Nonlinear H(Infinity) Missile Longitudinal Autopilot Design with Theta-D Method

In this paper, a new nonlinear H 1 control technique, called μ¡D H 1 method, is employed to design a missile longitudinal autopilot. The μ ¡D H 1 design has the same structure as that of linear H 1 , except that the two Riccati equations that are part of the solution process are state dependent. The μ ¡D technique yields suboptimal solutions to nonlinear optimal control problems in the sense that it provides an approximate solution to the Hamilton-Jacobi-Bellman (HJB) equation. It is also shown that this method can be used to provide an approximate closed-form solution to the state dependent Riccati equation (SDRE) and consequently reduce the on-line computations associated with the nonlinear H 1 implementation. A missile longitudinal autopilot design demonstrates the capabilities of μ¡D method. This new nonlinear H 1 design also shows favorable results as compared with the linear H 1 design based on the linearized model.