Backstepping design of missile guidance and control based on adaptive fuzzy sliding mode control

This paper presents an integrated missile guidance and control law based on adaptive fuzzy sliding mode control. The integrated model is formulated as a block-strict-feedback nonlinear system, in which modeling errors, unmodeled nonlinearities, target maneuvers, etc. are viewed as unknown uncertainties. The adaptive nonlinear control law is designed based on backstepping and sliding mode control techniques. An adaptive fuzzy system is adopted to approximate the coupling nonlinear functions of the system, and for the uncertainties, we utilize an online-adaptive control law to estimate the unknown parameters. The stability analysis of the closed-loop system is also conducted. Simulation results show that, with the application of the adaptive fuzzy sliding mode control, small miss distances and smooth missile trajectories are achieved, and the system is robust against system uncertainties and external disturbances.     

Dynamic modeling of a hose-drogue aerial refueling system and integral sliding mode backstepping control for the hose whipping phenomenon

Dynamic modeling of a hose-drogue aerial refueling system（HDARS） and an integral sliding mode backstepping controller design for the hose whipping phenomenon（HWP） during probe-drogue coupling are studied. Firstly, a dynamic model of the variable-length hose-drogue assembly is built for the sake of exploiting suppression methods for the whipping phenomenon.Based on the lumped parameter method, the hose is modeled by a series of variable-length links connected with frictionless joints. A set of iterative equations of the hose＇s three-dimensional motion is derived subject to hose reeling in/out, tanker motion, gravity, and aerodynamic loads accounting for the effects of steady wind, atmospheric turbulence, and tanker wake. Secondly,relying on a permanent magnet synchronous motor and high-precision position sensors, a new active control strategy for the HWP on the basis of the relative position between the tanker and the receiver is proposed. Considering the strict-feedback configuration of the permanent magnet synchronous motor, a rotor position control law based on the backstepping method is designed to insure global stability. An integral of the rotor position error and an exponential sliding mode reaching law of the current errors are applied to enhance control accuracy and robustness. Finally,the simulation results show the effectiveness of the proposed model and control laws.     

Finite-time sliding mode attitude control for a reentry vehicle with blended aerodynamic surfaces and a reaction control system

This paper proposes a finite-time robust flight controller, targeting for a reentry vehicle with blended aerodynamic surfaces and a reaction control system(RCS). Firstly, a novel finite-time attitude controller is pointed out with the introduction of a nonsingular finite-time sliding mode manifold. The attitude tracking errors are mathematically proved to converge to zero within finite time which can be estimated. In order to improve the performance, a second-order finite-time sliding mode controller is further developed to effectively alleviate chattering without any deterioration of robustness and accuracy. Moreover, an optimization control allocation algorithm, using linear programming and a pulse-width pulse-frequency(PWPF) modulator, is designed to allocate torque commands for all the aerodynamic surface deflections and on–off switching-states of RCS thrusters.Simulations are provided for the reentry vehicle considering uncertain parameters and external disturbances for practical purposes, and the results demonstrate the effectiveness and robustness of the attitude control system.     

一种基于滑模非奇异的反舰导弹导引律的设计与仿真

提出了一种反舰导弹滑模非奇异导引律。根据反舰导弹弹道的运动学分析方法,建立了弹目相对运动的数学模型。在非奇异理论的基础上,推导出具有带落角约束的滑模非奇异导引律。通过仿真,表明了该导引律能同时满足脱靶和落角的性能指标,具有优良的鲁棒性,脱靶量更小,精度更高。相比传统的比例导引律,具有更强的实用性和有效性。     

基于高斯过程的航天器自适应滑模姿态控制

针对存在模型不确定性和外界干扰的刚性航天器,提出了一种基于高斯过程回归(GPR)的新型自适应滑模姿态控制算法。该算法具有自学习能力,在不同的姿态控制任务下都能够实现高精度、强鲁棒和高效率的姿态跟踪。首先,在航天器的四元数标称系统动态模型基础上,应用在线稀疏高斯过程回归(SOGP)方法学习系统的未知动态;其次,结合高斯过程的预测均值设计滑模控制算法,利用高斯过程的预测方差自适应调节控制增益,并应用李雅普诺夫方法严格证明闭环系统的稳定性,保证了航天器姿态跟踪误差的渐进收敛性;最后,通过数值仿真验证了所设计控制器的有效性。结果表明,该自学习控制算法与自适应滑模控制(ASMC)与神经网络自适应控制等算法相比,具有更快的收敛速度、更高的跟踪精度以及更低的控制成本。     

半球谐振陀螺仪谐振子品质因数不均匀引起的误差分析

 半球谐振子的品质因数不均匀性是造成陀螺仪输出误差的一个主要误差源,所以研究在参数激励以及位置激励两种模式下,谐振子品质因数不均匀对于陀螺仪输出误差的影响具有一定的理论意义。在引入半球谐振子的环形振动模型的基础上,首先考虑参数激励方式下,品质因数不均匀引起的进动角速率误差的表达式,仿真分析了不均匀性四次谐波对陀螺仪漂移角度的贡献,结果表明漂移角度为具有趋势项的振动曲线。然后在位置激励方式下,通过开环和闭环两种模式分别研究了品质因数不均匀的四次谐波对于输入角速率解算的影响,得出了当位置激励对准固有韧性轴时,解算的误差能够得到抑制的结论。总之,在两种激励方式下,品质因数的四次谐波分量都会导致陀螺仪出现输出误差。     

大展弦比飞机模型边界层转捩模拟技术

针对大展弦比飞机模型高速风洞试验需求,进行了边界层转捩模拟技术研究.研究表明:与传统的金刚砂粗糙带相比,柱状转捩带具有粘贴牢靠、可操作性强等优势,已经推广应用于大展弦比飞机模型高速风洞试验;边界层转捩对大展弦比飞机模型气动特性有重要影响,不仅影响阻力,而且对升力与俯仰力矩均有明显影响;在目前国内低雷诺数风洞条件下建议在边界层固定转捩条件下进行风洞试验,以提高风洞试验精度.     

低雷诺数下翼型层流分离泡及吹吸气控制数值研究

在低雷诺数下Eppler387翼型表面会出现层流分离泡现象,因此本文使用Fluent求解器开展吹/吸气控制翼型表面层流分离泡的数值研究,主要探究了射流位置、射流角度、射流速度比三个控制参数对层流分离泡控制的影响规律.研究结果表明,采用与SSTκ-ω湍流模型耦合的γ～(Reθt)转捩模型可以准确预测层流分离泡的位置;吹/吸气可以有效抑制低雷诺数下层流分离泡的发展,明显提高低雷诺数下翼型升阻比.固定射流位置,较大吸气速度比和较小吹气速度比可分别获得较好的流动控制效果,且吸气控制比吹气控制对层流分离泡的抑制作用更加有效.     

低压涡轮叶栅流动中转捩模型的校验及改进

为评估并提高现有转捩模型的预测精度,采用计算流体力学(CFD)软件FLUENT 12.1,选取层流模型、全湍流模型、剪切应力输运(SST)低雷诺数模型、k-kl-ω模型以及γ-Reθ模型对低压涡轮叶栅T106-EIZ进行数值模拟,通过与实验数据的对比校验了后3种模型对于转捩以及相关参数的模拟能力,并对结果以及模型的作用机理进行分析,校验结果表明所有模型都不能准确地预测分离流转捩以及尾迹诱导转捩.选取预测效果较好的γ-Reθ模型进行了修正,提出通过修改间歇因子输运方程中的参数Ca1和Ca2的方法来修正该模型,结果表明该方法可以提高模拟精度.     

基于遗传算法的凸多边形区域航迹规划

提出了基于遗传算法的凸多边形区域航迹规划方法,针对飞行器转弯角和边界限制的航迹约束条件,改进了航迹编码方式,采用了基于方向编码的回溯方法生成航迹;同时改进了遗传算法的交叉算子和变异算子。仿真结果表明,该方法能快速有效地完成飞行器航迹规划任务,获得符合适应度要求的优化航迹。