Typical Fault Estimation and Dynamic Analysis of a Leader-Follower Unmanned Aerial Vehicle Formation

Jian Shen,Pengyun Chen,Xiaoguang Wang,Qingyu Zhu,Giovanni Palmerini

doi:10.1155/2021/6656422

Abstract

In this paper, the typical fault estimation and dynamic analysis are presented for a leader-follower unmanned aerial vehicle (UAV) formation system with external disturbances. Firstly, a dynamic model with proportional navigation guidance (PNG) control of the UAV formation is built. Then, an intermediate observer design method is adopted to estimate the system states and faults simultaneously. Based on the graph theory, the topology relationship between each node in the UAV formation has been also analyzed. The estimator and the system error have been created. Moreover, the typical faults, including the components failure, airframe damage, communication failure, formation collision, and environmental impact, are also discussed for the UAV system. Based on the fault-tolerant strategy, five familiar fault models are proposed from the perspectives of fault estimation, dynamical disturbances, and formation cooperative control. With an analysis of the results of states and faults estimation, the actuator faults can be estimated precisely with component failure and wind disturbances. Furthermore, the basic dynamic characteristics of the UAV formation are discussed. Besides, a comparison of two cases related to the wind disturbance has been accomplished to verify the performance of the fault estimator and controller. The results illustrate the credibility and applicability of the fault estimation and dynamic control strategies for the UAV system which are proposed in this paper. Finally, an extension about the UAV formation prognostic health management system is expounded from the point of view of the fault-tolerant control, dynamic modeling, and multifault estimation.

Highlights

In most developed fields of unmanned aerial vehicle (UAV), formation flight is one of the most important techs in swarm cooperative work
During the flight of the UAV formation, the vehicles may be affected by many factors, such as the actuator jam, airframe damage, communication failure, collisions, or environmental impact
A four-UAV formation is taken as an instance to analyze the dynamics and estimate different types of faults in this part

Summary

Introduction

In most developed fields of unmanned aerial vehicle (UAV), formation flight is one of the most important techs in swarm cooperative work. There are several typical fault diagnosis methods for UAV formation, for instance, distributed fault detection, sliding mode observer, robust unknown input observer, fuzzy sliding mode observer, and neural network In these methods, the observer-based is one of the most used for linear systems with perturbations [2,3,4] and nonlinear systems [5]. Numerical simulations verified that the adjustable range of the followers’ linear velocity was not required to be larger than that of the leaders, which was of significance in the leader-follower formation flight for a large scale of UAVs. in the traditional observer-based fault diagnosis method, the observer matching conditions must be satisfied [13]. The most advantage was that the observer matching conditions and the strict positive realness conditions would not be needed to be satisfied for the systems It was desirable for the fault estimation in the UAV formation system. With the analysis of the results, the future research extensions about the UAV formation fault diagnosis and cooperative control are concluded in the final part

Dynamic Model of the UAV Formation

Typical Fault Models of the UAV Formation

Results and Discussion

Conclusions