【作者】 裴磊；

【导师】 邱清盈；

【作者基本信息】 浙江大学 ， 机械设计及理论， 2008， 硕士

【摘要】 随着社会的发展,挖掘机的数量大幅增长,其所消耗的资源、排放的污染物以及在施工中产生的噪声、粉尘对能源和环境产生了难以估计的负荷。因此,国内外各挖掘机生产厂家和研究机构在挖掘机的节能方面进行了不同程度的研究。节能的研究主要有两个方面:提高能量利用率和能量回收。前者可以通过电液比例控制智能化、柴油机电喷控制、负荷传感控制、泵的多功能组合和提升泵与发动机的智能化匹配程度等技术来实现,而这些技术中的许多已经相当的成熟,要想进一步提升会有不小的难度;后者在混合动力技术的大力发展及能量回收系统成功应用于汽车上,并较大幅度提高了其能量二次利用率的背景下,已经引起了世界上很多大的工程机械公司和研究机构的兴趣,其在挖掘机上的应用必将对节能幅度的提升产生不小的影响。本文以5吨级液压挖掘机为对象,针对目前挖掘机上存在的动臂、斗杆和铲斗下降后因势能无法回收而造成的能量损失以及由此而引起的液压元器件发热、失效加速磨损等问题,基于混合动力提出了一种由液压缸、节流阀、变量马达和发电机组成的挖掘机势能回收系统,并利用MATLAB软件中的Simulink建立了该系统的仿真模型,分析了各定量、变量参数和系统响应频率之间的关系,重点研究了各变量参数对系统的能量回收效率、能量回收速度、以及挖掘机工作效率的影响,并根据仿真结果及实际情况提出了对各个变量参数的一套控制方案,使该系统的回收效率尽可能地达到最大。论文主要分为以下几个部分:1、分析了液压挖掘机节能的重要意义,介绍了挖掘机上工作元件、液压系统和发动机—泵功率匹配等节能控制技术的发展情况,以及国内外各公司混合动力发展与应用和现有能量回收系统的原理与应用,同时提出了本文课题,说明了设计适合混合动力挖掘机的能量回收系统的必要性和可行性,并概述了本课题的研究内容和论文所进行的研究工作。2、利用D-H方法给混合动力挖掘机工作装置的动臂、斗杆和铲斗分别建立了各自的坐标系,并以此和他们之间的换算关系建立了该机构的运动学模型,最后利用拉格朗日方法推导出了其动力学理论模型。3、根据混合动力挖掘机自身的特点,设计出了完整的势能回收系统,并对该系统中液压部分的各个元件进行建模,以及这些模型之间的整合,推导出系统的传递函数,和系统的液压固有频率,根据分析出的变量及定量参数对该频率的影响,针对性地提出了几条提高系统响应速度的方法。4、根据第二章建立的动力学模型,仿真出各个液压缸所受的负载,并定性地判断出在工作装置下降后,每个液压缸所能获得的液压能的大小,略去较小部分,对大的进行回收。同时分析了各个参数对系统总能量回收效率的影响,并通过对仿真中回收情况的观察提出对参数的控制方法,使系统的回收效率尽可能地达到最大。5、概括了论文的主要研究工作和成果,并展望了今后的研究工作和方向。更多还原

【Abstract】 With the development of society, the number of excavators has increased quickly. In the course of construct, all the resource consumed, the pollutant released and the noise made by excavators has made a incalculable load to environment and energy, so many excavator manufactures and institutes at home and abroad have taken much research in energy saving. Energy saving includes two sides: increasing energy usage and energy recovery. The former could be realized by technologies such as electro-hydraulic proportional control, EFI diesel engine control, load-sensing control, intelligent matching between pump and engine, etc. And much of these technologies are mature, so it will be hard to improve further. In the background of development of hybrid technology, the last has been used in cars, and improves energy’s secondary application, so it attracts a lot of world’s largest companies and institute’s interest. If the energy regeneration system is used on excavator, it must be helpful for energy saving.To solve the problems such as heating, inactivation, and wearing caused by energy loss when the arm, the boom, and the bucket fall down, based on hybrid technology, this paper proposes an energy regeneration system made up of fluid cylinder, throttle valve, variable displacement motor and engine. In this paper the author builds the model of the system, analysis the relationship between quantitative parameters, variable parameters and system’s response frequency, researches on the variable parameters to the impact of efficiency and velocity of energy regeneration system, and work efficiency of the excavator. According to the simulation result and actual situation, a control method to variable parameters is proposed to reach the best result as far as possible.This paper includes several parts as follows:1 This part introduces the mean of energy saving in excavator, the development of control technology in energy saving such as improving the performance of hydraulic components and power matching between energy and pump, the development and application of hybrid system, the application of present energy regeneration system. As the same time, the topic of the paper is raised. The necessity and feasibility of designing a suitable energy regeneration system for hybrid excavator are showed. The content and the research about the topic are overviewed.2 Coordinate systems for arm, boom and bucket in hybrid excavator are founded by using D-H Method. From these coordinate systems a kinematics model is built, and in the end a dynamical model is deduced by Formula Lagrange.3 According to the characteristics of hybrid excavator, a complete potential energy regeneration system is designed. The models of the hydraulic parts are built, and after integrating the models, the transfer function and hydraulic natural frequency of the energy regeneration system are obtained. Several methods for increasing response speed are proposed through analyzing the influence to the frequency by changing variable and fixed parameters.4 According to the dynamic model that built in chapter 2, the load of fluid cylinder is simulated, and through qualitative analysis to the energy that fluid cylinder gets, the smaller part is ignored. In the course of simulation, the influence to the total efficiency of the system by every parameter is analyzed. From this analysis some control methods to the parameters are pulled out to reach the best result as far as possible.5 All the research and results are included, and the direction of the research next is showed.更多还原