bluuebunny/crossref_metadata_2025_split huggingface dataset:
Transition state performance optimization of propfan engine based on DDPG algorithm
Authors: Zheng Hua , Yang Zhao-xing , Wang Ya-fan , Zhao Dong-zhu 
Published: May 2023

Abstract
As the “heart” of an aircraft, aero-engines work in harsh environments of high temperature and high pressure for a long time. In order to ensure that the engine can operate safely and reliably within the entire flight envelope, a large safety margin needs to be reserved in the design of the control system. This design idea limits the full play of the engine performance, so it is necessary to carry out the research on the performance search control (PSC) of aero-engine. This paper studies the performance optimization control of propfan engine based on deep reinforcement learning algorithm. The Deep Deterministic Policy Gradient (DDPG) algorithm, which is more suitable for continuous action space, is used to optimize the acceleration process of the propfan engine. The simulation results show that, compared with the unoptimized adjustment process, the transition state adjustment time of the engine is reduced by 32.5% under the action of the optimal adjustment law obtained by the DDPG algorithm. Therefore, the DDPG algorithm can be applied to the performance optimization of the engine acceleration process, and has a good transition state performance optimization effect.
Study on conjugate heat transfer characteristics of flexible structure of solid motor nozzle based on multiple working conditions
Authors: Wang Shengxiong , Li Yingkun , Xu Jinsheng 
Published: May 2023

Abstract
In order to study the influence of the deformations of the nozzle’s flexible sections on its inner wall’s heat transfer, this research uses the two-dimensional axisymmetric model and the k − ω SST turbulence model to numerically analyze the tail flow field of the flexible-extendible nozzle under multiple working conditions. The flow field and the inner wall’s heat transfer of the flexible sections with and without deformations are simulated and analyzed. The simulation results show that when the flexible sections are deformed, new shock waves will be generated in the tail flow field of the nozzle; the temperature and the heat flux of the first half of each flexible section decrease, while those at the end of each flexible section increase, and the deformations’ effect on temperature and heat flux diminishes over time. The research shows that the deformations of the flexible sections will make the inner wall’s heat transfer of the flexible sections uneven, and the inner wall’s ablation at the end of each flexible section may be aggravated, while that of the front half may be alleviated.
Effect of leading-edge parameters of multi-element airfoil on aerodynamic characteristic
Authors: Cai Jinyang , Luo Jiaming 
Published: May 2023

Abstract
Studying the effect of leading-edge parameters of 30P30N on aerodynamic characteristic was carried out. Effect of changing the gap and overlap of the slat of the airfoil were mainly investigated. Numerical simulation was applied to obtain aerodynamic characteristics, results show that: the lift coefficient in the linear segment basically does not change with the gap, the drag coefficient decreases with change of the gap. The overlap and gap of slat have obvious effect on the lift-to-drag ratio. The smaller the gap between slat and fixed wing, the greater the lift-to-drag ratio is achieved. With the increase of overlap between slat and fixed wing, lift to drag ratio increases.
A universal and simple method to solve the velocity / acceleration of parallel mechanism
Authors: Wang Rui , Guo Xiangyu , Zhong Shisheng , Ge Yuhao , Zhang Faqian 
Published: May 2023

Abstract
The velocity/ acceleration analysis is an important part of the kinematic analysis, which is of great significance to establish a universal and simple velocity / acceleration analysis model to realize the precise control of parallel mechanism. In this paper, according to the differential relationship among position, velocity and acceleration, the velocity / acceleration mapping formula between the driving branch and the position and attitude parameters of the moving platform is established. Moreover, in order to ensure the accuracy of calculation, the characteristic value correction iteration method is used to solve the singular and ill-conditioned of Jacobian matrix and Hessian matrix which may be generate under some special attitudes. The principle of the method is universal and easy to understand, moreover, the experiments show that the method can realize the velocity / acceleration solution of hybrid drive mechanism.
Numerical simulation of the effect of different impeller structural parameters on the lift and thrust of a new impeller thruster
Authors: Chen H , Wang S , Wang Z X , Wang X Y , Qiu Z Z 
Published: May 2023

Abstract
The Half-Rotating impeller thruster(HRIT) based on the Half-Rotating Mechanism is a new type of impeller thruster. Its impeller motion principle is different from the fixed impeller of the ordinary impeller thruster. In order to obtain better aerodynamic force in working, it is necessary to explore the HRIT in different structural parameters. The influence of the radius of the rotating arm, the width of the blade is calculated and analyzed in detail by numerical calculation method. The calculation results show that the radius of the rotating arm is the main factor affecting the lift and thrust of the HRIT. The aerodynamic characteristics of the thruster under different blade widths are also different. The aerodynamic characteristics of the thruster under different blade widths are also different, the lift reaches its peak value when blade widths d=30mm, and the thrust reaches its peak value when d=35mm; The blade lengths also has a great influence on the aerodynamic force of the thruster, and the lift and thrust both increase with the increase of blade lengths. At the same time, compared with the fixed impeller thruster, the HRIT has relatively balanced aerodynamic performance.
Dynamics Research and Analysis of landing on the surface of Asteroid
Authors: Chen Danhe , Li Chuangyi , Su Zhou 
Published: May 2023

Abstract
Asteroid detection has been the main research field of deep space exploration, and even in the future years. Countries have carried out missions to flyby and landing on the surface of asteroids, the sampling can help human explore the origins of small bodies, as well as origin of the solar system. While the particular environmental factors such as small size and low gravity of asteroids make the landing more difficult, this paper designs a four-legged inverted triangle soft lander, supplemented by thrust reversers and rope anchors for stable landing. A mathematical model of the lander landing on the surface of target asteroid is established, and the motion and dynamic response of lander in different landing modes is studied, conditions and safe landing range is well defined. Results of the analysis have demonstrated the effectiveness of dynamic landing model for the proposed lander.
Finite element dynamic modeling and attitude control for a slender flexible spacecraft
Authors: Huang Wenke , Li Linfeng , Dong Wenye , He Liwen , Feng Taoming , Xiao Jun 
Published: May 2023

Abstract
This paper aims to study the dynamic modeling and attitude control of a kind of slender flexible spacecraft. The basic structure of this kind of spacecraft is different from the traditional structure of a center rigid body with flexible appendages, but rigid bodies at both ends, which are connected by a flexible truss structure. Firstly, the finite element modeling method is adopted to establish the dynamic model of this kind of spacecraft, and the vibration frequency and damping of the flexible structure are obtained. The unconstrained modes of the flexible spacecraft are obtained through mathematical analysis, finite element analysis and frequency domain analysis. In addition, a nonlinear sliding surface with angular velocity constraint is designed. On this basis, an adaptive sliding mode (ASM) controller is proposed, stability of the close-loop system under the controller is proved, and the dynamic model is verified through mathematical simulation.
Optimal trajectory planning technology for the cooperative flight of unmanned aerial vehicles
Authors: Feng Kai , Nan Ying 
Published: May 2023

Abstract
In the face of a complex battlefield environment, a multi-dimensional dynamic planning algorithm is proposed to solve the trajectory planning problem of the cooperative flight mission process of unmanned aerial vehicles. Under the constraints of aircraft kinematics, the collision between aircraft and space-time cooperation, and under the influence of random wind field, threat area, and other interference factors, the algorithm can make the UAV group pass through the mission points as much as possible, and at the same time, smooth the track points to make the trajectory reach the optimal solution. Finally, the simulation results of the program written in C++ and MATLAB show that the algorithm can meet the global optimization, and can calculate in real-time and online. It has strong engineering application value.
Research on modelling analysis and design method of helicopter operation requirements based on MBSE
Authors: Sun L , Gao F , L L Q , Lou B C 
Published: May 2023

Abstract
Helicopters are characterized by complex missions, high risk, high cost, high reliability and long lead times. In order to adapt to the more complex operational requirements in the future, the thesis addresses the problems of long iterative cycles, low efficiency and model duality in the traditional helicopter operation requirements analysis process, the theory of model-based systems engineering (MBSE) is introduced into operation requirements analysis for helicopter. A modelling analysis and design method for helicopter operation requirements analysis is proposed based on MBSE. The overall framework for helicopter operation requirements analysis based on the model is designed. On this basis, a modelling design method and key implementation process of requirements analysis is established, which provides theoretical and technical support for the positive design of helicopter operation requirements demonstration.
Attitude control of a moving mass-actuated fixed-wing UAV based on LADRC
Authors: Zheng Jingzhong , Selezneva Maria Sergeevna , Yi Jianfeng , Zhu Liangliang 
Published: May 2023

Abstract
This paper concerns attitude control of a moving mass-actuated fixed-wing unmanned aerial vehicle (MFUAV). Unlike conventional roll motion of UAV, which is controlled by ailerons, this MFUAV uses the movement of mass block inside the wing to generate roll moment. It is difficult to design a suitable attitude controller for it due to the strong non-linearity and coupling of the MFUAV dynamics. Linear active disturbance rejection control (LADRC) proved to be a simple and effective alternative to conventional PID control. LADRC is able to eliminate disturbances with the help of extended state observer (ESO) and does not depend on the accurate mathematical models of particular systems. Finally, simulation results show that the attitude tracking control of MFUAV is well achieved with robustness. This shows that the designed method is easy to adapt and implement during the actual flight of the MFUAV.
Optimized relative phase maintenance for heterogeneous area-to-mass ratio microsatellite constellations
Authors: Liu Siyang , Meng Tao , Jin Zhonghe 
Published: May 2023

Abstract
Long-term maintenance missions present a challenge for low-orbit heterogeneous area-to-mass ratio (AMR) microsatellite constellations due to inconsistent fuel consumption and carrying capacity. Based on the idea of cooperative control, the fuel consumption of fuel-rich satellites is properly increased in this paper to assist fuel-starved satellites in saving fuel, so as to optimize the fuel consumption balance of each satellite and extend the controllable lifetime of the constellation. The evolution of the relative phase under J2
and atmospheric drag perturbation is analyzed. The target configuration and the strategy of maintenance are modeled and optimized based on the principle of fuel consumption balance. The traditional absolute phase maintenance method for heterogeneous AMR constellation is devised. On this basis, the orbit altitude is optimized with the simulated annealing algorithm to improve the fuel consumption balance. Based on the relative phase maintenance method, the maintenance strategy is optimized with the genetic algorithm to further reduce fuel and enhance the fuel consumption balance. Finally, the three methods are contrasted.
Integrated flutter test of a horizontal-tail model in the large-scale continuous transonic wind tunnel
Authors: Han Jiangxu , Liu Nan , Huang Yanxin , Yang Ximing , Wang Song 
Published: May 2023

Abstract
Wind tunnel test is a critical way to investigate flutter characteristics of aircraft, particularly in identifying the transonic dip phenomenon in the aeroelastic design. The continuous wind tunnel has advantages over the blow-down wind tunnel in long running time, wide bandwidth of dynamic pressure, and stable flow field. Thus, the continuous wind tunnel is more suitable for transonic flutter tests. Flutter test techniques are studied for FL-62 wind tunnel, the first large-scale continuous transonic wind tunnel in China. A protection system and a real-time signal processing are developed to ensure the safety and efficiency. Flutter boundaries of a horizontal-tail model are investigated in FL-62 wind tunnel in the Mach number regime between 0.65 and 0.98. In the test, structural vibrations are measured via strain gauges, deformations and pressure distributions are measured via non-contact optical techniques, and flutter boundaries are predicted via a modal identification method.
Experiment research on instantaneous characteristics of variable-thrust hybrid rocket motor by reconstruction techniques
Authors: Wei Tianfang , Cai Guobiao , Tan Guang 
Published: May 2023

Abstract
The firing test of variable-thrust Hybrid Rocket Motor (HRM), operated with Hydrogen Peroxide (HP) and Polyethylene (PE), based on closed-loop thrust control, has been carried out in this paper. The experiment research on instantaneous characteristics of HRM is conducted based on reconstruction techniques. A post-processing software has been developed to reconstruct the instantaneous performance parameters during the burning stage of HRM. Meanwhile, the formula of regression rate is fitted by reconstruction results through a single firing test, which is a significant advantage compared with traditional method. The averages of instantaneous parameters calculated by reconstruction techniques accord well with experimental data summarized by traditional consumption weight loss method, and the accuracy of reconstruction calculation is better than 1%. This paper is designed to achieve the reconstruction for instantaneous parameters and research the instantaneous characteristics during the variable-thrust firing test of HRM. The reconstruction techniques have the better accuracy, and also provide a critical method for the research on instantaneous characteristics of hybrid rocket motor.
Parameter sensitivity analysis under failure condition of lifting device mechanism
Authors: Feng Yunwen , He Zhiyu , Li Shuai , Xue Xiaofeng , Cao Mingyue 
Published: May 2023

Abstract
The sensitivity of each influencing parameter in the selected range of the complex multi-hinge space flap mechanism under typical fault conditions is studied, and the influence degree of each parameter and its dispersion on the driving torque of the mechanism is determined. Firstly, the rigid-flexible coupling dynamic model of the mechanism is established considering the flap deformation, and then the influence of four parameters that may cause mechanism failures, such as hinge friction, aerodynamic load, driving speed and assembly error, on the driving torque of the mechanism is explored. Then, the drive torque of the mechanism under each parameter value is given, finally, the sensitivity of each selected parameter is obtained by the direct de rivation method. The results show that the parameters are positively correlated with the driving torque, the aerodynamic load coefficient and hinge friction parameters are the most sensitive to the driving performance of the mechanism, while the driving speed is the smallest. After the aerodynamic load increased by 30%, the maximum driving torque of the inner mechanism increased by 28.8%; when the hinge friction parameter was in the range of 0~0.05, the maximum torque of the inner and outer mechanisms increased by 8.6% and 8.4% respectively. In engineering applications, the lubrication of each spherical hinge should be increased, the driving speed should be reduced, and the manufacturing and assembly accuracy should be improved.To a certain extent, it can prevent failures and improve the reliability of the flap mechanism.
Review on vibration test and fault analysis of rv reducer
Authors: Xuan Liang , Hong WenXiong , Wan ZeFu , Lin Zhuang 
Published: May 2023

Abstract
As the core component of industrial robot RV reducer, its health condition determines the life and accuracy of the robot. The main reason that restricts the long-term stable operation of industrial robots. This paper analyzes and compares the advantages and disadvantages of various technologies from three aspects: state detection, signal processing and fault diagnosis. The problems of developing real-time online evaluation are also discussed. Deep data mining and exploring new methods of RV reducer condition monitoring are the research difficulties in this field. It provides a reference for further research in the field of RV reducer.
Influence of panel oscillation on the shock flow field in isolator under complex background wave system
Authors: Wang Tiexiang , Li Yingkun , Zhu Min , Zhou Changsheng 
Published: May 2023

Abstract
In this paper, a self-developed solver is used to numerically simulate the isolator section under complex inlet conditions, and the influence of forced panel vibration on the shock flow field in the isolator under complex inlet conditions is investigated. The results show that the forced vibration of the panel has a certain influence on the shock flow field in the isolator under complex inlet conditions.
Pattern mining based data fusion for wind turbine condition monitoring
Authors: Chesterman Xavier , Verstraeten Timothy , Daems Pieter-Jan , Nowé Ann , Helsen Jan 
Published: May 2023

Abstract
The profitability of wind turbine energy production is for an important part determined by the operation and maintenance costs of wind turbines. An important driver of these costs is currently the premature failure of components due to excessive wear. If it would be possible to accurately predict these failures, preventive maintenance can be made more effective, which should result in less downtime and expensive unexpected failures. This in turn should lower the operational and maintenance costs. The research presented here is a contribution to the research on condition monitoring and failure prediction for wind turbines. To this end, a methodology for failure prediction is designed that combines (fuses) multiple information sources (i.e. SCADA and status log data). The novelty of this research lies in the fact that pattern mining techniques are used to identify relevant rules for a rule-based failure classifier. The methodology is validated on generator bearing failure cases from a real operational wind farm. The results show that the methodology is able to predict generator bearing failures accurately well in advance. The rules on which the predictions are based are interpretable and correspond in general to expert knowledge on the matter.
Social acceptance “in my backyard” - What drives social acceptance of renewable energy projects?
Authors: San Martin O 
Published: May 2023

Abstract
This paper aims to present a general overview of the social acceptance of wind energy developments in Europe and identify influential social acceptance factors. First, we show social acceptance levels for renewable energy (onshore wind) projects in selected European countries and how it varies across and within countries. In addition, we produce regional maps showing within country variations in social acceptance indicators. Second, using an econometric model, we study how different factors influence social acceptance levels. Our investigation assesses social acceptance of renewable energy developments using primary data from two comprehensive opinion surveys. The first opinion survey-conducted in September/October 2021-contains more than 16 000 observations from 8 European countries and allows us to assess how social acceptance is affected by the distance to the wind parks. The second opinion survey – conducted in June 2022 - contains more than 18 000 observations from 9 European countries and allows us to assess-through an econometric model how social acceptance is affected by a set of relevant influential factors, including perceptions, preferences towards energy suppliers, preferences for community benefits schemes, and demographic factors among others. The analysis of the information gathered for this investigation shows variations across European countries and within each of the countries covered by this study. The findings from this study might be helpful to take into consideration during the planning and development of renewable energy projects and improve targeting the work towards community engagement aiming to obtain the social license to build and operate renewable energy projects.