Fractional-order sliding mode load following control via disturbance observer for modular high-temperature gas-cooled reactor system with disturbances

Load-following control of the modular high-temperature gas-cooled reactor (MHTGR) system is one of the essential control problems in practical applications. In this paper, a fractional-order sliding mode control strategy via a disturbance observer (FOSMCS-DO) is presented for load following of the MHTGR system with model uncertainties and external disturbances. First of all, the mathematical model of the MHTGR system is constructed by taking neutronics and thermodynamics as well as disturbances into account. Then, based on the MHTGR model, a DO is designed to estimate the lumped disturbances that are composed of model uncertainties, external disturbances, and unmeasured states. Meanwhile, by adopting the Lyapunov stability theory, a FOSMCS is developed to guarantee all the signals of the closed-loop load-following control system tend to be stable, where in the control framework, the adverse effects of the lumped disturbances are alleviated by means of the feedforward compensation and the DO. This implies that the proposed overall control strategy possesses strong robustness against model uncertainties and external disturbances. Finally, comparative simulation results with some existing control approaches are provided to illustrate the superiority of the proposed control strategy.     

导弹鲁棒分数阶PID自动驾驶仪设计

由于分数阶PID继承了传统PID的优点,并且具有更好的控制品质及更强的鲁棒性,因此针对导弹飞行过程中变参数、受环境干扰及快速稳定的特点,设计了鲁棒分数阶PID自动驾驶仪.基于最优Oustaloup数字算法建立框图式分数阶控制系统模型,结合IAE时域性能指标寻优及鲁棒性能量度,综合考虑时域性能及频域性能来整定分数阶PID...     

Adaptive Containment Control for Fractional-Order Nonlinear Multi-Agent Systems With Time-Varying Parameters

This paper investigates adaptive containment control for a class of fractional-order multi-agent systems (FOMASs) with time-varying parameters and disturbances. By using the bounded estimation method, the difficulty generated by the time-varying parameters and disturbances is overcome. The command filter is introduced to solve the complexity problem inherent in adaptive backstepping control. Meanwhile, in order to eliminate the effect of filter errors, a novel distributed error compensating scheme is constructed, in which only the local information from the neighbor agents is utilized. Then, a distributed adaptive containment control scheme for FOMASs is developed based on backstepping to guarantee that the outputs of all the followers are steered to the convex hull spanned by the leaders. Based on the extension of Barbalat’s lemma to fractional-order integrals, it can be proven that the containment errors and the compensating signals have asymptotic convergence. Finally, three simulation examples are given to show the feasibility and effectiveness of the proposed control method.      

时滞系统分数阶PI?? 极点配置控制器设计

利用参数空间法研究用PIλ控制器实现时滞系统的闭环极点配置问题。复平面上的阻尼角扇形区域和相对稳定度区域(该两区域构成一个梯形区域)被映射到控制器参数平面,相应的控制器参数可以将闭环极点配置在梯形区域内,从而保证所要求的系统性能。仿真结果显示,对于适当选取的分数阶PIλ控制器的参数,采用分数阶控制器可以取得比整数阶控制器更好的控制效果,从极点配置的角度揭示了分数阶控制器的优越性。     

基于自适应神经网络的分数阶混沌系统滑模同步

针对一类异结构不确定分数阶混沌系统的同步问题,基于Lyapunov稳定性理论和分数阶系统稳定性理论,提出一种神经网络结合干扰观测器的主动反馈控制方法. 设计一种非线性干扰观测器对干扰进行观测,通过滑模控制对未观测出的部分干扰进行补偿,最终实现分数阶混沌系统的同步.与现有方法相比,采用的模型更符合工程应用实际,且不需要已知不确定项上界.数值仿真验证了所提出方法的有效性和正确性.     

Decentralized Adaptive Strategies for Synchronization of Fractional-order Complex Networks

This paper focuses on synchronization of fractionalorder complex dynamical networks with decentralized adaptive coupling. Based on local information among neighboring nodes, two fractional-order decentralized adaptive strategies are designed to tune all or only a small fraction of the coupling gains respectively. By constructing quadratic Lyapunov functions and utilizing fractional inequality techniques, Mittag-Leffler function, and Laplace transform, two sufficient conditions are derived for reaching network synchronization by using the proposed adaptive laws. Finally, two numerical examples are given to verify the theoretical results.      

一类分数阶四维混沌系统及其投影同步

提出了一个新的四维自治类新混沌系统.首先在整数阶下分析了该系统的基本动力学特性.并利用数值仿真、功率谱分析了当参数固定时,分数阶新混沌系统随微分算子阶数变化时的动力学特性.研究表明:当微分算子阶数为0.85时,分数阶新系统随参数变化经短暂混沌和边界转折点分叉而进入混沌.针对一类结构部分未知分数阶混沌系统,基于Cheby...     

Coordination of fractional-order nonlinear multi-agent systems via distributed impulsive control

The coordination of fractional-order nonlinear multi-agent systems via distributed impulsive control method is studied in this paper. Based on the theory of impulsive differential equations, algebraic graph theory, Lyapunov stability theory and Mittag-Leffler function, two novel sufficient conditions for achieving the cooperative control of a class of fractional-order nonlinear multi-agent systems are derived. Finally, two numerical simulations are verified to illustrate the effectiveness and feasibility of the proposed method.     

分数阶随机Duffing系统的Hopf分岔

运用正交多项式逼近原理，研究了分数阶随机Duffing系统在零平衡点的Hopf分岔．首先，运用Laguerre正交多项式逼近法将含有随机参数的分数阶Duffing系统转化为等价的确定性系统，然后通过数值计算求得其响应．最后，利用两个引理求得等价系统发生Hopf分岔行为的临界值，并通过数值模拟验证了理论分析结果．     

Robust Stability Analysis of Smith Predictor Based Interval Fractional-Order Control Systems: A Case Study in Level Control Process

The robust stability study of the classic Smith predictor-based control system for uncertain fractional-order plants with interval time delays and interval coefficients is the emphasis of this work.Interval uncertainties are a type of parametric uncertainties that cannot be avoided when modeling real-world plants.Also,in the considered Smith predictor control structure it is supposed that the controller is a fractional-order proportional integral derivative(FOPID) controller.To the best of the a...