Gain-scheduling autopilot design based on fixed-structure synthesis

A novel global gain-scheduling controller based on fixed-structure synthesis for missile autopilot has been presented in this paper. The original nonlinear control problem is going to be converted into a multi-model linear time invariant (LTI) structured-controller synthesis by fixed-structure synthesis. Missile three-loop autopilot structure and suitable performance constraints, including acceleration tracking, disturbances rejection, stability margin and pole constraints are considered. Nonsmooth optimization technique is utilized to overcome this multi-model synthesis problem. Gain surface tuning (GST) technique based on quadratic polynomial function of gain-scheduled parameters is applied to smooth the controller gains in order to avoid posteriori interpolation. Simulation results validate the effectiveness and robustness of the proposed method.