Dynamic Modeling And Simulation Analysis Of Helicopter With Variable Speed Rotor

The wide application of helicopters has put forward higher requirements for the performance of helicopters.The concept of variable rotor rotor has come into being.By reducing the rotor speed,improve the helicopter speed,the maximum ceiling,reduce the required power,reduce fuel consumption,increase voyage voyage,flight envelope expansion,is a major breakthrough in the development of the helicopter.At the same time,the change of rotor speed also brings some problems,such as the change of the rotor vibration load.The rotor speed is reduced,and the air flow asymmetry on both sides of the paddle is aggravated,and the vibration problem is more prominent.This paper established the flight dynamics model of helicopter,and the Black Hawk helicopter as the research object,the rotor aerodynamic blade element theory as the foundation,considering the effect of reverse flow region,combined with the fuselage,tail rotor,horizontal and vertical tail model,the whole machine balancing helicopter,flight test data and comparison with Black Hawk helicopters to do to verify the accuracy of flight mechanics model.On this basis,the change law of the helicopter control and attitude angle is studied by reducing the rotational speed of the rotor model.Besides,the paper calculates the required power of Black Hawk helicopters,summarizes and concludes the changing rule of helicopter power consumption under variable speed conditions,and discusses and analyzes the reasons.This paper studies the vibration load of the helicopter.It is necessary to establish the dynamic model of pneumatic structure coupling,with blade structure model established based on large deformation beam model and aerodynamic model based on linear flow,viscous vortex particle method and two-dimensional unsteady aerodynamic model.Then dynamic equations were derived by Hamilton variational principle.In the aspect of load calculation,the method combining inverse force method with force integral method is used.The gazelle helicopter was taken as an example to verify the accuracy of the calculation method of dynamics model.Finally,the rotor vibration load of Black Hawk helicopter is calculated under the condition of variable speed,and the variation rule of blade vibration load is studied and analyzed.