基于相似理论的高空作业车变幅机构设计研究

发布时间：2018-03-27 09:59

本文选题：高空作业车　切入点：变幅机构　出处：《大连理工大学》2013年硕士论文

【摘要】：高空作业车在各个领域应用需求的急剧增加对产品更新换代的速度提出了挑战。国外企业已具备生产系列化高空作业车产品的能力,其技术先进,安全可靠,能够适应市场需求,然而国内企业产品设计水平较国外企业有较大差距,尤其对于超高型混合臂式高空作业车的设计,多数企业还处于模仿、试制阶段,缺乏新方法和新设计理论的引入。变幅机构是改变高空作业车臂架幅度,使工作平台能够到达指定高度的工作机构,其设计在整机设计中占有重要地位,快速完成变幅机构方案设计可以有效缩短整机方案设计的时间,加快产品更新换代的速度。传统的变幅机构设计方法是将类比法、作图法和解析计算法相结合,但由于高空作业车计算工况复杂使得方案设计阶段计算量较大,采用传统设计方法要得到合理的变幅机构比较耗时费力。课题以百米级混合臂式高空作业车为研究对象,将基于相似理论的设计方法引入到变幅机构设计中,利用已有成熟可靠的产品数据库,快速完成新变幅机构设计。本文对两种典型的变幅机构进行了模型简化并推导了变幅油缸及各铰点的受力公式。研究了各杆件长度及铰点位置的变化对变幅油缸所受最大力的影响。建立了混合臂式高空作业车上部结构的ADAMS模型并对其进行仿真分析,将仿真分析的结果与解析法计算的结果进行对比,验证了解析法推导的受力公式的正确性。在掌握了两种典型变幅机构运动及受力特性的基础上,将基于相似理论的相似优化设计方法运用到变幅机构设计中,,推导了变幅机构的相似准则及各参量的相似比。建立了折叠臂变幅机构和主臂变幅机构相似优化设计数学模型,以变幅油缸所受最大力最小和油压波动值最小为目标函数,相似元中几何尺寸相似比为设计变量,同时考虑相似约束条件和机构性能约束条件,运用遗传算法工具箱进行求解,完成了新变幅机构设计。从动力学相似和运动学相似两方面对变幅机构相似性进行验证,证明相似优化设计方法的可行性。将相似优化模型与缩尺模型进行对比,说明了相似优化设计优于缩尺设计。本文采用的相似优化设计方法,对其它具有相同变幅机构形式的工程机械产品的设计同样具有一定的参考价值。
[Abstract]:The rapid increase in the demand for aerial work vehicles in various fields has challenged the speed of product upgrading. Foreign enterprises already have the ability to produce serialized aerial work vehicles, and their technology is advanced, and they are safe and reliable. Can adapt to the market demand, but the domestic enterprise product design level has the big disparity compared with the foreign enterprise, especially for the design of the ultra-high hybrid arm type aerial vehicle, most enterprises are still in the stage of imitation and trial production. Lack of new methods and the introduction of new design theory. The luffing mechanism is a kind of working mechanism which can change the amplitude of the boom of the aerial working vehicle so that the working platform can reach the specified height, and its design plays an important role in the design of the whole machine. The quick completion of the scheme design of the luffing mechanism can effectively shorten the time of the scheme design of the whole machine and speed up the upgrading of the product. The traditional design method of the luffing mechanism is to combine analogy method, drawing method and analytical calculation method. However, due to the complexity of the calculation conditions of the aerial work vehicle, the calculation amount of the scheme design stage is large, so it takes time and effort to obtain a reasonable amplitude change mechanism by using the traditional design method. The subject takes the 100-meter hybrid arm type aerial work vehicle as the research object. The design method based on the similarity theory is introduced into the design of the luffing mechanism, and the design of the new luffing mechanism is completed quickly by using the existing mature and reliable product database. In this paper, the models of two typical luffing mechanisms are simplified and the force formulas of the variable amplitude oil cylinders and their hinge points are derived. The influence of the length of each member and the position of the hinge points on the variation of the variable amplitude oil cylinders is studied. The ADAMS model of the superstructure of the mixed arm aerial vehicle is presented and simulated. The result of simulation analysis is compared with the result of analytical method, which verifies the correctness of the force formula derived by the analytical method. On the basis of mastering the motion and force characteristics of two typical luffing mechanisms, The similarity optimization design method based on similarity theory is applied to the design of the luffing mechanism, the similarity criterion of the mechanism and the similarity ratio of each parameter are deduced, and the mathematical models of the similarity optimization design of the folding arm luffing mechanism and the main arm luffing mechanism are established. Taking the minimum of the maximum force and the minimum oil pressure fluctuation of the variable amplitude cylinder as the objective function, the geometric dimension similarity ratio in the similarity element as the design variable, and considering the similarity constraint condition and the mechanism performance constraint condition, the genetic algorithm toolbox is used to solve the problem. The similarity of the mechanism is verified from two aspects of dynamic similarity and kinematics similarity, and the feasibility of the similarity optimization design method is proved. The similarity optimization model is compared with the scale model. It is shown that the similarity optimization design is superior to the scale design. The similar optimization design method adopted in this paper also has certain reference value for the design of other construction machinery products with the same amplitude change mechanism.
【学位授予单位】：大连理工大学
【学位级别】：硕士
【学位授予年份】：2013
【分类号】：TH211.6

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