基于基线交换的光学变焦驱动设计

Baseline exchanging in optical zoom cam curves design

常用的两运动组元等间距光学变焦驱动设计方法和等程距设计方法都存在曲线局部压力角难以控制的问题。论述一种基于基线交换的光学变焦驱动设计方法,该方法通过在合适的变焦曲线位置交换基线(主驱动曲线),从而解决曲线局部压力角(曲线在光轴方向切角的余角)控制的问题,保证了整个变焦过程中的主驱动曲线压力角一致性、扭矩力均匀性和变焦平滑性,同时不降低变焦过程的快速性。讨论了辅助程序设计的实现情况和实践中出现的问题的解决途径。理论和实践证明,这种变焦驱动设计方法是一种效果颇佳的设计优化手段。

The Pressure angle in local cam curve is extra large in Same-Pitch or Equiangular optical zoom cam curve design,which makes the zoom cam system drop in bad optimizing status.This article gives a new method which basing on baseline exchanging of optical zoom cam couple curves to deal with this difficulty.After zoom curve linearly designing,special couple points can be found on couple curves which has same pressure angle.At this point,the compensatory curve is linearly designed.It ensures the pressure angle in couple curves in control and the max pressure angle is unique,which make the cam drive moment symmetrical and smoothly.Finally,the article gives a program solution.Theory and practice prove that the method and program is quite practical.