In this paper, a new nonlinear control synthesis technique, the theta- D method, is employed to design a missile longitudinal autopilot. The θ-D technique yields suboptimal solutions to nonlinear optimal control problems in the sense that it provides approximate solution to the Hamilton-Jacobi-Bellman (HJB) equation. Semi-global asymptotic stability can be achieved by manipulating the perturbation terms which are added to the cost function in developing a series solution. Furthermore, this method can be used to provide an approximate closed-form solution to the state dependent Riccati equation. The particular θ-D methodology adopted in this paper is referred to as θ-D H infinity design. The θ-D H infinity design has the same structure as that of linear H infinity, except that the two Riccati equations are state dependent. By using the θ-D technique, we would eliminate the need for online computations of Riccati equations as in the recently popular state dependent Riccati equation technique. A missile longitudinal autopilot design demonstrates the capabilities of θ-D method.

Meeting Name

2003 American Control Conference, 2003


Mechanical and Aerospace Engineering

Keywords and Phrases

Hamilton-Jacobi-Bellman Equation; Riccati Equations; Approximate Closed Form Solution; Approximation Theory; Asymptotic Stability; Control System Synthesis; Cost Function; Missile Autopilot Design; Missile Control; Nonlinear Control; Nonlinear Control Systems; Optimal Control; Perturbation Techniques; Perturbation Terms; Semiglobal Asymptotic Stability; State Dependent Riccati Equation Technique; Suboptimal Control; Theta - D Technique

International Standard Serial Number (ISSN)


Document Type

Article - Conference proceedings

Document Version

Final Version

File Type





© 2003 Institute of Electrical and Electronics Engineers (IEEE), All rights reserved.

Publication Date

01 Jan 2003