Fixed Time Formation Tracking Control Of Multi Quadrotor Uavs Based On Distributed Approach

With the continuous development of scientific and technological level,Quadrotor unmanned aerial vehicles(QUAV)is favored by people from all walks of life with its advantages of low cost,low internal consumption and convenient operation.It is widely used in geological survey,energy search,pesticide spraying and so on.In order to enable QUAV to complete tasks with higher accuracy,the requirements of tracking performance are continuously improved.Moreover,with the increase of task complexity,single QUAV can’t complete the task efficiently or even meet the task requirements due to its load capacity and cruising ability.Therefore,QUAVs formation control has become a very meaningful research topic.In the begining,this paper studies the tracking control for a QUAV,and then studies the formation tracking control of the multi-QUAV Based on the distributed formation control method.The specific research contents are as follows:Firstly,aiming at the tracking control problem of a QUAV under the external disturbance and asymmetric output error constraints,a fixed time controller is designed.An asymmetric tangent barrier Lyapunov function is applied to solve the output error constraints problem of the QUAV,and the external disturbance is estimated by a fixed time disturbance observer,so that the disturbance estimation error converges to zero in fixed time.According to Lyapunov stability theory,the fixed time stability of the system is proved,and the effectiveness of the controller is verified by simulation.Secondly,for the multi-QUAV system under the influence of external disturbance and the initial tracking errors don’t meet the constraints,a fixed time sliding mode disturbance observer is designed based on the non-singular fast terminal sliding mode theory.Combining the translation function and performance function,a distributed formation tracking error conversion form is constructed,which transforms the asymmetric output error constraint problem into a new error signal bounded problem.On this basis,a distributed fixed time formation tracking controller is designed.Using the fixed time stability theory,it is proved that the formation tracking error converges to the constraint range in a fixed time.The effectiveness of the proposed control strategy is verified by simulation.Finally,a fixed time formation control strategy based on neural network is designed for the QUAVs formation system with external interference,time-varying load and input delay.The auxiliary system is introduced to deal with the input delay problem,and the radial basis function neural network is used to approximate the uncertainty caused by time-varying load in the system.At the same time,in order to eliminate the influence of filtering error,the error compensation signal is designed.Based on Lyapunov stability theory,the fixed time stability of the closed-loop system is proved,and the effectiveness of the controller is verified by simulation.