【作者】 佘翊妮；

【导师】 计时鸣；

【作者基本信息】 浙江工业大学 ， 机械电子工程， 2013， 博士

【摘要】 目前,我国挖掘机行业存在的主要问题是：挖掘机品种不齐,缺少大型液压挖掘机,特别是用于矿山开采的大型正铲液压挖掘机几乎没有。为了填补我国大型正铲液压挖掘机的国内空白,某挖掘机生产企业欲研制7-50m3的大型正铲液压挖掘机与国外同类型产品品牌竞争。本文结合与该企业的合作项目,应用虚拟样机技术,进行“基于多体动力学的大型正铲液压挖掘机工作装置动载特性的研究”,包括正铲液压挖掘机工作装置各种工况下运动性能的可视化研究、整个工作范围内斗杆挖掘力的可视化计算、正铲工作装置工作范围、最大斗杆挖掘力和液压系统参数的试验设计与分析及正铲工作装置整体动态强度的研究,旨在解决设计不合理所导致的大型液压挖掘机动臂或斗杆开裂失效、挖掘区域不合理、机体干涉、挖掘力不足、液压系统工作效率低下等问题,为大型液压挖掘机的设计提供理论依据和实用手段。具体研究内容如下：应用D-H法推导正铲工作装置的运动轨迹方程,分析正铲工作装置的主要作业参数和挖掘包络图的绘制方法,然后利用多体动力学软件,建立正铲工作装置的运动学虚拟样机模型,完成正铲工作装置在挖掘、举升、平推工况下运动性能的可视化分析,并绘制出正铲工作装置的挖掘包络图。通过对正铲工作装置运动性能进行可视化仿真分析,可以在没有物理样机的情况下,对设计方案能否满足正铲工作装置工作范围方面的要求进行有效的分析和判断,为企业的设计工作提供参考依据。利用力矩平衡法和空间矢量法建立了正铲挖掘机斗杆挖掘力的理论计算公式。应用牛顿-欧拉法推导正铲工作装置的动力学方程,同时以此为基础建立正铲工作装置机液耦合的虚拟样机模型。通过在铲斗斗尖施加随油缸压力变化的弹簧力的方法仿真计算正铲工作装置的斗杆最大挖掘力,并运用正铲挖掘机斗杆挖掘力的理论公式计算相应工作姿态下的斗杆最大挖掘力,将两者数值进行对比,验证采用铲斗斗尖施加弹簧力模拟计算挖掘力方法的正确性。最后绘制出斗杆挖掘工况下的挖掘力图。利用／ADAMS/Insight的试验设计功能,完成对正铲工作装置工作范围、最大斗杆挖掘力、工作效率的试验设计研究。通过正铲工作装置虚拟样机的多次试验仿真,分析研究多组设计变量同时发生变化对样机性能的影响,优选出使样机性能最佳的设计方案。在ADAMS软件中,建立正铲工作装置的参数化样机模型,运用蒙特卡罗方法研究分析正铲工作装置9个关键铰接点空间位置的变化对正铲工作装置工作范围、最大斗杆挖掘力的影响及举升和斗杆油缸的流量、油管长度和直径等参数对正铲工作装置举升、挖掘时间的影响。从试验结果中优选出工作性能较优对应的设计变量值,并应用层次分析法对工作装置运动性能和挖掘力性能均较优的设计方案进行综合选优。为了更加真实准确的模拟正铲工作装置在工作过程的动态特性,将工作装置的斗杆和动臂视为柔体,建立正铲工作装置刚-柔、机-液耦合的虚拟样机模型。在ADAMS中模拟分析正铲工作装置在自身重力与物料重力作用下,以最大挖掘力挖掘和以高工作效率进行挖掘举升过程中,工作装置各部件的动态应力分布,为更深入研究挖掘机工作装置的力学特性以及动态设计提供理论依据。综上所述,本文对正铲工作装置的运动性能、挖掘性能、工作效率和动态强度进行了深入系统的研究。并对正铲工作装置的运动性、挖掘性能和工作效率进行了试验设计分析。试验结果为该企业的大型液压挖掘机设计提供了有效的技术参考。本研究对推动我国挖掘机行业的科技进步也具有重要的现实意义。更多还原

【Abstract】 At present, one of the main problems in domestic excavator industry is the lack of large hydraulic excavators, especially the lack of large-scale mining shovel hydraulic excavators. In order to improve the quality of our products, a large face-shovel hydraulic excavator with a capacity of7to50m3is being developed by a domestic company to compete with the same type of foreign brand. In this dissertation, based on the cooperative projects with the enterprise and the virtual prototyping technology, a research on the dynamic load characterizes of a large face-shovel hydraulic excavator attachment is developed, including the visualization research on the move performance of the shovel hydraulic excavator under various conditions; the visual calculation of the arm digging force within the all scope of work; the experimental design of the scope of work; the largest stick digging force; the parametric of the hydraulic system and the dynamic strength analysis of the shovel attachment, which can eventually solve the problems arising from unreliable design, such as the crack failure of excavator boom or arm, the unreasonable excavation area, body interference, digging force and low efficiency of the hydraulic system, by providing a theoretical basis and practical means on the design of large hydraulic excavator. The specific contents are as follows:Kinematic trajectory equations of the face-shovel attachment can be derived by D-H method and be used to analyze the major operating parameters and digging envelope diagram. And on this basis, the face-shovel kinematics virtual prototype model is built to undertake a visual analysis of athletic performance of the working device shovel digging, lifting and pushing, and draw the attachment digging envelope diagram. By the visual simulation analysis on the face-shovel attachment, even if there are no physical prototypes, the design can also meet the requirements of the scope of work of the face-shovel attachment, maximum digging force and so on. It is to provide a valuable reference for the enterprise design work.A stick digging force theoretical formula on a face-shovel excavator is established by using the torque balance method and the space vector method. Dynamic equations of the face-shovel attachment can be derived by Newton-Euler method. And on this basis, the mechanism-liquid coupling virtual prototype model is built in ADAMS. Through the spring force which is changed with the pressure of cylinder on the tip of the bucket, the stick force can be simulated. The simulated value of the stick force is compared with the theoretical value to verify the method. Finally the stick digging diagram is drawn under the stick digging condition.Based on ADAMS/Insight, the research of the experiment design about the working range, the maximum stick digging force and the work efficiency of the face-shovel attachment are completed. By repeated experimental simulations on the virtual prototype, the influence on the performance of the attachment are analyzed when a sets of design variables changed at the same time and the best design of the prototype performance can be chosen. By using ADAMS software, the parameters prototype model on the face-shovel attachment is established and the influence of the spatial location change about the attachment’s9key hinge points to the hydraulic face-shovel attachment working scope and the maximum stick digging force is researched. It is also studied that the influence on the flow of the pressure relief valve, tubing length, diameter and other parameters on the face-shovel attachment hydraulic system lifting time during mining and lifting process. From the results, the better design parameters are preferred. And the APH method is used to choose the better design of the hydraulic attachment which has better movement performance and digging performance.In order to simulate the dynamic performance of the face-shovel attachment more realistically and accurately during the process of the work, the attachment’s arm and boom are treated as the flexible body, and the rigid-flexible, mechanism-liquid coupling virtual prototype model is established. During digging and lifting process in high efficiency or in maximum digging force ways, the dynamic stresses of the attachment are analyzed in ADAMS. And the gravity of its components and the material in the bucket are all considered during the analysis process. The results provide a theoretical basis for a further research on the mechanical properties of the excavator attachment as well as dynamic design.In summary, the kinemics performance, the digging performance, the work efficiency, and dynamic stress about the face-shovel attachment are studied thoroughly. The experimental design of movement of the face-shovel attachment, the face-shovel digging performance and the work efficiency has been developed. The results give an effective and technical reference for the large hydraulic excavator enterprises. This study also has important practical significance to promote the scientific and technological progress of China’s excavator industry.更多还原