联合时变低通与改进形态学滤波的智能在线称量方法研究

针对检重秤在复杂工业生产环境下,受机械传动、被测物体自身振动和外界随机扰动影响导致的传感器输出信噪比低、称量准确性难以满足要求等问题,提出一种联合时变低通与改进形态学的快速数据处理新方法:时变低通滤波器作为一级滤波,通过在信号跃变时,迭代优化滤波器参数,使边沿信号得以快速响应,有效消除冲击干扰,并抑制称重信号在滤波过程中的相位失真;然后采用改进形态学滤波器进行二级滤波,通过选择零值线性结构元素,并优化结构元素长度以及操作算子的权值系数,加快了动态称重的响应速度。实验结果表明,该方法能有效抑制各类干扰影响,提高测量准确度,最终实现运行速度达120 m/min,最大秤量400.0 g,满足国家标准《GB/T 27739—2011自动分检衡器》XIII级要求的检重秤搭建。     

Dynamic reliability-based robust design optimization with time-variant probabilistic constraints

With the increasing complexity of engineering systems, ensuring high system reliability and system performance robustness throughout a product life cycle is of vital importance in practical engineering design. Dynamic reliability analysis, which is generally encountered due to time-variant system random inputs, becomes a primary challenge in reliability-based robust design optimization (RBRDO). This article presents a new approach to efficiently carry out dynamic reliability analysis for RBRDO. The key idea of the proposed approach is to convert time-variant probabilistic constraints to time-invariant ones by efficiently constructing a nested extreme response surface (NERS) and then carry out dynamic reliability analysis using NERS in an iterative RBRDO process. The NERS employs an efficient global optimization technique to identify the extreme time responses that correspond to the worst case scenario of system time-variant limit state functions. With these extreme time samples, a kriging-based time prediction model is built and used to estimate extreme responses for any given arbitrary design in the design space. An adaptive response prediction and model maturation mechanism is developed to guarantee the accuracy and efficiency of the proposed NERS approach. The NERS is integrated with RBRDO with time-variant probabilistic constraints to achieve optimum designs of engineered systems with desired reliability and performance robustness. Two case studies are used to demonstrate the efficacy of the proposed approach.     

LTE上行接收分集中一种新的判决反馈检测算法

针对快速时变信道,提出了一种新的联合信道估计和符号判决反馈检测算法应用于LTE上行接收分集.新算法对OFDM数据符号进行硬判决,并利用硬判决结果对该符号上的信道进行估计,估计结果用于相邻数据符号的均衡和解调.分析和仿真结果表明：在高信噪比、快速移动环境下,新算法相对线性插值算法具有较好的性能,而且具有较高的实用性.     

基于强震记录的建筑结构动力特性识别

利用喜来登环球旅馆于1994年北岭地震中获得的强地震反应观测记录,运用卡尔曼滤波识别了该旅馆结构刚度在地震过程中的时变规律,并对该结构的表现做出初步解释。本文工作可作为进一步研究喜来登旅馆这类建筑结构实际抗震性能的基础。     

一种基于优化参差比的改进MTI滤波器

杂波的抑制 ,无论是从抗干扰还是提高雷达系统改善因子来说都是必不可少的。抑制杂波的同时为了避免陷入盲速区的目标损失过大 ,提出了一种基于优化参差比的MTI滤波器 ,该滤波器可在杂波谱中心形成随杂波散射元均方根速度展宽的凹口以抑制杂波 ,并利用参差脉冲将盲速推到三倍音速以外 ,而且通过最优参差码的选择使第一零点尽可能的浅 ,从而防止陷入凹口的弱目标丢失 ,最后通过对搜索最优参差比的简化 ,使运算量至少减少一半。仿真结果和性能分析验证了该算法的可行性和有效性     

Minimum variance control and performance assessment of time-variant processes

This paper is concerned with (1) an explicit solution of a minimum variance control law for linear time-variant (LTV) processes in the transfer function form, and (2) performance assessment of LTV processes using minimum variance control as the benchmark. It is shown that there exists a time-variant, absolute lower bound of process variance that is achievable under LTV minimum variance control and can be estimated from routine operating data. This lower bound can subsequently be used to assess the benefit of implementing LTV control such as adaptive control. The proposed methods are illustrated through simulated examples and an industrial case study.     

时变主轴转速再生切削系统的动态响应特征

考虑多重再生切削效应,建立了在时变主轴转速下再生切削系统的时滞动力学模型及递推求解算法,该算法适用于主轴转速变化的任意轨迹.将再生切削系统相继两转的动态响应作为观测数据,提出了基于互四阶累积量的谐参数联合估计的TLS-ESPRIT方法.根据该方法,研究了时变主轴转速对再生切削系统动态响应的影响,揭示了再生切削系统动态响应的频率、相继两转切削间的相移和互功率等谐参数对主轴转速依赖的一些新特征.     

UUV平台OFDM水声通信时变多普勒跟踪与补偿算法

针对传统多普勒估计和补偿算法在基于无人水下航行器(UUV)的正交频分复用(OFDM)水声移动通信中难以准确跟踪时变多普勒因子并对其进行快速实时补偿的缺陷,提出了一种基于时频联合搜索的新的多普勒跟踪与快速补偿算法。利用梳状导频结合频域变采样技术搜索OFDM符号在不同多普勒因子下的信道频域响应,借助匹配追踪技术对信道估计结果进行稀疏度评估,选择稀疏度最佳的信道响应对应的多普勒估计对信号进行快速补偿。经蒙特卡洛仿真及海试试验证明,该方法能够有效实现对基于UUV平台的时变多普勒实时追踪和快速补偿,保证稳健的OFDM水声移动通信。     

不确定时变线性系统的鲁棒一致渐近稳定的扰动界

不确定时变线性系统的鲁棒一致渐近稳定的扰动界奚宏生（中国科学技术大学自动化系合肥２３００２６）关键词不确定时变线性系统，鲁棒一致渐近稳定，奇异值．ｌ引言在文献［１—３］中利用状态空间方法研究了结构不确定定常线性系统参数扰动的稳定区域．本文利用时变矩阵...     

适用于水声信道新的盲均衡算法及仿真

对于时变水声信道,由于随机相位失真,常数模算法(constant modulus algorithm,CMA)的误码性能将严重下降.在基于一种双模式盲均衡算法的基础上,提出了一种与相位相关的新的盲均衡算法(NCMA),并用QAM系统进行了计算机仿真.将仿真结果与双模式算法进行比较,显示出该算法性能优于双模式算法,能够达到对信号相位失真的恢复,并且收敛性能优于双模式算法.