Dynamic train dwell time forecasting:a hybrid approach to address the influence of passenger flow fluctuations

Train timetables and operations are defined by the train running time in sections,dwell time at stations,and headways between trains.Accurate estimation of these factors is essential to decision-making for train delay reduction,train dispatching,and station capacity estimation.In the present study,we aim to propose a train dwell time model based on an averaging mechanism and dynamic updating to address the challenges in the train dwell time prediction problem(e.g.,dynamics over time,heavy-tailed distribution of data,and spatiotemporal relationships of factors)for real-time train dispatching.The averaging mechanism in the present study is based on multiple state-of-the-art base predictors,enabling the proposed model to integrate the advantages of the base predictors in addressing the challenges in terms of data attributes and data distributions.Then,considering the influence of passenger flow on train dwell time,we use a dynamic updating method based on exponential smoothing to improve the performance of the proposed method by considering the real-time passenger amount fluctuations(e.g.,passenger soars in peak hours or passenger plunges during regular periods).We conduct experiments with the train operation data and passenger flow data from the Chinese high-speed railway line.The results show that due to the advantages over the base predictors,the averaging mechanism can more accurately predict the dwell time at stations than its counterparts for different prediction horizons regarding predictive errors and variances.Further,the experimental results show that dynamic smoothing can significantly improve the accuracy of the proposed model during passenger amount changes,i.e.,15.4%and 15.5%corresponding to the mean absolute error and root mean square error,respectively.Based on the proposed predictor,a feature importance analysis shows that the planned dwell time and arrival delay are the two most important factors to dwell time.However,planned time has positive influences,whereas arrival delay has negative influences.

时变通信拓扑下车辆队列的自适应事件触发混合H_(∞)与无源性控制

本文研究了时变通信拓扑影响下,车辆自组织网络(VANET)上自动车辆的自适应事件触发队列控制问题.为了描述车对车(V2V)通信拓扑的时变特性,本文采用“基于平均驻留时间”的切换信号对其建模.为了降低通信负担,本文采用了一种新的自适应事件触发机制.与传统触发机制不同,该触发机制的阈值参数并非常数,而是能根据车辆的状态变化进行实时的动态调节,据此建立车辆队列误差模型.为降低外界扰动的影响,引入混合H_(∞)与无源性能指标,使控制系统对干扰具有较强的鲁棒性.通过构建模态依赖的李雅普诺夫函数,得到控制算法,并通过一个数值仿真验证了本文提出理论算法的有效性.

基于MDADT方法的离散切换系统L_2增益分析

主要研究一类离散时间的线性切换系统的稳定性和L_2增益问题,将应用一种模式依赖平均驻留时间(MDADT)的方法来分析这类离散时间线性切换系统的L_2增益属性。模式依赖平均驻留时间是指在系统每个切换模式下都有自己的平均驻留时间,这使得驻留时间与系统的模式相关。因此,旨在找到一个准确的可容许的切换信号下的MDADT值,使得整个系统是稳定的。利用多Lyapunov函数方法得到系统稳定及L_2增益属性的充分条件,该条件是典型的线性矩阵不等式,可用LMIs直接来求解。MDADT方法的引入,使得驻留时间小于一般情况下的平均驻留时间,从而使得系统全局一致指数稳定的条件具有更少的保守性。

切换正时滞系统的异步镇定性

本文讨论了带有时滞的离散时间切换正系统的异步镇定性问题。首先,设计一类异步状态反馈控制器,通过构造一类多余正Lyapunov-Krasovskii泛函,利用前向平均驻留时间(FADT)切换信号的概念,得到闭环系统是指数稳定的一个充分条件;其次,基于该定理给出控制器增益的具体形式;最后,给出一个数值例子验证所得结果的有效性。

基于容许边界依赖ADT方法的DC/DC变换器控制

电力电子电路具有连续时间变量与离散事件互相混杂、互相作用的特点,是一类典型的混杂系统。基于混杂系统理论,利用多李雅普诺夫函数稳定性方法结合容许边界依赖平均驻留时间约束条件,设计了一种可使DC/DC变换器达到期望输出的切换规则,其稳定性控制条件通过解线性矩阵不等式(LMI)得到。在此基础上,加入了比例积分控制器保证DC/DC变换器在负载扰动下的稳定性。此控制方法能保证系统稳定,同时可有效抑制系统的抖振并降低开关频率。最后,通过仿真得出了Buck、Boost、Buck/Boost电路的仿真曲线,并搭建Buck电路实验样机进行了验证,结果证明了所提方法的有效性。

Robust exponential stability of uncertain discretetime impulsive switching systems with state delay

A new class of hybrid impulsive and switching models are introduced and their robust exponential stability and control synthesis are addressed. The proposed switched system is composed of stable subsystems and unstable subsystems, which not only involves state delay and norm-bounded time-varying parameter uncertainties, but also contains the impulsive switching effects between the subsystems. Based on the extension of the system dimension and the concept of average dwell time, a kind of practically useful switching rule is presented which guarantees the desired robust exponential stability. A switched state feedback controller is also given.

Robust Exponential Stability of Discrete Time Perturbed Impulsive Switched Systems

The robust exponential stability of a class of discrete time impulsive switched systems with structure perturbations is studied. Based on the average dwell time concept and by dividing the total activation time into the time with stable subsystems and the time with unstable subsystems, it is shown that if the average dwell time and the activation time ratio are properly large, the given switched system is robustly exponentially stable with a desired stability degree. Compared with the traditional Lyapunov methods, our layout is more clear and easy to carry out. Simulation results validate the correctness and effectiveness of the proposed algorithm.

H_-/H_∞ fault detection filter design for interval time-varying delays switched systems

The problem of the robust fault detection filter design for time-varying delays switched systems is considered in the framework of mixed H-/H∞. Firstly, the weighted H∞ performance index is utilized as the robustness performance, and the H- index is used as the sensitivity performance for obtaining the robust fault detection filter. Then a novel multiple Lyapunov-Krasovskii function is proposed for deriving sufficient existence conditions of the robust fault detection filter based on the average dwell time technique. By introducing slack matrix variable, the coupling between the Lyapunov matrix and system matrix is removed, and the conservatism of results is reduced. Based on the robust fault detection filter, residual is generated and evaluated for detecting faults. In addition, the results of this paper are dependent on time delays,and represented in the form of linear matrix inequalities. Finally,the simulation example verifies the effectiveness of the proposed method.

Event-Triggered Finite-Time <i>H</i>_∞Control for Switched Stochastic Systems

This paper investigates the problem of event-triggered finite-time H∞ control for a class of switched stochastic systems. The main objective of this study is to design an event-triggered state feedback H∞ controller such that the resulting closed-loop system is finite-time bounded and satisfies a prescribed H∞ level in some given finite-time interval. Based on stochastic differential equations theory and average dwell time approach, sufficient conditions are derived to ensure the finite-time stochastic stability with the prescribed H∞ performance for the relevant closed-loop system by employing the linear matrix inequality technique. Finally, the desired state feedback H∞ controller gain matrices can be expressed in an explicit form.

变负载机械手轨迹跟踪控制器设计

本文针对具有变负载的不确定刚性机械手系统,提出了一种依赖平均驻留时间的神经网络自适应切换控制策略.本控制方案将夹持不同负载的刚性机械手系统视为切换系统,即根据负载的不同将整个系统分为若干子系统,并基于平均驻留时间原则对每个子系统分别设计控制器.在各子系统中,分别采用径向基函数(RBF)神经网络逼近系统结构参数,以避免控制器对系统精确模型的依赖.同时,基于神经网络设计鲁棒补偿项,以抑制集总扰动对系统的影响.然后,利用多Lyapunov函数方法证明了轨迹跟踪误差的一致最终有界性.最后,通过仿真验证,所提出的控制方案不仅可实现变负载机械手期望轨迹的高精度跟踪,而且可有效削弱输入力矩的抖振.

具有不确定性的倾转旋翼机过渡模态模糊控制设计

针对存在未知不确定性的倾转旋翼机从直升机模态到固定翼模态的模型切换稳定性问题,提出了基于模型依赖平均驻留时间方法的模糊自适应切换控制策略。首先,建立了倾转旋翼机的纵向运动系统模型。其次,针对倾转旋翼机过渡过程存在的未知不确定性,采用模糊逻辑系统对其不确定项进行逼近;针对存在不确定性的倾转旋翼机平稳切换问题,提出了模糊自适应鲁棒飞行控制策略,并从理论分析层面严格证明了所提出控制器的有效性。最后,仿真结果表明所提出的控制方法能够有效地实现倾转旋翼机模态转换过程中的轨迹跟踪,提升了飞行器的操控性和稳定性。

Stability of Switched Positive Descriptor Systems with Average Dwell Time Switching

In this paper, the problems of stability for a class of switched positive descriptor systems(SPDSs)with average dwell time(ADT) switching are investigated. First, based on the equivalent switched system and the properties of the projector matrix, sufficient stabilities are given for the underlying systems in both continuoustime and discrete-time contexts. Then, a sufficient stability condition for the SPDS with both stable and unstable subsystems is obtained. The stability results for the SPDSs are represented in terms of a set of linear programmings(LPs) by the multiple linear co-positive Lyapunov function(MLCLF) approach. Finally, three numerical examples are given to illustrate the effectiveness of the obtained theoretical results.

Event-triggered finite-time guaranteed cost control of asynchronous switched systems under the round-robin protocol via an AED-ADT method

This paper focuses on addressing the problems of finite-time boundedness and guaranteed cost control in switched systems under asynchronous switching.To reduce redundant information transmission and alleviate data congestion of sensor nodes,two schemes are proposed:the event-triggered scheme(ETS)and the round-robin protocol(RRP).These schemes are designed to ensure that the system exhibits good dynamic characteristics while reducing communication resources.In the field of finite-time control,a switching signal is designed using the admissible edge-dependent average dwell time(AED-ADT)method.This method involves a slow AED-ADT switching and a fast AED-ADT switching,which are respectively suitable for finite-time stable and finite-time unstable situations of the controlled system within the asynchronous switching interval.By constructing a double-mode dependent Lyapunov function,the finite-time bounded criterion and the controller gain of the switched systems are obtained.Finally,the validity of the proposed results is showcased by implementing a buck-boost voltage circuit model.

Stabilization of switched linear systems under asynchronous switching subject to admissible edge-dependent average dwell time

The problem of stabilizing switched linear systems under asynchronous switching is addressed.The admissible edge-dependent average dwell time method is applied to design a switching signal that comprises slow admissible edge-dependent average dwell time and fast admissible edge-dependent average dwell time.Under this switching signal,the restriction that the maximum delay of asynchronous switching is known in advance is removed.The constructed Lyapunov function is associated with both the system mode and controller mode.The stabilization criteria and the corresponding algorithm are presented to obtain the controller gains and to design the switching signal.Finally,two examples are given to demonstrate the effectiveness of the proposed results.

随机非线性切换系统的周期事件驱动控制

针对随机非线性切换系统,为避免芝诺现象和减少通信资源的浪费,研究了基于采样数据的周期事件驱动控制问题。首先,利用融合切换信号技术,将闭环切换系统转换成具有状态延迟和融合切换信号的随机非线性切换系统;其次,在周期事件驱动方案下,通过构造合适的李雅普诺夫函数,在满足平均驻留时间的切换信号下,得到了闭环切换系统的均方指数稳定性的充分条件;再次,给出了状态反馈控制器和事件驱动参数的设计方法;最后,通过一个数值例子验证了所提出方法的有效性,该实验结果表明了在所设计的控制方法下,闭环切换系统的状态是均方指数稳定的,同时还能减少通信资源的消耗。

含执行器故障的切换非线性系统的事件触发自适应模糊容错控制

本文研究在平均驻留时间约束下,一类含有执行器故障的切换非线性系统输出反馈自适应模糊事件触发容错控制问题.首先,建立了一个模态依赖的状态观测器估计不可测量状态.利用模糊逻辑系统来逼近未知项.其次,构建自适应模糊容错事件触发控制方案能够节省网络资源和数据传输.然后,通过构造多Lyapunov函数和平均驻留时间法,证明闭环系统所有状态半全局一致最终有界的同时排除了Zeno现象.最后,通过数值仿真验证该方法的有效性.

Pose Synchronization of Multiple Rigid Bodies Under Average Dwell Time Condition

This paper considers the pose synchronization problem of a group of moving rigid bodies under switching topologies where the dwell time of each topology may has no nonzero lower bound. The authors introduce an average dwell time condition to characterize the length of time intervals in which the graphs are connected. By designing distributed control laws of angular velocity and linear velocity,the closed-loop dynamics of multiple rigid bodies with switching topologies can be converted into a hybrid dynamical system. The authors employ the Lyapunov stability theorem, and show that the pose synchronization can be reached under the average dwell time condition. Moreover, the authors investigate the pose synchronization problem of the leader-following model under a similar average dwell time condition. Simulation examples are given to illustrate the results.

Robust H_∞ static output feedback control of discrete-time switched polytopic linear systems with average dwell-time

This paper investigates the problem of robust exponential H∞ static output feedback controller design for a class of discrete-time switched linear systems with polytopic-type time-varying parametric uncertainties. The objective is to design a switched static output feedback controller guaranteeing the exponential stability of the resulting closed-loop system with a minimized exponential H∞ performance under average dwell-time switching scheme. Based on a parameter-dependent discontinuous switched Lyapunov function combined with Finsler＇s lemma and Dualization lemma, some novel conditions for exponential H∞ performance analysis are first proposed and in turn the static output feedback controller designs are developed. It is shown that the controller gains can be obtained by solving a set of linear matrix inequalities （LMIs）, which are numerically efficient with commercially available software. Finally, a simulation example is provided to illustrate the effectiveness of the proposed approaches.

切换正线性系统在模型依赖平均驻留时间下的异步L_(1)控制

研究一类切换正线性系统在模型依赖平均驻留时间(MDADT)切换信号下的异步L_(1)控制问题.通过构造适当的李亚普诺夫(Lyapunov)函数,基于MDADT切换信号,讨论了一类切换正线性系统在异步切换下的指数稳定性,并进一步给出了其在异步切换下具有指数的L_(1)-增益性能γ的充分条件.基于已建立的稳定性定理和MDADT切换信号,设计了一类异步状态反馈控制器,使得闭环系统在异步切换下是正的并且具有指数的L_(1)-增益性能γ,给出了求解控制器的增益矩阵K_(i)的具体算法.此外,所得结论都是以代数矩阵不等式的形式给出的,可以利用Matlab中的LP工具箱进行求解.给出了一个数值算例验证了所得结论的有效性和可行性.