ADCS Design for a Sounding Rocket with Thrust Vectoring

Pedro Emanuel Moutinho dos Santos

Key information

Authors:

Pedro Emanuel Moutinho dos Santos (Pedro Emanuel Moutinho dos Santos)

Supervisors:

Paulo Jorge Coelho Ramalho Oliveira (Paulo Jorge Coelho Ramalho Oliveira)

Published in

12/15/2022

Abstract

This thesis concerns the development of an attitude determination and control system (ADCS) for a sounding rocket using Thrust Vector Control (TVC). The main motivation was the inclusion of the designed system in a future sounding rocket, to be developed by a student rocketry team from the Aerospace Engineering Student's Association of Instituto Superior Técnico (AeroTéc), named Rocket Experiment Division (RED). To design the ADCS, a non-linear six-degrees-of-freedom model for the rocket dynamics and kinematics is deduced and implemented in simulation environment using MATLAB and Simulink. The attitude control system design is done using the derived linear, time-varying, state-space representation of the rocket. An optimal controller is designed using the linear quadratic regulator (LQR) with an additional integral action. This controller was tested in the simulation environment and demonstrated satisfactory attitude tracking performance, and robustness to model uncertainties, significantly outperforming the classical proportional-integral-derivative (PID) control solution. A linear parameter estimator is implemented to provide real-time estimates on the aerodynamic forces and moments. These estimates are then used to develop an adaptive controller that computes in real-time the gains, after correcting the state-space model. The adaptive controller did not show significant performance improvement due to the already high robustness of the original controller. Finally, a navigation system is designed, based on measurements available onboard, to provide accurate estimates on the rocket's state. The ADCS is the result of the integration of the attitude control and navigation systems, with the complete system being implemented and tested in simulation and demonstrating satisfactory performance.