Research On Autonomous Takeoff And Landing Control Of Unmanned Helicopter

Small unmanned helicopters have broad application prospects in both military and civilian fields,attracting the attention and research of scholars all over the world.Autonomous take-off and landing is an important part of their autonomous flight control.The process of taking off and landing is short and the control requirements are high.Manual participation requires the operator to have a wealth of experience,but security is still not guaranteed.Therefore,achieving autonomous take-off and landing is of great significance and is one of the important factors that determine the ability of small unmanned helicopters to fly autonomously.Based on the development of a small unmanned helicopter,this paper completes the automatic take-off and automatic of unmanned helicopters through the research on the dynamics modeling,control law design,automatic take-off landing strategy and other related technologies of unmanned helicopter take-off and landing phases.Design and verification of landing control systems.The first chapter summarizes the research status of small unmanned helicopters at home and abroad,analyzes the research status and progress of control research and autonomous take-off and landing control technology for unmanned helicopters,and discusses the key technologies and difficulties in the process of autonomous take-off and landing.The second chapter summarizes the flight principle of the unmanned helicopter and establishes the nonlinear mathematical model of the system,and simplifies and linearizes the feedback under certain conditions.The nonlinear flight dynamics model of small unmanned helicopters is systematically derived and the processing method of model linearization is given.A state-of-the-art nonlinear model of small unmanned helicopters during take-off and landing was established and linearized using the "small perturbation" method.The entire dynamics model also covers the resistance of the fuselage,the force of the vertical tail and the flat tail and the moment.The third chapter analyzes the aerodynamic characteristics of the unmanned helicopter itself during the take-off and landing phases,and clarifies that the main factor affecting the take-off and landing performance is the external environmental factors,rather than the aerodynamic characteristics of the unmanned helicopter hovering.The design of the control law lays the foundation.The control requirements for the drone when approaching the ground are clarified.Horizontal longitudinal and vertical controllers were designed as required.This proposes a control strategy for autonomous takeoff and landing.Finally,an experimental platform for unmanned helicopters was built.The appropriate unmanned helicopter model was chosen and a flight controller was set up to enable it to control the unmanned helicopter flight.The automatic take-off and landing control system designed by the test flight is verified.The test results show that the established mathematical model can better reflect the dynamic characteristics of the helicopter.The designed control law and automatic take-off landing strategy have better performance.The control effect enables safe take-off and landing of unmanned helicopters.