1. 4.1 Stability
Routh Tabulation
Example 4.1
For stability, real part of the roots < 0
All coefficients have the same sign and they should be different from zero

2. All values in 1st column have the same sign
Number of positive roots is equal to the number of sign change.
4.2 Ziegler-Nichols Design
(Thompson, Sh. 127)
Kc: Critical K Tc: Oscilation period

3. Example 4.2 ) s ( R
GC(s): P, PI or PID control (Ziegler-Nichols design)
Routh Table:
>> a=[1,6,11,66];roots(a)
P control:

4. PI control:
PID control: