基于空基平台的激光通信技术研究和展望

深低温阀门多为常温设计，低温服役。宽温域引起的结构变形将诱发阀门导向卡滞、密封泄漏等安全问题。采用有限元分析方法获取阀门导向副配合部位变形量，提出迭代镜像补偿方法解决深低温服役的阀门导向副变形超差问题。经分析，在深低温工况下阀门配合间隙均超出设计允许值，导向行程最大时配合间隙减小17.95%至16.41 μm；补偿后导向副配合间隙变形量控制在1 μm内，满足深低温工况下阀门形状设计要求，验证了迭代镜像补偿方法的有效性。     

Maneuver control at high angle of attack based on real-time optimization of integrated aero-propulsion

To reduce the propulsion system installation thrust loss under high angle of attack maneuvering, a control method based on real-time optimization of the integrated aero-propulsion is proposed. Firstly, based on data fitting and physical principle, an integrated onboard model of propulsion system is established, which can calculate various performance parameters of the propulsion system in real time, and has high accuracy and real-time performance. Secondly, to improve the compatibility of optimization real-time performance and search accuracy, the online optimization control of aero-propulsion system is realized based on an improved trust region algorithm. Finally, by controlling the auxiliary intake valve, a good match between inlet and engine is realized, which solves the problems of intake flow reducing and total pressure recovery coefficient declining, and improves the installation performance of propulsion system. The simulation results indicate that, compared with the conventional independent engine control, the real-time integrated optimization method reduces the installed thrust loss by 3.61% under the design condition, and 4.58% under the off-design condition. Furthermore, the simulation on HIL (Hardware-In-the-Loop) platform verifies the real-time performance of integrated optimization method.     

润滑系统调压差活门技术研究与应用

调压差活门为发动机滑油供油系统的重要部件,用于控制滑油的流量和压力,关系着航空发动机润滑系统的供油能力和工作稳定性,通过感受供油路压力和中轴承腔压力保证各喷嘴前后的压差稳定在规定的范围内。为掌握某型发动机调压差活门的工作特性,对调压差活门的开闭特性、流量特性及响应特性进行试验研究。结果表明:活门的打开压力为252 k Pa,响应时间小于384 ms。研究结果可应用于生产中调压差活门初始打开压力的设定以及后续滑油供油系统仿真分析中,以提高航空发动机滑油供油系统流量、压力仿真计算的准确性和真实性。     

某航空活塞发动机机械增压器旁通阀门开启特性分析

机械增压器现已在汽车发动机上得到了广泛应用,但其在航空活塞发动机上的应用和研究较少.分析机械增压器的工作过程,在簧片阀模型的基础上,考虑旁通阀门启闭压力与涡轮增压器压比之间的线性关系并对其建模;搭建某型航空活塞发动机GT-POWER数值仿真模型并进行实验验证,在整机模型的基础上,研究不同转速下通过旁通阀门的质量流率以及不同高度下旁通阀门的通流面积.结果表明:巡航工况下,海拔2680 m时阀门关闭;起飞工况下,海拔3000 m阀门关闭,该结果可为发动机实际高空飞行提供理论支持.     

一种基于状态反馈的比例伺服阀控制方法

在电液比例伺服阀中，液动力存在较强的非线性，开环控制下驱动电流与阀芯位移的线性度较差，使用传统PID控制算法难以达到良好控制效果。针对该现象，在分析阀芯液动力特性的基础上，提出了一种位置负反馈式的控制方法。通过搭建比例伺服阀的控制器模型和阀芯受力模型，开展试验验证。结果表明该方法能够有效地解决了控制中的电流—阀芯位移的非线性问题，控制稳定性有明显的提升。     

Pneumatic pressure control based on improved NMPC and its application to aeroengine surge simulation

In the semi-physical simulation of aeroengines, using the pneumatic pressure servo control technology to provide realistic pneumatic excitation to the sensors and electronic controller can improve the confidence of the simulation and reduce the test cost and risk. However, the existing methods could not satisfy the precise simulation of large-amplitude and high-frequency pulsating pressure during aeroengine surge. In this paper, a pneumatic pressure control system with asymmetric groups of the High-Speed on–off Valve (HSV) is designed, and an Improved Nonlinear Model Predictive Control (INMPC) method is proposed. First, the volumetric flow characteristics of HSV are tested and analyzed with Pulse Width Modulation (PWM) signal input. Then, a simplified HSV model with the volume flow characteristic correction is developed. Based on these, an integrated model for the whole system is further established and used as the prediction model in INMPC. To improve the computational speed of the rolling optimization process, the mapping scheme from control signal to PWM duty cycle of HSVs and the objective function with exterior penalty function are designed. Finally, the random step, sinusoidal and real engine surge data are set as the reference pressure in multiple comparative experiments to verify the effectiveness of the pressure tracking system.     

加工装配误差影响下偏转射流压力伺服阀静态特性分析

电液压力伺服阀是电液压力伺服控制系统的核心控制元件，广泛应用于航空、航天、军事等领域。区别于流量伺服阀，压力伺服阀在滑阀放大器的设计上多采用带有压力控制容腔的三通阀结构，不同的滑阀结构使得现有的偏转射流流量伺服阀仿真模型难以满足压力伺服阀性能预测的需求。本文基于AMESim平台建立了偏转射流压力伺服阀的仿真模型，并通过实验对仿真模型进行了验证，验证结果表明仿真模型能够准确地描述压力伺服阀的静态特性。最后，通过仿真模型分析了加工装配误差影响下压力伺服阀输出性能差异，仿真结果可为偏转射流压力伺服阀的性能预测和结构设计提供参考。     

民用飞机刹车系统CCAR 25.735条款适航研究

介绍了民用飞机适航规章CCAR-25-R4最新版并与前一版本R3版在刹车系统主条款25.735条进行对比分析，详细解释了R4版与R3版的不同之处及更改原因，阐述了R4版735条的详细要求，提供了刹车系统的适航思路及符合性方法建议。最后进行了小结并提出了下一步目标。     

航空发动机放气活门随动杆断裂故障分析

某航空发动机防喘系统的放气活门随动杆与放气活门控制杆相连接,将防喘调节系统的运动传递给随动杆的拨叉,操纵放气活门的启闭。随动杆断裂将导致发动机的防喘系统失效,直接影响发动机的安全使用。针对放气活门随动杆多次出现断裂故障问题,根据放气机构结构特点和随动杆断裂处安装环境和工作方式,对随动杆进行动应力测试及分析,结果表明:放气机构运行不正常会使放气机构零件磨损,从而使随动杆承受大的振动应力和冲击应力,振动应力和冲击应力的叠加作用是导致随动杆断裂的主要原因,为该故障诊断提供依据。