大长径比导弹两自由度H∞减振跟踪控制器设计

针对大长径比导弹弹体振动与控制系统耦合产生的气动伺服弹性问题,提出两自由度H∞减振跟踪控制算法.在导弹俯仰通道弹性振动和刚体运动耦合模型的基础上进行控制器设计,把传感器在线输出测量值和参考弹道目标值作为控制器的2个输入,把前两阶弹性模态、跟踪误差和控制量引入到目标函数中,将两自由度控制器的设计问题转化到标准H∞优化框架.仿真结果表明,该方法在实现姿态跟踪的同时,对弹体振动有明显的抑制作用.     

细长体飞行器主动弹性抑制控制律设计及分析

针对未来采用大长细比、轻质新型复合材料的飞行器结构模态频率进一步降低、气动伺服弹性问题更加严峻的问题,采用智能变结构控制方法,将广义坐标作为反馈量,并针对静不稳定弹性飞行器设计了纵向姿态控制器;然后,基于李亚普诺夫稳定性理论分析了闭环系统的稳定性;最后,通过定点仿真检验了所设计控制器的时域响应特性和对扰动的鲁棒性。仿真结果表明,当弹性模态频率与刚体频率接近时,与传统的基于陷波滤波器的设计方法相比,增加弹性反馈变量的智能变结构控制方法是一种解决气动伺服弹性问题的有效途径。     

基于广义最小二乘法的空空导弹幅值滤波器设计方法

空空导弹在飞行的过程中,由于弹体弹性模态时变特性而引起幅值滤波器参数无法预先精确设置,导致滤波器滤波效果减弱。针对这一问题,本文首先建立了空空导弹的纵向刚体和弹性体混合数学模型,在此基础上,借鉴最小二乘法在线估计弹性模态参数的方法,提出了广义最小二乘法在线估计的改进措施,解决了弹体弹性模态求解过程中由于扰动等因素带来的有色噪声干扰问题。同时,在控制系统结构中引入振荡模态角频率反馈模块,实时修正滤波器中心频率,提高了滤波效果。通过六自由度仿真算例验证该方法的可行性。     

利用频域约束条件设计鲁棒控制器

本文介绍一种设计控制器的方法,这种控制器能够提高对缩简弹性模态的鲁棒性。这种方法包含有受频域约束的二次性能指标最小化的问题。频域判据的选择要能有效地衰减整个动力学系统的高频响应,而又要能够保持闭环系统总的性能。所得到的约束条件关系构成函数最小化的结构,并且利用参数最优化的方法求解。     

某捷联陀螺环境应力筛选装置结构优化

为降低某捷联陀螺环境应力筛选装置的随机振动响应,对装置的结构进行优化。首先进行了模型的理论简化并建立了数学模型,运用模态分析理论和有限元软件对装置结构进行了振型和频率的理论分析和仿真计算。结果表明,该装置结构在1000 Hz频率附近存在z方向的振型,与陀螺仪谐振频率接近。根据理论分析的结果中相关参数对频率的影响关系,优化了系统结构,提高了系统在该方向的谐振频率,降低随机振动响应幅值。仿真计算和随机振动响应测试结果表明,改进后的结构谐振频率提高到预期效果,振动响应降低,满足了系统的使用要求。     

弹性导弹侧向动态特性分析

为研究大展弦比巡航导弹在弹性振动时的侧向动态特性,采用NASTRAN软件计算了结构的固有模态,分析了弹性振动时的附加非定常气动力,建立了刚体扰动运动方程组,将弹性振动引起的附加非定常气动力作为干扰输入项代入扰动运动方程组,得到了弹性振动下的动态响应.结果表明,大展弦比巡航导弹的弹性振动主要为翼面的振动;在满足气动与结构稳定的前提下,弹性振动引起的侧滑角偏量非常微小;倾斜角偏量比较大,各姿态角都在做微幅高频振荡,对弹上惯性器件的测量将造成不利影响,必须采取滤波等方式将此不利因素消除.     

高超声速飞行器伺服弹性与静不稳定控制方法

针对高超声速飞行器纵向静不稳定和低频结构模态下的气动伺服弹性控制问题,设计了一种双回路结构的鲁棒控制器。内环基于线性变参数(LPV)理论设计变增益控制器,将弹性模型表示成具有仿射参数依赖结构的LPV模型,采用线性矩阵不等式(LMI)求解变增益控制器以保证在任何载荷条件飞行器都具有足够的结构阻尼;外环设计鲁棒控制器实现飞行器对攻角指令的准确跟踪。仿真结果表明,该方法能够主动对结构模态进行阻尼从而达到抑制伺服弹性的效果,同时实现了飞行器纵向短周期模态稳定和对控制指令的高精度跟踪。     

舵机传动机构动力学建模与分析

针对舵机系统试验模态值偏低及一致性较差的问题,运用有限元与多刚体系统动力学方法,建立舵机传动机构集中质量-弹簧多刚体动力学模型,研究系统模态、动力学响应等主要动力学特性,发现了对动力学特性影响突出的薄弱设计环节,加以改进,满足了实际工程需要。     

弹性体导弹主动减振组合控制器设计

将导弹弹体弹性变形引起的附加气动力引入导弹刚体运动方程和弹性振动方程,推导出弹性体导弹数学模型,在此基础上引入主动作动力,建立起适合进行主动减振设计的弹性体导弹状态空间模型.针对解耦的刚性子系统设计H∞控制器模拟刚体导弹控制器,针对弹性子系统设计LQR控制器,再考虑耦合项对弹性子系统进行控制器设计,得到主动减振组合控制器.仿真结果验证了所设计的组合控制器在保证弹体运动姿态控制的同时具有较好的减振效果.     

弹性变形对大长细比导弹纵向稳定性的影响

综合考虑飞行动力学和气动弹性力学的相互影响,基于结构弹性模态和刚体飞行模态,耦合求解非定常气动力和结构动力学模型,研究大长细比导弹受弹性变形影响时的纵向稳定性.研究发现,大长细比导弹的弹性特征明显,结构弹性变形和刚体运动之间的相互影响不容忽视,分析大长细比导弹稳定性时需要将结构弹性变形与刚体运动统一起来进行研究.考虑刚体俯仰模态后,导弹的稳定性发生显著变化,系统由稳定变为不稳定,在较低动压下系统失稳,主要表现为俯仰模态的静失稳发散.来流动压和结构刚度会影响大长细比导弹的纵向稳定性.     

Nitrosation and Nitration of Tetraacetyldibenzylhexaazaisowurtzitane

Tetraacetyldibenzylhitane (TADBIW) was subjected to debenzylation by nitrosating with inorganic materials available commercially to synthesize tetraacetyldinitrosohexaazaisowurtzitane (TADNSIW). TADNSIW was purified, and its structure was determined by FTIR, 1H NMR, MS and element analysis. The debenzylation reaction of TADBIW gave quantitative benzaldehyde as a by-product. This indicates that the reaction produces an imine cation as an intermediate. Hexanitrohexaazaisowurtzitane (HNIW) was prepared from unpurified TADNSIW with the yield over 96.0 % and the purity more than 98.0 %. And the mechanism of the reaction from TADNSIW to HNIW is proposed to be oxidation of nitroso and nitration of acetyl on the molecule of TADNSIW, This reaction system involved is simple, and the reaction can complete within a short time and under mild conditions. The product can be easily to separate and the waste disposed readily.     

A Robust Algorithm for Watermarking 2D Vector Maps with Low Shape-Distortions

The technique of watermarking has been introduced into 2D vector maps for many potential applications such as protecting the copyright of important GIS （geographical information system） data and tracing the data source of military maps. In most previous works, although the validity of the map data could be preserved during the embedding procedure, the shape-distortions of the map elements are usually neglected which would tend to degrade the invisibility of the watermarking schemes. A shape-preserving algorithm for watermarking 2D vector maps is presented in this paper. A 1D distance sequence extracted from the original map is adopted as the cover data instead of 2D coordinates. A watermark bit is represented by changing the distributions of the cover data. The embedding procedure induces lower shape-distortions than in former works. Experimental results indicate better invisibility of the proposed scheme, as well as its robustness to certain attacks such as map simplification, interpolation, additive noise and most geometric transforms.     

Open Rule-setting System Applied to Conceptual Design of Engines

Open rule-setting method advanced in this paper concentrates on providing designers of engines with a convenient way to express their design innovations and develop the expected prototypes in the early CAD stage, and constitute effective models for the following analysis process of CAE and CAPP. The problems arisen in the process of conceptual design with the traditional experience-based development method are analyzed. Based on those analyses, open rule-setting method is presented and some associated technical problems are discussed. The functional framework of open rule-setting system was built as software engineering methods. The speciality of the engine product as a kind of complex product and the requirement of the engine product based on its structural particularity to rule-setting system are considered carefully. A demonstration is supplied to illustrate how the open rule-setting method enhances the efficiency and quality of the engine conceptual design.     

Research on Linux Network Device Driver

By analyzing the working principle of Linux network device driver, discussing the Linux network driver structure and its key technologies, the general network driver structure and its design methodologies in Linux system are summarized. Through modifying the network device driver of Linux device driver 3rd version snull, c and improving the COW technology, the Zero-Copy technology in Linux （kernel version 2.6.11 ） is implemented. In the end, the success test tells us that the thorough analysis of network device driver is the foundation of many applications, and it also provides a certain improvement to a lot of real applications, even to military application development.     

Improvement and Experiment of the Reamer in Vibra Cutter Against Wave Edge of Titanium Sheet Alloy Parts

By analyzing the influencing factors of part quality making of sheet alloy of titanium by vibra cutter, the shape of upper reamer is set as cylinder and wedge-shaped form, and the lower reamer as plain and hemicycle form, and its main structural parameters are defined as well. Then it is validated further that such improved vibra cutter reamer can be used to process curve-edged parts of titanium alloy sheet. The experimental result shows that the titanium alloy sheet parts processed by above equipment have no sharpen angles for convex parts and evident crevasse of concave-edged part. In summary, such improvement can eliminate the free-waved edge and improve the manufacture quality of titanium alloy sheet parts greatly.     

Experimental Study on the Small Flyer Initiating Behavior of Fine-grained Explosives

The initiating behavior of fine-grained explosives by small flyer is studied. The diameter of small flyer in this device is 1 ram. The test results indicate that the granularity of explosives has great effect on its flyer initiating sensitivity.The flyer initiating sensitivity of the fine-grained explosives is higher and the critical initiating energy is lower than that of common explosives. For common explosive, the flyer initiating sensitivity increases as the density is reduced. But for the fine-grained explosive, the test results are exactly opposite.     

Algorithm for Multi-laser-target Tracking Based on Clustering Fusion

Multi-laser-target tracking is an important subject in the field of signal processing of laser warners. A clustering method is applied to the measurement of laser warner, and the space-time fusion for measurements in the same cluster is accomplished. Real-time tracking of multi-laser-target and real-time picking of multi-laser-signal are introduced using data fusion of the measurements. A prototype device of the algorithm is built up. The results of experiments show that the algorithm is very effective.     

Influence of Installing Error on the Surface Shape Precision of the Axial Symmetry Aspheric Workpiece in Lapping

A method to calculate the surface shape error, which is caused by the installing error between the workpiece and the lapping tool in the process of form lapping, is proposed. The mathematical model which the installing translation error influences on the workpiece surface shape error is established. The changing rule of the error is simulated through the calculating example of the paraboloid workpiece. The results indicate that the surface shape error of the workpiece is increasing with the increase of the installing translation error, it is also increasing gradually along the center point of the curve surface to the edge, and the influence is severer to the curve surface with great curvature than that of the small curvature when the translation error is the same.     

Experimental Research on Output Performances of Giant Magnetostrictive Actuator

The paper introduces the performances of magnetostrictive actuators and its applications, discusses the design methods for the structure and internal magnetic circuit of a giant magnetostrictive actuator, and makes tests on the output displacement and force characteristics for an actuator using homemade magnetostrictive material. The experimental result shows that the actuator has satisfactory output precisions and ranges in transient and stable states, and can be used in lowfrequency vibration control system of precise equipment.     

Robust Graded Sliding Mode Tracking Control for Low Speed Spinning Ballistic Missiles

The nonlinear dynamic model of spinning ballistic missiles is established during the first boosting phase of the missile. Based on the conventional backstepping sliding mode control and the assumption of a two time-scale separation of missile dynamics, a graded sliding mode controller is designed with two sub-sliding surfaces which have invariability to external disturbances and parameter perturbations, and a matrix which comprises three first order low pass filters is introduced to prevent ＂explosion of terms＂. Owing to the upper bounds of the uncertainties are difficult to obtain in advance, adaptive laws are introduced to estimate the values of the uncertainties in real-time. Eventually, the numerical simulation results given to show the proposed controller can ensure the steady flight of missiles.