地月低能转移轨道设计方法研究

研究地月低能转移轨道的设计方法。这种低能转移轨道利用了弱稳定边界理论，通过太阳的引力摄动，使得探测器能够不经过减速就被月球俘获。与经典的霍曼转移相比，低能转移轨道呵节省约140m／s的速度脉冲。由于设计是基于叫体问题模型进行的，问题具有很强的非线性特性，寻找满足约束条件的转移轨道变得非常困难。常用的两点边值问题的解法在这里都失效。本文在研究地月低能转移轨道特忡的基础上，对一般地月转移轨道搜索的变步长爬山法进行改进，用来设计地月低能转移轨道。仿真结果验证了该方法的有效性。     

阳极层推力器的研究现状与发展趋势

通过对阳极层推力器的工作原理、特点、羽流特性以及国内外阳极层推力器的研究现状与发展趋势的介绍和分析,指出了阳极层推力器是目前应用前景最好的电推进器之一,并且阳极层推力器正朝着更高功率和/或更高比冲的方向发展。随着空间技术的飞速发展,对高功率和/或高比冲的阳极层推力器的需求将越来越迫切,世界各国在这上面的投入也将越来越大。     

一个大挠度柱面弯曲板条的求解

本文应用付宝连的大挠度弯曲直梁的功的互等定理,求解一个柱面弯曲板条的挠曲面方程。     

基于工程应变的轴对称塑性大变形几何方程及其应用

从工程线应变和工程切应变的物理概念出发，根据“轴对称”和“大变形”的特点，推导出相应的几何方程，另导出大变形条件下的体积不变定律。与现有“有限变形”条件下的几何方程相比，不但更为精确，而且其表达形式在具体应用中更为简单。在一些典型的工艺问题中，将小变形条件下导出的几何方程应用于大变形情况也可能得出非常好的结果，不但运算简单方便，而且其精度还优于“有限变形”条件下的几何方程。     

大学生就业心理分析与应对

大学生就业问题已成为社会、高校、家庭的焦点问题。由于多方面原因,作为就业的主体—大学生在就业过程中会产生诸多心理问题,影响到自身的身心健康、也影响到自身就业的质量,甚至影响终身的成长。为了较好地解决这些问题,从大学生自身特点及生活、学习等方面进行剖析,使大学生能较客观、正确地认识就业中存在的心理现象与问题,并能够正确对待和处理。     

大学生思想政治教育问题与对策

目前大学生思想政治教育工作在思想观念、管理体制和队伍建设等层面都存在着一定的问题，与《中共中央关于进一步加强和改进大学生思想政治教育的意见》提出的新思想、新观念、新任务不相适应。因此，要保证大学生思想政治教育工作与时俱进，就必须更新观念，以德为本，树立开放的思想政治工作系统观；改革管理体制，切实还思想政治工作的首要地位；加强大学思想政治工作队伍专业化建设。     

Indirect Radau pseudospectral method for the receding horizon control problem

To solve the receding horizon control (RHC) problem in an online manner, a novel numerical method called the indirect Radau pseudospectral method (IRPM) is proposed in this paper. Based on calculus of variations and the first-order necessary optimality condition, the RHC problem for linear time-varying (LTV) system is transformed into the two-point boundary value problem (TPBVP). The Radau pseudospectral approximation is employed to discretize the TPBVP into well-posed linear algebraic equations. The resulting linear algebraic equations are solved via a matrix partitioning approach afterwards to obtain the optimal feedback control law. For the nonlinear system, the linearization method or the quasi linearization method is employed to approximate the RHC problem with successive linear approximations. Subsequently, each linear problem is solved via the similar method which is used to solve the RHC problem for LTV system. Simulation results of three examples show that the IRPM is of high accuracy and of high compu-tation efficiency to solve the RHC problem and the stability of closed-loop systems is guaranteed.     

利用温度测量结果反演三维热传导问题中热源项的算法研究

利用表面温度测量来反演热传导问题中的热源项是一类典型的热传导逆问题，在采用有限体积法对三维稳态热传导问题进行数值求解的基础上，将该热传导逆问题转化为优化问题，基于灵敏度分析建立了反演算法。采用该算法对一典型算例的计算结果表明：建立的算法是有效的，具有较好的抗噪性能。此外，对反演算法中计算收敛准则的选取进行了较深入的分析，结果表明，由于热传导逆问题的不适定性，优化过程中目标函数值越小并不意味着反演结果与真值更为接近，可以通过设定合适的收敛准则来模拟正则化项的作用，克服不适定性的影响。     

Multi-UAV reconnaissance task allocation for heterogeneous targets using an opposition-based genetic algorithm with double-chromosome encoding

This paper presents a novel multiple Unmanned Aerial Vehicles (UAVs) reconnaissance task allocation model for heterogeneous targets and an effective genetic algorithm to optimize UAVs’ task sequence. Heterogeneous targets are classified into point targets, line targets and area targets according to features of target geometry and sensor’s field of view. Each UAV is regarded as a Dubins vehicle to consider the kinematic constraints. And the objective of task allocation is to minimize the task execution time and UAVs’ total consumptions. Then, multi-UAV reconnaissance task allocation is formulated as an extended Multiple Dubins Travelling Salesmen Problem (MDTSP), where visit paths to the heterogeneous targets must meet specific constraints due to the targets’ feature. As a complex combinatorial optimization problem, the dimensions of MDTSP are further increased due to the heterogeneity of targets. To efficiently solve this computationally expensive problem, the Opposition-based Genetic Algorithm using Double-chromosomes Encoding and Multiple Mutation Operators (OGA-DEMMO) is developed to improve the population variety for enhancing the global exploration capability. The simulation results demonstrate that OGA-DEMMO outperforms the ordinary genetic algorithm, ant colony optimization and random search in terms of optimality of the allocation results, especially for large scale reconnaissance task allocation problems.