Optimal Gliding Guidance of Vertical Plane for Standoff Released Guided Bomb Unit

Optimal gliding guidance for a guided bomb unit in the vertical plane is studied based on nonlinear dynamics and kinematics.The guidance law is designed under minimum energy loss index.To avoid the complexity in solving two-point-boundary-value problems,the steady-state solutions of the adjoint states in regular equations are suggested to be used.With these considerations,a quasi-closed,optimal gliding guidance law is obtained.The guidance law is described by the angle of attack in a simple nonlinear equation.An iterative computation method can be easily used to get the optimal angle of attack.The further simplified direct computation algorithm for the optimal angle of attack is also given.The guidance properties are compared with those of maximum lift-to-drag angle of attack control.The simulation results demonstrate that the quasi-closed,optimal gliding guidance law can improve the gliding phase terminal performance with significant increase in the altitude and much little decrease in the speed.     

Biased retro-proportional navigation law for interception of high-speed targets with angular constraint

A new guidance law, called biased retro proportional navigation （BRPN）, is proposed. The guidance law is designed to intercept high-speed targets with angular constraint, which can be used for ballistic target interception. BRPN guidance law is defined, and the exact time-varying bias for a required impact angle is derived. Furthermore, the simulation results （trajectory, variation of navigation ratio, capture region, etc） are compared with those of biased proportional navigation （BPN）, proportional navigation and retro-proportional navigation. The results show that, at the cost of a higher intercept time, BRPN demands lower terminal lateral acceleration and has larger capture region compared to BPN.     

Research on Airborne Electro-Optical Tracking and Sighting System Based on Fuzzy PID and H∞ Control

Airborne electro-optical tracking and sighting system is a three-degree-of-freedom angular position servo system which is influenced by multi-disturbance, and its control system consists of stabilizing and tracking components. Stabilizing control is applied to track angular velocity order and control multi-disturbance under airborne condition, and its robustness should be very good; tracking control is applied to compensate tracking error of angular position. A mathematical model is established by taking the control of yaw loop as example. H∞ stabilizing controller is designed by taking the advantage of H∞ control robustness and combining with Kalman filter. A fuzzy control is introduced in general PID control to design a decoupled fuzzy Smith estimating PID controller for tracking control. Simulation research shows that the control effect of airborne electro-optical tracking and sighting system based on fuzzy PID and H∞ control is good, especially when the model parameters change and the multi-disturbance exists, the system capability has little fall, but this system still can effectively track a target.     

Underwater Localization for Multiple AUVs Based on Bearing and Range Measurements

A novel underwater localization algorithm for autonomous underwater vehicle （AUVs） is proposed. Taking aim at the high cost of the traditional ＂leader-follower＂ positioning, a ＂parallel＂ model is adopted to describe the localization problem. Under an unknown-but-bounded assumption for sensor noise, bearing and range measurements can be modeled as linear constraints on the configuration space of the AUVs. Merged these constraints, a convex polyhedron representing the set of all configurations consistent with the sensor measurements can be induced. Estimates for the,uncertainty in the position of a single AUV or the relative positions of two or more AUVs can then be obtained by projecting this polyhedron into appropriate subspaces of the configuration space. The localization uncertain region for each AUV can be recovered by an approximation algorithm to realize underwater localization for multiple AUVs. The deduced theoretically and the simulated results show that it is an economical and practical localization method for the AUV swarm.     

Design and Simulation of TF and TA Controller for Missile

A nonlinear terrain following(TF) and terrain avoidance(TA) controller is proposed for missile control systems. Based on classical TF algorithm (adaptive angle method), a new method for TF controller is proposed by using angle of attack. A method of obtaining terrain outline data from digital elevation map (DEM) for TF control is discussed in order to save store space. A TA algorithm is proposed by using bank-to-turn technique. The block control model, which is suitable for backstepping design, is given for nonlinear model of missile. Making full use of the characteristics of the system and combining block control principle and backstepping technique, a robust controller design method is proposed. Uncertainties in every sub-block are allowed, and can be canceled by using the idea of nonlinear damping. It is proved that the state tracking errors are converged to a neighborhood of the origin exponentially. Finally, nonlinear six-degree-of-freedom simulation results for the missile model are presented to demonstrate the effectiveness of the proposed control law.     

Guidance Law Design Under Impact Angle Constraint Based on Nussbaum-type Gain Technique

Aiming at the guidance problem under impact angle constraint for homing missile against ground targets,a new adaptive robust nonlinear terminal guidance law was proposed in this paper.According to nonlinear kinetic relationship between the missile and target in vertical plane,a mathematic model was formulated while the motion of target and the system structure perturbation were regarded as limited disturbances.Based on the ideas of zeroing the rate of line-of-sight(LOS)angle and the impact angular tracking error,a nonlinear control strategy was contrived to obtain adaptive robust guidance law by adopting Nussbaum-type gain technique under a desired impact angle.The stability of guidance system in finite time is strictly proven by using Lyapunov stability theory.Finally,the numerical simulation verifies the effectiveness of the proposed scheme.     

Design of Neural Network Variable Structure Reentry Control System for Reusable Launch Vehicle

A flight control system is designed for a reusable launch vehicle with aerodynamic control surfaces and reaction control system based on a variable-structure control and neural network theory.The control problems of coupling among the channels and the uncertainty of model parameters are solved by using the method.High precise and robust tracking of required attitude angles can be achieved in complicated air space.A mathematical model of reusable launch vehicle is presented first,and then a controller of flight system is presented.Base on the mathematical model,the controller is divided into two parts：variable-structure controller and neural network module which is used to modify the parameters of controller.This control system decouples the lateraldirectional tunnels well with a neural network sliding mode controller and provides a robust and de-coupled tracking for mission angle profiles.After this a control allocation algorithm is employed to allocate the torque moments to aerodynamic control surfaces and thrusters.The final simulation shows that the control system has a good accurate,robust and de-coupled tracking performance.The stable state error is less than 1°,and the overshoot is less than 5%.     

Position Adaptive Measurement Model for Double-four Quadrant Photoelectric Detector

A modeling method of the support vector machine combined with matrix optics is considered; a complete new measurement model for double-four quadrant photoelectric detector is built. According to the analysis of the received light spot size and its motion with the changes of the defocusing amount of detector photosensitive surface and the detector position attitude in the optical path, a mathematic expression of photoelectrical conversion is given, which can be applicable to random setting position of the detector at any time. Based on least square support vector machine （LS SVM）, the mapping relationship among the output signal linear characteristic parameters （zero neighborhood gradient and intercept）, the defocusing amount of the detector and the installation position attitude angle is established. Thus, the multiple dimensional high accuracy measuring and adjusting control system can be left out, and adaptive measurement of the detector parameters can be realized. Compared with existed measurement model and method, the presented model has the advantages of more clear physical meaning, closer to work mechanism of detector, acquiring more complete sample data and wiping out the dead spots or bad spots in measurement. And the accuracy of displacement measurement is increased to 3μm. At the same time, this measurement mode provides a technical shortcut for three-dimensional small angle measurement.     

Study on Guidance Law of UAV Net Recovery System

The design and realization of a net recovery system is introduced, which can recover UAV （unmanned aerial vehicle） reliably and safely. The mathematical model is built, and the horizontal and vertical guidance law is studied based on the aerodynamic parameters and actual flying trial data of a certain UAV. The simulation result shows that this system can realize the recovery safely, stably and accurately.     

导弹制导的协同控制方法

针对导弹制导系统中存在的模型不确定性和外部扰动,研究了末制导规律的设计与实现问题。首先,建立了导弹三维制导的运动学模型,描述了俯仰通道和偏航通道之间的耦合关系。其次,针对无终端约束和有终端约束情况,基于协同控制理论分别设计了非线性制导规律。然后,将制导模型中的目标机动加速度、通道耦合项及量测误差视为系统总扰动,利用扩张状态观测器对其进行估计,并分析了闭环系统的稳定性。所得制导律不依赖于系统精确的数学模型,不需要太多的观测信息。仿真结果表明,该制导律既能用于目标机动的制导,也能用于有终端约束的制导,且具有良好的制导精度,鲁棒性较强。     

多约束条件下对地攻击的最优制导律

针对现代空地武器多约束、高精度制导的基本需求，本文将空地武器三维运动分解成俯仰平面和转弯平面两个平面运动，以此为基础分别设计制导律。在制导律设计过程中，综合考虑脱靶量、落角、入射角、导弹动态特性等多约束条件，运用二次型最优控制的黎卡提方程推导出一种新的韦0导律，并给出了0阶无时延系统的近似表达式。最后运用典型弹道仿真和对比试验验证了该制导律的可行性和良好的弹道性能。结果显示该制导律不但能够满足多约束高精度制导的需要，而且对末端攻角控制和早期弹道修正具有较大的优势。     

垂直命中机动目标的鱼雷三维拦截导引律设计

本文研究了三维空间中鱼雷垂直命中机动目标的最优导引律设计问题。首先将拦截几何的非线性模型变为模糊 T- S线性模型 ,然后利用 RH控制方法和伴随技术 ,在目标作对抗性机动条件下 ,获得了垂直命中机动目标的三维拦截导引律。仿真结果表明 ,这种导引律能够达到较高的点命中和角命中拦截精度。     

考虑自动驾驶仪特性的自适应模糊动态面滑模制导律设计

针对导弹拦截高机动性目标的问题,基于自适应模糊逼近策略和动态面滑模控制思想,提出了一种新型的拦截制导律。建立了考虑自动驾驶仪动态延迟特性的弹目相对运动方程,以零化视线角速率为出发点,设计了基于自适应趋近率的动态面滑模制导律,同时设计了综合视线角速率以及弹目距离的自适应模糊方法,对变结构项进行逼近。仿真结果表明,针对高机动性目标,该制导方法能够有效地去除抖振,并且具有良好的制导精度。针对导弹拦截高机动性目标的问题,基于自适应模糊逼近策略和动态面滑模控制思想,提出了一种新型的拦截制导律。建立了考虑自动驾驶仪动态延迟特性的弹目相对运动方程,以零化视线角速率为出发点,设计了基于自适应趋近率的动态面滑模制导律,同时设计了综合视线角速率以及弹目距离的自适应模糊方法,对变结构项进行逼近。仿真结果表明,针对高机动性目标,该制导方法能够有效地去除抖振,并且具有良好的制导精度。     

控制量受限情况下的有限时间收敛制导律

针对动能拦截器拦截临近空间高速机动目标的问题,基于零化视线角速率原理,应用有限时间收敛理论推导出了控制量受限情况下的Bang-Bang型滑模制导律有限时间收敛条件,既适用于二维平面情况又适用于三维空间问题。通过设计制导律中滞环控制开关门限的上下限,在视线角速率可控的条件下去除了其抖振。仿真结果表明,制导律有限时间收敛,具有较高的制导精度,并对目标机动具有鲁棒性。     

带有落角约束的间接Gauss伪谱最优制导律

针对带有落角约束的末制导问题,提出了一种基于极小值原理和Gauss伪谱法的最优制导律。以期望落角方向为坐标轴定义了落角坐标系,并在其中建立了线性化的导引运动关系方程。将控制系统简化为1阶惯性环节,利用极小值原理得到正则方程,然后引入Gauss伪谱法进行离散,将其转化为代数方程,结合边界条件,推导出最优制导律的解析表达式,无需任何积分过程,避免了求解黎卡提微分方程。仿真结果表明,所提出的算法运算量小,计算效率高,同时也能方便地求解出复杂加权矩阵下的最优制导律,能够在满足落角约束的条件下更快地收敛到落角参考线,并且具有更小的末端需用过载。     

考虑导弹速度变化的攻击时间和攻击角度控制滑模制导律

为了解决导弹速度变化时对攻击时间和攻击角度的控制问题,提出了一种基于成型理论和非奇异终端滑模理论的攻击时间和攻击角度控制制导律,并证明了该制导律的Lyapunov稳定性。以弹目相对运动关系为基础,将导弹速度变化的制导律问题转化为导弹速度恒定的制导律问题。利用成型理论构造视线角多项式,通过数值方法计算其系数,得到了满足攻击时间和攻击角度约束的理想视线角表达式。基于非奇异终端滑模理论设计了导弹法向加速度,使导弹实际视线角按照理想视线角变化,实现了攻击时间和攻击角度控制。不同条件下的数值仿真结果验证了所设计制导律的有效性。     

带角度约束的倾斜转弯飞行器制导律设计

针对倾斜转弯飞行器以给定角度攻击目标的要求,考虑控制回路动态特性对制导的影响,研究了带角度约束的制导律设计方法。以倾侧角和法向过载指令为控制量,建立了含控制回路动态特性的设计模型; 基于该模型和多通道解耦的思想,提出带角度约束的滑模变结构制导律,通过调整趋近律参数消除抖振。理论分析表明:在初始阶段,该制导律较最优制导律对过载的需求小; 通过优化制导律参数,当系统进入滑模面后,飞行器能按最优制导律命中目标。仿真表明,该制导律在满足落点和落角要求的同时,具有对过载需求分配合理、速度损失小的优点。     

考虑自动驾驶仪动态特性和攻击角约束的鲁棒末制导律

针对制导弹箭打击机动目标时带攻击角约束的末制导问题,考虑自动驾驶仪动态特性以及目标机动不确定性对制导过程的影响,结合积分滑模与动态面控制方法,设计了一种新型鲁棒末制导律。自动驾驶仪的动态特性以含扰动的2阶动力学模型来表征,目标机动引起的模型不确定性以光滑非线性扰动观测器来估计。滑模面取视线角速率与视线角偏差的组合形式,且引入剩余飞行时间,以使制导弹箭在整个末制导过程中过载性能良好。依据李雅普诺夫稳定性理论证明了闭环系统中视线角速率与视线角偏差均最终一致有界任意小。通过数值仿真与弹道成型制导律及非奇异滑模制导律进行了对比,验证了该末制导律的有效性与优越性。     

基于模糊变系数策略的迎击拦截变结构制导律设计

迎击拦截是拦截问题中常见的一种制导方式。为提高拦截器的末制导精度,基于变结构控制设计零化视线角速率的变结构制导律是一种典型方法。对高速目标的迎击拦截出现相对速度过大,目标机动能力引起的导引初段需用过载过大的问题,应用模糊控制设计制导律的导航项及变结构项系数随剩余导引时间变化的策略以延长系统进入滑模面的时间,使系统进入滑模面的同时有效减小末制导初段的控制量。建模及仿真结果显示,该制导律在使视线角速率收敛的同时显著地减小了导引初段的需用过载,验证了该方法的有效性及对传统比例导引律的优越性。