Power Matching and Energy Efficiency Improvement of Hydraulic Excavator Driven with Speed and Displacement Variable Power Source

Mobile machinery energy efficiency and emission pollution are the national and worldwide issues. This paper contributes in solving these problems by applying a speed variable power source. Unfortunately, almost all of the speed variable systems have the dynamic response problem when the motor starts with full load or heavy load. To address this problem, a hydraulic accumulator is used to balance the load of the power source for assisting starting of the motor and a matching method combined with speed and displacement control of the pump is proposed to improve the energy efficiency and dynamic performance simultaneously under different working conditions. Also, the power source/valve combined control strategy of an independent metering system is designed to realize flow matching of the whole system. Firstly, a test system is established to study the dynamic performance and energy efficiency of the speed variable power source with an auxiliary accumulator. Working performance and energy consumption of the power source under different rotating speeds and different loads are studied. And then, the hydraulic excavator test rig with the proposed system is constructed. Furthermore, the working performance of the excavator with the speed-fixed and speed-variable strategy are studied comparatively. Results show that, compared with fixed-speed strategy, the electric power consumption during the idle period and partial load condition can be reduced about 2.05 kW and 1.37 kW. The energy efficiency of speed variable power source is about 40%-71%, which is higher than that of the fixed-speed power source by 3%–10%.

Acoustic sound speed profile inversion based on orthogonal matching pursuit

The estimation of ocean sound speed profiles(SSPs)requires the inversion of an acoustic field using limited observations.Such inverse problems are underdetermined,and require regularization to ensure physically realistic solutions.The empirical orthonormal function(EOF)is capable of a very large compression of the data set.In this paper,the non-linear response of the sound pressure to SSP is linearized using a first order Taylor expansion,and the pressure is expanded in a sparse domain using EOFs.Since the parameters of the inverse model are sparse,compressive sensing(CS)can help solve such underdetermined problems accurately,efficiently,and with enhanced resolution.Here,the orthogonal matching pursuit(OMP)is used to estimate range-independent acoustic SSPs using the simulated acoustic field.The superior resolution of OMP is demonstrated with the SSP data from the South China Sea experiment.By shortening the duration of the training set,the temporal correlation between EOF and test sets is enhanced,and the accuracy of sound velocity inversion is improved.The SSP estimation error versus depth is calculated,and the 99%confidence interval of error is within±0.6 m/s.The 82%of mean absolute error(MAE)is less than 1 m/s.It is shown that SSPs can be well estimated using OMP.

Research on the measurement of belt speed by video in coal mine based on improved template matching algorithm

In order to improve the intelligence of video monitoring system of belt and make up the deficiency of higher failure rate and bad real-time performance in the traditional systems of measurement of belt speed, according to the fact that the light of coal mine is uneven, the strength of light changes greatly, the direction of belt movement is constant, and the position of camera was fixed, various algorithms of speed measurement by video were studied, and algorithm for template matching based on sum of absolute differences （SAD） and correlation coefficient was proposed and improved, besides, the tracking of feature regions was realized. Then, a camera calibration method using the invariance of the cross-ratio was adopted and the real-time measurement of belt speed by the hardware platform based on DM642 was realized. Finally, experiment results show that this method not only has advantages of high precision and strong anti-jamming capability but also can real-time reflect the changes of belt speed, so it has a comprehensive applicability.

An Algorithm for the Optimal Matching Speeds of Pass enger and Freight Trains in Mixed Operations

This paper models the calculation of the optimal matching speeds of passenger and freight trains with various stage control methods for speed in mixed operations, presents a algorithm for the solution and justifies it with a practical example.

Temperature-Based Fan Speed Optimization Strategy

As energy efficiency and indoor comfort increasingly become key standards in modern residential and office environments,research on intelligent fan speed control systems has become particularly important.This study aims to develop a temperature-feedback-based fan speed optimization strategy to achieve higher energy efficiency and user comfort.Firstly,by analyzing existing fan speed control technologies,their main limitations are identified,such as the inability to achieve smooth speed transitions.To address this issue,a BP-PID speed control algorithm is designed,which dynamically adjusts fan speed based on indoor temperature changes.Experimental validation demonstrates that the designed system can achieve smooth speed transitions compared to traditional fan systems while maintaining stable indoor temperatures.Furthermore,the real-time responsiveness of the system is crucial for enhancing user comfort.Our research not only demonstrates the feasibility of temperature-based fan speed optimization strategies in both theory and practice but also provides valuable insights for energy management in future smart home environments.Ultimately,this research outcome will facilitate the development of smart home systems and have a positive impact on environmental sustainability.

Resource Allocation in D2D-Aided High-Speed Railway Wireless Communication Systems： A Matching Theory Approach

With the rapid deployment of high speed railway(HSR) worldwide,both safety operation and comfort experience can be desired to evolve into a future era of intelligent transportation system.To eliminate boredom and provide entertainment for passengers,an intranet for internal communications among passengers named as onboard social network system(SNS) is needed.In this paper,the latest progress in HSR network architectures and technology building blocks are discussed to enable the implementation of the SNS.Meanwhile,based on the device-to-device(D2 D) communication technology for proximal information interaction,SNS can be efficiently facilitated.A dynamic resource allocation algorithm is proposed to maximize the total utility of the onboard SNS,which is solved with the matching theory method.Simulation results verify the convergence and efficiency of the proposed algorithm.

Domain Decomposition and Matching for Time-Domain Analysis of Motions of Ships Advancing in Head Sea

A domain decomposition and matching method in the time-domain is outlined for simulating the motions of ships advancing in waves. The flow field is decomposed into inner and outer domains by an imaginary control surface, and the Rankine source method is applied to the inner domain while the transient Green function method is used in the outer domain. Two initial boundary value problems are matched on the control surface. The corresponding numerical codes are developed, and the added masses, wave exciting forces and ship motions advancing in head sea for Series 60 ship and S175 containership, are presented and verified. A good agreement has been obtained when the numerical results are compared with the experimental data and other references. It shows that the present method is more efficient because of the panel discretization only in the inner domain during the numerical calculation, and good numerical stability is proved to avoid divergence problem regarding ships with flare.

A modified image matching algorithm based on robust Hausdorff distance

Hausdorff distance measure is one of the widely adopted feature-based image matching algo- rithms due to its simplicity and accuracy. However, it is considered that its robustness still needs to be improved. In this paper, various forms of original and improved Hausdorff distance （HD） and their limitations are studied. Focusing on robust Hausdorff distance （ RHD）, an improved RHD with an adaptive outlier point threshold selection method is proposed. Furthermore, another new form of the Hausdorff distance which possesses the merits of RHD and M-HD is prsented. Finally, a recur- sire algorithm is introduced to accelerate the image matching speed of Hausdorff algorithms. Exten- sive simulation and experiment results are presented to validate the feasibility of the proposed Haus- dorff distance algorithm.

Design Analysis and Optimal Matching of a Controllable Pitch Propeller to the Hull and Diesel Engine of a CODOG System

The optimal matching of a propeller to the hull and the diesel engine of the combine diesel or gas (CODOG) system is a critical design analysis in ship building. In this research work, a controllable Pitch Propeller (CPP) was considered whereby the pitch was varied, but only the extreme pitch set the limit of operation and matching was done with the extreme pitch condition. It considers the performance analysis of the propeller, the hull and the engine both in design and off design conditions. Without propulsion a vessel built cannot move and so choosing the right propeller to match the hull and engine is very vital. The various processes involved in the matching of the propeller to the diesel engine and hull of the vessel are considered, in order to achieve optimal performance of the vessel. A Java program (prop-matching) was developed to facilitate the matching process. The graphs obtained are used to determine the matching point at corresponding speed and power. The thrust and torque developed under different conditions as well as their significance, considering the fact that the propeller is a CPP. The engine response in transient conditions in reaction to the turbo charger was considered, the matching graph of the turbo charger compressor was discussed, and the calculated mass flow rate with various engine speeds and boost pressure were also discussed. This program was further used in matching the propeller to the hull and diesel or gas engines of a F90 frigate. The corresponding propeller rpm and engine power with pitch ratios from the program were similar to those from the design of the frigates. The various thrust and torque coefficients and open water efficiency all correspond to the simulated results of those of the naval frigate.

城市轨道交通全自动运行线路多专业速度控制与匹配设计研究

城市轨道交通多专业间的协调性是决定能否充分实现预期能力、发挥投资效益的关键环节,列车运行速度是其中一个重要方面,是城市轨道交通技术装备、技术标准、运营管理水平的重要标志。针对不同专业速度控制存在的重叠防护问题,通过剖析通信、信号、车辆、线路、环境等对全自动运行(FAO)线路列车运行速度的限制,提出列车自动运行(ATO)模式、列车自动防护(ATP)模式、蠕动模式和洗车模式4种典型运行模式下的速度匹配控制方案,讨论了根据线路等级速度拟定正线区间结构设计速度、车辆构造速度、车辆超速防护触发速度、车辆最大动态包络线计算速度、最高ATP顶篷速度、最高ATO目标速度的方法,并给出多专业匹配设计关键速度建议值。同时借助仿真手段,结合不同站间距设置与最短时间速度曲线计算,进一步针对速度等级为80,100 km/h以及120 km/h的线路分别讨论了站间距的匹配设计,建议三者站间距分别不少于1.0,1.4 km以及2.5 km。开展多专业速度控制与匹配设计的优化,有助于最大化发挥系统和设备性能,保证线路整体运营水平。

电动叉车动力传动系统优化设计

为了提高电动叉车的续航里程及动力性能,提出了加装两挡变速器的传动方案。首先,基于驱动电动机的外特性与效率特性提出了两挡传动系统参数匹配方法;其次,以某型电动叉车为研究对象,对其驱动系统进行了改进:在不改变驱动电动机各项参数的基础上,将传动系统由一挡改为两挡,并对主减速比及变速器的两挡减速比进行匹配;最后,利用ADVISOR软件对电动叉车进行了平衡重式叉车循环工况仿真分析。结果显示,在不改变驱动电动机各项参数的基础上加装两挡变速器,可提升整个电动叉车的动力性和经济性;车速由0加速到最高车速的时间缩短了0.4s,满载爬坡度提高了2.5%,2小时叉车等效工况循环的电池能耗降低了3.5%。

转速对航空动力装置动力性能和经济性能的影响

为探究发动机转速对某中空长航时无人机动力装置的动力性能和经济性能的影响,结合发动机速度特性曲线、耗油率特性曲线、高空特性曲线及螺旋桨效率曲线,在某无人机飞行速度范围内,选取典型发动机油门匹配不同发动机转速,通过理论计算与试验相结合的方法,评估动力性能和经济性能的变化情况。研究表明:对于所研究的航空动力装置,在所研究的发动机转速范围内,推力随着发动机转速的增加而增大,单位推力耗油率则随着发动机转速的增加先减小后增大,即存在最经济转速,且发动机油门位置越大,对应的最经济转速也越高。为保证动力性能和经济性能,各油门设定的转速应避免设置在最经济转速之下。对于所研究的航空动力装置,在最大连续工况条件下,当飞行速度一定时,动力装置的推力、螺旋桨效率随着飞行高度的增加而降低,单位推力耗油率则随着飞行高度的增加先增加后降低。在飞行高度一定时,动力装置的推力随着飞行速度的增加而降低,而螺旋桨效率、单位推力耗油率则随着飞行速度的增加而上升。

基于多层次客流需求的高铁列车谱系结构优化设计

高速铁路的高质量服务特性激发了大量不同类型旅客的多样化出行需求。当前铁路旅客列车开行数量日益增多,但提供的客运产品分类较少,列车谱系化特征不明显,难以适应旅客的多样性需求。设计具有显性差异特征的铁路客运产品,满足不同类型旅客在经济、快捷、方便、舒适等方面的异质性出行需求,实现铁路客流分类与产品分类的高效匹配,对新时代铁路旅客运输发展具有重要意义。结合当前我国高速铁路网列车开行结构现状,并考虑路网中各线路具有不同的资源、能力、客流特征,基于铁路客运产品谱系化思想和发展趋势,从列车停站模式、旅速、运距、频率几个维度将既有列车种类进一步拓展划分为11类谱系,分析多层次旅客对谱系列车的选择,运用整数规划并结合客流分配技术,构建决策各线路区段上从11类谱系中选择列车开行种类、范围和数量的列车谱系结构优化模型,达到客流类型与列车谱系结构之间的有效匹配。以我国部分高铁路网为例开展案例研究,研究结果表明:优化后的列车开行结构明显改善,各高铁线路上列车谱系结构差异化分布特征明显;不同层次客流旅速、列车谱系和客流层次对应、列车客座率、“车-流”运距比等指标均表现出较好的“车-流”匹配效果。在高铁列车大规模成网运营条件下,研究结果可为设计具有谱系特征的列车产品提供方法和技术指导。

基于改进OMP算法的多目标高速机动检测方法

针对多目标高速机动检测问题,提出了一种基于改进正交匹配追踪(OMP)算法的多目标检测方法。根据高速机动目标运动特性建立信号模型;利用改进OMP算法对脉冲压缩后的回波信号进行运动参数估计;构建相位补偿函数对距离徙动和多普勒徙动进行校正;通过快速傅里叶变换(FFT)完成相参积累,实现对多目标的检测。改进算法适用于多目标高速机动检测场景,可有效避免盲速旁瓣现象及信号交叉项的影响,且具有参数估计精度高和抗噪声能力强等优点。仿真实验验证了改进算法的有效性与可靠性。

气动下压式高速取投苗装置与吊杯时空匹配关系研究

为探索一种能实现高速取苗后无停顿快速投苗、同步接苗技术方案,分析气动下压式高速取投苗装置高速取苗后不停顿快速投苗4个阶段运动过程,得到穴盘苗运动时间。采用高速摄像机对自制高速取投苗装置无停顿快速投苗过程进行拍摄,通过PCC软件进行捕捉分析和计算,分析了穴盘苗在无停顿抛投过程中位移和时间关系。经同步接苗极限分析和交集运算得不同取苗频率吊杯同步接苗提前相位角范围,获得了高速取投苗装置高速取苗、无停顿快速投苗与吊杯同步接苗时空匹配关系。在高速移栽样机上开展吊杯同步接苗试验,试验结果表明,当取苗频率为180株/min时,吊杯同步接苗成功率为96.4%。研究结果为高速取投苗装置与吊杯时空匹配关系提供基础数据。

面向低速运动的稀疏点云实时激光里程计方法

本文提出了一种低速运动情况下使用稀疏点云的实时激光里程计方法。利用局部曲率和主成分分析提取局部网格内的点云面特征,使用点-面距离作为匹配代价函数,在点云位姿估计中利用点云距离和特征平面性对数据重要性进行加权,并针对低速运动对位姿变换矩阵进行近似。在包含大量不稳定特征的场景下,使用16线旋转式机械激光雷达采集的稀疏点云序列进行了试验。结果表明,本文方法对稀疏激光雷达点云具有很好的稳定性,针对低速运动所做近似是有效的,能够大幅提高计算的实时性。

基于目标优化的移不变字典匹配追踪轴承故障诊断算法研究

滚动轴承作为一种关键旋转零部件,在高速列车上得到了广泛的应用。滚动轴承的故障诊断对维护列车的安全、舒适具有重要意义。在故障诊断过程中,实现早期微弱故障的探测以及并发故障的分离和提取至关重要。为此,提出了一种基于蜣螂优化算法的移不变字典匹配追踪算法。该算法采用预定义字典结构和循环提取的思想,首先,引入了蜣螂优化算法,并建立了一种基于相关峭度的新型目标优化函数,以此自适应构建预定义移不变结构的脉冲字典。同时,为了自适应获取匹配追踪框架中的最优稀疏度,提出了基于Hoyer指标的最优稀疏度获取准则。为了验证该算法的优越性,对高速列车传动系统中常见的齿轮箱轴承和轴箱轴承的故障信号进行了分析和对比。结果表明,该算法对早期微弱故障的检测具有更强的鲁棒性,同时对并发故障也具有较好的自适应检测能力,具有一定的工程应用价值。

基于Kano模型的高铁动卧列车女性包房需求研究

为满足新时代女性多层次、个性化出行的需求,改善女性旅客乘坐高铁动卧列车的乘车体验,通过对高铁动卧列车女性包房进行研究,分析设立女性包房后旅客需求的影响因素。首先针对女性旅客旅行需求,从购票方式、旅行时间、车厢环境、服务设施、服务态度、增设项目6个维度设计问卷,通过信度效度检验后,采用Kano模型对旅客需求的属性类别划分为4类;其次利用Better-Worse满意度指数分析法确定用户需求重要度排序,认为女性包房需要满足购票方式、车厢环境、服务设施与增设服务4项需求;最后根据需求分析结果细化为8项具体功能,并在上海至广州的3对动卧列车上进行为期3周的试点,对旅客需求与列车功能的匹配度进行验证。研究结果可为探索高铁动卧列车女性旅客个性化服务提供参考和借鉴。

基于SURF-OKG特征匹配的三维重建技术

为了解决结构光三维重建中传统立体匹配存在的特征点匹配错误、匹配缺失和匹配重复等问题,本文将SURF算法中高斯滤波改进为自适应中值滤波结合小波变换,并提出了一种基于OKG算法的二次特征匹配方法。该算法首先使用自适应中值滤波结合小波变换算法对图像进行平滑和降噪处理,再进行初步特征点提取和匹配,然后将构建的尺度空间划分成多个网格,在每个网格内使用FAST算法提取尺度空间特征点,使用ORB算子提取左右图像的特征点,用BRIEF描述子对其进行描述,采用K-D树最近邻搜索法限制特征点选取,通过GMS算法剔除误匹配点。最后,将本文SURF-OKG算法与传统特征匹配算法进行对比分析,并对阶梯块进行三维重建来验证本文算法的有效性。实验结果表明:SURF-OKG算法的正确匹配率为92.47%;对阶梯宽度为40 mm,精度为0.02 mm的阶梯块进行三维重建,实验测得阶梯宽度的误差均值为1.312 mm,最大误差值不超过1.72 mm,基本满足结构光三维重建系统的实验要求。

工艺参数对高速拉丝应变速率影响研究

现代电缆生产中高速拉丝机上的电线拉丝大大增加了所需的拉丝模具数量,本文给出了拉伸速度对应变速率和塑性变形抗力的影响结果。研究了工艺参数即拉拔速度、模具半角、线材直径和单次应变对金属变形率的影响。研究发现,在选择工艺参数时,以均匀应变原理为指导,通过将单应变与半角模具相匹配,并根据文中给出的公式计算摩擦系数,可以提高拉模阻力,实现快速拉模。