微型飞行器优化设计及气动特性分析

微型飞行器(MAV)气动布局形式是影响其飞行性能指标的关键因素之一。从总体角度出发，设计出三种不同气动布局的MAV，并对其进行了优化设计和气动特性分析。研究结果对MAV气动布局的设计有一定的指导意义。     

X型尾翼布局对无人机静稳定性的影响

针对某型无人机所采用的X型尾翼布局,利用求解三维Euler方程的数值计算方法,得到了不同尾翼夹角和安装角状态下的全机纵向及横航向力矩值,并以此分析和研究了X型尾翼的夹角和安装角对无人机纵向及横航向静稳定性的影响。在此基础上,根据飞机的静稳定性要求,确定了该型无人机的尾翼夹角及安装角。     

油品静电评价及防护对策

分析了油品在管道中静电起电的因素,在此基础上,采用Fuzzy评价方法,建立了油品静电评价模型。最后提出了消除油品静电的方法。     

燃机排气装置扩压器的设计和试验研究

本文对燃机排气装置扩压器进行了试验研究。针对一个正在使用中的排气装置,测定其原型的性能,而后在原型外壳尺寸一定的条件下,采用本文所推荐的两种形式的燃机轴径式扩压器型面设计方法,一种为等角扩压器,一种为带中间收敛的扩压器,并进行了试验验证。试验结果表明,采用所提出的方法设计的扩压器性能较好,能显著改善排气装置的性能。但由于受到原扩压器外壳尺寸的限制,上述两种扩压器设计方法的优越性未能得到充分发挥,文中只能作相对比较。本文所推荐的燃机排气扩压器的设计方法对工程应用具有实际参考价值。     

风力机塔架结构风振试验的模化方法

本文讨论了风力机塔架相似模型的建立,并把强风瞬时风速记录变换为符合相似条件的风模型。采用激振器对塔架模型做模拟风激振试验以及在静风荷载作用下塔架模型的光弹终验。上述工作组成了完整的风致结构振动的模化实验方法。     

基于乘波体的高超音速运载器气动布局设计

采用基于无粘锥形流的反设计方法以Ma=6为设计点设计具有高升阻比的乘波体外形;取基准圆锥激波角为12°,并利用上表面的膨胀降压作用,这一外形优化有效提高了乘波体的升阻特性,在考虑粘性影响的情况下Ma=6时的升阻比可从3.356?3提高到4.598?1;将具有高升低阻效能的乘波体作为机身初步设计单级入轨运载器布局,通过数值模拟的方法进行研究,结果表明布局在大速度范围内的升阻比得到了令人满意的结果,同时具备静稳定性.     

基于Windows系统环境下的精确定时过程实现

首先阐述Windows系统环境下的消息处理机制；然后对Windows下几种常用精确定时器进行比较；最后设计一种基于多线程技术的高精度定时器。通过实际测试，验证了该定时器的高精度性能，很好地实现了以毫秒级定时的通信任务。     

电传系统设计研究

研究了纵向电传系统前向指令回路非线性校正、过载指令的设计和综合、C*反馈回路的设计、调参规律的选取、校正网络特征、闭环系统稳定性、闭环系统相位补偿以及放宽静安定度补偿方法等,并对伺服弹性回路和人-机耦合回路的综合设计进行了研讨。     

The GFZ real-time GNSS precise positioning service system and its adaption for COMPASS

Motivated by the IGS real-time Pilot Project, GFZ has been developing its own real-time precise positioning service for various applications. An operational system at GFZ is now broadcasting real-time orbits, clocks, global ionospheric model, uncalibrated phase delays and regional atmospheric corrections for standard PPP, PPP with ambiguity fixing, single-frequency PPP and regional augmented PPP. To avoid developing various algorithms for different applications, we proposed a uniform algorithm and implemented it into our real-time software. In the new processing scheme, we employed un-differenced raw observations with atmospheric delays as parameters, which are properly constrained by real-time derived global ionospheric model or regional atmospheric corrections and by the empirical characteristics of the atmospheric delay variation in time and space. The positioning performance in terms of convergence time and ambiguity fixing depends mainly on the quality of the received atmospheric information and the spatial and temporal constraints. The un-differenced raw observation model can not only integrate PPP and NRTK into a seamless positioning service, but also syncretize these two techniques into a unique model and algorithm. Furthermore, it is suitable for both dual-frequency and sing-frequency receivers. Based on the real-time data streams from IGS, EUREF and SAPOS reference networks, we can provide services of global precise point positioning (PPP) with 5–10 cm accuracy, PPP with ambiguity-fixing of 2–5 cm accuracy, PPP using single-frequency receiver with accuracy of better than 50 cm and PPP with regional augmentation for instantaneous ambiguity resolution of 1–3 cm accuracy. We adapted the system for current COMPASS to provide PPP service. COMPASS observations from a regional network of nine stations are used for precise orbit determination and clock estimation in simulated real-time mode, the orbit and clock products are applied for real-time precise point positioning. The simulated real-time PPP service confirms that real-time positioning services of accuracy at dm-level and even cm-level is achievable with COMPASS only.     

湿滑道面飞机轮胎临界滑水速度计算方法比较

以美国国家航空航天局(NASA)临界滑水速度计算公式为基础,基于耦合欧拉-拉格朗日(CEL)算法建立动流场冲击原地转动轮胎分析模型,并由NASA公式及试验数据验证了模型的正确性及NASA公式在重轴载高胎压范围的适用性。进而考虑实际道面积水状态,建立滚动轮胎冲击静流场模型,探讨实际积水状态对临界滑水速度的影响。通过两类模型对比分析得出:两类模型的轮胎-水膜相互作用机理不同,相同速度和胎压下,后者在轮胎前缘形成的动水压强峰值明显高于前者,表明滚动轮胎冲击静流场模型中轮胎受到动水压强抬升作用更为显著,且相同速度条件下,滚动轮胎冲击静流场分析模型计算的竖向支撑力和临界滑水速度始终低于动流场冲击滚动轮胎的结果,表明该模型计算结果偏于安全,更适用于飞机高速滑行中轮胎-水膜相互作用分析。据此,提出了基于道面积水状态的临界滑水速度计算公式。