Research On Automatic Takeoff And Landing Control Technology For Unmanned Helicopter

Automatic takeoff and landing is one of the most important functions of unmanned helicopterautomatic fly control system，impacts the engineering application level of the unmanned helicopterdirectly. With the research project on a small unmanned helicopter as the background, the automatictakeoff and landing control system is developed by the research on the relevant control technologiesincluding dynamic modeling, control law designing and automatic takeoff and landing strategyestablishing.The thesis proposes a new predigest method which calculates the induce velocity throughinvestigating the downward trailed wake and describes the flap movement by dynamic balance tomodel the rotor. This method gets good balance between calculate precision and complexity. Then, thestability and the maneuverability of the dynamic model are analysed as the base for control lawdesign.The longitudinal and lateral channels of helicopter are the key points of control law designbecause of the unstable and coupling. According to the physical characters and control requirementduring takeoff and landing flight, this thesis presents a control strategy, which use inner/outer loopstructure. The inner loop augments the stability by attitude damping, the outer loop controls thevelocity when floating on the ground and controls the position when in the sky. The forwardautomatic trim and nonlinear control method are put forward to improve the adaptability ofaugmentation loop and control precision of position control loop.Base on the single channel control law，the automatic takeoff and landing strategy which solvesthe problems such as leave ground adaptability, slippage restraining, safety problem and highprecision position control and so on, is made to realize the automatic takeoff and landing function.Half physical real-time simulation and fly test are used to verify the automatic takeoff andlanding control system. The simulation and the fly result shows that, the dynamic model expresses thephysical characters of the helicopter well, the control law and the automatic takeoff and landingstrategy have good control effect, and the control system can implement automatic takeoff and landingof unmanned helicopter successfully.