基于最小特征值的挠性航天器执行器故障自适应补偿技术

本文针对挠性航天器执行器故障问题,提出了一种基于最小特征值的自适应故障补偿方法.首先,针对由故障和挠性模态引起的系统不确定性进行参数化;其次,为了解决由故障引起的控制增益矩阵的不确定性,构造了新的控制增益矩阵,并利用该矩阵的最小特征值设计标称控制信号;而后,设计自适应律对标称控制信号中的不确定参数进行估计,构成自适应控...     

具有执行器故障的四旋翼无人机自适应预定性能控制

针对具有执行器故障的四旋翼无人机,提出一种自适应预定性能控制方案.首先,基于内环姿态控制及外环位置控制的双闭环控制策略,将无人机系统解耦为位置子系统和姿态子系统;其次,设计自适应控制方案,对存在的执行器故障参数进行自适应估计,有效地解决了执行器故障下无人机稳定控制问题;然后,提出一种预定性能控制策略,保证系统的暂稳态性能满足预先给定的性能指标;最后,通过仿真实例验证所提出方法的有效性.     

飞翼飞行器的操纵面故障自适应补偿控制

本文针对具有操纵面卡死、失效故障以及执行器饱和的飞翼飞行器纵向运动,考虑系统的预定动态性能,提出了一种自适应反步补偿跟踪控制方案.设计预定动态性能(prescribed performance bound,PPB)边界以保证系统的跟踪误差,采用二阶指令滤波器限制执行器的饱和,通过控制分配避免执行器故障后对横侧向运动的影响.所设计的自适应反步补偿跟踪控制律能够保证系统对参考信号的渐近跟踪.仿真结果表明了本文方法的有效性.     

基于MMST分组的一类MIMO非线性系统执行器故障自适应补偿控制

在多输入多输出(Multiple-input multiple-output,MIMO)非线性系统的执行器故障容错控制问题中,控制器能够处理的执行器故障集合的大小与执行器分组方法有很大关系.为扩大系统可处理的执行器故障集合,本文针对一类具有执行器故障的MIMO非线性最小相位系统,提出基于多模型切换(Multiple model switching and tuning,MMST)执行器分组的自适应补偿控制方法.考虑系统的执行器卡死、部分失效和完全失效故障,在微分几何反馈线性化的基础上,研究基于多模型切换的执行器分组切换指标和切换策略,设计了基于反演控制的自适应补偿跟踪控制律,所设计的控制律能保证系统在执行器故障时闭环稳定,渐近跟踪给定的参考信号,且提出的分组方法扩大了可补偿的执行器故障集合.仿真结果表明了本文设计方法的有效性.     

双容液位系统的不确定时滞的鲁棒容错控制

针对双容液位控制系统的执行器失效等故障,通过线性化建模,研究了鲁棒自适应容错控制问题。首先在系统无故障正常工作时,考虑建模误差、输入信号的稳定性、系统参数等不确定性因素,利用不确定性上界自适应估计,设计了不确定时滞鲁棒控制器。同时,对系统进行故障检测,研究了一种修正控制律的自适应鲁棒容错控制器设计方法,该控制器通过修补执行器故障所带来的影响使该系统最终有界稳定。最后,通过仿真试验,验证了提出的方法的有效性。     

双容液位系统的不确定时滞的鲁棒容错控制

针对双容液位控制系统的执行器失效等故障,通过线性化建模,研究了鲁棒自适应容错控制问题。首先在系统无故障正常工作时,考虑建模误差、输入信号的稳定性、系统参数等不确定性因素,利用不确定性上界自适应估计,设计了不确定时滞鲁棒控制器。同时,对系统进行故障检测,研究了一种修正控制律的自适应鲁棒容错控制器设计方法,该控制器通过修补执行器故障所带来的影响使该系统最终有界稳定。最后,通过仿真实验,验证了提出方法的有效性。     

基于LMI可靠跟踪控制器设计

针对具有不确定性的线性定常系统,提出了考虑执行器故障的可靠跟踪控制器设计问 题.在更一般、更实际的执行器故障模型的基础上,给出了系统输出信号渐近跟踪参考输入信 号可靠跟踪控制存在的充分条件.通过求解线性矩阵不等式(LMI)完成状态反馈可靠跟踪控制 器设计.利用仿真数例验证了文中提出的设计方法的可行性,并且通过对可靠跟踪控制系统与 不考虑故障的标准跟踪控制系统的比较,进一步说明对系统进行可靠跟踪控制的必要性.     

预设跟踪性能下车辆队列执行器故障主动容错控制

研究预设跟踪性能下的车辆队列执行器故障主动容错控制问题.考虑执行器部分失效和偏移故障情形,设计Luenberger观测器和自适应残差阈值以实现执行器故障检测.在此基础上,为了确保执行器故障下的车辆队列暂态和稳态性能,在预设跟踪性能框架下,设计基于反步法的主动容错控制算法,在满足预设性能的前提下,实现车辆队列跟踪误差有界,且车辆间距满足安全性和紧凑性约束.仿真结果验证了所提出主动容错控制算法的有效性.     

线性系统考虑执行器故障的鲁棒控制

针对线性定常系统，提出了考虑执行器故障的鲁棒控制器设计问题。利用更一般、更实际的执行器故障模型，给出了系统输出渐近跟踪参考输入信号的鲁棒控制存在的充分条件。通过求解线性矩阵不等式（LMI）完成状态反馈控制器的设计。数例仿真验证了本文提出设计方法的可行性，并且通过所设计的鲁棒控制系统与不考虑故障控制系统的比较，进一步说明对系统进行鲁棒设计的必要性。     

线性系统区域稳定的可靠控制

针对线性系统,提出了抵御系统执行器故障和不确定性的状态反馈区域稳定可靠控制设计问题.通过对具有连续增益故障控制系统的分析,给出了区域稳定可靠控制器存在的充分条件和设计方法.所设计的区域稳定可靠控制器可以消除执行器故障对闭环系统极点配置的影响.使用线性矩阵不等式(LMI)表示的结果能够容易得到可靠控制增益的数值解.通过CH-47双旋翼直升机的实例仿真验证了该结果的可行性.通过比较区域稳定正常控制系统和可靠控制系统,进一步说明对系统进行可靠控制设计的必要性.     

航天器自适应快速非奇异终端滑模容错控制

针对存在外部干扰、转动惯量矩阵不确定以及执行器故障的航天器姿态跟踪控制问题,本文提出了基于自适应快速非奇异终端滑模的有限时间收敛故障容错控制方案.通过引入能够避免奇异点,且具有有限时间收敛特性的快速非奇异终端滑模面,设计了满足多约束条件有限时间收敛的姿态跟踪容错控制律,利用参数自适应方法使控制器不依赖转动惯量和外部干扰的上界信息.Lyapunov稳定性分析表明:在存在外部干扰、转动惯量矩阵不确定以及执行器故障等约束条件下,本文设计的控制律能够保证闭环系统的快速收敛性,而且对执行器故障具有良好的容错性能.数值仿真校验了该控制律在姿态跟踪控制中的优良性能.     

基于学习观测器的航天器指定时间跟踪控制

针对一类含有外部扰动和执行器故障的刚体航天器姿态控制系统,提出一种基于自适应学习观测器的指定时间容错控制器的设计方案.首先,系统性地给出一种改进型自适应学习观测器设计方案,基于自适应学习观测器框架,设计航天器姿态系统的学习观测器实现对系统的综合扰动值估计;然后,利用综合扰动的估计信息和滑模控制理论设计指定时间容错跟踪控制器,使得系统的姿态角能够在指定时间跟踪指令信号,系统的收敛时间可通过容错控制器的参数预先设置,且与系统的初始状态值无关;接着,基于Lyapunov稳定性理论验证含有故障的姿态控制系统能够在指定时间内稳定;最后,通过数值仿真,与已有的观测器和有限时间控制方案进行对比,表明所提出方案的有效性和可行性.     

Retrofit fault‐tolerant tracking control design of an unmanned quadrotor helicopter considering actuator dynamics

This paper presents a retrofit fault‐tolerant tracking control (FTTC) design method with application to an unmanned quadrotor helicopter (UQH). The proposed retrofit fault‐tolerant tracking controller is developed to accommodate loss‐of‐effectiveness faults in the actuators of UQH. First, a state feedback tracking controller acting as the normal controller is designed to guarantee the stability and satisfactory performance of UQH in the absence of actuator faults, while actuator dynamics of UQH are also considered in the controller design. Then, a retrofit control mechanism with integration of an adaptive fault estimator and an adaptive fault compensator is devised against the adverse effects of actuator faults. Next, the proposed retrofit FTTC strategy, which is synthesized by the normal controller and an additional reconfigurable fault compensating mechanism, takes over the control of the faulty UQH to asymptotically stabilize the closed‐loop system with an acceptable performance degradation in the presence of actuator faults. Finally, both numerical simulations and practical experiments are conducted in order to demonstrate the effectiveness of the proposed FTTC methodology on the asymptotic convergence of tracking error for several combinations of loss‐of‐effectiveness faults in actuators.     

Adaptive decentralized fault‐tolerant tracking control for large‐scale nonlinear systems with input quantization

In this paper, an adaptive decentralized tracking control scheme is designed for large‐scale nonlinear systems with input quantization, actuator faults, and external disturbance. The nonlinearities, time‐varying actuator faults, and disturbance are assumed to exist unknown upper and lower bounds. Then, an adaptive decentralized fault‐tolerant tracking control method is designed without using backstepping technique and neural networks. In the proposed control scheme, adaptive mechanisms are used to compensate the effects of unknown nonlinearities, input quantization, actuator faults, and disturbance. The designed adaptive control strategy can guarantee that all the signals of each subsystem are bounded and the tracking errors of all subsystems converge asymptotically to zero. Finally, simulation results are provided to illustrate the effectiveness of the designed approach.     

未知时变惯量航天器自适应姿态跟踪容错控制

针对存在未知时变惯量不确定性、执行机构衰退故障和外部干扰力矩的非刚体航天器系统,研究了航天器自适应姿态跟踪容错控制问题,结合非线性鲁棒控制方法、自适应方法、容错控制理论和参数估计方法,提出了一种鲁棒自适应姿态跟踪容错控制器。所设计的控制器克服了执行器故障、惯量不确定性以及外界干扰对系统稳定性的影响,保证了航天器姿态及角速度能够跟踪上时变的期望状态,实现了跟踪误差系统最终一致有界稳定。最后通过数字仿真验证了所提方法的有效性,并且与已有方法进行了对比,说明了所提方法的优越性。     

Fixed‐time attitude tracking control for spacecraft based on adding power integrator technique

In this article, the fixed‐time attitude tracking problem for rigid spacecraft is investigated based on the adding‐a‐power‐integrator control technique. First, a fixed‐time attitude tracking controller is designed to guarantee fixed‐time convergence of tracking errors. Then, by considering the presence of random disturbance and actuator faults, an adaptive fault‐tolerant attitude tracking controller is designed to guarantee tracking errors converge to a residual set of zero in a fixed time. The complete bounds on settling time are derived independently of initial conditions. The simulation results illustrate the highly precise and robust attitude control performance obtained by using the proposed controllers.     

An adaptive integral sliding mode FTC scheme for dissimilar redundant actuation system of civil aircraft

ABSTRACT

This paper proposed a new adaptive integral sliding mode FTC scheme to deal with the actuator faults and failure. The scheme combines integral sliding mode control, control allocation scheme and adaptive strategy. The unknown actuator faults are handled by adaptive modulation gain of nonlinear ISMC law. To cope with complete failure, control allocation scheme is integrated with the baseline controller to provide tolerance. The proposed strategy relies on the estimate of actuator effectiveness. Therefore, an adaptive sliding mode observer based fault reconstruction scheme is proposed in this paper. The proposed scheme is implemented on dissimilar redundant actuation system driven by hydraulic and electro-hydraulic actuators. In nominal and faulty conditions, both actuators are contributing to achieving the desired control surface deflection. However, when the actuator failure occurs, the control signals are reallocated to the redundant actuator. The problem of dynamics mismatch is addressed using fractional order controller designed in an inner loop. The comparison with the existing literature is also conducted in the simulation to validate the dominant performance.     

Redundant Input Safety Tracking for Omnidirectional Rehabilitative Training Walker with Control Constraints

This study proposes a nonlinear safety tracking method based on redundant degrees of freedom with control constraints to protect against actuator faults that may occur in robotic rehabilitative walkers. A redundant input model with uniform actuator faults is constructed by separating the corresponding columns of the control matrix, and an adaptive robust control method is presented to deal with the separated term that is considered in relation to the extrinsic bounded interference that occurs on robotic walker systems. Based on the backstepping technique, an adjustable control law can be designed to maintain stability in terms of solving linear matrix inequality. The trajectory tracking error performance and the velocity tracking error performance are derived simultaneously. As an application, simulation results confirm the effectiveness of the proposed method and verify that the walker can provide safe sequential motions even when one wheel actuator fails.     

非线性动态突变系统的多模型自适应执行器故障补偿设计

本文针对因多重不确定执行器故障而引起系统动态突变的非线性系统,设计了一种基于多模型切换的自适应执行器故障补偿控制策略,以提高系统应对动态突变的能力,同时实现不确定执行器故障的快速精确补偿.针对执行器故障模式的不确定性问题,采用基于多模型的参数估计方法,设计了自适应控制器组;基于最优性能指标函数,提出了一种控制切换机制,...     

临近空间飞行器的模型参考滑模容错控制

针对临近空间飞行器中未知的执行器控制效益损失和漂移故障,提出了一种模型参考滑模容错控制方法,保证故障系统对参考模型的稳定跟踪性能。利用跟踪误差系统设计容错控制器,首先构造积分滑模面,以增强系统鲁棒性并消除稳态误差;随后,在无需故障诊断单元的条件下设计模型参考滑模控制律,使其增益能实现自适应调节以处理未知故障影响,其中自适应律基于李雅普诺夫稳定性理论设计,保证闭环系统稳定。在临近空间飞行器纵向动力学模型上的仿真验证表明,该方法能处理执行器中发动机节流阀调节通道和升降舵偏转量通道的不同故障,保证系统获得满意的鲁棒容错跟踪性能。