Cooperative Control Of Multiple UAVs With Actuator Saturation

Saturation nonlinearity exists in every practical control system and makes the overall system inherently nonlinear.Ignoring saturation nonlinearity in the controller design may lead to performance degradation and even instability of the closed-loop system.Therefore,the study of control systems with actuator saturation is significant in theory and applications.In recent years,Unmanned Aerial Vehicle(UAV)has getting more and more attention for their high robustness,self adaptability and flexibility.The control of the system of UAV with saturation are studied in this paper.The main works are listed as follows:Firstly,a low gain feedback control approach is proposed in this paper for the vertical takeoff and landing vehicles system with saturation constraint based on the parametric Lyapunov equation.First,the general model of vertical takeoff and landing vehicles system is introduced.After that,simplified the complex general model into four independent subsystems.A continuous low gain feedback controller is designed for position subsystem with saturation constraint.The proposed approach improves the dynamic performances of the closed-loop systems significantly by gradually increasing a design parameter representing the convergence rate of the closed-loop system.Secondly,semi-global consensus of multiple vertical takeoff and landing vehicles with saturation constraint is considered.The simplified multiple vertical takeoff and landing vehicles is obtained by using the theory of nonautonomous cascaded systems.Then the consensus for such systems can be solved by utilizing the parametric Lyapunov equation.The low gain feedback matrix can be obtained by means of the positive definite solution of the parametric Lyapunov equation.Under the proposed low gain controller,the whole multiple vertical takeoff and landing vehicles system with actuator saturation can reach semi-global consensus.Thirdly,global consensus control and formation control of multiple VTOL vehicles with saturation constraint is considered.Introduced the hyperbolic tangent function according to the boundedness of the hyperbolic tangent function for the model with cascade form in design of the formation controller.Finally,the formation control algorithm is presented based on the proposed consensus algorithm with input constraint to study the problem of multiple UAVs formation control.