Citation: Zhan, G.; Gong, Z.; Lv, Q.;
Zhou, Z.; Wang, Z.; Yang, Z.; Zhou, D.
Flight Test of Autonomous Formation
Management for Multiple Fixed-
Wing UAVs Based on Missile Parallel
Method. Drones 2022, 6, 99. https://
doi.org/10.3390/drones6050099
Academic Editors: Andrzej
Łukaszewicz, Andriy Holovatyy,
Wojciech Giernacki, Jarosław Pytka
and Zbigniew Kulesza
Received: 14 March 2022
Accepted: 13 April 2022
Published: 19 April 2022
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Article
Flight Test of Autonomous Formation Management for
Multiple Fixed-Wing UAVs Based on Missile Parallel Method
Guang Zhan
1,
* , Zheng Gong
2
, Quanhui Lv
2
, Zan Zhou
2
, Zian Wang
2
, Zhen Yang
1
and Deyun Zhou
1
1
School of Electronics and Information, Northwestern Polytechnical University, Xi’an 710072, China;
nwpuyz@mail.nwpu.edu.cn (Z.Y.); dyzhou@nwpu.edu.cn (D.Z.)
2
Department of Aerospace Engineering, College of Aerospace Engineering,
Nanjing University of Aeronautics and Astronautics, Nanjing 210095, China;
matthewzhenggong@nuaa.edu.cn (Z.G.); quanhui.lv@nuaa.edu.cn (Q.L.); zhouzan@nuaa.edu.cn (Z.Z.);
wangzian@nuaa.edu.cn (Z.W.)
* Correspondence: zhanguang@mail.nwpu.edu.cn
Abstract:
This paper reports on the formation and transformation of multiple fixed-wing unmanned
aerial vehicles (UAVs) in three-dimensional space. A cooperative guidance law based on the classic
missile-type parallel-approach method is designed for the multi-UAV formation control problem.
Additionally, formation transformation strategies for multi-UAV autonomous assembly, disbandment,
and special circumstances are formed, effective for managing and controlling the formation. When
formulating the management strategy for formation establishment, its process is divided into three
steps: (i) selecting and allocating target points, (ii) forming loose formations, and (iii) forming short-
range formations. The management of disbanding the formation is formulated through reverse
thinking: the assembly process is split and recombined in reverse, and a formation disbanding
strategy that can achieve a smooth transition from close to lose formation is proposed. Additionally,
a strategy is given for adjusting the formation transformation in special cases, and the formation
adjustment is completed using the adjacency matrix. Finally, a hardware-in-the-loop simulation and
measured flight verification using a simulator show the practicality of the guidance law in meeting
the control requirements of UAV formation flight for specific flight tasks.
Keywords: formation management; missile parallel method; flight test
1. Introduction
Form formation management is an important research topic for multiple unmanned
aerial vehicles (UAVs) flying in cooperative formation [
1
,
2
]. Because of the limited control
of fixed-wing UAVs, their formation management is very different from that of quadro-
tor UAVs. By contrast, static and fixed-wing UAVs cannot wait for other UAVs during
formation [3], which makes stable and reliable formation challenging.
In recent decades, many scholars have researched the formation of fixed-wing UAVs.
Zhang [
4
] proposed a proportional integral–derivative (PID) integrated control method
based on robust control; this comprehensive control method improves the hit rate and
flight stability of UAV formation, reduces the dynamic response of the steady-state error,
and shortens the convergence time, but the influence of the coupling effect of the integrated
controller on the entire control system was not considered in the corresponding experi-
ment. Kada [
5
] proposed (i) a smooth distributed cooperative control method for multiple
aircraft (such as UAVs) based on multi-agent system (MAS) consistency and
(ii) a smooth
distributed consistency algorithm, as well as designing a formation control model for
three-dimensional (3D) geometry tracking; however, the disadvantage of this approach
is that it fails to consider (i) formation tracking in the case of external interference and
(ii) obstacle avoidance
among flying agents. Wang [
6
] analyzed the optimality of formation
configuration, provided an optimal formation design strategy for multi-UAV patrol tasks,
Drones 2022, 6, 99. https://doi.org/10.3390/drones6050099 https://www.mdpi.com/journal/drones
