Ziegler spectrum

The Ziegler spectrum refers to a concept in control theory related to the stability and performance of control systems. It is derived from the Ziegler-Nichols tuning method, which is a popular heuristic approach for tuning the parameters of PID (Proportional-Integral-Derivative) controllers. **Ziegler-Nichols Method:** 1. The Ziegler-Nichols method involves determining the critical gain (Ku) and the oscillation period (Tu) of a system.