Research On Mechanism Design Of Bionic Flapping Wing Mcrio Air Vehicle Under Uncertainties

A flapping-wing micro air vehicle(FWMAV)is a bionic robot that can achieve stable flapping-wings flying by imitating the flight mechanism of the flying creatures in nature.Compared with the popular known fixed-wing and rotor flying modes,the bionic flapping-wing-flying mode shows considerable advantages,such as size advantages,flexibility,concealment,and bionic,which makes FWMAV own unprecedented broad application prospects in the fields of civil exploration,earthquake relief,military reconnaissance,and military offensive.Therefore,the bionic FWMAV has become a hotspot for future research and development of unmanned aerial vehicles.The design of the flapping-wing mechanism is the most important basement for FWMAV,converting the traditional rotary motion driven by electric energy into bionic flapping-wing flying motion.Therefore,the safety and reliability of the flapping-wing mechanism's operation have become a significant factor in determining whether the FWMAV can complete the specified goals,and the transmission efficiency of the mechanism will determine the efficiency of the FWMAV Since the inevitable uncertainties exiting during the design,manufacturing,assembly,and operation of the flapping-wing mechanism,the actual output motion is affected by the above uncertainties.It may lead to the failure of the flapping-wing mechanism,and ultimately the mission of the FWMAV To ensure safety and reliability during the operation,this work conducts the dynamic analysis for the flapping-wing mechanism under uncertainties.Based on this,the optimization design for the flapping-wing mechanism to improve the efficiency of energy utilization for FWMAV is introduced,while safety and reliability are guaranteed.The main content and innovations are summarized as follows.(1)The safety analysis and design model of the bionic flapping-wing mechanism are proposed.This dissertation proposes a design for a flapping-wing mechanism based on analyzing the flapping-wing motion of hummingbirds.After the analysis,the design requirements for the flapping-wing mechanism are firstly summarized,the motion model and the motion error model of the flapping-wing mechanism are then established.Finally,the safety analysis and design model of the flapping-wing mechanism is proposed.(2)Two time-dependent reliability approaches for flapping-wing mechanisms considering correlation are proposed.This work proposes a time-dependent reliability analysis model.Two time-dependent reliability analysis approaches are carried out to estimate the reliability of the flapping-wing mechanism.The first approach is to solve the reliability analysis of the mechanism under the random uncertainty of different distribution types,by transforming the time-dependent problem to a time-independent one and analyzing the correlation between multi-dimensional random variables.The second approach is supposed to calculate the time-dependent reliability of the mechanism under the random uncertainty with large variance.The time-dependent reliability is obtained based on the multi-dimensional extreme value distribution in time-space and random variable space.With the above two analysis approaches,the time-dependent reliability of the flapping-wing mechanism is analyzed,which provides a theoretical basis for the safety and reliability design of the flapping-wing mechanism.(3)A time-varying reliability analysis method of the flapping-wing mechanism considering joint clearance uncertainty is proposed.This work proposes a time-dependent reliability approach for the flapping-wing mechanism considering joint clearance of the mechanism.The reliability of the flapping-wing mechanism is estimated with high accuracy and efficiency.Based on the above research,a time-dependent reliability approach based on mechanism performance degradation is proposed.The cumulative process of joint clearance wear is considered in the full-cycle life process of the flapping-wing mechanism.Then the time-dependent reliability of the flapping-wing mechanism is estimated,which provides a theoretical basis for the optimal design of the flapping-wing mechanism throughout its life cycle.(4)The optimization model of the transmission efficiency for the flapping-wing mechanism with time-dependent reliability constraint is proposed.This work proposes a reliability-based design optimization model aiming to improve the dynamic transmission efficiency during the operation.By employing the deterministic constraints of the flapping-wing mechanism and the probabilistic constraints of the time-dependent reliability for the flapping-wing mechanism,the design of the mechanism is optimized with the dynamic transmission efficiency improved,while the requirement of mechanism time-dependent reliability is satisfied.Finally,the optimal design of the flapping-wing mechanism aiming to maximize the dynamic transmission efficiency is obtained by the proposed approach,realizing the improvement of the energy utilization rate and the extension of the endurance of the flapping-wing aircraft.