Design, control and simulation of an airbrake system for apogee targeting in high-power rockets

Abstract

This work aims to define and simulate an active control system for a rocket competing in the European Rocketry Challenge. The competition rewards getting as close as possible to the prescribed apogee. In the S3 category, the target apogee is 3000 meters. For this reason, the Ares rocketry team, from UPC Space Program has decided to design an airbrake module that slows the rocket by deploying aerodynamic surfaces perpendicular to the vehicle. Accordingly, this work surveys the state of the art and the system’s feasibility, with the intention of achieving a straightforward implementation suited to the team’s available resources. The work analyzes and proposes possible solutions for the mechanical design and the electronics required to actuate the system. It also considers the integration of the module within the rocket. A preliminary study is carried out on how the deployment of the fins affects the vehicle’s stability. The main focus of the project is the design of a controller for the module. First, a Kalman filter is developed to reduce sensor noise and determine the system’s operational range. After validating the f ilter, an open-loop control is proposed, capable of selecting the optimal time for full deployment of the control surfaces. Finally, six-degree-of-freedom simulations are performed using RocketPy. The rocket’s trajectory and apogee are compared for flights with and without the active control device. The results show that, with this system, the rocket can reduce its apogee from about 3500 meters to the 3000 meters set by the competition. Lastly, although the results are viewed positively, several improvements and possible new implementations are proposed for future iterations.