A Study On The Automatic Landing Of Quadrotor

Quadrotors can take off and land vertically,hover at a fixed point,fly at an extremely low speed,and are capable for tasks under various complex conditions.The quadrotors has the advantage of simple structure,reliable performance and convenient maintenance.Therefore,the electric quadrotor scheme experienced rapid development since its first success in 2006.Recently,the flight control technique of a single quadrotor has been well-developed.Hence,the study of automatic landing,formation and returning flight plays an increasingly important role in the improvement of the practicability and reliability of quadrotors.Based on researches of the automatic control of a single quadrotor,this thesis proposes a comprehensive solution to achieve the goals of returning,approach and landing in varied scenarios.The research contents include:1,Modeling of quadrotors and the constraints in returning,approach and langding.A nonlinear model of quadrotors is developed and the dynamics are analyzed.The constraints and requirements are derived in accordance with practical conditions of approach and landing,which is instructive for the design of control law for approach and landing of quadrotors.2,Approach and landing on a fixed platform of a single quadrotor.The static platform landing is one of the most common cases for quadrotors.The route is generated by a few preseted waypoints,the navigation information is provided by Global Navigation Satellite System(GNSS),barometer and SINS,combined with the automatic approach and landing control law,the fixed platform landing of a single quadrotor is achieved.3,Moving platform approach and landing of a single quadrotor.For the moving platform approach and landing of a ship-based quadrotor,platform-quadrotor communication system was established to transmit the real-time motion information to address the problem of limited payload and information perception ability of quadrotors.The moving platform landing for a single quadrotor is achieved by a approach and landing control law.4,Formation returning and approach to fixed platform of quadrotors.UAVs’ formation,coordination and cluster is an important subject and development trend.Quadrotors’ formation technique will play an important role in pesticide spraying,regional real-time monitoring and other applications.For quadrotors’ formation approach and returning,this thesis introduced a solution to the communication and control problem of quadrotors’ formation flight.Based on the distributed leader-follower control scheme,a solution to the automatic sparse formation returning and approach control problem is developed.Eventually,the practicability of the proposed scheme has been proved by both simulations and flight experiments.Especially in flight experiments,the experimental results are consistent with the simulation.The hardware and software platforms are simple,reliable,and easy to practice.In general,the proposed scheme is of good practicability.