数据传输卡插拔互换性技术探讨

介绍了数据传输卡(DTC)插拔互换性技术有关的几个问题。在产品有使用延续性要求的限制下,在不提高原零部件制造精度和不改变原装配方式的条件下,提出了按照模拟量传递原则而建立的标准体系——装配检验对合平台,并以此在生产中实施,满足了产品使用互换性要求。同时提出了一种新型弹顶组件的设计,使弹顶位置更合理,弹顶更可靠,从而进一步提高了产品插拔可靠性。     

JMASS环境下的飞行仿真组件集成研究

简要介绍了联合建模与仿真系统(JMASS)的基本概念,分析了JMASS的结构和组成。进一步以一个飞行仿真组件的集成为实例,阐述了如何进行基于JMASS仿真环境的仿真子系统开发,特别研究了如何给已有仿真组件增加设计专门针对JMASS环境而的接口的技术,使现有组件能够顺利集成到JMASS环境下,并使之正确运行。     

GNSS global real-time augmentation positioning: Real-time precise satellite clock estimation,prototype system construction and performance analysis

Lots of ambiguities in un-differenced (UD) model lead to lower calculation efficiency, which isn’t appropriate for the high-frequency real-time GNSS clock estimation, like 1 Hz. Mixed differenced model fusing UD pseudo-range and epoch-differenced (ED) phase observations has been introduced into real-time clock estimation. In this contribution, we extend the mixed differenced model for realizing multi-GNSS real-time clock high-frequency updating and a rigorous comparison and analysis on same conditions are performed to achieve the best real-time clock estimation performance taking the efficiency, accuracy, consistency and reliability into consideration. Based on the multi-GNSS real-time data streams provided by multi-GNSS Experiment (MGEX) and Wuhan University, GPS + BeiDou + Galileo global real-time augmentation positioning prototype system is designed and constructed, including real-time precise orbit determination, real-time precise clock estimation, real-time Precise Point Positioning (RT-PPP) and real-time Standard Point Positioning (RT-SPP). The statistical analysis of the 6 h-predicted real-time orbits shows that the root mean square (RMS) in radial direction is about 1–5 cm for GPS, Beidou MEO and Galileo satellites and about 10 cm for Beidou GEO and IGSO satellites. Using the mixed differenced estimation model, the prototype system can realize high-efficient real-time satellite absolute clock estimation with no constant clock-bias and can be used for high-frequency augmentation message updating (such as 1 Hz). The real-time augmentation message signal-in-space ranging error (SISRE), a comprehensive accuracy of orbit and clock and effecting the users’ actual positioning performance, is introduced to evaluate and analyze the performance of GPS + BeiDou + Galileo global real-time augmentation positioning system. The statistical analysis of real-time augmentation message SISRE is about 4–7 cm for GPS, whlile 10 cm for Beidou IGSO/MEO, Galileo and about 30 cm for BeiDou GEO satellites. The real-time positioning results prove that the GPS + BeiDou + Galileo RT-PPP comparing to GPS-only can effectively accelerate convergence time by about 60%, improve the positioning accuracy by about 30% and obtain averaged RMS 4 cm in horizontal and 6 cm in vertical; additionally RT-SPP accuracy in the prototype system can realize positioning accuracy with about averaged RMS 1 m in horizontal and 1.5–2 m in vertical, which are improved by 60% and 70% to SPP based on broadcast ephemeris, respectively.     

大涵道比涡扇发动机涡轮过渡流道一体化设计研究

为了提高大涵道比涡扇发动机气动性能,降低其燃油消耗与污染物排放,同时考虑成本与重量因素,针对其高、低压涡轮之间的过渡流道,提出了一体化概念,即新设计的支板代替原型整流支板与低压涡轮第一级导叶,使其也能够为下游转子提供合适的进气条件。对一算例开展了设计工作,并通过数值模拟进行了流场分析,结果表明带一体化支板涡轮过渡流道与原型涡轮过渡流道出口马赫数与切向速度吻合很好,验证了一体化设计的有效性。带一体化支板的过渡流道设计点工况总压损失为4.3%,较原型流道总压损失略有增大(原型流道总压损失4.1%),但带一体化支板的过渡流道更能适应非设计点工况,具有一定的优越性。     

某细长涡轮轴加工工艺研究

以某细长涡轮轴的加工为研究对象,从加工工艺性、刀具选择、工艺方案等几个方面进行了阐述,并针对加工过程中遇到的问题,提出了解决方案,形成了合理的加工工艺流程,并经过实践验证,值得推广应用。     

A novel in-plane mode rotary ultrasonic motor

Ultrasonic motors have the merits of high ratio of torque to volume, high positioning precision, intrinsic holding torque, etc., compared to the conventional electromagnetic motors. There have been several potential applications for this type of motor in aerospace exploration, but bearings and bonding mechanism of the piezoelectric ring in the motors limit the performance of them in the space operation conditions. It is known that the Langevin type transducer has excel- lent energy efficiency and reliability. Hence using the Langevin type transducer in ultrasonic motors may improve the reliability of piezoelectric motors for space applications. In this study, a novel in-plane mode rotary ultrasonic motor is designed, fabricated, and characterized. The proposed motor operates in in-plane vibration mode which is excited by four Langevin-type bending vibra- tors separately placed around a ring-shaped stator. Two tapered rotors are assembled to the inner ring of the stator and clamped together by a screw nut. In order to make the motor more stable and convenient to fix, a thin cylindrical support is placed under the stator ring. Due to its no-bearing structure and Langevin transducer excitation, the prototype ultrasonic motor may operate well in aeronautic and astronautic environments.     

脉冲爆震火箭发动机同轴喷注器实验研究

为了使液态燃料在脉冲爆震火箭发动机爆震室内形成雾化均匀的小液滴,并且与气态氧化剂掺混后形成空间分布均匀的混合气,设计了适用于脉冲爆震火箭发动机的气液同轴剪切式喷注器。实验研究了三种喷注器结构对脉冲爆震发动机工作过程的影响,结果表明,采用同轴剪切式喷注器的脉冲爆震发动机在20Hz能够产生稳定、连续和充分发展的爆震波。实验中发现,在同时满足雾化良好以及爆震室填充均匀的条件下,喷注器的出气口存在一个最佳面积,实验研究中喷注器出气口的最佳直径在12mm左右。