说明：  迭代学习程序，用迭代实现一个简单的控制，结果表明控制效果十分好
(Iterative learning process in matlab，a simple case，so easy，use a short method，how i need to write，so hard！Iterative learning process in matlab，a simple case，so easy，use a short method，how i need to write，so hardIterative learning process in matlab，a simple case，so easy，use a short method，how i need to write，so hard)