A Conceptual Framework for the Forklift-to-Grid (F2G) Implementation

This paper focuses on presenting the current research findings on the “Vehicle to Grid” concept and proposes theoretical model of F2G integration in energy management of a warehouse. The study is based on an analysis of collected data and on model calculations of the economic value. Analyses of data, calculations of economic value and profitability of the proposed business model give positive results, which fully confirm the thesis that the integration of renewable energy sources and new modern technologies in the logistic processes can improve energy management.

Design of an Electric Forklift

In order to achieve integration of electrmotion and manual operation for manual forklift, this paper designs an improved manual forklift. We select the appropriate motor according to parameters of original manual forklift, which was analyzed by SolidWorks. We make the detailed design of the speed reducer according to the selected motor＇s rated speed and other parameters, and design the reduction speed ratio, reduction speed form, size of gear drive, meshing parameters, force analysis of gear and strength check. In this paper, we electrify the traditional manual forklift eventually.

Control strategy for energy recovery system in hybrid forklift

After analyzing the working condition of the conventional diesel forklift,an energy recovery system in hybrid forklift is considered and its simulation model is built.Then,the control strategy for the proposed energy recovery system is discussed,which is validated and evaluated by simulation.The simulation results show that the proposed control strategy can achieve balance of the power and keep the state of charge(SOC) of ultra capacitor in a reasonable range,and the fuel consumption can be reduced by about 20.8% compared with the conventional diesel forklift.Finally,the feasibility of the simulation results is experimentally verified based on the lifting energy recovery system.

Failure Analysis of Railway Forklifts and Their Current Reliability Levels

The number of forklifts ranks first among the material handling machinery in railway goods yards. It is important to analyze their failures and to assess their reliability. In this paper, the failure distribution, failure modes and laws of failure distribution of railway forklifts are analyzed based on the field data. The comprehensive assessment of the reliability level of the railway forklifts is also presented according to the reliability index system of forklifts.

Accuracy comparison and improvement for state of health estimation of lithium-ion battery based on random partial recharges and feature engineering

State of health(SOH)estimation of e-mobilities operated in real and dynamic conditions is essential and challenging.Most of existing estimations are based on a fixed constant current charging and discharging aging profiles,which overlooked the fact that the charging and discharging profiles are random and not complete in real application.This work investigates the influence of feature engineering on the accuracy of different machine learning(ML)-based SOH estimations acting on different recharging sub-profiles where a realistic battery mission profile is considered.Fifteen features were extracted from the battery partial recharging profiles,considering different factors such as starting voltage values,charge amount,and charging sliding windows.Then,features were selected based on a feature selection pipeline consisting of filtering and supervised ML-based subset selection.Multiple linear regression(MLR),Gaussian process regression(GPR),and support vector regression(SVR)were applied to estimate SOH,and root mean square error(RMSE)was used to evaluate and compare the estimation performance.The results showed that the feature selection pipeline can improve SOH estimation accuracy by 55.05%,2.57%,and 2.82%for MLR,GPR and SVR respectively.It was demonstrated that the estimation based on partial charging profiles with lower starting voltage,large charge,and large sliding window size is more likely to achieve higher accuracy.This work hopes to give some insights into the supervised ML-based feature engineering acting on random partial recharges on SOH estimation performance and tries to fill the gap of effective SOH estimation between theoretical study and real dynamic application.

基于主观生理评价的叉车驾驶舒适性研究

文中通过制订叉车驾驶员工作生理舒适情况调查问卷,对不同吨位叉车驾驶舒适性进行评估。结合工作肌肉骨骼疾患主观评价工具与驾驶室舒适性评价问题,采用滚雪球抽样法进行样本搜集,并运用交叉分析等方法探讨不同吨位叉车驾驶室舒适性影响因素。样本中2.0~3.8 t驾驶室舒适性相对其他吨位最佳,且随着吨位的增加高风险身体部位的患病风险也在增加,4.0~10.0 t座椅可调范围与操作杆的位置适配程度及2.0~3.8 t刹车踏板需要进行改进,1.0~1.8 t和2.0~3.8 t操作杆应选前置,右肩不适与操作杆改进设计相关。该研究为叉车制造商和设计师提供指导,为提高叉车在各行工作场所的安全性和工作质量提供了见解,对叉车人机优化具有一定的工程应用价值。

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%。

基于知识蒸馏的叉车疲劳驾驶检测算法

为解决叉车安全驾驶检测中模型过大、运行缓慢的问题,提出一种基于知识蒸馏的疲劳驾驶检测方法,旨在提升检测性能并减少参数量。文章介绍了YOLO模型和知识蒸馏技术,并定义了分心驾驶的指标,如频繁眨眼、长时间闭眼、打哈欠、拨打电话和吸烟等。通过对这些行为进行标注和对改进后的YOLOv5-S模型进行训练,系统能够实时准确地检测疲劳驾驶迹象。实验结果表明:YOLOv5-L教师模型在测试集上mAP为94.1%,未经蒸馏的YOLOv5-S模型mAP为89.3%,而蒸馏后的YOLOv5-S KD模型mAP提升至92.5%,精度提高3.2%,仅比教师模型低1.6%。该方法适用于资源受限的嵌入式设备和实时应用,为叉车安全驾驶提供了高效可靠的检测方案。

叉车式AGV智能化转运系统在定制化平板纸生产线的应用研究

针对传统平板纸生产线线间转运自动化技术需求,利用多传感器融合技术,设计了龙门货叉平板纸垛姿态调整系统;结合多机器人调度技术,基于OpenTCS架构,开发了叉车式AGV转运系统,实现了多叉车式AGV的协同调度;将所设计系统及方法以一条传统定制化平板纸生产线为案例进行了测试,并分析了系统运行情况。测试结果表明,所设计叉车式AGV智能化转运系统可有效提升定制化平板纸生产线线间转运效率和智能化水平。

混动叉车势能与制动能量联合回收系统设计及AMESim-Simulink仿真分析

针对混动叉车频繁升降及起停制动造成能量损耗严重等问题,聚焦混动叉车势能回收与行车时双动力能源分配控制策略能效提升的关键技术,进行了混动叉车势能与制动能量联合回收系统设计。在传统混动叉车并联式混动系统基础上改进优化,运用前向建模思想搭建仿真模型。为实现精准控制液压缸位移,提出了一种模糊PID自适应控制系统;为优化混动叉车在行车时发动机和驱动电机的工作效率并进行制动能量回收,基于发动机最优工作曲线提出一种制动能量回收控制策略。最后基于JB/T 11988—2014制定多种工况,运用AMESim和Simulink进行多种工况下仿真对比试验,验证该方法有效性,实现能量回收效率提升,势能与制动能量联合回收效率最高可达56.86%。

Tailpipe emission characterizations of diesel-fueled forklifts under real-world operations using a portable emission measurement system

Non-road equipment is one of the key contributing sources to air pollution.Thus,an accurate development of emission inventory from non-road equipment is imperative for air quality management,especially for equipment with a large population such as diesel-fueled forklifts.The objective of this paper is to characterize duty-cycle based emissions from diesel-fueled forklifts using a portable emission measurement system(PEMS).Three dutycycles were defined in this study,including idling,moving,and working(active duty operation)and used to characterize in-use emissions for diesel-fueled forklifts.A total of twelve diesel-fueled forklifts were selected for real-world emission measurements.Results showed that fuel-based emission factors appear to have smaller variability compared to time-based ones.For example,the time-based emission factors for CO,HC,NO,and PM 2.5 for forklifts were estimated to be 16.6-43.9,5.3-15.1,26.2-49.9,5.5-11.1 g/hr with the fuel-based emission factors being 12.1-20.3,4.1-8.3,19.1-32.4,3.5-6.5 g/kg-fuel,respectively.NO emissions appear to be the biggest concern for emissions control.Furthermore,most of the emissions factors estimated from this study are significantly different from those in both National Guideline for Emission Inventory Development for Non-Road Equipment in China and welldeveloped emission factor models such as NONROAD by US EPA.This implies that localized,preferably fuel-based emission factors should be adjusted based on real-world emission measurements in order to develop a representative emission inventory for non-road equipment.

某桁架机械手结构设计与刚度分析

桁架机械手是自动焊接生产线的重要组成部分,为了满足某企业叉车门架自动焊接生产线大跨度、高载重、精度高的要求,设计开发出一款有效行程长为36 m、宽为9.76 m的桁架机械手,其最大载重1.5 t。为了确保其结构性能要求,利用有限元分析工具,验证其最大变形量小于2 mm,结构刚度和强度都满足设计要求;同时桁架机械手制造出来后,经过现场装机测试验证,整体性能指标满足用户需求。

脚手架支承下叉车作用楼面等效均布可变荷载研究

以基坑支护拆撑阶段叉车荷载作用下的楼面作为工况,地下室无梁楼盖结构受到盘扣式脚手架支撑下的等效均布可变荷载的影响较大,且其缺乏有效简单的计算方法,故研究利用ABAQUS大型通用有限元软件对其受力变形进行分析。根据有限元分析模拟探究6 m×6 m无梁楼盖结构受到叉车运输作用下的弯矩、挠度分布情况,提出了可行且简单的计算方法。结果表明,结合规范公式提出的计算方法能较好的得出盘扣式脚手架支撑下的叉车作用楼面等效均布可变荷载,其计算方法可供工程设计参考。

基于ROS架构的叉车型AGV控制系统设计开发研究

针对叉车型AGV开发成本高、系统封闭、可拓展性差的问题,该文基于开源机器人操作系统(ROS),设计了一套新的控制系统。该控制系统采用双层控制架构,通过模块化的设计思想实现了控制平台的搭建。其中,上层控制器采用装有Linux操作系统和ROS的嵌入式工控机实现叉车型AGV的即时定位与建图(SLAM)及路径跟踪功能;下层控制器采用西门子PLC实现对I/O信号的采集,以及通过CAN网络实现对舵轮的行走与转向控制及信息采集、对电源系统实现监控、对货叉起升高度检测,同时可以与车间调度计算机通过无线网络进行AGV调度与在线监控。

基于功率分配的混合动力叉车系统及控制策略研究

叉车作业是物料搬运领域的重要环节。近年来,内燃叉车的排放要求不断升级,为实现节能减排、降低燃油消耗的目标,同时满足多班制连续性作业场景的需求,提出一种基于功率分配的混合动力叉车系统及其控制方案。通过对行走系统采用内燃机与电动机动力耦合的方式,解决了传统内燃叉车在爬坡、重载起升等工况的大扭矩需求,同时避免了在平地运行、小负载起升时因实际有用功需求不多而导致的内燃机无用功的消耗,从而在本质上提高系统的有用功占比,达到节约能源的目的。通过实际应用测试,所提出的混合动力叉车系统的节油率可以达到30%以上。

模块化理念下的物流AGV搬运叉车设计

数字时代的到来与人们生活水平的提升,驱使物流行业迅速朝向自动化发展。文章通过将模块化设计方法应用于物流AGV搬运叉车的设计中,为搬运叉车的设计提供新的研究思路。通过构建搬运叉车作业场景,以及分析物流AGV搬运叉车作业流程,在搬运叉车的模块化设计上进行创新,并对其各项设计要素进行研究,设计出具备更高柔性和适用性的物流AGV搬运叉车。可更换模块、多组成方式、多使用场景的作业模块,能够满足不同物流配送需求,以期为相关模块化搬运叉车的设计提供一定的参考。

基于行为检测的叉车安全监控系统的设计与实现

随着工程应用场景中叉车数量的激增,船舶修造企业叉车伤人安全事故多发频发。视频监控和人工智能技术的日趋成熟为减少叉车安全事故的发生提供了一条新的思路。文章设计并实现了一套基于行为检测的叉车安全监控系统,该系统通过智能可视化的方式对叉车的各种不安全行为进行检测,并对驾驶人员预警提示,从而大大降低船舶修造企业叉车安全事故发生率,同时也为其它工程机械提供了一种可行的参考借鉴方案。

锂电池叉车动力锂电池组散热系统设计与验证

为保障新能源汽车动力锂电池组在电动叉车上的快速推广及可靠应用,研究设计一套极简的叉车动力锂电池组散热系统,解决电动叉车循环高温工况及低压大倍率充放电特性下的动力锂电池组高温问题及循环寿命大幅降低问题变得尤为重要。通过对电动叉车搭载动力锂电池组的热性能仿真分析,对车架结构及动力锂电池组进行了优化设计,保障了动力锂电池组在电动叉车系统中应用的可靠性。通过电动叉车典型工况的模拟试验验证,保障了动力锂电池组在高温环境下运行时,热平衡时的温度能维持在合理的温度区间下工作,避免了电池高温问题以及高温对电池寿命的影响。为电动叉车批量化搭载动力锂电池组进行推广应用提供了有力保障。

面向重载的叉车式AGV货叉结构有限元分析

近年来,随着仓储物流行业的迅速发展,叉车式AGV成为研究人员所关注的重点研究对象之一。面向重载的叉车式AGV的结构稳定性是产品研发关键,本文通过有限元法对其关键件货叉结构进行了静力学和动力学分析。分析结果表明:在满载工况下,货叉结构的强度、刚度和模态分析均满足设计要求,分析结果能在产品设计阶段为避开结构薄弱位置提供一定的参考价值,为货叉结构的开发设计提供参考和依据。

电动叉车起升调速机构设计及可靠性试验方法研究

电动叉车起升功能的基本原理为驾驶人员操作起升阀杆时,阀杆连接着多路阀阀芯,阀杆行程的变化会引起多路阀阀芯运动,从而引起起升阀口的开合度变化。阀口的开合度直接影响液压油流入起升油缸的流量,从而影响起升速度。此外,多路阀上安装有起升调速传感器。阀杆行程的变化会触发起升调速传感器产生连续变化的信号并输出给电机控制器,电机控制器根据接收的信号控制油泵电机转动。油泵电机连接并带动齿轮泵工作,将液压油以不同的流量传递至多路阀起升阀口,并最终传输至起升油缸,从而影响起升的速度。基于此,对起升调速机构的试验方法进行研究,并开展可靠性试验验证,保障起升调速机构的可靠性,促进研究方案的应用。