消防车供水遥控机

为了提高灭火速度，提高消防队的战斗力，本文提出了一种采用无线遥控技术直接由水枪手遥控水罐车油门来改变水枪射水压力的控制系统。     

订单式人才培养模式—高职高专办学新思路

本文简要论述了订单式人才培养模式的概念、特征,以及高职高专院校如何实施订单式人才培养。     

WEIGHTED COMPACT SCHEME FOR SHOCK CAPTURING

INTRODUCTIONRecently compact schemes have been widelyused in the simulation of complex flows,espe-cially in the directnumerical simulation of turbu-lent flows[1～ 2 ] . Standard finite differenceschemes have explicit forms and need to be atleastone pointwider than the desired approxima-tion order. It is also difficult to find suitable andstable boundary closure for high order schemes.Compared to the standard finite difference ap-proximations,the compact schemes can achievehigher order acc…     

一种基于叶盘结构几何失谐的降阶分析方法

叶片几何失谐严重影响叶盘结构的振动特性。为了准确且高效地对存在叶片几何失谐的叶盘结构进行振动分析,基于扇区建模方法,由动力学方程推导出降阶模型的表达式,利用该降阶方法对整个几何失谐叶盘结构分别进行模态分析和受迫响应分析,并与有限元方法进行固有频率和受迫响应结果的对比。结果表明:该降阶方法得到的结果与有限元方法得到的结果基本一致,验证了该方法的有效性和实用性。     

基于降阶ESO的微小型空地导弹改进LQR滚转控制

摘要： 由于投弹包络范围大及复杂多变的飞行环境,模型存在高度不确定性、外界阵风干扰以及弹体内部强扰动等,使得导弹滚转姿态具有一定控制难度;另一方面,对于弹翼展弦比小的轴对称微小型空地导弹来说,其结构特性的原因使得基于二回路经典控制论下的滚转姿态得到的控制品质较差,且鲁棒性及抗干扰能力弱.因此提出采用降阶ESO估计内外强干扰及不确定性等复合干扰并进行实时前馈补偿,在简化标称模型基础上利用最优控制思想即带有积分项的LQR稳定区间法来设计控制器,实现无静差稳定跟踪响应的复合控制方法,以此来提高弹体滚转姿态的动态特性、鲁棒性及抗干扰能力,并进一步证明其闭环稳定性,由仿真得出此复合控制方法优越性的结论.     

航材后续备件订货周期优化研究

针对目前部队航材备件订货周期方面存在的问题以及在理论研究方面存在的不足,以故障统计数据为基础,建立了一种新型的数学模型,解决了一定保障率的情况下使得订货周期更加合理,保障经费最小的问题.     

Fractional order adaptive robust formation control of multiple quad-rotor UAVs with parametric uncertainties and wind disturbances

In recent times, multiple Unmanned Aerial Vehicles (UAVs) are being widely utilized in several areas of applications such as agriculture, surveillance, disaster management, search and rescue operations. Degree of robustness of applied control schemes determines how accurate a swarm of UAVs accomplish group tasks. Formation and trajectory tracking controllers are required for the swarm of multiple UAVs. Factors like external environmental effects, parametric uncertainties and wind gusts make the controller design process as a challenging task. This article proposes fractional order formation and trajectory tacking controllers for multiple quad-rotors using Super Twisting Sliding Mode Control (STSMC) technique. To compensate the effects of the disturbances due to parametric uncertainties and wind gusts, Lyapunov function based adaptive controllers are formulated. Moreover, Lyapunov theorem is used to guarantee the stability of the proposed controllers. Three types of controllers, namely fixed gain STSMC and fractional order Adaptive Super Twisting Sliding Mode Control (ASTSMC) methods are tested for the swarm of UAVs by performing the numerical simulations in MATLAB/Simulink environment. From the presented results, it is verified that in presence of wind disturbances and parametric uncertainties, the proposed fractional order ASTSMC technique showed improved robustness as compared to the fixed gain STSMC and integer order ASTSMC.     

基于数值微分计算的SERF原子自旋惯性测量动态仿真

基于量子调控技术的SERF原子自旋惯性测量仪表与传统惯性测量仪表相比,具有精度高、无活动部件、对加速度不敏感等优点,被公认是下一代高精度惯性测量的发展方向。分析了SERF原子自旋惯性装置Bloch微分方程组模型下磁场、激光、角速度输入对碱金属电子极化率和惰性气体核子极化率的影响。针对实验条件下原子系综Bloch微分方程组难以解析求解的问题,基于可变阶次数值微分计算,建立了相应的Simulink模型对实验条件下的原子系综进行数值求解,并分析了极化率对光场、磁场、角速度输入的瞬态响应与稳态响应。仿真结果与理论计算结果相吻合,验证了Bloch方程数值求解的可行性与准确性。该方法可得到惯性测量系统的动态响应,可用于模拟复杂输入下的SERF原子自旋惯性测量系统的输出响应。     

航空公司欧美国际航线运营持续时间生存分析

航空公司航线进入后的运营可持续性直接影响其盈利水平。基于生存分析方法探究影响航线运营持续时间的因素，从成本和供给特征、航线和机场特征、市场结构特征、航司合作类型和时间异质性5个方面选取关键因素，以自由化程度较高的欧美跨大西洋市场为实证对象，研究年份为2003—2021共19年，采用Kaplan-Meier方法进行单因素分析，并构建威布尔参数生存模型分析影响因素与航线运营持续时间的定量关系。结果表明：（1）航司在欧美航线的平均运营持续时间为5年，持续运营超过10年的航线占比为16%;(2)距离、航司投入总运力、航线结构、端点机场类型和竞争程度、航司类型及所属区域和联盟对航司航线运营持续时间具有显著影响；（3）联盟和代码共享独立变量和交互变量均对航线生存产生显著影响，星空和天合联盟成员的航线运营持续时间更长，联盟成员在代码共享合作时承担不同承运人角色对航线退出风险影响存在显著差异。     

Performance analysis of the vectorized high order expansions method in the accurate landing problem of reusable boosters

This paper addresses the design of the terminal phase maneuver of the booster landing in the presence of initial deviations and uncertainties. The primary purpose of this study is to evaluate the effectiveness of the vectorized high order expansions method to extract commands and near-optimal trajectory, while the accurate satisfaction of the terminal conditions is of great importance. After reviewing high order expansions methods, the Vectorized High Order Expansions method is briefly discussed. Then, the solution for the booster landing problem is extracted up to the third order. To study the solution quality in the presence of uncertainties, mass, density, and gravity are assumed to be constant in extracting the 3rd order solution. The assumptions however are eliminated in the simulations, and the effectiveness of high order expansions solution is studied subjectively and numerically in the presence of initial deviations and uncertainties. After implementing simulations and considering different assumptions, it will be shown that the 3rd order solution holds a desirable quality in accurately satisfying final conditions in presence of uncertainties and initial deviations and provides far better results than the 1st order solution. Moreover, in this paper, a novel method is proposed for online updating, and the performance and effect of this modification are studied using simulations. Reviewing the results of the 3rd order solution combined with the online update strategy, it becomes clear that the implementation of the online update significantly reduces landing point errors and improves the performance of the high order method. Furthermore, the study compares the performance of this strategy with the well-known state-dependent Riccati equation method to better evaluate the effectiveness of the proposed approach.