Research On Finite-time Attitude Cooperative Control Methods For Aircraft

As we all know,multiple aircraft cooperation can make up for the shortcomings of single aircraft to accomplish tasks efficiently and stably,therefore,multiple aircraft cooperative flight has attracted more and more scholars’ attention.In the research of multiple aircraft cooperative flight technology,fast attitude estimation and fast attitude cooperation are the research focus.In the complex environment,the disturbance of the external environment,attitude sensor performance,and communication device performance will affect the stability of the aircraft attitude cooperative.Meanwhile,in the face of some special tasks,multiple aircraft systems need to quickly attitude adjustment complete attitude cooperation.Therefore,aircraft attitude information demand rapid acquisition and attitude coordination stability control in finite time,response to task efficiently and reliably.From the perspective of time optimization,this paper investigates aircraft attitude fast solution and attitude quickly coordinated control problem.The research work carried out to improve the aircraft attitude cooperative control method mainly includes four following points:(1)Research on the symbolic attitude determination based on quaternion attitude descriptionIn order to complete attitude cooperative control in real time,each aircraft needs to obtain its own attitude information.At the same time,under the cooperative attitude control strategy,it compares its own attitude information with the target information given by the leader,so as to complete the tracking of individual attitude to the leader’s attitude information.Aircraft attitude determination is the premise of aircraft attitude control.Aiming at how to quickly obtain high-precision attitude information through the limited attitude measurement system of aircraft,a symbolic solution method of attitude determination based on quaternion is proposed.Firstly,in order to avoid gimbal lock problem,the attitude fusion problem is transformed into a set of nonlinear equations based on quaternion.Thirdly,after re-expressing the equations,a new symbolic solution method of attitude determination is proposed.Compared with the existing methods,the results show that the proposed method has higher timeliness performance and lower calculation cost.(2)Research on attitude cooperative strategy based on a new finite-time disturbance observerHow to improve attitude stability and achieve rapid task coordination under the effect of disturbances and parameter uncertainty is an important research content in this paper.Firstly,the quaternion is used as the attitude description method to construct the attitude kinematics equation of the aircraft.A new sliding mode surface is constructed based on the integral sliding mode and the nonsingular terminal sliding mode.The uncertain parameters and external disturbances in the attitude dynamics are defined as the composite disturbance part by transformation.According to the observer theory,a new finite-time disturbance observer is constructed to estimate the composite disturbance part.Through numerical simulation and comparison,the finite-time disturbance observer proposed in this paper can reconstruct the disturbance information in a shorter time.Distributed finite-time cooperative control laws are designed for undirected and directed topology,respectively.Numerical simulation results show that the proposed distributed finite-time controller can ensure the system to achieve attitude cooperative task.(3)Research on finite-time attitude cooperative strategy based on event-driven mechanismIn aircraft cooperative tasks,the communication between aircraft generally adopts fixed sampling mechanism,too many communication frequencies will increase the failure rate of the controller.To solve this problem,the event-driven sampling mechanism is used to construct the communication mechanism between aircraft,and a composite sliding mode surface is constructed through the integral sliding mode and terminal sliding mode.The adaptive neural network method is used to estimate the comprehensive uncertain part of multiple aircraft,and the finite-time attitude cooperative based on event-driven mechanism is realized.The numerical simulation results verify that the attitude coordination technology proposed in this paper can greatly reduce the frequency of the controller,and save the energy of aircraft.(4)Research on fully distributed adaptive fault-tolerant finite-time attitude cooperative strategy with actuator faultsAn adaptive fault tolerant finite-time control strategy based on fault detection and identification is proposed for multiple aircraft with actuator faults.Firstly,aiming at the situation that some followers cannot obtain the leader information,a finite-time observer is designed to estimate the leader information to ensure that all followers can obtain the leader information,avoid the algebraic ring problem of directed topology and reduce the burden of network communication.Secondly,a fault detection and identification strategy is proposed,which detects and identifies partial failure faults and offsets faults through fault observer,and judges the classification of faults through decision function.And then a fully distributed adaptive fault-tolerant control strategy is constructed.Finally,the stability of the systems is verified by theoretical analysis,and the consistency and coordination of attitude in the case of failure is verified by numerical simulation and comparison.