Trajectory-based design of robust non-fragile controllers for a class of uncertain linear continuous-time systems

This paper deals with a design problem of robust non-fragile stabilizing controllers for a class of uncertain linear continuous-time systems. The proposed design approach of robust non-fragile controllers is based on computation of the trajectory for the uncertain linear system and differs from the existing methods based on quadratic stabilization via Lyapunov criterion. In this paper, we show that sufficient conditions for asymptotical stability of the linear system with uncertainties and controller gain variations, and a LMI-based design algorithm of a robust non-fragile controller. Furthermore, we extend the result to the design problem of decentralized robust non-fragile controllers for a class of uncertain large-scale interconnected systems. Finally, the effectiveness of the proposed design scheme of robust non-fragile controllers is shown through illustrative examples.     

On decentralised control of non-linear interconnected systems

The asymptotic stabilisation problem of a class of large-scale interconnected systems is considered, where the non-linear interconnections between subsystems satisfy quadratic constraints that are functions of the whole system's state vector. A decentralised combined observer-controller compensator is proposed and analysed, where the subsystems’ state vectors are estimated using local sliding mode observers. The closed-loop system driven by the proposed decentralised compensator is guaranteed to be asymptotically stable subject to two conditions that are easily verifiable. Simulation results illustrate the effectiveness of the proposed decentralised combined observer-controller compensator.     

SISO线性系统的滑模变结构状态范数控制

在线性系统滑模控制理论的基础上,给出了对于一般SLSO线性系统状态范数控制的形式,提出了状态范数的控制器结构。基于李亚普诺夫稳定性理论证明了状态范数控制系统的闭环稳定性。然后分别针对状态范数控制器与趋近率控制和单位向量控制进行了数值仿真的分析与比较,结果说明状态范数控制综合了趋近率控制和单位向量控制各自的优点,控制信号抖振更小,闭环系统稳态性能有了一定改进。     

Second‐order sliding mode controller design subject to mismatched unbounded perturbations

The dynamics of the second‐order sliding mode (SOSM) can be obtained by directly taking the second derivative on the sliding variable when it has a relative degree of 2 with respect to the control input. However, there will always appear some state‐dependent certain or uncertain terms in the first derivative of the sliding variable, and the derivative directly imposed on these terms could enlarge the uncertainties in the control channel. One method to reduce the uncertainties in the control channel is to hold this information in the dynamics of the first derivative of the sliding variable, while the original SOSM dynamics could be transformed to be a SOSM system with a mismatched unbounded perturbation. This paper focuses on the controller design problem for SOSM dynamics subject to mismatched unbounded perturbation. By using Lyapunov analysis, a novel backstepping‐like design methodology will be proposed. The rigorous mathematical proof will show that under the derived SOSM controller, the closed‐loop sliding mode dynamics is globally finite‐time stable. Meanwhile, the frequently used constant upper bound assumptions for the standard SOSM system can also be extended to the state‐dependent hypotheses in this paper. An academic example is illustrated to verify the effectiveness of the proposed method. Copyright © 2017 John Wiley & Sons, Ltd.     

不确定离散时间系统的滑模可靠控制

存在状态时滞的不确定离散时间系统的的滑模可靠控制问题,其中,被控系统执行器可能发生部分故障.通过构造一种拟积分型切换面,可以保证系统状态轨迹从开始时刻就位于切换面上.利用Lyapunov稳定性理论和线性矩阵不等式技术给出了滑模动态系统渐近稳定的充分条件.而且,所设计的滑模控制律可以保证在执行器故障影响下的滑动模态仍然是可达的.数值仿真验证了本文设计方法的有效性.     

不确定输入时滞系统的滑模输出反馈控制

研究了在状态不可测,并且状态参数和控制输入矩阵同时存在不确定性的情况下,不确定输入时滞系统的滑模控制问题.为了有效克服不确定性和时滞对系统稳定性的影响,在状态估计空间选择了一种积分型的切换函数,设计了一种基于状态观测器的滑模控制器,并证明了所设计切换面的可达性.通过李亚普诺夫理论,给出了闭环系统渐近稳定的充分条件.数值仿真验证了算法的有效性.     

LTE小区搜索中一种新的SSS检测算法

主要研究了SSS检测, 提出一种新的SSS检测算法。该算法首先利用滑动平均窗修正接收的PSS处估计出的信道频率响应, 并用修正后的信道频率响应对接收的SSS序列进行信道补偿; 其次, 算法对信道补偿后的序列进行实数提取操作, 消除虚部数据干扰; 最后算法联合两个连续的SSS接收序列进行检测进一步提高检测性能。TDD和FFD两种模式下的仿真结果表明：该算法可以较好地实现SSS检测且比现有几种SSS检测算法在低信噪比（SNR<0 dB）条件下具有更好的检测性能。     

Adaptive sliding mode control for MIMO nonlinear systems based on fuzzy logic scheme

In this study an indirect adaptive sliding mode control (SMC) based on a fuzzy logic scheme is proposed to strengthen the tracking control performance of a general class of multi-input multi-output (MIMO) nonlinear uncertain systems. Combining reaching law approach and fuzzy universal approximation theorem, the proposed design procedure combines the advantages of fuzzy logic control, adaptive control and sliding mode control. The stability of the control systems is proved in the sense of the Lyapunov second stability theorem. Two simulation studies are presented to demonstrate the effectiveness of our new hybrid control algorithm.     

宏/微驱动定位系统滑模变结构控制的研究

研究了具有宏/微双重驱动定位工作台的滑模变结构控制技术.该工作台采用直线电机进行大行程位移驱动,来保证较大的工作行程和较快的响应速度,采用压电陶瓷微位移器完成精密位移驱动,利用光栅尺实现闭环位移反馈,可以实现100mm的工作行程,0.01μm的重复定位精度.     

高速动车组强耦合模型的分布式滑模控制策略

高速动车组是由多节车辆与钩缓装置链接而成的复杂系统. 将钩缓装置等效成弹簧 − 阻尼器系统, 分析动车组运行过程中钩缓装置对相邻车辆作用的动力学机理, 明确作用方式, 建立高速动车组的强耦合模型. 根据列车模型动力或制动力输入的分散特征, 设计分布式神经网络滑模控制策略, 对高速动车组进行速度跟踪控制. 为减小速度跟踪过程中未知因素对高速动车组控制精度的影响, 利用列车历史运行数据, 采用历史工况数据中心对当前控制律输出进行补偿以提高控制精度与实用稳定性. 采用高速动车组运行仿真平台的仿真实验结果表明, 该建模方法较以往多质点模型更能体现高速动车组运行特性, 且采用补偿规则的控制策略优于传统控制效果.