Title

Theta-D Control Technique for Ascent Phase of Reusable Launch Vehicles

Abstract

Current flight control of reusable launch vehicles is based on table look-up gains for specific flight conditions. A new suboptimal nonlinear control technique for the complete ascent phase of reusable launch vehicles is presented in this paper. The new technique, called the θ-D method, is synthesized by adding perturbations to a typical optimal control formulation with a quadratic cost function. The controller expressions are obtained by getting an approximate closed-form solution to the Hamilton-Jacobi-Bellman equation. The θ-D method avoids iterative online solutions. A controller using this new method has been designed for the ascent phase of a reusable launch vehicle and implemented in a six degrees-of-freedom high fidelity simulator being run at the NASA Marshall Space Flight Center. Simulation results show that the θ-D controller achieves accurate tracking for the ascent phase of the reusable launch vehicle while being robust to external disturbances and plant uncertainties.

Department(s)

Mechanical and Aerospace Engineering

Keywords and Phrases

Ascent Phase; Reusable Launch Vehicles; Θ-D Method

Document Type

Article - Conference proceedings

Document Version

Citation

File Type

text

Language(s)

English

Rights

© 2004 American Institute of Aeronautics and Astronautics (AIAA), All rights reserved.

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