Lag Synchronization in Nonlinear Systems Based on Adaptive Control

Active control is an effective method for synchronizing two identical chaotic systems. However, this method works only for a certain class of chaotic systems with known parameters. An improvement method was proposed in order to overcome this limitation in this paper. A classical example was used to demonstrate the method. Finally, numerical examples were given to validate the efficiency of the method.

Boundary Control Problem of Infinite Order Distributed Hyperbolic Systems Involving Time Lags

Various optimal boundary control problems for linear infinite order distributed hyperbolic systems involving constant time lags are considered. Constraints on controls are imposed. Necessary and sufficient optimality conditions for the Neumann problem with the quadratic performance functional are derived.

Successive lag cluster consensus on multi-agent systems via delay-dependent impulsive control

We introduce a new consensus pattern, named a successive lag cluster consensus(SLCC), which is a generalized pattern of successive lag consensus(SLC). By applying delay-dependent impulsive control, the SLCC of first-order and second-order multi-agent systems is discussed. Furthermore, based on graph theory and stability theory, some sufficient conditions for the stability of SLCC on multi-agent systems are obtained. Finally, several numerical examples are given to verify the correctness of our theoretical results.

Robust lag synchronization between two different chaotic systems via dual-stage impulsive control

In this paper, an improved impulsive lag synchronization scheme for different chaotic systems with parametric uncertainties is proposed. Based on the new definition of synchronization with error bound and a novel impulsive control scheme （the so-called dual-stage impulsive control）, some new and less conservative sufficient conditions are established to guarantee that the error dynamics can converge to a predetermined level, which is more reasonable and rigorous than the existing results. In particular, some simpler and more convenient conditions are derived by taking the same impulsive distances and control gains. Finally, some numerical simulations for the Lorenz system and the Chen system are given to demonstrate the effectiveness and feasibility of the proposed method.

An improved impulsive control approach to robust lag synchronization between two different chaotic systems

In this paper, a novel robust impulsive lag synchronization scheme for different chaotic systems with parametric uncertainties is proposed. Based on the theory of impulsive functional differential equations and a new differential inequality, some new and less conservative sufficient conditions are established to guarantee that the error dynamics can converge to a predetermined region. Finally, some numerical simulations for the Lorenz system and Chen system are given to demonstrate the effectiveness and feasibility of the proposed method. Compared with the existing results based on so-called dual-stage impulsive control, the derived results reduce the complexity of impulsive controller, moreover, a larger stable region can be obtained under the same parameters, which can be shown in the numerical simulations finally.

考虑时变参考和转向延迟的自动驾驶车辆轨迹跟踪控制方法

最优控制方法已成为自动驾驶横向运动控制的主流研究和工业部署方法。LQR方法拥有在线计算量小、实时性好等优点而被广泛使用,但是无法考虑时变参考和转向延迟。延时的存在会导致LQR方法在高速时失去稳定性,因此在解决该问题的同时维持LQR小计算量的特性十分必要。本文在保证实时性的前提下,解决了LQR无法考虑时变参考和转向延迟的问题。将道路曲率作为时变参考、转向延迟特性作为纯延时和1阶惯性环节考虑进跟踪误差状态方程中,将控制时域对应的KKT逆矩阵部分查表到实时求解器中,旨在减小计算量并保证控制器的实时性。仿真试验结果表明:所搭建的EqLPV-MPC控制器可以有效处理道路变曲率工况;相比于LQR方法,车速为72 km/h的双移线工况下横向误差降低39%,航向角误差下降52%,质心侧偏角减少28%。实车试验结果表明,在双移线工况下,本文所搭建的控制器可以将最大横向误差控制在0.1 m以内。

注意瞬脱中Lag-1节省现象的加工机制

Lag-1节省现象强调短时注意加工的持续性进程。解释Lag-1节省现象的主要理论包括关门延缓假设、两阶段竞争理论、暂时性失控理论和推动反弹理论。关门延缓假设和暂时性失控理论分别强调Lag-1节省现象产生的时间决定因素与位置决定因素;关门延缓假设和两阶段竞争模型强调资源有限性,暂时性失控理论和推动反弹理论则关注调注意控制的作用。这些理论均强调注意资源或注意控制系统对目标刺激加工选择的重要性。未来研究可更多关注与注意转换机制等方面的结合。

A practical approach to robust impulsive lag synchronization between different chaotic systems

In this paper, a practical impulsive lag synchronization scheme for different chaotic systems with parametric uncertainties is proposed. By virtue of the new definition of synchronization and the theory of impulsive differential equations, some new and less conservative sufficient conditions are established to guarantee that the error dynamics can converge to a predetermined level. The idea and approach developed in this paper can provide a more practical framework for the synchronization between identical and different chaotic systems in parameter perturbation circumstances. Simulation results finally demonstrate the effectiveness of the method.

Real-time quality control of data from Sea-Wing underwater glider installed with Glider Payload CTD sensor

Profiles observed by Sea-Wing underwater gliders are widely applied in scientific research. However, the quality control(QC) of these data has received little attention. The mismatch between the temperature probe and conductivity cell response times generates erroneous salinities, especially across a strong thermocline. A sensor drift may occur owing to biofouling and biocide leakage into the conductivity cell when a glider has operated for several months. It is therefore critical to design a mature real-time QC procedure and develop a toolbox for the QC of Sea-Wing glider data. On the basis of temperature and salinity profiles observed by several Sea-Wing gliders each installed with a Sea-Bird Glider Payload CTD sensor, a real-time QC method including a thermal lag correction, Argo-equivalent real-time QC tests, and a simple post-processing procedure is proposed. The method can also be adopted for Petrel gliders.

Adaptive generalized matrix projective lag synchronization between two different complex networks with non-identical nodes and different dimensions

The adaptive generalized matrix projective lag synchronization between two different complex networks with non-identical nodes and different dimensions is investigated in this paper. Based on Lyapunov stability theory and Barbalat＇s lemma, generalized matrix projective lag synchronization criteria are derived by using the adaptive control method. Furthermore, each network can be undirected or directed, connected or disconnected, and nodes in either network may have identical or different dynamics. The proposed strategy is applicable to almost all kinds of complex networks. In addition, numerical simulation results are presented to illustrate the effectiveness of this method, showing that the synchronization speed is sensitively influenced by the adaptive law strength, the network size, and the network topological structure.

Successive lag synchronization on dynamical networks with communication delay

In this paper, successive lag synchronization （SLS） on a dynamical network with communication delay is investigated. In order to achieve SLS on the dynamical network with communication delay, we design linear feedback control and adaptive control, respectively. By using the Lyapunov function method, we obtain some sufficient conditions for global stability of SLS. To verify these results, some numerical examples are further presented. This work may find potential applications in consensus of multi-agent systems.

Jet lag

Nowadays,it is possible to travel to distant parts of the globe in several hours.This can result in the traveler ending up in a part of the world where time is different from his or her own"body clock",which controls our sleep patterns.If we travel east or west by more than four time zones(hours)then we will usually be affected.In the past when people traveled by sea,there

环境补贴能提升企业碳绩效吗--基于A股上市公司实证分析

环境补贴既是国家实现“双碳”目标的宏观调控手段,也是减轻企业环保负担、引导企业节能减排的推动力。选取2014~2019年接受环境补贴的1094家A股上市公司3735个观测值作为研究样本,采用双向固定效应模型,实证探究环境补贴对企业碳绩效的影响。研究表明,环境补贴与企业碳绩效显著正相关且具有滞后性特征,异质性检验发现,成立时间长的企业、国有企业、东部地区与中低污染企业环境补贴作用效果显著;进一步研究发现,环境补贴中的节能减排补贴与企业碳绩效显著正相关,环境治理补贴对企业碳绩效起负向作用。据此,提出环境补贴应以降碳为重点、减污降碳协同增效为目的等建议。

基于能量函数和改进虚拟同步控制的低频振荡抑制策略

随着可再生能源发电的普及和电力电子设备装机规模的扩大,电网稳定性显著降低,虚拟同步发电机(VSG)技术近年来备受关注。然而,VSG与同步发电机并网受到扰动时,VSG虚拟转子转速会发生突变,从而引起系统输出大幅度波动。为了抑制这些波动,本文提出一种基于超前滞后控制环的附加功率和惯量的VSG控制方法。通过引入能量函数的概念,得到一种新的控制策略。利用能量函数,分析VSG参数对系统低频振荡的影响,并通过调节VSG参数实现对VSG输出能量的控制,减少VSG与系统之间的能量流动,进而更好地抑制可再生能源发电系统的低频振荡。通过Matlab/Simulink和远宽半实物仿真平台证明了所提策略对可再生能源发电系统低频振荡具有良好的抑制效果。

基于非周期间歇控制的惯性神经网络同步/滞后同步

主要研究了惯性神经网络在非周期间歇控制下的同步/滞后同步问题.基于非降阶方法,利用Lyapunov方法、微分不等式技巧等,得出了在非周期间歇控制下惯性神经网络同步/滞后同步的充分判据,这种方法在实际应用中更具有可行性.最后,通过数值仿真验证理论结果的可行性.

二自由度磁浮列车悬浮系统时滞控制研究

为研究控制器时滞对磁浮列车悬浮系统稳定性的影响,首先,以位移-速度为反馈控制参数,建立考虑控制器时滞的二自由度磁浮列车悬浮系统模型;其次,通过Routh-Hurwitz稳定性判据得到无时滞系统的稳定性区域,同时,依据特征根穿越虚轴边界条件,获得系统发生Hopf分岔的控制器时滞临界值;最后,分析反馈控制参数及系统参数与控制器时滞临界值的关系.研究结果表明:当系统参数一定时,控制器时滞临界值随位移控制增益的增大而减小,随速度控制增益的增大先增大后减小;当反馈控制参数一定时,控制器时滞临界值随二系刚度的增大而减小,随二系阻尼的增大而增大;当系统时滞以10^(−6)数量级在时滞临界值附近渐渐增大时,系统会从稳定—周期运动—不稳定逐渐变化,期间发生超临界Hopf分岔.

提升重型车辆起步性能协调控制策略

针对重型车辆起步响应性差的问题,根据车辆动力传动系统结构,基于GT-SUITE软件建立废气涡轮增压柴油发动机以及控制系统的仿真模型,并基于台架试验对仿真模型进行了校核,保证动力传动系统模型具有较高的仿真精度。通过仿真探究冒烟极限限制、液力变矩器耦合工作点对起步加速性能的影响规律,明确发动机和液力变矩器耦合特性对提升车辆起步性能的作用机理,以提升车辆0~32 km/h加速性能为目标,制定车辆起步协调控制策略,并基于搭建的动力传动系统仿真模型对提出的协调控制策略进行仿真验证。研究结果表明:采用提出的协调控制策略车辆从0 km/h加速到32 km/h的弹射起步时间为9.8 s,而常规起步车辆从0 km/h加速到32 km/h的时间为14 s,新提出的协调控制策略对提升重型车辆的起步加速性能具有显著的效果。

永磁伺服系统转速跟踪控制与数据驱动的参数设计方法

在永磁伺服控制系统中,传统的转速控制策略在低频段存在幅值与相位偏差问题,降低了转速跟踪控制精度。为解决该问题,该文提出了一种高精度的转速跟踪控制策略与数据驱动的参数设计方法。主要思路是在转速控制环节串联一个滞后-超前补偿器,用以校正低频段的幅值与相位;以低频段补偿后的幅值及相位误差最小为优化目标,同时约束补偿器在全频带范围内的最大幅值增益和相移,设计了一种数据驱动的补偿器参数优化方法,并对补偿后控制系统的性能进行了分析评估。实验结果表明,基于实验数据所设计的补偿器在转速指令频率小于1 rad/s的低频段区间内,转速跟踪误差小于2 r/min,相较于传统方法控制精度显著提升;在跟踪转速阶跃指令时,该文方法和传统方法的控制效果相当,这说明该文方法在改善低频段跟踪性能的同时,保持了控制系统在中高频段原有的幅频和相频特性。

考虑响应滞后的矿用乳化液泵站泵头压力稳定模糊控制方法

为解决矿用乳化液泵站泵头压力无法及时准确地响应控制信号的变化、供液系统的非线性及时变性等问题,提出考虑响应滞后的矿用乳化液泵站泵头压力稳定模糊控制方法,通过构建基于Smith预估器的模糊控制系统,消除响应滞后对泵头压力的影响,生成无响应滞后的泵头压力预测值,并实时调整PID参数,减小泵头压力波动和误差,以实现对泵头压力的精确控制。试验结果表明,该方法能够解决响应滞后、非线性和时变性关系及抗干扰能力等问题,从而提高乳化液泵站控制系统的性能,确保泵头压力的稳定性和控制精度。

布尔网络同步方法综述

布尔网络同步作为研究热点近期取得了一些成果,包括布尔网络同步的基本概念、条件,同步控制的方法以及同步在实际系统中的应用。矩阵半张量积理论为布尔网络同步的研究提供了新的理论框架和方法,促进了该领域的发展和进步。通过该理论建立布尔网络同步模型,深入探讨节点之间的连接关系和状态更新规则,分析实现同步的充分必要条件,为丰富布尔网络同步研究提供了参考。