说明：  arduino PID库。 可以直接调用而无需自行编写PID算法。PID（比例（proportion）、积分（integration）、微分（differentiation））控制器作为最早实用化的控制器已有近百年历史，现在仍然是应用最广泛的工业控制器。PID控制器简单易懂，使用中不需精确的系统模型等先决条件，因而成为应用最为广泛的控制器。
(arduino PID library. Can be called directly without having to write their own PID algorithm. PID (Proportional (proportion), integration (integration), differential (differentiation)) controller as the earliest practical controller for nearly a hundred years of history, and still is the most widely used industrial controllers. PID controller is easy to understand, use, without preconditions accurate system model, and thus become the most widely used controllers.)