具有轮轴伸缩功能的高空作业平台转向机构研究

发布时间：2018-10-29 16:57

【摘要】：自行式高空作业平台是一种运用工作平台通过伸展机构运送工作人员、工具、设备和材料等到指定位置进行工作的特种车辆。自行式高空作业平台的最快时速为6.8km/h,速度低,当工作地点距离较远时,驾驶自行式高空作业平台到达目的地耗时较长,而且禁止在公路上行驶,此时需要借助卡车或运输车,而运输车的运输平台的宽度有限,为了方便自行式高空作业平台的运输,应减少整机宽度。因此在自行式高空作业平台的底盘处增加轮轴伸缩技术(即扩桥技术),该技术能够改变底盘轮距,使得高空作业平台的底盘存在两种轮距状态。当处于运输状态时,使用较窄轮距；当处于工作状态时,使用较宽轮距。由于存在两种轮距状态,导致存在两个转向机构,而每个转向转向机构均存在转向误差,如何同时减少两个转向误差是本文研究的重点。具体内容如下： (1)描述了轮轴伸缩转向机构在自行式高空作业平台底盘中的应用,建立了轮轴伸缩的转向机构转向误差的数学模型,提出双转向误差的概念。 (2)针对带轮距伸缩转向机构的双转向误差问题,建立双转向误差的多目标数学模型,以消除轮胎侧滑为目的,选取相对误差平方的均值为目标函数,以转向机构的底角和腰长为设计变量,建立边界约束条件和性能约束条件,利用多目标遗传算法,借助于MATLAB遗传算法工具箱,解决本文的多目标优化的问题。对于多目标优化后的Pareto解集,本文利用基于变异系数法的解集评价方法,根据决策者的喜好从解集中选出感兴趣的解。以某型号自行式高空作业平台为算例,以多目标优化技术对其进行优化改进,证明了优化方法的可行性和合理性。 (3)运用灰色关联度理论,探讨了结构变量对轮轴伸缩转向机构转向误差的敏感度,找到与转向误差关系密切的结构变量,为后文经验公式选择设计变量提供了参考意见。 (4)利用优化评价后的解,探索轮轴伸缩转向机构的最优布置规律。布置的原则是消除轮胎侧滑,通过优化技术探索底角和腰长与主销距离之间的规律关系。运用最小二乘法数据处理技术,处理评价的优化数据,得到经验公式,为将来设计同类型自行式高空作业平台的转向机构提供了参考依据。
[Abstract]:Self-propelled aerial work platform is a special vehicle which uses the work platform to transport staff, tools, equipment and materials to a designated location. Self-propelled aerial platforms have the fastest speed of 6.8 km2 / h, which is low, takes longer to get to their destination when the workplace is far away, and is not allowed to drive on the road. In order to facilitate the transportation of the self-propelled aerial platform, the width of the whole machine should be reduced. Therefore, in the chassis of the self-propelled aerial platform, the technology of axle expansion (i.e. bridge expansion technology) is added, which can change the chassis wheel spacing and make the chassis of the platform have two kinds of wheel spacing states. Use narrower wheels when in transit and wider wheels when in operation. Due to the existence of two wheel spacing states, there are two steering mechanisms, and each steering mechanism has steering error. How to reduce the two steering errors at the same time is the focus of this paper. The main contents are as follows: (1) the application of wheel-shaft telescopic steering mechanism in the chassis of self-propelled aerial platform is described, the mathematical model of steering error of wheel-shaft telescopic steering mechanism is established, and the concept of double-steering error is proposed. (2) aiming at the problem of double steering error of wheeled telescopic steering mechanism, a multi-objective mathematical model of double steering error is established. In order to eliminate tire sideslip, the mean value of relative error square is chosen as objective function. Taking the bottom angle and waist length of steering mechanism as design variables, the boundary and performance constraints are established, and the multi-objective genetic algorithm is used to solve the problem of multi-objective optimization by means of MATLAB genetic algorithm toolbox. For the Pareto solution set after multi-objective optimization, the solution set evaluation method based on variation coefficient method is used to select the solution of interest from the solution set according to the preference of the decision makers. Taking a self-propelled aerial work platform as an example, the multi-objective optimization technology is used to optimize and improve it, which proves the feasibility and rationality of the optimization method. (3) the sensitivity of structural variables to steering errors of wheel-shaft telescopic steering mechanism is discussed by using the theory of grey correlation degree, and the structural variables closely related to steering errors are found, which provides a reference for the selection of design variables in the empirical formulas. (4) the optimal arrangement of the wheel-shaft telescopic steering mechanism is explored by using the optimized evaluation solution. The principle of layout is to eliminate tire sideslip and to explore the relationship between bottom angle and waist length and the distance of main pin by optimizing technology. Using the data processing technology of the least square method, the optimized data of evaluation is processed, and the empirical formula is obtained, which provides a reference for designing the steering mechanism of the same type of self-propelled aerial work platform in the future.
【学位授予单位】：大连理工大学
【学位级别】：硕士
【学位授予年份】：2012
【分类号】：TH21

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