Control of downrange and crossrange motion of a descent module in a certain range of reentry angles with load factor constraints

Results concerning the terminal guidance algorithm at the reentry of the descent module into the Earth atmosphere are presented. This algorithm simultaneously eliminates predicted deviations in the downrange and crossrange directions. The restriction on the tolerable load factor n ?? 3 is taken into account. Three reentry angles are analyzed: the medium angle ?1.5°, the steep angle ?1.9°, and the flat angle ?1.2°. The motion of the descent module is considered in the disturbed Earth atmosphere represented by the TsNIIMash model. This model includes variations of the atmosphere density and the wind field. It is demonstrated that, depending on the reentry angle, the proposed algorithm guarantees the downrange maneuver zone in the range 1240?C1890 km and the crossrange maneuver zone of 210?C220 km on one side. The maximum guidance error at the altitude of 1 km does not exceed 0.8 km, and the average error is 0.1 km. The algorithm uses up to three bank angle reversals and uses the numerical prediction of the remaining part of the trajectory when choosing the guidance parameters. The concept of the automatic adjustment of the bank angle reference function depending on the entry angle and the prescribed distance to the target point in the maneuver zone is formulated.     

A concept of the terminal descent control algorithm at reentry into the earth atmosphere with near-parabolic velocity

A concept of the terminal descent control algorithm of the descent module at reentry into the Earth atmosphere with near-parabolic velocity is proposed. Trajectories with one and two (skip reentry) reentries are considered. Simultaneously, downrange and crossrange misses are eliminated by controlling the bank angle and time of bank angle reversal at each phase of the trajectory. The designed control meets the specified load factor constraint.     

Terminal control algorithm for the downrange motion of a descent module with load factor constraints

Results concerning the terminal guidance algorithm at the reentry of the descent module into the Earth atmosphere are presented. This algorithm simultaneously eliminates predicted errors in the longitudinal and lateral directions. The restriction on the load factor n ?? 3 is taken into account. The motion of the descent module is considered in the disturbed Earth atmosphere using two of global atmosphere models??the TsNIIMash model created in due time for the Energy-Buran project and the Computational Model of the Earth Disturbed Atmosphere (CMEDA) developed in the Keldysh Institute of Applied Mathematics. It is demonstrated that the proposed algorithm guarantees the downrange maneuver zone of 1500 km with a guidance error less than 1 km using three reversals of the bank angle when the descent module enters the atmosphere at an angle of ?1.5°. The algorithm automatically adjusts the parameters of the bank angle control function depending on the distance to the desired target in the maneuver zone. For small ranges to the target, the constant load factor mode is realized. For large ranges to the target, sufficient store of energy is reserved for eliminating singular controls. For medium ranges to the target, the so-called k _?? mode is used to balance the load factor maximums on the first and the second halves of the descent trajectory.     

Construction of the reachability region with regard to the attitude motion of a descent module at reentry with near-circular velocity

A model of the general motion of the descent module that includes the motion of its center of mass and the attitude motion is constructed. An improved estimate of the reachability region in the case of descent in the disturbed Earth atmosphere is obtained. A terminal descent control algorithm with three bank angle reversals for the simultaneous elimination of predicted downrange and cross-range errors with regard to the constraint on the tolerable load factor n _tol ≤ 3 is used.     

Design of longitudinal predictive re-entry guidance law based on variable universe fuzzy-PI composite control

This paper studies the longitudinal predictive re-entry guidance law based on the variable universe fuzzy-PI composite control to overcome the inaccuracy of the reference trajectory re-entry guidance for re-entry vehicles. The variable universe fuzzy controller is used to obtain a satisfactory dynamic response when the downrange error is large, and the PI controller is utilized to eliminate the steady-state error when the downrange error is small. Simulation results show that the proposed guidance law is very robust to the initial errors and can achieve better accuracy, and is also able to handle the effect of the stochastic errors in re-entry processes.     

载人登月飞行器高速返回再入制导技术研究

返回再入段是载人登月任务完成后,保证宇航员安全返回地球的关键阶段,其跳跃式再入制导方法的研究是我国载人登月任务需要突破的一项重要关键技术.由于探月返回飞行器速度极高,其弹道特性与神舟飞船一类的近地轨道返回的飞行器有较大差别,也给制导导航与控制(简称GNC,以下同)系统设计带来较大挑战.与无人再入飞行器相比,载人飞行器需要具备防过载超限能力、大范围再入航程适应能力、高精度落点控制能力.为了满足上述要求,本文提出了一套基于全系数自适应校正的预测制导方案.在再入前,通过对基本倾侧角进行校正,提高了规划弹道对再入初始条件散布的适应性;再入后利用外环的预测与全系数自适应校正实现对规划弹道的持续修正,保证规划弹道与飞行器状态的匹配性,内环则采用短周期的弹道跟踪制导;对于横向制导,本文给出和比较了采用实时漏斗制导律、独立预测–校正制导律方案以及横航向独立自校正和耦合自校正方案.     

三维自主再入制导方法

基于阻力加速度-能量剖面设计,提出一种新的三维自主再入制导方法.该方法的阻力加速度-能量剖面由再入走廊上边界和下边界内插得到,倾侧角采用两次反转模式,轨迹规划同时考虑了飞行器的纵向和横向运动,并具有在线生成三维轨迹的能力.最后对制导方法的适应性进行了仿真分析,仿真结果表明给出的再入制导方法能适应不同情况的再入,使飞行器在具有较好轨迹特性的同时以较高的精度到达末端能量管理界面.     

New adaptive approaches to real-time estimation of vehicle sideslip angle

This paper presents new approaches to the identification of the vehicle sideslip angle and the road bank angle in real-time. The major challenge is that the vehicle sideslip angle and the road bank angle are coupled together with the system uncertainties, such as variations in the vehicle parameters and the tire cornering stiffness. To resolve this difficulty, the proposed estimation algorithms identify the uncertain vehicle parameters using the sensor measurements such as the steering angle, the lateral acceleration and the yaw rate, and then estimate the vehicle sideslip angle and the road bank angle via a simple algebraic relationship in real time. In particular, the use of the lateral G sensor signal makes it possible to identify the cornering stiffness and vehicle sideslip angle without any a priori knowledge on the road bank angle. The performance of the proposed algorithms is verified through simulation and experimental results.     

滑模变结构有限时间收敛制导律

针对末端有入射角度约束的制导系统,基于滑模变结构控制思想设计了一种有限时间收敛的滑模制导律,使制导系统的视线角速率快速收敛到零,并令弹道倾角收敛到期望的入射角度.通过非线性控制系统的有限时间稳定性理论对该制导律进行了分析,给出了制导系统有限收敛时间的数学形式,证明了制导系统的有限时间收敛性.最后通过仿真进一步验证了该制导方法的有效性和鲁棒性.     

基于变结构控制的固定前置角制导律设计

弹载合成孔径雷达（SAR）的方位成像能力受飞行导弹的观测角影响,其末制导段采用前侧视工作方式。因此,必需合理设计制导律使前侧视条件成立。为了保证末制导段弹目间具有合适的夹角,采用变结构控制方法设计了一种固定前置角制导律,该制导律能够解决合成孔径雷达导引头对于前置角约束的问题。在制导律设计过程中,首先建立了弹目相对运动关系模型和具有终端角度约束时的视线角变化模型;在此基础上采用变结构控制的方法设计了固定前置角制导律;进而,对该固定前置角导引律进行了性能分析,得出了其一般攻击特性;最后,通过弹道仿真论证了其正确性与有效性。     

Integrated aircraft control for rendezvous of aircraft-launched missiles with radiating targets

This paper solves the problem of rendezvous of an aircraft-launched missile with a maneuvering radiating target so as to maximize the launch range (agreed launch conditions). The information maneuver (vertical, horizontal, and spatial) of the aircraft that maximally improves the accuracy of radiating target tracking and is executed before the aircraft meets the agreed launch conditions is determined. An algorithm for determining the current demands for aircraft control with respect to bank angle and load factor is developed to solve the problem of rendezvous with each tracked target. The integrated aircraft control is based on choosing a priority target at the current time and supplying the current control demand in terms of the desired bank angle and load factor.     

含攻击角约束的网络化弹药分布式模糊协同制导律

在舰炮网络化弹药打击近岸机动目标的末制导段,提出了一种考虑攻击角约束的有限时间分布式模糊协同制导律.构建网络化弹药–目标相对运动模型,设计扩张状态观测器估计目标的切向、法向加速度.在视线切向,为保证命中时刻在有限时间内趋于一致,采用积分滑模设计分布式有限时间协同制导律;在视线法向,为在有限时间内零化视线角误差、视线角速率并改善控制指令终端发散现象,采用非奇异终端滑模设计两阶段制导律.为削弱控制指令抖振、补偿干扰,设计模糊自适应系统,并通过Lyapunov理论证明了全系统状态的一致最终有界性与有限时间收敛性.仿真实验表明:该制导律使网络化弹药在打击机动形式不同的目标时,均具备较好的协同制导性能.     

高精度微波引导设备角度数据检测系统设计与实现

针对当前某高精度微波引导设备的角度制导性能精准检测难度大的问题,基于ARM+DSP+FPGA的总体架构,研究并搭建了高精度角度数据检测系统的硬件电路结构,基于C/C++、VHDL和Verilog开发了角度数据测试软硬件程序,实现了对微波引导设备空间角度、数据信号的接收、处理、解算和测量;并进行试验验证,结果表明该系统实现了设计功能、达到了指标要求,对高精度微波引导设备角度测量方位角优于0.16°,仰角优于0.18°,数据字与设备预置信息一致,满足高精度角度、数据的检测要求,对有效提高该微波引导设备的可靠性具有重要意义。     

考虑导弹速度时变的角度约束最优中制导律

以导弹逆轨拦截高速运动目标为背景,本文运用间接高斯伪谱法设计带攻击角度约束的最优中制导律.通过零化弹目相对法向速度,将攻击角度约束转化为视线角约束.考虑导弹速度时变的情况,建立带角度约束的制导方程.根据极小值原理推导最优中制导律的解析表达式,运用高斯伪谱法对最优中制导律进行离散化,把微分方程转化为代数方程,避免了求解Riccati方程.该方法不需要预先知道导弹未来的速度信息,计算量小,具有较好的实时性.仿真结果表明该中制导律可以满足逆轨拦截对弹目交会角的约束,且中制导末端的过载较小.     

Terminal angle constrained time-varying sliding mode guidance law with autopilot dynamics and input saturation

To intercept the maneuvering target at a desired terminal angle, this paper presents a time-varying sliding mode guidance law with consideration of the second-order autopilot dynamics and input saturation. To achieve the finite-time interception and satisfactory overload characteristics, a time-varying sliding mode guidance law is developed, which enables the line-of-sight (LOS) angle error to converge into a small neighborhood of the origin at the interception time. An auxiliary system is constructed to reduce the adverse effect generated from the input saturation. Moreover, with the aid of extended state observers, the proposed guidance law requires no information on the target acceleration and the acceleration derivative of the interceptor. The performance of this guidance law is verified via the numerical simulations.     

基于Bézier曲线的碰撞角约束多项式制导方法

研究了一种基于Bézier曲线的碰撞角约束的制导律.通过模型转化将制导指令设计的问题转化为二次Bézier曲线形式的航迹角设计问题.首先,利用Bézier曲线的性质设计了导弹速度大小不变的制导律;然后进一步对导弹速度时变的末端角度约束的制导律进行了研究,同时对导弹速度时变情形下的剩余飞行时间进行了估计;最后通过不同情况下的数值仿真,验证了所提出的制导律的有效性.     

导弹制导的鲁棒几何方法

针对平面拦截问题,将基于微分几何的导弹制导与基于李雅普诺夫稳定理论的鲁棒控制方法结合起来,提出一种新的鲁棒制导算法———鲁棒几何制导.将与目标的曲率命令(加速度)和速度方位信息有关的项视为干扰量,用一个鲁棒控制项来克服其影响.然后,将这种方法推广到导弹速度变化的情况.这种方法不需要得到目标精确的曲率命令和速度方位信息.仿真结果验证了该方法对目标机动具有强的鲁棒性.     

基于CNN 的银行卡数字识别方法

在拍摄银行卡时,由于受拍摄角度的不确定性、光照条件的复杂性及卡背景的多 样性等众多因素的干扰,使得自然拍摄场景的银行卡数字识别算法存在较大挑战。为此,提出 一种基于卷积神经网络(CNN)的银行卡数字识别框架。首先,通过投影矫正、边缘检测和形态 学等一系列图像处理算法获取目标数字区域;其次,通过增强的数据集训练一个CNN,使用该 网络通过滑窗识别获取上述目标数字区域,输出初始银行卡号序列,生成为一个数字曲线图; 最后,提出了滑窗优化算法,该平滑算法输入上述初始的银行卡号曲线图,对其进行优化,继 而分割出单个数字并输出最终结果。实验结果表明算法显著提高了银行卡数字识别和分割的准 确率,同时针对较复杂的银行卡图像仍然具有较好的鲁棒性。     

我国商业银行综合业务软件结构发展趋势探

综合业务软件作为我国商业银行的主要业务软件,历来受到我国商业银行业内人士及软件界人士的高度关注.在科学技术日新月异、商业银行业务蓬勃发展的今天,我国商业银行综合业务软件的开发结构又将走向何方?本文从一个银行从业人员的角度,就我国商业银行综合业务软件结构的走向作了初步探讨.     

带攻击角度约束的非奇异快速终端滑模制导律

本文利用先进的终端滑模控制和李雅普诺夫稳定性理论设计了一种非奇异、本质上连续和有限时间收敛的带攻击角度约束的制导律,它可用于打击固定、匀速运动和机动目标.为了在有限时间内高精度地获得给定的攻击角度并不出现奇异问题,非奇异快速终端滑模函数被用于设计滑模面.快速终端滑模函数被用于设计趋近律,在整个到达阶段系统轨迹可以从任意初始状态快速地收敛到滑模面并形成本质上连续的制导律.由于非奇异、本质上连续和全局快速收敛的特性,和传统的终端滑模制导律相比,本文方法可以在更短时间内以更高精度的攻击角度对目标实施打击.大量的仿真算例表明了本文制导律的有效性.