9360677 Lin The nonlinearity and uncertainty inherent in a complex dynamic system have been a great challenge to the autopilot design that is required to have satisfactory performance for all flight conditions in probable engagements. Several advanced robust nonlinear approaches, namely, inversion- based control laws, analytical gain scheduling, and nonlinear servo-regulator are proposed to design a high performance autopilot. The unique features of these approaches include that (1) they incorporate the nonlinear dynamics due to severe kinematic and inertial coupling as well as aerodynamics into the design process; (2) they furnish robust scheme to account for model uncertainties due to aerodynamics and bending motion, etc.; and (3) they provide adaptive mechanism to handle parameter variations of the mass and inertia, etc. Each of these features works to enhance the performance of complex dynamic system. The deliverables include a comprehensive nonlinear design/analysis tool together with detailed documentations and training courses.