Lec 12. PID Controller Design PID Controller Ziegler-Nichols Tuning Rule Reading: 10.1, 10.2, TexPoint fonts used in EMF. Read the TexPoint manual before you delete this box.: AAAA

PID (Proportional-Integral-Derivative) Controller: Plant input : Three adjustable parameters: Often used for plant with unknown model PID Controller + plant controller

PID Tuning

First Method Obtain plant’s unit step response experimentally For many plants, unit step response is S-shaped –Delay time L –Time constant T

Determining L and T

Ziegler-Nichols Turning Rule (First Method) Type of Controller P PI PID (provided educated guesses for the parameter values)

Second Method (If no oscillation occurs for all values of K p, this method is not applicable) + plant controller

Ziegler-Nichols Turning Rule (Second Method) Type of Controller P PI PID (provided educated guesses for the parameter values)

Example PID controller (second method): + plant controller

Step Responses uncompensated compensated by

Example PID controller (first method):