反铲液压挖掘机挖掘性能实验及理论研究

发布时间：2018-04-18 17:53

本文选题：液压挖掘机 + 挖掘力　；参考：《重庆大学》2014年博士论文

【摘要】：作为典型的机电液一体化产品，挖掘性能是挖掘机的核心性能指标，对挖掘性能的研究是实现机械、液压和控制系统性能匹配的前提，更是实现液压挖掘机节能、高效和智能化的基础。国内外众多学者针对挖掘性能的研究取得了很多成果，也存在一些不足。这些不足主要体现在以下方面：①现有方法并不能解决实际挖掘过程中挖掘阻力的准确求解问题；②强度分析结果与实际失效形式不符，缺乏对工作装置动静态强度分析的有效方法；③现有理论挖掘力模型无法得到挖掘机在极限挖掘工况下所能发挥的最大挖掘力，也不能针对复合挖掘工况的挖掘能力进行有效评估；④现有图谱分析法不能对挖掘性能作出准确的评价。为解决这些问题，本文主要针对实际挖掘过程中挖掘阻力模型、应力和挖掘阻力测试平台、动静强度分析和验证方法、理论挖掘力建模和挖掘性能分析方法等方面进行了理论与实验研究。本文的具体工作和研究成果主要包括以下内容： 1)基于平面力系原理，提出一种将挖掘阻力系向切削刃合成为切向阻力、法向阻力和阻力矩的方法，使挖掘阻力的准确求解成为可能。建立液压挖掘机运动学和动力学模型，结合挖掘阻力系合成结果，提出实际作业过程中挖掘阻力准确求解的测试计算方法，突破了利用经验公式和模拟方法预测挖掘阻力大小的现状，使斗形装置实际作业中挖掘阻力特性分析成为可能，为挖掘性能相关研究奠定理论基础。 2)建立液压挖掘机工作装置姿态、应变和油压的同步采集测试平台，并完成多次挖掘过程中多种数据的采集、转换和拟合。利用测试数据和挖掘阻力模型，计算各种挖掘工况对应的挖掘阻力，根据应力应变关系计算所有测点在挖掘过程中的当量应力，为挖掘阻力特性研究和应力结果对比提供实验依据。 3)对比实际挖掘过程的动应力峰值与相同挖掘姿态下的静应力仿真值，分析静强度计算结果与真实动应力之间的关系，研究液压挖掘机工作装置广义动载系数的范围，提供一种利用静强度分析手段解决动载荷问题的方法。 4)利用实验测试数据，基于达朗贝尔形式的挖掘阻力模型，计算出动臂和斗杆各个铰点在实际挖掘过程中的载荷谱。将其作为外载，，利用瞬态分析方法仿真动臂和斗杆整体动应力分布规律。对比动应力的测试与仿真结果，不但验证了瞬态分析过程的正确性，找到一种动强度分析的可行方法，也验证了挖掘阻力模型的正确性。 5)利用实际挖掘过程中挖掘阻力的测试计算结果，从总体特性、力值大小和方向特性3个方面分析挖掘阻力各个部分的变化规律，基于统计学原理研究阻力系数、阻力矩系数、阻力角、差值角的主值区间和概率密度。研究斗形装置在真实作业过程中的挖掘特性和挖掘阻力变化规律，为工作装置的设计、优化和理论挖掘力模型的建立提供实验依据。 6)基于挖掘阻力的总体特性和力值大小特性提出极限挖掘力的概念和计算模型，解决了现有理论挖掘力模型无法计算出挖掘机本身在单独挖掘工况下所能发挥的极限挖掘力问题；基于复合挖掘过程中挖掘阻力的方向特性，提出并建立了复合挖掘力的概念和模型，为复合挖掘过程挖掘能力的评价提供一种方法，突破现有理论，奠定了液压挖掘机挖掘性能准确评价的理论基础。 7)突破以挖掘姿态为研究对象的传统方法限制，提出基于工作域的图谱分析法。该方法从根本上避免了因一个挖掘点对应多种挖掘姿态而带来的问题。以挖掘阻力的测试计算结果为基准，对比基于工作域的图谱分析法与传统方法，结果表明：基于工作域的图谱分析法能够更为准确的反映所在挖掘点的挖掘能力，基于此得到的挖掘力图和挖掘限制图揭示了挖掘力及其限制因素的区域性分布规律，能够准确展现液压挖掘机的挖掘性能。利用基于工作域的图谱分析法研究了4种吨位相近的中型反铲液压挖掘机的挖掘性能，分析过程显示该方法不仅可以提供较为直观的理论挖掘力及其限制因素分布图，还可以提供挖掘力和限制因素比例的统计结果，为液压挖掘机挖掘性能的分析和评价提供了理论依据，为实际的工程应用提供了可靠的方法。
[Abstract]:As a typical integrated product of electro - mechanical fluids , the mining performance is the core performance index of the excavator , and the research on the excavation performance is the premise of realizing the performance matching of the mechanical , hydraulic and control systems , and it is the foundation of energy saving , high efficiency and intelligence of the hydraulic excavator .
( 2 ) The results of strength analysis do not accord with the actual failure modes , and there is a lack of effective methods to analyze the dynamic static strength of the working device ;
( 3 ) the existing theory mining force model can not obtain the maximum digging force which can be exerted by the excavator under the limit digging condition , and can not effectively evaluate the digging capacity of the composite excavation working condition ;
In order to solve these problems , this paper mainly focuses on the theory and experimental research on excavating resistance model , stress and excavation resistance test platform , dynamic and static strength analysis and verification method , theoretical digging force modeling and mining performance analysis method in actual excavation process . The concrete work and research results of this paper mainly include the following :

1 ) Based on the principle of plane force system , a method of combining excavation resistance to cutting edge into tangential resistance , normal resistance and resistance moment is proposed to make the accurate solution of excavation resistance possible .

2 ) establishing a synchronous acquisition test platform of the attitude , the strain and the oil pressure of the working device of the hydraulic excavator , and completing the collection , conversion and fitting of various data during the plurality of excavation processes .

3 ) comparing the dynamic stress peak value of the actual excavation process with the static stress simulation value under the same excavation posture , analyzing the relation between the static strength calculation result and the real dynamic stress , researching the range of the generalized dynamic load coefficient of the working device of the hydraulic excavator , and providing a method for solving the dynamic load problem by using the static strength analysis means .

4 ) Using the experimental test data , the load spectrum of each hinge point of the boom and bucket rod is calculated on the basis of the excavation resistance model in the form of the Dalang Bell . As an external load , the dynamic stress distribution law of the movable arm and the bucket rod is simulated by the transient analysis method . The test and simulation results of the contrast dynamic stress are verified , and the correctness of the transient analysis process is verified , and the feasible method for analyzing the dynamic strength is found , and the correctness of the excavation resistance model is also verified .

5 ) Based on the statistical principle , the rule of resistance coefficient , drag torque coefficient , drag angle , main value interval and probability density of resistance coefficient , drag coefficient , drag angle and difference angle are analyzed from three aspects of overall characteristic , force value size and directional characteristic .

6 ) the concept and the calculation model of the limit digging force are put forward based on the overall characteristic and the force value size characteristic of the excavation resistance , and the problem that an excavator can not be calculated can be calculated by the existing theory digging force model can not be calculated ;
Based on the directional characteristic of excavation resistance in the process of compound excavation , the concept and model of compound digging force are proposed and established , which provides a method for the evaluation of the excavation capacity of the composite excavation process .

In this paper , the mining performance of the hydraulic excavator can be accurately reflected by using the map analysis method based on the working domain . The results show that the method not only can provide more visual theoretical digging force and its limiting factor distribution map , but also can provide the statistical results of the mining force and the limiting factor ratio , and provide theoretical basis for the analysis and evaluation of the excavation performance of the hydraulic excavator .

【学位授予单位】：重庆大学
【学位级别】：博士
【学位授予年份】：2014
【分类号】：TU621

【参考文献】