Multiconstraint adaptive three-dimensional guidance law using convex optimization

The traditional guidance law only guarantees the accuracy of attacking a target. However, the look angle and acceleration constraints are indispensable in applications. A new adaptive three-dimensional proportional navigation(PN) guidance law is proposed based on convex optimization. Decomposition of the three-dimensional space is carried out to establish threedimensional kinematic engagements. The constraints and the performance index are disposed by using the convex optimization method. PN guidance gains can be obtained by solving the optimization problem. This solution is more rapid and programmatic than the traditional method and provides a foundation for future online guidance methods, which is of great value for engineering applications.

Adaptive Sliding-Mode Control of an Automotive Electronic Throttle in the Presence of Input Saturation Constraint

In modern vehicles, electronic throttle(ET) has been widely utilized to control the airflow into gasoline engine. To solve the control difficulties with an ET, such as strong nonlinearity,unknown model parameters and input saturation constraints,an adaptive sliding-mode tracking control strategy for an ET is presented. Compared with the existing control strategies for an ET, input saturation constraints and parameter uncertainties are adequately considered in the proposed control strategy. At first, the nonlinear dynamic model for control of an ET is described. According to the dynamical model, the nonlinear adaptive sliding-mode tracking control method is presented,where parameter adaptive laws and auxiliary design system are employed. Parameter adaptive law is given to estimate the unknown parameter with an ET. An auxiliary system is designed,and its state is utilized in the tracking control method to handle the input saturation. Stability proof and analysis of the adaptive sliding-mode control method is performed by using Lyapunov stability theory. Finally, the reliability and feasibility of the proposed control strategy are evaluated by computer simulation.Simulation research shows that the proposed sliding-mode control strategy can provide good control performance for an ET.

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.

Three-dimensional guidance law based on adaptive integral sliding mode control

For the terminal guidance problem of missiles intercepting maneuvering targets in the three-dimensional space, the design of guidance laws for non-decoupling three-dimensional engage- ment geometry is studied. Firstly, by introducing a finite time integral sliding mode manifold, a novel guidance law based on the integral sliding mode control is presented with the target acceler- ation as a known bounded external disturbance. Then, an improved adaptive guidance law based on the integral sliding mode control without the information of the upper bound on the target accel- eration is developed, where the upper bound of the target acceleration is estimated online by a designed adaptive law. The both presented guidance laws can make sure that the elevation angular rate of the line-of-sight and the azimuth angular rate of the line-of-sight converge to zero in finite time. In the end, the results of the guidance performance for the proposed guidance laws are pre- sented by numerical simulations. Although the designed guidance laws are developed for the con- stant speed missiles, the simulation results for the time-varying speed missiles are also shown to further confirm the designed guidance laws.

Three-dimensional adaptive finite-time guidance law for intercepting maneuvering targets

To intercept maneuvering targets at desired impact angles, a three-dimensional terminal guidance problem is investigated in this study. Because of a short terminal guidance time, a finitetime impact angle control guidance law is developed using the fast nonsingular terminal sliding mode control theory. However, the guidance law requires the upper bound of lumped uncertainty including target acceleration, which may not be accurately obtained. Therefore, by adopting a novel reaching law, an adaptive sliding mode guidance law is provided to release the drawback. At the same time, this method can accelerate the convergence rate and weaken the chattering phenomenon to a certain extent. In addition, another novel adaptive guidance law is also derived; this ensures systems asymptotic and finite-time stability without the knowledge of perturbations bounds.Numerical simulations have demonstrated that all the three guidance laws have effective performances and outperform the traditional terminal guidance laws.

An Adaptive Weighted Differential Game Guidance Law

For intercepting modern high maneuverable targets, a novel adaptive weighted differential game guidance law based on the game theory of mixed strategy is proposed, combining two guidance laws which are derived from the perfect and imperfect in- formation pattern, respectively. The weights vary according to the estimated error of the target＇s acceleration, the guidance law is generated by directly using the estimation of target＇s acceleration when the estimated error is small, and a differential game guidance law with adaptive penalty coefficient is implemented when the estimated error is large. The adaptive penalty coeffi- cients are not constants and they can be adjusted with current target maneuverability. The superior homing performance of the new guidance law is verified by computer simulations.

Optimal predictive sliding-mode guidance law for intercepting near-space hypersonic maneuvering target

The design of optimal guidance law for intercepting a near-space hypersonic maneuvering target with bounded inputs is considered. Firstly, a maneuvering model for near-space hypersonic aircraft is given. Then, the aircraft acceleration prediction can be obtained using this model with two neural networks. By using the target acceleration prediction, which is taken into account when calculating the Zero Effort Miss(ZEM), an optimal sliding-mode guidance law is proposed to fulfill the guidance task. An adaptive sliding-mode switch term is designed to deal with actuator saturation and prediction errors. Finally, numerical simulations show that the proposed guidance law can reduce the energy consumption and the terminal acceleration command of the interceptor effectively.

基于PSO-AOGL的无人机航迹跟踪优化方法研究

精准的航迹跟踪是无人机实现任务规划的必要条件。针对自适应优化制导律(AOGL)算法中,权重矩阵依靠先验知识或者试探选取、缺乏理论指导且未必最优的问题,提出了一种基于粒子群优化AOGL航迹跟踪方法。将权重矩阵中各元素经验值乘以待优化系数,代入黎卡提方程,推导出修正之后的制导律,进而构造目标函数进行寻优求解。在不同的扰动风速条件下,针对线性、圆形期望跟踪航迹分别进行数值仿真,结果表明,PSO-AOGL航迹跟踪效果更优,可有效降低跟踪位置误差。

考虑攻击时间及空间角度约束的三维自适应滑模协同制导律设计

面向三维场景下的多导弹协同攻击机动目标问题,基于固定时间稳定理论和自适应滑模控制理论,设计考虑时间及空间约束的分布式协同制导律。在弹目视线方向上,基于固定时间一致性理论提出一种改进型自适应鲁棒协同制导律,驱动弹群以期望的攻击时刻协同拦截机动目标,并避免滑模固有的抖振问题;考虑视线法向的空间约束,基于固定时间非奇异终端滑模控制理论设计一种鲁棒自适应滑模制导律,在实现终端碰撞角约束的同时避免弹群间碰撞。通过Lyapunov稳定性理论证明闭环系统的固定时间稳定性。仿真结果表明:所设计三维协同制导律可以有效控制多发导弹在期望攻击时刻同时打击机动目标,并以期望的终端角度攻击目标。

基于改进非线性制导律的无人机航迹跟踪算法研究

针对固定翼无人机在侧风条件下的二维航迹跟踪问题,在非线性制导律的基础上,提出一种自适应引导长度的航迹跟踪算法。首先建立了引入风扰后的无人机运动学模型,对定引导长度的非线性制导律进行理论分析,并讨论了其抗风性能;然后结合无人机自身性能和飞行速度,提出自适应引导长度的方法,并在侧向加速度指令中引入侧偏距积分以抵消侧风干扰,同时针对无人机在航点切换时航迹误差偏大的问题,设计了一种圆弧航点切换策略;最后在侧风干扰的情况下进行数值仿真,结果表明,该方法能有效抑制侧风干扰,在航点切换处具有较高的跟踪精度,实现了固定翼无人机在侧风扰动条件下对期望航迹的精确跟踪。

一种考虑自动驾驶仪动态特性的自适应变结构制导律

对于平面拦截问题 ,提出了一种新的具有强鲁棒性的末端导引规律。将目标的机动加速度视为一类有界扰动 ,以视线角速率作为零输出状态变量 ,考虑导弹自动驾驶仪动态特性 ,应用滑模趋近律概念 ,综合设计了一种自适应变结构制导律。理论分析与数字仿真表明这种制导律不但具有优良的弹道特性 ,而且具有很强的鲁棒性和适应性 ,同时方法简单、易于理解 ,便于工程应用。

基于零脱靶量设计的变结构末制导律

对于三维目标拦截问题,提出了一种新的具有强鲁棒性的末端导引律。该方法将目标的机动加速度视为已知的有界扰动,考虑了导弹自动驾驶仪的动态特性,基于导弹对目标的零脱靶量综合设计了非线性三维变结构鲁棒末制导律。理论分析与数字仿真表明这种制导律不但具有优良的弹道特性,而且对目标机动都具有很强的鲁棒性和适应性,同时方法简单,易于理解,便于工程应用。

一种自适应变结构制导律

为了使导弹制导系统具备良好的鲁棒性，本文提出用滑模变结构控制理论设计末端导引规律。结合时变系统的特点，本文提出并应用了滑模自适应趋近律这一概念。理论分析和数字仿真表明自适应变结构制导律具有优良的弹道性能和鲁棒性。另外，此制导律比较简单。

非线性变结构制导律

为使导弹制导系统具有良好的鲁棒性能和适应性能,本文基于Lyapunov稳定性理论,利用滑模控制来设计导弹的末端导引规律。考虑结构摄动和目标机动加速度的界未知情况下,提出了一种基于零化视线法向速度的具有强鲁棒性的末端导引规律,这种制导律在保证系统闭环稳定的前提下能够在线对结构摄动和目标机动加速度的界进行估计。仿真验证说明所提出的方法是有效的。

三维非线性变结构寻的制导律

建立了球坐标系内的三维导弹与目标相对运动模型,基于零化导弹与目标的视线角速度设计了非线性三维变结构鲁棒末制导律。该制导律考虑了更一般的拦截情况,不依赖于碰撞线附近线性化的假设,克服了剩余时间的估计误差对制导精度的不利影响。仿真结果表明,该制导律对于目标做复杂的大机动逃逸运动,仍然能够取得较好的脱靶量。

一种打击地面固定目标的自适应比例导引律

针对某些制导导弹垂直打击地面固定目标的任务要求,研究了具有末端落角约束且无需测距信息的自适应比例导引律。通过分析导弹在导引段的纵向平面运动方程和侧向平面运动方程的特点,设计了实现垂直打击任务的制导逻辑。同时为了增强导引律的鲁棒性,提出了一种导引系数自适应更新的方案。仿真结果表明,与最优导引律相比,自适应比例导引律的制导精度受初始速度倾角、制导指令时延、制导指令更新频率等因素的影响较小,但受测量信号干扰的影响较大。

变结构自适应制导规律研究

由于变结构控制的滑动模态具有完全的自适应 ,不必全面研究系统的各种摄动及外干扰 ,而只需要根据高速度大机动目标的特点 :一个是机动 ,一个是高速 (包括速度变化 ) ,对两者实现自适应 ,把各种干扰及偏差的影响归入有关增益系数上加以考虑 ,在选择增益系数上进行了深入的研究。应用变结构自适应控制理论 ,推导出一种适用于导弹拦截高速度大机动运动目标的空间制导规律 ,该制导规律能将系统引向滑动面 ,并保持在滑动面上运动。因此将它应用于导弹跟踪标准优化弹道 ,经导弹拦截目标弹道数字仿真 ,取得了良好的结果。

基于自适应动态规划的导弹制导律研究综述

自适应动态规划(Adaptive dynamic programming,ADP)作为最优控制领域的近似优化方法,是求解复杂非线性系统最优控制问题的有力工具.近年来,已成为控制理论与计算智能领域的研究热点.本文着重介绍ADP算法的理论研究进展及其在航空航天领域的应用.分析了几种典型的制导律优化设计方法,以及ADP方法在导弹制导律设计中的应用现状和前景.

变论域模糊自适应滑模有限时间收敛制导律

针对拦截高速机动目标的需求,研究了一种变论域模糊自适应滑模有限时间收敛制导律。推导了导弹-目标空间拦截模型,设计了三维滑模制导律;根据有限时间收敛制导律专家的经验,采用模糊自适应控制方法对滑模制导律的非切换项进行逼近,并设计了有限时间收敛模糊控制规则;提出了一种新型变论域伸缩因子,设计了基于新型伸缩因子的变论域模糊自适应滑模有限时间收敛制导律。仿真结果表明,所设计的制导律能够使导弹准确命中目标,并能够达到视线角速率有限时间收敛,且与比例制导律相比,具有更高的制导精度和更短的飞行时间。

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。