一种基于一致性的四旋翼无人机编队避障方法

针对一致性方法无法实现四旋翼无人机编队避障的问题,在航迹规划空间中引入势场来避免编队无人机间和编队无人机与障碍物间发生碰撞。以一致性方法为基础引导四旋翼无人机形成期望队形,为提高算法的收敛速度并且避免四旋翼无人机之间发生碰撞,增加了目标点的引力场和无人机间的斥力场;为有效避开外部环境中的障碍物,增加了障碍物的斥力场,并且构建了四旋翼无人机编队避障控制协议。仿真结果表明,新构建的控制协议能够引导编队无人机有效避开障碍物,并且能够恢复预期编队队形。     

基于Leader-Follower的多无人机编队轨迹跟踪设计

针对四旋翼无人机（UAV）群在轨迹跟踪过程中易受外界干扰而引起跟踪误差的问题，设计了基于Leader-Follower的多无人机协同编队轨迹跟踪控制方法。在该系统中，首先通过积分反步法（IBS）对所建四旋翼飞行器模型设计Leader无人机的轨迹跟踪控制器。其次设计了滑模控制（SMC）器，以控制Leader与Follower无人机实现期望的编队队形并同时跟踪参考轨迹。然后通过数值仿真验证了算法的有效性，仿真结果表明，系统具有良好的控制精度。最后通过视觉定位系统进行实验，结果表明所设计的控制器能够实现多个无人机轨迹跟踪和编队控制，所设计的算法具有可行性。     

基于相对方向的非线性无人机群反步编队跟踪控制

针对具有未知动态模型的非线性无人机群的编队问题，设计了基于神经网络的反步控制策略。首先，通过径向基(RBF)神经网络来逼近无人机的未知非线性动态，增加系统的鲁棒性和抗扰能力；然后，引入方向刚性图理论，结合反步控制策略，设计了仅基于方向信息的无人机群编队分布式控制器，并通过Lyapunov方法证明了控制系统的稳定性；最后，通过Simulink仿真验证了控制器的有效性。     

基于零空间方法的四旋翼无人机避障与协同编队控制

针对四旋翼无人机在编队飞行执行任务时可能遭遇障碍物问题,考虑多无人机避障及机间避撞的需求,提出 1种基于零空间方法的四旋翼无人机避障与协同编队控制算法。首先,建立四旋翼无人机动力学模型,并建立虚拟控制量简化控制模型;其次,基于零空间方法进行避障与协同编队控制算法研究,将无人机任务执行分解为目标趋向任务、避障避撞任务和协同编队任务,并根据优先级进行任务融合得到期望速度;再次,基于 PID方法设计控制律;最后,通过仿真验证所提控制算法的有效性。所提方法可保证四旋翼无人机在编队飞行中遭遇障碍物时的飞行安全。     

基于距离的无人机编队路径跟踪控制

针对复杂通信环境下无人机编队跟踪控制问题，提出了基于距离的无人机编队路径跟踪容错控制方法。基于刚性图编队控制框架，引入距离误差，实现编队控制，并针对无人机编队生成的收敛速度问题，引入预设性能技术，以指定跟踪性能生成无人机编队。针对无人机执行器可能出现的故障，利用自适应滑模容错控制技术，实现具有容错性能的编队控制。考虑无人机在飞行环境中遇到的不确定扰动和模型自身存在的未建模动态，引入神经网络控制器，提高控制算法的抗干扰能力。最后，基于Lyapunov理论证明了所设计编队控制系统的稳定性，仿真验证了控制方法的有效性。     

基于PX4飞控的多旋翼无人机编队跟踪系统设计

为解决单架无人机续航能力不足、执行任务单薄、应用场合受限等问题，目前多无人机协同跟踪具有极其重要的研究价值。以多旋翼无人机为研究对象，设计了一种基于 PX4飞控的多旋翼无人机协同编队系统。利用飞控底层软件，将设计的制导律进行移植，通过ROS系统对无人机进行外部控制，各个僚机和长机之间能够实时获取其他无人机位置，然后通过控制器得到指令速度，从而形成预设跟踪编队。仿真实验结果表明，整个编队系统对目标的跟踪精确有效，并且所设计的制导律可以在PX4飞控架构下实现对地面目标的编队跟踪，提高了多旋翼编队跟踪系统的稳定性。     

基于小脑模型关节控制器的无人机集群快速终端滑模容错控制

针对受执行器故障和外界干扰影响的集群无人机（UAV）协同编队控制问题，提出了一种自适应快速非奇异积分滑模（FNISM）容错控制（FTC）方法。为使集群无人机在执行任务时具有良好的协同跟踪性能，通过对无人机实际飞行情况的分析，考虑了无人机编队飞行时的执行器故障和尾涡扰动等对跟踪性能的不利影响。采用小脑模型关节控制器神经网络（CMANN）来估计并消除外部干扰的影响，同时运用CMANN逼近补偿执行器故障。研究表明：所提出的容错控制方案可以保证无人机编队闭环系统在故障情况下的最终一致有界稳定，并且可以通过减小滑模设计参数提高收敛速度，通过增大虚拟和实际控制器参数提高控制精度。4架无人机的集群编队在该方法、基于径向基神经网络（RBFNN）的鲁棒动态面容错控制、比例微分（PD）滑模容错控制3种方法下的对比仿真结果表明该方法在无人机集群编队出现故障时具有更优异的协同控制性能。     

基于预测控制的无人机编队内部避碰

针对无人机编队内部避碰问题,首先采用基于预测控制的方法,解决了在即将发生碰撞情况下无人机的航向调整问题;然后,建立了航路回归模型,解决了无人机避碰后,迅速回归预定航路的问题。仿真结果表明,文章给出的避碰方法能够有效解决无人机编队内部碰撞问题。     

基于扩张状态观测器的四旋翼无人机姿态受限控制

针对在参数不确定性和外部干扰影响下的四旋翼无人机姿态受限控制问题,设计了一种基于扩张状态观测器(Extended State Observer,ESO)的四旋翼无人机姿态受限控制方法。首先,基于四旋翼无人机姿态运动模型构造ESO对集中扰动进行在线估计;其次,结合障碍Lyapunov函数设计反步控制器,以克服无人机姿态受限问题;另外,还对所提出的控制策略进行了稳定性分析。最后,通过对比仿真试验验证了该控制方法的有效性和优越性。     

面向无人机空中加油紧密编队的鲁棒控制方法

针对无人机空中加油紧密编队系统鲁棒控制问题，提出了一种基于障碍函数的自适应干扰观测器的分布式鲁棒编队控制方法。对固定翼无人机外环动力学模型进行转换，构造了具有非匹配和匹配扰动的二阶多体系统简化模型，并基于障碍函数设计了相应通道的自适应干扰观测器；利用邻机状态信息定义了相应的一致误差函数，在此基础上，基于编队系统通信拓扑结构，引入干扰补偿机制，开发了空中加油无人机紧密编队系统分布式鲁棒控制器，以实现理想的异构无人机编队跟踪控制性能。基于Lyapunov稳定性理论，分析了闭环系统的稳定性和收敛性。最后，通过将所提方法应用在由不同型号的1架加油机和2架受油机构成的编队系统上，进行数值仿真验证。所得到仿真结果与理论分析一致，验证了设计的干扰观测器和控制器的有效性。     

Adaptive leader–follower formation control for swarms of unmanned aerial vehicles with motion constraints and unknown disturbances

In this paper, the 3D leader–follower formation control problem, which focuses on swarms of fixed-wing Unmanned Aerial Vehicles (UAVs) with motion constraints and disturbances, has been investigated. Original formation errors of the follower UAVs have been transformed into the Frenet-Serret frame. Formation control laws satisfying five motion constraints (i.e., linear velocity, linear acceleration, heading rate, climb rate and climb angle) have been designed. The convergence of the control laws has been discussed via the Lyapunov stability tool. In addition, to address the unknown disturbances, an adaptive disturbance observer is exploited. Furthermore, formation control laws involving estimated disturbances are presented as well. The collision avoidance between UAVs is achieved with the artificial potential method. Simulation results obtained using four scenarios verify the effectiveness of the proposed method in situations with constant disturbances and varying disturbances, as well as without disturbances.     

基于干扰观测器的四旋翼无人机离散时间容错控制

为了飞行控制方案便于在计算机上实现，针对具有外部干扰和执行器加性故障的四旋翼无人机（UAV）角度运动方程，给出一种基于干扰观测器的离散时间跟踪控制方案。通过设计离散时间干扰观测器抑制外部干扰和执行器故障的不利影响，并结合干扰观测器设计离散时间控制器。通过数值仿真验证了基于干扰观测器的离散时间容错控制方案的有效性。仿真结果表明，设计的离散控制器能够保证外部干扰和执行器故障综合作用下的四旋翼UAV系统跟踪控制性能。     

Adaptive formation control of quadrotor unmanned aerial vehicles with bounded control thrust

In this paper, the flight formation control problem of a group of quadrotor unmanned aerial vehicles (UAVs) with parametric uncertainties and external disturbances is studied. Unit-quaternions are used to represent the attitudes of the quadrotor UAVs. Separating the model into a translational subsystem and a rotational subsystem, an intermediary control input is introduced to track a desired velocity and extract desired orientations. Then considering the internal parametric uncertainties and external disturbances of the quadrotor UAVs, the priori-bounded intermediary adaptive control input is designed for velocity tracking and formation keeping, by which the bounded control thrust and the desired orientation can be extracted. Thereafter, an adaptive con-trol torque input is designed for the rotational subsystem to track the desired orientation. With the proposed control scheme, the desired velocity is tracked and a desired formation shape is built up. Global stability of the closed-loop system is proven via Lyapunov-based stability analysis. Numer-ical simulation results are presented to illustrate the effectiveness of the proposed control scheme.     

Observer-based control for the platform of a tethered space robot

This paper addresses the attitude control problem of a space tethered robot platform in the presence of unknown external disturbance caused by a connecting elastic tether. The tether-generated unknown disturbance leads to tremendous challenges for attitude control of the platform. In this work, the perturbed attitude dynamics of the platform are derived with a consideration of the libration of the elastic tether, and then with the purpose of compensating the unknown disturbance, major attention is dedicated to develop a nonlinear disturbance observer based on gyros measurements, after which, an adaptive attitude scheme is proposed by combining the disturbance observer with a sliding mode controller. Finally, benefits from the observer based on an adaptive controller are validated by series of numerical simulations.     

基于扰动观测器的无人机固定时间编队协同控制

针对无人机的编队控制问题,基于虚拟领航者编队方法,提出了 1种基于固定时间超螺旋干扰观测器的反步控制策略。首先,设计了 1种固定时间超螺旋扰动观测器,以保证在固定时间内,对无人机编队机动所受扰动的快速观测;其次,针对编队控制问题,设计了基于超螺旋扰动观测器的反步控制策略,该控制器显著降低了抖振效应;然后,使用李雅普诺夫理论和固定时间理论,分析了控制策略的固定时间稳定性;最后,通过仿真算例验证了所提出的控制策略的有效性与可行性。     

Switching control of morphing aircraft based on Q-learning

This paper investigates a switching control strategy for the altitude motion of a morphing aircraft with variable sweep wings based on Q-learning. The morphing process is regarded as a function of the system states and a related altitude motion model is established. Then, the designed controller is divided into the outer part and inner part, where the outer part is devised by a combination of the back-stepping method and command filter technique so that the ‘explosion of complexity’ problem is eliminated. Moreover, the integrator structure of the altitude motion model is exploited to simplify the back-stepping design, and disturbance observers inspired from the idea of extended state observer are devised to obtain estimations of the system disturbances. The control input switches from the outer part to the inner part when the altitude tracking error converges to a small value and linear approximation of the altitude motion model is applied. The inner part is generated by the Q-learning algorithm which learns the optimal command in the presence of unknown system matrices and disturbances. It is proved rigorously that all signals of the closed-loop system stay bounded by the developed control method and controller switching occurs only once. Finally, comparative simulations are conducted to validate improved control performance of the proposed scheme.     

新型自适应Terminal滑模控制及其应用

针对一类高阶MIMO非线性系统设计了基于快速模糊干扰观测器的自适应Terminal滑模控制方案.通过设计快速模糊干扰观测器,克服了传统模糊干扰观测器在误差较小时收敛速度慢的缺点.严格证明了跟踪误差及观测误差均在有限时间内收敛到零的小区域.最后在高超声速条件下,对空天飞行器再入过程的姿态控制进行仿真,结果表明了所设计干扰观测器的优越性和闭环控制方案的有效性.      

Fixed-time adaptive model reference sliding mode control for an air-to-ground missile

This paper addresses the fixed-time adaptive model reference sliding mode control for an air-to-ground missile associated with large speed ranges, mismatched disturbances and un-modeled dynamics. Firstly, a sliding mode surface is developed by the tracking error of the state equation and the model reference state equation with respect to the air-to-ground missile. More specifically,a novel fixed-time adaptive reaching law is presented. Subsequently, the mismatched disturbances and the un-modeled dynamics are treated as the model errors of the state equation. These model errors are estimated by means of a fixed-time disturbance observer, and they are also utilized to compensate the proposed controller. Therefore, the fixed-time controller is obtained by an adaptive reaching law and a fixed-time disturbance observer. Closed-loop stability of the proposed controller is established. Finally, simulation results including Monte Carlo simulations, nonlinear six-DegreeOf-Freedom(6-DOF) simulations and different ranges are presented to demonstrate the efficacy of the proposed control scheme.     

可重复使用飞行器的保性能姿态跟踪控制方法

针对可重复使用飞行器再入姿态跟踪控制问题,在考虑执行器饱和、气动参数摄动和外部扰动的情况下,提出了一种保性能姿态跟踪控制方案。通过构造预设性能函数,使姿态跟踪误差在预先设置的包络内演化,保证了系统的瞬态和稳态性能;其次,借助于高增益扩张状态观测器解决了气动参数摄动和外部扰动的问题;之后,基于反步控制框架,设计了一种低复杂度的输出反馈扰动补偿控制方法,保证跟踪误差的收敛性。与已有方法相比,所设计的方法不包含一些复杂的非线性动力学近似技术,如神经网络等,降低了参数调节的复杂性,且无需对虚拟控制律重复微分,避免了"微分爆炸"问题。同时,Lyapunov稳定性分析表明,该方法能够保证误差变量的预期收敛以及其他闭环系统信号的有界性。最后,通过对比仿真验证了所提方法的有效性及可行性。     

基于有向图的航天器编队飞行自适应姿态协同控制

在有向通信拓扑下研究了编队航天器自适应姿态协同控制问题。针对航天器编队飞行系统中存在外部扰动和模型不确定性的情况,通过选取包含相对姿态误差和绝对姿态误差的辅助变量,提出了一种鲁棒自适应控制策略。提出了自适应律估计转动惯量矩阵和扰动上界等未知参数,并且利用Lyapunov稳定性理论分析了闭环系统的渐近稳定性。与滑模控制等传统鲁棒控制不同,所设计的鲁棒自适应控制器是连续的,更便于航天器编队飞行系统的实现。最后通过仿真验证了该控制策略能够实现高精度的编队飞行跟踪控制。