Based on introducing structured parameter uncertainty problems into general H ∞ controller involving free parameters and taking into consideration of H 2 cost performance

a design method of mixed H ∞/H 2 controller with structured parameter uncertainty in the plant is presented.Necessary and sufficient conditions for solving corresponding problems are derived.It is shown that the solution to this problem involves solving three algebraic Riccati equations.Simulations on nonlinear model of twin spool turbojet engine aerothermodynamics are performed to verify the results.