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考虑大变形因素的高空作业车倾覆稳定性研究
Overturning Stability Analysis of Aerial Work Platform Based on Large Deflection
【作者】 刘东;
【导师】 赵福令;
【作者基本信息】 大连理工大学 , 机械电子工程, 2011, 硕士
【摘要】 高空作业车在市政、风电、机场、消防等上有广泛的应用和极其重要的用途。近年来,引起了研究者的特别关注,特别是作业高度超百米高空作业车。作业高度超百米高空作业车整机倾覆稳定性问题是保证其基本性能的安全要求关键内容,整机倾覆稳定性的稳定与否直接影响高空作业车基本性能及其倾覆事故发生。但是针对作业高度超百米高空作业车倾覆稳定性研究还比较少见,并且国内目前尚未见较成熟的设计分析理论依据。因此,本文以作业高度超百米高空作业车为研究对象,运用空间梁单元几何非线性有限元法分析其臂架的大变形,在此基础上引入零力矩点(Zero Moment Point, ZMP)动态稳定性判别方法,对高空作业车整机倾覆稳定性问题进行系统深入研究。目前设计中使用的臂架变形分析方法没有考虑臂架扭转、变幅与回转平面内的耦合作用等问题。因此,对高空作业车臂架的大变形分析精度不高并且设计分析方法不够完善。本文首先假设空间梁单元的几何关系;然后论述和推导具有初始挠度的空间梁单元力学模型(切线刚度矩阵、单元坐标转换矩阵与单元杆端抗力)与采用牛顿法的空间梁系结构几何非线性有限元计算流程;最后利用MATLAB语言编制了空间梁系结构几何非线性有限元程序,实现了综合考虑上述因素影响下的作业高度超百米高空作业车臂架的大变形计算。通过算例分析比较,验证了本文梁单元力学分析模型的实用性和程序的可行性。本文将ZMP法稳定性判别方法引入到作业高度超百米高空作业车的倾覆稳定性研究中,首先介绍了高空作业车倾覆稳定性假设条件;然后推导了基于ZMP法高空作业车整机动态ZMP点坐标值与稳定裕度计算方法;最后利用臂架大变形计算结果修正臂架位姿,在臂架新的位姿下,论述了基于ZMP法高空作业车整机倾覆稳定性的计算方法,从而实现了考虑大变形因素的整机倾覆稳定性的算法研究。本文研究成果对高空作业车抗倾覆稳定性校核设计提供重要理论参考,并对伸缩式臂架系统设计与结构刚度分析具有重要的参考价值。并且该研究成果应用到我校工程机械研究中心和中联重科专车有限公司合作实际项目——GHK111米大臂架高空作业车产品设计开发中,对其设计提供了理论上的参考。
【Abstract】 For its extensive applications in services, wind power, airport and fire, aerial work platform (AWP) has captured special attention of many researchers in recent years, working height over one hundred meters especially. Overturning stability analysis of working height over one hundred meters AWP is the key component of its safety requirements of basic performance. And the overturning stability characteristics of AWP affect directly the basic performance and overturning accidents occurred. However, overturning stability analysis of working height over one hundred meters AWP is still relatively rare, and there is not yet mature design and analysis theory. Therefore, the working height over one hundred meters AWP was taken as the research object, and the theory of the geometric nonlinearities 3D beam element and the algorithm of finite element method are applied in the research of the nonlinear large deflection of AWP boom, and the Zero Moment Point (ZMP) dynamic stability determination method was introduced, systemic research has done at the overturning stability analysis of AWP based on large deflection in this paper.The current deflection analysis of boom doesn’t take into account of torsion of boom, coupling effect of range plane and revolution plane, and the nonlinear factor. Therefore, accuracy of analysis is not high. In this paper, the geometry of 3D beam element was assumed, then the 3D beam element mechanical model, which had the initial deflection, and the 3D beam element geometric nonlinear finite element method calculation process was discussed. The incremental Newton-Rapson method was adopted. The mechanical model includes element tangent stiffness matrix in elemental coordinate system, element coordinate transformation matrix, and the element rod end resistance. Finally, the 3D beam element geometric nonlinear finite element program was developed, which was structured based on MATLAB language, and which can analyzed the large deflection of AWP boom. Two numerical examples are analyzed. The numerical result illustrates the beam analytical model and analytical methods presented in this paper are accurate and effect.ZMP method was introduced to analyze the overturning stability of working height over one hundred meters AWP. First, the working height over one hundred meters AWP the overturning stability assumptions was introduced. Then, the expression of the ZMP point coordinate based on ZMP method was given. The value of the dynamic stability margin was derived. Finally, the method of overturning stability analysis of working height over one hundred meters AWP was discussed, which based on boom new pose by the results of boom large deflection. The ZMP dynamic stability determination method was adopted. The method and algorithm for solution the overturning stability problem of AWP based on large deflection is obtained.The results in this paper provide an important theoretical basis for optimization, analysis and the design of the overturning stability analysis and the boom of working height over one hundred meters AWP, and have been used in the product design and development of GHK111 meters large boom AWP, which was the actual project cooperation by our school construction machinery research centers and Zoomlion Ltd.
【Key words】 Aerial Work Platform; Overturning Stability; Large Deflection; Geometric Nonlinearities; Beam Element;