旋翼无人机环境覆盖与探索规划方法综述

随着微型空中机器人技术的迅速发展,利用小型旋翼无人机对目标环境进行自主覆盖与探索成为当前机器人领域的研究热点.鉴于此,首先对机器人环境覆盖规划与探索规划的研究内容进行简要介绍;然后按照覆盖规划、探索规划以及同时覆盖与探索规划3个方面展开综述,详细分析不同方法的基本工作原理、优势以及局限性;最后根据研究现状总结目前研究中...     

临近空间太阳能飞行器能源系统控制综述

临近空间太阳能飞行器是由太阳能驱动、可在临近空间连续飞行的长航时无人飞行器,近年来其相关研究已成为各国关注的焦点.能源系统是支撑太阳能飞行器长时驻空的关键,实现连续跨昼夜的不间断能量供给是能源系统领域研究的首要目标.围绕临近空间太阳能飞行器集群化能源系统发展过程中的主要问题和研究现状,首先梳理飞行器应用场景下能源系统的控制目标与多重约束,进而系统论述集群化能源系统结构、功能及建模方法;然后,总结集群化能源系统功率分配、储能均衡以及通信受限下能流控制的发展现状,阐述基于强化学习的能量在线调度策略的最新成果,分析现有策略的有效性及不足之处;最后,结合太阳能飞行器的实际需求,探讨能源系统的未来发展趋势与研究方向.     

A survey of guidance,navigation, and control systems for autonomous multi-rotor small unmanned aerial systems

This survey paper presents a holistic perspective on the state-of-the-art in the design of guidance, navigation, and control systems for autonomous multi-rotor small unmanned aerial systems (sUAS). By citing more than 300 publications, this work recalls fundamental results that enabled the design of these systems, describes some of the latest advances, and compares the performance of several techniques. This paper also lists some techniques that, although already employed by different classes of mobile robots, have not been employed yet on sUAS, but may lead to satisfactory results. Furthermore, this publication highlights some limitations in the theoretical and technological solutions underlying existing guidance, navigation, and control systems for sUAS and places special emphasis on some of the most relevant gaps that hinder the integration of these three systems. In light of the surveyed results, this paper provides recommendations for macro-research areas that would improve the overall quality of autopilots for autonomous sUAS and would facilitate the transition of existing results from sUAS to larger autonomous aircraft for payload delivery and commercial transportation.     

Autopilots for small unmanned aerial vehicles: A survey

This paper presents a survey of the autopilot systems for small or micro unmanned aerial vehicles (UAVs). The objective is to provide a summary of the current commercial, open source and research autopilot systems for convenience of potential small UAV users. The UAV flight control basics are introduced first. The radio control system and autopilot control system are then explained from both the hardware and software viewpoints. Several typical off-the-shelf autopilot packages are compared in terms of sensor packages, observation approaches and controller strengths. Afterwards some open source autopilot systems are introduced. Conclusion is made with a summary of the current autopilot market and a remark on the future development.     

基于同步的多旋翼无人机非线性模型自适应参数辨识

针对多旋翼无人机的非线性模型,提出了一种基于同步理论的自适应参数辨识方法.其主要思想是通过设计一种"从系统",在实现状态与原有非线性系统同步的同时,设计自适应更新律,使得对参数的估计收敛到真值.所提方法能够适用于以非线性形式存在的参数,其渐近稳定性由李雅普诺夫方法和拉塞尔不变性原理予以证明.仿真实例可以验证,合理选择自适应增益,即便真值发生突变,所提方法也能保证估计值快速收敛到最新的真值.     

基于NuttX的多旋翼飞行器控制系统设计

针对执行复杂任务的多旋翼飞行器对多任务和安全性的需求,设计一种基于N utt X实时操作系统的飞行控制系统,并增加失效保护协处理器,达到减少开发过程中坠机几率和提高主处理器任务容量的目的。实验表明,此平台在满足稳定控制飞行的同时,能明显减小开发难度,缩短开发周期,并且给后续算法开发保留了充足的运行资源。     

Unmanned aerial vehicles UAVs attitude,height, motion estimation and control using visual systems

This paper presents an implementation of an aircraft pose and motion estimator using visual systems as the principal sensor for controlling an Unmanned Aerial Vehicle (UAV) or as a redundant system for an Inertial Measure Unit (IMU) and gyros sensors. First, we explore the applications of the unified theory for central catadioptric cameras for attitude and heading estimation, explaining how the skyline is projected on the catadioptric image and how it is segmented and used to calculate the UAV’s attitude. Then we use appearance images to obtain a visual compass, and we calculate the relative rotation and heading of the aerial vehicle. Additionally, we show the use of a stereo system to calculate the aircraft height and to measure the UAV’s motion. Finally, we present a visual tracking system based on Fuzzy controllers working in both a UAV and a camera pan and tilt platform. Every part is tested using the UAV COLIBRI platform to validate the different approaches, which include comparison of the estimated data with the inertial values measured onboard the helicopter platform and the validation of the tracking schemes on real flights.     

基于四元数衍生无迹卡尔曼滤波的二段式多旋翼无人机姿态估计算法

对传统多旋翼无人机姿态估计算法难以兼顾高精度、强实时性以及抗干扰能力差的问题,首先基于一种计算量较小的衍生无迹卡尔曼滤波算法,在量测更新中,将加速度数据和磁力计数据分为两个阶段进行姿态四元数校正处理,然后从旋转四元数的本质出发,推测出四元数各元素分别包含着不同的姿态角信息,最后将校正四元数分别乘上为降低校正过程中的相互干扰所设计的系数,提出一种基于四元数衍生无迹卡尔曼滤波的二段式多旋翼无人机姿态估计算法.通过使用PIXHAWK飞控数据,与传统姿态估计算法进行仿真实验对比,实验表明,本文提出算法与传统使用扩展卡尔曼滤波(EKF)或无迹卡尔曼滤波(UKF)的姿态估计算法相比,在实时性、解算精度和抗干扰能力方面有较大提升.     

Robust attitude control for tail‐sitter unmanned aerial vehicles in flight mode transitions

Tail‐sitter unmanned aerial vehicles (UAVs) can flight as rotorcrafts as well as fixed‐wing aircrafts, but it is hard to control the flight mode transition. The vehicle dynamics involves serious parametric uncertainties, highly nonlinear dynamics, and is easy to be affected by external disturbances, especially during the mode transition. This paper presents a robust control method for a kind of tail‐sitter UAVs to achieve the flight mode transition. The robust controller is proposed based on the state‐feedback control scheme and the robust compensation method. The proposed control method does not need to switch the coordinate system, the controller structure, or the controller parameters during the mode transitions. Theoretical analysis is given to guarantee the robustness stability of the designed flight control system. Numerical simulation results are presented to show the advantages of the proposed control method compared with the state‐feedback control method and the sliding mode control approach.     

航天器姿轨控制研究综述:微分几何控制方法

作为空间任务顺利执行的关键技术,航天器姿态和轨道控制具有典型的非线性特征,其本质是对在矩阵李群SO (3)和SE (3)上演化的动态系统进行控制.与传统的参数化模型相比,航天器的矩阵李群模型对姿轨表征具有全局性、非奇异性和唯一性等固有优势,为控制设计提供了数学简洁、精度高、适用性好的模型基础.因此,近年来基于微分几何控制方法直接对其进行系统分析和控制设计的研究逐渐兴起,取得了一系列突破性成果.鉴于此,首先,系统地论述微分几何控制理论在航天器姿轨控制应用中的研究现状和进展;然后,面向空间任务的实际需要,分别对基于矩阵李群模型的单体航天器姿态控制、姿轨耦合控制、网络化航天器集群姿轨协同控制3个技术方向加以讨论;最后,对上述研究领域中存在的难题和挑战进行总结,并对未来发展方向进行展望.     

Safe formation control ofmultiple unmanned aerial vehicles: control design and safety-stability analysis

Both safety and stability are primary performance criteria for multi-unmanned aerial vehicle (multi-UAV) systems in many coordination tasks. Existing approaches often consider safety and stability separately. It is necessary and urgent to develop a safety-stability control strategy to merge these two performance criteria. In this paper, a unified approach is developed to consider safety and stability for multi-UAV formation control. The stability criterion is represented by a Lyapunov function and safety criterion is represented by a barrier function and then a relaxed converse control Lyapunov-barrier theorem is obtained. With the help of a relaxed converse control Lyapunov-barrier function (RCCLBF), a distributed safety-stability formation control strategy is proposed for the multi-UAV system. By transforming the solution of RCCLBF to a Lyapunovlike stabilization problem, we show that the proposed formation control strategy can drive the UAVs staying within a specified safe set. Simulation results are provided to validate the proposed safety-stability formation control strategy.     

新型多旋翼作业型空中机器人自抗扰控制

针对输电线路树障清理作业任务对空中机器人平台稳定性、平动性和抗扰性的高要求,为克服传统平面配置多旋翼无人机姿态配合式位置移动的缺点,本文在全驱动多旋翼飞行器设计思想的启发下,提出并设计了一种无需姿态配合即可实现前后平移运动的非平面作业型多旋翼空中机器人.首先分别建立其姿态的运动学和动力学模型,然后采用自抗扰控制技术设计了该机器人的位置和姿态跟踪控制律.多组仿真和样机实验结果表明,本文所设计的非平面配置旋翼空中机器人在作业过程中的接触力扰动下具有良好稳定性、平动性和抗扰性.     

A neuro-evolutionary approach to control surface segmentation for micro aerial vehicles

This paper addresses control surface segmentation in micro aerial vehicles (MAVs) by leveraging neuro-evolutionary techniques that allow the control of a higher number of control surfaces. Applying classical control methods to MAVs is a difficult process due to the complexity of the control laws with fast and highly non-linear dynamics. These methods are mostly based on models that are difficult to obtain for dynamic and stochastic environments. Moreover, these problems are exacerbated when both the number of control surfaces increases and the model’s accuracy in determining the impact of each control surface decreases. Instead, we focus on neuro-evolutionary techniques that have been successfully applied in many domains with limited models and highly non-linear dynamics. Wind tunnel simulations with Athena Vortex Lattice show that MAV performances are improved in terms of both reduced deflection angles and reduced drag (up to 5%) over a simplified model in two sets of experiments with different objective functions. We also show robustness to actuator failure with desired roll moment values still attained with failed actuators in the system through the neuro-controller.     

Mission control of multiple unmanned aerial vehicles: a workload analysis

With unmanned aerial vehicles (UAVs), 36 licensed pilots flew both single-UAV and dual-UAV simulated military missions. Pilots were required to navigate each UAV through a series of mission legs in one of the following three conditions: a baseline condition, an auditory autoalert condition, and an autopilot condition. Pilots were responsible for (a) mission completion, (b) target search, and (c) systems monitoring. Results revealed that both the autoalert and the autopilot automation improved overall performance by reducing task interference and alleviating workload. The autoalert system benefited performance both in the automated task and mission completion task, whereas the autopilot system benefited performance in the automated task, the mission completion task, and the target search task. Practical implications for the study include the suggestion that reliable automation can help alleviate task interference and reduce workload, thereby allowing pilots to better handle concurrent tasks during single- and multiple-UAV flight control.     

Motion control problems for multimode unmanned aerial vehicles

This paper considers flight control specifics for modern unmanned aerial vehicles with paths described by a wide range of altitudes, including super-aerodynamic flights. It is noted that this type of aerial vehicles belongs to multimode dynamic objects with varying characteristics in the course of their operation. Adaptive control methods used in control systems for unmanned aerial vehicles are overviewed. Finally, adaptive control capabilities are studied for the vehicle’s angular position in gliding and cruising modes under combined jet reaction and aerodynamic control.     

涵道风扇飞行器飞行控制技术与分类

飞行控制设计的最新进展提高了复杂自主飞行器完成各类任务的能力.在各类垂直起降飞行器中,涵道风扇飞行器(DFAVs)是一种非常重要的尾座式飞行器,其运动和驱动部件由称为涵道的环形机身所屏蔽.这一结构使得其能够很好地保护飞行器自身和操作人员的安全,让飞行器能够在狭窄、杂乱和危险的环境中飞行.此外,DFAVs具有固定翼飞机和直升机的特点,能够同时展现它们的优良特性,如长时居高监视能力和大有效载荷能力.本文是关于DFAVs的第1篇综述论文,旨在概述与其相关的几个方面的最新进展.首先,综述了世界范围内开发的此类飞行平台的历史与分类,并总结了它们的优缺点.然后,介绍了用于控制这些飞行器的多种控制方法.最后,给出总结,并讨论了现存的挑战,以及新的研究趋势.     

Flocking control of a fleet of unmanned aerial vehicles

Current applications using single unmanned vehicle have been gradually extended to multiple ones due to their increased efficiency in mission accomplishment, expanded coverage areas and ranges, as well as enhanced system reliability. This paper presents a flocking control method with application to a fleet of unmanned quadrotor helicopters (UQHs). Three critical characteristics of formation keeping, collision avoidance, and velocity matching have been taken into account in the algorithm development to make it capable of accomplishing the desired objectives (like forest/pipeline surveillance) by safely and efficiently operating a group of UQHs. To achieve these, three layered system design philosophy is considered in this study. The first layer is the flocking controller which is designed based on the kinematics of UQH. The modified Cucker and Smale model is used for guaranteeing the convergence of UQHs to flocking, while a repelling force between each two UQHs is also added for ensuring a specified safety distance. The second layer is the motion controller which is devised based on the kinetics of UQH by employing the augmented state-feedback control approach to greatly minimize the steady-state error. The last layer is the UQH system along with its actuators. Two primary contributions have been made in this work: first, different from most of the existing works conducted on agents with double integrator dynamics, a new flocking control algorithm has been designed and implemented on a group of UQHs with nonlinear dynamics. Furthermore, the constraint of fixed neighbouring distance in formation has been relaxed expecting to significantly reduce the complexity caused by the increase of agents number and provide more flexibility to the formation control. Extensive numerical simulations on a group of UQH nonlinear models have been carried out to verify the effectiveness of the proposed method.     

无人驾驶飞行器姿态的非线性扰动抑制控制

本文研究了无人驾驶飞行器(unmanned aerial vehicle,UAV)的姿态跟踪控制问题.针对在飞行器姿态跟踪时存在的系统模型不确定性和外界扰动,提出了一种基于四元数的姿态跟踪控制方法,基于UAV的姿态误差模型分别设计系统的观测器和控制器.首先,以四元数为姿态参数建立系统的非线性误差模型;在此基础之上,设计一种非线性干扰观测器(nonlinear disturbance observer,NDOB)用以在线估计误差模型中的复合扰动,并在控制输入端进行相应的补偿.然后通过设计非线性广义预测控制律设镇定误差系统,实现姿态跟踪.最后基于频域理论分析了非线性干扰观测器的扰动抑制性能.仿真与实验结果表明本文提出的方法在系统存在复合扰动的情况下能使系统姿态有效的跟踪期望值.     

应用于多旋翼MAVs的姿态测量系统

应用一个三轴加速度计、三个单轴角速率陀螺和一个三轴磁强计等微机械惯性传感器,设计廉价轻量姿态测量系统,研究了姿态角推算算法。在以往的姿态测量系统中,陀螺偏差和动加速度的影响限制其应用。将角速度陀螺的误差作为状态量导入到系统,动加速度作为噪音项导入到观测方程中,然后利用扩展卡尔曼滤波器来构成姿态估计算法来降低误差。实际飞行中对比商用高精度传感器和多次室外飞行测试表明,设计的系统能够应于旋翼MAVs。