Comparison of piezo electric particle monitor with laser diffraction technique

A piezo electric particle monitor was used to record droplet size distributions at 5 bars with nitrogen as gas phase and Exxol D60 as liquid phase. The measurements were compared with a laser diffraction technique. A discussion of the limitations of the methods is given. The results show that the piezo electric particle monitor is a good method for measuring droplet size distributions at given conditions.     

An improved simplex-based adaptive evolutionary digital filter and its application for fault detection of rolling element bearings

The de-noising performance and convergence behavior of the adaptive evolutionary digital filter (EDF) are restricted by the factors of constant evolutionary coefficients and taking the reciprocal of average energy of residual signal as the fitness function. In this paper, an improved adaptive evolutionary digital filter based on the simplex method (EDF-SM) is proposed to overcome the shortcomings of the original EDF. A new evolutionary rule was constructed by introducing the simplex-based mutating method and by then combining this with the original cloning and mating methods. The reciprocal of sample entropy was taken as the fitness function and variable evolutionary coefficients were employed. Numerical examples show that the proposed EDF-SM exhibits a higher convergence rate and a better de-noising behavior than the other EDFs. The effectiveness of the proposed method in discovering fault characteristics and detecting faults of rolling element bearings is supported using an experimental test.     

A high accurate static contact angle algorithm based on Hough transformation

The static contact angle for blurry drop images is more intricate to obtain. To improve the accuracy of the Hough transformation for the static contact angle calculation, the water drop images with different volumes are generated by the Laplace equation, and the influence of the volume on the accuracy of the Hough transformation is analyzed. The results reveal that the circle Hough transformation is particularly well suited to the cases with small drop volume. At the same time, the critical water drop volume value corresponding to a contact angle error of 3° is given, a modified Hough transformation algorithm in conjunction with the critical water drop volume is proposed, and at the same time, the accuracy of the static contact angle calculation for blurry water drop images is significantly improved. The proposed algorithm is a powerful approach to estimate the static contact angle for blurry water drop images.     

一种可变步长傅里叶分析器的统计特性分析

可变步长最小均方(Variable step-size LMS,VSS-LMS)算法的傅里叶分析器在稳态误差、收敛速度及追踪能力方面具有优异性能,对其进行全面的统计特性分析具有重要意义.本文基于误差服从高斯分布等假设在平均及均方意义下,推导出描述系统动态特性的差分方程组,完成系统的动态数学建模,进而对系统进行稳态性能分析,给出系统稳态误差关于参考信号频率、系统参数和附加噪声的表达式,为系统应用中的参数选取提供有效指导.仿真表明,本文建立的统计模型与仿真结果具有一致性,验证了分析的有效性.     

锂离子电池循环寿命的融合预测方法

针对传统基于粒子滤波的锂离子电池剩余使用寿命预测方法的不足:过度依赖电池经验退化模型和模型输入变量单一的问题,提出了一种相关向量机、粒子滤波和自回归模型融合的锂离子电池剩余寿命预测的方法。通过相关向量机提取电池历史数据的退化趋势,构建趋势方程替换以往的电池经验退化模型,作为粒子滤波算法的状态转换方程。引入自回归模型的长期趋势预测值,替换观测值构建粒子滤波算法的观测方程。将3种方法相融合估计电池剩余寿命。实验结果表明:融合方法不仅预测精度高而且采用数据驱动的方法避免了构建复杂的电池机理退化模型,通用性强。     

A Modified Dynamic Differential Evolution Algorithm with Greedy Mutation Operation

Dynamic differential evolution （DDE） has been proposed to improve the performance of Differential evolution （DE） by dynamic updating of population. However, the convergence rate of DDE in optimizing a computationally expensive objective function still does not meet all our requirements. A new local search operation, greedy mutation operation, is proposed and embedded into DDE. The greedy mutation operation differs itself from the purely random mutation by considering fitness information. Modifications in mutation ensure that the fitness of base vector is superior to the average fitness of population, which leads to develop offspring that are more fit to survive than those generated from purely random operators. The modified DDE was tested against DE and DDE using five benchmark functions. The results show that the modified DDE converges faster without compromising solution quality.     

虚拟试验系统协议转换模块研制

哈尔滨工业大学自动化测试与控制研究所研发了试验和训练体系结构HIT-TENA平台,用于搭建虚拟试验系统;为了将靶场实物资源接入该系统,研制了基于PCI总线和1553B总线的协议转换模块。采用DSP+FPGA的硬件结构,利用FPGA实现了并行协议帧头识别,利用DSP实现了协议转换。测试表明,该模块能完成协议转换,并将延时降低到1 ms以内,解决了试验设备接入虚拟试验系统时转换效率低下、延时较大等问题。     

基于自适应加权Fisherface算法的人脸识别

提出了一种改进的Fisherface算法。算法首先利用Karhunen-Loeve（K-L）变换降维，在降维的子空间内，根据样本与同类样本间的距离赋予该样本一权值，再用加权后的样本求取类均值，以新的类均值重建类内散布矩阵和类间散布矩阵，从而改进Fisher判别函数。在ORL和Yale人脸库上的实验结果表明，该算法优于传统的主成分分析（PCA）方法和Fisherface方法，并能有效解决小样本情况下训练样本类均值偏离类中心的问题。     

Lithium-ion battery remaining useful life estimation based on fusion nonlinear degradation AR model and RPF algorithm

The lithium-ion battery cycle life prediction with particle filter (PF) depends on the physical or empirical model. However, in observation equation based on model, the adaptability and accuracy for individual battery under different operating conditions are not fully considered. Therefore, a novel fusion prognostic framework is proposed, in which the data-driven time series prediction model is adopted as observation equation, and combined to PF algorithm for lithium-ion battery cycle life prediction. Firstly, the nonlinear degradation feature of the lithium-ion battery capacity degradation is analyzed, and then, the nonlinear accelerated degradation factor is extracted to improve prediction ability of linear AR model. So an optimized nonlinear degradation autoregressive (ND–AR) time series model for remaining useful life (RUL) estimation of lithium-ion batteries is introduced. Then, the ND–AR model is used to realize multi-step prediction of the battery capacity degradation states. Finally, to improve the uncertainty representation ability of the standard PF algorithm, the regularized particle filter is applied to design a fusion RUL estimation framework of lithium-ion battery. Experimental results with the lithium-ion battery test data from NASA and CALCE (The Center for Advanced Life Cycle Engineering, the University of Maryland) show that the proposed fusion prognostic approach can effectively predict the battery RUL with more accurate forecasting result and uncertainty representation of probability density distribution (pdf).     

Fully Pipelined Soft Vector Processor as a CPU Accelerator

FPGA based soft vector processing accelerators are used frequently to perform highly parallel data processing tasks. Since they are not able to implement complex control manipulations using software, most FPGA systems now incorporate either a soft processor or hard processor. A FPGA based AXI bus compatible vector accelerator architecture is proposed which utilises fully pipelined and heterogeneous ALU for performance, and microcoding is employed for reusability. The design is tested with several design examples in four different lane configurations. Compared with Central processing unit (CPU), Digital signal processor (DSP), Altera C2H tool and OpenCL SDK implementations, the vector processor improves on execution time and energy consumption by factors of up to 6.6 and 6.4 respectively.