Robust adaptive leaderless consensus of unknown non-minimum phase linear multi-agent systems subject to disturbances and/or unmodeled dynamics

This article investigates the problem of robust adaptive leaderless consensus for heterogeneous uncertain nonminimumphase linear multi-agent systems over directed communication graphs. Each agent is assumed tobe of unknown nominal dynamics and also subject to external disturbances and/or unmodeled dynamics. Anovel distributed robust adaptive control strategy is proposed. It is shown that the robust adaptive leaderlessconsensus problem is solved with the proposed control strategy under some sufficient conditions. Two examplesare provided to demonstrate the efficacy of the proposed control strategy.

Distributed Adaptive Output Consensus of Unknown Heterogeneous Non-Minimum Phase Multi-Agent Systems

This article addresses the leader-following output consensus problem of heterogeneous linear multi-agent systems with unknown agent parameters under directed graphs.The dynamics of followers are allowed to be non-minimum phase with unknown arbitrary individual relative degrees.This is contrary to many existing works on distributed adaptive control schemes where agent dynamics are required to be minimum phase and often of the same relative degree.A distributed adaptive pole placement control scheme is developed,which consists of a distributed observer and an adaptive pole placement control law.It is shown that under the proposed distributed adaptive control scheme,all signals in the closed-loop system are bounded and the outputs of all the followers track the output of the leader asymptotically.The effectiveness of the proposed scheme is demonstrated by one practical example and one numerical example.

Output-feedback Dynamic Surface Control for a Class of Nonlinear Non-minimum Phase Systems

In this paper, an output-feedback tracking controller is proposed for a class of nonlinear non-minimum phase systems.To keep the unstable internal dynamics bounded, the method of output redefinition is applied to let the stability of the internal dynamics depend on that of redefined output, thus we only need to consider the new external dynamics rather than internal dynamics in the process of designing control law. To overcome the explosion of complexity problem in traditional backstepping design, the dynamic surface control(DSC) method is firstly used to deal with the problem of tracking control for the nonlinear non-minimum phase systems. The proposed outputfeedback DSC controller not only forces the system output to asymptotically track the desired trajectory, but also drives the unstable internal dynamics to follow its corresponding bounded and causal ideal internal dynamics, which is solved via stable system center method. Simulation results illustrate the validity of the proposed output-feedback DSC controller.

AN IMPROVEMENT OF THE RECURSIVE CLOSED-FORM ALGORITHM FOR NON-MINIMUM PHASE FIR SYSTEM IDENTIFICATION

An improved algorithm which is based on the recursive closed-form algorithm fornon-minimum phase FIR system identification via higher order statistics is presented.In order toincrease the parametric estimation accuracy,the improved algorithm uses the optimal iterativemethod to seek the nonlinear least-square solution.Finally,the simulation examples are alsogiven.

Adaptive fault-tolerant control for non-minimum phase hypersonic vehicles based on adaptive dynamic programming

In this paper,a novel adaptive Fault-Tolerant Control(FTC)strategy is proposed for non-minimum phase Hypersonic Vehicles(HSVs)that are affected by actuator faults and parameter uncertainties.The strategy is based on the output redefinition method and Adaptive Dynamic Programming(ADP).The intelligent FTC scheme consists of two main parts:a basic fault-tolerant and stable controller and an ADP-based supplementary controller.In the basic FTC part,an output redefinition approach is designed to make zero-dynamics stable with respect to the new output.Then,Ideal Internal Dynamic(IID)is obtained using an optimal bounded inversion approach,and a tracking controller is designed for the new output to realize output tracking of the nonminimum phase HSV system.For the ADP-based compensation control part,an ActionDependent Heuristic Dynamic Programming(ADHDP)adopting an actor-critic learning structure is utilized to further optimize the tracking performance of the HSV control system.Finally,simulation results are provided to verify the effectiveness and efficiency of the proposed FTC algorithm.

非最小相位工业过程自校正控制教学实验平台

工业过程中的非最小相位被控对象因其具有反向特性而会给控制器设计带来困难,在自动化教学中对非最小相位概念的描述通常偏重于零点位置、零动态等理论概念,因缺乏直观性而使得学生不易理解透彻。结合自适应控制课程教学,基于工业过程中典型的空气加热混合过程,通过合理构造实验条件,构建了具有非最小相位特性的物理被控对象装置,在此基础上,研发了自校正控制教学实验平台,可以开展非最小相位工业对象的辨识、控制和自校正控制的教学实验,有助于加深自动化专业学生对非最小相位概念的理解,从而改善教学效果。

非刚体运动特征提取在武术运动中的应用

受光照与环境因素的影响,非刚体运动中的图像会存在视差干扰,导致非刚体运动特征提取效果不佳,因此提出一种针对非刚体运动的特征提取方法。对非刚体运动图像进行高斯滤波处理,在高斯差分尺度空间内,采用特征描述算子提取初始特征点。根据特征点提取结果,计算非刚体运动特征提取的代价。引入引导滤波方法对非刚体运动图像进行视差效果优化处理,在最小视差约束下,根据置信度聚合与传播策略进行非刚体运动的特征精确提取。以武术运动作为实验对象,实验结果表明:所提方法的特征点提取精度较高,且视差提取误差率不超过2.0%。

非均匀网络中半径可调的ARDV-Hop定位算法

针对无线传感网络中传统DV-Hop(Distance Vector Hop)定位算法节点分布不均匀导致定位误差较大的问题,提出了非均匀网络中半径可调的ARDV-Hop(Adjustable Radius DV-Hop in Non-uniform Networks)定位算法。该算法通过半径可调的方式对节点间的跳数进行细化,用细化后呈小数级的跳数代替传统的整数级跳数,并建立了数据能量消耗模型,优化了网络传输性能。ARDV-Hop算法还针对节点分布不均匀的区域提出跳距优化算法:在节点密度大的区域,采用余弦定理优化跳距;密度小的区域,采用最小均方误差(Least Mean Square,LMS)来修正跳距。仿真实验表明,在同等网络环境下,与传统DV-Hop算法、GDV-Hop算法和WOA-DV-Hop算法相比,ARDV-Hop算法能更有效地降低定位误差.

基于组合基元法的非理想模型装配偏差预测算法研究

基于模型定义(model-based definition,MBD)体系的装配偏差算法适用于赛博空间中理想数模的装配场景,但不适用于物理空间中非理想状态的装配场景,导致现场产生大量修配工作。针对这一问题,文章模拟真实的装配场景,基于零件的非理想状态,并将配合特征之间的拓扑关系考虑在内,对装配偏差的传递与累积过程展开研究,给出一种装配偏差预测算法。首先,针对孔轴配合与槽轴配合,将装配约束转化为定位点约束,依据最大实体原则,构造柱面点云的最小包围圆,确定接触状态,给出串行装配偏差算法,并将以上两种配合定义为两种基元,对应的装配偏差算法定义为两种独立基元算法。其次,基于平面贴合、孔轴配合与槽轴配合给出并行装配偏差算法,并将其定义为组合基元算法。最后,基于非理想模拟数据进行实例验证,达到了准确预测装配偏差的目标,为后续在赛博空间基于实测数据的装配偏差计算提供理论依据,以促进高精度装配。

非最小相位高超声速飞行器非奇异滑模控制

针对受外界干扰和非最小相位影响下的高超声速飞行器的跟踪控制问题,提出基于Byrnes-Isidori(B-I)标准型的滑模控制策略。设计新的积分滑模面和新型复合趋近律,在趋近律中将指数函数和符号函数结合,提高高超声速飞行器的抗抖振能力和快速收敛性能。采用滑模控制方法构造鲁棒滑模控制器,保证内部动态的渐近稳定性。同时构造非奇异终端滑模控制器,保证速度跟踪误差的实际有限时间稳定性和外部动态的有界稳定性。结合非奇异终端滑模控制具有鲁棒性强、收敛速度快等特点,设计终端滑模干扰观测器解决速度子系统和航迹角子系统中的外界干扰问题,并利用Lyapunov理论进行稳定性分析,证明了估计误差的实际有限时间稳定性,对比仿真结果表明了基于B-I标准型的滑模控制策略的可行性和有效性。

On ADRC for non-minimum phase systems： canonical form selection and stability conditions

Active disturbance rejection control （ADRC）, as proposed by Prof. Jingqing Han, reduces first the plant dynamics to its canonical form, normally in the form of cascade integrators, for which the standard controller can be employed to meet the design specifications. This paper concerns with the selection of the canonical form for non-minimum phase systems. In particular, it is shown that, by employing the well known controllable canonical form, the uncertainties of such systems can be divided into two terms in the state space model, one in the control channel and the other in the output channel. The necessary and sufficient condition is obtained for the stability of the closed-loop system with the proposed canonical form and ADRC. Also, by showing the necessity of the detectability of the extended system as well as certain information of the system-s ＂zeros＂, we present the fundamental guidelines of design ADRC for non-minimum phase uncertain systems.

非最小相位法向电磁应力驱动快速刀具伺服系统轨迹跟踪控制

基于快速刀具伺服(FTS)的金刚石车削是复杂光学表面超精密制造的一种高效手段。为进一步提高具有非最小相位特征的电磁法应力驱动FTS的控制性能,将系统逆动力学补偿嵌入主控制回路中以改善被控对象动力学特征。对改善后的被控系统以比例微分积分(PID)和前馈补偿作为主控制器,并以基于内模原理的并联谐振控制器实现周期性轨迹的超高精度跟踪。考虑系统非最小相位特征,结合因子分解和镜像极点配置方法获得了系统稳定逆动力学模型。实验测试结果表明:该文所设计的控制方法,获得了1070 Hz(-3 dB)闭环带宽;100 Hz正弦轨迹实际跟踪误差小于±0.375%,并可对5 nm台阶轨迹进行稳定闭环跟踪,证明所设计的FTS控制系统可有效实现nm精度切削。

网络平台不作为的刑事归责:理据、路径及限度

网络平台能够精确匹配供需,迅速提高社会资源的配置效率,对我国社会经济的发展作出了重要贡献。但一系列案件显示,网络平台不作为与重大法益侵害之间具有因果关系。不能以“中立帮助行为论”否定网络平台不作为的刑事不法性。具有作为义务是平台成立不作为犯的前提条件,作为义务在实质上来源于行为人对“结果发生原因的支配”。网络平台作为义务的内容在相关法律法规中已有明确体现,但形式上的义务必须接受实质义务论的检验。对于网络平台的故意不作为,存在正犯与共犯两种归责路径,正犯归责的法律门槛较高,在绝大多数情况下都应从共犯角度考察其刑事责任。帮助信息网络犯罪活动罪并非立法上对帮助行为的正犯化,按照该罪对网络平台不作为进行定性仍然是对共犯归责路径的延续。具有间接帮助性质的平台不作为也应被纳入刑法的打击范围。网络平台的过失不作为不可能成立刑事犯罪。

Robust Stabilization of Non-minimum Phase Switched Nonlinear Systems with Uncertainty

This paper investigates the problem of robust stabilization of a class of switched nonlinear system with uncertain dynamics where each subsystem represents a non-minimum phase.The authors first construct a stabilizing sliding mode controller for each subsystem to stabilize individually its own unstable internal dynamics.Then,a switching strategy is introduced to select the most appropriate diffeomorphism through an infinity of diffeomorphisms.Sufficient conditions are specifically given for the exponential stability and the exponential upper bound of the trajectory of the switched subsystem,which guarantees the global asymptotical stability of the resulting switched system.Obviously,the proposed control approach can improvemore the transient state,compared to a feedback linearization based on only one diffeomorphism.Simulation studies illustrate the effectiveness of the suggested approach.

基于计算机视觉的输电塔位移监测ROI关键点法

为了实现输电塔远距离位移监测,同时满足低成本、无接触、易实施及精确度高等要求,结合输电塔的内轮廓特征和计算机视觉位移识别技术,提出感兴趣区域(region of interest,简称ROI)关键点法。首先,利用N近邻最小能量法进行ROI轮廓搜索提取,并与Harris角点检测算法相结合;其次,通过输电塔台架实验与灰度模板匹配法相比,ROI关键点法位移识别结果的平均误差、均方根误差分别降低了56%和45%,绝对误差小于5 mm和10 mm的准确率提高了61%和3%,计算效率提高了11倍,稳定性及抗噪性能较高;最后,在实验塔对比验证中,ROI关键点法的位移测量值与实际位移的差值百分比在0.0%~11.1%之间。结果表明,ROI关键点法在输电塔结构位移监测中具有较高的准确率、精细度、计算效率、稳定性及鲁棒性。

Multiple Models Direct Adaptive Controller for a Stochastic Non-minimum Phase System

For a stochastic non-minimum phase multivariable system,a multiple models direct adaptive controller is presented.It is composed of multiple fixed models with two adaptive models.The fixed models are used to cover the region where the system parameters jump and improve the transient response,while another two adaptive models are used to guarantee the stability.Utilizing generalized minimum variance design method,it adopts the stochastic system estimation algorithm with optimal controller design method to identify the controller parameter directly.Finally,the global convergence is given.The simulation proves the effectives of the controller proposed.

面向地铁施工环境的残差加权定位算法

在地铁施工环境中,进行地下室内定位,非视距误差是影响位置估计稳定性与准确性的一个重要因素。目前已经出现一些技术可以消除一定的非视距误差,但往往都需要关于非视距信道条件的先验信息。提出一种改进的残差加权位置估计算法(Developed residual weighting algorithm,D-rwgh),该算法基于最小残差原则,通过前一轮的计算不断剔除产生误差最大的基站,然后将不同基站数对应的位置估计进行残差加权,加权结果即为最终的定位结果。实验结果表明,该算法无需信道的先验信息,且在非视距传播环境下具有较好的定位精度。

A benchmark system to investigate the non-minimum phase behaviour of multi-input multi-output systems

In this paper,the problem of designing a multi-input multi-output(MIMO)systemfor studying the non-minimum phase(NMP)behaviour is considered.For this purpose,a NMP MIMO circuit is proposed and studied under different conditions.The main reason for designing this circuit is the lack of a simple and flexible benchmark for examining different control methods.Due to the simple structure and capability of showing different NMP characteristics,our proposed system is a suitable choice to study the behaviour of these systems.Also,our proposed system can be extended by series and parallel connections to generate more complicated benchmarks.The other advantages of this system are the large number of tunable parameters,adjustable interaction,variable number of poles and zeros,and inexpensive cost.Moreover,this benchmark can be used as a tool for hardware simulation.Finally,an optimal H∞decoupling control is applied to this benchmark to verify its effectiveness.

基于非值乘时间成本的乘务排班计划优化编制方法研究

乘务排班计划是城市轨道交通运输计划的重要组成部分,其编制方案优劣直接影响企业运营安全与乘务支出。在班制规定工作时间内,非值乘时间占比越高,工作所需人力资源越多,运营支出效益越低。文章通过缩减乘务人员非值乘时间中的非必要整备时间,从时间成本角度出发,构建最小费用模型。同时设计以爬山算法作为局部搜索策略的文化基因算法,用于优化传统遗传算法对于解的早熟或不收敛导致局部最优的潜在可能。最后以上海市轨道交通某条线路作为案例研究,结果表明模型能够在满足运营需求的前提下,优化乘务人员数量,从而降低乘务支出。其研究结果可为城市轨道交通精细化管理提供理论依据和参考。

基于贺兰山青海云杉(Picea crassifolia)树轮对过去202a最低气温的重建

在全球变暖的影响下,全球水文气候发生深刻变化,而季风与非季风过渡带地区气候复杂多样,所以摸清该地区过去长期气候变化规律是亟待解决的问题。利用36棵青海云杉(Picea crassifolia)的66个树轮样芯建立了季风与非季风过渡带典型地区(中国贺兰山地区)1798—2016年(219 a)的青海云杉树轮宽度年表,并且通过皮尔逊相关法分析了树轮宽度年表与该地气候因子的相关性。结果表明:(1)青海云杉径向生长与该地的年平均最低温(R2=0.638,P<0.001)关系密切,利用线性回归方程重建贺兰山1815—2016年年平均最低温序列,重建方程的缩减误差和有效系数分别为0.808、0.482。(2)重建的年平均最低温序列在19世纪整体气温偏低,与学术界公认的“小冰期”一致,到19世纪后期,气温逐渐回升,并且气温序列出现了显著的暖期和极暖年,气温在19世纪50和90年代以及20世纪90年代发生3次气温突变。(3)Morlet小波分析显示了6 a、21 a和46~56 a的周期性分布特征。南方涛动、太平洋十年涛动和大西洋多年代际涛动是这种周期性变化的驱动因素。(4)大尺度空间相关分析表明重建的气温序列对大尺度区域的气温变化具有较好的空间表征,如内蒙古大部和宁夏大部。进而重建的季风与非季风过渡带典型地区年平均最低气温序列揭示了该地的气候变化特征,为全球气候变化研究提供参考。