【作者】 士贺永；

【导师】 董长双；

【作者基本信息】 太原理工大学 ， 机械制造及其自动化， 2010， 硕士

【摘要】 随着各种先进制造技术的普及应用,新材料新工艺的发展,凸轮的设计与制造将会变得十分方便和精确,制造成本也会大幅下降,尤其是随着计算机的发展,凸轮机构的计算机辅助设计和制造已获得普遍地应用,从而提高了凸轮设计和加工的速度及质量,这也为凸轮机构的更广泛应用创造了条件,更好地促进自动机械的发展。通过分析凸轮轮廓曲线的特征,本文提出了极坐标数控的凸轮加工方案,即通过控制旋转运动和直线运动,实现在极坐标下,对凸轮的数控加工。在极坐标下,利用极角与极径的关系,更容易设计理想的凸轮轮廓曲线,此方案避免了凸轮曲线方程从极坐标向直角坐标的转化,控制一旋转运动与一直线运动,插补出凸轮轮廓曲线。插补的算法采用数据采样插补,即在一个插补周期内,判断各轴的运动方向,计算出各轴的运动增量。另外还对插补误差进行了研究,并给出了插补误差控制方法,使其每一步插补均能满足精度要求。本课题的控制系统设计,采用上位机(PC机)与下位机(PLC)相结合的方式。利用PC机强大的软硬件功能,实现对凸轮轮廓曲线的插补算法计算,求出满足精度要求的节点坐标、插补步长,并把这些信息传送给PLC,由PLC驱动伺服电机插补运动,完成加工。由于加工过程中,需要联动控制,因此,选择FM357作为定位模块,最多能同时控制四轴运动,满足控制系统的要求。最后,本文根据凸轮轮廓曲线常用的运动规律,对各种运动规律的方程进行适当的修正,使其能根据设计的需要平滑过渡,并编写了凸轮轮廓曲线生成程序,利用MATLAB的绘图功能,生成所设计的凸轮轮廓曲线模型。有了凸轮轮廓曲线的数学模型,再利用MATLAB算法开发与强大的数学计算能力,即可进行凸轮轮廓曲线的插补算法仿真。通过编写插补程序,实时的插补误差控制,并利用MATLAB实时绘图功能,实现了凸轮轮廓曲线的动态仿真,证实了算法的可行性,最后对插补结果进行分析,验证了算法的正确性。另外,选用VB进行PC机应用软件的开发,编制了插补仿真界面,编写了VB与MATLAB接口程序,以及VB与PLC通信的程序。更多还原

【Abstract】 With the development of new materials and new process, all kinds of advanced manufacture technology have been applied widely, so cam design and manufacture will be verily convenient and precise, and cam production cost will also be reduced. Especially, with the development of computer, Computer-Aided design and Computer-aided Manufacture are applied to cam mechanism, as a result, computer technique improve the quality and speed of cam design and manufacture, that creates good conditions for cam mechanism’s widespread use, then promote automatic mechanism’s development preferably.By analyzing the feature of cam’s contour line, this paper proposes a machining solution of cam, and reasizes digital control processing about cam in Polar Coordinate by controling rotary motion and linear motion. It is easy to design cam’s contour line by utilizing angle and radius in Polar Coordinate. This plan avoids the conversion of Polar Coordinate and Rectangular Coordinate,and interpolates cam’s contour line by control rotary motion and linear motion. The algorithm of interpolation is data sampling interpolation, which judges axial direction and calculates axial incremental motion. Moreover, this paper also analyses the error of interpolation, and gives methods to control the error of interpolation, so makes every step interpolation always meat accuracy requirement.This paper designs control system too, which adopts combine mode of upper computer and lower computer. It makes use of PC’s powerful software and hardware function, to calculate interpolation of cam’s contour line, then obtains coordinates of nodal point and interpolation step size and so on,and conveys the information to PLC. Lastly, PLC controls actuating motor to move until finish machining. Because of coordinated control in the course of machining, this paper chooses FM357 as the positioning module, which controls four axis at the same time, so it meats system need.Finally, this paper amends equations of every law of motion becomingly, according to usual law of motion of cam outline curve, in order to meet the need of smooth transition, and writes generator programs of cam outline curve, then generates designed cam outline curve model, by using drawing function of MATLAB. Once having mathematical models of cam outline curve, then MATLAB can simulate the interpolation algorithm of cam outline curve, by using algorithm develop and math calculate capability of MATLAB. This paper compiles interpolation procedures, and controls real-time interpolation errors, then realizes dynamic simulation of cam’s contour line by using drawing function of MATLAB, and confirms feasibility of interpolation algorithm, besides, this paper also checkes validity of interpolation algorithm, by analyzing the interpolation results. In addition, this paper chooses VB to develop application software for PC, and designs interface of interpolation simulation, and compiles interface program of VB and MATLAB, as well as VB and PLC.更多还原