01.Settling Time (ts): 2% criterion ts ≈ 4/(ζωn), or 1% criterion ts ≈ 4.6/(ζωn)
02.Peak Overshoot (Mp): Mp = exp(−πζ/√(1−ζ²)) × 100%
03.Rise Time (tr): time from 10% to 90% of final value (overdamped) or 0% to 100% (underdamped)
04.Steady-State Error (e_ss): use Final Value Theorem — lim(s→0) sE(s)