pid控制器自整定理论，英文论著。论述的十分到位，对研究pid自整定是很好的资料。-Self-tuning pid controllers theory, English literature. On the very place, the study of self-tuning pid is a very good information.

Here an example of a modified PID controllers (take into account the winding integral term)

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

Two Area power interconnected power system load frequency control using PID controllers

PID tuning code with controllers