Flight data of a twin-jet transport aircraft in revenue flight are analyzed for potential safety problems. Data from the quick access recorder （QAR） are first filtered through the kinematic compatibility analysis. T...Flight data of a twin-jet transport aircraft in revenue flight are analyzed for potential safety problems. Data from the quick access recorder （QAR） are first filtered through the kinematic compatibility analysis. The filtered data are then organized into longitudinal- and lateral-directional aerodynamic model data with dynamic ground effect. The dynamic ground effect requires the radio height and sink rate in the models. The model data are then refined into numerical models through a fuzzy logic algorithm without data smoothing in advance. These numerical models describe nonlinear and unsteady aerodynamics and are used in nonlinear flight dynamics simulation. For the jet transport under study, it is found that the effect of crosswind is significant enough to excite the Dutch roll motion. Through a linearized analysis in flight dynamics at every instant of time, the Dutch roll motion is found to be in nonlinear oscillation without clear damping of the amplitude. In the analysis, all stability derivatives vary with time and hence are nonlinear functions of state variables. Since the Dutch roll motion is not damped despite the fact that a full-time yaw damper is engaged, it is concluded that the design data for the yaw damper is not sufficiently realistic and the contribution of time derivative of sideslip angle to damping should be considered. As a result of nonlinear flight simulation, the vertical wind acting on the aircraft is estimated to be mostly updraft which varies along the flight path before touchdown. Varying updraft appears to make the descent rate more difficult to control to result in a higher g-load at touchdown.展开更多
This article studies the fault recorder in power system and introduces the Comtrade format. Andituses C++ programming to read recorded fault data and adopts Fourier analysis and symmetrical component method to filter ...This article studies the fault recorder in power system and introduces the Comtrade format. Andituses C++ programming to read recorded fault data and adopts Fourier analysis and symmetrical component method to filter and extract fundamental waves. Finally the effectiveness of the data processing method introduced in this paper is verified by CAAP software.展开更多
Increasing the resolution of seismic data has long been a major topic in seismic exploration.Due to the effect of high-frequency noises,traditional methods could only improve the resolution limitedly.To end this,this ...Increasing the resolution of seismic data has long been a major topic in seismic exploration.Due to the effect of high-frequency noises,traditional methods could only improve the resolution limitedly.To end this,this paper newly proposed a high-resolution seismic data processing method based on welleseismic combination after summarizing the research status on high resolution.Synthetic record and seismogram are similar in effective signals but dissimilar in noises.Their effective signals are regular and noises are irregular.And they are similar in adjacent frequency.Based on these“three-regularity”characteristics,the relationship between synthetic record and seismogram was established using the neural network algorithm.Then,the corresponding extrapolation algorithm was proposed based on the self-adaptive geological and geophysical variation of multi-layer network structure.And a model was established by virtue of this method and the theoretical simulation was carried out.In addition,it was tested from the aspects of frequency component and amplitude energy recovery,phase correction,regularity elimination and stochastic noise.And the following research results were obtained.First,this new method can extract high-frequency information as much as possible and remain middle and low-frequency effective information while eliminating the noises.Second,in this method,the idea of traditional methods to denoisefirst and then expand frequency is changed completely and the limitation of traditional methods is broken.It establishes the idea of expanding frequency and denoising simultaneously and increases the resolution to the uttermost.Third,this new method has been applied to a variety of reservoir descriptions and the high-resolution processing results have been improved significantly in precision and accuracy.展开更多
In the event of an aircraft crash over the ocean,the potential risk of the Flight Data Recorder(FDR)system sinking to the ocean in conjunction with the aircraft debris is substantial,which would significantly complica...In the event of an aircraft crash over the ocean,the potential risk of the Flight Data Recorder(FDR)system sinking to the ocean in conjunction with the aircraft debris is substantial,which would significantly complicate search and rescue operations.To mitigate this challenge,a separable flight data recorder has been developed by our team which called Emergency Flight Data Recorder(EFDR)system.Encapsulated within a cushioning airbag,the recorder is ejected from the aircraft and decelerates to the sea surface via a deceleration parachute,enhancing both the efficiency of search and recovery operations and the feasibility of flight data analysis.This paper presents an experimental study on the ejection velocity of the ejection system in the EFDR framework,focusing on three critical parameters:airbag material,deceleration parachute placement,and flight data recorder weight.The experimental results indicate that encapsulating the device in an airbag reduces ejection velocity,with fabric airbags inducing a smaller velocity decrement compared to rubber counterparts.Additionally,the deployment of a deceleration parachute further decreases ejection velocity,with a more pronounced reduction observed when the parachute is positioned in front of the projectile than when placed at rear.However,this velocity penalty is deemed acceptable due to the enhanced reliability of parachute deployment in the anterior configuration.Within the counterweight weight range of 2–6 kg,ejection velocity exhibits a marginal decrease with increasing weight,suggesting that variable payloads have a negligible influence on ejection performance.These findings provide empirical insights for the subsequent design optimization of the EFDR system.展开更多
针对目前飞机离地姿态异常的监控依赖单一参数超限探测、缺乏多参数组合异常检测的问题,提出了一种基于近邻搜索空间提取的局部异常因子算法(Isolation-based Data Extracting Local Outlier Factor,IDELOF)的飞机离地姿态异常检测方法...针对目前飞机离地姿态异常的监控依赖单一参数超限探测、缺乏多参数组合异常检测的问题,提出了一种基于近邻搜索空间提取的局部异常因子算法(Isolation-based Data Extracting Local Outlier Factor,IDELOF)的飞机离地姿态异常检测方法。首先,选取空速、俯仰角、滚转角作为飞机离地姿态特征参数,运用基于隔离思想的近邻搜索空间提取方法进行数据降维提取,降低计算复杂度;其次,利用局部异常因子算法对提取后的数据进行异常检测,识别多参综合异常;然后,基于国内某航空公司A319机队297个航班的快速存取记录器(Quick Access Recorder,QAR)数据,验证了模型对单一参数异常和多参综合异常检测结果的有效性;最后,对模型结果的正异常分布特征及可解释性进行分析,分别阐述了八种异常情况出现的主要原因,为飞行安全风险防控提供了深入的数据支持。展开更多
基金Foundation item： National Natural Science Foundation of China （60832012）
文摘Flight data of a twin-jet transport aircraft in revenue flight are analyzed for potential safety problems. Data from the quick access recorder （QAR） are first filtered through the kinematic compatibility analysis. The filtered data are then organized into longitudinal- and lateral-directional aerodynamic model data with dynamic ground effect. The dynamic ground effect requires the radio height and sink rate in the models. The model data are then refined into numerical models through a fuzzy logic algorithm without data smoothing in advance. These numerical models describe nonlinear and unsteady aerodynamics and are used in nonlinear flight dynamics simulation. For the jet transport under study, it is found that the effect of crosswind is significant enough to excite the Dutch roll motion. Through a linearized analysis in flight dynamics at every instant of time, the Dutch roll motion is found to be in nonlinear oscillation without clear damping of the amplitude. In the analysis, all stability derivatives vary with time and hence are nonlinear functions of state variables. Since the Dutch roll motion is not damped despite the fact that a full-time yaw damper is engaged, it is concluded that the design data for the yaw damper is not sufficiently realistic and the contribution of time derivative of sideslip angle to damping should be considered. As a result of nonlinear flight simulation, the vertical wind acting on the aircraft is estimated to be mostly updraft which varies along the flight path before touchdown. Varying updraft appears to make the descent rate more difficult to control to result in a higher g-load at touchdown.
文摘This article studies the fault recorder in power system and introduces the Comtrade format. Andituses C++ programming to read recorded fault data and adopts Fourier analysis and symmetrical component method to filter and extract fundamental waves. Finally the effectiveness of the data processing method introduced in this paper is verified by CAAP software.
文摘Increasing the resolution of seismic data has long been a major topic in seismic exploration.Due to the effect of high-frequency noises,traditional methods could only improve the resolution limitedly.To end this,this paper newly proposed a high-resolution seismic data processing method based on welleseismic combination after summarizing the research status on high resolution.Synthetic record and seismogram are similar in effective signals but dissimilar in noises.Their effective signals are regular and noises are irregular.And they are similar in adjacent frequency.Based on these“three-regularity”characteristics,the relationship between synthetic record and seismogram was established using the neural network algorithm.Then,the corresponding extrapolation algorithm was proposed based on the self-adaptive geological and geophysical variation of multi-layer network structure.And a model was established by virtue of this method and the theoretical simulation was carried out.In addition,it was tested from the aspects of frequency component and amplitude energy recovery,phase correction,regularity elimination and stochastic noise.And the following research results were obtained.First,this new method can extract high-frequency information as much as possible and remain middle and low-frequency effective information while eliminating the noises.Second,in this method,the idea of traditional methods to denoisefirst and then expand frequency is changed completely and the limitation of traditional methods is broken.It establishes the idea of expanding frequency and denoising simultaneously and increases the resolution to the uttermost.Third,this new method has been applied to a variety of reservoir descriptions and the high-resolution processing results have been improved significantly in precision and accuracy.
基金support of Shanghai Central Guide Local Science and Technology Development Funds(YDZX20233100004008)the Fundamental Research Funds for the Central Universities:Key Laboratory of Civil Aviation Emergency Science and Technology CAAC(Grant No.XCA2402202).
文摘In the event of an aircraft crash over the ocean,the potential risk of the Flight Data Recorder(FDR)system sinking to the ocean in conjunction with the aircraft debris is substantial,which would significantly complicate search and rescue operations.To mitigate this challenge,a separable flight data recorder has been developed by our team which called Emergency Flight Data Recorder(EFDR)system.Encapsulated within a cushioning airbag,the recorder is ejected from the aircraft and decelerates to the sea surface via a deceleration parachute,enhancing both the efficiency of search and recovery operations and the feasibility of flight data analysis.This paper presents an experimental study on the ejection velocity of the ejection system in the EFDR framework,focusing on three critical parameters:airbag material,deceleration parachute placement,and flight data recorder weight.The experimental results indicate that encapsulating the device in an airbag reduces ejection velocity,with fabric airbags inducing a smaller velocity decrement compared to rubber counterparts.Additionally,the deployment of a deceleration parachute further decreases ejection velocity,with a more pronounced reduction observed when the parachute is positioned in front of the projectile than when placed at rear.However,this velocity penalty is deemed acceptable due to the enhanced reliability of parachute deployment in the anterior configuration.Within the counterweight weight range of 2–6 kg,ejection velocity exhibits a marginal decrease with increasing weight,suggesting that variable payloads have a negligible influence on ejection performance.These findings provide empirical insights for the subsequent design optimization of the EFDR system.
文摘针对目前飞机离地姿态异常的监控依赖单一参数超限探测、缺乏多参数组合异常检测的问题,提出了一种基于近邻搜索空间提取的局部异常因子算法(Isolation-based Data Extracting Local Outlier Factor,IDELOF)的飞机离地姿态异常检测方法。首先,选取空速、俯仰角、滚转角作为飞机离地姿态特征参数,运用基于隔离思想的近邻搜索空间提取方法进行数据降维提取,降低计算复杂度;其次,利用局部异常因子算法对提取后的数据进行异常检测,识别多参综合异常;然后,基于国内某航空公司A319机队297个航班的快速存取记录器(Quick Access Recorder,QAR)数据,验证了模型对单一参数异常和多参综合异常检测结果的有效性;最后,对模型结果的正异常分布特征及可解释性进行分析,分别阐述了八种异常情况出现的主要原因,为飞行安全风险防控提供了深入的数据支持。
