Non conservative robustness evaluation of a multivariable H∞ missile autopilot

A multivariable missile autopilot is synthesized using a H_∞ approach. The design takes into account realistic limits in the dynamics of the actuators and bending modes. Robustness of the control law is studied, with emphasis on real parametric uncertainties in the stability derivatives: different techniques (complex μ analysis, mixed μ analysis techniques, Dailey´s (1990) and De Gaston and Safonov´s (1988) methods) are used to compute either an interval or the exact value of the real structured singular value (SSV). An example of discontinuity of the SSV is interpreted using classical root loci. The control law is finally validated on a nonlinear simulator.