Abstract:The civil aviation community is actively exploring and developing the solutions of single pilot operations (SPO) for large commercial aircraft. Human factors engineering research for SPO has been launched, and the research mainly focuses on three research solutions： flight deck airborne equipment upgrade, flight support from ground stations, and the combined SPO solution of “flight deck airborne equipment upgrade + flight support from ground stations". This paper reviews and analyzes the progress of human factors engineering research on SPO. The preliminary research outcome tends to support the combined SPO solution. However, the current human factors engineering research is not comprehensive and cannot provide a complete human factors engineering solution for SPO. For future human factors engineering research, this paper analyzes the key human factors issues on SPO and points out the gaps in the current research and the key areas for future work. Finally, this paper puts forward an overall strategy and recommendations for future human factors engineering research on SPO.

Abstract:Hypersonic vehicle is subjected to severe aerodynamic load and aerodynamic heating during the flight. Thus structural dynamic stability and response caused by aerodynamic force and aerodynamic heating should be fully considered in the design process of structure, and thermal flutter is one of the key parts. This paper reviews the development of thermal flutter research, summarizes various existing methods for thermal flutter research, including thermal modal test, thermal flutter simulated analysis and wind tunnel test. On this basis, the research status and existing problems of ground flutter test, which can be used in the study of thermal flutter, are summarized, and the future development of ground thermal flutter test is prospected.

Abstract:The aerodynamic characteristics of the vertical tail of an aircraft are directly related to the size and weight of the vertical tail. Increasing the lift force of the vertical tail using flow control can further reduce the size of the vertical tail, which has practical significance for reducing the weight of the structure. In this paper, the CFD method is used to numerically simulate the active flow control of vertical tail using the co-flow jet technique. The influence law of jet momentum coefficient on continuous co-flow jet and the influence law of jet momentum coefficient, blockage ratio, injection hole number on discrete co-flow jet is studied. The results show that for the continuous co-flow jet, with the increase of jet momentum coefficient, the effectiveness of lift enhancement, drag reduction and separation suppression becomes more significant. When the jet momentum coefficient reaches 0.14, the lift coefficient is nearly twice that of the baseline vertical tail, which means that the vertical tail size can be reduced by about 50%. For the discrete co-flow jet, compared with the continuous co-flow jet, the effectiveness of lift enhancement gradually decreases with the increase of the blockage ratio, and the power consumption also decreases at the same time. An appropriate blockage ratio can produce better comprehensive control effect. For the model and flow condition in the present study, with the increase of the discrete hole number, the lift enhancement effect first increases and then decreases. When the injection hole number is 5, the lift coefficient reaches the maximum. When the number of nozzle is 20, the comprehensive aerodynamic efficiency considering energy consumption is better.

Abstract:An accurate description of the transition corridor is important for VTOL fixed-wing UAV flight. To study the transitional flight process of vertical take-off and landing fixed-wing UAVs, a transition corridor model of this type of UAV is established in this article. From the perspective of flight dynamics, the deflection angle-speed envelope of the power system is studied with the maximum lift coefficient of the wing and the system available power limit. The influence of the overall parameters and energy parameters of the UAV on the deflection angle-speed envelope of the power system is analyzed, and a method to expand the transition corridor of the vertical take-off and landing fixed-wing UAV is proposed. Through case calculations, the transition flight corridors were obtained, and based on the transition corridor model calculations, it was concluded that increasing the available power by 10% can expand the transition corridor by 21.43%, while increasing the aerodynamic parameters by 10% can only expand the transition corridor by 2.33 %.

Abstract:When flying in formation, the downstream individual maintains a proper state of motion in the wake produced by the upstream individual, which has an important impact on reducing drag and saving energy. In this paper, the influence of flexibility on the motion of a semi free filament in a vortex street is investigated by using the immersed boundary method. The numerical simulation results show that when the filament flexibility changes, the change of filament motion state is related to the flow field conditions. When｜VГy｜/｜Vp｜is less than 0.175, the motion state of the filament remains unchanged by changing the flexibility of the filament, and the filament moves around the vortex cores in the vortex street. When 0.175<｜VГy｜/｜Vp｜< 0.3, the filaments swing adaptively on the side of the vortex street. By reducing the flexibility of the filament, the motion state of the filament will change from moving on the side of the vortex street to moving around the cores. When 0.3≦｜VГy｜/｜Vp｜, the motion state of the filament remains unchanged by changing the flexibility of the filament, and the filament swings adaptively on the side of the vortex street. Compared with the motion around the cores, when the filament moves on one side of the vortex street, the drag decreases obviously. The numerical simulation results in this paper provide valuable reference for the flexible design of aircraft in formation flight.

Abstract:Autonomous path planning of UAV is a key technical problem for future UAV operation. In view of the shortcomings of traditional route planning methods, such as low efficiency, poor real-time performance, easy to fall into local optimum, this paper proposes an improved heuristic ant colony algorithm for UAV route planning. In the early stage of the algorithm, Dijkstra algorithm is used to initialize the track, and heuristic information is introduced to improve the search efficiency; Logistic chaotic map is used to initialize pheromone to increase the diversity of solutions and improve the convergence speed of the algorithm; in the middle and late stage of the algorithm, multi track selection strategy and simulated annealing mechanism are used to improve the global search ability of the algorithm and avoid falling into local optimum due to too fast convergence speed Solution. The simulation results show that in the complex environment with threats and obstacles, compared with the basic ant colony algorithm, the improved ant colony algorithm can effectively plan a path from the start to the end, and has higher optimization accuracy and faster convergence speed, which has a certain application value.

Abstract:Airdrop systems are widely used in aerospace fields such as a landing and recovery equipment. The LS-SDYNA was used to simulate the landing process, and to compare the performance of the airdrop system under the rigid and soil ground. Meanwhile, the effect of different lateral wind velocities on the airdrop impact performance was analyzed. The results show that the difference of the maximum overload of the cargo is very small between the case of the rigid and the soil ground when the airdrop system only strikes the ground perpendicularly; the difference is much greater and the deformation effect of soil ground is significant under lateral wind conditions.

Abstract:In order to realize the dynamic prediction of the taxi time in busy airports and improve the prediction accuracy, an aircraft dynamic taxi time prediction method based on XGBoost is proposed for the first time. Firstly, the key characteristic index of variable taxi time prediction is constructed by analyzing various factors affecting the taxi time. Then, XGBoost algorithm is selected to establish the variable taxi time prediction model, and the key input parameters of the model were adjusted and tested. Finally, the prediction effect of XGBoost algorithm is compared with random forest and support vector regression. At the same time, the correlation between sample data size and prediction accuracy of taxi time is analyzed for the first time. Taking Guangzhou Baiyun International Airport as the analysis object, the results show that the prediction accuracy of the taxi-in and the taxi-out time reaches 94.1% and 96.6% by using the XGBoost algorithm, which are better than the mainstream algorithms of random forest and support vector regression. In addition, more than 32,000 samples are needed for accurate and stable prediction of dynamic taxi time at Guangzhou Airport.

Abstract:In order to overcome the shortcomings of traditional evaluation methods in determining the index weight and fuzzy evaluation method in determining the degree of membership, Establish an evaluation index system based on the characteristics of general airport apron operations, Using variable weight and relative difference function methods to assess the safety risks of general airport apron operations. Firstly, the constant weight of each evaluation index is adjusted by using the variable weight theory, and then the membership degree of each safety level is determined by using the relative difference function, so as to eliminate the limitation of experts" experience and knowledge. The airport apron operation risk level calculation result is correct. Theoretical analysis and case calculation show that the method can reflect the impact of risk sources on risk assessment value more objectively.

Abstract:The drooping front is a simple lifting device, which can effectively reduce the aerodynamic noise and the motion space of the mechanism. It has been applied to A380 and A350XW. In order to realize the fixed-axis rotation of the drooping front according to the given requirements, a design method of hinged drooping front mechanism based on four-link is proposed. In this paper, according to the card position requirements of takeoff and landing, based on the position relationship of the reference point on the leading edge, the motion axis is obtained by mathematical analysis. Combined with the size and motion angle requirements of the driving mechanism of the droop leading edge, the frame model of the droop leading edge mechanism is calculated. On this basis, according to the kinematics simulation of the mechanism, the changes of the transmission angle and the rocker arm angle with the motion angle of the driving arm during the movement of the mechanism are clarified. Further, through the rigid-flexible coupling dynamics simulation of the drooping front mechanism, the driving torque and the hinge point load during the movement of the mechanism are obtained. The results show that with the uniform rotation of the driving arm, the hinged droop front can be steadily reduced by 26° ; The ratio of the maximum driving torque of the two driving planes is close to 3 : 2, indicating that the force transmission performance is good, the load distribution is reasonable, and the lateral load at the driving position is improved by the setting of the side strut. The proposed design method provides a new idea for the design of hinged droop leading edge mechanism, which has good reference significance in modern civil aircraft design.

Abstract:The existing research on flight test risk control techniques related to flutter/ASE test is not systematic, have limited consideration of civil fly-by-wire aircraft characteristic and onboard flight test engineer. The more systematic study was proposed including theoretical evaluation, instrumentation, flight test technique, risk analysis, mitigation measures and emergency procedures covering flight test preparation and test conduction. Three hazards were identified including flutter/ASE unstable, adverse handling qualities and local structure damage. A technique was proposed that onboard flight test engineer cutoff excitation when vibration exceed limit. A dedicated monitor software was developed to calculate damping ratio and ASE margin in telemetry. A civil aircraft flight flutter/ASE test shown that the proposed technique reduces flight test risk and cost effectively, manual cutoff excitation within 1 second protect aircraft structure, real-time analysis can provide stability margin timely and improve test efficiency.

Abstract:Helicopter flight test is an important means to verify whether the flight performance meets the requirements of airworthiness regulations under the environmental conditions close to the maximum altitude limit. During the performance flight test at high plateau, the helicopter is near the using limitation, the flight risk is high. It is necessary to study and develop reasonable and safe test flight methods to obtain accurate helicopter performance data while ensuring test flight safety. This paper studied the requirements of airworthiness regulations for high plateau test flight, determined the test flight method of each test flight items, and applied the test flight methods to complete the H425-100 helicopter high plateau test flight at Yushu Batang airport at 3950m above sea level. It shows that the testing methods determined in this paper is reasonable and feasible. Tethered hover method can improve the efficiency of test flight. Using OEI simulating mode can effectively reduce the risk of test flight. The fitting method can be used to determine the helicopter take-off and landing distance more accurately.

Abstract:Aileron is a device to simulate the support stiffness of aileron actuator. It is a key device in aviation ground load test. The research on the variation law of aileron stiffness simulator with position is beneficial to its design and application, and has important engineering value. In this paper, the mathematical model is established, the stiffness reduction factor is proposed, and the stiffness characteristics of the stiffness simulator are discussed; the stiffness simulation of the simulator is carried out, and the correctness of the mathematical model and simulation is verified through the stiffness test; the thickness of the simulator is optimized based on the sensitivity of the target stiffness to the distance. The results show that the stiffness reduction factor can quickly predict the stiffness characteristics of the simulator, and 7mm is the optimal thickness of this model stiffness plate.

Abstract:At present，there is a lack of comprehensive analysis and evaluation of commercial aircraft economic benefits for manufacturers at home and abroad. In this paper an index system for OEM is developed to evaluate commercial aircraft economic performance，which combined value analysis of technology economics and aircraft design engineering. Four layers index，including cost，product，business and market are established. Gray relational method is adopted to analyze a type of aircraft. Results show that this index system reflects the relation between commercial aircraft technology capability and market performance，which is in compliance with market regularity and will be useful in product planning，engineering evaluation，project demonstration and marketing strategy.

Abstract:With the increasingly busy operation of civil aviation airspace, the possibility of flight conflict on air route increases. From the perspective of quantitative analysis, how to build an effective and reasonable mathematical model for the quantitative assessment of flight collision risk on air route, improve the scientificity of air route planning and management, and build an effective and reasonable mathematical model for the quantitative assessment of flight collision risk on air route is a problem facing the industry. An improved Event model based vertical collision risk assessment method for flight route is proposed. In this method, the cuboid in the original Event model is replaced by two elliptical cones which correspond to the velocity vector distribution of the aircraft in space. The probability of the aircraft passing through the adjacent altitude layers is calculated, and the vertical collision risk value of the aircraft in the improved route is derived from the ratio of the area size of the collision box before and after the improvement. Calculation examples show that the vertical collision risk of the improved method is about 50% of that of the original cuboid Event model, and 60% of that of the original ellipsoid Event model. The improved collision risk model is more reasonable and feasible.

Abstract:The modeling optimization of hydraulic shell pipeline for 3D printing should not only meet the function and performance requirements，but also embody the advantages of 3D printing technology.Through the curve and surface algorithm based on NURBS,a set of modeling optimization method suitable for hydraulic shell pipeline is established. The key line is obtained by the method of edge line extraction, and the pipeline routing is designed based on the principle of reducing the flow resistance and energy loss as much as possible.In order to reflect the advantages of 3D printing technology as the goal,to achieve product function and performance as constraints,the hydraulic shell pipeline modeling optimization was carried out,and the fluid simulation analysis was carried out.The results show that：after optimization，the maximum local pressure of Z-shaped pipeline is reduced by 99.8%，the negative pressure area is significantly reduced，and the flow velocity is reduced.The optimized hydraulic shell surface pressure distribution is more uniform，the pressure loss is reduced by 53.2%,and the performance of the shell is significantly improved.

Abstract:In recent years, RFID technology has been widely used in the field of civil aviation airport transportation, but it is rarely used in the field of civil aviation manufacturing and aircraft operation and maintenance, and lots of work are still carried out by original manual observation. Efficiency and accuracy can be greatly improved by using RFID technology reasonably. This paper proposes a system architecture that uses RFID technology to be applied to the life cycle maintenance and management of civil aircraft airborne equipment. The function and configuration of its key components are explained, and a routine maintenance task for cabin emergency equipment is adopted to verify the system. This system can realize efficient maintenance and management of the entire life cycle of airborne equipment, and has a great application prospect

Abstract:In order to solve the problems of disconnection between quality control and business process, insufficient quality planning and high control costs in the military aircraft final assembly stage, APQP application guide（MAFA-APQP） suitable for the military aircraft final assembly stage was proposed by improving the APQP guidance material of the IAQG, including theoretical models, core content and key elements, etc. The application effect of the military aircraft assembly APQP in process optimization and management, risk identification and control were verified on the aero-engine installation. The results show that the military aircraft assembly APQP is beneficial to predict and reduce risks, reduce process changes, improve military aircraft quality and delivery efficiency.

Abstract:High quality project discovery is an important prerequisite and guarantee for technological innovation. Analyzing the influencing factors of major key technology project discovery in aviation field can effectively support its project discovery process. On the basis of summarizing the general process of knowledge aggregation and analyzing the characteristics of major key technology project discovery in aviation field，a model of major key technology project discovery in aviation field based on knowledge aggregation process is constructed. On this basis，through interview analysis and questionnaire survey，the influencing factors of major key technology projects in aviation field are explored，and classified by factor analysis in this paper. The results show that the discovery of major key technology projects in the aviation field is affected by a total of 10 factors in 3 categories，including personnel material support，project discovery technology and project discovery process management.

Abstract:This paper uses the aerospace engineering journals included in JCR as the data source, selects the papers published by Chinese scholars in the decade from 2011 to 2020, and uses the CiteSpace software to visually analyze the publication status of Chinese universities in the field of aerospace, author cooperation, research institution cooperation, keyword co-occurrence, and keywords clustering. The research results show that research in the field of aerospace has attracted more and more attention from scholars in Chinese universities; in particular, universities with special features in the defense industry conduct more research; there is more cooperation in the same region, but less cross-regional cooperation; The current research mainly focuses on the six categories of overall aircraft design, hypersonic aircraft, guidance and control, aircraft structure design, fluid mechanics, and engine design. This paper provides a valuable theoretical basis for my country"s universities, especially the national defense industry"s characteristic universities, to conduct in-depth research in the aerospace field.