Generating Mechanism And Estimation Method Of Lift Force For Half-rotating Wing

Half-Rotating Wing(HRW) flight mechanism based on simplified Half-Rotating Mechanism(HRM) is a new kind of flapping wing system with rotating flapping instead of oscillating flapping. The continuous rotation makes HRW overcome large inertia force skillfully generated in reciprocating swing of flapping wing aircraft, which is likely to be a breakthrough in the large size and high lift and make bionic aircraft in large size possible. This simplified HRW aircraft will be a major research direction to change the traditional aircraft. It is a very forward-looking new type of aircraft. The study around HRW lift was carried out by combining with relevant research results of HRW flight mechanism. The research results not only provide support for aircraft lift estimation and wing parameters design, but also furnish theoretical guidance to the aircraft flight control.Upon analysis and summary for the related studies about bionic flapping-wing flight lift formation mechanism at home and abroad, the flight lift was divided into Lift of Flow Around Wing(LFAW) and Lift of Flow Dragging Wing(LFDW) in this paper by observing the characteristics of bird flight and according to the basic aerodynamic characteristics of an object flowed around by air. The internal mechanism of bird flight in different patterns was explained after summarizing the change rule of the two component forces. The theoretical estimation formulas of LFAW and LFDW were deduced after simplifying the model of bird flapping wing, which established theory basic for further analyzing generating mechanism and estimation of HRW lift.Based on the lift mechanism of LFAW and LFDW, the lift of HRW was analyzed deeply. HRW driving mechanism and its basic movement were introduced, and the existence of chordwise airflow and spanwise airflow on the wing was explained when HRW was moving. Two airflow lift estimation models of HRW were established respectively. The theoretical estimation formulas of LFAW and LFDW from the two airflow lifts were given, and the key parameters which affected the lift force were analyzed. The research could guide the improvement about lift force of HRW, as well as provide theoretical basis for the lift estimation of HRW at different flight states.The lift values of blade at different positions were estimated by Mathcad when HRW prototype was in hovering flied forward with different flight parameters. The average LFAW and LFDW and the relationships between LFAW and LFDW of HRW and crank angle respectively were given under the corresponding condition of flying forward. Lift estimation for HRW prototype at different flight parameters was helpful to improve wing parameters of prototype and subsequent design of HRW aircraft, and made preparations for verifying the lift estimation method of HRW.The model of HRW was established in the fluid simulation software XFlow and the relevant parameters were set. Numerical calculation was carried out for the lift of HRW under the condition of hovering and flying forward. Simulation lift of HRW was output under the same parameters and positions conditions as theoretical estimation. The estimation lift and the simulation lift were compared by Matlab to verify the effectiveness of the method for estimating the lift of HRW, and the reasons of the difference between the theoretical and the simulation results were analyzed.