飞机重量平衡手册的编制探究

初步研究了飞机重量平衡手册的编制规章依据、编写规范和编写方法,通过对ATA2200及S1000D相关标准的研究,为我国民机重量平衡手册的编制提出建议。     

一种新型的用于深空高动态微弱信号载波跟踪环

分析了深空通信中高动态微弱信号载波跟踪方法，提出并分析了载波跟踪中状态方程非线性与量测方程的非线性取舍问题，分析了滤波过程中影响高动态与低信噪比的决定因素，给出了两个推论，提出了强跟踪算法的必要性。并以此选择了以传统卡尔曼滤波（KF）为基础，以锁相环（FLL）、无迹卡尔曼滤波（UKF）为辅助使用两种工作模式来应对不同环境。针对组合跟踪环路状态转换过渡易出现的频率阶跃问题，给出新型环路的工作模式及切换门限的数学表达式，在环路中添加计算判别器，实时控制环路输出的同时不浪费计算力地剔除了野值，提高了环路稳定性。仿真表明，该新型环路算法与现有的算法相比有很好的低信噪高动态适应能力，消除了切换峰值，剔除了野值。     

大型伞绳帆和抽打现象连续模型及验证

文章主要推导了可用于描述大型降落伞绳帆和抽打现象的一般绳索三维动力学连续模型,及弦坐标系下可用于求解绳帆现象的两点边值问题(BVP)模型,并采用某型号大型降落伞的空投录像和杆件算例对模型进行验证对比,说明了模型的正确性,采用这一连续模型能够更直观地对大型伞的绳帆和抽打现象进行定性和定量分析。     

民航运输机最大起飞重量和起飞速度的确定

重点论述了限制最大起飞重量的因素和起飞速度的选择方法,并以Citation Jet 1(CJ-1)飞机为例,分析了飞机在昆明/巫家坝机场起飞时限制最大起飞重量的主要因素,给出了CJ-1飞机确定最大起飞重量和起飞速度的分析方法和起飞性能分析表,为部分支线客机和公务机进行起飞分析并确定起飞分析表的内容、结构和形式提供了参考。     

烟支重量控制系统的模糊PID控制器设计

针对传统的娴支重量控制系统响应速度慢、重量偏差大等问题,提出了烟支平均重量的模糊PID控制算法,给出了该算法的详细描述,控制器用平均重赶的偏差和变化率来维持一个恒定的输出烟支重量。仿真结果表明,该控制系统具有调整时间短、稳态误差小、超调量小,采用模糊PID控制器比采用传统的PID控制器可以得到更好的动态响应性能和控制精度。     

低热值气体燃料燃烧室数值模拟与试验研究

以某型航空发动机燃烧室为研究对象,对低热值燃料燃烧室进行了数值模拟和试验研究。采用RNGk-ε模型、小火焰紊流燃烧模型和P-1辐射模型,预估了紊流特性、化学反应速率和辐射通量;应用SIMPLE算法,对离散方程进行求解。计算结果与试验数据比较表明二者基本吻合,这说明计算方法合理,可用来估算低热值燃料燃烧室的燃烧性能。     

利用极值分布概型预测海峡地区风环境期望风速

根据《公路桥梁抗风设计规范》,对于特别重要的桥梁要求对桥址处的设计基本风速进行重新观测或参考实测风速样本进行推算得到,选取合理的基本设计风速.本文选取厦门一漳州跨海大桥附近的厦门市专业气象台和龙海市气象局360个月的极值10分钟平均时距的风速和风向标准值,采用3种极值分布概型推算出不同重现期内的设计风速.得出了厦门海峡桥址处100年一遇的期望风速为35.8 m/s,小于规范给出的厦门地区100年一遇基本设计风速39.7m/s.     

Comparison of hindlimb unloading and partial weight suspension models for spaceflight-type condition induced effects on white blood cells

Animal models are frequently used to assist in the determination of the long- and short-term effects of space flight. The space environment, including microgravity, can impact many physiological and immunological system parameters. It has been found that ground based models of microgravity produce changes in white blood cell counts, which negatively affects immunologic function. As part of the Center of Acute Radiation Research (CARR), we compared the acute effects on white blood cell parameters induced by the more traditionally used animal model of hindlimb unloading (HU) with a recently developed reduced weightbearing analog known as partial weight suspension (PWS). Female ICR mice were either hindlimb unloaded or placed in the PWS system at 16% quadrupedal weightbearing for 4 h, 1, 2, 7 or 10 days, at which point complete blood counts were obtained. Control animals (jacketed and non-jacketed) were exposed to identical conditions without reduced weightbearing. Results indicate that significant changes in total white blood cell (WBC), neutrophil, lymphocyte, monocyte and eosinophil counts were observed within the first 2 days of exposure to each system. These differences in blood cell counts normalized by day 7 in both systems. The results of these studies indicate that there are some statistically significant changes observed in the blood cell counts for animals exposed to both the PWS and HU simulated microgravity systems.     

大型客机先进翼尖装置综合特性研究

 翼尖装置由于其良好的气动特性在航空界得到了广泛应用,然而它也使飞机的颤振及结构重量特性发生了变化。为了探求翼尖装置的综合特性,利用数值模拟方法对大型客机上最先进的3种翼尖装置(融合式、鲨鱼鳍式和阶梯式)进行了气动、颤振及重量3个方面的综合研究。3种翼尖装置减阻效果明显,但同时结构重量亦增加。翼尖装置均降低了机翼颤振速度。研究结果表明:加装翼尖装置后机翼颤振形态取决于翼尖装置的形式。相对于机翼颤振速度,翼尖装置形式对机翼颤振速度的影响是小量(1%~7%),且翼尖装置减阻和机翼压心外移的综合重量增益,为机翼结构设计提供了一定的设计空间。     

An Adaptive Weighted Differential Game Guidance Law

For intercepting modern high maneuverable targets, a novel adaptive weighted differential game guidance law based on the game theory of mixed strategy is proposed, combining two guidance laws which are derived from the perfect and imperfect information pattern, respectively. The weights vary according to the estimated error of the target’s acceleration, the guidance law is generated by directly using the estimation of target’s acceleration when the estimated error is small, and a differential game guidance law with adaptive penalty coefficient is implemented when the estimated error is large. The adaptive penalty coefficients are not constants and they can be adjusted with current target maneuverability. The superior homing performance of the new guidance law is verified by computer simulations.