求解离散优化问题的元胞量子狼群演化算法

针对离散空间优化问题,提出了求解离散优化问题的元胞量子狼群演化算法,首先,为了提高算法的全局收敛速度,采用双策略量子位初始化方法和滑模交叉方法,分别生成量子狼群初始位置和产生头狼,实现种群多样性;其次,为了描述头狼与猎物间的距离以及增强狼群的遍历范围,采用二进制编码方式和元胞自动机中的演化规则,分别实现狼群中个体狼与猎物距离的精确描述和量子旋转角的选取调整;然后,为了证明该算法的收敛性能,采用泛函分析方法,实现了算法全局收敛性能的验证;最后,通过6个标准测试函数的仿真实验,并与狼群算法以及量子狼群算法的优化结果进行比较。实验结果表明,该算法具有较快的收敛速度和较好的全局寻优能力。     

A fast non-singular terminal sliding mode control based on perturbation estimation for piezoelectric actuators systems

Piezoelectric actuators (PEAs) are the key devices in micro/nano positioning system. However, the PEA performance is significantly degraded by the inherent non-linear behaviour. This behaviour is a consequence of the hysteresis properties contained within PEAs. Therefore, in micro/nano positioning applications, a robust control system has to be adopted for such actuators. This paper proposes a systematic control method that utilises a fast non-singular terminal sliding mode (FNTSM) based on online perturbation estimation technique for PEAs. Unlike other sliding mode methods, the FNTSM control method is characterised by chatter free. Besides, a zero error convergence can be guaranteed in finite time in the presence of disturbance and system uncertainties (i.e., hysteresis and gain changes). The design of the FNTSM control based on perturbation estimation (FNTSMPE) is presented. A model-free robust exact differentiator is used to estimate the states of the feedback system from merely measurable position signal. Theoretical analysis and the experimental results of FNTSMPE control reveal that high-precision and robust performance is achieved in comparison with ordinary FNTSM control.     

Model-independent position domain sliding mode control for contour tracking of robotic manipulator

In this paper, a new position domain feedback type sliding mode control (PDC-SMC) law is proposed for contour tracking control of multi-DOF (degree of freedom) nonlinear robotic manipulators focusing on the improvement of contour tracking performances. One feature of the proposed control law is its model-independent control scheme that can avoid calculation of the feedforward part in a standard SMC. The new control law takes the advantages of the high contour tracking performance of PD type feedback position domain control (PDC) and the robustness of SMC. Stability analysis is performed using the Lyapunov stability theory, and simulation studies are conducted to verify the effectiveness of the developed PDC-SMC control system. In addition, the effects of control parameters of the SMC on system performances are studied.     

Sliding mode control-based linear functional observers for discrete-time stochastic systems

Sliding mode control (SMC) is one of the most popular techniques to stabilise linear discrete-time stochastic systems. However, application of SMC becomes difficult when the system states are not available for feedback. This paper presents a new approach to design a SMC-based functional observer for discrete-time stochastic systems. The functional observer is based on the Kronecker product approach. Existence conditions and stability analysis of the proposed observer are given. The control input is estimated by a novel linear functional observer. This approach leads to a non-switching type of control, thereby eliminating the fundamental cause of chatter. Furthermore, the functional observer is designed in such a way that the effect of process and measurement noise is minimised. Simulation example is given to illustrate and validate the proposed design method.     

Positive sliding mode control for blood glucose regulation

Biological systems involving positive variables as concentrations are some examples of so-called positive systems. This is the case of the glycemia–insulinemia system considered in this paper. To cope with these physical constraints, it is shown that a positive sliding mode control (SMC) can be designed for glycemia regulation. The largest positive invariant set (PIS) is obtained for the insulinemia subsystem in open and closed loop. The existence of a positive SMC for glycemia regulation is shown here for the first time. Necessary conditions to design the sliding surface and the discontinuity gain are derived to guarantee a positive SMC for the insulin dynamics. SMC is designed to be positive everywhere in the largest closed-loop PIS of plasma insulin system. Two-stage SMC is employed; the last stage SMC2 block uses the glycemia error to design the desired insulin trajectory. Then the plasma insulin state is forced to track the reference via SMC1. The resulting desired insulin trajectory is the required virtual control input of the glycemia system to eliminate blood glucose (BG) error. The positive control is tested in silico on type-1 diabetic patients model derived from real-life clinical data.     

基于微粒群算法的重力坝坝基多滑面稳定可靠度分析

以往混凝土重力坝坝基抗滑稳定可靠度分析大多只研究单滑面或双滑面的情形,但通常的地质条件下,基岩内可能存在多滑面失稳,目前关于重力坝多滑面抗滑稳定可靠度的研究成果相对较少。本文在刚体极限平衡等安全系数法的基础上,提出了基于微粒群算法的重力坝坝基深层多滑面抗滑稳定可靠度计算方法,该方法能够处理非线性隐式功能函数的可靠指标计算问题,即根据可靠指标的几何涵义,将可靠度计算转化为约束优化问题,从而实现智能优化计算。3个算例分析表明,该方法计算工作量少,精度和计算效率高,算法适用性广,能够应用到复杂的坝基多滑面抗滑稳定可靠度计算中。工程实例分析表明,该方法具有较高的实用价值,可为重力坝稳定安全评价方法的深入研究与重力坝结构设计提供新的思路和技术支撑。     

大型超深竖井滑模结构设计优化及安装施工——以巴基斯坦N-J水电工程为例

巴基斯坦N-J水电工程调压竖井井壁衬砌采用滑模施工。为进一步提高滑模施工的安全性、可靠性及混凝土衬砌质量,降低劳动强度,对滑模的下料系统、模板系统进行了优化改造,并从多角度比较分析了不同施工方案的优劣。滑模生产实际及受力有限元分析结果表明,其结构强度满足施工要求。此外,通过方案对比分析,介绍了该工程采用的竖井底部安装技术,可为相关工程提供参考。     

改进滑模模型参考自适应的PMSM无传感控制

针对MRAS（模型参考自适应）观测器对PMSM（永磁同步电机）参数变化和外部干扰敏感的缺点,设计了一种用于PMSM无传感控制的软开关滑模模型参考自适应观测器。该观测器将滑模控制与MRAS相结合,并构造了边界层可变的正弦饱和函数,以抑制由于滑模控制引起的系统抖动,增强系统鲁棒性。同时引入sigmoid函数,以提高滑模软切换速度控制器的稳定性。实验仿真结果表明,软开关滑模模型参考自适应控制不仅可以实现边界层内的快速收敛、弱化抖动,而且跟踪能力强。     

地震条件下亭子口重力坝深层滑动失稳模式研究（研究生论坛）

深层抗滑稳定是重力坝设计中的关键性问题,深层滑动失稳模式的确定是深层抗滑稳定问题分析的重要环节。目前地震条件下重力坝深层滑动失稳模式研究成果较少,且静力条件下较常用的处理方案中对滑移失稳模式的确定为定性方法,较依赖于工程经验。基于此研究现状,以亭子口重力坝为工程背景,本文采用了以静力条件下大坝深层滑动失稳模式为基础,综合模型试验与数值分析、定量分析与定性分析成果的研究方法,深入分析了地震条件下重力坝深层滑动失稳模式。获得地震条件下重力坝深层滑动三种可能的失稳模式,并结合局部稳定安全系数与整体稳定安全系数对各可能滑动失稳模式安全储备有较准确的认识。