Research on aiming methods for small sample size shooting tests of two-dimensional trajectory correction fuse

The longitudinal dispersion of the projectile in shooting tests of two-dimensional trajectory corrections fused with fixed canards is extremely large that it sometimes exceeds the correction ability of the correction fuse actuator.The impact point easily deviates from the target,and thus the correction result cannot be readily evaluated.However,the cost of shooting tests is considerably high to conduct many tests for data collection.To address this issue,this study proposes an aiming method for shooting tests based on small sample size.The proposed method uses the Bootstrap method to expand the test data;repeatedly iterates and corrects the position of the simulated theoretical impact points through an improved compatibility test method;and dynamically adjusts the weight of the prior distribution of simulation results based on Kullback-Leibler divergence,which to some extent avoids the real data being"submerged"by the simulation data and achieves the fusion Bayesian estimation of the dispersion center.The experimental results show that when the simulation accuracy is sufficiently high,the proposed method yields a smaller mean-square deviation in estimating the dispersion center and higher shooting accuracy than those of the three comparison methods,which is more conducive to reflecting the effect of the control algorithm and facilitating test personnel to iterate their proposed structures and algorithms.;in addition,this study provides a knowledge base for further comprehensive studies in the future.

Ground target localization algorithm for semi-active laser terminalcorrection projectile

A target localization algorithm,which uses the measurement information from onboard GPS and onboard laser detector to acquire the target position,is proposed to obtain the accurate position of ground target in real time in the trajectory correction process of semi-active laser terminal correction projectile.A target localization model is established according to projectile position,attitude and line-of-sight angle.The effects of measurement errors of projectile position,attitude and line-of-sight angle on localization accuracy at different quadrant elevation angles are analyzed through Monte-Carlo simulation.The simulation results show that the measurement error of line-of-sight angle has the largest influence on the localization accuracy.The localization accuracy decreases with the increase in quadrant elevation angle.However,the maximum localization accuracy is less than 7 m.The proposed algorithm meets the accuracy and real-time requirements of target localization.

Key Techniques of Terminal Correction Mortar Projectiles

The operational principle, the impulse force and terminal guidance laws of terminal correction mortar projectiles（TCMP） are researched in this paper, by using the TCMP simulation program, key techniques such as the miss distance influenced by the acting point of impulse force, the impulse force value, the correction threshold, and the number of impulse rockets are researched in this paper. And the dual pulse control scheme is also studied. Simulation results indicate that the best acting point is near the center of gravity, sufficient correction resources are needed, the miss distance is insentive to the correction threshold, increasing the number of impulse rockets properly is beneficial to increase the hit precision, the velocity pursuit guidance law has less miss distance, the change of the attack angle is milder and the transient time becomes less in the dual impulse control scheme. These conclusions are important for choosing parameters and impulse correction schemes designed for TCMP.

Control System in Missiles for Whole-Trajectory-Controlled Trajectory Correction Projectile Based on DSP

A control system for correction mechanisms through the whole trajectory is proposed based on the principle of one-dimensional trajectory correction projectile. Digital signal processing( DSP) is utilized as the core controller and gobal positioning system( GPS) is used to measure trajectory parameters to meet the requirements of calculating ballistics and system functions. Firstly,the hardware,mainly including communication module,ballistic calculation module,boosting& detonating module and data storage module,is designed. Secondly,the supporting software is developed based on the communication protocols of GPS and the workflow of control system. Finally,the feasibility and the reliability of the control system are verified through dynamic tests in a car and live firing experiments. The system lays a foundation for the research on trajectory correction projectile for the whole trajectory.

Study on Overall Concept Planning of Terminal Correction Mortar Projectiles

The system composition, the operational principle of terminal correction mortar projectiles （TCMP） and the concept planning design of TCMP are researched in this paper. An overall design and aerodynamic configuration layout for TCMP are made in this paper, and its aerodynamic coefficients are calculated by using computational fluid dynamics （CFD） software. Test results of TCMP simulated ballistic projectiles indicate the designed TCMP can satisfy the interior ballistic demand and has a fine flight stability. The drag coefficients identified from the radar velocity-time data are in accord with the CFD computed results. According to the exposure frequency of the ground laser designator, a four-quadrant impulse correction scheme and a high exposure frequency impulse correction scheme are brought. The latter can calculate the target azimuth angle by counting the times of the facula passing through one quadrant. Simulation results also show that the guidance precision of the velocity pursuit is higher than that of the body pursuit, and the detector axis is less circuitous. Researches on the typical trajectory indicate that the terminal impulse correction can improve the hit precision of TCMP remarkably.

Effects of Wind on Steady-state Scan Characteristics and Hit Probability of Terminal-sensitive Projectile

The wind effects on steady-state scan characteristics and hit probability of terminal-sensitive projectile were discussed in this paper. Considering wind as the constitutions of the average wind and the impulsive wind, a simplified wind field model was established for the ballistic calculation of the steady-state scan phase; under the windy condition, the effects of the range wind and the beam wind on the steady-state scan characteristics of the terminal-sensitive projectile were analyzed in detail and its hit probabilities for a certain armored target were calculated. The calculated results show that, when the wind speed exceeds a certain value, the hit probabilities of terminal-sensitive projectile drop rapidly; the wind effects must be considered in the application of the terminal-sensitive projectiles. This paper provides some theoretical references for the fire wind speed correction and the global structure optimization of the terminal-sensitive projectile.

Influence of yawing force frequency on angular motion and ballistic characteristics of a dual-spin projectile

A roll-decoupled course correction fuze with canards can improve the hit accuracy of conventional unguided ammunitions. The fuze increases accuracy by reducing the effect of angular and translational motion produced by the cyclical yawing forces applied on the projectile. In order to investigate the influence of yawing forces on angular motion, a theoretical solution of the total yaw angle function with the cyclical yawing forces is deduced utilizing the 7 degrees of freedom(7-DOF) model designed for this calculation. Furthermore, a detailed simulation is carried out to determine the influence rules of yawing force on angular motion. The calculated results illustrate that, when the rotational speed of the forward part is close to the initial turning rate, the total yaw angle increases and the flight range decreases sharply. Moreover, a yawing force at an appropriate frequency is able to correct the gun azimuth and elevation perturbation to some extent.

Real-time measurement of high rotational projectile axial acceleration based on 2-axis acceleration sensor

The real-time measurement principle of high rotational projectile＇s angular velocity based on 2-axis acceleration sensor and the axial acceleration measurement error caused by the installation error are discussed.The 2-axis acceleration sensor is applied to measure the high rotational projectile＇s angular velocity and the measurement value of axial acceleration,the axial acceleration of the high rotational projectile equals the measurement value of axial acceleration subtracting the centrifugal acceleration component,so that the high-accuracy real-time measurement of axial acceleration is realized.The memory test has confirmed the strike tally of the theoretical analysis and the test result.The measurement technique can satisfy the high-accuracy measurement of the high rotational projectile axial acceleration in the self-determination course correction fuze projectile.

Dynamic inverse control of feedback linearization in ballistic correction based on nose cone swinging

It is a complicated nonlinear controlling problem to conduct a two-dimensional trajectory correction of rockets.By establishing the aerodynamic correction force mathematical model of rockets on nose cone swinging,the linear control is realized by the dynamic inverse nonlinear controlling theory and the three-time-scale separation method.The control ability and the simulation results are also tested and verified.The results show that the output responses of system track the expected curve well and the error is controlled in a given margin.The maximum correction is about±314 m in the lengthwise direction and±1 212 m in the crosswise direction from the moment of 5 s to the drop-point time when the angle of fire is 55°.Thus,based on the dynamic inverse control of feedback linearization,the trajectory correction capability of nose cone swinging can satisfy the requirements of two-dimensional ballistic correction,and the validity and effectiveness of the method are proved.

高旋弹二维修正引信双旋结构气动特性及气动力表征

针对配二维弹道修正引信高旋弹具有弹体气动参数非对称、纵向和横向修正紧密耦合等问题,为了准确表征高旋弹气动参数、明确修正弹丸气动特性和产生机理,提出了基于CFD(computational fluid dynamics)仿真的双旋结构气动力计算分析方法.在构建双滚转域流场仿真模型的基础上,对比了二维修正引信不同控制状态下的弹丸受力情况;明确了高旋弹固有气动力和二维修正引信所引起的气动力;建立并推导了攻角与滚转角耦合情况下的舵片受力模型.研究表明:针对二维修正组件,需要考虑合攻角与舵滚转角的相对位置关系以计算诱导阻力;受迎背风和舵片绕流影响,舵片受力模型和弹体的横、纵向气动力均随攻角、滚转角及马赫数变化.

鸭式布局二维修正双旋弹角运动及转向响应特性分析

为研究鸭式布局双旋弹受控状态下的动态响应规律,对弹丸角运动特性及转向响应特性进行理论分析。基于7自由度刚体弹道模型,求解弹丸受控状态下的攻角瞬态及稳态解析解,并推导弹丸瞬态及稳态转向响应解析表达式。研究控制指令更新周期、射角、转速及初速对转向响应特性的影响。研究结果表明:输入控制力方向对转向响应相移角影响较小;控制指令更新周期较短时,在弹道顶点相移角瞬态解与稳态解相差较大,采用瞬态解修正后弹丸横纵向耦合程度较低,随着指令更新周期的增大,转向响应相移角瞬态解逐渐趋于稳态解;相移角稳态解随转速增加而减小,随初速增加而增加。通过实验数据验证了理论的正确性。研究结果可为鸭式布局双旋弹二维修正控制系统分析设计提供理论依据。

一种新型后舵尾控修正弹的弹道控制仿真

为增强修正弹控制舵的快速响应能力和弹道修正效果,且理论上减弱舵片在高旋状态下对弹体的气动扰流影响,设计一种控制舵置于质心后部、与弹尾部高度配合的新型二维修正弹。建立弹体模型,设计以优化后的新式制导方案和比例微积分控制法为主体的组合控制策略,分析无控和有控状态下关键变量参数的变化规律,对基于参数最优值下的弹道修正过程进行仿真计算;采用蒙特卡洛打靶法分析扰动状态下的落点散布情况。仿真结果表明:此控制策略下后舵尾控弹的实际滚转角吻合于输入指令,整个过程速度高低角和方向角的变化范围仅为2°和7°,基于最优值的控制修正过程和扰动状态下的最终落点情况也保证了弹体进行平稳运动的同时具备更优的偏差修正能力,进一步证实了设计的新型弹体模型具有较高的可行性和参考价值。

Two-dimensional precise figuring of 500 mm-long X-ray mirror using one-dimensional ion beam system

In this study,a new method was developed to realize two-dimensional(2D)figure correction of grazing-incidence X-ray mirrors using a one-dimensional(1D)ion-beam figuring system.A mask of holes was specifically designed to generate removal functions at different widths and extend the figuring capability over a wide area.Accordingly,a long mirror could be manufactured.Using this method,the surface height root-mean-square(RMS)error of the center area of 484 mm×16 mm was reduced from 11.49 nm to 2.01 nm,and the 1D meridional RMS error reached 1.0 nm.The proposed method exhibits high precision and cost effectiveness for production of long X-ray mirrors.

基于MPC和RBF神经网络的火箭弹姿态调整策略

火箭弹的精准飞行控制目前是国内外军事领域研究中的一个热点话题。针对火箭弹如何能够更好的打击实现精确打击这一问题,提出一种基于模型预测控制和径向基函数神经网络相结合的火箭弹姿态调整策略。该策略利用模型预测控制算法预测得到姿态调整所需的最优的电机修正值,然后利用径向基函数神经网络算法实现对电机的快速调节响应,以此达到调整姿态修正弹道的目的。仿真结果表明,舵控系统的调整过程误差小、反应快、跟踪效果良好,整体策略具有优良的控制性能。使火箭弹飞行姿态控制系统的鲁棒性和快速性得到了很大的提高。很好的将模型预测算法与径向基函数神经网络算法的优点结合到了一起。

鸭舵式修正弹弹道模型建立与仿真分析

为研究鸭舵式修正机构的修正能力,以某口径高速旋转稳定弹为模型,研究鸭舵对弹丸的作用力和力矩以及弹丸所受空气动力;并在弹箭外弹道学的理论基础上,利用外弹道学常用坐标系及它们之间的转换关系,构建出鸭舵式修正弹七自由度刚体运动方程的数学模型。基于气动分析结果,采用四阶龙格-库塔方法计算得到修正弹的外弹道参数,得出仿真弹道轨迹,并与实际弹道轨迹进行初步对比。研究结果表明,鸭舵式修正机构的仿真分析与实际弹道轨迹相符,并能够对修正能力进行预测。

弹道修正弹技术发展综述

炮弹在发射和飞行的过程中,受各种随机误差的影响,造成射弹散布。设法减小或控制随机误差影响、改善炮弹地面密集度,始终是常规弹箭技术研究的方向。近年来研究者另辟蹊径,发展和研究了弹道修正理论与技术,即通过对一段实测飞行弹道参数的在线误差影响辨识,后续弹道预报,并通过弹上简易机构进行弹道修正调节,实现低成本下大幅度改善炮弹地面密集度。该文综合近年来国内外部分文献资料报道,结合多年的研究经验,对弹道修正弹技术的特点、难点及其工程应用中存在的射程扩展量等作一介绍,对未来的技术发展作一展望,以期为从事这方面研究的人员提供参考。

弹道修正弹脉冲修正机构简易控制方法

建立了采用脉冲力控制的弹道修正弹飞行弹道模型.利用均匀设计方法,通过回归分析研究了脉冲修正起始时间、脉冲力级数、弹丸射角以及作用角度对修正效果的影响,推导出关系模型,利用该模型提出了一种简易的脉冲力控制方法.仿真结果证实该简易方法控制脉冲发动机工作能够有效提高弹丸的命中精度,对脉冲发动机在弹道修正弹上的工程应用有一定的参考意义.

卡尔曼滤波在弹道修正弹落点推算中的应用

为了准确地估算常规弹箭的飞行弹道，以便对其实施简易弹道修正并大幅度提高弹箭的密集度，应用卡尔曼滤波方法，结合质点弹道模型，建立了卡尔曼滤波弹道模型．对地面侦察雷达探测到的一段飞行弹道参数进行滤波，进而外推出弹道落点．仿真结果表明，雷达测量信号中的噪声具有随机性且幅值较大，在卡尔曼滤波过程中，滤波方差衰减很快，滤波后测量噪声能够较快地大幅度减小；外推弹道落点精度随着雷达跟踪时间（跟踪点数）的增加而迅速提高，经过一段跟踪时间后，这种趋势逐渐变缓．对于大口径弹道修正弹，雷达跟踪点数宜取30～40点，求解一条弹道约需几十ms．

隔转鸭舵式弹道修正弹气动力工程模型与辨识

修正弹的气动力可表示为外形和飞行状态的函数,其模型直接影响动力学系统求解的准确性。在风洞试验数据的基础上,建立适用于隔转鸭舵式弹道修正弹的气动力工程模型。模型综合考虑复攻角和鸭舵相位角的复合效应,并利用最小二乘方法对修正弹阻力、升力、侧向力以及俯仰力矩的工程模型进行参数辨识,模型预测结果得到了计算流体力学计算的验证。结果表明:鸭舵的诱导阻力较小,小攻角范围内利用对称拟合表征修正弹阻力的误差小于3.3%;在攻角和鸭舵相位角的综合影响下,升力表现为正弦特性,侧向力在鸭舵相位角为180°时会出现二次正弦叠加现象。气动力模型为隔转鸭舵式弹道修正弹的飞行特性分析奠定了基础。

迫弹横向脉冲控制飞行稳定性

为了研究迫弹利用脉冲发动机进行弹道修正而引起的飞行稳定性问题,分析了横向脉冲控制力及控制力矩,建立了有控弹道模型,在一定的假设条件下推导出脉冲作用段迫弹的攻角方程,讨论了脉冲作用段迫弹的飞行稳定性,给出了脉冲冲量大小及距质心作用距离的约束条件.研究表明,正常情况下,横向脉冲控制对迫弹的动稳定条件、追随稳定条件及共振不稳定条件没有影响,但需控制脉冲冲量大小和距质心作用距离,使得扰动引起的攻角增量幅值不超过允许的极限值,保证迫弹在脉冲作用后仍能稳定飞行.