LDRA TESTBED在航天软件测试中的应用

提出采用LDRA(Liverpool Data Research Associates Ltd.)TESTBED测试工具辅助完成高可靠性的军用软件测试工作,并通过测试实例阐述了该工具在航天软件测试中的应用方案。结果证明,合理使用该工具,能够有效避免人为失误,提高软件测试的效率和信息采集的准确度。     

Shape error study of inflatable antennas using a numerical model

We conduct an in-depth study on the shape error of initially curved antennas to investigate errors that occur in the design and manufacturing processes. First, a numerical model is developed to simulate the actual surfaces. This model features a main advantage that it can predict the effects of cutting patterns on the shape error. The model is used to evaluate and optimize the design of cutting patterns. An error sensitivity analysis is performed to quantify and distinguish between the effects of error sources in manufacturing. The following sources are analyzed: errors in the elastic modulus of the membrane, pressure variations, and boundary deviations. The boundary deviation is found to be the most significant error source, and thus, boundary perturbation is recommended as an efficient error control measure. Finally, an inflatable antenna model is used to experimentally validate the numerical model. The experimental results display acceptable agreement with the numerical results. Thus, the developed numerical model and error control measure are shown to be feasible and efficient.     

Experimental study on rotary ultrasonic vibration assisted drilling rock

Traditional rotary ultrasonic vibration drilling rock (f_z < 2A) is an effective drilling rock method, but its feed rate is limited by the ultrasonic vibration amplitude, resulting in lower drilling efficiency. In this paper, based on the requirements of drilling efficiency in the asteroid sampling mission, the process method of rotary ultrasonic vibration assisted drilling rock (f_z > 2A) was proposed. The mechanism of ultrasonic vibration assisted drilling rock was analyzed, and the propagation of ultrasonic energy in the process of ultrasonic vibration assisted drilling rock was analyzed. Using the small diameter cemented carbide triangular bit as the drilling tool, the comparative test of ultrasonic vibration assisted drilling and traditional drilling of sandstone, marble, and basalt was carried out. The experimental results showed that there was a specific feed rate range for each type of rock, so that the weight on bit required for ultrasonic vibration assisted drilling was less than that of traditional drilling. With the increase of firmness coefficient of sandstone, marble, and basalt, the ratio of weight on bit to feed rate was increased, and the effective feed rate range of ultrasonic vibration assisted drilling was reduced. The ultrasonic vibration assisted drilling rock (f_z > 2A) was one of the alternative methods for drilling rock on the asteroid surface.     

地月低能轨道转移的混沌控制方法

针对航天器在混沌区域的滑行时间过长，提出一种低能地月轨道转移的混沌控制方法。首先通过地月圆形限制性三体问题(CRTBP)的庞加莱截面图，将混沌区域进行分层并分析其规律，再利用混沌轨道对初始状态高度敏感的特性，在尽可能减少运送时间的前提下实现地月低能轨道转移。该方法的优点是利用混沌区域的固有规律，不需要依靠周期轨道特性。仿真结果表明，本文提出方法仅需施加2~4次脉冲，明显缩短混沌区域的滑行时间，从而实现地月低能转移。     

基于变论域模糊控制算法的仿真与FPGA优化实现

针对单力臂模型的复杂动力学行为，设计了一种不依赖于被控对象的精确数学模型的变论域模糊控制器。在闭环系统中，角位移量的跟踪偏差和其变化率作为系统输入，并将控制器的初始论域设为［-3，3］，其值可通过伸缩因子来调节。基于Matlab软件仿真，验证单力臂模型对预期指令的跟踪性能。另外，基于现场可编程门列阵(FPGA)硬件，采用移位操作和分段线性化两种方法对控制器进行优化。由此，无乘法器和片上内存零占用的设计结构显著降低了硬件资源负担。实验结果表明:本文所提变论域模糊闭环控制方法在精确度(低于0.02)、自适应性以及实时性等方面性能较优越，具有一定工程应用价值。     

冷却空气管供气腔脉冲射流流动响应特性实验研究

为了探究脉冲射流经航空发动机主动控制系统中冷却空气管内的流动响应规律，本文对单排40个出流孔的冷却空气管内的脉冲射流流动响应特性进行了实验研究。同时，引入了响应时间、迟滞时间和出流速度系数三个评价参数，对脉冲射流在冷却空气管内的响应特性进行定量分析。实验重点分析了脉冲频率f（1Hz~20Hz）、进口雷诺数Re（5000~20000）等参数变化对流动响应特性带来的影响。研究发现，在一个脉冲周期内，冷却空气管出流速度的响应时间和迟滞时间沿程逐渐增加，出流速度系数沿程变化不大。在本文实验参数范围内，f和Re增加，冷却空气管出流响应时间、迟滞时间所占脉冲周期的比例和出流速度系数逐渐增加。f、Re越大，冷却空气管内压力越大，流容越小。     

原子层沉积纳米钝化层薄膜厚度测量技术研究

原子层沉积无机纳米薄膜技术广泛应用于军民领域。本文通过在原子层沉积系统加装原位石英晶体微天平测量系统，通过原位石英晶体微天平研究原子层沉积无机薄膜生长过程并进行薄膜厚度的在线测量。通过研究原子层沉积反应条件，实现原子层沉积无机薄膜厚度的石英晶体微天平在线测量结果替代薄膜厚度线下光学测量结果，解决各类复杂腔体内壁原子层沉积薄膜厚度无法精确测量的问题。     

过盈配合应力分布超声测量与连接力预测

为了实现过盈配合应力分布的测量和连接力预测,以超声波脉冲反射法原理为基础,建立了超声测量系统及标定装置。首先,利用标定装置对反射系数的影响因素进行了分析。然后,用所搭建的超声测量系统测量了3种过盈量(6μm,12μm和18μm)的应力分布,并根据测量结果实现了连接力的预测。最后,通过压出实验对预测结果进行了验证。研究表明,耦合剂、粗糙度的大小和纹理方向及覆型边界是影响测量精度的关键因素。本文建立的覆型边界误差分析模型可以实现测量误差的预测及补偿。应力分布测量结果能够有效反应配合面间的接触状态及缺陷,连接力的相对误差小于16%。因此,本文所建立的分析方法和测量系统可以实现应力分布的准确测量与连接力的可靠预测,并为过盈组件配合质量与连接力的可靠评估提供了技术支撑。此外,本文的研究方法具有普遍的适用性,对实现不同接触面间应力的测量具有一定的指导意义。     

旋翼式火星无人机技术发展综述

火星表面稀薄的大气环境为旋翼式无人机在火星低空飞行提供了必要的条件。概述了火星无人机的研究背景、飞行环境与研制难点；整理了世界范围内各研究机构研制的旋翼式火星无人机的技术特点；梳理旋翼式火星无人机研究在气动特性理论、低气压飞行控制、系统集成等方面的关键技术；总结旋翼式火星无人机的仿真研究与实验研究成果；对火星无人机未来的发展趋势进行展望。