对地面目标的自动跟踪是无人机在任务应用阶段需要解决的重要问题之一，多无人机协同跟踪能够提高对目标运动状态的估计精度并降低目标丢失的概率，因而具有重要研究意义。本文提出了一种基于Leader-Follower编队的无人机协同跟踪制导方法，解决了传统Standoff跟踪模式对地面目标的速度范围限制问题。首先，通过控制无人机的航向不断趋近于地面目标牵连跟踪圆切线方向的方法设计了Leader无人机自动跟踪地面目标的制导律并完成了稳定性证明；其次，通过控制Follower无人机的速度和航向角逐渐趋近于Leader无人机速度和航向的协同跟踪策略，分别设计了Follower无人机自动跟踪Leader无人机的制导律和编队相位协同制导律并完成了稳定性证明；最后，分别针对静止目标、匀速直线运动目标和变速运动目标的跟踪问题进行了仿真验证，结果表明所提出的制导方法能够实现对不同运动状态地面目标的自动协同跟踪，并且跟踪性能优于基于李雅普诺夫向量法的制导方法。
Ground target tracking is one of the important issues for Unmanned Aerial Vehicles (UAVs) in the mission application stage. Multi-UAV cooperative tracking can reduce the probability of losing the target and improve the estimation accuracy. This paper presents a method of guidance law for cooperative tracking based on leader-follower formation of UAVs, which solves the problem of speed range limitation of traditional standoff tracking method. By controlling the heading of the leader UAV in approaching the tangential direction of the tracking circle, a new guidance law for the leader UAV is designed, and the close-loop system stability of the law is proved. By controlling the speed and heading of the follower UAV in approaching the speed and heading of the leader UAV, new guidance laws for tracking of the leader UAV and controlling of the inter-UAV angle of the formation are designed for the follower UAVs, and the stability of the laws are also proved using two Lyapunov functions. Simulation results of tracking the static target, the constant speed target and the variable speed target show that the proposed guidance method can achieve the cooperative tracking of the ground targets with different motions, and the tracking performance is better than the classic Lyapunov vector method under the same simulation conditions.
[1] 陈宗基, 魏金钟, 王英勋, 等. 无人机自主控制等级及其系统结构研究[J]. 航空学报, 2011, 32(6):1075-1083. CHEN Z J, WEI J Z, WANG Y X, et al. UAV autonomous control levels and system structure[J]. Acta Aeronautica et Astronautica Sinica, 2011, 32(6):1075-1083(in Chinese).[2] 王道波, 王寅, 蒋琬玥, 等. 基于化学反应优化的多无人机地面移动目标协同观测航迹规划[J]. 中国科学(技术科学), 2015, 45(6):583-594. WANG D B, WANG Y, JIANG W Y, et al. Unmanned aerial vehicles cooperative path planning for ground target tracking via chemical reaction optimization[J]. Scientia Sinica (Technologica), 2015, 45(6):683-594(in Chinese).[3] RATHINAM S, ZU W K, SENGUPTA R. Vision-based monitoring of locally linear structures using an un-manned aerial vehicle[J]. Journal of Infrastructure Systems, 2008, 14(1):52-63.[4] LIU W, ZHENG Z, CAI K Y. Adaptive path planning for unmanned aerial vehicles based on bi-level programming and variable planning time interval[J]. Chinese Journal of Aeronautics, 2013, 26(3):646-660.[5] BERTUCCELLI L F, HOW J P. Search for dynamic targets with uncertain probability maps[C]//American Control Conference. Piscataway, NJ:IEEE Press, 2006:14-16.[6] LI Z Y, HOVAKIMYAN N, DOBROKHODOV V, et al. Vision-based target tracking and motion estimation using a small UAV[C]//49th IEEE Conference on Decision and Control. Piscataway, NJ:IEEE Press, 2011:2505-2510.[7] 齐雪, 张利军, 赵杰梅. Serret-Frenet坐标系下AUV自适应路径跟踪控制[J]. 系统科学与数学, 2016, 36(11):1851-1864. QI X, ZHANG L J, ZHAO J M. Advanced path tracking control of AUV in Serret-Frenet coordinate system[J]. Journal of Systems Science and Mathematical Sciences, 2016, 36(11):1851-1864(in Chinese).[8] SHAMES I, DASGUPTA S, FIDAN B, et al. Circumnavigation using distance measurements under slow drift[J]. IEEE Transactions on Automatic Control, 2012, 57(4):889-903.[9] YAMASAKI T, BALAKRISHNAN S N. Sliding mode based pure pursuit guidance for UAV rendezvous and chase with a cooperative aircraft[C]//American Control Conference. Piscataway, NJ:IEEE Press, 2010:5544-5549.[10] MATVEEV A S, TEIMOORI, H, SAVKIN A V. The problem of target following based on range-only measurements for car-like robots[C]//IEEE conference on decision and control and Chinese control conference. Piscataway, NJ:IEEE Press, 2009:8537-8542.[11] MATVEEV A S, TEIMOORI, H, SAVKIN A V. Range-only measurements based target following for wheeled mobile robots[J]. Automatica, 2011, 47(1):177-184.[12] SUMMERS T, AKELLA M, MEARS M. Coordinated standoff tracking of moving targets:Control laws and information architectures[J]. Journal of Guidance, Control, & Dynamics, 2013, 32(1):56-69.[13] VARGA M, ZUFFEREY J C, HEITZ G, et al. Evaluation of control strategies for fixed-wing drones following slow-moving ground agents[J]. Robotics and Autonomous Systems, 2015, 72(1):285-294.[14] CHEN B H, JIAO Z X, SHUZHI S G. Aircraft-on-ground path following control by dynamical adaptive backstepping[J]. Chinese Journal of Aeronautics, 2013, 26(3):668-675.[15] 吴森堂, 费玉华. 飞行控制系统[M]. 北京:北京航空航天大学出版社, 2005:46-64. WU S T, FEI Y H. Flight control system[M]. Beijing:Beihang University Press, 2005:46-64(in Chinese).[16] LI Z, HOVAKIMYAN N, DOBROKHODOV V, et al. Vision-based tracking and motion estimation for moving targets using small UAVs[C]//American Control Conference. Piscataway, NJ:IEEE Press, 2006:1428-1433.[17] ZHAO Q L, DONG X W, LIANG Z, et al. Distributed cooperative guidance for multiple missiles with fixed and switching communication topologies[J]. Chinese Journal of Aeronautics, 2017, 30(4):1570-1581.[18] KHALIL H K. Nonlinear systems[M]. 3rd ed. Upper Saddle River, NJ:Prentice Hall, 2002:111-174.[19] ZHANG M, LIU H. Cooperative tracking a moving target using multiple fixed-wing UAVs[J]. Journal of Intelligent and Robotic Systems, 2016, 81(3):505-529.[20] FREW E W, LAWRENCE D A, STEVE M. Coordinated standoff tracking of moving targets using Lyapunov guidance vector fields[J]. Journal of Guidance, Control, & Dynamics, 2008, 31(2):290-306.
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