| With the development of science and technology,people continue to explore various flight method,so various functional aircraft came into being.The human-powered bird-inspired aircraft is a kind of human-powered aircraft designed by simulating the flight mechanism of birds.Because of its unique driving method,it has broad application prospects in the fields of amusement project,high-altitude escape and so on.The prototype of the traditional human-powered aircraft has three flight modes: fixed-wing,rotary-wing and flapping-wing.The flapping-wing flight mode has the characteristics of generating lift and thrust at the same time,the human-powered bird-inspired aircraft was designed in this thesis,which uses a hybrid wing combined with a flapping wing and a fixed wing,the mechanism that can realize synchronous flapping of left and right flapping wings and independent twisting were proposed,the structural design of the whole machine was completed.According to the problems existing in the human-powered bird-inspired aircraft,the design requirements of the aircraft were proposed,the aircraft is divided into four parts: hybrid wing,transmission mechanism,flapping wing mechanism and fuselage.The hybrid wing structure plan,the hybrid wing folding scheme,the flapping wing mechanism plan that can realize the synchronous flapping and independent twisting of the left and right flapping wings and the transmission mechanism plan that can realize the synchronous flapping of the flapping wing mechanism were determined.The composition and working principle of each mechanism were discussed.The size parameters of the hybrid wing were determined according to the flight biological scale rate and the size of the existing glider,the kinematics modeling of the transmission mechanism and the flapping wing mechanism was completed,the motion relationship among the input part,transmission part and output part was obtained,the mechanism parameters were determined through the motion design of the flapping wing target,the kinematics simulation analysis of the transmission mechanism and the flapping wing mechanism was completed based on ADAMS to verify the correctness of the simplified kinematics model and the rationality of mechanism parameter.The lift composition of the aircraft was analyzed,the aerodynamic calculation model of the hybrid wing was established through the blade element theory,the velocity expression of each point on the flapping wing at each time and the projected area expression of the flapping wing at each time was deduced,the calculation formulas of the lift and forward force of the fixed wing and flapping wing of the aircraft in the vertical descent attitude were derived.The calculation formulas of the forward force and steering torque after the active torsion of the flapping wing in the steering process were derived,and the theoretical calculation model of the aerodynamic force of the whole machine was obtained.According to the aerodynamic calculation formula,the aerodynamic influence parameters were analyzed,the lift generated by the flapping of the hybrid wing at different frequencies during uniform descent and slow landing was calculated,which lays a theoretical foundation for the verification of aerodynamic model.The simplified aerodynamic model was determined in the CFD,the boundary conditions were determined,the flapping lift of the aircraft in two cases was simulated and calculated.The simulation value was compared with the theoretical value to verify the reliability of the aerodynamic theoretical calculation model. |
