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.     

航天器执行机构部分失效故障的鲁棒容错控制

针对航天器在轨运行时受到外部干扰以及存在执行机构部分失效故障的问题,提出一种基于白适应滑模控制的鲁棒容错控制方法．该方法利用自适应算法估计执行机构故障的最小值,并通过设计滑模变结构控制器来实现对故障的容错控制以及对干扰的抑制控制,无需精确获得执行机构故障值,从而使得设计的控制器对于故障具有一定的鲁棒性．仿真结果表明了该...     

基于迭代学习观测器的航天器姿态主动容错控制

针对含有外部扰动和执行器故障的一类航天器姿态控制系统,本文提出基于迭代学习观测器的主动容错控制方案.首先,建立了含有外部扰动和执行器故障的航天器姿态控制系统的运动学和动力学模型.其次,为了提高观测器的故障估计精度,在传统迭代学习观测器设计基础上引入上一时刻状态估计误差信息,文章提出一种改进型学习估计算法.进一步,基于滑模控制和指定时间稳定理论,利用学习观测器的故障估计信息设计指定时间主动容错控制器.与现有的航天器主动容错控制方案相比,本文所提出的算法的优势在于可以使故障系统的姿态能在指定时间跟踪上指令信号.基于Lyapunov方法,本文从理论上证明了改进型学习观测器和姿态容错控制系统的稳定性.最后,通过数值仿真,说明了所提容错控制方案的有效性和可行性.     

基于干扰观测器的航天器非奇异终端二阶滑模控制

为了消除干扰力矩和结构不确定性对卫星姿态控制性能的影响,本文提出了一种基于新型干扰观测器的非奇异终端二阶滑模控制方法.首先,文章设计了一种基于跟踪微分器的干扰观测器,来对卫星系统中的不确定项进行估计,利用估计值进行补偿,并保证估计误差在有限时间内收敛.在此基础上,文章设计一个非奇异终端滑模面,当系统到达滑模面时,姿态误差可以在有限时间内收敛,并利用二阶滑模趋近律设计控制器,保证系统在有限时间到达滑模面.在干扰观测器误差未完全收敛时,滑模控制器可以对存在的扰动进一步抑制,实现姿态跟踪系统的有限时间稳定,并通过李雅普诺夫方法严格证明了其稳定性.最后,仿真结果表明,干扰估计值误差可以在有限时间内收敛,证明了该控制方法对存在的干扰是具有较好的鲁棒性.     

基于super-twisting算法的多航天器姿态有限时间分布式协同控制

针对受外界干扰和执行器故障影响的多航天器姿态协同控制问题,本文设计了一种基于干扰观测器的分布式协同supper-twisting滑模控制器.首先,将各航天器的外界干扰和执行器故障看作一个集总干扰,设计自适应滑模干扰观测器对其进行估计.其次,将supper-twisting算法和积分滑模面相结合,设计一种基于多航天器姿态一致性误差的分布式协同控制器,并由Lyapunov稳定性理论证明了所设计的多航天器姿态可以在有限时间内收敛到平衡点附近的邻域内.最后的仿真研究及比较结果表明,所设计的控制器可以加快系统的收敛速度,并提高系统的控制精度.     

存在飞轮安装偏差与故障的卫星姿态容错控制

基于滑模控制理论提出一种刚体卫星姿态稳定控制方法,实现对反作用飞轮部分失效故障的容错控制,以及对其安装偏差的补偿控制,并从理论上证明了所设计的控制器在有限时间内能够实现对闭环姿态控制系统的几乎全局渐近稳定控制.最后将所设计的控制器应用于某型卫星姿态稳定任务,仿真结果验证了所提出方法的有效性.     

基于动态控制分配的卫星姿态控制系统容错控制

针对卫星姿态控制系统执行机构故障情况下的姿态跟踪问题,研究了一种基于动态控制分配的容错控制方法。首先,考虑由卫星转动惯量不确定性与外界干扰组成复合干扰,设计了基于干扰观测器的反步姿态跟踪控制器,利用干扰观测器对复合干扰进行估计,并且采用李雅普诺夫方法分析了闭环系统的稳定性;其次,针对发生乘性执行机构故障的卫星姿态控制系统,设计了基于动态控制分配的容错控制方法,该方法无需对控制律进行调整,而是利用故障信息调整目标函数,通过动态控制分配方法实现容错控制。仿真结果表明,该方法能够在执行机构发生故障情况下有效完成姿态跟踪。     

基于动态控制分配的卫星姿态控制系统容错控制北大核心CSCD

针对卫星姿态控制系统执行机构故障情况下的姿态跟踪问题,研究了一种基于动态控制分配的容错控制方法。首先,考虑由卫星转动惯量不确定性与外界干扰组成复合干扰,设计了基于干扰观测器的反步姿态跟踪控制器,利用干扰观测器对复合干扰进行估计,并且采用李雅普诺夫方法分析了闭环系统的稳定性;其次,针对发生乘性执行机构故障的卫星姿态控制系统,设计了基于动态控制分配的容错控制方法,该方法无需对控制律进行调整,而是利用故障信息调整目标函数,通过动态控制分配方法实现容错控制。仿真结果表明,该方法能够在执行机构发生故障情况下有效完成姿态跟踪。     

飞翼无人机复合连续非奇异终端滑模姿态跟踪容错控制

本文针对受多源干扰和舵面故障影响的飞翼无人机系统姿态跟踪控制问题进行研究, 提出了一种基于高阶滑模观测器的复合连续非奇异终端滑模主动抗干扰容错控制算法, 在实现姿态跟踪误差有限时间收敛的同时, 保证了控制量的连续. 并且针对控制力矩的具体实现问题, 结合飞翼无人机气动舵面冗余特性, 给出了基于加权伪逆算法的舵面分配方案, 该方案在满足舵面约束的情况下, 保证了舵面偏转角度的最优. 仿真结果表明, 所提控制方案显著提升了飞翼无人机姿态跟踪精度和跟踪误差的收敛速度, 并且保证了所有舵面满足偏角约束.     

Third‐order sliding mode fault‐tolerant control for satellites based on iterative learning observer

The attitude fault‐tolerant control problem for a satellite with reaction‐wheel failures, uncertainties, and unknown external disturbances is investigated in this paper. Firstly, an iterative learning observer (ILO) is proposed to achieve fault detection, isolation, and estimation. Secondly, based on the ILO, a third‐order sliding mode controller is proposed to stabilize the satellite attitude rapidly under unknown external disturbances and reaction‐wheel faults. Thirdly, the asymptotically stability of the ILO and the third‐order sliding mode controller is proved by using the Lyapunov stability theory. Finally, simulation results demonstrate that the proposed control scheme is more effective and feasible by comparing with other fault‐tolerant control approach.     

飞轮安装偏差的过驱动航天器有限时间姿态控制

针对反作用飞轮安装存在偏差的过驱动航天器姿态跟踪问题, 提出一种有限时间姿态补偿控制策略. 通过设计自适应滑模控制器保证实现对不确定性转动惯量与外部干扰的鲁棒控制, 同时实现对飞轮安装偏差的补偿控制, 并应用Lyapunov 稳定性理论证明了该控制器能够在有限时间内实现姿态跟踪控制. 最后, 将该控制器应用于某型航天器的姿态跟踪控制, 仿真结果验证了所提出方法的有效性.     

Nonsingular terminal sliding mode based finite-time control for spacecraft attitude tracking

This paper studies finite-time attitude tracking control problem of a rigid spacecraft system with external disturbances and inertia uncertainties. Firstly, a new finite-time attitude tracking control law is designed using nonsingular terminal sliding mode concepts. In the absence and presence of external disturbances and inertia uncertainties, this controller can drive the attitude and angular velocity tracking errors to reach zero in finite time. Secondly, a finite-time disturbance observer is introduced to estimate the disturbance, and a composite controller is developed which consists of a feedback control based on nonsingular terminal sliding mode method and compensation term based on finite-time disturbance observer. Finite-time convergence of attitude tracking errors and the stability of the closed-loop system is ensured by the Lyapunov approach. Numerical simulations on attitude control of spacecraft are also given to demonstrate the performance of the proposed controllers.     

Robust Fault‐Tolerant Control of Launch Vehicle Via GPI Observer and Integral Sliding Mode Control

A robust fault‐tolerant attitude control scheme is proposed for a launch vehicle (LV) in the presence of unknown external disturbances, mismodeling dynamics, actuator faults, and actuator's constraints. The input‐output representation is employed to describe the rotational dynamics of LV rendering three independently decoupled second order single‐input‐single‐output (SISO) systems. In the differential algebraic framework, general proportional integral (GPI) observers are used for the estimations of the states and of the generalized disturbances, which include internal perturbations, external disturbances, and unknown actuator failures. In order to avoid the defects of the conventional sliding surface, a new nonlinear integral sliding manifold is introduced for the robust fault‐tolerant sliding mode controller design. The stability of the GPI observer and that of the closed‐loop system are guaranteed by Lyapunov's indirect and direct methods, respectively. The convincing numerical simulation results demonstrate the proposed control scheme is with high attitude tracking performance in the presence of various disturbances, actuator faults, and actuator constraints.     

充液航天器的鲁棒固定时间终端滑模容错控制

本文以三轴稳定充液航天器为研究背景,在其进行姿态机动控制过程中充分考虑了外部未知干扰、参数不确定、执行器故障和控制输入饱和等因素的影响,提出了一种固定时间终端滑模控制策略.动力学建模过程中,利用粘性球摆等效力学模型模拟液体燃料小幅晃动,通过拉格朗日方程推导出航天器的耦合动力学模型.姿态控制器设计过程中,首先构造固定时间滑模面,使其稳定到平衡位置的时间与系统初始状态无关.然后采用固定时间控制理论结合自适应估计算法提出了自适应固定时间容错控制律,其中自适应算法用于估计系统集总扰动的未知上界.所提出的控制策略采用饱和函数克服终端滑模控制方案中存在的奇异性问题,同时保证系统状态快速收敛到固定时间滑模面.根据Lyapunov稳定性理论证明了系统状态能够在固定时间内收敛到原点的较小邻域内.对比的数值仿真方法验证了本文提出控制方法的有效性和鲁棒性.     

Finite-time attitude tracking control for a rigid spacecraft using time-varying terminal sliding mode techniques

This paper investigates the finite-time attitude tracking control for a rigid spacecraft in the presence of inertia uncertainties and external disturbances. Two novel time-varying terminal sliding mode control algorithms are derived for attitude tracking control system. The proposed two control algorithms not only eliminate the reaching phase of the conventional sliding mode control but also guarantee the tracking errors converge to zero in finite time. Moreover, the singularity problem can be avoided. Simulation results are provided to demonstrate the effectiveness of the proposed design methods.     

Distributed fault‐tolerant control design for spacecraft finite‐time attitude synchronization

This paper develops two distributed finite‐time fault‐tolerant control algorithms for attitude synchronization of multiple spacecraft with a dynamic virtual leader in the presence of modeling uncertainties, external disturbances, and actuator faults. The leader gives commands only to a subset of the followers, and the communication flow between followers is directed. By employing a novel distributed nonsingular fast terminal sliding mode and adaptive mechanism, a distributed finite‐time fault‐tolerant control law is proposed to guarantee all the follower spacecraft that finite‐time track a dynamic virtual leader. Then utilizing three distributed finite‐time sliding mode estimators, an estimator‐based distributed finite‐time fault‐tolerant control law is proposed using only the followers' estimates of the virtual leader. Both of them do not require online identification of the actuator faults and provide robustness, finite‐time convergence, fault‐tolerant, disturbance rejection, and high control precision. Finally, numerical simulations are presented to evaluate the theoretical results. Copyright © 2015 John Wiley & Sons, Ltd.     

Adaptive finite‐time attitude stabilization for rigid spacecraft with actuator faults and saturation constraints

The attitude stabilization problem for rigid spacecraft in the presence of inertial uncertainties, external disturbances, actuator saturations, and actuator faults is addressed in this paper. First, a novel fast terminal sliding mode manifold is designed to avoid the singularity problem while providing high control ability. In addition, fast terminal sliding mode control laws are proposed to make the spacecraft system trajectory fast converge onto the fast terminal sliding mode surface and finally evolve into small region in finite time, which cannot be achieved by the previous literatures. Based on the real sliding mode context, a practical adaptive fast terminal sliding mode control law is presented to guarantee attitude stabilization in finite time. Also, simulation results are presented to illustrate the effectiveness of the control strategies. Copyright © 2015 John Wiley & Sons, Ltd.