说明：  带死区控制的PID算法.由于是用整型数来做的，所以也不是很精确，但是对于很多的使用场合，这个精度也够了。关于系数和采样电压全部是放大10倍处理的。所以精度不是很高，但是也不是那么低，大部分的场合都够用了。实在觉得精度不够，可以再放大10倍或者100倍处理，但是要注意不超出整个数据类型的范围就可以了。
(Dead-zone PID control algorithm. Because it is done with integers, so are not very accurate, but the use for many occasions, the accuracy is also enough. On the coefficient and sample voltages are all dealt with 10 times larger. So accuracy is not very high, but it is not so low, most of the occasions enough. Really feel that accuracy is not enough, you can be 10 times or 100 times larger deal, but be careful not to exceed the scope of the entire data type on it.)