Distributed tracking control of unmanned aerial vehicles under wind disturbance and model uncertainty

A distributed robust method is developed for cooperative tracking control of unmanned aerial vehicles under unknown wind disturbance and model uncertainty. The communication network among vehicles is a directed graph with switching topology. Each vehicle can only share its states with its neighbors. Dynamics of the vehicles are nonlinear and affected by the wind disturbance and model uncertainty. Feedback linearization is adopted to transform the dynamics of vehicles into linear systems. To account for the wind disturbance and model uncertainty, a robust controller is designed for each vehicle such that all vehicles ultimately synchronize to the virtual leader in the three-dimensional path. It is theoretically shown that the position states of the vehicles will converge to that of the virtual leader if the communication network has a directed spanning tree rooted at the virtual leader. Furthermore, the robust controller is extended to address the formation control problem. Simulation examples are also given to illustrate the effectiveness of the proposed method. ? 2016 Beijing Institute of Aerospace Information.

Cooperative Navigation for Autonomous Underwater Vehicles Based on Estimation of Motion Radius Vectors

A cooperative navigation algorithm for a group of autonomous underwater vehicles is proposed on the basis of motion radius vector estimation.Combined the dead reckoning data with the mutual range data through an acoustic communication network among the group members, the relative positioning problem can be solved. A novel approach for solving the relative positioning is presented by using a recursive trigonometry technique and extended Kalman filter(EKF). Simulation results verify the correctness and effectiveness of this navigation method.

Adaptive Sliding Mode Control for Re-entry Attitude of Near Space Hypersonic Vehicle Based on Backstepping Design

Combining sliding mode control method with radial basis function neural network(RBFNN), this paper proposes a robust adaptive control scheme based on backstepping design for re-entry attitude tracking control of near space hypersonic vehicle(NSHV) in the presence of parameter variations and external disturbances. In the attitude angle loop, a robust adaptive virtual control law is designed by using the adaptive method to estimate the unknown upper bound of the compound uncertainties. In the angular velocity loop, an adaptive sliding mode control law is designed to suppress the effect of parameter variations and external disturbances. The main benefit of the sliding mode control is robustness to parameter variations and external disturbances. To further improve the control performance, RBFNNs are introduced to approximate the compound uncertainties in the attitude angle loop and angular velocity loop, respectively. Based on Lyapunov stability theory, the tracking errors are shown to be asymptotically stable. Simulation results show that the proposed control system attains a satisfied control performance and is robust against parameter variations and external disturbances.

Design of Neural Network Variable Structure Reentry Control System for Reusable Launch Vehicle

A flight control system is designed for a reusable launch vehicle with aerodynamic control surfaces and reaction control system based on a variable-structure control and neural network theory.The control problems of coupling among the channels and the uncertainty of model parameters are solved by using the method.High precise and robust tracking of required attitude angles can be achieved in complicated air space.A mathematical model of reusable launch vehicle is presented first,and then a controller of flight system is presented.Base on the mathematical model,the controller is divided into two parts:variable-structure controller and neural network module which is used to modify the parameters of controller.This control system decouples the lateraldirectional tunnels well with a neural network sliding mode controller and provides a robust and de-coupled tracking for mission angle profiles.After this a control allocation algorithm is employed to allocate the torque moments to aerodynamic control surfaces and thrusters.The final simulation shows that the control system has a good accurate,robust and de-coupled tracking performance.The stable state error is less than 1°,and the overshoot is less than 5%.

Energy-efficient joint UAV secure communication and 3D trajectory optimization assisted by reconfigurable intelligent surfaces in the presence of eavesdroppers

We consider a scenario where an unmanned aerial vehicle(UAV),a typical unmanned aerial system(UAS),transmits confidential data to a moving ground target in the presence of multiple eavesdroppers.Multiple friendly reconfigurable intelligent surfaces(RISs) help to secure the UAV-target communication and improve the energy efficiency of the UAV.We formulate an optimization problem to minimize the energy consumption of the UAV,subject to the mobility constraint of the UAV and that the achievable secrecy rate at the target is over a given threshold.We present an online planning method following the framework of model predictive control(MPC) to jointly optimize the motion of the UAV and the configurations of the RISs.The effectiveness of the proposed method is validated via computer simulations.

A Comprehensive UAV Indoor Navigation System Based on Vision Optical Flow and Laser FastSLAM

这份报纸论述为室内的 quadrotor 的全面控制，航行，本地化和印射的答案无人的天线车辆(UAV ) 系统。三个主要传感器在 quadrotor 站台上被使用，也就是，一个惯性的测量单位，一个向下看起来的照相机和扫描激光变化查找者。与这安装， UAV 能要用体力地估计它的自己的速度和位置，当没有碰撞，沿着一个房间的内部墙飞时。在一个以后完成飞行，与收集了数据历史性的 UAV 路径和室内的环境能很好被估计。系统的自治航行部分不要求任何遥远的感觉信息或离线的计算力量，当印射被做时离线。完全的飞行测试被执行了验证忠实和性能航行答案。

Survey on path and view planning for UAVs

Background In recent decades,unmanned aerial vehicles(UAVs)have developed rapidly and been widely applied in many domains,including photography,reconstruction,monitoring,and search and rescue.In such applications,one key issue is path and view planning,which tells UAVs exactly where to fly and how to search.Methods With specific consideration for three popular UAV applications(scene reconstruction,environment exploration,and aerial cinematography),we present a survey that should assist researchers in positioning and evaluating their works in the context of existing solutions.Results/Conclusions It should also help newcomers and practitioners in related fields quickly gain an overview of the vast literature.In addition to the current research status,we analyze and elaborate on advantages,disadvantages,and potential explorative trends for each application domain.

水下无人航行器高速航行下的运动特性及仿真控制研究

水下无人航行器具有水下活动范围大、机动性好优点,主要用于大范围地形地貌勘探,水下高速长航程航行时,水下航行器运动特性和姿态控制是研究重点。本文建立水下航行器垂直面航行运动模型,分析高速航行下的运动特性。为保证高速航行高效稳定,提出PID方法控制纵倾和滑模方法控制深度的组合控制策略。通过仿真试验,开展高速航行运动仿真研究。研究结果表明,在高速航行下,水下航行器会产生一定纵倾,且随着航速增加,纵倾影响会越大,高速状态放大了水下航行器外形上下轻微不对称的特性,诱导产生的垂向水动力及力矩增大,进而引起纵倾;在高速航行条件下,水下航行器能稳定保持定深度长距离航行,控制策略具有很好的适用性。

水下无人航行器实时轨迹跟踪控制方法研究

针对水下无人航行器受外界不确定因素影响产生航行准确度低的问题,研究水下无人航行器实时轨迹跟踪控制方法。分析水下无人航行器运动特性,设计基于贝叶斯神经网络的水下无人航行器自适应控制器,以水下无人航行器的参考速度信号为网络输入,通过网络的不断训练,输出控制力矩,促使水下无人航行器的航行点与预设航行位误差趋近于0,完成实时轨迹跟踪控制。实验结果表明,该方法可完成直线轨迹、圆形曲线轨迹的跟踪控制,且航行点与预设航行位误差小、收敛快、波动次数少,具备轨迹跟踪控制抗干扰能力强、适应能力强的优势。

基于强化学习的激光导航无人车路径跟踪控制

针对智能仓储无人车运动轨迹控制精度的问题,提出了一种基于强化学习的激光导航无人车路径跟踪控制算法。建立了智能仓储无人车的数学模型,设计了一种激光导航定位算法,提出了一种Actor-Critic强化学习路径跟踪算法,最终实现对无人车路径跟踪的高精度控制。通过对比仿真验证了设计的路径跟踪算法具有更优的控制效果和更高的控制精度,最大路径跟踪误差仅为0.3 m,最大x坐标跟踪误差仅为0.1 m,最大y坐标跟踪误差仅为0.29 m,大幅提高了对仓储无人车运动轨迹的跟踪精度。

基于毫米波雷达的智能车辆主动避障控制系统设计

智能车辆所搭载监测设备对障碍物目标的识别准确性,影响行驶车辆的避障能力;为避免车辆与障碍物发生碰撞,提升智能车辆的避障能力,设计基于毫米波雷达的智能车辆主动避障控制系统;在底层控制单元中,按需连接纵横向导航控制元件与毫米波雷达摄像头,完成智能车辆主动避障控制系统的部件结构设计;利用毫米波雷达监测所得的车辆避障图像,定义空间坐标系转换条件,通过标定雷达相机参数的方式,实现基于毫米波雷达的智能车辆避障路径规划;建立车辆纵横向运动模型,根据避障安全距离计算结果,完善具体控制流程,联合各级硬件应用结构,完成基于毫米波雷达的智能车辆纵横向主动避障控制系统的设计;实验结果表明,所设计系统可在智能车辆通过障碍物目标时,保证车体与障碍物之间的距离大于0.3 m,能够避免碰撞行为发生,对于车载监测设备而言,其对于障碍物目标的准确识别能力得到了保障,能够有效提升智能车辆避障能力。

Cascaded navigation control for agricultural vehicles tracking straight paths

In precision agriculture(PA),an agricultural vehicle navigation system is essential and the navigation control accuracy is important in this system.As straight path tracking is the major operating mode of agricultural vehicles on large fields,a cascaded navigation control method for straight path tracking is proposed in this study.Firstly,a cascaded navigation control structure for the agricultural vehicle was discussed.Based on this structure,the navigation control task was decomposed into two cascaded control tasks,namely,the path tracking control task and the steering control task.Secondly,a relative kinematics model of agricultural vehicles was deduced,and an optimal Proportional-Derivative(PD)method based on the deduced model was developed in the path tracking control task.Then,an improved PD method based on a transition process was proposed in the steering control task to enhance the performance of the steering control subsystem.Finally,the effectiveness and the superiority of the proposed method were verified by a series of experiments.Results of the experimental data analysis show that mean value of the lateral position deviation is 0.02 m and standard deviation of the lateral position deviation is 0.04 m,which proves that the proposed method has achieved satisfactory effects on the straight path tracking of agricultural vehicles.

Development of autonomous navigation controller for agricultural vehicles

Agricultural vehicles are adopted to undertake farming tasks by traversing along crop rows in the field.Working quality depends significantly on the driving skills of the operator.Automatic guidance has been introduced into agriculture to achieve high-accuracy path tracking during the last decades,which contributes considerably to straight-line navigation.The objective of this research was to develop an autonomous navigation controller that allowed movement autonomy for various agricultural vehicles.Three wheel-type vehicles were used as the test platform featuring automatic steering,hydrostatic transmission and speed control,which included a rice transplanter,a high-clearance sprayer and a tractor.A dual-antenna RTK-GNSS receiver was attached to the vehicles to provide spatial information on both positioning and heading by using the RTX service from Trimble.A path planning method was proposed to create a straight-line reference path by giving two points,and the target path was determined according to the vehicle initial status and working assignment.Headland turning was comprehensively taken into account by listing different turn patterns in order to realize autonomous navigation at the headland.The navigation controller hardware was fabricated for program execution,data processing and information communication with peripherals.A human-machine interface was designed for the operator to complete basic setting,path planning and navigation control by providing controls.Field experiments were conducted to evaluate the performance and versatility of the newly developed autonomous navigation controller in guiding agricultural vehicles to follow straight paths and turn at the headland.Results showed that an appropriate turn pattern was automatically executed when finishing straight-line navigation.The lateral error in straight-line tracking was no more than 6 cm,6 cm and 5 cm for the rice transplanter,the high-clearance sprayer and the tractor,respectively.And the maximum lateral RMS error was 3.10 cm,4.75 cm,2.21 cm in terms of straight-line tracking,which indicated that the newly developed autonomous navigation controller was versatile and of high robustness in guiding various agricultural vehicles.

Cooperative Search and Task Allocation Among Heterogeneous Teams of UAVs

A cooperative control method of multi-class UAV(unmanned air vehicle) team is investigated.During the mission,the UAVs perform search,classification,attack and battle damage assessment(BDA) tasks at various locations,which involves a combination of the team intelligence type of decision making combined with control,estimate and real-time trajectory optimization.The search-theoretic approach based on rate of return(ROR) maps is developed to get the cooperative search strategy.Templates are developed and views are combined to maximize the probability of correct target identification over various aspect angles.Monte Carle simulation runs for the scenario to evaluate the performance of the approach with various decision parameters,UAVs distributions and UAV team characteristics.Simulation results show that the cooperative behavior can significantly improve the operational effectiveness of UAV team,and the cooperative control allows for near optimal solution of the correlative behavior of a group of UAVs in battlefield.

自主水下航行器协同控制研究现状与发展趋势

自主水下航行器(AUV)的协同控制作为海洋开发和多机器人系统之间的交叉领域,近几十年来越来越受到研究人员和工程师的关注。目前,AUV协同控制理论体系尚处于构建之中,相关研究正面临诸多亟待解决的难题。文中对多AUV协同控制问题中的编队控制、协同导航和定位、协同路径规划、任务分配以及目标围捕等研究进行了全面调研,同时分析了编队控制的网络架构、协同策略以及其面临的约束等问题。最后讨论了未来可能研究的相关方向,为在复杂的海洋应用场景中合理利用AUV来完成各种水下任务提供相关参考。

潜航器水声通信导航定位一体化技术进展

为了改善潜航器通信和导航定位作为独立载荷时在信息交互、带宽利用率、资源限制等方面的劣势,研究了基于水声的通信导航定位一体化技术。借鉴雷达一体化的发展历程;通过梳理水声通信导航定位一体化的研究成果,结合声呐应用背景,分析了声呐一体化的发展趋势;针对潜航器集群中的基础问题,研究了系统结构的一体化和信号体制2个关键点;最后,在潜航器多用户集群编队、水下测控和靶场建设2个方面进行了应用展望。通过分析阐述,可为未来声呐技术向集成化、一体化发展提供新方法和新思路。

基于虚拟探照灯的离合制动履带底盘寻径跟踪

油动履带底盘由于具有成本低、技术成熟、动力充足、续航能力强、维修便捷等特点而被广泛应用于农业生产,但其操控精度低、振动严重等问题对其应用造成挑战。该研究以农用油动履带底盘为对象,根据共性传动结构提出离合制动式履带底盘,并以STM32F303作为主控器搭建基于实时动态差分全球导航卫星系统(real-time kinematic global navigation satellite system,RTK-GNSS)的自动导航系统,建立其运动学模型,提出一种改进模糊式预瞄控制算法—虚拟探照灯寻径跟踪(virtual searchlight pathfinding tracking,VSPT)算法。针对横向偏差和速度变化引起的跟踪振荡问题,提出基于横向偏差指数的视域角动态调整方法和基于行驶速度的虚拟目标点判断方法,并通过仿真和试验验证算法的有效性。仿真结果表明,在底盘前进速度0.4 m/s时,横向偏差指数λ、视域增益k1和目标增益k2取值分别为1/4,0.005 rad·m和6 s^(-1)时可获得较好的导航效果。现场试验结果表明,在水泥路面,不同初始位姿下,直线导航平均上线距离为1.64 m,平均横向偏差和航向偏差为0.44 cm和1.57°;行驶速度提高会导致导航精度降低,适当修正k1、k2可维持较好的导航效果,3种行驶速度下获得的平均横向和航向偏差分别为0.75 cm和1.05°,平均纠偏次数为4.7次;田间路况下,由于土路附着系数增加,转向相对平稳,纠偏次数降低至2.7次,相同参数时2种路况下的导航效果接近。研究表明,VSPT算法针对离合制动式履带底盘具有良好的跟踪效果和路况适应性,该研究可为离合制动履带平台提供一种高效、稳定的导航控制方案。

面向回收任务的无人艇自适应级联跟踪控制

[目的]针对当前艉滑道式回收技术中的高精度回收引导控制要求,提出一种面向艉滑道回收的无人艇(USV)自适应级联跟踪控制方法。[方法]建立欠驱动无人艇运动模型,基于艉滑道式回收技术要求,利用滤波算法实现对母船航行状态和回收位姿的预测;引入平行接近制导思想,结合滑模变结构控制理论,构建出稳定的级联控制系统,以解决无人艇回收过程中的跟踪控制问题。[结果]通过采用李雅普诺夫理论和级联定理分析系统的稳定性,证明无人艇能够稳定跟踪目标。[结论]仿真结果表明,所提控制方法可使无人艇具有稳定的跟踪性能,且对不确定性干扰表现出较强的鲁棒性。

基于车道级导航的应急车辆信号优先控制研究

文中基于车道级导航系统,构建了车道级应急车辆优先协调控制系统,利用预信号与主信号协调配时,提出应急车辆在大型交叉口的优先通行信号控制方法.利用VISSIM进行模拟实验,对比分析在不同信号控制方法下应急车辆通过交叉口的实际运行数据.结果表明:车道级导航下的应急车辆信号优先控制能显著提高应急车辆在交叉口的通行效率.

矿井无轨胶轮车智能化管理系统研究

针对煤矿井下工作地点分散、运输路线复杂、巷道内弯道和交叉路口较多的特点与煤矿智能化建设的需要,从需求分析、系统架构、关键技术等方面对矿井无轨胶轮车智能化管理系统进行了研究。通过需求分析,得出矿井无轨胶轮车智能化管理系统需具有矿井车辆精准定位、矿井车辆工况信息实时采集、矿井车辆移动通信、矿井车辆智能导航、矿井车辆状态实时监测与控制、矿井车辆防碰撞预警等功能。对系统关键技术进行了详细介绍:分析了UWB定位技术在矿井无轨胶轮车定位中的应用;提出矿井车辆移动通信技术宜采用WiFi与4G/5G技术;讨论了常用路径规划技术的特点,得出矿井无轨胶轮车导航技术宜采用成熟度较高的基于图搜索的路径规划算法,矿井无轨胶轮车导航和轨迹回放技术应与GIS技术相结合;研究了矿井车辆红绿灯控制技术,提出了十字交叉口模型和单车通行巷模型;研究了车辆防碰撞预警技术,根据行人和车辆位置及其与UWB基站的相对方向和距离,分析了同基站与跨基站2种模式下的防碰撞预警原理。实验结果表明,基于UWB的矿井车辆通信、基于A*算法的矿井车辆路径规划及轨迹回放、红绿灯控制、防碰撞预警等功能均能满足应用需求。