使用合适的操纵器。解决这一挑战的重要任务包括具有高效抓取和突破机制的硬件系统的设计和开发,考虑到体积和有效载荷的限制,使用适用于室外环境的可视信息的准确目标拦截算法和开发动态多功能机空中系统的软件架构,执行复杂的动态任务。在本文中,设计了具有末端执行器的单个自由度机械手设计用于抓取和突发,并且开发了鲁棒算法以拦截在不确定的环境中的目标。基于追求参与和人工潜在功能的概念提出了基于视觉的指导和跟踪法。本工作中提供的软件架构提出了一种操作管理系统(OMS)架构,其在多个无人机之间协同分配静态和动态任务,以执行任何给定的任务。这项工作的一个重要方面是所有开发的系统都设计用于完全自主模式。在这项工作中还包括对凉亭环境和现场实验结果中完全挑战的模拟的详细描述。所提出的硬件软件系统对反UAV系统特别有用,也可以修改以满足其他几种应用。
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随着未经驾驶汽车(UAV)未经授权操作的数量正在上升,多功能反无人机系统的实施变得必要。在这项工作中,我们开发了一种基于无人机的反无人机系统,该系统采用算法来检测和跟踪无人机无人机,并与无线截距功能结合使用,共同堵塞了流氓无人机,同时为追捕者无人机实现自我定位。在拟议的系统中,软件定义的Radio(SDR)用于在障碍物传输和频谱清除功能之间进行切换,以分别实现所需的GPS破坏和自定位。广泛的现场实验证明了在各种参数设置下在现实世界环境中提出的解决方案的有效性。
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近年来,基于数据驱动的导航和定位方法吸收了注意力,并且在准确性和效率方面优于其所有竞争对手方法。本文介绍了一种称为IMUNET的新体系结构,该架构是对边缘设备实现的位置估算的准确和有效效率,该估算接收了一系列RAW IMU测量。该体系结构已与最新的CNN网络的一维版本进行了比较,该网络最近介绍了用于Edge设备实现的精确性和效率。此外,已经提出了一种使用IMU传感器和Google Arcore API收集数据集的新方法,并已记录了公开可用的数据集。使用四个不同的数据集以及提出的数据集和实际设备实现的全面评估已经证明了体系结构的性能。 Pytorch和Tensorflow框架以及Android应用程序代码中的所有代码都已共享,以改善进一​​步的研究。
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Precise geolocalization is crucial for unmanned aerial vehicles (UAVs). However, most current deployed UAVs rely on the global navigation satellite systems (GNSS) or high precision inertial navigation systems (INS) for geolocalization. In this paper, we propose to use a lightweight visual-inertial system with a 2D georeference map to obtain accurate and consecutive geodetic positions for UAVs. The proposed system firstly integrates a micro inertial measurement unit (MIMU) and a monocular camera as odometry to consecutively estimate the navigation states and reconstruct the 3D position of the observed visual features in the local world frame. To obtain the geolocation, the visual features tracked by the odometry are further registered to the 2D georeferenced map. While most conventional methods perform image-level aerial image registration, we propose to align the reconstructed points to the map points in the geodetic frame; this helps to filter out the large portion of outliers and decouples the negative effects from the horizontal angles. The registered points are then used to relocalize the vehicle in the geodetic frame. Finally, a pose graph is deployed to fuse the geolocation from the aerial image registration and the local navigation result from the visual-inertial odometry (VIO) to achieve consecutive and drift-free geolocalization performance. We have validated the proposed method by installing the sensors to a UAV body rigidly and have conducted two flights in different environments with unknown initials. The results show that the proposed method can achieve less than 4m position error in flight at 100m high and less than 9m position error in flight about 300m high.
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微型航空车(MAV)具有很高的信息收集任务的潜力,以支持搜索和救援方案中的情况意识。在这种情况下,手动控制MAV需要经验丰富的飞行员,并且容易出错,尤其是在真正紧急情况的压力下。灾难情景的条件对于自动MAV系统也充满挑战。通常不知道环境,GNSS可能并不总是可用。我们介绍了一个不依赖全球定位系统的未知环境中自动MAV航班的系统。该方法在多个搜索和救援方案中进行评估,即使在室内和室外区域之间过渡时,也可以进行安全的自动飞行。
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Localization of autonomous unmanned aerial vehicles (UAVs) relies heavily on Global Navigation Satellite Systems (GNSS), which are susceptible to interference. Especially in security applications, robust localization algorithms independent of GNSS are needed to provide dependable operations of autonomous UAVs also in interfered conditions. Typical non-GNSS visual localization approaches rely on known starting pose, work only on a small-sized map, or require known flight paths before a mission starts. We consider the problem of localization with no information on initial pose or planned flight path. We propose a solution for global visual localization on a map at scale up to 100 km2, based on matching orthoprojected UAV images to satellite imagery using learned season-invariant descriptors. We show that the method is able to determine heading, latitude and longitude of the UAV at 12.6-18.7 m lateral translation error in as few as 23.2-44.4 updates from an uninformed initialization, also in situations of significant seasonal appearance difference (winter-summer) between the UAV image and the map. We evaluate the characteristics of multiple neural network architectures for generating the descriptors, and likelihood estimation methods that are able to provide fast convergence and low localization error. We also evaluate the operation of the algorithm using real UAV data and evaluate running time on a real-time embedded platform. We believe this is the first work that is able to recover the pose of an UAV at this scale and rate of convergence, while allowing significant seasonal difference between camera observations and map.
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