变焦凸轮曲线的优化设计方法

变焦凸轮是变焦镜头中驱动各个镜组运动的关键部件，凸轮曲线的设计结果决定了变焦系统的运动性能、系统精度以及系统成像等方面的特性，因此，变焦凸轮的设计是变焦距镜头设计中重要环节之一，优良的凸轮性能是实现镜头光学设计像质目标和连续变焦过程的基本要求。为了设计出优良的曲线形态以确保凸轮具有较小的压力角，使变焦过程平滑稳定、运动流畅，既能有效减小变焦系统的驱动力矩，又可以确保变焦成像的稳定性。在凸轮设计过程中，分别构造凸轮变倍组和补偿组驱动力矩与各自压力角的函数表达式，再以它们的函数组合构造整体目标优化函数，优化计算变倍曲线压力角与补偿曲线压力角的最优值，优化计算结果表明，优化后凸轮等效驱动力矩显著减小，能够有效改善变焦凸轮的整体性能。

Optimization design method of cam curve for zoom lens

Zoom cam is a pivotal part used for driving every lens group in zoom lens,the design result of cam curve is decisive importance for motion property and system precision as well as system imaging in zoom system, therefore, zoom cam design is an important part of the zoom lens design, a fine cam performance is the basic requirements to reach lens design of image quality goal and optical zoom process. In order to design a excellent curve form to ensure the pressure angle was smaller, make the process stability and movement smooth fluent, reduce the zoom systems driving moment, and ensure a stability zoom imaging, in the cam design process, we constructed functions which were driving moments of variable group and compensation group with their own pressure angle. Then, combination goal optimization function was built, optimal values of variable group curve pressure angle and compensation group curve pressure angle were optimized and calculated. Optimization results show that the cam drive moment significantly reduces, and improve the overall performance of zoom cam is improved.