Motor vehicle-bicycle crashes in Beijing: irregular maneuvers, crash patterns, and injury severity

This research presents a comprehensive analysis of motor vehicle–bicycle crashes using 4 years of reported crash data (2004–2007) in Beijing. The interrelationship of irregular maneuvers, crash patterns and bicyclist injury severity are investigated by controlling for a variety of risk factors related to bicyclist demographics, roadway geometric design, road environment, etc.Results show that different irregular maneuvers are correlated with a number of risk factors at different roadway locations such as the bicyclist age and gender, weather and traffic condition. Furthermore, angle collisions are the leading pattern of motor vehicle–bicycle crashes, and different irregular maneuvers may lead to some specific crash patterns such as head-on or rear-end crashes. Orthokinetic scrape is more likely to result in running over bicyclists, which may lead to more severe injury. Moreover, bicyclist injury severity level could be elevated by specific crash patterns and risk factors including head-on and angle collisions, occurrence of running over bicyclists, night without streetlight, roads without median/division, higher speed limit, heavy vehicle involvement and older bicyclists.This study suggests installation of median, division between roadway and bikeway, and improvement of illumination on road segments. Reduced speed limit is also recommended at roadway locations with high bicycle traffic volume. Furthermore, it may be necessary to develop safety campaigns aimed at male, teenage and older bicyclists.     

挠性卫星的姿态机动滚动优化控制

提出了一种基于控制力矩陀螺的挠性卫星姿态大角度快速机动控制方法。结合卫星姿态动力学,运动学和挠性附件的振动方程,建立了面向预测控制方法的非线性预测方程;在建立了包含卫星姿态跟踪误差,控制力矩能量以及挠性附件振动能量的优化目标函数基础上,采用非线性模型预测控制方法设计了兼顾机动性能与抑制附件振动的卫星姿态机动律。为进一步消除挠性附件振动,采用输入成形技术对规划的控制力矩进行处理,成形出合理的控制力矩指令。最后以成形后的控制力矩指令为输入条件,基于鲁棒伪逆方法设计了金字塔控制力矩陀螺群的操纵律,完成挠性卫星姿态机动的非线性滚动控制。针对算例的研究表明:卫星滚动轴姿态能够在约27 s内机动50°,且具有指向精度小于0.03°,姿态稳定度小于0.03(°)/s的性能。     

一种改进的机动目标跟踪算法

针对传统Singer滤波算法,跟踪机动目标精度较低、收敛较慢的问题,提出了一种改进的Singer算法,该算法根据新息的衰减记忆平均值和加速度滤波值,实时调整过程噪声协方差矩阵,改变滤波增益,减小了位置的均方根误差,并提高了速度和加速度的滤波精度,通过Matlab仿真,证明了该算法的可行性。     

论联合机动编队综合电子战

联合机动编队综合电子战要求平衡编队内部电子战能力,注重整体对抗,最大限度发挥联合机动编队各类电子战设备的作战效能,确保我联合机动编队整体安全。     

舰载烟幕防御红外成像制导导弹的发射机动决策方案研究

舰载烟幕是防御红外成像制导导弹的一种有效措施和方法。针对反舰导弹的来袭方位、风向风速,如何确定烟幕的发射方案和本舰规避机动方案,是烟幕防御反舰导弹战术运用需要解决的关键问题。本文在工程化定性分析和分类思想的指导下,基于提出的交点判断和点矢量位置判断准则,给出了获得最优发射机动决策方案的具体过程和步骤。仿真结果和主观定性判断完全一致。依据烟幕防御反舰导弹的最优发射机动决策方案,可以使舰艇在末端防御的情况下,最大可能地赢得生存机会。     

某大机动无人机基于飞行任务的敏捷性评估飞行科目设计与仿真

由于现代空战的特点，根据时间量级分类的单维度的敏捷性评估已经不能满足空战的需求。为了优化控制系统的设计，最大限度地发挥飞机的飞行性能，需要对大机动无人机进行基于飞行任务的敏捷性评估。针对大机动无人机敏捷性评估的特点，从20个标准评估机动任务集中选取了3种与某无人机实际使用相关性较强的飞行任务作为其评估机动，展开了无人机基于飞行任务的敏捷性评估和仿真验证。对选取的3种飞行任务进行了详细的敏捷性评估方法描述，在通用的无人机敏捷性评估仿真环境中对加入非线性飞行控制律的某大机动无人机进行了基于3种飞行任务的敏捷性评估仿真验证，根据评估结果对控制律进行调参，为控制律设计提供指南和优化依据。     

挠性卫星姿态机动三段式轨迹规划与滚动跟踪控制

以新颖成像模式对挠性敏捷卫星姿态的快速机动控制为需求,本文针对金字塔构型控制力矩陀螺(CMG)群为执行机构的挠性卫星,提出基于三段式正弦角加速度的姿态路径规划方法及具有滚动优化思想的跟踪算法。在姿态路径规划方法设计中,融合谱分析及非线性优化方法,设计了兼顾卫星姿态机动快速性及抑制挠性附件振动性能的姿态轨迹;为实现对规划姿态轨迹的高精度跟踪,综合加权优化指标及奇异性、执行机构能力等约束,设计了金字塔构型CMG群框架角速度的非线性模型预测(NMPC)跟踪控制律。在转动惯量存在测量误差及空间干扰情况下,多种姿态机动仿真表明,本文提出的控制方法是有效的,且表现出较强的鲁棒性。     

Autonomous Maneuver Decisions via Transfer Learning Pigeon-Inspired Optimization for UCAVs in Dogfight Engagements

This paper proposes an autonomous maneuver decision method using transfer learning pigeon-inspired optimization (TLPIO) for unmanned combat aerial vehicles (UCAVs) in dogfight engagements. Firstly, a nonlinear F-16 aircraft model and automatic control system are constructed by a MATLAB/Simulink platform. Secondly, a 3-degrees-of-freedom (3-DOF) aircraft model is used as a maneuvering command generator, and the expanded elemental maneuver library is designed, so that the aircraft state reachable set can be obtained. Then, the game matrix is composed with the air combat situation evaluation function calculated according to the angle and range threats. Finally, a key point is that the objective function to be optimized is designed using the game mixed strategy, and the optimal mixed strategy is obtained by TLPIO. Significantly, the proposed TLPIO does not initialize the population randomly, but adopts the transfer learning method based on Kullback-Leibler (KL) divergence to initialize the population, which improves the search accuracy of the optimization algorithm. Besides, the convergence and time complexity of TLPIO are discussed. Comparison analysis with other classical optimization algorithms highlights the advantage of TLPIO. In the simulation of air combat, three initial scenarios are set, namely, opposite, offensive and defensive conditions. The effectiveness performance of the proposed autonomous maneuver decision method is verified by simulation results.      

机动目标角闪烁对制导精度影响仿真研究

角闪烁是现代防空制导武器的主要误差源.针对隐身飞机目标动态角闪烁外场测量难度大、耗时长、精度低的问题,提出了一种基于Simulink仿真回路的目标角闪烁特性的动态仿真方法.借助商业电磁仿真软件FEKO获取目标动态散射特性,并按实际问题的物理意义构建寻的制导系统模型.最后,通过仿真获得目标俯冲机动条件下角闪烁对制导精度的影响.仿真结果表明:该方法能获得目标动态电场散射信息,进而计算出目标的角闪烁信息.目标采用超低空大角度俯冲机动会有效改善突防效果,增大制导误差.该研究为防空制导武器抗诱偏、降低脱靶量等方面提供了理论分析和实验依据.     

基于自适应滑模方法的航天器位置与姿态控制

为了解决存在参数不确定和外干扰的航天器位置与姿态控制问题,提出一种自适应滑模控制方法.该方法用于控制航天器的位置和姿态,确保航天器执行位置与大角度机动,完成捕获和移除大空间目标的任务.提出的控制算法无需不确定的界,比传统的滑模方法容易实现.Lapunov分析表明,设计的控制器保证了位置与姿态的渐近跟踪.最后,将该方法用于航天器的位置与姿态控制,仿真结果验证了方法的有效性.