这是优达学城 PID 控制器项目实现，这个调试方法是做项目时，mentor 给的建议，实践中，效果还蛮不错~~

PID Controller

the project require to create a PID Controller for the vehicle on the high way.

PID effectons

1. P Controller is a based controller.

when the car ran with small cte, it had a small oscillation. But when the car truned the curve, the cte became larger and the controller began a big oscillation.

2. D Controller create small cte change rate;

3. I Controller, It sum a lot of cte;

To tune a PID, I will take some steps below:

step1:create a PID Controller class, and set the parameter of P's, I's, D's to zero;

step2: increase P gain until the response to a disturbance is steady oscillation;

step3: Increase the D gain until the oscillations go away;

step4: Repeat step2 and step 3, until increasing the D gain does not stop the oscillations;

step5: Increase the I gain until it brings you to the setpoint with the number of oscillations desired(normally zero);

实现代码：
https://github.com/luteresa/P8-PID-Control.git