汽车主动悬架系统H∞控制器的降阶

基于整车模型设计的主动悬架控制系统,控制器阶数往往较高.在保证主动悬架闭环系统性能的情况下如何尽可能地降低控制器的阶数,是有待解决的问题.本文首先建立汽车7自由度整车悬架模型.针对人体敏感的振动频率范围,设计汽车主动悬架H_∞控制器.在此基础上采用Hankel范数最优降阶法对所设计的高阶控制器进行降阶研究,与模态截取法、均衡截取法进行比较,结果显示Hankel范数最优降阶法能获得更好的降阶效果.对采用降阶和全阶控制器的主动悬架系统进行仿真的结果表明,Hankel范数最优降阶法在较大程度地降低控制器阶数的同时,闭环系统频域和时域特性没有明显降低且汽车乘坐舒适性良好.     

执行器有时滞的馈能式主动悬架的鲁棒控制

车辆用的馈能式主动悬架系统具有不确定参数,而且执行器有时滞.为了保证其稳定性、减振性和能量回收性能,我们提出了一种保成本/H∞鲁棒控制器设计方法.对车辆悬架系统性能方面的要求,用二次型加权性能指标和H∞性能指标反映.定义了一个Lyapunov函数代表这两个性能指标;根据这个Lyapunov函数,把闭环系统设计问题转化为一组线性矩阵不等式以求解控制器.根据直流电机工作原理,分析了参数摄动和执行器时滞对系统能量平衡的影响,推导出了能量平衡方程.最后对二自由度1/4车悬架模型进行了仿真;结果表明:对一定范围内的参数摄动和有界时滞,悬架系统在有效减振的同时,实现了能量的回收.     

马尔可夫跳变系统基于观测器的有限时间容错控制

针对具有一般不确定转移速率的单边Lipschitz Markovian跳变系统,设计了有限时间故障估计观测器和容错控制器.首先,提出一种自适应的有限时间故障估计观测器,它对未知输入具有鲁棒性,能够同时估计出系统的状态、执行器故障和传感器故障,并确保了误差系统的H_∞有限时间有界.然后,基于所估计的状态和执行器故障,提出一种有限时间故障容错控制方法确保闭环系统H_∞有限时间有界.通过线性矩阵不等式的形式,给出了所设计的有限时间观测器和控制器存在的充分条件.最后,通过一个仿真实例,验证了所提方法的有效性.     

不确定系统鲁棒容错控制

针对不确定线性系统,关于连续型增益故障模式,利用有界实引理和线性矩阵不等式LMI,推导了系统H_∞指标约束下鲁棒镇定及容错控制的充分必要条件,并给出了状态反馈H_∞鲁棒容错控制器的设计方法,从而系统在执行器失效情况下用H_∞指标约束鲁棒容错达到控制的目的.最后,将所提出的鲁棒容错控制方法应用于某一不确定线性系统,仿真结果表明设计的鲁棒控制器不仅能保证系统在执行器失效时闭环系统仍渐近稳定,并且能达到给定的H_∞性能指标,从而验证了所提出方法的可行性和有效性.     

一类机械臂系统自适应有限时间有界H∞跟踪控制

考虑一种电机驱动的单连杆机械臂系统在受到输出约束时的自适应有限时间H∞跟踪控制问题.一个有限时间有界H∞性能的新概念被提出,并结合障碍Lyapunov函数(BLF)、神经网络自适应技术、有限时间控制理论和H_∞控制理论,提出了一种该系统在输出受限条件下的自适应神经有限时间有界H_∞跟踪控制器设计方法,避免了许多有限时间控制文献中控制器设计时出现的奇点问题,实现了该机械臂系统的有限时间有界H_∞轨迹跟踪控制.所设计的控制器保证了系统跟踪误差能够被约束在预先给定的范围内,并且所有状态能在有限时间内收敛到平衡状态的邻域内,同时对外部扰动具有H_∞性能.仿真结果验证了所设计控制器的有效性和优越性.     

时延转移概率部分未知的网络控制系统鲁棒H_∞故障检测

针对具有时延的离散网络控制系统,研究了时延转移概率部分未知条件下的鲁棒H∞故障检测问题.首先,利用两个独立的有限维数的Markov链分别描述传感器至控制器时延及控制器至执行器时延,把网络控制系统建模为具有两个Markov链的控制系统.在此基础上构造了故障检测滤波器,利用状态增广的方法建立了闭环系统模型.然后,以矩阵不等式的形式得到了闭环系统随机稳定并满足给定H_∞性能的条件,给出了相应控制器、滤波器增益矩阵及最小H_∞衰减水平的求解方法,并得到了转移概率和最小H_∞衰减水平之间的关系.最后实例仿真表明,所得到的故障检测滤波器不仅对故障敏感而且对外部扰动具有鲁棒性.     

基于连续故障模型的Delta算子系统可靠鲁棒H_∞控制

研究具有执行器故障的Delta算子线性不确定系统的可靠鲁棒H_∞问题.设计控制器,确保在执行器发生故障时闭环系统仍能保持鲁棒稳定,且满足给定的H_∞指标.针对执行器连续故障模型,运用线性矩阵不等式方法,得到Delta算子系统α-次优可靠鲁棒H_∞状态反馈控制器的存在条件和设计方法,并进一步给出了Delta算子系统最优可靠鲁棒H_∞控制器的设计方法.数值算例表明,该设计方法是有效而可行的.

Abstract：

The reliable robust H_∞ control problem is studied for the Delta operator systems with actuator failure.The purpose is to design a controller which can tolerate actuator failures,such that the Delta operator closed-loop system is asymptotic stable for all admissible uncertainties,and the H_∞-performance index of the closed-loop system is less than a given upper bound.A more practical model of actuator failure,continuous failure model,is considered.A sufficient condition for the existence of the state feedback α-suboptimal reliable robust H_∞ controllers is derived by using the linear matrix inequality approach.Then the design procedures of such controllers and optimal reliable robust H_∞ controllers are proposed respectively.A numerical example demonstrates the effectiveness and feasibility of the design methods.     

广义系统H∞可靠性控制

通过对更一般形式的执行器和传感器故障模型分析,研究了广义系统基于观测器的H∞可靠性控制器设计问题.利用带有约束的广义代数Riccati不等式(GARI),给出执行器故障情况下,广义系统H∞可靠性控制器存在的充要条件和设计方法,以及传感器故障情况下,广义系统H∞可靠性控制器存在的充分条件和设计方法.所设计的H∞可靠性控制器使得闭环广义系统容许且传递函数的H∞范数有界.同时,还将带广义约束的GARI转化成了线性矩阵不等式(LMI),进而简化了广义系统H∞可靠性控制器设计方法.     

多约束主动悬架H2/H∞混合控制器设计

利用闭环极点配置中的D-稳定性原理,给出了有硬约束的H2/H∞混合控制器的LMI条件并应用于汽车主动悬架分析.用这种方法设计的控制器,通过H∞控制性能指标保证了系统输出信号与输入信号的总能量之比小于适当的γ值,并且利用H2控制,保证了输出信号的能量与输入信号的能量在时域上的峰值比低于一个适当的μ值,同时,将闭环系统的极点配置在复平面上的一个适当区域,可以保证系统具有一定的动态性能和稳定性,比较好的解决了系统性能和系统鲁棒性之间的折衷优化控制问题.     

不确定非线性切换系统鲁棒容错H∞控制与仿真

为了克服外部扰动与执行器失效对切换系统的不良影响,使系统具有可靠性和抗干扰性,针对一类不确定非线性切换系统,研究了鲁棒容错H∞控制器设计与切换问题.假设系统中存在外部扰动,并且所有的矩阵同时带有未知、时变和范数有界的不确定性.当有执行器失效,并使得每个子系统均不能镇定的情况下,利用线性矩阵不等式技术和多李亚普诺夫函数法设计γ次优鲁棒H∞反馈容错控制器和切换策略,保证切换系统能全局二次稳定并且满足日∞性能指标,对得到的γ次优鲁棒H∞容错控制器进行优化,通过变量替换法获得了γ最优鲁棒H∞容错控制器.仿真结果表明,在执行器正常工作和一些执行器发生失效时,容错控制器和切换策略是有效的.     

Fault diagnosis for a class of active suspension systems with dynamic actuators’ faults

In this paper, a new fault diagnosis and fault-tolerant control method for a class of active suspension systems with actuator faults is proposed. The considered actuators have uncertain dynamic characteristics, which are the electromagnetic actuators made up with a motor control system and a ball screw transmission mechanism. To detect such suspension system actuator faults, dynamic fault diagnosis observers are designed for the actuators to estimate the possible faults. The actuators are analyzed to first and second order dynamic models, respectively, whose output can be measured but the rate is non-measurable. Then, the fault diagnosis method is developed for these two kinds of models to obtain the fault information. Using the fault estimation and adaptive control technique, a robust fault-tolerant controller is constructed to guarantee the performance of the rail vehicles in the faulty case. Finally, using the parameters of a practical suspension system, a simulation study is conducted to show the effectiveness of the proposed method.     

Adaptive backstepping‐based control design for uncertain nonlinear active suspension system with input delay

This paper addresses the control problem of adaptive backstepping control for a class of nonlinear active suspension systems considering the model uncertainties and actuator input delays and presents a novel adaptive backstepping‐based controller design method. Based on the established nonlinear active suspension model, a projector operator–based adaptive control law is first developed to estimate the uncertain sprung‐mass online, and then the desirable controller design and stability analysis are conducted by combining backstepping technique and Lyapunov stability theory, which can not only deal with the actuator input delay but also achieve better dynamics performances and safety constraints requirements of the closed‐loop control system. Furthermore, the relationship between the input delay and the state variables of this vehicle suspension system is derived to present a simple and effective method of calculating the critical input delay. Finally, a numerical simulation investigation is provided to illustrate the effectiveness of the proposed controller.     

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.     

基于LMI的鲁棒容错控制及其在卫星姿态控制中的应用

研究了一种线性不确定系统的鲁棒容错控制问题.针对执行机构和敏感器故障,运用线性矩阵不等式(LMI)方法,提出一种对执行机构和传感器失效具有完整性,且满足给定控制指标的输出反馈H∞鲁棒容错控制设计方法.将该方法应用于卫星姿态控制系统的容错控制并进行了数学仿真,仿真结果验证了方法的有效性.     

级联触发策略下非结构化道路的自主卡车队列控制

本文针对非结构化道路上自主卡车队列系统的控制问题进行研究, 设计一种基于级联触发的控制器,有效提高复杂工况下的卡车队列系统性能. 首先, 建立不依赖于道路结构的纵–横耦合卡车队列系统模型, 该模型涉及复杂环境下车辆存在故障(包括执行器、传感器的失效故障以及随机网络故障)影响. 其次, 为降低燃油消耗, 设计了基于自触发和事件触发的级联触发控制器, 并利用李雅普诺夫方法证明了系统的闭环稳定性. 此外, 通过对系统Zeno行为的分析量化, 得到了触发时间间隔的下界值, 保证了算法的实际应用性. 本文为了实现卡车系统队列稳定性控制目标, 进一步给出了控制器设计限制条件. 最后, 仿真结果表明, 所提出的控制方法不但能保证单车渐近稳定以及队列稳定, 还能有效减少执行器更新频率, 提高燃油经济性.     

Multi-objective H ∞ control for vehicle active suspension systems with random actuator delay

This article is concerned with the problem of multi-objective H _∞ control for vehicle active suspension systems with random actuator delay, which can be represented by signal probability distribution. First, the dynamical equations of a quarter-car suspension model are established for the control design purpose. Secondly, when taking into account vehicle performance requirements, namely, ride comfort, suspension deflection and the probability distributed actuator delay, we present the corresponding dynamic system, which will be transformed to the stochastic system for the problem of multi-objective H _∞ controller design. Third, based on the stochastic stability theory, the state feedback controller is proposed to render that the closed-loop system is exponentially stable in mean-square while simultaneously satisfying H _∞ performance and the output constraint requirement. The presented condition is expressed in the form of convex optimisation problems so that it can be efficiently solved via standard numerical software. Finally, a practical design example is given to demonstrate the effectiveness of the proposed method.     

不确定Delta算子系统的鲁棒H∞重构控制

讨论一类含有参数不确定和执行器故障的Delta算子系统鲁棒H_∞ 重构控制设计问题. 通过利用故障检测与隔离(FDI)技术, 在考虑不可检测故障执行器输入为能量有界的干扰信号情形下, 基于H_∞ 干扰抑制的思想, 给出了系统可鲁棒H_∞ 镇定的充分条件. 所设计的控制器可使闭环系统鲁棒稳定, 而且对可允许的不确定性和执行器故障具有一定的H_∞ 性能. 数值例子说明了本文设计方法的有效性.     

Fault detection for output feedback control systems with actuator stuck faults: A steady‐state‐based approach

The paper studies the fault detection problem for output feedback control systems with bounded disturbances and nonzero constant reference inputs. A steady‐state‐based approach is proposed which can be used to detect small actuator stuck faults including actuator outage (the stuck value is zero). These small stuck faults, especially the outage faults, cannot be detected effectively using the existing techniques. A dynamic output feedback controller and a weighting matrix are designed simultaneously. The dynamic output feedback controller stabilizes the closed‐loop system for both fault‐free and faulty cases and attenuates the effects of disturbances. By manipulating the steady‐state values of system states with the detection weighting matrix, a residual is then generated, through which actuator stuck faults including actuator outages can be detected effectively. Simulation results are included to demonstrate our design procedure. Copyright © 2009 John Wiley & Sons, Ltd.