This paper takes the motion units of the series-parallel machine tool (SPMT) as the basic research objects. Combined with the meta-action theory, the FMA-MBS structure model is proposed to describe the spatial structure relationships and motion transfer relationships of SPMT. Based on the simplified model, the kinematics characteristics of the machine tool are gradually researched from four layers: joint layer, limb layer, subsystem layer, and the whole machine. According to the twist system of limbs and moving platform, the parallel motion system can be simplified into a virtual motion chain with specific constraints. Then, the kinematics model of SPMT is constructed in twist exponential form. By introducing two virtual degrees of freedom (DOFs), the unified expressions of active and passive joint errors are obtained. All motion systems error models are derived based on three basic error terms of the meta-action layer. Based on the error mapping relationships, the precision of the machine tool can be calculated and evaluated. In order to illustrate the applicability and effectiveness of the proposed method, a sample library of common SPMTs and a case study of a 5-axis series-parallel machining center are provided.

The process of recovering high-resolution images from one or more degraded low-resolution images is known as super-resolution reconstruction. The present super-resolution (SR) deep learning technique has certain limitations, because the deeper the network layer, the higher the training cost and time consumption. This paper, based on SRCNN, revamped the three-step reconstructed process of SRCNN by including VGG and residual ideas. Enhancing its network structure by utilizing subpixel convolution approach which can replace the step of image preprocessing and upscale in SRCNN algorithm. When comparing the reconstructed pictures of Set5, Set14, BSDS100, Urban100, and Manga109 data sets, the revised SRCNN structure outperforms the original SRCNN by 1.1dB in Peak Signal to Noise Ratio (PSNR) and 0.026 in structural similarity (SSIM). When compared to other popular SR network except for SRCNN, the improved reconstructed network has fewer network layers, is easier to train, and produces higher reconstructed image quality than the original SRCNN.

Color constancy is an important prerequisite for visual tasks such as recognition, segmentation, and three-dimensional object reconstruction. We proposed a multi-channel feature-confidence-weighted network to enable the computer vision systems to perceive color constancy. As a result, the network could fully extract the features in the images while reducing the number of network layers and model parameters. The multi-channel confidence-weighted method employed the features in each channel that could provide more information for light source estimation to accurately estimate the light source in the global scene. Experimental results on the reprocessed ColorChecker and NUS-8 datasets show that the proposed algorithm, which weights the confidence of features in multiple channels, outperforms its counterparts in terms of all evaluation indexes and thus has higher accuracy and robustness. As such, this algorithm can be applied to the tasks of computer vision requiring color correction.

The purpose of super-resolution reconstruction is to reconstruct a high-resolution image from one or more low resolution images. In this paper, we propose an improved super-resolution generative adversarial networks based on the attention model. The attention model can be used to extract the important features and suppress the unimportant features, so as to ensure the quality of network reconstruction and optimize the network structure of the generator in the generative adversarial networks (GAN). The experimental results show that on the Set5 datasets, we could use less residual block to train and the spending time of reconstruction is less by using the attention model. That also means the fewer parameters and the less calculation. The images selected on Set14 and BSD100 datasets are reconstructed, and the reconstructed time is also shortened.

In this paper, the multi-level grey system theory method is used to evaluate the economics of the circulating water system. Firstly, the influencing factors of each part are divided into different levels, and the weights of each factor are determined by using the analytic hierarchy process. Secondly, the influencing factors are divided into five commentary categories based on the Grey system theory. The whitening weight function of the grey class is established, and then the whitening value is calculated. Finally, the weight of the circulating water system belongs to each grey class, and the economic performance of the cooling water system is reasonably and objectively evaluated. Through the calculation and description of a specific example of the cooling water system, the economics of the whole cooling water system and various links are obtained. The economic evaluation results obtained by the analysis are in line with objective laws and provide a new way for the economic evaluation of the cooling water system.

针对复杂机械产品在生产运作过程中的运动性能难以监测和控制的问题,提出一种基于数字孪生的运动调控方法.该方法以元动作理论为基础,建立机械产品基于数字孪生的运动研究六维结构模型,并规划了数字孪生驱动的运动性能调控模式.根据元动作链的运动特性,实施基于动作层的数据监测技术,解决了传感器的选择和布置问题.利用多维仿真软件和数字孪生技术强大的虚实交互融合能力,制定了具体的建模、仿真和运动优化技术方法.最后,以某六自由度工业机器人为例验证了该方法的合理性和实用性.结果表明,数字孪生驱动的运动性能调控机制适应性好,鲁棒性强,实现了机器人运动性能的精细化管理.

2D CNNS for video-based action modeling ignore the temporal information and treat the multiple frames analogously to channels. In view of this, a mixed convolution structure implemented with ResNet-18 residual network is designed for video feature extracting. The 3D convolution and the (2+1)D convolution are interleaved in sequence throughout the network. Firstly, 2D convolution is performed on input multiple video frames one by one in the spatial. Then, 1D convolution of temporal is performed on the output of 2D convolution. Finally, 3D convolution is performed for spatiotemporal modeling simultaneously. Results show that the mixed convolution structure enhances the transmission of temporal information, improves the ability of video feature extraction and the action recognition accuracy obviously.

This paper presents the solution to evaluate and predict machining precision of a multi-axis computer numerical control (CNC) machine tool. The "function-motion-action" method is used to describe the motion relationships of a multi-axis CNC machine tool, and the multi-body system structure model of the machining system is further constructed. By analyzing the motion process of the machine tool based on the meta-action layer and considering the motion transfer relations in meta-action chains, the kinematic models of each motion shaft are established in twist exponential form. According to the structural and kinematic relationships of these motion shafts, the kinematic and kinematic error models of the machine tool can be easily obtained. Then, the distance error formula is used to deduce the general model of machining allowance error. A simulation test and practical experiment are performed on a type of CNC controlled 5-axis machining center. The experiment results show that the proposed method is universal, and it can greatly simplify the kinematic analysis of multi-axis CNC machine tools. (C) 2019 Elsevier Ltd. All rights reserved.

针对故障诊断软件代码量大、推理规则多及测试耗时大的问题,提出了基于正交试验法提取有代表性推理规则的测试方法.分析了故障诊断软件的需求特性,介绍了正交试验法的理论依据,阐述了使用正交试验法在故障诊断软件测试中提取代表性推理规则的方法,并说明了根据提取出来的推理规则进行测试用例设计的思路和具体实施效果.

鉴于高空作业平台对调平系统作业平稳性、可靠性及高精度的迫切需求,研究了蓄能器对调平系统压力冲击及压力波动的影响规律,旨在为优化调平系统性能提供参考依据.首先,通过基于蓄能器吸振的调平系统简化模型,理论分析了蓄能器主要参数对蓄能器性能的影响,进而分析了压力冲击及压力波动的作用机理;其次,结合蓄能器作用下的调平系统仿真模型,研究蓄能器对调平系统动态稳定性的影响规律.理论分析与仿真结果均表明:合理配置蓄能器并选择其主要参数,能够使蓄能器对压力波动和压力冲击的抑制效果最大化,有效提高调平系统性能.

为提高电机轴承的故障诊断精度,在深入研究核Fishier判别分析的基础上,对其进行了改进,并提出基于独立特征选择核Fishier判别分析(IFS-KFDA)的电机轴承故障诊断方法.该方法首先从多个角度构建了原始高维故障特征集,在此基础上,利用独立特征选择核Fisher判别分析为轴承每两类故障状态独立选择敏感特征集,使获得的敏感特征对故障状态具有更好的表征作用,同时还有效地排除乐原始混合特征集中的非敏感特征的干扰.轴承故障诊断实例验证了方法的有效性.

In this article, 17-4PH metal powder was used as raw material to study the effects of the injection position and MIM (metal powder injection molding) thermal debinding temperature on the rocker arm. By simulation, it was found that different injection schemes have obvious effects on the filling time, density, blowhole, and injection stress of parts. In addition, when the termination temperature of the thermal debinding was 820 °C, the presintering effect could be achieved. When the intermediate process temperature was 450 °C, the polyethylene component remained in the sample. According to the TG and DSC curves of the solvent debinding feedstock, it was effective to avoid the occurrence of the residue binder when the intermediate process temperature increased to 500 °C.

To improve the accuracy of speed hydraulic system and overcome the nonlinear time -varying problem ,the fuzzy control strategy for the motor speed was proposed .The power source was the servo motor ,which drove the dosing pump ,and then the fuzzy controller of the system was designed .Based on Labview test and control platform ,the model of the fuzzy controller for the motor speed is evaluated .In order to compare the control effects of traditional PID and fuzzy control system ,the experiment for dynamic response and load disturbance rejection capability were carried on respectively in the two control strategies .The results show that the robustness of the fuzzy control is better than traditional PID ,but the dynamic response characteristics are similar .

[目的] 为改善高空作业平台的调平性能,研究长管道效应对调平性能的影响.[方法] 通过建立长管道模型,分析了影响调平性能的管道参数,并结合长管道作用下的调平系统仿真模型,分别研究管道材质、长度、直径及布管方式对调平性能的影响规律.[结果] 硬管材质能够较软管材质使系统响应时间缩短0.4~0.6 s;管道长度由1 m增加至40 m可使系统响应时间由0.05 s延长至0.3 s,压力损失由0.6 bar增大至24.8 bar;管道直径由5 mm增大至20 mm,使调平稳定时间由1.1 s延长至2.2 s,压力损失由69.9 bar减小至1.7 bar;阀前布管较阀后布管加快系统响应时间约0.2 s,但易引起压力冲击.[结论] 长管道效应对高空作业平台调平性能的影响显著,长管道参数化分析形成调平系统的优化布置及参数选择原则,对高空作业平台的调平性能改善提供了参考.

In recent years, with the combination of “Internet + finance”, traditional supply chain finance has also accelerated the online operation, and the risks it faces have gradually been exposed. This paper will use risk management theory, select risk identification and risk measurement methods, to deeply analyze the Internet supply chain financial operational risk. Enhance the cognition and emphasis of financial institutions on operational risk.

Aimed at the problem that the viscosity of biodegradable synthetic ester oil changes with the varying environmental parameters under deepening environment,such as temperature and pressure,the deepening environment model was established with environmental pressure and sea water temperature as environmental parameters,and the model of oil viscosity was deduced by using the "modal equation".By analyzing the error of theoretical results of ISO VG 32 and ISO VG 46,their maximum errors are obtained by 6.9％ and 8.4％,respectively,which verifies the validity of the model.Based on the above model,a theoretical analysis model of oil viscosity using sea depth as the independent variable was proposed,which reveals three-step dynamic change rules of oil viscosity with the increasing of dive depth,including increasing rapidly,transition adjusting and increasing steadily,respectively.The changing rule of oil viscosity characteristics under deepening environment lays theoretical foundations for selection of underwater hydraulic medium and analysis of the performance of hydraulic equipment in deepening environment.

为提高工作平台调平系统的精度,对调平机构与变幅机构间的速度匹配规律进行了研究.提出以变幅输出角速度和调平输出角速度为比值的匹配性系数,给出以该系数为依据的衡量作业平台输入-输出匹配性好坏的匹配性准则.建立了高空作业车机电液虚拟样机模型,分别分析了平台调平系统与下臂变幅机构以及上臂变幅机构之间的匹配规律.结果表明:匹配性系数越接近于1,匹配程度越高.臂架启动阶段,匹配性系数接近1的速度越快,平台倾角越小;臂架举升阶段,匹配性系数的变化趋势与平台倾角变化趋势一致.验证了依匹配性系数为依据的匹配性准则的合理性和有效性,为评价调平系统的动态性能的优劣提供了一种有效方法.

In order to improve the flow control precision of hydraulic system and eliminate the steady-state error, the flow PID closed loop control system was designed. Through the measurement and control program written in Labview software, the difference between flow measurement value and the target value was inputted the PID controller. The speed control voltage of servo motor PID controller was outputted through PID controller. By adjusting the rotational speed of servo motor, the actual output flow can reach the set value. The experimental results show that the actual flow value can follow and respond to the change of target flow. The flow closed loop control system has strong anti interference ability for the step, sine and slope pressure disturbance signal.

作为机电液系统的输入源信号,电机电流信号具有容易获取的优点,是对机电液系统进行状态分析的理想信息来源.利用三相电机的电流信号对机电液系统的故障进行分析,并采用小渡变换作为特征提取方法从电流信号中提取设备的故障特征.最后通过试验结果证明了所提方法有效性.

对斗容量1 m3反铲液压挖掘机工作装置进行了设计与计算,确定了工作装置主要参数,分析了理论挖掘力和切削阻力的匹配关系,校核了动臂油缸提升力和各油缸的闭锁力,验证了设计的合理性.