非线性不确定系统的鲁棒H∞控制

考虑一类带有界结构不确定因素的非线性不确定系统的鲁棒Ｈ∞控制问题。给出了实际鲁棒Ｈ∞控制的定义以及系统实际鲁棒Ｈ∞控制可解的充分必要条件。结果表明实际鲁棒Ｈ∞控制问题的可解性与一个Ｈａｍｉｌｔｏｎ－Ｊａｃｏｂｉ－Ｉｓａａｃｓ微分不等式的正解存在性是等价的。     

航天电子产品整机的装联布线

文章介绍了航天电子产品整机装联布线的原则、注意要点、方法、顺序及常见问题的处理。     

计算机压电测压系统在弹道压力测量中的应用

介绍了计算机压电测压系统的组成、压电测压传感器的工作原理以及压电测压系统等效电路和标定     

Modularity and Spacecraft Cost

From computers to aeronautics, many industries have achieved great cost savings through the use of modular engineering approaches. In standardizing interfaces between elements and by reusing functional units, projects can achieve direct reductions in required development labor and secondary savings from enhanced reliability via improved process control from manufacturing identical units. Issues involved in the extension of modular design to the space industry are discussed. A cost model is developed to resolve some of the conflicting advantages and disadvantages between modular and customized designs. Key regimes are identified that represent the best opportunities for applying modular concepts.     

基于模型的数字式电液作动器智能控制方法

本文针对数字式电液作动器的位置控制展开研究,提出了一种基于模型的算法,能够实时的对数字式电液作动器系统的状态进行预测,根据预测的状态完成位置控制。在阀脉冲宽度调制(Pulse Width Modulation, PWM)方法和脉冲数量调制(Pulse Number Modulation, PNM)方法的基础上,改进了数字阀系统的控制方法。建立了完整的数字式电液作动器系统的模型,通过软件联合仿真得到作动器的控制结果。最终结果表明：采用基于模型的算法,能够使得作动器的追踪精度达到0.5mm。与传统方法相比,此方法逻辑简单,可行性强,控制效果较好。     

高速冲击下块体金属玻璃动力学响应的实验研究

块体金属玻璃具有极高的力学强度,存在潜在的军事应用价值,实现其应用的关键在于认识材料在高应变率下的动力学行为特性。为此,利用飞片驱动速度可达3．5km／s的电炮加载装置,对一种新制备的锆基块体金属玻璃的动力学响应进行了实验研究。实验中,基于高精度DPS激光干涉仪测得的样品／窗口界面粒子速度波剖面,获得了新材料在应变率约为10^5／s下的冲击响应特性参数。在加载压力15～25GPa范围下,确定的Hugoniot弹性极限约为2．4GPa,线性拟合得到的冲击Hugoniot关系为Ds=（4．4±0．1）＋（0．58±0．08）up。     

Analytic estimation and numerical modeling of actively cooled thermal protection systems with nickel alloys

Actively cooled thermal protection system has great influence on the engine of a hypersonic vehicle, and it is significant to obtain the thermal and stress distribution in the system. So an analytic estimation and numerical modeling are performed in this paper to investigate the behavior of an actively cooled thermal protection system. The analytic estimation is based on the electric analogy method and finite element analysis（FEA） is applied to the numerical simulation. Temperature and stress distributions are obtained for the actively cooled channel walls with three kinds of nickel alloys with or with no thermal barrier coating（TBC）. The temperature of the channel wall with coating has no obvious difference from the one with no coating, but the stress with coating on the channel wall is much smaller than that with no coating. Inconel X-750 has the best characteristics among the three Ni-based materials due to its higher thermal conductivity, lower elasticity module and greater allowable stress. Analytic estimation and numerical modeling results are compared with each other and a reasonable agreement is obtained.     

Sensor selection of helicopter transmission systems based on physical model and sensitivity analysis

In the helicopter transmission systems, it is important to monitor and track the tooth damage evolution using lots of sensors and detection methods. This paper develops a novel approach for sensor selection based on physical model and sensitivity analysis. Firstly, a physical model of tooth damage and mesh stiffness is built. Secondly, some effective condition indicators(CIs) are presented, and the optimal CIs set is selected by comparing their test statistics according to Mann–Kendall test. Afterwards, the selected CIs are used to generate a health indicator(HI)through sen slop estimator. Then, the sensors are selected according to the monotonic relevance and sensitivity to the damage levels. Finally, the proposed method is verified by the simulation and experimental data. The results show that the approach can provide a guide for health monitoring of helicopter transmission systems, and it is effective to reduce the test cost and improve the system's reliability.     

Finite-time sliding mode attitude control for a reentry vehicle with blended aerodynamic surfaces and a reaction control system

This paper proposes a finite-time robust flight controller, targeting for a reentry vehicle with blended aerodynamic surfaces and a reaction control system(RCS). Firstly, a novel finite-time attitude controller is pointed out with the introduction of a nonsingular finite-time sliding mode manifold. The attitude tracking errors are mathematically proved to converge to zero within finite time which can be estimated. In order to improve the performance, a second-order finite-time sliding mode controller is further developed to effectively alleviate chattering without any deterioration of robustness and accuracy. Moreover, an optimization control allocation algorithm, using linear programming and a pulse-width pulse-frequency(PWPF) modulator, is designed to allocate torque commands for all the aerodynamic surface deflections and on–off switching-states of RCS thrusters.Simulations are provided for the reentry vehicle considering uncertain parameters and external disturbances for practical purposes, and the results demonstrate the effectiveness and robustness of the attitude control system.     

新型针式高压隔离阀的设计和试验

空间推进任务有时需要气体推进剂在高压贮箱内密闭长达数年,隔离阀作为隔离贮箱内高压气体推进剂的装置,不仅要求在数年后可正常启动,而且在高压条件下必须严格控制推进剂的泄漏量。因此,提出了一种新型高压气体隔离阀,其采用中空启动针穿破隔离装置的启动方式以减小金属碎屑对气体微通道的影响。对该隔离阀进行了开启验证试验,并以开启隔离阀前后通过启动针的气体流量之比作为一个重要参数,分析了金属碎屑对气体微通道的影响。结果表明:开启隔离阀的功率约为5.6 W,满足微小卫星对低功率的严格要求;同时气体流量之比约为95%,可认为金属碎屑对气体微通道的影响比较小。