Design and experiment of the"Feng Ru 3"highly efficient ultra-long endurance unmanned aerial vehicle
[Objective]Ultra-long endurance unmanned aerial vehicles are advanced aircraft with excellent sustained flight capability and have the characteristics of low-cost,long-term,large-scale,and high-density intelligence collection and monitoring tasks.Due to these advantages,the ultra-long endurance unmanned aerial vehicle has become an important direction for future air vehicles.[Methods]Undergraduates from Beihang University have proposed a scheme for a highly efficient ultra-long endurance unmanned aerial vehicle,"Feng Ru 3."This scheme contains the ultra-high-aspect-ratio wing,low-drag drop-shaped fuselage,and high-placed empennage.These compose a highly efficient aerodynamic configuration.In addition,the flying platform structure is constructed from a novel composite material with light weight and high strength.This project has innovatively designed a dual-loop power system consisting of an inner loop electronic fuel injection system and an outer loop engine health monitoring system.The team has developed a durable loitering flight control system involving gust alleviation technology and PID parameter self-adaptation technology based on open-source flight control equipment.In addition,this project abandons the traditional takeoff and landing method of the landing gear and shows an innovative vehicle-based takeoff method.[Results]Ground testing(including wind tunnel test,structure static test,propulsion system test)and flight test(including autonomous takeoff and landing test,dolly takeoff test,and long-endurance flight test)are performed on"Feng Ru 3".The experimental results reveal that(1)the highly efficient aerodynamic configuration vastly increases the aerodynamic efficiency,resulting in a maximum lift-to-drag ratio of～18.36.(2)The wing and tail made by ultra-light and high-strength composites can withstand a load of 4G,and their flexural changes are within an acceptable range.The stiffness of the tail support carbon tube also meets the design requirements.(3)After multiple 120-h experiments,it is proved that the dual-loop power system can drive the propulsion system super efficiently,enduringly,reliably,and cost-effectively.(4)The introduction of the adaptive PID algorithm in the flight control system of this project can effectively support stable,energy-efficient,and reliable completion of long-endurance flight missions.(5)The project adopts a takeoff method using a vehicle.This approach can reduce about 5 kg of the weight of the landing gear and its additional structures present a higher aerodynamic efficiency,reducing approximately 10%of aerodynamic drag.[Conclusions]Due to the highly efficient aerodynamic configuration,ultra-light and high-strength composites,a highly reliable dual-loop power system,a durable loitering flight control system,and the vehicle-based takeoff method,this developed unmanned aerial vehicle has achieved a comprehensive breakthrough in the capability of executing ultra-long endurance missions.Despite extreme and adverse weather conditions,including wind gusts of 7-8 levels,"Feng Ru 3"successfully achieved an uninterrupted flight of 80 h,46 min,and 35 s.This achievement of"Feng Ru 3"has set the world record for"the endurance of 25-100 kg class oil-powered fixed-wing unmanned aerial vehicle"certified by the International Aviation Federation.
NETL
NSTL
万方数据
