多路况下轮式装载机行驶动力学研究

为了研究多路况下轮式装载机的行驶动力学特性,提出轮式装载机行驶动力学评价方法,建立轮式装载机与路面耦合的动力学模型,仿真模拟得到了轮式装载机在F级对称和非对称路面上空载低速、空载高速、满载低速、满载高速行驶工况下轮心和铲斗处的横向、行驶方向和垂直方向上的加速度值。结果表明：轮式装载机在多路况下垂直方向上的振动是行驶动力学性能最大的影响因素。这种基于ADAMS软件的装载机行驶动力学仿真模拟试验,为轮式装载机行驶动力学的优化与改进提供了一种新颖、有效的方法。     

装载机载质量动态测量偏载问题

在分析已有装载机载质量测量动力学模型基础上,针对偏载的动态补偿问题进行分析.首先对物料偏载状态下的铲斗进行受力分析,给出铲斗水平时偏载的静态计算方法;然后通过动态力矩平衡分析建立起偏载补偿量与转斗液压缸活塞杆行程、铲斗倾角的函数关系式,从而给出当铲斗处于任意倾斜状态时偏载量的动态补偿方法;最后采用自行研制的装载机载质量测量系统分别对物料无偏载、物料存在偏载但不进行补偿,以及物料偏载并进行动态补偿三种情况进行了对比试验.试验结果表明,经过偏载补偿可以获得与理想状况即无偏载时近乎相同的测量结果,即测量误差可以稳定在1%以内,从而验证了理论分析的正确性.     

铲土运输机械

装载机GJ20116080基于ADAMS的轮式装载机耦合减振系统分析[刊,中]/吴兵…//建筑机械.-2010,(10).-65～68针对轮式装载机的液压耦合减振系统,建立了振动模型和数学模型,并分析了液压蓄能器的等效刚度及其影响因素,用ADAMS对某种机型进行了仿真分析。图6表1参4GJ20116081基于有限元的装载机动臂的疲劳分析     

装载机铲斗主刃板焊接工艺的改进

轮式装载机是以装卸散状物料为主的多用途、高效率的工程机械,前后机架、动臂、铲斗是该机的关键结构件。在铲运过程中,铲斗主刃板是受物料磨损的主要部位,磨损严重后不但影响整机的使用性能,而且会减少铲斗容量。因此,如何改进焊接工艺,保证主刃板堆焊层的焊接质量,提高其耐磨性能,具有重要的现实意义。     

基于Pro/E和ADAMS的轮式装载机行驶稳定系统分析

针对为减小轮式装载机物料洒落而加入的液压减振回路的行驶稳定系统,建立其数学振动模型,推导出行驶稳定系统的等效刚度、阻尼并分析其影响因素.为求解数学振动模型的特性参数,采用Pro/E建模和ADAMS仿真方法.分析仿真结果表明:加入液压减振回路可减小行驶稳定系统的振动,而减振效果的关键是选取合适的蓄能器参数.     

装载机铲斗参数优化设计及应用

装载机铲斗性能是确定装载机牵引性能和整体参数的重要因素,为设计出合理的铲斗斗型,实现作业过程的高效节能,需要对铲装作业过程和铲斗尺寸结构进行系统的研究.基于离散元素法,从散体力学的角度对铲装过程进行分析,并通过实验对比验证了模型的正确性.根据四参数铲斗设计原则研究不同截面几何参数的铲斗在相同条件下的插入阻力和满斗率.通过能量法对不同铲斗进行能量分析,得到满斗率尽可能高且最节能的铲斗,最优截面参数为:E0＝40°,D=1.3,E1=52°,G=0.31,为装载机节能型铲斗设计提供可靠地依据.     

对装载机磕斗动作评价参数的探讨

为了清除黏附在装载机铲斗底板上的物料,提高装载机的工作效率和操作者工作的舒适性,福田雷沃公司对装载机磕斗动作的评价参数进行了深入研究并取得了一定成果,现介绍如下。1.装载机磕斗的成因装载机在装卸物料时,     

FL968G装载机工作装置的静力特性分析

装载机已广泛应用于工程领域,但其工作装置在实际的应用中存在开焊与断裂的问题.通过对FL968G装载机工作装置的外载荷与运动的分析,建立轮式装载机的静力模型并借助于有限单元法求解出装载机工作装置的静力特性,发现装载机在偏载且插入铲斗与提升动臂或向后转斗同时进行时,应力与位移最大,确定了动臂的薄弱位置,为装载机的工作装置的改进及优化提供参考依据.     

装载机动臂焊后变形矫正影响因素研究

轮式装载机工作装置中最重要的结构件是动臂,动臂焊接后动臂板开档尺寸对后续焊接在车架孔、铲斗孔及其他销孔位置处圆搭的机加工具有重要影响,同时也对动臂的装配和使用具有重要影响。以动臂焊接变形的矫正过程为研究对象,采用正交实验的方法,对影响矫正过程的影响因素进行辨别、分类和研究。通过对动臂车架孔端和铲斗孔端的尺寸进行正交试验,并对实验数据进行分析,选出符合实际情况、操作性强的最优方案,为研究动臂变形规律和制定矫正工艺路线提供了参考。     

装载机外载荷识别模型的载荷特性

轮式装载机在作业过程中工作装置所受外载荷复杂,目前研究大多基于动力学仿真和理论分析来确定外载荷,所得结果与真实情况有较大差距.以装载机铲斗为研究对象,根据力学平衡方程,推导斗尖外载荷与铲斗铰点力之间的力学关系,建立铲斗外载荷识别理论模型.基于铲斗各铰点处结构特点,设计铰点载荷采集传感器,并结合信号采集仪器,搭建基于铲斗外载荷识别理论模型的载荷测试系统.而后对工作装置进行静态加载实验,发现载荷大小的相对误差在5%以内,角度偏差在3°以内.选取大石方工况进行铲掘实验,对测得载荷进行了不同作业段下的载荷特性分析,发现铲掘段载荷的均幅值最大,均值达到了265kN;重载运输段和卸料段载荷载荷水平接近,其中重载运输段的大载荷比例和载荷频次要高于卸料段;轻载运输段载荷水平最低,其中约90%的载荷均值在50kN以下.该方法可以有效地解决装载机外载荷获取问题,所得载荷特性数据可以为装载机的结构设计和优化提供数据支撑.     

基于弱磁控制的工程机械自适应电子差速控制

传统轮式工程机械使用机械差速器来完成差速,而轮边电力驱动系统的差速功能主要通过电子差速控制技术来实现。分析了常用的电子差速控制策略,提出了基于弱磁控制算法的自适应电子差速技术,搭建了轮边电力驱动装载机模型,并对转弯工况和不同滚动半径直行工况进行了仿真研究,进行了轮边电力驱动装载机的空载转向和重载转向试验。研究表明,采用弱磁控制算法的左右电动轮能够自适应差速,实现平稳转向。     

A comprehensive genetic algorithm for design optimization of Z-bar loader working mechanism

The operation mechanism is generally considered as a key component of a wheel loader. Its working performance has great influence on the service life, stability, efficiency and economy of the loader. This paper establishes a mathematical model of Z-bar loader mechanism in polar coordinate with four-bar linkage and six-bar Watt linkage synthesis, investigates the working performance, such as mechanism transmission ratio, carry stability, parallelism, dumping in any position, bucket flat setting, maximum dig depth, extreme transmission angle and so on. Then we explore new design methods of joint-position of Z-bar loader linkage between tilt cylinder and loader frame to perfect some of the performance. A new method, comprehensive genetic algorithm, is presented to optimize non-linear equation with multi-constraints, and the results improve the multidisciplinary performance. Furthermore, a virtual prototype of the working mechanism is modeled to simulate and verify the optimization results.     

Robust control design for a wheel loader using and feedback linearization based methods

The heavy equipment industry is building more and more equipment with electro-hydraulic control systems. The existing industry practices for the design of control systems in construction machines primarily rely on classical designs coupled with ad-hoc synthesis procedures. Such practices produce desirable results, but lack a systematic procedure to account for invariably present plant uncertainties in the design process as well as coupled dynamics of the multi-input multi-output (MIMO) configuration. In this paper, two H_∞ based robust control designs are presented for an automatic bucket leveling mechanism of a wheel loader. In one case, the controller is designed for the base plant model. In another case, the controller is designed for the plant with a feedback linearization control law applied yielding improved stability robustness. A MIMO nonlinear model for an electro-hydraulically actuated wheel loader linkage is considered. The robustness of the controller designs are validated by using analysis and by simulation using a complete nonlinear model of the wheel loader linkage and hydraulic system.     

An investigation of energy efficiency of a wheel loader with automated manual transmission

This paper describes an investigation of energy efficiency by applying an advanced powertrain system in a conventional wheel loader. A conventional powertrain of a wheel loader consists of an engine, torque converter and transmission. A torque converter in a conventional system generally causes a significant amount of energy loss, as determined by analyzing energy flow based on V-pattern working. To prevent energy loss in a torque converter, Automated manual transmission (AMT) was proposed and modeled in this paper as an advanced powertrain. A wheel loader based on AMT does not need to use a torque converter since the single clutch system is used between the engine and transmission with subsystems of engine controller, clutch actuator and controller. A simplified single clutch system and controller were constructed for V-pattern working of a wheel loader. Additionally, a PI-controller was used as a control algorithm for engine speed control to prevent energy loss while the clutch is not engaged. All simulation models have been constructed in the Matlab/ Simulink environment, and simulation studies were conducted by using a simulation model of a wheel loader with a driver model based on V-pattern working. Simulation results of the AMT-based wheel loader were analyzed by comparison with the results of the torque converter-based wheel loader, and the results show that the AMT-based wheel loader is more energy efficient than the conventional wheel loader.     

基于Matlab的装载机工作装置受力分析

以Matlab为基本工具,分析了装载机工作装置的静力学特性和工作时的受力状态。对偏载工况和对称工况下工作装置的受力情况进行了详细分析和计算,对装载机的动臂和连杆进行了强度校核,并以矿用铲斗式Z30E型装载机工作装置为例进行了受力分析。结果表明:可以通过改变铲斗运动轨迹来减少外力影响。     

港口散货全自动装卸设备的研究与开发

介绍了上海港研发并应用的全自动散货抓斗卸船机、全自动散货装船机和全自动斗轮堆取料机。这些装备集成应用了远距物料轮廓检测、计算机网络、自动控制、智能辅助决策等先进技术,实现港口散货的高效自动装卸及堆场作业、港口散货作业的管理与控制一体化,为建设全自动散货码头奠定了坚实基础。     

多功能装载机工作装置机械-液压系统联合仿真

为准确分析多功能装载机工作装置的运动及各部件的受力状况,研究工作装置在整个工作循环过程中的平移性、自动放平性及其卸料性,应用Denavit-Hartenberg方法来建立工作装置机构运动学模型,并建立液压系统动力学模型。采用多体动力学软件MSC.ADAMS及其液压模块,建立多功能装载机工作装置机械-液压联合仿真模型。对多功能装载机工作装置进行一个循环的仿真分析,研究结果表明,分析结果全面地反映了工作装置的运动状况及各个部件的受力状况,较好地验证了工作装置机械性能和液压系统的动态性能。     

基于Ansys Workbench的装载机铲斗有限元分析

铲斗是装载机重要的工作部件,决定了装载机切削、铲装、运输物料的性能。文中采用AnsysWorkbench软件对某5t装载机铲斗的6种典型_T况进行有限元分析,获得铲斗的结构应力特点和变形情况,以及再要板件的最大应力及其位置,为避免铲斗结构应力集中、优化板件尺寸、强化结构关键部位等提供了有效的基础数据。     

轮式装载机传动系载荷谱编制方法研究

为指导轮式装载机可靠性设计,提出一种轮式装载机传动系载荷谱编制方法。采用"五段法"测试了轮式装载机传动系载荷时间历程信号;通过频谱分析,确定载荷信号频率不超过1Hz的特征;按照"空载运行-铲掘装载-满载运行-卸载"四段的循环特征,对信号进行分割与合并,完成信号的平稳处理;通过雨流计数与工况合成法,获得载荷均值符合正态分布、幅值符合威布尔分布的特征,完成载荷幅值极值的统计推断;根据波动中心法,编制出了轮式装载机传动系各部件的八级载荷谱与程序加载谱。研究表明,轮式装载机传动系载荷信号可依特征分四段平稳处理,且具有显著的概率分布特征,编制的载荷谱符合装载机真实工况。     

Modeling,validation and energy flow analysis of a wheel loader

This paper presents a wheel loader simulation model, validation results and energy flow analysis. The developed simulation model will facilitate the performance evaluation and optimization process in the development stage of a prototype wheel loader. The wheel loader simulation model consists of mechanical and hydraulic powertrain model, multi-body dynamic model and working part dynamic model. The multi-body dynamic model is simplified since the effect of pitch and roll motion of the wheel loader on the energy flow of the powertrain and hydraulic actuator systems is insignificant, a simplified planar model for the dynamic vehicle is good enough for the objective of this study. Every component is modeled and integrated in a simulation package developed using Matlab/Simulink. The simulation model has been validated using experiment data and the validation results show that it effectively represents the actual dynamic characteristic of the target wheel loader. The verified simulation model will be used as a virtual platform to evaluate the performance of alternative powertrain models such as a dual-clutch transmission and hydrostatic transmission. An advanced control system can also be implemented and evaluated using the virtual platform.