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.

Cooperative Target Tracking of Multiple Autonomous Surface Vehicles Under Switching Interaction Topologies

This paper is concerned with the cooperative target tracking of multiple autonomous surface vehicles(ASVs)under switching interaction topologies.For the target to be tracked,only its position can be measured/received by some of the ASVs,and its velocity is unavailable to all the ASVs.A distributed extended state observer taking into consideration switching topologies is designed to integrally estimate unknown target dynamics and neighboring ASVs'dynamics.Accordingly,a novel kinematic controller is designed,which takes full advantage of known information and avoids the approximation of some virtual control vectors.Moreover,a disturbance observer is presented to estimate unknown time-varying environmental disturbance.Furthermore,a distributed dynamic controller is designed to regulate the involved ASVs to cooperatively track the target.It enables each ASV to adjust its forces and moments according to the received information from its neighbors.The effectiveness of the derived results is demonstrated through cooperative target tracking performance analysis for a tracking system composed of five interacting ASVs.

Real-time State Monitoring During Switching Mode Transitions in High Power Three-level Inverters

大功率多电平逆变器近年来在实际工业生产中得到越来越广泛的应用。多电平逆变器由于结构复杂,采用元器件较多,因此在设计和实验中,实现各个工作状态下运行参数的同步监测和分析较为困难。本文针对大功率三电平逆变器,实现开关动态特性的在线测试,在此基础上,进一步研究三电平逆变器在开关状态变化时理论与实际负载运行工况下电路拓扑的转换变化规律。通过全电路电气参数和元器件状态的实时监测,发现在三电平逆变器非正常运行状态下开关转换时额外电应力,同时,深入研究在实际工况运行条件非正常状态下该额外电应力出现的机理和原因,为三电平逆变器的故障诊断提供了参考,对于设计高可靠性的多电平逆变器系统有一定的理论和现实意义。

Finite-Time H∞ Control of Switched Nonlinear Systems under State-Dependent Switching

This paper investigates the finite-time H∞ control problem of switched nonlinear systems via state-dependent switching and state feedback control. Unlike the existing approach based on time-dependent switching strategy, in which the switching instants must be given in advance, the state-dependent switching strategy is used to design switching signals. Based on multiple Lyapunov-like functions method, several criteria for switched nonlinear systems to be finite-time H∞ control are derived. Finally, a numerical example with simulation results is provided to show the validity of the conclusions.

On the Performance of Wireless-Powered Cooperative DF Relaying Networks with Imperfect CSI

This paper studies several performance metrics of a wireless-powered decode-and-forward(DF) relay network with imperfect channel state information(CSI). In particular, based on the time switching(TS) protocol, the energy-constrained relay harvesting energy from a power beacon(PB), and uses that harvested energy to forward the source information to destination. The closedform expression of the outage probability is firstly derived over Rayleigh fading channels. Then, the asymptotic analysis, throughput as well as the symbol error probability(SEP) are derived based on the expression of the outage probability. Next, both transmission power of the source and the power beacon are optimized through the throughput optimization. Finally, simulations are conducted to corroborate our theoretical analysis, and to reveal the impact of the transmission power of the source and PB as well as the imperfect CSI on the system performance.

Robust H_∞ output feedback controller design for linear uncertain discrete-time switched systems via state reset

This paper studies the problem of robust H∞ output feedback controller via state-reset for linear uncertain discrete-time switched systems. Using multiple Lyapunov functions,we address an output feedback controller under arbitrary switching signals,in which an H∞ performance is required. The condition is shown in the form of linear matrix inequalities (LMI). Finally,a numerical example shows the feasibility of the designed controller and illustrates that the new sufficient condition has lower conservation and more optimized H∞ tfperformance.

基于切换系统的城轨列车ATO控制策略研究

为弥补模糊PID控制在ATO(列车自动运行)系统中无法自动靠站等问题,将切换控制系统理念引入ATO中。针对A型地铁的受力情况,建立其运动学模型,并设计简单的运行路线。使用MATLAB对列车的运行过程进行仿真,在得出的运行特性图的基础上,建立列车的切换系统各工况的子空间模型及切换控制策略。为验证上述切换策略的有效性,对列车在终点路段的切换过程进行仿真得出列车能够稳定停车靠站的结论。最后,加入外界扰动的情况下,对列车危险路段的切换过程进行仿真,验证上述切换策略的有限时间稳定性。

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.

基于有限时间扩张状态观测器的水下机器人精准跟踪控制系统设计

水下机器人在运动过程中极易受到水环境因素的干扰发生运动偏移,为了保证水下机器人的精准、稳定航行,利用有限时间扩张状态观测器优化设计水下机器人精准跟踪控制系统;设计有限时间扩张状态观测器、水下机器人传感器、跟踪控制器和推进器,强化硬件系统的密封防水设计强度,完成系统硬件设计;根据水下航行任务,规划机器人的航行轨迹,作为系统控制目标;求解机器人位置、姿态角、速度等运动参数,得出水下机器人的跟踪结果;利用有限时间扩张状态观测器检测航行环境参数,结合当前机器人状态的跟踪结果,计算机器人运动控制量,在硬件系统的支持下,完成系统的精准跟踪控制功能;通过系统测试实验得出结论,静力水环境场景下水下机器人的平均位置跟踪误差为14 m、平均角度控制误差为0.10°,航行速度控制误差为0.5 m/s;动力水环境场景下水下机器人的位置跟踪误差最大值为9 m、平均角度控制误差为0.10°、航行速度控制误差为0.5 m/s。

分区互联配电网异步孤岛模式切换策略研究

大规模分布式电源的存在允许配电网通过网络重构改变供电方式,实现部分区域在必要时刻以异步孤岛形式运行。但配电网运行方式的改变必然伴随着关键换流器控制模式的切换和参数的调整,如何平稳地实现配电分区在并网和孤岛之间的转换是实现有源配电网安全可靠运行的重要内容。针对通过软开关(soft open point,SOP)实现柔性互联的配电分区,分析了该系统由并网转为异步孤岛运行的暂态特性,提出了基于参考功率自适应的改进下垂控制策略,并采用状态跟踪方法降低了配电网运行状态切换时刻的暂态波动,实现了配电网运行方式的平滑切换。在PSCAD/EMTDC环境下搭建了仿真模型进行验证,结果表明,所提控制方法可有效提升分区互联有源配电网运行的灵活性。

基于有限时间状态观测器的永磁同步直线电机递归终端滑模控制

针对载荷变化、非线性摩擦、推力波动和外部扰动等不确定性降低永磁同步直线电机位置跟踪性能的问题,提出一种基于有限时间状态观测器的递归终端滑模控制方法。首先,建立考虑有界集总不确定性的直线电机动力学模型。其次,设计快速终端滑模函数和积分滑模函数的递归结构,强制系统直接从滑模面启动,减少了跟踪误差的收敛时间。然后,引入有限时间状态观测器实时估计集总不确定性并前馈补偿到控制率中,提高系统的鲁棒性和减少抖振。接着,利用李雅普诺夫理论分析闭环控制器的稳定性和有限时间收敛性。最后,搭建基于半实物AD5435的实验平台,实验结果验证了所提方法的可行性和优越性。

融合时空信息的Transformer单目标跟踪算法

目前,主流的基于孪生网络的单目标跟踪方法,通过计算模板与搜索区域之间的相似度来匹配目标,缺乏对目标时空状态信息的利用。特别是当场景中存在多个相似目标时,孪生网络跟踪器往往无法精确区分目标,从而导致跟踪错误。针对上述问题,提出一种融合时空信息的Transformer单目标跟踪算法(SIFTransT)。该算法通过MixFormer(end-to-end tracking with iterative mixed attention)跟踪器获取初步的跟踪结果,设计了一个目标状态计算模块,用于计算并存储目标的状态信息,包括目标位置、边界框、速度、加速度、运动方向等,以此深入挖掘目标状态信息。构建了一个基于Transformer的时空信息融合模块,利用编码器的自注意力和解码器的交叉注意力,深入融合目标最近一段时间的状态信息,从而更加准确地对目标状态进行建模,提高目标跟踪的准确性。在LaSOT数据集上的实验结果表明,相比基准算法MixFormer,SIFTransT算法在AUC指标提高了2.8个百分点,PNorm指标提升了2.6个百分点,P指标提升了2.1个百分点,在搭载RTX8000显卡的服务器上平均每秒处理帧数达28帧。

基于脉冲变压器的快前沿固态触发器

结合理论求解、仿真分析与实验验证,确定了影响脉冲变压器型触发器输出前沿的主要因素,并研制了一台能可靠触发真空沿面闪络开关导通的快前沿固态触发器。研究结果表明:影响触发器输出脉冲前沿的关键因素为脉冲变压器漏感、匝数比和半导体开关开通速度;不同绕制方式的脉冲变压器漏感差异很大,最小漏感绕法的变压器漏感值低1个数量级;选用开通速度优于15 ns的碳化硅金属氧化物半导体场效应晶体管(SiC MOSFET)、绕制低漏感(小于0.5μH)的脉冲变压器,实现了前沿为20.4 ns(10%~90%)、幅值为16.5 kV的快前沿输出;控制SiC MOSFET的驱动脉宽在35~55 ns变化可以控制触发电流峰值在35~55 A范围内变化。

Input-to-state stability of switched nonlinear systems

The input-to-state stability （ISS） problem is studied for switched systems with infinite subsystems. By using multiple Lyapunov function method, a sufficient ISS condition is given based on a quantitative relation of the control and the values of the Lyapunov functions of the subsystems before and after the switching instants. In terms of the average dwell-time of the switching laws, some sufficient ISS conditions are obtained for switched nonlinear systems and switched linear systems, respectively.

基于时序控制的固态开关串并联高压脉冲技术

针对生物医疗等高压陡脉冲应用需求,设计了基于固态开关串并联高压陡脉冲发生电路,并结合时序控制技术,提出一种脉冲陡化新方法;从理论上分析了脉冲陡化的关键、系统工作的过程以及设计要点。该方法能较好解决开关管增加后杂散参数、布线电感以及导线电感对开关速度的影响。以2 kV高压直流电源、110Ω的负载电阻进行实验,负载脉冲信号的上升沿约为50 ns,下降沿约为70 ns,输出电流幅值约18 A;最小脉宽信号的半高宽为100 ns,系统的最小分辨率为5 ns,可实现步进为5 ns脉宽的灵活调节,最大脉宽则与储能电容有关。

Output Feedback Tracking Control for a Class of Switched Nonlinear Systems with Time-varying Delay

This paper studies the problem of tracking control for a class of switched nonlinear systems with time-varying delay. Based on the average dwell-time and piecewise Lyapunov functional methods, a new exponential stability criterion is obtained for the switched nonlinear systems. The designed output feedback H∞controller can be obtained by solving a set of linear matrix inequalities(LMIs).Moreover, the proposed method does not need that a common Lyapunov function exists for the switched systems, and the switching signal just depends on time. A simulation example is provided to demonstrate the effectiveness of the proposed design scheme.

具有时变全状态约束的多输入多输出非线性切换系统指定性能事件触发控制

针对多输入多输出切换非线性系统面临的不可测状态、状态约束、通信资源受限等挑战,本文研究了一种具有指定性能的事件触发控制策略。借助状态观测器和模糊逻辑系统,完成对不确定系统的建模。将命令滤波引入至反步递推(Backstepping)设计过程,以避免因虚拟控制器反复求导引起的计算爆炸问题,并通过设计指定性能函数,保证系统的瞬态性能。通过构造事件触发控制器和障碍李雅普诺夫函数,有效解决时变状态约束及通讯资源受限的问题,并保证系统的稳定性。最后通过仿真验证控制算法的有效性。

基于移动闭塞的状态发车技术研究

在移动闭塞基础上,根据列车运行计划、列车状态、列车位置、列车制动性能、站场区段状态以及道岔位置等条件,以区段及道岔建立二叉树模型,搜索列车走行路径,判断列车位置出清关键道岔区段节点,计算后续发车进路办理时机,办理后续发车进路,实现进路由计划办理到状态办理转变,发车由计划发车到状态发车转变。缩短发车时间间隔,进而提升车站发车能力。

一类切换时滞神经网络的有限时间无源性

为了研究切换拓扑下的时滞神经网络有限时间无源性,通过设计状态依赖型切换信号和控制器的方法,得到在切换拓扑下的时滞神经网络具有有限时间无源性的结论,进而得到有限时间镇定的结论。当2个时滞神经网络系统都具有有限时间无源性时,通过设计切换信号的方法,得到它们的反馈互联系统具有有限时间无源性的结论,通过数值例子验证定理结果的有效性。