新型塑合木制备研究

本文介绍了塑合木的新工艺,配方、产品性能和应用前景。利用本文研究的加热-催化法制备塑合木,其成本可大幅度降低．     

盘─鼓结构体─壳过渡元的“虚假应力”现象及改进方法

分析了体—壳过渡元中产生“虚假应力”现象的根本原因，给出了两种改进方法。方案一是在采用体元应力应变模型的基础上提出了一种单元内位移、应变及应力的直接修改方法；方案二是将采用壳体应变应力状态的三维体—壳过渡元推广到轴对称，给出了具体公式。通过几个算例将上述两种方法与改进前方法进行了比较，结果表明本文提出的两种方案均大大改善了轴对称问题体壳过渡元的“虚假应力”现象，相比之下，前者公式简单，更易于实现。     

基于TMS320C5402的CVSD编解码实时实现

本文讨论了连续可变斜率增量调制（CVSD）语音编解码算法的原理及其特点,并在MATLAB中进行了仿真,结果表明,选择合适的量阶初值,量阶能够自动地随输入信号平均斜率的大小而连续变化,解码后的输出能够很好的逼近原始输入语音信号。最后,讨论了连续可变斜率增量调制算法（CVSD）在TMS320C5402实时实现过程中软、硬件的设计。     

考虑相关性的同级叶片系统强度可靠度分析方法

提出了考虑相关性的同级叶片系统强度可靠度分析方法.该方法包括同级叶片强度随机变量相关系数的数值模拟方法、同级叶片强度临界状态函数之间相关系数的确定方法.并给出考虑材料相关性的同级叶片系统可靠度计算二阶窄界限公式.讨论了考虑失效相关的同级叶片系统强度可靠度不同计算方法.最后通过算例表明所提出方法的有效性.      

温度传感器调理电路的桥路分析与灵敏度研究

在载人航天器的研制过程中,高精度温度测量电路的研究对于航天产品正常工作具有重要意义。温度传感器所反映的温度水平的准确程度对航天系统的温度控制起着至关重要的作用,通常采用高灵敏度、高可靠的热敏电阻作温度传感器对航天器舱内环境温度和航天员体温进行监测。文章从理论出发对温度传感器调理电路的惠斯登电桥和热敏电阻的灵敏度进行分析,探讨了电桥的桥臂电阻和热敏电阻参数对测量灵敏度的影响,得出了满足载人航天要求的高精度温度测量方法。     

适用于多星并行测试的应答机设计方法与验证*

为了提高星座的测试效率、降低测试成本,提出一种适合多星并行测试的应答机设计方法,通过地面测试设备和星上测控应答机复用星上的遥控RS422接口、遥测RS422接口的方式,突破了多星并行测试的瓶颈。新方法已经成功应用于某卫星星座的并行测试,降低了测试成本、提高了测试效率、缩短了星座的测试周期。     

Simulation of the land surface temperature from moon-based Earth observations

The land surface temperature (LST) is a key parameter for the Earth’s energy balance. As a natural satellite of the Earth, the orbital of the moon differs from that of current Earth observation satellites. It is a new way to measure the land surface temperature from the moon and has many advantages compared with artificial satellites. In this paper, we present a new method for simulating the LST measured by moon-based Earth observations. Firstly, a modified land-surface diurnal temperature cycle (DTC) method is applied to obtain the global LST at the same coordinated universal time (UTC) using the Moderate Resolution Imaging Spectroradiometer (MODIS) LST products. The lunar elevation angles calculated using the ephemeris data (DE405) from the Jet Propulsion Laboratory (JPL) were then applied to simulate the Earth coverage observed from the moon. At the same time, the modified DTC model was validated using in situ data, MODIS LST products, and the FengYun-2F (FY-2F) LST, respectively. The results show that the fitting accuracy (root-mean-square error, RMSE) of the modified DTC model is not greater than 0.72?°C for eight in situ stations with different land cover types, and the maximum fitting RMSE of the modified model is smaller than that of current DTC models. By the comparison of the simulated LST with MODIS and FY-2F LST products, the errors of the results were feasible and accredited, and the simulated global LST has a reasonable spatiotemporal distribution and change trend. The simulated LST data can therefore be used as base datasets to simulate the thermal infrared imagery from moon-based Earth observations in future research.     

Optimal spacecraft rendezvous using the combination of aerodynamic force and Lorentz force

This paper presents a propellantless spacecraft rendezvous method by using the optimal combination of aerodynamic force and Lorentz force. Aerodynamic force is provided by the rotations of the plates attached to the spacecraft, and Lorentz force is achieved by modulating spacecraft's electrostatic charge. Considering the limitation of the charging level of the spacecraft and physical constraints of the plates system, an optimal open-loop rendezvous trajectory is designed, which aims to minimize the energy consumed to actuate the hybrid system. The rotation rates of the plates and the electrostatic charge are constrained in the optimization problem, which is solved via the Gauss pseudospectral method. To track the open-loop trajectory in the presence of external perturbations, a novel adaptive nonsingular terminal sliding mode controller is designed. The stability of the closed-loop system is proved by the Lyapunov-based method. Several numerical examples are conducted to verify the validity of both the open-loop and closed-loop control strategy.     

基于分布式自适应的多智能体容错一致性控制

针对"领航者-跟随者"的多智能体编队，由于领航者系统出现故障引起编队通讯中断而不能完成任务的问题，提出了一种基于一致性理论的分布式自适应控制方法，用于解决该问题。首先，以一个位于顶点的智能体作为领航者，其余3个位于同一条线上的智能体作为跟随者，由此所构成的三角形编队作为被控对象。其中，领航者速度方向作为编队的前行方向，跟随者位于领航者之后。其次，基于图论，对智能体局部信息参数进行分布式自适应更新，并设计分布式自适应控制律，用于弥补多智能体编队中领航者故障所造成的影响。同时，根据相邻智能体的局部信息，设计整体分布式自适应容错控制律，进一步通过构建合理的Lyapunov函数，证明所设计控制器的稳定性，以及"领航者-跟随者"之间相对横向以及相对纵向的距离误差均收敛于固定常数。最后，仿真验证表明：所提出的自适应控制方法具有良好的鲁棒性，这也为工程实践提供了理论依据。