Theta-D Control Technique for Ascent Phase of Reusable Launch Vehicles
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.
D. Drake et al., "Theta-D Control Technique for Ascent Phase of Reusable Launch Vehicles," AIAA Guidance, Navigation, and Control Conference and Exhibit, American Institute of Aeronautics and Astronautics (AIAA), Dec 2004.
Mechanical and Aerospace Engineering
Keywords and Phrases
Ascent Phase; Reusable Launch Vehicles; Θ-D Method
Article - Conference proceedings
© 2004 American Institute of Aeronautics and Astronautics (AIAA), All rights reserved.