基于自适应神经模糊推理系统的船舶航向自抗扰控制

在实际的船舶航向控制中,航向系统在受到外界风浪干扰时表现出的模型非线性和参数不确定性,为航向控制器的设计带来了困难。针对该问题,设计了常规的线性自抗扰控制器和两种在线学习的自抗扰控制器。利用自适应神经模糊推理系统(ANFIS)实现自抗扰控制器参数的在线调整,设计了自适应PD的自抗扰控制器和自适应扩张状态观测器(ESO)的自抗扰控制器;分别在船舶受到外界扰动和参数摄动的两种情况下进行了仿真,仿真表明自适应自抗扰控制器控制效果更好,抗扰能力更强,表现出较强的鲁棒性。     

立方体机器人自抗扰平衡控制方法

针对立方体机器人动力学模型多变量、强耦合的问题,提出一种基于自抗扰控制的平衡控制器设计方法.引入虚拟控制量,并在控制量与输出向量之间并行地嵌入多个自抗扰控制器,从而实现对多变量系统的解耦控制,将系统的动态耦合和外部扰动视为各自通道上的自抗扰控制器的总扰动,在为期望姿态安排过渡过程基础上,设计扩张状态观测器对总扰动进行估计并实时补偿.综合采用经验试凑法和带宽法对控制器参数进行整定,对自抗扰控制器系统进行稳定控制、姿态跟踪、抗扰性和鲁棒性实验,并与PID控制系统进行定量对比分析.仿真结果表明,所设计的自抗扰控制器不仅能有效实现立方体机器人的平衡控制,而且较PID控制器具有更好的响应速度、控制精度和强鲁棒性.     

考虑有执行器故障和有界扰动的鲁棒自适应容错补偿控制

考虑在执行器故障和外界干扰下, 用直接自适应状态反馈控制策略解决线性时不变连续时间系统的鲁棒容错补偿控制问题. 提出更一般且更实际的执行器故障模型. 在执行器故障和扰动的上界都未知下, 提出自适应律在线估计未知控制器参数. 然后基于自适应策略的信息, 构造一类鲁棒自适应状态反馈控制器自动补偿故障和扰动的影响. 基于李亚普诺夫定理, 在执行器故障和干扰下, 所得的自适应闭环系统可以被保证渐进稳定. 最后给出一个火箭整流罩模型的例子和它的仿真结果.     

基于非线性干扰观测器的飞机全电刹车系统滑模控制设计

飞机防滑刹车具有典型的强非线性、强耦合和参数时变等特点, 并且跑道环境的干扰容易对飞机的地面滑跑性能造成不利影响. 本文提出了一种基于非线性干扰观测器的飞机全电防滑刹车系统滑模控制设计方法. 首先, 考虑了实际刹车不确定性干扰条件下的防滑刹车动力学建模问题, 通过对高阶非线性刹车系统进行反馈线性化处理, 简化了基于严格反馈的模型. 其次, 基于对主轮打滑原因的深入分析, 设计了非线性干扰观测器对干扰进行在线估计, 并在控制律设计中引入补偿部分. 通过构造递归结构的快速终端滑模控制器来跟踪实时变化的最佳滑移率并建立稳定性条件, 实现了飞机全电防滑刹车系统的有限时间快速稳定并有效抑制了主轮锁定打滑. 通过在不同跑道状态下进行模拟仿真, 验证了本文提出的飞机防滑刹车控制策略可以有效地提高刹车效率.     

并网逆变器逆系统自学习滑模抗扰控制

针对三相并网逆变器模型的多变量、非线性、强耦合等特点,采用开关函数法建立其开关周期平均模型,在此模型的基础上采用逆系统方法实现反馈线性化和解耦控制,对伪线性系统设计自适应滑模抗扰控制器,使用非线性光滑函数设计扩张状态观测器以实现内部建模误差与外部扰动的扩张状态估计,并将非线性扩张状态观测器和跟踪微分器与自学习滑模控制器结合使用.仿真结果表明,该方法具有响应速度快、控制精度高、抗扰能力强的特性,在并网逆变器中具有较大应用价值.     

线性自抗扰控制在全桥DC–DC变换器中的应用

针对DC–DC变换器在实际应用中会受到多种输入扰动、负载扰动及电磁扰动影响的问题,本文结合全桥DC–DC变换器的系统模型特点,对传统线性自抗扰控制器进行了改进.设计了基于降阶扩张状态观测器和以比例控制作为误差反馈律的自抗扰控制器用于实际系统,在确保系统性能的前提下优化了参数整定过程.仿真和实验结果表明,该控制系统具有比传统PI控制系统更优的快速性、鲁棒性和适应性,且大大简化了传统自抗扰控制器设计过程中参数过多、取值困难的问题,具有良好的发展前景.     

高阶不确定非线性系统的线性自抗扰控制

针对一类具有内部动态和外部扰动未知的SISO高阶非线性系统,提出一种通用的线性自抗扰控制方案.该方案基于单参数调节的高增益观测器思想,分别设计线性跟踪微分器、线性扩张状态观测器和线性状态误差反馈控制律.利用Lagrange中值定理和Cauchy-Schwarz不等式将系统总扰动的微分值转化为关于系统估计和跟踪误差的函数,可以解决因系统控制增益未知所导致的控制量微分值难以预先确定的问题.在此基础上,基于Lyapunov稳定性定理证明闭环系统误差信号有界,并进一步分析得到系统估计和跟踪误差与控制器参数的定量关系,即都可以随观测器增益的增大而达到无限小.仿真比较结果验证了所提出方案的有效性,与韩式自抗扰控制方案相比,该方案结构简单,调节参数少,易于工程实现.     

推力矢量可倾转四旋翼自抗扰飞行控制方法

针对常规四旋翼难以实现位置和姿态独立控制问题, 研究了一种具有全向推力矢量的可倾转四旋翼飞行 器系统. 为克服系统的大范围不确定性、强耦合性及外部风扰影响, 设计了基于自抗扰控制(ADRC)技术的飞行控 制器. 通过建立风扰下的系统动力学模型, 分析阵风对旋翼气动力的影响. 接着将系统解耦为六通道单回路结构并 分别设计自抗扰控制器, 引入扩张状态观测器估计系统的内外扰动, 利用非线性状态误差反馈律输出扰动补偿控 制. 在此基础上, 通过变量代换线性化控制分配矩阵, 将控制器输出直接映射到旋翼转速和倾转角. 仿真结果表明, 所设计的自抗扰飞行控制器具有良好的位置和姿态独立控制能力, 能够有效地估计和补偿紊流风扰动, 同时对系统 的部分动力失效故障有较强的鲁棒性.     

基于线性自抗扰的开关磁阻电机调速控制研究

开关磁阻电机调速系统是复杂的非线性时变系统,负载扰动大,变量之间耦合严重,针对上述系统的性能特点提出采用线性自抗扰控制策略对系统进行控制的方法。首先为克服负载扰动变化,电机磁链呈非线性以及电流、位置等参数耦合的内外部干扰问题,设计扩张状态观测器对系统内扰和外扰进行准确估计并实时补偿。然后设计PD（比例-微分）控制器抑制系统给定与扩张状态观测器反馈的观测对象状态变量之间的跟踪误差。最后在仿真平台上对设计的控制系统进行试验并与传统PID控制方案进行对比,结果显示,对于给定的阶跃信号线性自抗扰控制器只需0.09s即可达到稳态且无超调,而PID控制器需要3s才能实现稳定跟踪。因此相比于传统PID控制,线性自抗扰控制器拥有更优的动静态性能,并且系统在外部负载扰动和内部模型参数变化的情况下也有良好的控制效果,表现出了很好的鲁棒特性。     

线性自抗扰控制的适用性及整定

线性自抗扰控制将被控对象看成串级积分系统,把其他信息都当成不确定性.这种处理方法简单,但是对什么样的系统有效,目前还没有理论给出确定的答案.本文证明任何带有积分行为的严格正则传递函数都可以由线性自抗扰控制的反馈控制器等价实现,从而表明线性自抗扰控制具有广泛的适用性,即只要其他线性控制方法能够控制的系统,线性自抗扰控制同样可以适用.为简化线性自抗扰控制器参数整定,本文针对工业过程中广泛存在的PID控制器,提出将PID参数转化为二阶自抗扰控制参数的方法.该方法转化的线性自抗扰参数以带宽形式表示,从而保留了传统线性自抗扰简单易调的特性,为线性自抗扰控制在工业过程的应用准备了基础.     

A Novel Robust Attitude Control for Quadrotor Aircraft Subject to Actuator Faults and Wind Gusts

A novel robust fault tolerant controller is developed for the problem of attitude control of a quadrotor aircraft in the presence of actuator faults and wind gusts in this paper. Firstly, a dynamical system of the quadrotor taking into account aerodynamical effects induced by lateral wind and actuator faults is considered using the Newton-Euler approach. Then, based on active disturbance rejection control (ADRC), the fault tolerant controller is proposed to recover faulty system and reject perturbations. The developed controller takes wind gusts, actuator faults and measurement noises as total perturbations which are estimated by improved extended state observer (ESO) and compensated by nonlinear feedback control law. So, the developed robust fault tolerant controller can successfully accomplish the tracking of the desired output values. Finally, some simulation studies are given to illustrate the effectiveness of fault recovery of the proposed scheme and also its ability to attenuate external disturbances that are introduced from environmental causes such as wind gusts and measurement noises.      

Robust adaptive fault‐tolerant tracking control of multiple time‐delays systems with mismatched parameter uncertainties and actuator failures

This study deals with the problem of robust adaptive fault‐tolerant tracking for uncertain systems with multiple delayed state perturbations, mismatched parameter uncertainties, external disturbances, and actuator faults including loss of effectiveness, outage, and stuck. It is assumed that the upper bounds of the delayed state perturbations, the external disturbances and the unparameterizable time‐varying stuck faults are unknown. Then, by estimating online such unknown bounds and on the basis of the updated values of these unknown bounds from the adaptive mechanism, a class of memoryless state feedback fault‐tolerant controller with switching signal function is constructed for robust tracking of dynamical signals. Furthermore, by making use of the proposed adaptive robust tracking controller, the tracking error can be guaranteed to be asymptotically zero in spite of multiple delayed state perturbations, mismatched parameter uncertainties, external disturbances, and actuator faults. In addition, it is also proved that the solutions with tracking error of resulting adaptive closed‐loop system are uniformly bounded. Finally, a simulation example for B747‐100/200 aircraft system is provided to illustrate the efficiency of the proposed fault‐tolerant design approach. Copyright © 2014 John Wiley & Sons, Ltd.     

Distributed adaptive robust tracking and model matching control with actuator faults and interconnection failures

In this paper, direct adaptive-state feedback control schemes are developed to solve the robust tracking and model matching control problem for a class of distributed large scale systems with actuator faults, faulty and perturbed interconnection links, and external disturbances. The adaptation laws are proposed to update the controller parameters on-line when all the eventual faults, the upper bounds of perturbations and disturbances are assumed to be unknown. Then a class of distributed state feedback controllers is constructed to automatically compensate the fault, perturbation and disturbance effects based on the information from adaptive schemes. The proposed distributed adaptive tracking controller can ensure that the resulting adaptive closed-loop large-scale system is stable and the tracking error decreases asymptotically to zero in the presence of uncertain faults of actuators and interconnections, perturbations in interconnection channels, and disturbances. The proposed adaptive design technique is finally evaluated in the light of a simulation example.     

Adaptive fault-tolerant control of linear systems with actuator saturation and L2-disturbances

This paper studies the problem of designing adaptive fault-tolerant H-infinity controllers for linear timeinvariant systems with actuator saturation. The disturbance tolerance ability of the closed-loop system is measured by an optimal index. The notion of an adaptive H-infinity performance index is proposed to describe the disturbance attenuation performances of closed-loop systems. New methods for designing indirect adaptive fault-tolerant controllers via state feedback are presented for actuator fault compensations. Based on the on-line estimation of eventual faults, the adaptive fault-tolerant controller parameters are updated automatically to compensate for the fault effects on systems. The designs are developed in the framework of the linear matrix inequality （LMI） approach, which can guarantee the disturbance tolerance ability and adaptive H-infinity performances of closed-loop systems in the cases of actuator saturation and actuator failures. An example is given to illustrate the efficiency of the design method.     

Prescribed-performance fault-tolerant control for feedback linearisable systems with an aircraft application

This paper investigates fault-tolerant control (FTC) for feedback linearisable systems (FLSs) and its application to an aircraft. To ensure desired transient and steady-state behaviours of the tracking error under actuator faults, the dynamic effect caused by the actuator failures on the error dynamics of a transformed model is analysed, and three control strategies are designed. The first FTC strategy is proposed as a robust controller, which relies on the explicit information about several parameters of the actuator faults. To eliminate the need for these parameters and the input chattering phenomenon, the robust control law is later combined with the adaptive technique to generate the adaptive FTC law. Next, the adaptive control law is further improved to achieve the prescribed performance under more severe input disturbance. Finally, the proposed control laws are applied to an air-breathing hypersonic vehicle (AHV) subject to actuator failures, which confirms the effectiveness of the proposed strategies.     

Robust H ∞ and adaptive tracking control against actuator faults with a linearised aircraft application

This article studies the problem of designing adaptive fault-tolerant H _∞ tracking controllers for a class of aircraft flight systems against general actuator faults and bounded perturbations. A robust adaptive state-feedback controller is constructed by a stabilising controller gain and an adaptive control gain function. Using mode-dependent Lyapunov functions, linear matrix inequality-based conditions are developed to find the controller gain such that disturbance attenuation performance is optimised. Adaptive control schemes are proposed to estimate the unknown controller parameters on-line for unparametrisable stuck faults and perturbation compensations. Based on Lyapunov stability theory, it is shown that the resulting closed-loop systems can guarantee asymptotic tracking with H _∞ performances in the presence of faults on actuators and perturbations. An application to a decoupled linearised dynamic aircraft system and its simulation results are given.     

Fault-tolerant control of linear systems using adaptive virtual actuator

In this paper, design and development of fault-tolerant control (FTC) is investigated for linear systems subject to loss of effectiveness and time-varying additive actuator faults as well as an external disturbance using the fault-hiding approach. The main aim of this approach is to keep the nominal controller and to design a virtual actuator that is inserted between the faulty plant and the nominal controller in order to hide actuator faults and disturbances from the nominal controller, and consequently the performance of the system before and after the occurrence of actuator faults is kept to be the same. The proposed adaptive virtual actuator does not require a separated fault detection, isolation and identification (FDII) unit and both state and output feedback cases are considered. An illustrative example is given to demonstrate the effectiveness of the proposed adaptive virtual actuator in both cases.     

Robust fault-tolerant controller design for linear time-invariant systems with actuator failures: an indirect adaptive method

In this paper, indirect adaptive state feedback control schemes are developed to solve the robust faulttolerant control (FTC) design problem of actuator fault and perturbation compensations for linear time-invariant systems. A more general and practical model of actuator faults is presented. While both eventual faults on actuators and perturbations are unknown, the adaptive schemes are addressed to estimate the lower and upper bounds of actuator-stuck faults and perturbations online, as well as to estimate control effectiveness on actuators. Thus, on the basis of the information from adaptive schemes, an adaptive robust state feed-back controller is designed to compensate the effects of faults and perturbations automatically. According to Lyapunov stability theory, it is shown that the robust adaptive closed-loop systems can be ensured to be asymptotically stable under the influence of actuator faults and bounded perturbations. An example is provided to further illustrate the fault compensation effectiveness.     

Robust fault-tolerant controller design for linear time-invariant systems with actuator failures: an indirect adaptive method

In this paper, indirect adaptive state feedback control schemes are developed to solve the robust faulttolerant control (FTC) design problem of actuator fault and perturbation compensations for linear time-invariant systems. A more general and practical model of actuator faults is presented. While both eventual faults on actuators and perturbations are unknown, the adaptive schemes are addressed to estimate the lower and upper bounds of actuator-stuck faults and perturbations online, as well as to estimate control effectiveness on actuators. Thus, on the basis of the information from adaptive schemes, an adaptive robust state feed-back controller is designed to compensate the effects of faults and perturbations automatically. According to Lyapunov stability theory, it is shown that the robust adaptive closed-loop systems can be ensured to be asymptotically stable under the influence of actuator faults and bounded perturbations. An example is provided to further illustrate the fault compensation effectiveness.