Cooperative Controller Design Of Vertical Takeoff And Landing Aircrafts Based On Regulation Theory

Vertical takeoff and landing(VTOL)aircrafts,as one of the most popular type of aircrafts,has attracted wide attention in both military and civilian fields,as well as in scientific research fields.This kind of aircraft has the characteristics of nonlinearity,strong coupling and multiinput and multi-output(MIMO),so the control of this kind of aircraft is difficult.Based on the simplified model of VTOL aircrafts,following the general method of nonlinear output regulation,we complete the design of landing control algorithm for this kind of aircraft.In this paper,the kinematics model is analyzed and the influence of disturbance at both ends of the wingtips on the model is considered.Aiming at the non-static situation of landing platform,such as the oscillating deck of a ship due to sea waves,the trajectory tracking and disturbance rejection algorithm is designed based on internal model approach to achieve the smooth landing of aircraft.The algorithm has good robustness to parameters uncertainties and external disturbances.Then,for the case of multi-aircraft cooperative landing,based on directed graph communication topology and consensus theory,a cooperative formation control algorithm is designed to realize formation tracking and landing control of multi-aircraft.Specifically,the main work of this paper is as follows:First,kinematics modeling is completed based on the force analysis of VTOL aircraft,and the landing problem of such aircraft is considered.The landing problem of such aircraft on an oscillating platform is transformed into the problem of trajectory tracking and disturbance rejection.Then,based on the general method of dealing with the output regulation problem,the internal model dynamics design and the stabilization controller design are completed respectively.The augmented system which is composed of the aircraft system and the internal model dynamics is regarded as a feedback interconnection structure of the subsystem consisting of vertical and internal model dynamics and the subsystem consisting of horizontal,angular and internal model dynamics.By designing appropriate controllers,both subsystems have certain input-to-state stability(ISS).Then small gain theorem is further used to analyze the stability of the whole system.Second,the above results are extended to the cooperative landing control of multiple aircrafts.Considering the cooperative landing control of a group of heterogeneous VTOL aircrafts,based on the consensus theory,the landing platform is regarded as the leader and the other aircrafts are regarded as the followers.The directed graph communication topology strategy is adopted to interact the relative position information between the aircrafts,and two kind of cooperative control algorithms,distributed robust cooperative controller and adaptive distributed observer based cooperative controller,are designed respectively.The designed cooperative control algorithms can make the aircrafts follow the landing platform in a certain formation,and achieve smooth landing when the tracking and formation task are completed.The designed control algorithms have good robustness to the uncertainties of aircraft parameters.Finally,the cooperative control experiments of a group of VTOL aircrafts based on the open source quadrotor platform and indoor motion capture system are completed.The effectiveness of the cooperative control algorithms is verified.By comparing with the results under the PID control algorithm,the advantages in aspect of steady-state tracking accuracy of the cooperative control algorithms designed in this paper are demonstrated.