基于开放平台的嵌入式数控系统研发

发布时间：2018-07-14 22:13

【摘要】：数控折弯机床系统是将控制技术、图元处理技术、折弯技术相结合的智能控制系统。通过读取CAD软件中设计的图元轨迹,然后利用伺服系统对不同材质不同型号的薄壁件进行折弯,加工出所需图样的刀模。这些刀模广泛应用于与其发展相关的印刷包装行业和电子行业中,例如纸箱包装、彩盒、鞋类、手机套等。目前为止,我国数控折弯机床技术经过了数十年的发展,虽然折弯机数控设备具有折弯、打桥位、剪断等功能集于一身,但存在一些共性的问题,比如图元操作不方便、软件操作不稳定,特别是在加工图元复杂时,加工出的工件会有不同程度的误差出现,且误差有一定的随机性,很难建立一个精确的刀模加工数学模型。国产数控折弯机床设备存在低速度、稳定性差、精度不高等缺点,研究如何实时修正刀模高速加工过程中出现的误差,既有学术价值也有应用意义。本文的研究内容主要包括以下几点： 1.研究了薄壁件在加工过程中影响变形的主要因素。首先,基于ANSYS软件的同种材质的不同厚度薄壁件的受力变形的模型建立、载荷施加、非线性求解、仿真。根据各种仿真矢量图和分布云图,很直观的看到应力和位移的分布情况,定性的分析了薄壁件受力变形特性。其次,研究薄壁件在集中载荷作用下弯曲的力学模型。根据满足模型的各种几何边界条件,计算出其挠度函数表达式,确立影响变形的几种主要因素。 2.结合薄壁件自身的弹性特性和折弯过程中的一些主要影响因素,引入T-S模糊控制模型X轴步距、x轴步距变化率、Y轴步距、Y轴步距变化率四个参数。将X轴步距、X轴步距变化率、Y轴步距、Y轴步距变化率四个参数作为T-S模糊逻辑控制器的前提输入变量,将数控插补值的修正量作为模糊控制器的输出参数。针对数控折弯机床系统的特殊性,本文只研究了控制系统中用到的逐点比较法的圆弧插补算法。 3.分析了基于MFC的图元绘制技术以及显示技术,研究了直线拾取算法、圆弧拾取算法、椭圆绘制算法。针对大半径小弧长的圆弧绘制时出现劣弧绘制成其对应的优弧的现象,深入分析了产生此现象的原因,提出了相应的解决方法。设计了图元插补数据结构和图元的矢量图形相关信息、储存的数据结构,使图元的拾取、中点打断、边界打断等功能等能够实现。结合以上研究成果开发的专用数控系统通过数控折弯机床测试并在工业现场应用,表明能够成功解决连续加工多个N型图元时出现的长短脚现象以及两个脚的夹死和张开问题。系统实现了高速、高精度和高稳定性的功能,另外还体现了图元拾取速度快、处理方便等优点,获得客户好评。
[Abstract]:CNC bending machine tool system is an intelligent control system which combines control technology, graphic element processing technology and bending technology. By reading the trace of the drawing element designed in CAD software and using servo system to bend the thin-walled parts of different materials and different types, the cutting die of the needed drawing is obtained. These cutters are widely used in printing and packaging industries and electronics related to their development, such as carton packaging, color boxes, footwear, mobile phone sets and so on. Up to now, the CNC bending machine tool technology in China has been developed for decades. Although the CNC equipment of the bending machine has the functions of bending, bridging, shearing and so on, there are some common problems, such as the inconvenient operation of graphic elements. The software operation is unstable, especially when the processing element is complex, the workpiece will have different degrees of error, and the error has certain randomness, it is difficult to establish a precise mathematical model of cutting die processing. The domestic CNC bending machine equipment has some shortcomings such as low speed, poor stability and low precision. It is of academic value and practical significance to study how to correct the errors in the process of high speed machining of cutter die in real time. The main contents of this paper are as follows: 1. The main factors affecting the deformation of thin-walled parts during machining are studied. Firstly, based on ANSYS software, the deformation model of thin-walled parts with the same thickness is established, the load is applied, the nonlinear solution is solved, and the simulation is carried out. According to all kinds of simulation vector diagram and distribution cloud diagram, the distribution of stress and displacement can be seen intuitively, and the mechanical and deformation characteristics of thin-walled parts are analyzed qualitatively. Secondly, the mechanical model of thin-walled parts bending under concentrated load is studied. According to various geometric boundary conditions satisfying the model, the expression of deflection function is calculated, and several main factors affecting deformation are established. 2. Based on the elastic properties of thin-walled parts and some main factors influencing the bending process, the paper introduces the T-S fuzzy control model and introduces four parameters: the change rate of the x axis step distance and the Y axis step distance change rate of the T-S fuzzy control model. The four parameters of the change rate of the X axis step distance and the Y axis step distance are taken as the input variables of the T-S fuzzy logic controller, and the correction of the numerical control interpolation value is taken as the output parameter of the fuzzy controller. Aiming at the particularity of CNC bending machine tool system, this paper only studies the arc interpolation algorithm of point by point comparison method used in control system. The drawing technology and display technology based on MFC are analyzed, and the algorithms of line picking, arc picking and ellipse rendering are studied. In view of the phenomenon that the inferior arc is drawn into its corresponding superior arc when drawing circular arc with large radius and small arc length, the causes of this phenomenon are analyzed in depth, and the corresponding solutions are put forward. The data structure of element interpolation and the relevant information of vector graph of element are designed, and the stored data structure is designed to realize the functions of picking up the element, interrupting the midpoint and breaking the boundary, etc. The special numerical control system developed in combination with the above research results has been tested by numerical control bending machine and applied in industrial field. It is shown that the phenomenon of long and short feet and the clamping and opening of two feet can be solved successfully when several N-type graph elements are processed continuously. The system realizes the functions of high speed, high precision and high stability.
【学位授予单位】：广东工业大学
【学位级别】：硕士
【学位授予年份】：2012
【分类号】：TP368.1;TG659

【参考文献】