月球车全局路径规划中的A＊算法改进

考虑月球车全局路径规划的应用要求,针对传统A＊算法搜索速度慢和返回路径不够优化的缺点,对算法流程进行改进,减少其时间和空间复杂度,提高其搜索速度,并对返回路径进行优化,有效地缩短了路径。对于存在凹形障碍的地图,采用后退一尝试的方法解决规划失败的问题,并在一次搜索的基础上使用二次搜索策略来实现规划路径的优化,使之绕过凹形障碍趋向目标,从而达到输出最短路径的目的。     

基于Dixon结式的一种9杆巴氏桁架位置分析

将Dixon结式运用到基本运动链的位置分析中,完成了一种对称型非平面的9杆巴氏桁架的位置分析的研究,首次给出了这种巴氏桁架解析解的个数.结合矢量法和复数法建立了4个几何约束方程式,使用Dixon结式构造22×22的Dixon矩阵,对两列提取公因式后展开矩阵的行列式得到一元64次多项式方程,回代过程中去掉6组增根后得到58组解.为了对结果进行验证,使用同伦连续法对同一个数字算例进行计算,两种方法得到结果一致,说明这种巴氏桁架的装配构形数目是58.      

立式偏心仪

阐述了立式偏心仪的结构原理、重心位置的确定方法和误差分析。     

HVA—10A型维氏硬度计压痕位置的调整

重点介绍压痕在视场内或不在视场内的调整方法以及调整过程中对同轴度的影响。     

A memetic algorithm for path planning of curvature-constrained UAVs performing surveillance of multiple ground targets

The problem of generating optimal paths for curvature-constrained unmanned aerial vehicles （UAVs） performing surveillance of multiple ground targets is addressed in this paper. UAVs are modeled as Dubins vehicles so that the constraints of UAVs＇ minimal turning radius can be taken into account. In view of the effective surveillance range of the sensors equipped on UAVs, the problem is formulated as a Dubins traveling salesman problem with neighborhood （DTSPN）. Considering its prohibitively high computational complexity, the Dubins paths in the sense of terminal heading relaxation are introduced to simplify the calculation of the Dubins distance, and a boundary-based encoding scheme is proposed to determine the visiting point of every target neighborhood. Then, an evolutionary algorithm is used to derive the optimal Dubins tour. To further enhance the quality of the solutions, a local search strategy based on approximate gradient is employed to improve the visiting points of target neighborhoods. Finally, by a minor modification to the individual encoding, the algorithm is easily extended to deal with other two more sophisticated DTSPN variants （multi-UAV scenario and multiple groups of targets scenario）. The performance of the algorithm is demonstrated through comparative experiments with other two state-of-the-art DTSPN algorithms identified in literature. Numerical simulations exhibit that the algorithm proposed in this paper can find high-quality solutions to the DTSPN with lower computational cost and produce significantly improved performance over the other algorithms.     

多弹编队飞行控制技术研究

针对未来复杂战场环境下反舰导弹编队协同攻击的技术需求,提出了一种多弹编队飞行控制的技术方案。采用基于分层递阶控制思想的多智能体系统结构,把多枚功能相同或者不同的导弹按照一定的原则组合成弹群,弹群中各导弹之间进行编队飞行、协同搜索、信息融合和协同攻击等方面的作战配合,实现对单个目标或多个目标的精确打击。该方案可以实现多发导弹的编队飞行控制,能够提高导弹编队的体系对抗能力。     

基于自抗扰控制技术的无人直升机位置控制律设计

针对无人直升机抗风性能不足的问题,将自抗扰控制方法应用于无人直升机位置控制律,该位置控制律在常规内外回路控制架构的基础上,外回路采用非线性反馈,利用扩张状态观测器（ESO）进行动态扰动补偿。此文详细阐述了设计方法和工程应用问题。半物理仿真结果表明,该控制方案具有较强的抗扰动性,位置控制精度得到显著提升。     

典型水文环境下航空声呐浮标双基地作用范围

航空声呐浮标双基地探测是应对水下目标声隐身能力持续提高的有效技术途径之一。分析了航空声呐浮标的指标,给出了双基地声呐配置,采用双基地声呐方程为依据,利用数值仿真的方法计算了 3种典型海洋环境条件下双基地声呐浮标探测范围,讨论了海洋环境对双基地声呐探测的影响,为航空声呐浮标双基地战术使用奠定技术基础。     

基于改进A*算法的UUV冰下避障航迹规划算法

针对冰下避障航迹规划问题,提出了一种基于改进A*算法的三维冰下避障航迹规划算法.不同于传统的A*航迹规划算法,该算法结合了人工势场航迹规划算法的思想,将水下地形碰撞约束、海冰碰撞约束以及UUV巡航高度约束重新编排.算法分析表明,该避障航迹规划算法能够有效增强UUV冰下避障能力与定深巡航高度控制能力.基于改进的A*冰下避障航迹规划算法,给出了上述约束的设计方法并进行了仿真验证.仿真结果表明,基于上述约束的航迹规划算法具有良好的避障能力、巡航高度控制能力以及航行距离控制能力.     

Effects of swirler position on flame response and combustion instabilities

This study is concerned with the experimental and theoretical investigation of the combustion instabilities in a premixed swirl combustor. It is focused on the effects of the swirl mixing distance on the intrinsic thermoacoustic mode. The swirler as an origin of the swirling flow is also the source of the flow disturbance, which has effects on the flame response. The location of the swirler is varied in the experiment to study the effect on combustion instabilities and flame transfer functions. ...