红外光幕在地铁屏蔽门障碍物探测中的研究

针对现有地铁屏蔽门通过门速曲线的改变来探测障碍物的方法在检测最小尺寸为4 mm×40 mm的障碍物中所存在的不足,提出一种利用红外光幕的障碍物探测方法,并结合数字信号处理器(DSP)的无刷直流电动机控制技术和模糊PID控制算法来实现地铁屏蔽门障碍物的探测,最后在Matlab/Simulink环境中构建了整个系统的数学模型,并对系统在正常情况和遇到障碍物时的关门过程进行仿真分析。仿真结果表明:基于该方法设计的地铁屏蔽门障碍物探测系统可以解决现有地铁屏蔽门在障碍物探测方面的不足。     

磨矿粒度动态过程的一种快速Monte Carlo仿真方法

磨矿是降低矿物粒度的工业过程,产品粒度是磨矿过程的关键质量指标. 由于磨矿粒度难以在线检测且磨矿生产过程具有综合复杂特性,难以采用传统控制方法实现磨矿粒度的控制. 因此,建立磨矿粒度和关键工艺参数的动态模型对于磨矿运行控制和优化具有重要意义. 采用总量平衡原理获得磨矿粒度的微分方程模型多数情况下无法获得解析解. 而基于Monte Carlo （MC）方法的磨矿粒度模型能够精确模拟磨矿粒度分布的动态变化,但是其仿真效率低难以实用. 本文针对这一问题提出一种新的MC仿真方法: 在定总量方法的基础上引入新的颗粒移除机制,在移除过程中动态地分配各个粒级颗粒数目并保持破裂前后各个粒级颗粒所占总颗粒数的百分比不变,避免颗粒移除过程中由于粒级差异导致的抽样误差,且避免MC仿真速度随着仿真推进下降的问题. 仿真实验验证表明,本方法能够在保证一定精度前提下显著提高磨矿粒度MC仿真的计算速度. 最后,通过一个实例介绍了本文仿真模型在磨矿优化控制中的应用.     

非线性系统的模糊免疫PSD控制与仿真

针对模糊免疫PID控制算法中微分与积分增益不能根据系统特性自动调整的问题,提出了一种模糊免疫PSD(Proportional Summation Derivative)控制算法。该方法将自适应PSD算法与模糊免疫PID算法相结合,利用自适应PSD控制算法根据过程误差的几何特性建立的PSD控制规律,使得模糊免疫PID控制算法中的微分和积分增益可以随比例增益的变化而自适应调整,从而进一步提高控制算法的自适应性能。仿真实验表明,采用该算法可以提高非线性、时变系统的控制性能,并能减少参数调整的工作量。     

Control of particle size distribution described by a population balance model of semibatch emulsion polymerization

This work addresses the computation of surfactant feed profiles for shaping a particle size distribution to a bimodal target distribution. A fundamental population balance model of styrene semibatch emulsion polymerization is used in this control study. Both surfactant feed rate and free surfactant concentration are considered as alternative control variables and a comparison is made of the two approaches. A comparison is also made of several different objective function norms in the optimization. Results suggest that a min–max norm, tied to the distribution modes, is the most appropriate metric.     

An efficient method for stochastic optimal control with joint chance constraints for nonlinear systems

Stochastic model predictive control hinges on the online solution of a stochastic optimal control problem. This paper presents a computationally efficient solution method for stochastic optimal control for nonlinear systems subject to (time‐varying) stochastic disturbances and (time‐invariant) probabilistic model uncertainty in initial conditions and parameters. To this end, new methods are presented for joint propagation of time‐varying and time‐invariant probabilistic uncertainty and the nonconservative approximation of joint chance constraint (JCC) on the system state. The proposed uncertainty propagation method relies on generalized polynomial chaos and conditional probability rules to obtain tractable expressions for the state mean and covariance matrix. A moment‐based surrogate is presented for JCC approximation to circumvent construction of the full probability distribution of the state or the use of integer variables as required when using the sample average approximation. The proposed solution method for stochastic optimal control is illustrated on a nonlinear semibatch reactor case study in the presence of probabilistic model uncertainty and stochastic disturbances. It is shown that the proposed solution method is significantly superior to a standard random sampling method for stochastic optimal control in terms of computational requirements. Furthermore, the moment‐based surrogate for the JCC is shown to be substantially less conservative than the widely used distributionally robust Cantelli‐Chebyshev inequality for chance constraint approximation.     

Ad-hoc网络PSD拥塞控制算法

神经元PID算法能较好地控制队列长度,但其神经元增益对被控对象的状态较为敏感,基于试凑和经验的设定往往使控制效果难以保证。基于TCP拥塞窗口加法增大、乘法减小原则和排队机制,推导出拥塞窗口与丢弃概率、队列长度的微分方程,再对方程进行线性化,获得Ad-hoc网络TCP/AQM控制系统模型。基于该模型,将递推计算修正功能引入神经元PID,设计了一种神经元自适应PSD的AQM。该算法可以在线调整神经元增益。NS仿真表明,在无线分组丢失、突发流及链路容量变化的Ad-hoc网络中,PSD队列管理性能优于神经元PID。     

水下自主导航系统算法设计

基于微小型水下机器人的导航需求,结合水下机器人应用环境的特点,在既定的元器件与处理芯片基础上,提出了水下组合导航算法的设计原则,选取合适的状态量和量测量,建立状态方程与量测方程,建立一套集中式Kalman滤波导航系统算法。算法保证导航系统能够满足长航时下高精度需求,具有较高的抗干扰能力,同时充分利用现有的各项传感器输出信息,保证系统的稳定性。并用实验小车进行陆上实验,验证算法的正确性。     

Robust PID‐PSD Controller Design: BMI Approach

A new robust proportional‐integral‐derivative (PID)–proportional‐sum‐derivative (PSD) controller design method based on linear (bilinear) matrix inequalities (LMI, BMI) is proposed for uncertain affine linear system. The design procedure guarantees the parameter dependent quadratic stability, and guaranteed cost control with a new quadratic cost function (LQRS) including the derivative term for the state vector as a tool to influence the overshoot and response rate. The second approach to the PSD controller design procedure is based on a Lyapunov function with a special term corresponding to the time‐delay part of the control algorithm. The results obtained are illustrated on three examples to show the robust PID, PSD control design procedure and the influence of the choice of matrix S in the extended cost function.     

Observers for state-affine systems

A system whose discrete-time model is linear in state variables and nonlinear in control variables is considered. Under the assumption of generic observability (under single experiment) an exact observer algorithm is suggested. Also, it is shown that the existence of a general nonlinear asymptotic observer implies the existence of a linear one. Two design procedures for asymptotic observers are presented. Surprisingly, one of them extends to a rather complete solution for continuous-time systems with piecewise constant controls provided discrete output measurements are more frequent than switches of control values.     

State estimator for multisensor systems with irregular sampling and time-varying delays

This article addresses the state estimation in linear time-varying systems with several sensors with different availability, randomly sampled in time and whose measurements have a time-varying delay. The approach is based on a modification of the Kalman filter with the negative-time measurement update strategy, avoiding running back the full standard Kalman filter, the use of full augmented order models or the use of reorganisation techniques, leading to a lower implementation cost algorithm. The update equations are run every time a new measurement is available, independently of the time when it was taken. The approach is useful for networked control systems, systems with long delays and scarce measurements and for out-of-sequence measurements.     

基于FP_tree的频繁项目集增量式更新算法

对频繁项目集的更新问题进行研究,提出一种基于频繁模式树的频繁项目集增量式更新算法。充分利用已有挖掘结果,有效解决最小支持度和事务数据库同时发生变化时相应频繁项目集的更新问题。在事务数据库变化同时包括增加和减少的情况下,对算法性能进行分析与测试,结果证明该算法高效可行。     

网络控制系统Smith Fuzzy PID控制器的设计

针对网络控制系统中普遍存在的时延问题,提出了一种将模糊自适应算法和Smith预估补偿算法与常规PID控制器相结合的智能控制策略。该方法充分利用了Smith预估控制算法对带时延系统的良好控制能力,同时利用模糊推理算法实现对PID参数的在线自整定,进一步改善PID控制器的性能。仿真结果表明,基于该智能控制器的网络控制系统克服了传统PID控制超调量大及常规Smith预估补偿过分依赖于被控对象精确数学模型的缺陷,可以有效降低时延对系统性能的不利影响,使被控对象具有良好的动、静态特性。     

Online Noise Estimation Using Stochastic-Gain HMM for Speech Enhancement

We propose a noise estimation algorithm for single-channel noise suppression in dynamic noisy environments. A stochastic-gain hidden Markov model (SG-HMM) is used to model the statistics of nonstationary noise with time-varying energy. The noise model is adaptive and the model parameters are estimated online from noisy observations using a recursive estimation algorithm. The parameter estimation is derived for the maximum-likelihood criterion and the algorithm is based on the recursive expectation maximization (EM) framework. The proposed method facilitates continuous adaptation to changes of both noise spectral shapes and noise energy levels, e.g., due to movement of the noise source. Using the estimated noise model, we also develop an estimator of the noise power spectral density (PSD) based on recursive averaging of estimated noise sample spectra. We demonstrate that the proposed scheme achieves more accurate estimates of the noise model and noise PSD, and as part of a speech enhancement system facilitates a lower level of residual noise.     

基于ZigBee网络和自适应PSD算法的路灯分布式节能控制方法

当前照明系统缺乏分布式路灯动态化控制,浪费大量能源,为此,提出了基于ZigBee网络和自适应PSD算法的路灯分布式节能控制方法。通过ZigBee网络通信连接系统传感器、控制中心和照明终端,协调设备通信功能,实现信息快速传输储存。利用神经网络处理信号数据,提高系统信号检测和处理效率。在此基础上,利用自适应PSD算法识别路灯信号动态特征,进行自适应信号检测,调节信号数据偏差,精确检测数据结果,增强系统节能控制稳定程度,实现路灯分布式节能控制。由实验结果可知,研究方法将分布式路灯检测精准度提高到99%,熔池宽度稳定在3.5W/mm,具有良好的检测精准度和控制稳定性,可以对路灯进行节能控制。     

一种频繁项集的快速挖掘算法

关联规则的发现是数据挖掘的一个重要方面,产生频繁项集是其中一个关键步骤。提出了一种基于十字链表快速挖掘频繁项集的算法,该算法只需扫描一次数据库,充分利用已有信息产生频繁项集,无需存储候选项集。通过与其它一些算法比较,说明该算法有更好的性能。     

基于AR模型的置信规则库结构识别算法

针对以置信规则推理作为系统控制器的应用,传统的置信K均值聚类算法往往不能充分利用数据中时间上的动态关联信息。因此,在模糊聚类算法的基础上引入自回归(AR)模型,将集约生产计划中的需求数据作为一组时间序列进行动态的聚类分析。该算法不仅可以充分利用集约生产计划中的需求数据的内部自相关性,而且可以进一步利用隶属度函数对AR模型的预测过程进行模糊化调整,从而得到更为理想的置信规则库结构,提高推理与决策的精度。     

改进免疫粒子群算法在矿车调度优化中的应用

提出了一种基于自适应搜索的改进免疫粒子群算法.算法在传统免疫粒子群算法的基础上,对子种群进行分组,以并联形式对算法进行融合,动态调整各组子种群规模,根据粒子最大浓度值自适应调整搜索范围.首先,算法融合了浓度调节机制,结合粒子最大浓度值来调节子种群数目以充分利用粒子群资源;与此同时,针对次优子种群进行疫苗接种,利用粒子最大浓度值调节接种疫苗的搜索范围,在避免了种群退化现象的同时,提高了算法的收敛精度和全局搜索能力.文中建立了露天矿山矿车调度模型并进行了仿真实验,仿真结果表明,所提算法充分利用了矿车资源,具有一定优越性和较好的工程应用价值.     

An example of robust internal model control under variable and uncertain delay

This paper proposes a particular study of the classic internal model control algorithm for a sampled-data system in a generalized context of uncertainty. Besides the usually considered model mismatch, the particularity of the case under consideration is that the measurements available to the control algorithm suffer from large, varying and uncertain delays. The presented study considers a simple SISO nonlinear system. The control algorithm is a sampled nonlinear model-based controller with successive model inversion and bias correction. The main contribution of this article is its proof of global convergence and robustness despite time-varying delays and uncertain measurement dating. In particular, the model error, the varying delays and measurements dating error are treated using monotonicity of the system and a detailed analysis of the closed-loop behaviour of the sampled dynamics, in an appropriate norm.     

基于频繁模式树的普遍化关联规则挖掘

提出了基于频繁模式树的普遍化关联规则挖掘算法 MGAR- FP,充分利用频繁模式树的性质 ,避免大量候选模式的生成和频繁模式匹配 ,提高了挖掘的效率和速度 .实验表明 ,算法是有效的 ,比传统的普遍化关联规则挖掘算法Cum ulate快