Shenyang Institute of Automation,Chinese Academy Of Sciences
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A novel attention-based domain adaptation model for intelligent bearing fault diagnosis under variable working conditions
No full textIn recent years, transfer learning technology has developed rapidly and has been widely used in bearing fault diagnosis. Most existing methods mainly align the overall feature distribution of the signal samples across the source and target domains. However, the transferability of each signal and each segment of a signal sample is different. Therefore, in this paper, a novel attention-based domain adaptation model (ADA) is proposed. The ADA model consists of a feature extractor and an ADA module. The feature extractor is built by separable convolution with channel attention module and length attention module to improve the reliability of feature learning. The ADA module consists of two parts, the local ADA module and the global ADA module to enhance the model's domain adaptation ability by focusing on the signals and signal segments with better transferability. The experimental results show that the ADA model is superior to other intelligent fault diagnosis methods based on transfer learning under variable working conditions
Maneuvering simulation of multi-AUV self-propulsion in tandem
No full text针对现有的多水下机器人编队的水动力性能分析仅限无桨模型、定常航行的现象，无法解决真实编队螺旋桨滑流对水下机器人运动影响问题，本文提出采用离散螺旋桨的类物理数值方法，对多水下机器人自航编队的非定常操纵运动进行模拟。相对于无桨拖曳编队的领航者对追随者的吸力作用，自航编队表现出不同的相互作用：领航者对追随者有斥力作用，导致追随者阻力增加、速度降低、能耗增加、编队间距增加；此外，领航者的滑流会引起追随者产生周期性，时变的横滚力矩。该方法可用于分析多体耦合流场干扰，提高多体协同作业的安全性和能源预报精度。</p
Differential evolution algorithm with dynamic multi-population applied to flexible job shop schedule
No full textThis article proposes a novel differential evolution algorithm based on dynamic multi-population (DEDMP) for solving the multi-objective flexible job shop scheduling problem. In DEDMP, at each generation, the whole population is divided into several subpopulations by the clustering partition and the size of the subpopulation is dynamically adjusted based on the last search experience. Furthermore, DEDMP is adaptive based on two search strategies, one with strong exploration ability and the other with strong exploitation ability. The selection probability of each search strategy is also dynamically adjusted according to the success rate. Furthermore, the proposed algorithm adopts newly designed mutation and crossover operators and it can directly generate feasible solutions in the search space. To evaluate the performance of DEDMP, DEDMP is compared with some state-of-the-art algorithms on benchmark instances. The experimental results show that DEDMP is better than or at least competitive with other outstanding algorithms.</p
Recent advance in cell patterning techniques: Approaches, applications and future prospects
No full textCell patterning technology is an effective technique to understand cell behaviors by precisely controlling the position of cells revealing the major contributions of cells in basic and applied biological research in vitro. Therefore, this technology has led to the development of various micro-nano manufacturing methods. In recent years, various methods have been continuously improved and innovated based on existing methods to overcome shortcomings. We outline the latest developments in cell patterning technology, including stencil patterning, microfluidics-based on traps and droplets, and surface modification techniques such as photolithography, microcontact printing, and laser technology. In the end, we introduce the application and future prospects of cell patterning in biological research.</p
A Legorization method based on 3D color printing trajectory
No full textIn this paper, a Legorization method which can reconstruct LEGO model with complex internal and external structures from 3D color printing trajectory is proposed. Different from voxelization methods, by combining advanced adaptive slicing algorithm with building “high-resolution” regions with thin plates, the reconstruction accuracy of initial LEGO units can be guaranteed. Furthermore, the tree structure is employed for automatically generating support structures which can be converted into LEGO support structures. By adopting split assembly appropriately and implementing combination of these parts accurately, the reducing supporting structures can be further simplified. In order to optimize the Legorization scheme, a machine learning method is used to guarantee the quality and efficiency of the reconstruction work. Complex LEGO models are provided to demonstrate the effectiveness of the proposed method.</p
Study on Power Consumption and Stealing Law of Large-Scale Low Voltage Power Supply Area
No full text针对国内外在220 V和380 V供电电压的低压地区电力消耗的研究较少,很难探究实时线损的问题。对供电、用电、线损、窃电4个方面进行数据分析,建立统计模型与聚类模型,探索电力消费和窃电的规律。利用时间序列分析、频谱分析、概率密度函数、互补累积分布函数的统计模型进行分析。结果表明窃电用户用电周期是正常用户的2倍,窃电用户的日均用电量大于正常用户,窃电用户在台区线损率大于40%时数量激增,线损率到达65%时数量放缓,可以优先排查此区间的台区。基于时间序列相似度度量和k-means聚类相结合的聚类模型,将566个台区365维的时间序列聚类得到6类不同的台区线损率模式,并通过核密度估计对比了他们的分布差别,可以帮助快速排查出重点窃电台区并监测线损率改善的情况。</p
System Error Calibration in Large Datasets of Wireless Channel Sounding for Industrial Applications
No full textChannel impulse response (CIR) datasets, which represent the characteristics of wireless channels, play a vital role in industrial applications. Unfortunately, systematic errors have been discovered within CIR datasets. These errors have undesirable effects in wireless localization, physical layer security, and related applications. In addition, existing CIR calibration methods do not consider applicability to industrial scenarios. To address this concern, two channel sounder error calibration (CSEC) methods are proposed. The first CSEC method based on phase compensation (CSEC-Phase) extracts the direct path signal to estimate errors to avoid interference from rich multipath signals for stationary measurements in complex industrial environments. Moreover, to solve the problem of the inability to estimate the CIR error in mobile measurements due to the rapid dynamic change of the channel, a second CSEC method based on carrier frequency recovery (CSEC-Frequency) is proposed that extracts the frequency offset of the system clock to compensate for systematic error utilizing the stability of clock drift. Furthermore, the L1-norm distance metric is employed to measure the differences between CIRs and evaluate the calibration performance. Our results reveal that the proposed CSEC methods are effective on diverse CIR datasets measured by different11The MATLAB code of the CSEC methods has been shared on GitHub: https://github.com/QiWang-GH/Industrial-Wireless-Channel-Sounding-Error-Calibration-IW-CSEC. equipment in different scenarios.</p
一种用于空间站科学实验柜振动试验的夹具装置
No full text本发明涉及航天技术领域，尤其涉及一种用于空间站科学实验柜振动试验的夹具装置。用于空间站科学实验柜振动试验的夹具装置包括底板及分别设置在底板两侧的第一支撑组件和第二支撑组件，底板、第一支撑组件和第二支撑组件形成U型结构，第一支撑组件和第二支撑组件相向设置以夹持科学实验柜，第一支撑组件和第二支撑组件均与底板活动连接，以调节第一支撑组件和第二支撑组件之间的距离。由此，该用于空间站科学实验柜振动试验的夹具装置，便于科学实验柜的安装同时便于对科学实验柜在振动试验过程中进行状态检查，也能够预留出后续科学实验柜减振设计的空间，从而降低了科学实验柜在振动试验中的试验成本
一种小尺寸精确力矩拧紧单元
No full text本实用新型公开了一种小尺寸精确力矩拧紧单元，属于自动化精确拧紧设备技术领域，该拧紧单元包括电机、减速机、锥齿轮组和拧紧套筒；其中：所述电机与减速机相连，电机提供动力通过减速机增强扭矩后传动到锥齿轮组上，锥齿轮组带动拧紧套筒动作；所述锥齿轮组把水平运动转变为竖直的旋转运动。该拧紧单元主要应用用于狭窄空间环境下的精确拧紧装置，能够实时闭环测量拧紧力矩，能够精确的测量拧紧套筒输出的转角，并能提供封闭内腔环境下的拧紧过程可视化监控，全部功能均集成于拧紧机构内部及壳体表面，结构紧凑
一种水下机器人用无刷电机控制器
No full text本实用新型涉及一种水下机器人用无刷电机控制器，包括600V直流电，稳压模块，三相全桥功率模块，电流检测模块，绝对值处理模块，转子位置检测模块，控制量死区控制模块和CPU控制模块。所述稳压模块、三相全桥功率模块、无刷直流电机依次连接；电流检测、绝对值处理模块、CPU控制模块依次连接；速度给定模块、正反转控制模块、绝对值处理模块、CPU控制模块依次连接；所述CPU控制模块还通过驱动电路与三相全桥功率模块连接。本实用新型结构简单，模拟量输入控制，自动换向，并能够进行过流保护，系统简单，可靠性高，成本低，本实用新型也可以用于其他水下机器人的推进器驱动系统