高精度光电伺服稳定平台控制技术

为提高光电稳定平台的伺服控制性能,对高精度光电伺服稳定平台控制技术进行探讨.针对伺服稳定平台控制策略,从2轴2框架伺服稳定平台、2轴4框架伺服稳定平台、复合轴高精度伺服稳定平台3个方面的结构、组成、控制策略进行对比分析,并对各种伺服稳定平台在PID控制策略对相同扰动条件下的隔离基座扰动能力进行仿真计算.仿真结果表明:采用复合轴高精度伺服稳定平台可大幅提高伺服稳定平台的抗扰动能力,为从事伺服稳定控制研究人员提供借鉴.     

基于滑模变结构控制的光电稳定平台控制策略研究

光电跟踪系统在载体运动的过程中会受到各种扰动,对系统的跟踪性能产生不利影响。滑模控制拥有较好的鲁棒性,在工程上容易实现,可考虑运用在这类系统中。使用摩擦反馈并将速度环滑模控制与跟踪环PID控制相结合,可得到一种应用于光电跟踪系统的滑模变结构控制策略,它提升了光电稳定平台的稳定精度,同时具有一定的鲁棒性,能使运行中的系统在外界环境变化时对变化的扰动有一定的适应能力。以二维伺服转台为被控对象设计了滑模控制器,进行仿真实验并与现有基于PID方法的控制方案对比。对比结果表明：在给定扰动下,基于滑模变结构控制策略的光电稳定平台将速度环稳定误差从72″/s降低到了12″/s,均方根从37.0″/s降低到了1.46″/s,提出的滑模变结构控制器对提升光电稳定平台的稳定精度有一定作用。     

机载光电稳定平台的强鲁棒性滑模变结构控制

为使机载光电稳定平台系统在复杂环境下仍具有强鲁棒性,建立光电稳定平台数学模型.以两轴四框架光电吊舱为研究对象,通过分析噪声干扰及本身结构参数的变化对光电稳定平台的影响,提出基于干扰观测器(disturbance observer,DOB)的滑模控制器设计方案.理论推导和仿真结果表明:滑模变结构控制(sliding mode variable structure control,SMVSC)对干扰力矩和摄动完全适应,对系统结构参数变化和外界扰动具有良好的鲁棒性;比无干扰观测器的控制系统,拥有更高的稳定精度和更快的动态响应,能增强光电稳定平台的抗扰动能力.     

四环式两轴稳定平台闭锁环控制系统设计与应用

四环式两轴稳定是一种高精度的陀螺稳定方案,广泛应用于机载光电吊舱等侦察监视设备中。本文提出一种四环式两轴稳定平台闭锁环失稳的解决方案。为分析此方法的性能,给出了精确分析模型。结果表明,与传统的控制方式相比,对稳定平台实施改进型的控制策略,能够在不改变稳定平台硬件的前提下,将系统的动态性能和静态性能提高10%。     

基于dSPACE平台的稳瞄控制系统建模方法研究

为提高机载光电稳瞄伺服控制系统分析与设计能力,提出一种基于dSPACE半实物仿真平台的稳瞄伺服控制系统速率稳定回路建模方法.该方法通过dSPACE对系统施加激励并采集信号,用最小二乘算法拟合系统频率特性,利用MATLAB辨识工具箱辨识出系统传递函数.对某机载光电稳瞄伺服控制系统,利用本方法获取对象模型并进行控制器设计,...     

极坐标两轴稳定平台的模型与分析

稳定平台系统可以提供导弹与目标之间的相对位置关系,为导弹姿态和弹道的修正提供依据,在导弹系统中具有十分重要作用.本文通过坐标变换将弹体运动分别在外框坐标系和内框坐标系中描述,得到两轴框架的运动学关系,基于刚体定点运动欧拉动力学原理.建立极坐标速率陀螺式两轴稳定平台的动力学模型,针对两轴框架的驱动电机,进一步建立包含电机电流环和力矩环的机电模型.最后结合实际数据,利用所建的机电模型对弹体运动耦合产生的扰动进行了仿真分析,仿真表明:弹体运动对视线角速度具有扰动作用,需要进行速度回路控制进行解耦补偿.所得模型和分析结果为极坐标稳定平台的进一步研究提供了理论基础.     

自由空间激光通信平台振动模拟实验系统研究

为了对自由空间激光通信中的高精度、复合轴捕获、跟踪和瞄准(APT)系统的关键技术进行验证,需要对平台的振动或扰动进行半实物仿真。在对通信平台振动功率谱进行分析的基础上,基于MATLAB/Simulink建立了平台振动半实物模拟实验系统,通过半实物仿真得出平台的振动时域信号及其振动功率谱。通过CCD闭环检测,证明了平台振动模拟结果真实有效。将模拟产生的振动信号作为自由空间激光通信复合轴APT实验系统的激励,实现了在模拟振动和运动条件下对复合轴APT跟踪系统的实验室验证。     

基于扰动观测器的机载光电稳定平台自适应指数时变滑模控制

针对考虑载机干扰、摩擦力矩和参数不确定性等扰动因素影响的机载光电稳定平台高精度控制问题,提出了一种基于非线性扰动观测器的自适应指数时变滑模控制方法。该方法利用非线性扰动观测器观测系统的聚合不确定性,用来抵消外界扰动和参数不确定性对系统的干扰。在此基础上,设计自适应指数时变滑模控制器,实现了光电稳定平台伺服系统在残余聚合扰动影响下的期望角位置转动的全局鲁棒控制,该方法不需要确定聚合不确定性的上界信息,同时避免了普通自适应滑模的切换增益过度自适应问题,最终通过李雅普诺夫稳定性定理证明了闭环系统的全局渐近稳定性,系统角位置最终渐近收敛到期望角位置。数值仿真和样机测试结果表明,在外界扰动和参数不确定性的影响下,该方法能够实现系统的高精度角位置控制。     

四框架稳定跟踪平台原理样机设计与实现

为稳定并改造跟踪平台的性能,针对现有文献侧重于理论研究的问题,构建机载四框架稳定跟踪平台的原理样机。以某型号机载四框架稳定跟踪平台项目为研究对象,介绍平台的机械系统和电气控制系统,设计伺服控制回路和自动跟踪控制回路,并给出相应的控制策略。试验结果表明:该设计理论分析正确,控制系统合理。     

航空吊舱稳定平台结构设计

首先指出稳定平台在光电吊舱系统中的重要地位,然后对两轴两框架系统和两轴四框架系统两种典型稳定平台的结构原理、气动外形和驱动方式等进行了介绍,确定了设计方法,并对两种稳定平台的性能进行了对比,指出两轴四框架系统是稳定平台的发展方向。     

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.