摘要
套缸式高空作业车,是用于大型激光器的靶室维护设备,属于一种新型的、具有特殊用途的起重机。该设备具有回缩尺寸小、伸缩量、工作幅度大等特点,非常适用于作业空间狭小、尺寸要求严格的工作环境,具有非常强的使用价值。
作为一台独立的机器含有普通高空作业设备的全部功能,同时要适应工作空间狭窄、高洁净等特殊的靶场工作环境,是具有特殊功能的高空作业机械。而设备中运动机构的构型和运动学与动力学特性对设备的性能具有非常重要的影响,为保证设备具有良好的使用性能,设计时有必要对其进行机构综合和动力学分析。
通过对六杆运动链连杆类配方案选择,组合六连杆四种形式,在其基础上再生运动链,形成新的机构形式,完成摆臂机构的型综合。并针对摆臂机构存在启动停止加速度大问题,运用ADAMS对六连杆杆长和固定铰点位置进行尺度综合,实现了参数化设计和运动性能的优化。
运用平面机构动力学建模的等效元素集成法建立了摆臂机构的等效动力学模型,把等效的思想和有限元的方法结合起来,采用有限元方法对单元进行集成组装,给出了二阶及三阶转换张量的列写方式及系统质量阵的组装形式,推导出了系统的动力学微分方程,避免了用传统方法列写动力学方程时由于人为技术原因容易出错的缺陷。
在起重机出现的事故分析当中,起重机的稳定性失效是一个非常重要原因。本文通过考虑臂间搭接产生摩擦,推导出箱形伸缩臂稳定性方程,定性并定量地分析变截面梯形柱、考虑油缸和计及摩擦影响时吊臂整体失稳欧拉临界力的差异。
对伸缩机构进行了模态分析,基于Ansys平台对其结构进行了模态提取,得到整机的前十五阶模态,并分析了振型的特点以及部分起振的原因,为结构的优化设计提供了理论依据。
The cylinder-type aerial work platform studied in this paper, which is used for the maintenance of the target chamber in large lasers, is a new crane for special purpose. This platform has the characteristics of small retraction size, big expansion range, working range and so on, and is applicable to the working conditions with narrow working space and strict size requirement, so it has strong use value.
As an independent machine, this platform can realize all the functions of ordinary aerial work platform, and can simultaneously adapt to the special working environment with narrow working space and high cleanness, it's an aerial work platform with special functions. The configurations, kinematics and dynamics of motion mechanisms in the platform are the important influence factors of the performance of the platform. To ensure the platform has a good service performance, it's necessary to do mechanism synthesis and dynamic analysis while designing the platform.
Four forms of six bar mechanism are combined through selecting the classification and distribution schemes of six-bar kinematic chain connecting rod. On this base, a new mechanism form is formed by regenerating kinematic chains, and the type synthesis of the swing arm mechanism is completed. Aiming at solving the problem that the swing arm mechanism has a great acceleration when starting and stopping, dimension synthesis is done with the rod length of six connecting rods and the position of hinge joints by using ADAMS, therefore the parametric design is realized, and the motion performance is optimized.
An equivalent kinematic model of the swing arm mechanism was built up based on equivalent element integration method of planar mechanism kinematic modeling. Combining with the equivalent thought and finite element method, elements are integrated and assembled by adopting finite element method. The listing method of the second-order and third-order conversion tensor and the assembled form of the system mass matrix are presented, and the system kinematic differential equations are deduced, therefore avoiding man-made mistake in listing kinematic equations by using traditional method.
The cranes'stability failure is a very important aspect in the accidental analysis of cranes. In this paper, the stability equations of box-type telescopic boom are deduced according to the friction between the joined arms. The difference of the whole instability euler critical force of boom is qualitatively and quantitatively analyzed, for which a variable cross-section trapezoid column, and the influence of cylinder and friction are taken into account respectively.
Modular analysis is done to the telescopic mechanism, and modal extraction is done to the structure based on Ansys platform, and the previous fifteen-order modals of the whole machine are obtained. In addition, the character of mode shape and cause of sectional vibration are analyzed to provide a theoretical basis for the structural design and optimization.
引文
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