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.     

Analysis and simulation of a torque assist automated manual transmission

The paper presents the kinematic and dynamic analysis of a power-shift automated manual transmission (AMT) characterised by a wet clutch, called assist clutch (ACL), replacing the fifth gear synchroniser. This torque assist mechanism becomes a torque transfer path during gearshifts, in order to overcome a typical dynamic problem of the AMTs, that is the driving force interruption.The mean power contributions during gearshifts are computed for different engine and ACL interventions, thus allowing to draw considerations useful for developing the control algorithms.The simulation results prove the advantages in terms of gearshift quality and ride comfort of the analysed transmission.     

An experimental investigation of temperatures and energy partition in grinding of cemented carbide with a brazed diamond wheel

An experimental investigation is reported of the temperatures and energy partition in the grinding of cemented carbide with a vacuum brazed diamond wheel. During the experiments, the temperature distributions along the workpiece surface were measured using a sandwiched foil thermocouples and the energy partition to the workpiece estimated using a temperature matching method. The effects of the various grinding conditions, including wheel velocity, feed rate, and depth of cut, on the temperatures and the energy partition were investigated. The measured temperature responses were found to be in good relation with the analytical results of a moving heat source with a triangular distribution at the grinding zone. It was found that the grinding temperatures measured under different grinding conditions varied from 10°C to 100°C. The energy partition to the workpiece in dry grinding was found to be from 35% to 70%. Based on the energy partition values obtained from the experiments, the diamond tip temperature was calculated and found to be over the temperature necessary for the graphitization of diamond if the circular grain contact of radius is smaller than a critical value.     

轮式装载机工作装置的仿真分析

利用三维造型软件UG建立轮式装载机工作装置的六连杆机构,通过多体动力学分析软件ADAMS实现虚拟仿真,通过仿真分析的结果对工作装置机构参数修改以及铰接点位置的重新设定,得出符合设计优化要求的机构参数和铰接点位置,以及油缸运动控制参数。为装载机工作装置的试制提供参考数据。     

蜗轮蜗杆副在机动、手动进给传动机构中的应用

一种新型机动、手动进给传动机构,在传动链起始端都用蜗轮蜗杆副,利用蜗轮蜗杆副反向传动自锁的特点,达到机动进给时自锁手动进给,而手动进给时又自锁机动进给的结果。     

轮式装载机虚拟设计及联合仿真控制研究

基于数字化的虚拟设计技术,利用Pro/E和ADAMS建立装载机零/部件的三维实体模型,通过MECH/Pro接口完成模型的导入与整车的虚拟装配,在ADAMS环境下设定不同的STEP函数,实现装载机典型工况的运动仿真。为进一步优化整车运动仿真过程,利用MATLAB软件编写不同的控制程序,以两侧车轮速度作为输入量,借助ADAMS/Controls模块完成装载机的联合仿真与控制。通过反复修改、调试和控制仿真模型,模拟装载机实际作业的典型工况,大大提高了设计效率,为装载机的深入研究提供了新的设计思路。     

Intelligent energy-saving operation of wheel loader based on identifiable materials

Journal of Mechanical Science and Technology - This study applies image recognition technology to the shovel loading operation of a wheel loader for the first time. In the proposed method, the...     

基于ADAMS的轮式装载机运动学及动力学仿真分析

基于虚拟样机技术,利用ADAMS软件对某轮式装载机建模,并对其进行运动学及动力学仿真,检查装载机在运动工作过程中是否出现干涉,同时获得装载机各部件的运动学及动力学相应曲线,分析装载机结构设计及其受力情况是否合理,为装载机设计提供参考.     

轮式装载机行驶中振动对物料完整性的影响

以轮式装载机为研究对象,对其行驶中铲斗振动对物料完整性的影响进行了研究.首先通过简化分析建立了铲斗振动的数学模型和动态方程,求出其振动响应;然后通过分析铲斗振动的最大加速度,找出了影响物料完整性的各因素;最后基于MATLAB对ZL45型轮式装载机的物料完整性进行了仿真分析.结果表明,绕质心的转动惯量小,且较小弹性系数的低压比宽式专用轮胎等因素,有利于保持物料的完整性.     

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.     

Comprehensive optimum and adaptable design methodology for the working mechanism of a wheel loader

The working mechanism is an important part of a wheel loader. It is used to accomplish the shoveling, loading, lifting, and dumping tasks. Usually, the working mechanism is a Z-bar linkage and the dimensional design of the linkage directly affects the loader’s service performance, such as dumping clearance and dumping height. As there are many other performance indexes and various field requirements for the loader, comprehensive optimum, and adaptable design methodology with full-parameterized kinematic model attracts engineers’ research interests. Focusing on the multi-objective and multi-variable problems, this paper firstly establishes an accurate and simplified kinematic model of the Z-bar linkage with deduced expression of the basic parameters, and then investigates the performance indexes including mechanism transmission ratio, lifting stationary, dumping angle in any position, bucket flat setting, and extreme transmission angle, etc. With the full-parameterized kinematic model and the optimum algorithm, modified complex method, a comprehensive and adaptable design platform is built to solve the multi-objective and multi-variable problems of the Z-bar linkage. A case study with two optimization schemes as “full variables design” and “partial variable design” is conducted. The simulation results show that both schemes are better than the original one. The methodology and platform in this paper are of importance in generating user requirement oriented linkage design schemes with enough consideration and optimization of multiple performance indexes.     

轮式装载机工作装置液压系统分析与改进设计

该文通过对装载机常见的工作装置液压系统原理进行分析,发现翻斗液压缸无杆腔过载会导致活塞杆弯曲、液压软管破裂、油封损坏、无杆转斗拉杆损坏等故障,在此基础上提出改进设计的方法,为同类型的液压回路改进设计提供一定依据。     

装载机动态电子秤采样电路的设计与实现

分析装载机动态称重的实现机理并给出实现方案,通过动态称重系统对硬件设计提出的要求,指出采样电路的合理设计是高精度动态电子秤得以实现的关键.从硬件和软件两方面对采样电路的实现进行分析.最后通过工业现场环境条件下大量的试验,验证所设计采样电路的可靠性和稳定性,动态称重的测量精度稳定在1%以内.     

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。     

小型装载机落物保护装置受落物冲击的动态仿真研究

主要研究了装载机落物保护装置受到落物冲击发生塑性大变形的问题,建立了落物保护装置受瞬态冲击响应的有限元结构动力学方程.以某型号的装载机为例,建立了落物保护装置的非线性有限元模型并讨论了载荷的施加方法和网格的划分,分析了落物保护装置的主要设计参数对顶板中心点最大位移的影响,落物保护装置的动态仿真结果为结构的改进设计提供了依据.并在试验台上对该落物保护装置进行了落锤冲击试验,试验结果和仿真结果吻合得较好.     

Mechanism analysis of pressure fluctuation in wheel loader articulated steering hydraulic system

Journal of Mechanical Science and Technology - This paper studies the influence of hinge point positioning of a steering cylinder on the pressure fluctuation of the steering system of a wheel...     

Force transmission performance for a novel deformation wheel with crank slider mechanism

This study aims to analyze the force transmission characteristics of a novel wheel composed of a mechanism of planar crank slider with virtual constraints.     

Statistical simulation of shift force for a manual transmission

Statistical simulation approaches are proposed to evaluate the shift feeling for a manual transmission. First, shift force simulator for the manual transmission is developed by considering the dynamic models of the external and internal linkage, synchronizer, and drivetrain. It is found that the shift force by the simulator shows a good correlation with the test results. Using the simulator, two kinds of statistical simulation approaches are proposed and the objective parameters that can be used to evaluate the shift feeling quantitatively are obtained. It is expected that the shift force simulator with the statistical approaches, developed in this study can be used asa useful design tool to evaluate the shift feeling in the initial design stage.     

减重涡轮增压器试验研究

以某型号车用增压器涡轮叶轮为研究对象,采用快速成型技术加工了蜡模,浇铸了减重优化的涡轮叶轮,在增压器试验台架上对三台增压器进行了超速破坏试验和整机性能试验,以及转子高速动平衡试验。试验结果表明,减重优化厚度涡轮叶轮满足强度要求,转子的第二阶临界转速降低,但增压器工作转速仍介于二阶和三阶临界转速之间,减重涡轮对增压器效率几乎没有影响。