11/15/18 3 Nominal and Actual Trajectories • Nominal (or reference) trajectory and control history {xN(t),u N(t),w N(t)}fortin[t o,t f] • Actual trajectory perturbed by –Small initial condition variation, Δx o(to) –Small control variation,Δu(t) {x(t),u(t),w(t)}fortin[to,t f] ={x N(t)+Δx(t),u N(t)+Δu(t),w N(t)+Δw(t)} x:dynamicstate u:controlinput w:disturbanceinput