并联式运载器上升段广义超螺旋有限时间控制

针对受模型不确定和外部干扰影响的并联式运载器上升段姿态控制问题, 提出了一种基于广义超螺旋算法的自适应滑模有限时间控制方法。首先, 将姿态跟踪控制问题转化为跟踪误差系统的镇定问题, 建立了面向控制的模型。其次, 将单输入单输出(single input single output, SISO)固定时间广义超螺旋算法拓展应用到多输入多输出(multiple input multiple output, MIMO)耦合非线性系统上, 基于该算法设计了固定时间状态观测器和自适应滑模有限时间控制器, 利用Lyapunov稳定性理论证明了闭环系统的有限时间稳定特性。最后, 通过与传统比例-微分(proportional and differential, PD)控制器仿真对比, 验证了该方法具有更优的控制精度和鲁棒性。     

一类非完整系统的有限时间镇定控制

针对一类可化为链式标准型的非完整系统的有限时间镇定问题,提出了一种基于切换控制策略的有限时间镇定控制器,并给出了控制器参数的选择条件。该控制器利用切换控制的思想,根据系统的状态变化,通过有限次切换,可使得非完整链式系统各状态在有限时间内从任意的非平衡位置收敛至平衡位置。最后给出了应用该控制器控制非完整链式系统的具体形式,通过仿真实验验证了所设计的有限时间镇定控制器的有效性。     

Robust Finite-Time Guaranteed Cost Control for Positive Systems with Multiple Time Delays

This paper deals with the finite-time guaranteed cost control problem for positive system with multiple time delays and bounded disturbance. By using Lyapunov-Krasovskii functional method,some new sufficient conditions for the design of a state feedback controller which makes the closedloop system finite-time stable and guarantees an adequate cost level of performance are derived. Two numerical examples are also given to show the effectiveness of the proposed method.     

基于自适应快速终端滑模的航天器容错控制

针对执行机构发生故障时的航天器姿态控制问题,提出了一种基于自适应快速终端滑模的容错控制设计方法。该方法通过选择具有快速终端特性的滑模面,提高航天器容错控制的收敛速率,实现系统有限时间稳定|利用自适应控制方法在线调整控制器参数,消除对故障最小 值信息的依赖。仿真结果表明,与基于普通滑模控制器的容错控制相比,所提出的方法在保证系统鲁棒性和稳定性的同时,三轴姿态角和态角速度收敛时间可分别降低约54.5%和50%,实现快速有效的航天器容错控制。     

Finite-time tracking control for motor servo systems with unknown dead-zones

A finite-time tracking control scheme is proposed in this paper based on the terminal slid- ing mode principle for motor servo systems with unknown nonlinear dead-zone inputs. By using the differential mean value theorem, the dead-zone is represented as a time-varying system and thus the inverse compensation approach is avoided. Then, an indirect terminal sliding mode control （ITSMC） is developed to guarantee the finite-time convergence of the tracking error and to overcome the singu- larity problem in the traditional terminal sliding mode control. In the proposed controller design, the unknown nonlinearity of the system is approximated by a simple sigmoid neural network, and the ap- proximation error is diminished by employing a robust term. Comparative experiments on a turntable servo system are conducted to show the superior performance of the proposed method.     

一类非线性系统的有限时间保成本控制

针对一类具有有限能量外部扰动的连续不确定非线性系统,讨论其有限时间保成本控制问题。首先采用Takagi-Sugeno模糊模型对非线性系统进行建模,然后找到一个合适的Lyapunov函数,给出闭环模糊系统有限时间有界的充分条件及有限时间保成本控制器的设计方法,并将控制器的求解转化为一组线性矩阵不等式的可行性问题。研究表明,采用该方法设计的控制器不仅能使闭环不确定模糊系统对所有可允许的外部扰动是有限时间有界的,而且还给出了保成本上界的一个优化值。最后,仿真结果表明该设计方法是有效的。     

基于SE(3)的航天器姿轨一体化有限时间容错控制

针对相对运动航天器,当执行机构出现故障以及外部干扰和系统不确定性同时存在的情形下,利用滑模控制的鲁棒性,提出了一种有限时间容错控制方法。基于李群SE(3)建立了单刚体航天器姿轨一体化模型,并在指数坐标下推导了相对运动航天器误差动力学方程。设计了一类非奇异快速终端滑模面,并采用等价自适应方法设计控制器估计和补偿外总扰动,提出的容错控制算法可以不依赖于故障诊断与检测环节。运用Lyapunov方法证明了系统在故障和扰动等多约束条件下的稳定性和有限时间快速收敛性,数值仿真结果分析也验证了该容错控制器的快速性、准确性与可靠性。     

多智能体系统的有限时间跟踪控制

基于领导-跟随者模型研究了多智能体系统的有限时间跟踪控制问题。针对领导者状态是时变的情况,提出了一类非线性有限时间跟踪控制算法,在固定网络拓扑结构下,利用Lyapunov有限时间稳定性理论和矩阵理论分析,得到了该算法使得系统中跟随者状态在有限时间内与领导者状态达到一致的充分条件;在切换网络拓扑结构下,提出了一类有限时间跟踪控制算法,在领导者的状态是时不变的情况下,给出了该算法使得系统实现有限时间跟踪控制的充分条件。仿真实例验证了所提出两类算法的有效性。     

Robust Finite-Time Trajectory Tracking Control of Wheeled Mobile Robots with Parametric Uncertainties and Disturbances

In this paper, a robust finite-time tracking control scheme is proposed for wheeled mobile robots with parametric uncertainties and disturbances. To eliminate the effect of lumped uncertainties,a nonlinear extended state observer(NESO) is employed to estimate the unknown states as well as uncertainties, and the corresponding coefficients are tuned via pole placement technique. Based on the observation values, the finite-time sliding mode controller is presented to guarantee that both the sliding mode variables and tracking errors converge to zero within finite time. Simulation results are given to demonstrate the effectiveness of the proposed control method.     

基于特征结构配置的结构主动控制及仿真

考虑了具有最优控制的结构主动控制问题,目的是在系统满足闭环特性的前提下,设计状态反馈控制器使得系统性能泛函极小化。利用特征结构配置方法提供的自由度,给出了性能泛函的显示参数化表示,从而该问题转化为带有约束条件的优化问题,参与优化的变量仅为一组参量。并给出了求解该优化问题的算法,该算法直接基于结构系统矩阵,故其简单性为工程应用提供方便。地震作用下对三层剪切结构建筑模型进行仿真分析,结果表明所提结构主动控制方法的有效性。     

高层建筑风振反应的T-S模糊控制

研究了高层建筑在顺风向脉动风荷载激励下T—S模糊控制问题。受控结构为拟建于澳大利亚Melboume的一幢钢筋混凝土结构办公楼，高306米，总共76层，控制设备为安装于结构最顶层的主动调谐质量阻尼器，主动控制力由T—S型模糊控制器求得。选取LQG控制的仿真结果为T—S模糊控制器的学习样本，采用减法聚类法和混合学习算法对T—S模型进行结构与参数辨识，通过改变结构刚度束检验模糊控制器的鲁棒性。仿真结果表明：T—S模糊控制器鲁棒性好，控制效果能够满足高层建筑风振舒适度的要求；与Mamdani型控制器相比，在线计算时间短，无计算时滞问题。     

Finite-Time Stability for Interval Type-2 Fuzzy Nonlinear Systems via an Observer-Based Sliding Mode Control

This work focuses on the design of a sliding mode controller for a class of continuous-time interval type-2 fuzzy-model-based nonlinear systems with unmeasurable state information over a finite-time interval. Aiming at describing the nonlinearities containing parameter uncertainties that inevitably appear in practice, the interval type-2 fuzzy sets are employed to model the studied system. To improve the designing flexibility, a fuzzy observer model non-parallel distribution compensation scheme is designed to estimate the state information of the plant, i.e., the observer is allowed to have a mismatching premise structure from the system. On this basis, the appropriate fuzzy sliding surface and fuzzy controller are constructed by following the same premise variables as the designed fuzzy observer. Then, by means of the sliding mode control theory and the Lyapunov function method, some novel sufficient criteria are established to ensure the finite-time boundedness for the studied systems via a partitioning strategy including the reaching phase, the sliding motion phase and the whole time interval. Furthermore, the designed gains are acquired by solving the matrix convex optimization problem. Finally, the effectiveness of the developed method is demonstrated by two simulation examples.

     

基于数据挖掘的结构模糊控制规则生成与仿真分析

结合智能控制与现代控制理论,在结构控制领域,提出了直接从已有主动控制算法的成功数据样本中提取模糊控制规则的思想和方法。以顶层设置AMD控制装置的五层钢框架模型结构为例,阐述了提取模糊控制规则的步骤,仿真结果证实了所设计的二输入单输出模糊控制器的有效性和鲁棒性。通过76层Benchmark风振模型的模糊控制仿真分析,进一步验证了这种充分利用主动控制算法获取模糊规则思想的有效性。研究成果使结构振动模糊控制器的设计具有一定的依据,为AMD模糊控制走向工程应用奠定了理论基础。     

Guaranteed Cost Finite-Time Control of Fractional-Order Nonlinear Positive Switched Systems with D-Perturbations via MDADT

This paper is concerned with the problem of guaranteed cost finite-time control of fractionalorder nonlinear positive switched systems(FONPSS) with D-perturbation. Firstly, the proof of the positivity of FONPSS with D-perturbation is given, the definition of guaranteed cost finite-time stability is firstly given in such systems. Then, by constructing linear copositive Lyapunov functions and using the mode-dependent average dwell time(MDADT) approach, a static output feedback controller is constructed, and sufficient conditions are derived to guarantee that the corresponding closed-loop system is guaranteed cost finite-time stable(GCFTS). Such conditions can be easily solved by linear programming. Finally, an example is provided to illustrate the effectiveness of the proposed method.     

Finite-time stability and stabilization of Markovian switching stochastic systems with impulsive effects

Many practical systems in physics,biology,engineering and information science exhibit impulsive dynamical behaviors due to abrupt changes at certain instants during the dynamical processes.The problems of finite-time stability analysis are investigated for a class of Markovian switching stochastic systems,in which exist impulses at the switching instants.Multiple Lyapunov techniques are used to derive sufficient conditions for finite-time stochastic stability of the overall system.Furthermore,a state feedback controller,which stabilizes the closed loop systems in the finite-time sense,is then addressed.Moreover,the controller appears not only in the shift part but also in the diffusion part of the underlying stochastic subsystem.The results are reduced to feasibility problems involving linear matrix inequalities (LMIs).A numerical example is presented to illustrate the proposed methodology.     

State and Output Feedback Finite-time Guaranteed Cost Control of Linear It Stochastic Systems

The problem of guaranteed cost control based on finite-time stability for stochastic system is first investigated in this paper.The motivation of solving this problem arises from an observation that finite/infinite-horizon guaranteed cost control does not consider the transient performance of the closed-loop system,but guaranteed cost control based on finite-time stability involves this practical requirement.In order to explain this problem explicitly,a concept of the stochastic finite-time guaranteed cost control is introduced,and then some new sufficient conditions for the existence of state and output feedback finite-time guaranteed cost controllers are derived,which guarantee finite-time stochastic stability of closed-loop systems and an upper bound of a quadratic cost function.Furthermore,this problem is reduced to a convex optimization problem with matrix inequality constraints and a new solving algorithm is given.Finally,an example is given to illustrate the effectiveness of the proposed method.     

Finite-time coordination control for formation flying spacecraft

This paper investigates a distributed coordination control scheme using an adaptive terminal sliding mode for formation flying spacecraft with coupled attitude and translational dynamics. In order to overcome the singularity of the traditional fast terminal sliding manifold, a novel fast terminal sliding manifold is given. And then, based on the adaptive control method, a continuous robust coordinated controller is designed to compensate external disturbances and to alleviate the chattering phenomenon. The theoretical analysis shows that the coordinated controller can guarantee the finite-time stability of the overall closed-loop system through local information exchange, and numerical simulations also demonstrate its effectiveness.     

Finite-time neural funnel control for motor servo systems with unknown input constraint

In this paper, a finite-time neural funnel control (FTNFC) scheme is proposed for motor servo systems with unknown input constraint. To deal with the non-smooth input saturation constraint problem, a smooth non-affine function of the control input signal is employed to approximate the saturation constraint, which is further transformed into an affine form according to the mean-value theorem. A fast terminal sliding mode manifold is constructed by using a novel funnel error variable to force the tracking error falling into a prescribe boundary within a finite time. Then, a simple sigmoid neural network is utilized to approximate the unknown system nonlinearity including the saturation. Different from the prescribed performance control (PPC), the proposed finite-time neural funnel control avoids using the inverse transformed function in the controller design, and could guarantee the prescribed tracking performance without knowing the saturation bounds in prior. The effectiveness and superior performance of the proposed method are verified by comparative simulation results.     

基于NTSM的航天器特征点凝视跟踪控制

针对航天器特征点凝视以及随动跟飞问题,提出了一种建立在目标特征点指向(feature point directing, FPD)坐标系下的相对运动动力学模型,并基于非奇异终端滑模方法(nonsingular terminal sliding mode, NTSM)实现了航天器的相对姿轨耦合控制。首先,以凝视跟踪的目标特征点为原点,跟踪指向轴为主轴,建立了FPD坐标系下的特征点相对运动模型,该模型在控制过程中可以保持特征点相对运动期望状态稳定不变,从而降低了末端约束的处理难度。其次,基于NTSM方法设计了一种有限时间控制律,并对其稳定性和滑模到达时间进行了分析,理论证明了该控制律满足Lyapunov稳定性条件,且系统能在有限时间内迅速收敛到平衡状态。最后,仿真结果表明FPD坐标系下的特征点相对运动模型以及NTSM控制律在求解特征点凝视跟踪问题上具有良好的性能和普适性,研究成果对空间在轨维护、空间操控以及深空小天体悬停着陆等具有一定的理论参考价值。     

多智能体系统的非光滑二阶一致性协议

针对二阶积分器多智能体系统,提出了一类非光滑一致性协议设计方法。首先,基于反步设计方法,将速度看成虚拟控制量,并设计虚拟速度,使得状态一致性可以渐近达到。然后,基于有限时间控制方法设计控制律使得真实速度在有限时间内跟踪上虚拟速度。该控制律使得:当系统不存在外部扰动时,一致性可以渐近达到;当系统存在外部扰动时,任意两个智能体间的稳态误差渐近收敛到原点附近的一个小邻域内。仿真结果表明了该方法的有效性。