【作者】 赵连玉；

【导师】 高峰；

【作者基本信息】 河北工业大学 ， 机械制造及其自动化， 2008， 博士

【摘要】 本文对轴类零件塑变校直技术的基础理论、基本方法和自动化校直加工技术进行了较为深入的研究和探讨。采用非线性有限元方法对目前工程上广泛应用的3点弯曲法校直的工艺过程和机理进行了分析与计算,计算结果表明,通过施加合理大小的载荷和载荷作用方式,一次加载即可得到较高的校直精度。同时得出结论:施载机构的作用节点数须选择适当,节点过多时会产生明显的弹性核,节点过少时又会形成局部塑性铰。在充分分析和借鉴国内外现有自动校直机研究和技术现状的基础上,提出一种全新的低成本四导柱卧式自动校直机结构模型,并设计制作了原理样机。该样机在工件较长时只需相应增加导柱的长度,因此可改变自动校直机一般只能对中小型工件进行自动化校直加工的技术现状。样机结构简单、加工容易、易于保证精度。而目前国内外普遍采用的门式或C型结构自动校直机受工作台面长度的限制,只能校直中小型轴类零件。针对模型样机的具体结构建立了工件轴线和导柱挠曲变形的误差模型,分析并说明了模型样机对工件弯曲变形的检测原理及校直施载机构的行程控制与误差补偿方法,基于需求分析与人机工程学的原理研制了模型样机的自动控制系统,包括硬件平台的建立和全部工作软件的开发。实现了工件测量和校直加工的自动化。控制系统的软、硬件体系结构可完全移植到产品样机中。本文还重点探讨了校直加工过程中的智能控制方法。在总结人工操作经验的基础上,设计了以需校直工件的塑性变形量及其变化量作为输入,以加载行程为输出的具有自学习功能的二维模糊控制器,提高了校直加工的效率和精度。在定义了数据结构和变量数组的基础上,给出了参数自学习过程算法,改善了模型样机对不同规格样本工件的适应性。在模型样机上进行了大量的校直加工实验,实验结果验证了本文提出的全自动校直加工方法及控制算法的有效性。实验数据表明,对于多数工件,一般只需要3到5次加载即可达到较高的校直精度。样机工作稳定、可靠,具备了从模型样机到产品样机的转化条件。更多还原

【Abstract】 In this paper, the basic theory and method about plastic deformation straightening technology of shafts together with the automatic straightening processing technology are studied and discussed.A method for straightening named variable constraint three points bending is proposed, and the technological process and the straightening mechanism based on the method proposed are analyzed and calculated by nonlinear finite element method. The results of calculation show that higher precision can be gained through once loading while the magnitude and the application mode of loading are reasonable. Meanwhile, a conclusion also can be reached that the number of application nodes must be chosen properly, if not, obvious elastic region can occur when there are too many nodes, and local plasticity can appear while there are few nodes.The structural model of a new low cost horizontal automatic straightener with four pillars is proposed in the basis of analyzing and referencing existing research and technology about automatic straightener, and a principle prototype with simple structure, handling ease and easy guaranteed precision is deigned and fabricated. The prototype can straighten longer parts through lengthening pillars, changing the state of automatic straightener only suitable to straighten micromidi parts. Whereas, the existing automatic straightener which is gate type or C type can only straighten micromidi shafts in restraint of the length of work top.An error model about axial line of parts and flexural deflection of pillar is established according to concrete structure of the prototype, and the detecting principle of flexural deflection, motion control of loading mechanism and error compensation process are analyzed. Moreover, the automatic control system of the prototype is developed including hardware platform and all software based on demand analysis and ergonomical principle. So the automation of parts measurement and straightening process are realized. The hardware and software of the control system can be implanted in products.Intelligent control method in straightening process is also researched,a two-dimensional fuzzy controller with self-learning function is designed to promote efficiency and precision of straightening process. Inputs of the controller are amount of plastic deformation and its variance, and output is loading course. A parameter self-learning algorithm is presented after defining data structure and variable array to improve the prototype’s adaptability to different size of workpieces.At last, lots of straightening processing experiments are done on the prototype, and experimental results proof effectiveness of the processing method and the control algorithm proposed in the paper. Experiment data show that the higher straightening precision can be reached by three to five loading for most of workpieces. However, the prototype is stable and reliable so that products can be fabricated based on the prototype.更多还原