Modeling And Control Of Composite Coaxial High-speed Helicopter

Composite coaxial high-speed helicopter has many advantages such as high-speed flight and vertical takeoff and landing,which make it a broad application prospects in many fields.However,complex dynamic model and control redundancy become the key points of the helicopter This paper focuses on analyzing the dynamic characteristics of CCHSH,establishing mathematical models,and designing the all-inclusive flight control law.Firstly,aiming at the special configuration of the helicopter,the complex aerodynamic layout and cross-coupling are analysis,and the non-linear mathematical model of the helicopter is established,including the aerodynamic model of the airframe components,the brandishing motion equation of two-wing blades and the non-linear full motion equation of the coaxial helicopter.Secondly,the control modes of the helicopter are divided into three modes: hover/low speed mode,transition mode and high-speed mode.Considering the stability and optimal propulsion power,the transition mode and high-speed mode control allocation strategy are designed.Then the model of the helicopter at different forward flight speeds are trim.After that,the small perturbation linearization analysis of the helicopter are carried out through the results of trim.Thirdly,the actuator efficiency allocation mechanism of two control mechanisms is deeply studied,three kind of mode control laws are designed respectively,and a kind of high-speed mode trajectory tracking guidance with L1 guidance is designed.Then aiming at the sudden change of control caused by mode switching,the method of inertia link mode switching is adopted to realize automatic switching of three modes of full envelope.The simulation results show that the designed control laws can effectively and steadily realize the full envelope flight control.Finally,a robust dual-loop disturbance rejection controller is designed for low-altitude low-speed flight mission.The simulation results show that the robust controller designed can effectively suppress the disturbance.Aiming at the obstacle avoidance problem during high-speed grounding flight,a large maneuvering flight controller with response speed as target is designed,which combine the re-planning with guide angle obstacle avoidance technology.The simulation results show that the obstacle avoidance strategy ensuring an excellent and high practicability of flight.