Determining the ultimate gain value, ku,. Also, measure the period of oscillation, pu, referred to as. Use the ultimate gain ku (sustained oscillation gain) and ultimate period tu to set kp, ki, kd directly.
Ziegler-Nichols Closed-Loop Method (Ultimate Gain) - Inst Tools
It was developed by john g
It is performed by setting the i (integral) and d (derivative) gains to zero.
1/4 decay ratio may be too much, that is, the damping in the loop is too small. When a value of kc results in a sustained periodic oscillation in the output (or close to it), mark this critical value of kc as ku, the ultimate gain
