%0 Journal Article %T Nonlinear Optimal Control Techniques Applied to a Launch Vehicle Autopilot %J Journal of Aerospace Science and Technology %I Iranian Aerospace Society %Z 1735-2134 %D 2006 %\ 03/01/2006 %V 3 %N 1 %P 43-49 %! Nonlinear Optimal Control Techniques Applied to a Launch Vehicle Autopilot %R %X This paper presents an application of the nonlinear optimal control techniques to the design of launch vehicle autopilots. The optimal control is given by the solution to the Hamilton-Jacobi-Bellman (HJB) equation, which in this case cannot be solved explicity. A method based upon Successive Galerkin Approximation (SGA), is used to obtain an approximate optimal solution. Simulation results involving three degrees of freedom (3DOF) model of a launch vehicle during atmospheric flight are reported to demonstrate the performance of the considered autopilot. Alternative results are also presented for classical and linear optimal approaches. %U https://jast.ias.ir/article_51509_b27089c3b86bb7386781cfcaadd8504c.pdf