具有持续扰动的时滞系统的最优跟踪控制

针对在外部持续扰动下的线性时滞系统提出了一种最优跟踪控制的逐次逼近算法。首先将状态向量含有时滞的线性系统的最优跟踪问题转化为最优调节问题，然后利用逐次逼近算法，将既含有时滞项又含有超前项的两点边值问题转化为不含时滞项和超前项的线性两点边值问题族得到调节系统的最优控制律，然后可以通过截取最优控制序列的有限项得到调节系统的前馈-反馈次优控制律，最后再将最优控制问题转化为最优跟踪问题。     

受扰非线性时滞系统的最优跟踪控制

考虑受扰非线性时滞系统的最优跟踪控制问题.基于内模原理构造扰动补偿器,将受扰系统转化成无扰动的增广系统.通过引入灵敏度参数并围绕其进行Maclaurin级数展开,将原时滞非线性系统的最优跟踪控制问题转化为无时滞的两点边值问题.通过求解增广系统的最优跟踪控制律从而得到原系统的最优跟踪控制律.仿真实例表明该方法的有效性.     

基于线性近似和神经网络逼近的模型预测控制

针对非线性系统的模型预测控制问题,提出了一种基于线性近似和神经网络逼近的控制算法。用Taylor级数展开法对非线性系统进行线性近似时,要求对象系统中的非线性函数必须连续可微。为了突破这一限制,引入了Stirling插值公式线性近似法,拓展了可处理的非线性系统范围。通过对线性化过程中产生的非线性高阶项进行径向基函数(radial basis function, RBF)神经网络逼近,显著提高了对象系统模型精确度。为了降低数值计算复杂度,将控制性能指标函数重构为易于处理的二次型最优化问题,通过对该二次型最优化问题的求解得到了最优控制序列。控制过程考虑了约束条件的影响以模拟真实的工业生产过程。仿真结果证明了所提出预测控制方案的有效性。     

带有持续扰动非线性系统的最优跟踪控制

研究具有外界持续扰动的非线性系统的无静差最优跟踪控制问题。首先基于内模原理构造一扰动补偿器,将系统化为无扰动的增广系统。然后利用灵敏度法推导出了该系统的最优跟踪控制律。仿真实例表明了该设计方法的有效性。     

一种基于参数扰动退火策略的神经网络全局优化新算法

针对非线性全局优化问题,提出了一种新算法它采用参数扰动策略,使Hopfield神经网络克服局部极值点的吸引,同时对参数扰动采用模拟退火算法,使扰动逐渐减小,直到扰动不能对最优解和最优值产生影响,从而得到全局最优解.通过对大量测试函数的仿真计算,充分体现了新算法在速度、精度和适应性方面的优势.本文还对算法的收剑性进行了理论分析.     

带有持续扰动的线性系统的前馈-反馈最优控制

研究具有已知动态特性但未知初始条件的持续外界扰动作用下线性系统的前馈-反馈最优控制问题。利用求解Riccati方程和矩阵方程推导出前馈．反馈最优控制律。给出了前馈-反馈最优控制律的存在唯一性条件，并提出了最优控制律的实现算法。仿真结果表明，该方法易于实现且抑制外部持续扰动的鲁棒性优于经典反馈最优控制。     

自由漂浮空间机器人载体姿态扰动最优轨迹规划

针对机械臂运动产生的航天器载体姿态扰动,提出一种基于粒子群优化算法的自由漂浮空间机器人载体姿态扰动最优轨迹规划方案。对系统角动量守恒方程进行分析,给出了载体姿态扰动最优轨迹规划的目标函数。采用高阶多项式逼近机械臂关节角轨迹,将多项式系数作为优化参数。为保证规划算法的收敛性,采用带有收缩因子的粒子群优化算法进行轨迹寻优。仿真结果表明,在完成位姿调整任务的同时,载体姿态扰动得到了有效的抑制,验证了所提方法的有效性。     

一类非线性广义系统最优控制及应用

利用Zubov方法和最优控制理论研究了非线性广义系统的最优控制问题.首先将非线性广义系统正则化为非线性正常系统,对其施加状态反馈控制,继而构造含有调节参数向量的性能指标,并由偏微分方程解得该性能指标;最后应用最优化理论求得最优调节参数向量,得到非线性广义系统最优控制律.将有关结论应用于Logistic 增长的SIS模型,给出消除该传染病的条件.     

利用引信多普勒频率估计导弹脱靶量方法研究

针对利用导弹引信多普勒频率数据求取脱靶量的问题,提出了一种非线性最小二乘优化参数估计方法。该方法利用导弹遥测数据独立获取引信多普勒频率数据,因而在无须对测量系统作任何改进的情况下,可得到导弹脱靶量的最优估计。通过对污染数据的野点剔除、补点和逐次逼近,有效地提高了脱靶量的估计精度。给出了应用该方法的具体步骤,通过模拟和实际数据计算证明了该方法的有效性。     

基于反馈线性化H∞理论的风电系统桨距角控制

风电系统工作在额定风速以上时,扰动风速会导致输出功率出现脉动,这会对电网的稳定性产生不利影响.为了解决这个实际问题,将非线性干扰抑制理论应用到桨距角控制律的设计中,建立了整个机组合风速扰动项的非线性数学模型;采用精确线性化方法将问题转化为标准的H∞控制问题,以避免HJI不等式的求解,同时还可以保证系统在工况点大范围变动时仍具有较好的控制性能.利用MATLAB/Simulink进行了对比仿真,结果表明该控制策略对风速扰动具有抑制作用,能够实现功率的平稳输出,适应工况点大范围变动的情形,控制性能要优于基于单个工况点近似线性化模型的控制方法.     

Optimal tracking control for linear time-delay large-scale systems with persistent disturbances

An optimal tracking control (OTC) problem for linear time-delay large-scale systems affected by external persistent disturbances is investigated. Based on the internal model principle, a disturbance compensator is constructed. The system with persistent disturbances is transformed into an augmented system without persistent disturbances. The original OTC problem of linear time-delay system is transformed into a sequence of linear twopoint boundary value (TPBV) problems by introducing a sensitivity parameter and expanding Maclaurin series around it. By solving an OTC law of the augmented system, the OTC law of the original system is obtained. A numerical simulation is provided to illustrate the effectiveness of the proposed method.     

Feedforward and feedback optimal control for linear time-varying systems with persistent disturbances

1 .INTRODUCTIONIn nature ,there are various external disturbancesaffecting the performances of systems . Many con-trol problemsinvolve designing a controller capableof stabilizing a given linear system while mini mi-zing the worst-case response to some additive dis-turbances . This problemis relevant to disturbancerejection and cancellation. One application area ofinterest is flight control through wind shear ,where disturbances arise from a modal for windshear based on harmonic oscillati…     

Robust fault diagnosis with disturbance rejection and attenuation for systems with multiple disturbances

The fault diagnosis problem is investigated for a class of nonlinear neutral systems with multiple disturbances.Time-varying faults are considered and multiple disturbances are supposed to include the unknown disturbance modeled by an exo-system and norm bounded uncertain disturbance.A nonlinear disturbance observer is designed to estimate the modeled disturbance.Then,the fault diagnosis observer is constructed by integrating disturbance observer with disturbance attenuation and rejection performances.The augmented Lyapunov functional approach,which involves the tuning parameter and slack variable,is applied to make the solution of inequality more flexible.Finally,applications for a two-link robotic manipulator system are given to show the efficiency of the proposed approach.     

Global Disturbance Rejection of Switched Nonlinear Systems with Switched Internal Model

This paper investigates the problem of global disturbance rejection for a class of switched nonlinear systems where the solvability of the disturbance rejection problem for subsystems is not assumed. The disturbances are assumed to be sinusoidal with completely unknown frequencies, phases and amplitudes. First, as an extension of the classic concept of internal model for non-switched systems, a switched internal model is proposed. Second, in order to solve the problem under study, an adaptive control method is established on the basis of the multiple Lyapunov functions method. Also, adaptive state-feedback controllers of subsystems are designed and incorporated with a switching law to asymptotically reject the unknown disturbances. Finally, an example is provided to demonstrate the effectiveness of the proposed design method.     

Non-fragile guaranteed cost control for uncertain neutral large-scale interconnected systems

This paper focuses on the problem of non-fragile decentralized guaranteed cost control for uncertain neutral large-scale interconnected systems with time-varying delays in state, control input and interconnections. A novel scheme, viewing the interconnections with time-varying delays as effective information but not disturbances, is developed. Based on Lyapunov stability theory, using various techniques of decomposing and magnifying matrices, a design method of the non-fragile decentralized guaranteed cost controller for unperturbed neutral large-scale interconnected systems is proposed and the guaranteed cost is presented. The further results are derived for the uncertain case from the criterion of unperturbed neutral large-scale interconnected systems. Finally, an illustrative example shows that the results are significantly better than the existing results in the literatures.     

Asymptotic controllability of a class of discrete-time systems with disturbances

This article deals with the uniformly globally asymptotic controllability of discrete nonlinear systems with disturbances. It is shown that the system is uniformly globally asymptotic controllability with respect to a closed set if and only if there exists a smooth control Lyapunov function. Further, it is obtained that the control Lyapunov function may be used to construct a feedback law to stabilize the closed-loop system. In addition, it is proved that for periodic discrete systems, the resulted control Lyapunov functions are also time periodic.     

Optimal deterministic disturbances rejection for singularly perturbed linear systems

1. INTRODUCTION It is well known that external disturbances exist in almost all practical systems, such as wind or ocean wave forces in active control systems for offshore structures[1], harmonic oscillations in flight control systems through wind shear[2] , and periodic disturb- ance in the disk drive[3]. In recent years, various reliable approaches with regard to the disturbance rejection and cancellation have been well documented in many literatures. Lee et al. [4] proposed the model-ba…