PID controller tuning by using Ziegler-Nichols method.

1. PID Tuning using Ziegler-Nichols
Method
Subject – Control System
Kaustubha H. Shedbalkar
8/16/2023 PID Tuning using Z- N method

2. Ziegler Nicholas Methods -
 Step Input method/ Open loop method.
 Critical gain - critical period method/ Close
loop method.
8/16/2023 PID Tuning using Z- N method

3. Step Input method/ Open loop
method
8/16/2023 PID Tuning using Z- N method

4. Step Input method/ Open loop
method
8/16/2023 PID Tuning using Z- N method

5. • In this method, we obtain experimentally the
response of the plant as shown in fig. This method
applies if the response to a step input exhibits an
S-Shaped curve.
• The S-Shaped curve may be characterized by two
constants, Delay time (L) & Time constant (T). It is
determined by drawing a tangent line at the
inflection point of S-Shaped curve & determining
the intersection of tangent line with time axis &
line K on Y-axis. The Ziegler-Nichols suggested, we
set the value of parameter Kp, Ti, Td according to
the formula shown in table.
8/16/2023 PID Tuning using Z- N method

6. Step Input method/ Open loop
method
8/16/2023 PID Tuning using Z- N method

7. Critical gain - critical period method/
Close loop method
8/16/2023 PID Tuning using Z- N method

8. Critical gain - critical period method/
Close loop method
8/16/2023 PID Tuning using Z- N method

9. 8/16/2023 PID Tuning using Z- N method
• In this method, suppose PID controller is used in
the system then Ti is set to infinity & Td is set to
zero. Using proportional control action only,
increase Kp from zero to critical value Kcr at which
the output first exhibits sustained oscillations.
• The critical gain Kcr & corresponding time period
Pcr are determined.
•The Ziegler-Nichols suggested, we set the value of
parameter Kp, Ti, Td according to the formula
shown in table.

10. Critical gain - critical period method/
Close loop method
8/16/2023 PID Tuning using Z- N method

11. Thank You.
8/16/2023 PID Tuning using Z- N method