Zenith Pass Problem of Inter-satellite Linkage Antenna Based on Program Guidance Method

While adopting an elevation-over-azimuth architecture by an inter-satellite linkage antenna of a user satellite, a zenith pass problem always occurs when the antenna is tracing the tracking and data relay satellite （TDRS）. This paper deals with this problem by way of, firstly, introducing movement laws of the inter-satellite linkage to predict the movement of the user satellite antenna followed by analyzing the potential pass moment and the actual one of the zenith pass in detail. A number of specific orbit altitudes for the user satellite that can remove the blindness zone are obtained. Finally, on the base of the predicted results from the movement laws of the inter-satellite linkage, the zenith pass tracing strategies for the user satellite antenna are designed under the program guidance using a trajectory preprocessor. Simulations have confirmed the reasonability and feasibility of the strategies in dealing with the zenith pass problem.     

基于扰动观测器的无人机固定时间编队协同控制

针对无人机的编队控制问题,基于虚拟领航者编队方法,提出了 1种基于固定时间超螺旋干扰观测器的反步控制策略。首先,设计了 1种固定时间超螺旋扰动观测器,以保证在固定时间内,对无人机编队机动所受扰动的快速观测;其次,针对编队控制问题,设计了基于超螺旋扰动观测器的反步控制策略,该控制器显著降低了抖振效应;然后,使用李雅普诺夫理论和固定时间理论,分析了控制策略的固定时间稳定性;最后,通过仿真算例验证了所提出的控制策略的有效性与可行性。     

基于 Nussbaum函数的多无人机预设性能反步容错协同控制

针对多无人机协同执行任务过程中遭遇执行器增益故障下的安全飞行控制问题,设计了 1种预设性能反步容错姿态跟踪控制方案,以实现故障下的多无人机姿态同步跟踪控制。首先,定义飞行器的姿态同步跟踪误差和姿态角速率跟踪误差,分别利用预设性能函数对 2种误差进行约束,将不等式约束转化为等式约束。其次,基于转换误差设计反步容错姿态同步跟踪控制器,应用 Nussbaum函数解决由增益故障引起的未知控制增益问题。Lyapunov稳定性分析表明,姿态同步跟踪误差与姿态角速率跟踪误差稳定且收敛。仿真结果验证了控制方案的可行性以及有效性。     

Modeling and simulation of bow wave effect in probe and drogue aerial refueling

In a probe and drogue aerial refueling system, the bow wave of the receiver aircraft will produce a strong aerodynamic effect on the drogue once the receiver follows the drogue at a close distance. It is a major difficulty of docking control in the probe and drogue refueling. This paper analyses the bow wave effect and presents a simple method to model it. Firstly, the inviscid flow around the receiver is modeled based on the stream function defined by basic stream singularities.Secondly, a correction function is developed to eliminate the error caused by the absence of air viscosity. Then, the aerodynamic coefficients are used to calculate the induced aerodynamic force on the drogue. The obtained model is in an analytical form that can be easily applied to the controller design and the real-time simulations. In the verification part, computational fluid dynamics(CFD)simulation tests are conducted to validate the obtained flow fields and aerodynamic forces. Finally,the modeling method is applied to an F-16 receiver aircraft in a previously developed autonomous aerial refueling simulation system. The simulations results are analyzed and compared with the NASA flight-test data, which demonstrates the effectiveness of the proposed method.     

升力风扇垂直起降无人机死重分析

针对升力风扇垂直起降无人机为了实现垂直起降功能而产生附加的结构重量,以及为加大功率而附加的动力系统重量问题,从总体设计的角度出发,建立了附加重量数学模型,并针对各种设计影响因素进行了分析.研究结果可为升力风扇垂直起降无人机的总体参数设计提供参考.     

浅析飞机烤箱冒烟原因及解决方案

以 B/E 厂家的431系列烤箱为例,分析深航机队中无水型烤箱冒烟的情况,结合一起典型事件通过电路分析确定烤箱冒烟的技术性成因,并提出了相应的解决方案。     

飞翼无人机进舰下滑纵向固有模态特性研究

针对舰载飞翼布局无人机与常规布局飞行器不同的气动外形,建立无人机飞行状态下附近流场的网格模型,并计算了该型无人机的气动参数。基于插值函数计算得出该型无人机的升力系数、阻力系数和俯仰力矩系数对于迎角变化的曲线。建立纵向小扰动方程进行仿真计算,求解出该型无人机在进舰下滑状态时的固有模态特性。计算结果表明,该模型在配平条件下可用于舰载飞翼布局无人机的着舰气动适配性研究。     

伴飞诱饵支援条件下无人飞行器协同作战效能研究

针对复杂的威胁环境，介绍了伴飞诱饵在体系作战条件下的应用情况；基于排队论的突防概率模型，研究了伴飞诱饵支援条件下，无人飞行器的协同突防概率和效费比：提出了作战体系作战时效性的概念；建立了火力对抗条件下无人飞行器打击防空导弹防御体系的Lanchester方程，利用所建模型分析了伴飞诱饵对作战时效性的贡献。研究表明，排队论和Lanchester方程用于伴飞诱饵条件下的无人飞行器协同作战效能研究是有效的。     

直升机加装数据中继设备的设计与分析

直升机因具有低速、机动灵活、起降要求低等特点而得到广泛使用,而空中数据中继转发设备的加改装将进一步拓展直升机任务面。基于某型直升机加装空中数据中继转发站的实际工作,对加改装设计过程进行分析,计算了各部件安装后的受力强度,给出了加装设备结构强度和质心的计算方法,并对加装设备与直升机的电磁兼容性能和设备本身的通信性能进行了分析。结果表明,空中数据中继转发站加装后符合法规要求的结构强度和电磁兼容性等适航要求,且通信性能满足超视距数据中继任务要求。因此,该项工作可为同类型改装工作提供参考和借鉴。     

Aircraft robust multidisciplinary design optimization methodology based on fuzzy preference function

This paper presents a Fuzzy Preference Function-based Robust Multidisciplinary Design Optimization (FPF-RMDO) methodology. This method is an effective approach to multidisciplinary systems, which can be used to designer experiences during the design optimization process by fuzzy preference functions. In this study, two optimizations are done for Predator MQ-1 Unmanned Aerial Vehicle (UAV): (A) deterministic optimization and (B) robust optimization. In both problems, minimization of takeoff weight and drag is considered as objective functions, which have been optimized using Non-dominated Sorting Genetic Algorithm (NSGA). In the robust design optimization, cruise altitude and velocity are considered as uncertainties that are modeled by the Monte Carlo Simulation (MCS) method. Aerodynamics, stability and control, mass properties, performance, and center of gravity are used for multidisciplinary analysis. Robust design optimization results show 46% and 42% robustness improvement for takeoff weight and cruise drag relative to optimal design respectively.