基于Origin语言的某型教练机发动机燃油系统故障诊断与分析

某型教练机在低空大表速飞行时,其发动机在最大状态下的供油量超过了发动机在各个状态的最大燃油流量软件值（GT=2300kg／h）,发动机从主燃油流量控制转为发动机应急流燃油量控制。本文对发动机色行数据进行了深入分析,同时结合发动机的三大特性,对其控制系统软件进行更改,经过后续飞行验证．发动机燃油控制系统下作正常。     

涡轴发动机/直升机综合控制仿真平台设计

建立了UH-60直升机/T700涡轴发动机综合控制数字仿真平台。基于VC++环境开发了包含UH-60直升机/T700涡轴发动机综合实时模型的上位机程序,与运行机载涡轴发动机+旋翼实时模型及在线优化控制模式的下位机程序。两者基于TCP/IP协议实时通讯,可进行模拟实际直/发综合优化控制的数字仿真实验。在该数字仿真环境下,分别给出了提高直升机常规飞行性能的多种优化控制模式仿真、变旋翼转速优化控制以及快速功率跟随控制模式仿真,充分表明该平台可为新一代直/发综合系统的开发研制提供一个可靠的前期数字仿真验证。     

一种基于FFT的Galileo搜救信号频域检测方法

Galileo搜救系统是全球卫星搜救组织(COSPAS-SARSAT)的一部分,搭载于Galileo导航星座,能对遇险用户发出的求救信号进行定位并实施救援。经卫星转发的搜救信号信噪比很低,能否在低信噪比条件下完成卫星信号的检测对搜救系统的正常工作至关重要。为了解决这一问题,文章提出了一种基于快速傅里叶变换(FFT)运算的频域检测方法,通过理论分析和仿真验证可以看出,这种方法能有效地实现低信噪比条件下的卫星下行信号检测。     

Evaluation method for helicopter maritime search and rescue response plan with uncertainty

Helicopter plays an increasingly significant role in Maritime Search and Rescue (MSAR), and it will perform MSAR mission based on response plans when an accident occurs. Thus the rationality of response plan determines the success of MSAR mission to a large extent. However, with the impact of many uncertainty factors, it is difficult to evaluate response plans comprehensively before performing them. Aiming at these problems, an evaluation framework of helicopter MSAR response plan named UMAD is proposed in this paper, which reveals the influence mechanism of uncertainty factors based on Multi-Agent method and analyzes the mission flow based on Discrete Event System (DEVS) method. Furthermore, the evaluation criterion and indicators of response plan are extracted from the aspects of safety and effectiveness. Meanwhile, the Monte Carlo method is adapted to calculate the probability distribution and robustness of response plan comprehensive result. Finally, in order to illustrate the validity of this method, it is discussed and verified by an application example of evaluating multiple response plans to the same MSAR scenario. The results show that this method can analyze the influence of uncertainty more systematically and optimize response plans more comprehensively.     

Design and Simulation Analysis of Pneumatic Energy Capacity forEmergency Landing Gear Release of an Aircraft

为了完成飞机起落架应急放系统的设计,以某型飞机起落架应急放气压能源容量为研究对象,结合具体设计要求,完成飞机起落架应急放气压能源容量的初步设计。再结合 AMEsim 软件平台建立起落架应急放气动系统的仿真模型,对起落架应急放气压能源容量的设计参数及性能进行仿真分析。结果表明,起落架应急放气压能源容量满足设计要求,可以为飞机起落架应急放气压能源容量的设计提供一些经验和结论。     

空间红外遥感器定标机构故障应急退出装置

针对空间红外遥感器定标机构故障模式,首次设计了一种基于记忆合金的应急退出装置,以解决因电机或控制电路故障而导致的整个成像系统失效问题。该应急退出装置通过对记忆合金棒进行加热,使其受热收缩,从而驱动齿轮传动系统脱离啮合状态,完成机构复位运动。为验证该应急退出装置的功能和性能,利用研制产品进行了真空、大气环境等多种状态下的应急退出试验。结果表明:在大气和真空环境中,该装置能实现多种状态下的可靠退出功能;在28 V额定直流工作电压下,应急退出总时间可达145～152 s。该机构具有实现简便、可靠性高、退出速度快等优点,在空间机构的故障应急方面具有较大的工程应用潜力。     

直升机贴地飞行时的驾驶员诱发振荡研究

主要阐述直或机贴地飞行时的驾驶员诱发振荡问题，导出了贴地突防和迅速停止动作、地形跟踪时的“海豚”运动和贴地飞行时滑雪运动条件下诱发振荡时操纵位移和稳定裕度的计算公式，计算了Ｚ－８直长机的纵向试验结果，并进行了误差分析。计算结果表明，所研究的方法是可行的，可推广应用于各种直升机的闭环分析和计算。     

液氧/煤油发动机地面试验故障紧急关机系统研制

论述了液氧／煤油发动机研制地面试车中，出现故障时所采用的紧急关机系统的原理和系统结构、设计程序、设计指标、关机判断准则、验证及应用等。     

Numerical study on flow control of ship airwake and rotor airload during helicopter shipboard landing

A numerical study on flow control of ship airwake during shipboard landing is carried out to address the effect of flow control devices on helicopter rotor airload. The in-house Reynolds Averaged Navier-Stokes (RANS) based solver Rotorcraft AeroDynamics and Aeroacoustics Solver (RADAS), with combination of momentum source approach is employed to conduct the helicopter shipboard landing simulation. The control effects of three aerodynamic modifications of ship superstructure, i.e. ramp, notch and flap, in different Wind-Over-Deck (WOD) conditions are discussed. From the steady simulation results, the effect of spatial variation of ship airwake on rotor airloads is concluded. The aerodynamic modifications reduce the strength of shedding vortex and increase rotor normal force through delaying and relieving flow separation, and therefore are beneficial to alleviate the limitation of control inputs. By contrast, the perturbation of unsteady ship airwake can cause the serious oscillation of rotor forces during shipboard landing. The unsteady simulations show that the turbulence intensity of ship airwake and oscillatory rotor airloading, represented by Root-Mean-Square (RMS) loading, can be remarkably reduced by the ramp and notch modifications, while the flap modification has adverse effect. It means that flow control devices have large potential benefits to alleviate the pilot’s workload and improve the shipboard landing safety, but they should be well designed to avoid the introduction of more vortex, which leads to increase in disturbance of flow field.     

A multi-criteria fusion feature selection algorithm for fault diagnosis of helicopter planetary gear train

Planetary gear train is a prominent component of helicopter transmission system and its health is of great significance for the flight safety of the helicopter. During health condition monitoring, the selection of a fault sensitive feature subset is meaningful for fault diagnosis of helicopter planetary gear train. According to actual situation, this paper proposed a multi-criteria fusion feature selection algorithm (MCFFSA) to identify an optimal feature subset from the high-dimensional original feature space. In MCFFSA, a fault feature set of multiple domains, including time domain, frequency domain and wavelet domain, is first extracted from the raw vibration dataset. Four targeted criteria are then fused by multi-objective evolutionary algorithm based on decomposition (MOEA/D) to find Proto-efficient subsets, wherein two criteria for measuring diagnostic performance are assessed by sparse Bayesian extreme learning machine (SBELM). Further, F-measure is adopted to identify the optimal feature subset, which was employed for subsequent fault diagnosis. The effectiveness of MCFFSA is validated through six fault recognition datasets from a real helicopter transmission platform. The experimental results illustrate the superiority of combination of MOEA/D and SBELM in MCFFSA, and comparative analysis demonstrates that the optimal feature subset provided by MCFFSA can achieve a better diagnosis performance than other algorithms.