Frequency-Domain Robust Performance Condition for Controller Uncertainty in SISO LTI Systems: A Geometric Approach

Table 2

Partitioning of search domain of 𝜔₁ in (21).

𝜔1 (rad)	LHS	RHS
−𝜋	0	+
−𝜃𝑃𝐾	+	0
0	0	+
𝜋−𝜃𝑃𝐾	+	0
𝜋	0	+