* Generalized geometric programming * Robust stability problem * Daimler Benz bus, Ackermann et al. (1991) VARIABLES q1 q2 w frequency k stability margin a0 a1 a2 a3 a4 a5 a6 a7 a8 objval objective function variable; FREE VARIABLES objval; EQUATIONS f Objective function g1 g2 b1l b1u b2l b2u ga0 ga1 ga2 ga3 ga4 ga5 ga6 ga7 ga8; f .. objval =e=k; g1 .. a8*POWER(w,8) - a6*POWER(w,6) + a4*POWER(w,4) - a2*POWER(w,2) + a0 =e= 0; g2 .. a7*POWER(w,6) - a5*POWER(w,4) + a3*POWER(w,2) - a1 =e= 0; b1l .. -0.145*k - q1 =l= -0.175; b1u .. -0.145*k + q1 =l= 0.175; b2l .. -0.15*k - q2 =l= -0.2; b2u .. -0.15*k + q2 =l= 0.2; ga0 .. a0 =e= 4.53*POWER(q1,2); ga1 .. a1 =e= 5.28*POWER(q1,2) + 0.364*q1; ga2 .. a2 =e= 5.72*POWER(q1,2)*q2 + 1.13*POWER(q1,2) + 0.425*q1; ga3 .. a3 =e= 6.93*POWER(q1,2)*q2 + 0.0911*q1 + 0.00422; ga4 .. a4 =e= 1.45*POWER(q1,2)*q2 + 0.168*q1*q2 + 0.000338; ga5 .. a5 =e= 1.56*POWER(q1,2)*POWER(q2,2) + 0.00084*POWER(q1,2)*q2 + 0.0135*q1*q2 + 1.35e-05; ga6 .. a6 =e= 0.125*POWER(q1,2)*POWER(q2,2) + 1.68e-05*POWER(q1,2)*q2 + 0.000539*q1*q2 + 2.7e-07; ga7 .. a7 =e= 0.005*POWER(q1,2)*POWER(q2,2) + 1.08e-05*q1*q2; ga8 .. a8 =e= 0.0001*POWER(q1,2)*POWER(q2,2); * Bounds w.LO = 0; w.UP = 10; MODEL test /ALL/; SOLVE test USING NLP MINIMIZING objval;