面向稳定目标的深空探测器可重构性评价与自主重构设计

针对现有研究中缺乏指标指导深空探测器控制系统重构策略设计的量化指标的问题,本文研究了在资源受限且不可维修的条件下,面向稳定目标的深空探测器可重构性评价和自主重构设计问题。本文将在地面设计阶段考虑深空探测器控制系统的可重构性,并基于可重构性评价指标指导系统的自主重构控制方法,从设计角度提高深空探测器控制系统运行质量。首先通过左右互质分解的技术手段,基于稳定性目标,定量地给出了系统可重构性指标,描述并评价了深空探测器控制系统的重构能力;然后基于所得指标,为控制系统重构设计提供理论参考依据;最后通过数值仿真证明了该方法的有效性和正确性。     

一种线性系统可重构控制分析方法

提出了一种线性系统在线或者离线的可重构控制分析方法,该方法基于功能目标模型,能够定性分析线性系统的可重构控制问题, 包括发生多个故障时是否具有可重构能力,采用哪些组件和何种控制方法,以及重构后系统是否能达到期望的控制目标等.首先定义了功能、目标、最小重构单元状态、可行集等概念,并基于这些概念建立系统功能目标模型.该模型由功能目标关系和各个目标的可行集组成. 总目标的可行集为系统顶层可行集,可重构控制方案的选择基于顶层可行集.应用本文方法,离线建立起控制系统的功能目标模型后, 可以在线或离线分析其多种故障模式下的可重构问题,还可以用于指导可重构性设计.最后,给出一个卫星控制系统可重构控制分析的例子.     

航天器控制系统可重构性的内涵与研究综述

可重构性设计是提高航天器在轨运行质量的有效途径,可以从系统层面克服航天器控制系统固有可靠性不足、星上资源受限以及在轨故障不可维修等缺陷,目前已引起控制理论和航天器控制工程等领域的高度重视与广泛关注.本文首先结合航天器控制系统的固有特点,具体介绍可重构性的研究意义与概念内涵.然后从评价与设计两方面,详细梳理航天器控制系统可重构性的研究内容与研究现状.最后对目前可重构性研究领域中存在的一些问题以及未来可能的发展方向进行深入探讨.     

分段重构控制策略

现有控制重构方案均需要精确的故障定位,存在着诊断过程中系统耐故障能力不足 的缺陷.文中提出一种分段重构的重构策略以解决该问题.只要故障被定位至某些适当的元 件集合,控制重构就开始进行,并随诊断过程的深入分段推进.该策略被转化为一个鲁棒模型 跟踪问题,并提出一种基于H2/H∞混合性能指标优化的控制律设计方法实现.针对某飞行器 具体设计了可重构飞控系统,结果表明该方法具有很好的重构效果.     

可重构机械臂反演时延分散容错控制

针对存在模型参数不确定性的可重构机械臂系统执行器故障,提出一种基于反演设计与时延技术相结合的容错控制方法.该方法利用反演设计的基本思想,通过神经网络补偿子系统动力学模型中的参数不确定项和关联项.利用时延控制的逼近能力来补偿执行器的故障,使得故障发生时能及时实现容错控制.该方法具有不需要在线进行故障诊断的特点,仿真结果表明了所提出控制方法的有效性.     

面向重构目标的控制系统可重构性

定义了控制系统的稳定目标、弱目标、强目标、直接目标和故障隐蔽目标等5个重构目标. 以故障隐蔽目标为基础,依次给出了稳定、弱重构、强重构和直接重构目标的可重构性条件. 稳定目标的重构条件从能控能观结构特性方面考虑,其它几个目标主要以秩条件的形式给出. 应用于线性多变量系统的数例,进行了控制可重构性的分析,为控制律重构的综合设计提供重要依据.     

风力发电系统传感器故障诊断

针对非线性风力发电系统,提出了一种基于滑模观测器的传感器故障诊断方法.基于考虑传感器加性故障的非线性动态模型,利用T--S模糊理论建立风力发电系统全局T--S模型,设计模糊T--S系统滑模故障观测器,产生对故障具有敏感性的残差,实现故障检测.通过等价输出控制方法来维持滑模运动,直接获取故障信息,重构传感器故障.最后以三叶片水平轴风力发电系统为例,仿真验证了该方法的有效性与可靠性.     

基于多模型自适应的飞行控制系统重构与优化

对飞行器执行机构受损或失效情况下其飞行控制规律重构的问题,提出一种基于线性二次最优控制理论的多模型自适应控制重构技术方案。利用线性二次调节器获得参考模型,基于故障诊断与检测技术,运用Lyapunov稳定性理论,确保闭环控制系统的严格正实性和全局渐进稳定性。根据飞行器的动力学控制规律,进行故障辨识和模型切换,实现故障状态下飞行控制规律的重构与优化设计。针对典型故障情况进行飞行器控制重构仿真验证,结果表明系统能够在舵面部分失效下完成控制重构,保证有效飞行器运行控制。     

航天器控制系统的自主诊断重构技术

自主诊断重构是确保航天器控制系统安全可靠自主运行的关键技术之一.本文针对航天器资源严重受限的客观情况,改变传统一味追求华丽算法与豪华配置的设计理念,从航天器的自身特性出发,深入挖掘诊断重构问题的本质,提出基于可诊断性与可重构性评价设计的研究思路.文章首先介绍了航天器自主诊断重构技术的发展现状,分析了当前技术的不足之处并探究了其深层原因;然后,提出了通过可诊断性与可重构性评价设计从根本上提高系统自主诊断重构能力的全新思路,梳理了其研究内容与研究概况;最后,对航天器控制系统自主诊断重构技术的发展趋势进行了展望.     

控制面故障下的飞机运动建模与重构控制能力分析及设计

对控制面故障影响飞机运动的机理进行了推导,系统地阐述了控制面故障下的飞机运动建模方法。在建模的基础上,对故障系统的可重构性进行研究。分别从线性系统运动和物理运动两个方面,给出了可重构能力的评定方案。推导了误差反向传播的前向神经网络用于控制系统设计时满足Lyapunov稳定性的学习算法,提出了一种新型的采用反向传播神经网络补偿常规控制器的重构飞行控制设计方案。采用非线性飞机运动模型对控制器进行了仿真,验证了重构飞行控制器的性能。     

Reconfigurable Control Structure for Robots in Assembly

The increased use of changeable characteristics in modern manufacturing and robotic systems and applications call for improved system control design that offers some degree of reconfigurability. The need for control reconfiguration of robotic systems arises due to some inherent characteristics of the robotic system, variations of robot parameters due to environmental changes, major task changes typical in production changeover or manufacturing system reconfiguration, or geometry changes due to the reconfiguration of modular manipulators. In this paper, a reconfigurable controller, the Supervisory Control Switching System (SCSS), is proposed to meet the new on-line demands for changeability in robotic systems. The SCSS is capable of selecting the most suitable controller for a particular task or situation, from separate controllers designed a priori. The applicability and effectiveness of the developed switching control scheme have been illustrated through computer simulations of an AdeptOne SCARA manipulators carrying out assembly tasks.     

考虑传感器故障的导弹姿态控制系统主动容错控制研究

针对导弹姿态控制系统惯性传感器故障,提出了基于信号重构的主动容错控制方法.分别利用基于梯形算法的数值积分器和有限时间收敛微分器对姿态角信号和角速率信号进行重构,当在线诊断出姿态角或角速率传感器故障时,以重构信号代替故障信号进行反馈控制来实现系统的主动容错控制.在建立导弹姿态控制系统模型并采用次最优控制方法设计输出反馈控制器的基础上,对所设计的主动容错控制方法进行仿真,仿真结果表明该方法是有效的.     

基于网络控制系统的水下自主航行器制导系统结构

在现代控制系统中,网络控制系统可以用最小成本实现柔性系统,该柔性系统可以完成包括功能可重新配置的许多任务;网络控制系统采用公用的总线结构,使得系统具有更加有效的灵活功能、更好的资源共享、降低系统的维护成本,网络控制系统的最大问题是由于网络而产生的时延和数据包的丢失;研究了基于网络控制原理的水下自主航行器制导系统,详细分析了水下自主航行器网络控制系统的稳定性问题和基于时间触发的TTCAN高层协议;论文旨在通过对水下自主航行器网络控制系统结构的研究,指出其结构的意义和进一步的研究领域.     

Fault‐Tolerant Control Allocation for Overactuated Nonlinear Systems

This paper addresses the problem of fault‐tolerant control allocation for input affine nonlinear systems. The proposed scheme is divided in three main tasks: fault detection and estimation using a nonlinear observer, fault isolation through a bank of unknown input observers with a resetting policy to reduce the effects of nonlinearities and control reconfiguration based on reduced order allocation. Analytical results regarding the isolability and reconfigurability of actuator faults are derived and a simulation example is used to illustrate the the proposed fault tolerant control methodology.     

Design of a fault tolerant control system incorporating reliability analysis and dynamic behaviour constraints

In highly automated aerospace and industrial systems where maintenance and repair cannot be carried out immediately, it is crucial to design control systems capable of ensuring desired performance when taking into account the occurrence of faults/failures on a plant/process; such a control technique is referred to as fault tolerant control (FTC). The control system processing such fault tolerance capability is referred to as a fault tolerant control system (FTCS). The objective of FTC is to maintain system stability and current performance of the system close to the desired performance in the presence of system component and/or instrument faults; in certain circumstances a reduced performance may be acceptable. Various control design methods have been developed in the literature with the target to modify or accommodate baseline controllers which were originally designed for systems operating under fault-free conditions. The main objective of this article is to develop a novel FTCS design method, which incorporates both reliability and dynamic performance of the faulty system in the design of a FTCS. Once a fault has been detected and isolated, the reconfiguration strategy proposed in this article will find possible structures of the faulty system that best preserve pre-specified performances based on on-line calculated system reliability and associated costs. The new reconfigured controller gains will also be synthesised and finally the optimal structure that has the ‘best’ control performance with the highest reliability will be chosen for control reconfiguration. The effectiveness of this work is illustrated by a heating system benchmark used in a European project entitled intelligent Fault Tolerant Control in Integrated Systems (IFATIS EU-IST-2001-32122).     

Robust control scheme based on an uncertainty and disturbance estimator for a quadrotor with motor failures

This paper proposes a new robust fault tolerant control architecture based on a disturbance observer. The control architecture is composed of a nominal controller and a rotor's fault observer capable to identify and estimate motors' degradation performance. Besides, is designed for a quadrotor vehicle and validated in critical and noncritical motors' failures. For both failure cases, each motor performance is analyzed to counteracted the failure and restore the system stability. If the practical stability is not recovered (critical case) a control reconfiguration is performed for safe landing. Experimental tests are carried out in real time to illustrate the effectiveness of the proposed architecture when confronting the stability of the system with aggressive disturbances or uncertainties.     

Fault detection model‐based controller for process systems

This paper develops a model‐based control system for fault detection and controller reconfiguration using stochastic model predictive control (MPC). The system can determine online the optimal control actions, detect faults quickly, and reconfigure the controller accordingly. Such a system can perform its function correctly in the presence of internal faults. A fault detection model based (FDMB) controller consists of two main parts: the first is fault detection and diagnosis (FDD) and the second is controller reconfiguration (CR). Systems subject to such abrupt failures are modeled as stochastic hybrid systems with variable‐structure. This paper deals with three challenging issues: design of the fault‐model set; estimation of hybrid multiple models; and stochastic MPC of hybrid multiple models. For the first issue, we propose a simple scheme for designing a fault model set based on random variables. For the second issue, we consider and select a fast and reliable FDD system applied to the above model set. Finally, we develop a stochastic MPC scheme for multiple model CR with soft switching signals based on the weighted probabilities of the outputs of different models. Simulations for the proposed FDMB controller are illustrated and analyzed. Copyright © 2011 John Wiley and Sons Asia Pte Ltd and Chinese Automatic Control Society     

Decentralized observer-based controller design for large-scale systems with quantized measurements and actuator faults

This paper is focused on designing observer-based decentralized memory feedback controller for ensuring the asymptotic mean square stability of the large-scale systems with minimum H_∞ performance index. Precisely, the unknown interconnection between each subsystems of a large-scale system is assumed to satisfy quadratic bounds, and measured output is quantized by a logarithmic quantizer. Also, the signals are transmitted through the actuator component wherein the occurrence of fault is indispensable. Thus, the impact of faults in actuator is considered in control design to tolerate the fault effects and also for ensuring robust performance. A state space representation of the system is formulated to reconstruct the unmeasurable states via the available informations of input/output dynamics. Based on the designed observer, a decentralized memory feedback controller is developed. Specifically, in terms of linear matrix inequalities, the stability conditions are derived and which are sufficient to guarantee the desired result. At last, simulations are carried out for two numerical examples to validate the potential of the theoretical result.