Linear Parameter-Varying Control of the VEGA Launch Vehicle
Translated title
Lineær Parameter-Varierende Kontrol af VEGA-raketten
Author
Poulsen, Jakob Stentoft
Term
4. term
Education
Publication year
2021
Submitted on
2021-06-03
Pages
75
Abstract
This thesis develops a Linear Parameter-Varying (LPV) control system for the European launch vehicle VEGA. The goal is to keep the vehicle stable during atmospheric flight from liftoff to Main Engine Cut Off (MECO), even in the presence of disturbances such as wind gusts, sensor noise, and computational delays. The work builds a physics-based model of the rocket’s motion in three dimensions with six degrees of freedom (three translations and three rotations). The model is simplified to two dimensions and mathematically linearized (Jacobian linearization) to obtain a linear state-space representation suitable for controller design. Standard ascent requirements for a typical launch vehicle are then established. An LPV controller is designed in a lower Linear Fractional Transform (LFT) configuration and augmented with frequency-dependent filters on the input and output channels to meet these requirements. Finally, the control system is evaluated in linear LPV simulations with user-specified inputs. Simulation results indicate that VEGA remains stable and operates as intended while meeting the stated requirements.
Dette speciale udvikler et lineært parameter-varierende (LPV) styresystem til den europæiske bæreraket VEGA. Målet er at holde raketten stabil under flyvning i atmosfæren fra liftoff til MECO (slukning af hovedmotor), selv når der er forstyrrelser som vindstød, sensorstøj og beregningsforsinkelser. Arbejdet omfatter en fysisk model af rakettens bevægelse i tre dimensioner med seks frihedsgrader (tre bevægelser og tre rotationer). Modellen forenkles til to dimensioner og linearisers matematisk (Jacobi-linearisering) for at opnå en lineær tilstandsrum-beskrivelse, som er velegnet til regulatorudvikling. Der opstilles derefter velkendte krav til en typisk bæreraket under opstigning. På denne baggrund designes en LPV-regulator i en lower Linear Fractional Transform (LFT) konfiguration, og den udbygges med frekvensafhængige filtre på ind- og udgangskanalerne for at opfylde kravene. Til sidst afprøves styresystemet i lineære LPV-simuleringer med brugerdefinerede scenarier. Resultaterne viser, at VEGA forbliver stabil og fungerer som tilsigtet i simuleringerne og opfylder de opstillede krav.
[This apstract has been rewritten with the help of AI based on the project's original abstract]